From 312db1aa1dc7bff133d95c92efcc5e42b57cefa6 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski
Date: Sun, 11 Mar 2018 11:34:39 +0100
Subject: fs: add ksys_mount() helper; remove in-kernel calls to sys_mount()

Using this helper allows us to avoid the in-kernel calls to the sys_mount()
syscall. The ksys_ prefix denotes that this function is meant as a drop-in
replacement for the syscall. In particular, it uses the same calling
convention as sys_mount().

In the near future, all callers of ksys_mount() should be converted to call
do_mount() directly.

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 init/do_mounts.c        | 4 ++--
 init/do_mounts_initrd.c | 6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

(limited to 'init')

diff --git a/init/do_mounts.c b/init/do_mounts.c
index 7cf4f6dafd5f..eb768de43d84 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -363,7 +363,7 @@ static void __init get_fs_names(char *page)
 static int __init do_mount_root(char *name, char *fs, int flags, void *data)
 {
 	struct super_block *s;
-	int err = sys_mount(name, "/root", fs, flags, data);
+	int err = ksys_mount(name, "/root", fs, flags, data);
 	if (err)
 		return err;
 
@@ -599,7 +599,7 @@ void __init prepare_namespace(void)
 	mount_root();
 out:
 	devtmpfs_mount("dev");
-	sys_mount(".", "/", NULL, MS_MOVE, NULL);
+	ksys_mount(".", "/", NULL, MS_MOVE, NULL);
 	sys_chroot(".");
 }
 
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index 53d4f0f326e7..7868a6039fb4 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -43,7 +43,7 @@ static int init_linuxrc(struct subprocess_info *info, struct cred *new)
 	sys_dup(0);
 	/* move initrd over / and chdir/chroot in initrd root */
 	sys_chdir("/root");
-	sys_mount(".", "/", NULL, MS_MOVE, NULL);
+	ksys_mount(".", "/", NULL, MS_MOVE, NULL);
 	sys_chroot(".");
 	sys_setsid();
 	return 0;
@@ -81,7 +81,7 @@ static void __init handle_initrd(void)
 	current->flags &= ~PF_FREEZER_SKIP;
 
 	/* move initrd to rootfs' /old */
-	sys_mount("..", ".", NULL, MS_MOVE, NULL);
+	ksys_mount("..", ".", NULL, MS_MOVE, NULL);
 	/* switch root and cwd back to / of rootfs */
 	sys_chroot("..");
 
@@ -95,7 +95,7 @@ static void __init handle_initrd(void)
 	mount_root();
 
 	printk(KERN_NOTICE "Trying to move old root to /initrd ... ");
-	error = sys_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);
+	error = ksys_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);
 	if (!error)
 		printk("okay\n");
 	else {
-- 
cgit v1.2.3


From 3a18ef5c1b3935cb05888fc37964321f7bd6231d Mon Sep 17 00:00:00 2001
From: Dominik Brodowski
Date: Sun, 11 Mar 2018 11:34:40 +0100
Subject: fs: add ksys_umount() helper; remove in-kernel call to sys_umount()

Using this helper allows us to avoid the in-kernel call to the sys_umount()
syscall. The ksys_ prefix denotes that this function is meant as a drop-in
replacement for the syscall. In particular, it uses the same calling
convention as ksys_umount().

In the near future, the only fs-external caller of ksys_umount() should be
converted to call do_umount() directly. Then, ksys_umount() can be moved
within sys_umount() again.

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/namespace.c           | 9 +++++++--
 include/linux/syscalls.h | 1 +
 init/do_mounts_initrd.c  | 2 +-
 3 files changed, 9 insertions(+), 3 deletions(-)

(limited to 'init')

diff --git a/fs/namespace.c b/fs/namespace.c
index 642b8b229944..e398f32d7541 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1680,7 +1680,7 @@ static inline bool may_mandlock(void)
  * unixes. Our API is identical to OSF/1 to avoid making a mess of AMD
  */
 
-SYSCALL_DEFINE2(umount, char __user *, name, int, flags)
+int ksys_umount(char __user *name, int flags)
 {
 	struct path path;
 	struct mount *mnt;
@@ -1720,6 +1720,11 @@ out:
 	return retval;
 }
 
+SYSCALL_DEFINE2(umount, char __user *, name, int, flags)
+{
+	return ksys_umount(name, flags);
+}
+
 #ifdef __ARCH_WANT_SYS_OLDUMOUNT
 
 /*
@@ -1727,7 +1732,7 @@ out:
  */
 SYSCALL_DEFINE1(oldumount, char __user *, name)
 {
-	return sys_umount(name, 0);
+	return ksys_umount(name, 0);
 }
 
 #endif
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 3a9f9c534624..48964c408c7b 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -948,5 +948,6 @@ asmlinkage long sys_statx(int dfd, const char __user *path, unsigned flags,
 
 int ksys_mount(char __user *dev_name, char __user *dir_name, char __user *type,
 	       unsigned long flags, void __user *data);
+int ksys_umount(char __user *name, int flags);
 
 #endif
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index 7868a6039fb4..1c4da8353332 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -105,7 +105,7 @@ static void __init handle_initrd(void)
 		else
 			printk("failed\n");
 		printk(KERN_NOTICE "Unmounting old root\n");
-		sys_umount("/old", MNT_DETACH);
+		ksys_umount("/old", MNT_DETACH);
 		printk(KERN_NOTICE "Trying to free ramdisk memory ... ");
 		if (fd < 0) {
 			error = fd;
-- 
cgit v1.2.3


From c7248321a3d42ffba78db0dde88d1c49ca1c045f Mon Sep 17 00:00:00 2001
From: Dominik Brodowski
Date: Sun, 11 Mar 2018 11:34:40 +0100
Subject: fs: add ksys_dup{,3}() helper; remove in-kernel calls to
 sys_dup{,3}()

Using ksys_dup() and ksys_dup3() as helper functions allows us to
avoid the in-kernel calls to the sys_dup() and sys_dup3() syscalls.
The ksys_ prefix denotes that these functions are meant as a drop-in
replacement for the syscalls. In particular, they use the same
calling convention as sys_dup{,3}().

In the near future, the fs-external callers of ksys_dup{,3}() should be
converted to call do_dup2() directly. Then, ksys_dup{,3}() can be moved
within sys_dup{,3}() again.

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/file.c                | 16 +++++++++++++---
 include/linux/syscalls.h |  1 +
 init/do_mounts_initrd.c  |  4 ++--
 init/main.c              |  4 ++--
 4 files changed, 18 insertions(+), 7 deletions(-)

(limited to 'init')

diff --git a/fs/file.c b/fs/file.c
index 42f0db4bd0fb..d304004f0b65 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -870,7 +870,7 @@ out_unlock:
 	return err;
 }
 
-SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags)
+static int ksys_dup3(unsigned int oldfd, unsigned int newfd, int flags)
 {
 	int err = -EBADF;
 	struct file *file;
@@ -904,6 +904,11 @@ out_unlock:
 	return err;
 }
 
+SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags)
+{
+	return ksys_dup3(oldfd, newfd, flags);
+}
+
 SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd)
 {
 	if (unlikely(newfd == oldfd)) { /* corner case */
@@ -916,10 +921,10 @@ SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd)
 		rcu_read_unlock();
 		return retval;
 	}
-	return sys_dup3(oldfd, newfd, 0);
+	return ksys_dup3(oldfd, newfd, 0);
 }
 
-SYSCALL_DEFINE1(dup, unsigned int, fildes)
+int ksys_dup(unsigned int fildes)
 {
 	int ret = -EBADF;
 	struct file *file = fget_raw(fildes);
@@ -934,6 +939,11 @@ SYSCALL_DEFINE1(dup, unsigned int, fildes)
 	return ret;
 }
 
+SYSCALL_DEFINE1(dup, unsigned int, fildes)
+{
+	return ksys_dup(fildes);
+}
+
 int f_dupfd(unsigned int from, struct file *file, unsigned flags)
 {
 	int err;
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 48964c408c7b..50876ae1d17b 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -949,5 +949,6 @@ asmlinkage long sys_statx(int dfd, const char __user *path, unsigned flags,
 int ksys_mount(char __user *dev_name, char __user *dir_name, char __user *type,
 	       unsigned long flags, void __user *data);
 int ksys_umount(char __user *name, int flags);
+int ksys_dup(unsigned int fildes);
 
 #endif
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index 1c4da8353332..e8573e1776f6 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -39,8 +39,8 @@ static int init_linuxrc(struct subprocess_info *info, struct cred *new)
 	sys_unshare(CLONE_FS | CLONE_FILES);
 	/* stdin/stdout/stderr for /linuxrc */
 	sys_open("/dev/console", O_RDWR, 0);
-	sys_dup(0);
-	sys_dup(0);
+	ksys_dup(0);
+	ksys_dup(0);
 	/* move initrd over / and chdir/chroot in initrd root */
 	sys_chdir("/root");
 	ksys_mount(".", "/", NULL, MS_MOVE, NULL);
diff --git a/init/main.c b/init/main.c
index 969eaf140ef0..b8649d1466e1 100644
--- a/init/main.c
+++ b/init/main.c
@@ -1077,8 +1077,8 @@ static noinline void __init kernel_init_freeable(void)
 	if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
 		pr_err("Warning: unable to open an initial console.\n");
 
-	(void) sys_dup(0);
-	(void) sys_dup(0);
+	(void) ksys_dup(0);
+	(void) ksys_dup(0);
 	/*
 	 * check if there is an early userspace init.  If yes, let it do all
 	 * the work
-- 
cgit v1.2.3


From a16fe33ab5572e52ef4cb9719d6eb49623b2528a Mon Sep 17 00:00:00 2001
From: Dominik Brodowski
Date: Sun, 11 Mar 2018 11:34:41 +0100
Subject: fs: add ksys_chroot() helper; remove-in kernel calls to sys_chroot()

Using this helper allows us to avoid the in-kernel calls to the
sys_chroot() syscall. The ksys_ prefix denotes that this function is
meant as a drop-in replacement for the syscall. In particular, it uses the
same calling convention as sys_chroot().

In the near future, the fs-external callers of ksys_chroot() should be
converted to use kern_path()/set_fs_root() directly. Then ksys_chroot()
can be moved within sys_chroot() again.

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 drivers/base/devtmpfs.c  | 2 +-
 fs/open.c                | 7 ++++++-
 include/linux/syscalls.h | 1 +
 init/do_mounts.c         | 2 +-
 init/do_mounts_initrd.c  | 4 ++--
 5 files changed, 11 insertions(+), 5 deletions(-)

(limited to 'init')

diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index 4afb04686c8e..5743f04014ca 100644
--- a/drivers/base/devtmpfs.c
+++ b/drivers/base/devtmpfs.c
@@ -387,7 +387,7 @@ static int devtmpfsd(void *p)
 	if (*err)
 		goto out;
 	sys_chdir("/.."); /* will traverse into overmounted root */
-	sys_chroot(".");
+	ksys_chroot(".");
 	complete(&setup_done);
 	while (1) {
 		spin_lock(&req_lock);
diff --git a/fs/open.c b/fs/open.c
index 7ea118471dce..7a475e8a2e41 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -479,7 +479,7 @@ out:
 	return error;
 }
 
-SYSCALL_DEFINE1(chroot, const char __user *, filename)
+int ksys_chroot(const char __user *filename)
 {
 	struct path path;
 	int error;
@@ -512,6 +512,11 @@ out:
 	return error;
 }
 
+SYSCALL_DEFINE1(chroot, const char __user *, filename)
+{
+	return ksys_chroot(filename);
+}
+
 static int chmod_common(const struct path *path, umode_t mode)
 {
 	struct inode *inode = path->dentry->d_inode;
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 50876ae1d17b..920a0db1871d 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -950,5 +950,6 @@ int ksys_mount(char __user *dev_name, char __user *dir_name, char __user *type,
 	       unsigned long flags, void __user *data);
 int ksys_umount(char __user *name, int flags);
 int ksys_dup(unsigned int fildes);
+int ksys_chroot(const char __user *filename);
 
 #endif
diff --git a/init/do_mounts.c b/init/do_mounts.c
index eb768de43d84..2f06f7827b0c 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -600,7 +600,7 @@ void __init prepare_namespace(void)
 out:
 	devtmpfs_mount("dev");
 	ksys_mount(".", "/", NULL, MS_MOVE, NULL);
-	sys_chroot(".");
+	ksys_chroot(".");
 }
 
 static bool is_tmpfs;
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index e8573e1776f6..71293265ac4b 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -44,7 +44,7 @@ static int init_linuxrc(struct subprocess_info *info, struct cred *new)
 	/* move initrd over / and chdir/chroot in initrd root */
 	sys_chdir("/root");
 	ksys_mount(".", "/", NULL, MS_MOVE, NULL);
-	sys_chroot(".");
+	ksys_chroot(".");
 	sys_setsid();
 	return 0;
 }
@@ -83,7 +83,7 @@ static void __init handle_initrd(void)
 	/* move initrd to rootfs' /old */
 	ksys_mount("..", ".", NULL, MS_MOVE, NULL);
 	/* switch root and cwd back to / of rootfs */
-	sys_chroot("..");
+	ksys_chroot("..");
 
 	if (new_decode_dev(real_root_dev) == Root_RAM0) {
 		sys_chdir("/old");
-- 
cgit v1.2.3


From e7a3e8b2edf544ec28f689385c3adc2903f46ec0 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski
Date: Sun, 11 Mar 2018 11:34:41 +0100
Subject: fs: add ksys_write() helper; remove in-kernel calls to sys_write()

Using this helper allows us to avoid the in-kernel calls to the sys_write()
syscall. The ksys_ prefix denotes that this function is meant as a drop-in
replacement for the syscall. In particular, it uses the same calling
convention as sys_write().

In the near future, the do_mounts / initramfs callers of ksys_write()
should be converted to use filp_open() and vfs_write() instead.

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-s390@vger.kernel.org
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 arch/s390/kernel/compat_linux.c | 2 +-
 fs/read_write.c                 | 9 +++++++--
 include/linux/syscalls.h        | 1 +
 init/do_mounts_rd.c             | 4 ++--
 init/initramfs.c                | 2 +-
 5 files changed, 12 insertions(+), 6 deletions(-)

(limited to 'init')

diff --git a/arch/s390/kernel/compat_linux.c b/arch/s390/kernel/compat_linux.c
index 79b7a3438d54..5a9cfde5fc28 100644
--- a/arch/s390/kernel/compat_linux.c
+++ b/arch/s390/kernel/compat_linux.c
@@ -468,7 +468,7 @@ COMPAT_SYSCALL_DEFINE3(s390_write, unsigned int, fd, const char __user *, buf, c
 	if ((compat_ssize_t) count < 0)
 		return -EINVAL; 
 
-	return sys_write(fd, buf, count);
+	return ksys_write(fd, buf, count);
 }
 
 /*
diff --git a/fs/read_write.c b/fs/read_write.c
index f8547b82dfb3..8e8f0b4f52e2 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -578,8 +578,7 @@ SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count)
 	return ret;
 }
 
-SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf,
-		size_t, count)
+ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count)
 {
 	struct fd f = fdget_pos(fd);
 	ssize_t ret = -EBADF;
@@ -595,6 +594,12 @@ SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf,
 	return ret;
 }
 
+SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf,
+		size_t, count)
+{
+	return ksys_write(fd, buf, count);
+}
+
 SYSCALL_DEFINE4(pread64, unsigned int, fd, char __user *, buf,
 			size_t, count, loff_t, pos)
 {
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 920a0db1871d..80524faa9664 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -951,5 +951,6 @@ int ksys_mount(char __user *dev_name, char __user *dir_name, char __user *type,
 int ksys_umount(char __user *name, int flags);
 int ksys_dup(unsigned int fildes);
 int ksys_chroot(const char __user *filename);
+ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count);
 
 #endif
diff --git a/init/do_mounts_rd.c b/init/do_mounts_rd.c
index 99e0b649fc0e..2d365c398ccc 100644
--- a/init/do_mounts_rd.c
+++ b/init/do_mounts_rd.c
@@ -270,7 +270,7 @@ int __init rd_load_image(char *from)
 			printk("Loading disk #%d... ", disk);
 		}
 		sys_read(in_fd, buf, BLOCK_SIZE);
-		sys_write(out_fd, buf, BLOCK_SIZE);
+		ksys_write(out_fd, buf, BLOCK_SIZE);
 #if !defined(CONFIG_S390)
 		if (!(i % 16)) {
 			pr_cont("%c\b", rotator[rotate & 0x3]);
@@ -317,7 +317,7 @@ static long __init compr_fill(void *buf, unsigned long len)
 
 static long __init compr_flush(void *window, unsigned long outcnt)
 {
-	long written = sys_write(crd_outfd, window, outcnt);
+	long written = ksys_write(crd_outfd, window, outcnt);
 	if (written != outcnt) {
 		if (decompress_error == 0)
 			printk(KERN_ERR
diff --git a/init/initramfs.c b/init/initramfs.c
index 7e99a0038942..6f972df15bf2 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -27,7 +27,7 @@ static ssize_t __init xwrite(int fd, const char *p, size_t count)
 
 	/* sys_write only can write MAX_RW_COUNT aka 2G-4K bytes at most */
 	while (count) {
-		ssize_t rv = sys_write(fd, p, count);
+		ssize_t rv = ksys_write(fd, p, count);
 
 		if (rv < 0) {
 			if (rv == -EINTR || rv == -EAGAIN)
-- 
cgit v1.2.3


From 447016e9681965fda8dcd9e4fd3c55308a6fd166 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski
Date: Sun, 11 Mar 2018 11:34:46 +0100
Subject: fs: add ksys_chdir() helper; remove in-kernel calls to sys_chdir()

Using this helper allows us to avoid the in-kernel calls to the sys_chdir()
syscall. The ksys_ prefix denotes that this function is meant as a drop-in
replacement for the syscall. In particular, it uses the same calling
convention as sys_chdir().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 drivers/base/devtmpfs.c  | 2 +-
 fs/open.c                | 7 ++++++-
 include/linux/syscalls.h | 1 +
 init/do_mounts.c         | 2 +-
 init/do_mounts_initrd.c  | 8 ++++----
 5 files changed, 13 insertions(+), 7 deletions(-)

(limited to 'init')

diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index 5743f04014ca..3f7ee954fd2c 100644
--- a/drivers/base/devtmpfs.c
+++ b/drivers/base/devtmpfs.c
@@ -386,7 +386,7 @@ static int devtmpfsd(void *p)
 	*err = ksys_mount("devtmpfs", "/", "devtmpfs", MS_SILENT, options);
 	if (*err)
 		goto out;
-	sys_chdir("/.."); /* will traverse into overmounted root */
+	ksys_chdir("/.."); /* will traverse into overmounted root */
 	ksys_chroot(".");
 	complete(&setup_done);
 	while (1) {
diff --git a/fs/open.c b/fs/open.c
index 7a475e8a2e41..a19b8277c439 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -431,7 +431,7 @@ SYSCALL_DEFINE2(access, const char __user *, filename, int, mode)
 	return sys_faccessat(AT_FDCWD, filename, mode);
 }
 
-SYSCALL_DEFINE1(chdir, const char __user *, filename)
+int ksys_chdir(const char __user *filename)
 {
 	struct path path;
 	int error;
@@ -457,6 +457,11 @@ out:
 	return error;
 }
 
+SYSCALL_DEFINE1(chdir, const char __user *, filename)
+{
+	return ksys_chdir(filename);
+}
+
 SYSCALL_DEFINE1(fchdir, unsigned int, fd)
 {
 	struct fd f = fdget_raw(fd);
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 80524faa9664..090645b48447 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -952,5 +952,6 @@ int ksys_umount(char __user *name, int flags);
 int ksys_dup(unsigned int fildes);
 int ksys_chroot(const char __user *filename);
 ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count);
+int ksys_chdir(const char __user *filename);
 
 #endif
diff --git a/init/do_mounts.c b/init/do_mounts.c
index 2f06f7827b0c..89f18985fa90 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -367,7 +367,7 @@ static int __init do_mount_root(char *name, char *fs, int flags, void *data)
 	if (err)
 		return err;
 
-	sys_chdir("/root");
+	ksys_chdir("/root");
 	s = current->fs->pwd.dentry->d_sb;
 	ROOT_DEV = s->s_dev;
 	printk(KERN_INFO
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index 71293265ac4b..83f396d30b9a 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -42,7 +42,7 @@ static int init_linuxrc(struct subprocess_info *info, struct cred *new)
 	ksys_dup(0);
 	ksys_dup(0);
 	/* move initrd over / and chdir/chroot in initrd root */
-	sys_chdir("/root");
+	ksys_chdir("/root");
 	ksys_mount(".", "/", NULL, MS_MOVE, NULL);
 	ksys_chroot(".");
 	sys_setsid();
@@ -61,7 +61,7 @@ static void __init handle_initrd(void)
 	/* mount initrd on rootfs' /root */
 	mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY);
 	sys_mkdir("/old", 0700);
-	sys_chdir("/old");
+	ksys_chdir("/old");
 
 	/* try loading default modules from initrd */
 	load_default_modules();
@@ -86,11 +86,11 @@ static void __init handle_initrd(void)
 	ksys_chroot("..");
 
 	if (new_decode_dev(real_root_dev) == Root_RAM0) {
-		sys_chdir("/old");
+		ksys_chdir("/old");
 		return;
 	}
 
-	sys_chdir("/");
+	ksys_chdir("/");
 	ROOT_DEV = new_decode_dev(real_root_dev);
 	mount_root();
 
-- 
cgit v1.2.3


From 0f32ab8cfac478be053cb526ced8918ef6f4df47 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski
Date: Sun, 11 Mar 2018 11:34:47 +0100
Subject: fs: add ksys_unlink() wrapper; remove in-kernel calls to sys_unlink()

Using this wrapper allows us to avoid the in-kernel calls to the
sys_unlink() syscall. The ksys_ prefix denotes that this function is meant
s a drop-in replacement for the syscall. In particular, it uses the same
calling convention as sys_unlink().

In the near future, all callers of ksys_unlink() should be converted to
call do_unlinkat() directly or, at least, to operate on regular kernel
pointers.

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 include/linux/syscalls.h | 11 +++++++++++
 init/do_mounts.h         |  2 +-
 init/do_mounts_initrd.c  |  4 ++--
 init/do_mounts_rd.c      |  2 +-
 init/initramfs.c         |  4 ++--
 5 files changed, 17 insertions(+), 6 deletions(-)

(limited to 'init')

diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 090645b48447..7cbfb41e666b 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -954,4 +954,15 @@ int ksys_chroot(const char __user *filename);
 ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count);
 int ksys_chdir(const char __user *filename);
 
+/*
+ * The following kernel syscall equivalents are just wrappers to fs-internal
+ * functions. Therefore, provide stubs to be inlined at the callsites.
+ */
+extern long do_unlinkat(int dfd, struct filename *name);
+
+static inline long ksys_unlink(const char __user *pathname)
+{
+	return do_unlinkat(AT_FDCWD, getname(pathname));
+}
+
 #endif
diff --git a/init/do_mounts.h b/init/do_mounts.h
index 5b05c8f93f47..401f90ee1eeb 100644
--- a/init/do_mounts.h
+++ b/init/do_mounts.h
@@ -16,7 +16,7 @@ extern int root_mountflags;
 
 static inline int create_dev(char *name, dev_t dev)
 {
-	sys_unlink(name);
+	ksys_unlink(name);
 	return sys_mknod(name, S_IFBLK|0600, new_encode_dev(dev));
 }
 
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index 83f396d30b9a..e9e9e1c67d31 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -128,11 +128,11 @@ bool __init initrd_load(void)
 		 * mounted in the normal path.
 		 */
 		if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) {
-			sys_unlink("/initrd.image");
+			ksys_unlink("/initrd.image");
 			handle_initrd();
 			return true;
 		}
 	}
-	sys_unlink("/initrd.image");
+	ksys_unlink("/initrd.image");
 	return false;
 }
diff --git a/init/do_mounts_rd.c b/init/do_mounts_rd.c
index 2d365c398ccc..5b69056f610a 100644
--- a/init/do_mounts_rd.c
+++ b/init/do_mounts_rd.c
@@ -288,7 +288,7 @@ noclose_input:
 	sys_close(out_fd);
 out:
 	kfree(buf);
-	sys_unlink("/dev/ram");
+	ksys_unlink("/dev/ram");
 	return res;
 }
 
diff --git a/init/initramfs.c b/init/initramfs.c
index 6f972df15bf2..08eb551168a8 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -319,7 +319,7 @@ static void __init clean_path(char *path, umode_t fmode)
 		if (S_ISDIR(st.mode))
 			sys_rmdir(path);
 		else
-			sys_unlink(path);
+			ksys_unlink(path);
 	}
 }
 
@@ -591,7 +591,7 @@ static void __init clean_rootfs(void)
 				if (S_ISDIR(st.mode))
 					sys_rmdir(dirp->d_name);
 				else
-					sys_unlink(dirp->d_name);
+					ksys_unlink(dirp->d_name);
 			}
 
 			num -= dirp->d_reclen;
-- 
cgit v1.2.3


From f459dffae1c6026928bbe8e972daecb635b7b5e9 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski
Date: Sun, 11 Mar 2018 11:34:48 +0100
Subject: fs: add ksys_rmdir() wrapper; remove in-kernel calls to sys_rmdir()

Using this wrapper allows us to avoid the in-kernel calls to the
sys_rmdir() syscall. The ksys_ prefix denotes that this function is meant
as a drop-in replacement for the syscall. In particular, it uses the same
calling convention as sys_rmdir().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/internal.h            | 1 +
 fs/namei.c               | 2 +-
 include/linux/syscalls.h | 7 +++++++
 init/initramfs.c         | 4 ++--
 4 files changed, 11 insertions(+), 3 deletions(-)

(limited to 'init')

diff --git a/fs/internal.h b/fs/internal.h
index df262f41a0ef..0eda35fa1743 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -55,6 +55,7 @@ extern void __init chrdev_init(void);
 extern int user_path_mountpoint_at(int, const char __user *, unsigned int, struct path *);
 extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
 			   const char *, unsigned int, struct path *);
+long do_rmdir(int dfd, const char __user *pathname);
 long do_unlinkat(int dfd, struct filename *name);
 
 /*
diff --git a/fs/namei.c b/fs/namei.c
index 524e829ffc7d..8545151f74e9 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3872,7 +3872,7 @@ out:
 }
 EXPORT_SYMBOL(vfs_rmdir);
 
-static long do_rmdir(int dfd, const char __user *pathname)
+long do_rmdir(int dfd, const char __user *pathname)
 {
 	int error = 0;
 	struct filename *name;
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 7cbfb41e666b..746043a05884 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -965,4 +965,11 @@ static inline long ksys_unlink(const char __user *pathname)
 	return do_unlinkat(AT_FDCWD, getname(pathname));
 }
 
+extern long do_rmdir(int dfd, const char __user *pathname);
+
+static inline long ksys_rmdir(const char __user *pathname)
+{
+	return do_rmdir(AT_FDCWD, pathname);
+}
+
 #endif
diff --git a/init/initramfs.c b/init/initramfs.c
index 08eb551168a8..73bbb227f868 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -317,7 +317,7 @@ static void __init clean_path(char *path, umode_t fmode)
 
 	if (!vfs_lstat(path, &st) && (st.mode ^ fmode) & S_IFMT) {
 		if (S_ISDIR(st.mode))
-			sys_rmdir(path);
+			ksys_rmdir(path);
 		else
 			ksys_unlink(path);
 	}
@@ -589,7 +589,7 @@ static void __init clean_rootfs(void)
 			WARN_ON_ONCE(ret);
 			if (!ret) {
 				if (S_ISDIR(st.mode))
-					sys_rmdir(dirp->d_name);
+					ksys_rmdir(dirp->d_name);
 				else
 					ksys_unlink(dirp->d_name);
 			}
-- 
cgit v1.2.3


From 0101db7a301981a008296d522d8c1f456b0fe837 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski
Date: Sun, 11 Mar 2018 11:34:49 +0100
Subject: fs: add do_mkdirat() helper and ksys_mkdir() wrapper; remove
 in-kernel calls to syscall

Using the fs-internal do_mkdirat() helper allows us to get rid of
fs-internal calls to the sys_mkdirat() syscall.

Introducing the ksys_mkdir() wrapper allows us to avoid the in-kernel calls
to the sys_mkdir() syscall. The ksys_ prefix denotes that this function is
meant as a drop-in replacement for the syscall. In particular, it uses the
same calling convention as sys_mkdir().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/internal.h            | 1 +
 fs/namei.c               | 9 +++++++--
 include/linux/syscalls.h | 7 +++++++
 init/do_mounts_initrd.c  | 2 +-
 init/initramfs.c         | 2 +-
 init/noinitramfs.c       | 4 ++--
 6 files changed, 19 insertions(+), 6 deletions(-)

(limited to 'init')

diff --git a/fs/internal.h b/fs/internal.h
index 0eda35fa1743..53846bd4d9d7 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -55,6 +55,7 @@ extern void __init chrdev_init(void);
 extern int user_path_mountpoint_at(int, const char __user *, unsigned int, struct path *);
 extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
 			   const char *, unsigned int, struct path *);
+long do_mkdirat(int dfd, const char __user *pathname, umode_t mode);
 long do_rmdir(int dfd, const char __user *pathname);
 long do_unlinkat(int dfd, struct filename *name);
 
diff --git a/fs/namei.c b/fs/namei.c
index 8545151f74e9..dcf506227509 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3803,7 +3803,7 @@ int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 }
 EXPORT_SYMBOL(vfs_mkdir);
 
-SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode)
+long do_mkdirat(int dfd, const char __user *pathname, umode_t mode)
 {
 	struct dentry *dentry;
 	struct path path;
@@ -3828,9 +3828,14 @@ retry:
 	return error;
 }
 
+SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode)
+{
+	return do_mkdirat(dfd, pathname, mode);
+}
+
 SYSCALL_DEFINE2(mkdir, const char __user *, pathname, umode_t, mode)
 {
-	return sys_mkdirat(AT_FDCWD, pathname, mode);
+	return do_mkdirat(AT_FDCWD, pathname, mode);
 }
 
 int vfs_rmdir(struct inode *dir, struct dentry *dentry)
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 746043a05884..c982cb5f4e50 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -972,4 +972,11 @@ static inline long ksys_rmdir(const char __user *pathname)
 	return do_rmdir(AT_FDCWD, pathname);
 }
 
+extern long do_mkdirat(int dfd, const char __user *pathname, umode_t mode);
+
+static inline long ksys_mkdir(const char __user *pathname, umode_t mode)
+{
+	return do_mkdirat(AT_FDCWD, pathname, mode);
+}
+
 #endif
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index e9e9e1c67d31..99922d1ebfe6 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -60,7 +60,7 @@ static void __init handle_initrd(void)
 	create_dev("/dev/root.old", Root_RAM0);
 	/* mount initrd on rootfs' /root */
 	mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY);
-	sys_mkdir("/old", 0700);
+	ksys_mkdir("/old", 0700);
 	ksys_chdir("/old");
 
 	/* try loading default modules from initrd */
diff --git a/init/initramfs.c b/init/initramfs.c
index 73bbb227f868..ca538a5f9fa9 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -352,7 +352,7 @@ static int __init do_name(void)
 			}
 		}
 	} else if (S_ISDIR(mode)) {
-		sys_mkdir(collected, mode);
+		ksys_mkdir(collected, mode);
 		sys_chown(collected, uid, gid);
 		sys_chmod(collected, mode);
 		dir_add(collected, mtime);
diff --git a/init/noinitramfs.c b/init/noinitramfs.c
index 267739d85179..a08a9d937e60 100644
--- a/init/noinitramfs.c
+++ b/init/noinitramfs.c
@@ -29,7 +29,7 @@ static int __init default_rootfs(void)
 {
 	int err;
 
-	err = sys_mkdir((const char __user __force *) "/dev", 0755);
+	err = ksys_mkdir((const char __user __force *) "/dev", 0755);
 	if (err < 0)
 		goto out;
 
@@ -39,7 +39,7 @@ static int __init default_rootfs(void)
 	if (err < 0)
 		goto out;
 
-	err = sys_mkdir((const char __user __force *) "/root", 0700);
+	err = ksys_mkdir((const char __user __force *) "/root", 0700);
 	if (err < 0)
 		goto out;
 
-- 
cgit v1.2.3


From b724e846b491ef8db943be8086226c9d8da31877 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski
Date: Sun, 11 Mar 2018 11:34:49 +0100
Subject: fs: add do_symlinkat() helper and ksys_symlink() wrapper; remove
 in-kernel calls to syscall

Using the fs-internal do_symlinkat() helper allows us to get rid of
fs-internal calls to the sys_symlinkat() syscall.

Introducing the ksys_symlink() wrapper allows us to avoid the in-kernel
calls to the sys_symlink() syscall. The ksys_ prefix denotes that this
function is meant as a drop-in replacement for the syscall. In particular,
it uses the same calling convention as sys_symlink().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/internal.h            |  2 ++
 fs/namei.c               | 12 +++++++++---
 include/linux/syscalls.h |  9 +++++++++
 init/initramfs.c         |  2 +-
 4 files changed, 21 insertions(+), 4 deletions(-)

(limited to 'init')

diff --git a/fs/internal.h b/fs/internal.h
index 53846bd4d9d7..a3f04ca2a08b 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -58,6 +58,8 @@ extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
 long do_mkdirat(int dfd, const char __user *pathname, umode_t mode);
 long do_rmdir(int dfd, const char __user *pathname);
 long do_unlinkat(int dfd, struct filename *name);
+long do_symlinkat(const char __user *oldname, int newdfd,
+		  const char __user *newname);
 
 /*
  * namespace.c
diff --git a/fs/namei.c b/fs/namei.c
index dcf506227509..e15da92209d5 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -4113,8 +4113,8 @@ int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)
 }
 EXPORT_SYMBOL(vfs_symlink);
 
-SYSCALL_DEFINE3(symlinkat, const char __user *, oldname,
-		int, newdfd, const char __user *, newname)
+long do_symlinkat(const char __user *oldname, int newdfd,
+		  const char __user *newname)
 {
 	int error;
 	struct filename *from;
@@ -4144,9 +4144,15 @@ out_putname:
 	return error;
 }
 
+SYSCALL_DEFINE3(symlinkat, const char __user *, oldname,
+		int, newdfd, const char __user *, newname)
+{
+	return do_symlinkat(oldname, newdfd, newname);
+}
+
 SYSCALL_DEFINE2(symlink, const char __user *, oldname, const char __user *, newname)
 {
-	return sys_symlinkat(oldname, AT_FDCWD, newname);
+	return do_symlinkat(oldname, AT_FDCWD, newname);
 }
 
 /**
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index c982cb5f4e50..39c5cef86a10 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -979,4 +979,13 @@ static inline long ksys_mkdir(const char __user *pathname, umode_t mode)
 	return do_mkdirat(AT_FDCWD, pathname, mode);
 }
 
+extern long do_symlinkat(const char __user *oldname, int newdfd,
+			 const char __user *newname);
+
+static inline long ksys_symlink(const char __user *oldname,
+				const char __user *newname)
+{
+	return do_symlinkat(oldname, AT_FDCWD, newname);
+}
+
 #endif
diff --git a/init/initramfs.c b/init/initramfs.c
index ca538a5f9fa9..cd9571a113b6 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -392,7 +392,7 @@ static int __init do_symlink(void)
 {
 	collected[N_ALIGN(name_len) + body_len] = '\0';
 	clean_path(collected, 0);
-	sys_symlink(collected + N_ALIGN(name_len), collected);
+	ksys_symlink(collected + N_ALIGN(name_len), collected);
 	sys_lchown(collected, uid, gid);
 	do_utime(collected, mtime);
 	state = SkipIt;
-- 
cgit v1.2.3


From 87c4e19262d81862886207be3c8795f6576d5a52 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski
Date: Sun, 11 Mar 2018 11:34:50 +0100
Subject: fs: add do_mknodat() helper and ksys_mknod() wrapper; remove
 in-kernel calls to syscall

Using the fs-internal do_mknodat() helper allows us to get rid of
fs-internal calls to the sys_mknodat() syscall.

Introducing the ksys_mknod() wrapper allows us to avoid the in-kernel
calls to sys_mknod() syscall. The ksys_ prefix denotes that this function
is meant as a drop-in replacement for the syscall. In particular, it uses
the same calling convention as sys_mknod().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/internal.h            |  2 ++
 fs/namei.c               | 12 +++++++++---
 include/linux/syscalls.h |  9 +++++++++
 init/do_mounts.h         |  2 +-
 init/initramfs.c         |  2 +-
 init/noinitramfs.c       |  2 +-
 6 files changed, 23 insertions(+), 6 deletions(-)

(limited to 'init')

diff --git a/fs/internal.h b/fs/internal.h
index a3f04ca2a08b..4f0b67054c54 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -55,6 +55,8 @@ extern void __init chrdev_init(void);
 extern int user_path_mountpoint_at(int, const char __user *, unsigned int, struct path *);
 extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
 			   const char *, unsigned int, struct path *);
+long do_mknodat(int dfd, const char __user *filename, umode_t mode,
+		unsigned int dev);
 long do_mkdirat(int dfd, const char __user *pathname, umode_t mode);
 long do_rmdir(int dfd, const char __user *pathname);
 long do_unlinkat(int dfd, struct filename *name);
diff --git a/fs/namei.c b/fs/namei.c
index e15da92209d5..8459a18cdd18 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3728,8 +3728,8 @@ static int may_mknod(umode_t mode)
 	}
 }
 
-SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode,
-		unsigned, dev)
+long do_mknodat(int dfd, const char __user *filename, umode_t mode,
+		unsigned int dev)
 {
 	struct dentry *dentry;
 	struct path path;
@@ -3772,9 +3772,15 @@ out:
 	return error;
 }
 
+SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode,
+		unsigned int, dev)
+{
+	return do_mknodat(dfd, filename, mode, dev);
+}
+
 SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, dev)
 {
-	return sys_mknodat(AT_FDCWD, filename, mode, dev);
+	return do_mknodat(AT_FDCWD, filename, mode, dev);
 }
 
 int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 39c5cef86a10..0b4fd684f0f1 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -988,4 +988,13 @@ static inline long ksys_symlink(const char __user *oldname,
 	return do_symlinkat(oldname, AT_FDCWD, newname);
 }
 
+extern long do_mknodat(int dfd, const char __user *filename, umode_t mode,
+		       unsigned int dev);
+
+static inline long ksys_mknod(const char __user *filename, umode_t mode,
+			      unsigned int dev)
+{
+	return do_mknodat(AT_FDCWD, filename, mode, dev);
+}
+
 #endif
diff --git a/init/do_mounts.h b/init/do_mounts.h
index 401f90ee1eeb..0bb0806de4ce 100644
--- a/init/do_mounts.h
+++ b/init/do_mounts.h
@@ -17,7 +17,7 @@ extern int root_mountflags;
 static inline int create_dev(char *name, dev_t dev)
 {
 	ksys_unlink(name);
-	return sys_mknod(name, S_IFBLK|0600, new_encode_dev(dev));
+	return ksys_mknod(name, S_IFBLK|0600, new_encode_dev(dev));
 }
 
 static inline u32 bstat(char *name)
diff --git a/init/initramfs.c b/init/initramfs.c
index cd9571a113b6..2972ed0ab399 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -359,7 +359,7 @@ static int __init do_name(void)
 	} else if (S_ISBLK(mode) || S_ISCHR(mode) ||
 		   S_ISFIFO(mode) || S_ISSOCK(mode)) {
 		if (maybe_link() == 0) {
-			sys_mknod(collected, mode, rdev);
+			ksys_mknod(collected, mode, rdev);
 			sys_chown(collected, uid, gid);
 			sys_chmod(collected, mode);
 			do_utime(collected, mtime);
diff --git a/init/noinitramfs.c b/init/noinitramfs.c
index a08a9d937e60..f4bad8436c93 100644
--- a/init/noinitramfs.c
+++ b/init/noinitramfs.c
@@ -33,7 +33,7 @@ static int __init default_rootfs(void)
 	if (err < 0)
 		goto out;
 
-	err = sys_mknod((const char __user __force *) "/dev/console",
+	err = ksys_mknod((const char __user __force *) "/dev/console",
 			S_IFCHR | S_IRUSR | S_IWUSR,
 			new_encode_dev(MKDEV(5, 1)));
 	if (err < 0)
-- 
cgit v1.2.3


From 46ea89eb652a365e10257016d09dcf1aaf23cf63 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski
Date: Sun, 11 Mar 2018 11:34:53 +0100
Subject: fs: add do_linkat() helper and ksys_link() wrapper; remove in-kernel
 calls to syscall

Using the fs-internal do_linkat() helper allows us to get rid of
fs-internal calls to the sys_linkat() syscall.

Introducing the ksys_link() wrapper allows us to avoid the in-kernel
calls to sys_link() syscall. The ksys_ prefix denotes that this function
is meant as a drop-in replacement for the syscall. In particular, it uses
the same calling convention as sys_link().

In the near future, the only fs-external user of ksys_link() should be
converted to use vfs_link() instead.

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/internal.h            |  2 ++
 fs/namei.c               | 12 +++++++++---
 include/linux/syscalls.h |  9 +++++++++
 init/initramfs.c         |  2 +-
 4 files changed, 21 insertions(+), 4 deletions(-)

(limited to 'init')

diff --git a/fs/internal.h b/fs/internal.h
index 4f0b67054c54..91e6fc93fcb5 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -62,6 +62,8 @@ long do_rmdir(int dfd, const char __user *pathname);
 long do_unlinkat(int dfd, struct filename *name);
 long do_symlinkat(const char __user *oldname, int newdfd,
 		  const char __user *newname);
+int do_linkat(int olddfd, const char __user *oldname, int newdfd,
+	      const char __user *newname, int flags);
 
 /*
  * namespace.c
diff --git a/fs/namei.c b/fs/namei.c
index 8459a18cdd18..10148235829f 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -4250,8 +4250,8 @@ EXPORT_SYMBOL(vfs_link);
  * with linux 2.0, and to avoid hard-linking to directories
  * and other special files.  --ADM
  */
-SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
-		int, newdfd, const char __user *, newname, int, flags)
+int do_linkat(int olddfd, const char __user *oldname, int newdfd,
+	      const char __user *newname, int flags)
 {
 	struct dentry *new_dentry;
 	struct path old_path, new_path;
@@ -4315,9 +4315,15 @@ out:
 	return error;
 }
 
+SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
+		int, newdfd, const char __user *, newname, int, flags)
+{
+	return do_linkat(olddfd, oldname, newdfd, newname, flags);
+}
+
 SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname)
 {
-	return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
+	return do_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
 }
 
 /**
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 0b4fd684f0f1..827ed917630c 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -997,4 +997,13 @@ static inline long ksys_mknod(const char __user *filename, umode_t mode,
 	return do_mknodat(AT_FDCWD, filename, mode, dev);
 }
 
+extern int do_linkat(int olddfd, const char __user *oldname, int newdfd,
+		     const char __user *newname, int flags);
+
+static inline long ksys_link(const char __user *oldname,
+			     const char __user *newname)
+{
+	return do_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
+}
+
 #endif
diff --git a/init/initramfs.c b/init/initramfs.c
index 2972ed0ab399..5855ab632b4e 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -306,7 +306,7 @@ static int __init maybe_link(void)
 	if (nlink >= 2) {
 		char *old = find_link(major, minor, ino, mode, collected);
 		if (old)
-			return (sys_link(old, collected) < 0) ? -1 : 1;
+			return (ksys_link(old, collected) < 0) ? -1 : 1;
 	}
 	return 0;
 }
-- 
cgit v1.2.3


From 03450e271a160bc07a2c48e5769e0ba338582d77 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski
Date: Sun, 11 Mar 2018 11:34:53 +0100
Subject: fs: add ksys_fchmod() and do_fchmodat() helpers and ksys_chmod()
 wrapper; remove in-kernel calls to syscall

Using the fs-internal do_fchmodat() helper allows us to get rid of
fs-internal calls to the sys_fchmodat() syscall.

Introducing the ksys_fchmod() helper and the ksys_chmod() wrapper allows
us to avoid the in-kernel calls to the sys_fchmod() and sys_chmod()
syscalls. The ksys_ prefix denotes that these functions are meant as a
drop-in replacement for the syscalls. In particular, they use the same
calling convention as sys_fchmod() and sys_chmod().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/internal.h            |  2 ++
 fs/open.c                | 17 ++++++++++++++---
 include/linux/syscalls.h |  8 ++++++++
 init/initramfs.c         |  6 +++---
 4 files changed, 27 insertions(+), 6 deletions(-)

(limited to 'init')

diff --git a/fs/internal.h b/fs/internal.h
index 91e6fc93fcb5..2474bf460f96 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -119,6 +119,8 @@ extern struct file *do_filp_open(int dfd, struct filename *pathname,
 extern struct file *do_file_open_root(struct dentry *, struct vfsmount *,
 		const char *, const struct open_flags *);
 
+int do_fchmodat(int dfd, const char __user *filename, umode_t mode);
+
 extern int open_check_o_direct(struct file *f);
 extern int vfs_open(const struct path *, struct file *, const struct cred *);
 extern struct file *filp_clone_open(struct file *);
diff --git a/fs/open.c b/fs/open.c
index a19b8277c439..6037f2bf418c 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -551,7 +551,7 @@ out_unlock:
 	return error;
 }
 
-SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode)
+int ksys_fchmod(unsigned int fd, umode_t mode)
 {
 	struct fd f = fdget(fd);
 	int err = -EBADF;
@@ -564,7 +564,12 @@ SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode)
 	return err;
 }
 
-SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, umode_t, mode)
+SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode)
+{
+	return ksys_fchmod(fd, mode);
+}
+
+int do_fchmodat(int dfd, const char __user *filename, umode_t mode)
 {
 	struct path path;
 	int error;
@@ -582,9 +587,15 @@ retry:
 	return error;
 }
 
+SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename,
+		umode_t, mode)
+{
+	return do_fchmodat(dfd, filename, mode);
+}
+
 SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode)
 {
-	return sys_fchmodat(AT_FDCWD, filename, mode);
+	return do_fchmodat(AT_FDCWD, filename, mode);
 }
 
 static int chown_common(const struct path *path, uid_t user, gid_t group)
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 827ed917630c..dd6c306f4f00 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -953,6 +953,7 @@ int ksys_dup(unsigned int fildes);
 int ksys_chroot(const char __user *filename);
 ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count);
 int ksys_chdir(const char __user *filename);
+int ksys_fchmod(unsigned int fd, umode_t mode);
 
 /*
  * The following kernel syscall equivalents are just wrappers to fs-internal
@@ -1006,4 +1007,11 @@ static inline long ksys_link(const char __user *oldname,
 	return do_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
 }
 
+extern int do_fchmodat(int dfd, const char __user *filename, umode_t mode);
+
+static inline int ksys_chmod(const char __user *filename, umode_t mode)
+{
+	return do_fchmodat(AT_FDCWD, filename, mode);
+}
+
 #endif
diff --git a/init/initramfs.c b/init/initramfs.c
index 5855ab632b4e..16c3c23076e2 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -344,7 +344,7 @@ static int __init do_name(void)
 
 			if (wfd >= 0) {
 				sys_fchown(wfd, uid, gid);
-				sys_fchmod(wfd, mode);
+				ksys_fchmod(wfd, mode);
 				if (body_len)
 					sys_ftruncate(wfd, body_len);
 				vcollected = kstrdup(collected, GFP_KERNEL);
@@ -354,14 +354,14 @@ static int __init do_name(void)
 	} else if (S_ISDIR(mode)) {
 		ksys_mkdir(collected, mode);
 		sys_chown(collected, uid, gid);
-		sys_chmod(collected, mode);
+		ksys_chmod(collected, mode);
 		dir_add(collected, mtime);
 	} else if (S_ISBLK(mode) || S_ISCHR(mode) ||
 		   S_ISFIFO(mode) || S_ISSOCK(mode)) {
 		if (maybe_link() == 0) {
 			ksys_mknod(collected, mode, rdev);
 			sys_chown(collected, uid, gid);
-			sys_chmod(collected, mode);
+			ksys_chmod(collected, mode);
 			do_utime(collected, mtime);
 		}
 	}
-- 
cgit v1.2.3


From cbfe20f565228966f0249f016752437df95df679 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski
Date: Sun, 11 Mar 2018 11:34:54 +0100
Subject: fs: add do_faccessat() helper and ksys_access() wrapper; remove
 in-kernel calls to syscall

Using the fs-internal do_faccessat() helper allows us to get rid of
fs-internal calls to the sys_faccessat() syscall.

Introducing the ksys_access() wrapper allows us to avoid the in-kernel
calls to the sys_access() syscall. The ksys_ prefix denotes that this
function is meant as a drop-in replacement for the syscall. In
particular, it uses the same calling convention as sys_access().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/internal.h            | 1 +
 fs/open.c                | 9 +++++++--
 include/linux/syscalls.h | 7 +++++++
 init/main.c              | 3 ++-
 4 files changed, 17 insertions(+), 3 deletions(-)

(limited to 'init')

diff --git a/fs/internal.h b/fs/internal.h
index 2474bf460f96..26f4f05b52ef 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -119,6 +119,7 @@ extern struct file *do_filp_open(int dfd, struct filename *pathname,
 extern struct file *do_file_open_root(struct dentry *, struct vfsmount *,
 		const char *, const struct open_flags *);
 
+long do_faccessat(int dfd, const char __user *filename, int mode);
 int do_fchmodat(int dfd, const char __user *filename, umode_t mode);
 
 extern int open_check_o_direct(struct file *f);
diff --git a/fs/open.c b/fs/open.c
index 6037f2bf418c..0fc8188be31a 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -350,7 +350,7 @@ SYSCALL_DEFINE4(fallocate, int, fd, int, mode, loff_t, offset, loff_t, len)
  * We do this by temporarily clearing all FS-related capabilities and
  * switching the fsuid/fsgid around to the real ones.
  */
-SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
+long do_faccessat(int dfd, const char __user *filename, int mode)
 {
 	const struct cred *old_cred;
 	struct cred *override_cred;
@@ -426,9 +426,14 @@ out:
 	return res;
 }
 
+SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
+{
+	return do_faccessat(dfd, filename, mode);
+}
+
 SYSCALL_DEFINE2(access, const char __user *, filename, int, mode)
 {
-	return sys_faccessat(AT_FDCWD, filename, mode);
+	return do_faccessat(AT_FDCWD, filename, mode);
 }
 
 int ksys_chdir(const char __user *filename)
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index dd6c306f4f00..33f06de090ea 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1014,4 +1014,11 @@ static inline int ksys_chmod(const char __user *filename, umode_t mode)
 	return do_fchmodat(AT_FDCWD, filename, mode);
 }
 
+extern long do_faccessat(int dfd, const char __user *filename, int mode);
+
+static inline long ksys_access(const char __user *filename, int mode)
+{
+	return do_faccessat(AT_FDCWD, filename, mode);
+}
+
 #endif
diff --git a/init/main.c b/init/main.c
index b8649d1466e1..d0ded4322c6b 100644
--- a/init/main.c
+++ b/init/main.c
@@ -1087,7 +1087,8 @@ static noinline void __init kernel_init_freeable(void)
 	if (!ramdisk_execute_command)
 		ramdisk_execute_command = "/init";
 
-	if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
+	if (ksys_access((const char __user *)
+			ramdisk_execute_command, 0) != 0) {
 		ramdisk_execute_command = NULL;
 		prepare_namespace();
 	}
-- 
cgit v1.2.3


From 55731b3cda3a85ee888dac3bf1f36489f275c187 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski
Date: Sun, 11 Mar 2018 11:34:55 +0100
Subject: fs: add do_fchownat(), ksys_fchown() helpers and ksys_{,l}chown()
 wrappers

Using the fs-interal do_fchownat() wrapper allows us to get rid of
fs-internal calls to the sys_fchownat() syscall.

Introducing the ksys_fchown() helper and the ksys_{,}chown() wrappers
allows us to avoid the in-kernel calls to the sys_{,l,f}chown() syscalls.
The ksys_ prefix denotes that these functions are meant as a drop-in
replacement for the syscalls. In particular, they use the same calling
convention as sys_{,l,f}chown().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 arch/s390/kernel/compat_linux.c |  6 +++---
 fs/internal.h                   |  2 ++
 fs/open.c                       | 23 +++++++++++++++++------
 include/linux/syscalls.h        | 17 +++++++++++++++++
 init/initramfs.c                |  8 ++++----
 kernel/uid16.c                  |  6 +++---
 6 files changed, 46 insertions(+), 16 deletions(-)

(limited to 'init')

diff --git a/arch/s390/kernel/compat_linux.c b/arch/s390/kernel/compat_linux.c
index 5a9cfde5fc28..9a9bb395359c 100644
--- a/arch/s390/kernel/compat_linux.c
+++ b/arch/s390/kernel/compat_linux.c
@@ -89,18 +89,18 @@
 COMPAT_SYSCALL_DEFINE3(s390_chown16, const char __user *, filename,
 		       u16, user, u16, group)
 {
-	return sys_chown(filename, low2highuid(user), low2highgid(group));
+	return ksys_chown(filename, low2highuid(user), low2highgid(group));
 }
 
 COMPAT_SYSCALL_DEFINE3(s390_lchown16, const char __user *,
 		       filename, u16, user, u16, group)
 {
-	return sys_lchown(filename, low2highuid(user), low2highgid(group));
+	return ksys_lchown(filename, low2highuid(user), low2highgid(group));
 }
 
 COMPAT_SYSCALL_DEFINE3(s390_fchown16, unsigned int, fd, u16, user, u16, group)
 {
-	return sys_fchown(fd, low2highuid(user), low2highgid(group));
+	return ksys_fchown(fd, low2highuid(user), low2highgid(group));
 }
 
 COMPAT_SYSCALL_DEFINE2(s390_setregid16, u16, rgid, u16, egid)
diff --git a/fs/internal.h b/fs/internal.h
index 26f4f05b52ef..c797480cbd6f 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -121,6 +121,8 @@ extern struct file *do_file_open_root(struct dentry *, struct vfsmount *,
 
 long do_faccessat(int dfd, const char __user *filename, int mode);
 int do_fchmodat(int dfd, const char __user *filename, umode_t mode);
+int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,
+		int flag);
 
 extern int open_check_o_direct(struct file *f);
 extern int vfs_open(const struct path *, struct file *, const struct cred *);
diff --git a/fs/open.c b/fs/open.c
index 0fc8188be31a..7b2eccb541f2 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -645,8 +645,8 @@ retry_deleg:
 	return error;
 }
 
-SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
-		gid_t, group, int, flag)
+int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,
+		int flag)
 {
 	struct path path;
 	int error = -EINVAL;
@@ -677,18 +677,24 @@ out:
 	return error;
 }
 
+SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
+		gid_t, group, int, flag)
+{
+	return do_fchownat(dfd, filename, user, group, flag);
+}
+
 SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
 {
-	return sys_fchownat(AT_FDCWD, filename, user, group, 0);
+	return do_fchownat(AT_FDCWD, filename, user, group, 0);
 }
 
 SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group)
 {
-	return sys_fchownat(AT_FDCWD, filename, user, group,
-			    AT_SYMLINK_NOFOLLOW);
+	return do_fchownat(AT_FDCWD, filename, user, group,
+			   AT_SYMLINK_NOFOLLOW);
 }
 
-SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
+int ksys_fchown(unsigned int fd, uid_t user, gid_t group)
 {
 	struct fd f = fdget(fd);
 	int error = -EBADF;
@@ -708,6 +714,11 @@ out:
 	return error;
 }
 
+SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
+{
+	return ksys_fchown(fd, user, group);
+}
+
 int open_check_o_direct(struct file *f)
 {
 	/* NB: we're sure to have correct a_ops only after f_op->open */
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 33f06de090ea..df0d1e818a6e 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -954,6 +954,7 @@ int ksys_chroot(const char __user *filename);
 ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count);
 int ksys_chdir(const char __user *filename);
 int ksys_fchmod(unsigned int fd, umode_t mode);
+int ksys_fchown(unsigned int fd, uid_t user, gid_t group);
 
 /*
  * The following kernel syscall equivalents are just wrappers to fs-internal
@@ -1021,4 +1022,20 @@ static inline long ksys_access(const char __user *filename, int mode)
 	return do_faccessat(AT_FDCWD, filename, mode);
 }
 
+extern int do_fchownat(int dfd, const char __user *filename, uid_t user,
+		       gid_t group, int flag);
+
+static inline long ksys_chown(const char __user *filename, uid_t user,
+			      gid_t group)
+{
+	return do_fchownat(AT_FDCWD, filename, user, group, 0);
+}
+
+static inline long ksys_lchown(const char __user *filename, uid_t user,
+			       gid_t group)
+{
+	return do_fchownat(AT_FDCWD, filename, user, group,
+			     AT_SYMLINK_NOFOLLOW);
+}
+
 #endif
diff --git a/init/initramfs.c b/init/initramfs.c
index 16c3c23076e2..35173bef7c00 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -343,7 +343,7 @@ static int __init do_name(void)
 			wfd = sys_open(collected, openflags, mode);
 
 			if (wfd >= 0) {
-				sys_fchown(wfd, uid, gid);
+				ksys_fchown(wfd, uid, gid);
 				ksys_fchmod(wfd, mode);
 				if (body_len)
 					sys_ftruncate(wfd, body_len);
@@ -353,14 +353,14 @@ static int __init do_name(void)
 		}
 	} else if (S_ISDIR(mode)) {
 		ksys_mkdir(collected, mode);
-		sys_chown(collected, uid, gid);
+		ksys_chown(collected, uid, gid);
 		ksys_chmod(collected, mode);
 		dir_add(collected, mtime);
 	} else if (S_ISBLK(mode) || S_ISCHR(mode) ||
 		   S_ISFIFO(mode) || S_ISSOCK(mode)) {
 		if (maybe_link() == 0) {
 			ksys_mknod(collected, mode, rdev);
-			sys_chown(collected, uid, gid);
+			ksys_chown(collected, uid, gid);
 			ksys_chmod(collected, mode);
 			do_utime(collected, mtime);
 		}
@@ -393,7 +393,7 @@ static int __init do_symlink(void)
 	collected[N_ALIGN(name_len) + body_len] = '\0';
 	clean_path(collected, 0);
 	ksys_symlink(collected + N_ALIGN(name_len), collected);
-	sys_lchown(collected, uid, gid);
+	ksys_lchown(collected, uid, gid);
 	do_utime(collected, mtime);
 	state = SkipIt;
 	next_state = Reset;
diff --git a/kernel/uid16.c b/kernel/uid16.c
index 7b930edfe461..af6925d8599b 100644
--- a/kernel/uid16.c
+++ b/kernel/uid16.c
@@ -22,17 +22,17 @@
 
 SYSCALL_DEFINE3(chown16, const char __user *, filename, old_uid_t, user, old_gid_t, group)
 {
-	return sys_chown(filename, low2highuid(user), low2highgid(group));
+	return ksys_chown(filename, low2highuid(user), low2highgid(group));
 }
 
 SYSCALL_DEFINE3(lchown16, const char __user *, filename, old_uid_t, user, old_gid_t, group)
 {
-	return sys_lchown(filename, low2highuid(user), low2highgid(group));
+	return ksys_lchown(filename, low2highuid(user), low2highgid(group));
 }
 
 SYSCALL_DEFINE3(fchown16, unsigned int, fd, old_uid_t, user, old_gid_t, group)
 {
-	return sys_fchown(fd, low2highuid(user), low2highgid(group));
+	return ksys_fchown(fd, low2highuid(user), low2highgid(group));
 }
 
 SYSCALL_DEFINE2(setregid16, old_gid_t, rgid, old_gid_t, egid)
-- 
cgit v1.2.3


From 411d9475cf901b5a6d2996b46cb5726184a4fa50 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski
Date: Sun, 11 Mar 2018 11:34:54 +0100
Subject: fs: add ksys_ftruncate() wrapper; remove in-kernel calls to
 sys_ftruncate()

Using the ksys_ftruncate() wrapper allows us to get rid of in-kernel
calls to the sys_ftruncate() syscall. The ksys_ prefix denotes that this
function is meant as a drop-in replacement for the syscall. In
particular, it uses the same calling convention as sys_ftruncate().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 arch/mips/kernel/linux32.c      | 2 +-
 arch/parisc/kernel/sys_parisc.c | 4 ++--
 arch/powerpc/kernel/sys_ppc32.c | 2 +-
 arch/s390/kernel/compat_linux.c | 2 +-
 arch/sparc/kernel/sys_sparc32.c | 2 +-
 arch/x86/ia32/sys_ia32.c        | 2 +-
 fs/internal.h                   | 1 +
 fs/open.c                       | 2 +-
 include/linux/syscalls.h        | 7 +++++++
 init/initramfs.c                | 2 +-
 10 files changed, 17 insertions(+), 9 deletions(-)

(limited to 'init')

diff --git a/arch/mips/kernel/linux32.c b/arch/mips/kernel/linux32.c
index b332f6fc1e72..3c90449742a0 100644
--- a/arch/mips/kernel/linux32.c
+++ b/arch/mips/kernel/linux32.c
@@ -88,7 +88,7 @@ SYSCALL_DEFINE4(32_truncate64, const char __user *, path,
 SYSCALL_DEFINE4(32_ftruncate64, unsigned long, fd, unsigned long, __dummy,
 	unsigned long, a2, unsigned long, a3)
 {
-	return sys_ftruncate(fd, merge_64(a2, a3));
+	return ksys_ftruncate(fd, merge_64(a2, a3));
 }
 
 SYSCALL_DEFINE5(32_llseek, unsigned int, fd, unsigned int, offset_high,
diff --git a/arch/parisc/kernel/sys_parisc.c b/arch/parisc/kernel/sys_parisc.c
index 378a754ca186..6d2a64859c22 100644
--- a/arch/parisc/kernel/sys_parisc.c
+++ b/arch/parisc/kernel/sys_parisc.c
@@ -298,7 +298,7 @@ asmlinkage long parisc_truncate64(const char __user * path,
 asmlinkage long parisc_ftruncate64(unsigned int fd,
 					unsigned int high, unsigned int low)
 {
-	return sys_ftruncate(fd, (long)high << 32 | low);
+	return ksys_ftruncate(fd, (long)high << 32 | low);
 }
 
 /* stubs for the benefit of the syscall_table since truncate64 and truncate 
@@ -309,7 +309,7 @@ asmlinkage long sys_truncate64(const char __user * path, unsigned long length)
 }
 asmlinkage long sys_ftruncate64(unsigned int fd, unsigned long length)
 {
-	return sys_ftruncate(fd, length);
+	return ksys_ftruncate(fd, length);
 }
 asmlinkage long sys_fcntl64(unsigned int fd, unsigned int cmd, unsigned long arg)
 {
diff --git a/arch/powerpc/kernel/sys_ppc32.c b/arch/powerpc/kernel/sys_ppc32.c
index 15f216d022e2..e0c9b7f1bf38 100644
--- a/arch/powerpc/kernel/sys_ppc32.c
+++ b/arch/powerpc/kernel/sys_ppc32.c
@@ -107,7 +107,7 @@ asmlinkage long compat_sys_fallocate(int fd, int mode, u32 offhi, u32 offlo,
 asmlinkage int compat_sys_ftruncate64(unsigned int fd, u32 reg4, unsigned long high,
 				 unsigned long low)
 {
-	return sys_ftruncate(fd, (high << 32) | low);
+	return ksys_ftruncate(fd, (high << 32) | low);
 }
 
 long ppc32_fadvise64(int fd, u32 unused, u32 offset_high, u32 offset_low,
diff --git a/arch/s390/kernel/compat_linux.c b/arch/s390/kernel/compat_linux.c
index 9a9bb395359c..9c5e975f71a6 100644
--- a/arch/s390/kernel/compat_linux.c
+++ b/arch/s390/kernel/compat_linux.c
@@ -307,7 +307,7 @@ COMPAT_SYSCALL_DEFINE3(s390_truncate64, const char __user *, path, u32, high, u3
 
 COMPAT_SYSCALL_DEFINE3(s390_ftruncate64, unsigned int, fd, u32, high, u32, low)
 {
-	return sys_ftruncate(fd, (unsigned long)high << 32 | low);
+	return ksys_ftruncate(fd, (unsigned long)high << 32 | low);
 }
 
 COMPAT_SYSCALL_DEFINE5(s390_pread64, unsigned int, fd, char __user *, ubuf,
diff --git a/arch/sparc/kernel/sys_sparc32.c b/arch/sparc/kernel/sys_sparc32.c
index 6d964bdefbaa..d64b425fff93 100644
--- a/arch/sparc/kernel/sys_sparc32.c
+++ b/arch/sparc/kernel/sys_sparc32.c
@@ -65,7 +65,7 @@ asmlinkage long sys32_ftruncate64(unsigned int fd, unsigned long high, unsigned
 	if ((int)high < 0)
 		return -EINVAL;
 	else
-		return sys_ftruncate(fd, (high << 32) | low);
+		return ksys_ftruncate(fd, (high << 32) | low);
 }
 
 static int cp_compat_stat64(struct kstat *stat,
diff --git a/arch/x86/ia32/sys_ia32.c b/arch/x86/ia32/sys_ia32.c
index 23a5260eae67..1979e5b4ad9a 100644
--- a/arch/x86/ia32/sys_ia32.c
+++ b/arch/x86/ia32/sys_ia32.c
@@ -61,7 +61,7 @@ COMPAT_SYSCALL_DEFINE3(x86_truncate64, const char __user *, filename,
 COMPAT_SYSCALL_DEFINE3(x86_ftruncate64, unsigned int, fd,
 		       unsigned long, offset_low, unsigned long, offset_high)
 {
-       return sys_ftruncate(fd, ((loff_t) offset_high << 32) | offset_low);
+	return ksys_ftruncate(fd, ((loff_t) offset_high << 32) | offset_low);
 }
 
 /*
diff --git a/fs/internal.h b/fs/internal.h
index c797480cbd6f..980d005b21b4 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -119,6 +119,7 @@ extern struct file *do_filp_open(int dfd, struct filename *pathname,
 extern struct file *do_file_open_root(struct dentry *, struct vfsmount *,
 		const char *, const struct open_flags *);
 
+long do_sys_ftruncate(unsigned int fd, loff_t length, int small);
 long do_faccessat(int dfd, const char __user *filename, int mode);
 int do_fchmodat(int dfd, const char __user *filename, umode_t mode);
 int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,
diff --git a/fs/open.c b/fs/open.c
index 7b2eccb541f2..b3f3b2cd9f19 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -162,7 +162,7 @@ COMPAT_SYSCALL_DEFINE2(truncate, const char __user *, path, compat_off_t, length
 }
 #endif
 
-static long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
+long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
 {
 	struct inode *inode;
 	struct dentry *dentry;
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index df0d1e818a6e..41023177c8ec 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1038,4 +1038,11 @@ static inline long ksys_lchown(const char __user *filename, uid_t user,
 			     AT_SYMLINK_NOFOLLOW);
 }
 
+extern long do_sys_ftruncate(unsigned int fd, loff_t length, int small);
+
+static inline long ksys_ftruncate(unsigned int fd, unsigned long length)
+{
+	return do_sys_ftruncate(fd, length, 1);
+}
+
 #endif
diff --git a/init/initramfs.c b/init/initramfs.c
index 35173bef7c00..0d3b001b0dc5 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -346,7 +346,7 @@ static int __init do_name(void)
 				ksys_fchown(wfd, uid, gid);
 				ksys_fchmod(wfd, mode);
 				if (body_len)
-					sys_ftruncate(wfd, body_len);
+					ksys_ftruncate(wfd, body_len);
 				vcollected = kstrdup(collected, GFP_KERNEL);
 				state = CopyFile;
 			}
-- 
cgit v1.2.3


From 2ca2a09d6215fd9621aa3e2db7cc9428a61f2911 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski
Date: Sun, 11 Mar 2018 11:34:55 +0100
Subject: fs: add ksys_close() wrapper; remove in-kernel calls to sys_close()

Using the ksys_close() wrapper allows us to get rid of in-kernel calls
to the sys_close() syscall. The ksys_ prefix denotes that this function
is meant as a drop-in replacement for the syscall. In particular, it
uses the same calling convention as sys_close(), with one subtle
difference:

The few places which checked the return value did not care about the return
value re-writing in sys_close(), so simply use a wrapper around
__close_fd().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/autofs4/dev-ioctl.c   |  2 +-
 fs/binfmt_misc.c         |  2 +-
 fs/file.c                |  1 +
 fs/open.c                |  1 -
 include/linux/syscalls.h | 12 ++++++++++++
 init/do_mounts.c         |  4 ++--
 init/do_mounts_initrd.c  |  2 +-
 init/do_mounts_md.c      |  8 ++++----
 init/do_mounts_rd.c      |  6 +++---
 init/initramfs.c         |  8 ++++----
 10 files changed, 29 insertions(+), 17 deletions(-)

(limited to 'init')

diff --git a/fs/autofs4/dev-ioctl.c b/fs/autofs4/dev-ioctl.c
index b7c816f39404..26f6b4f41ce6 100644
--- a/fs/autofs4/dev-ioctl.c
+++ b/fs/autofs4/dev-ioctl.c
@@ -310,7 +310,7 @@ static int autofs_dev_ioctl_closemount(struct file *fp,
 				       struct autofs_sb_info *sbi,
 				       struct autofs_dev_ioctl *param)
 {
-	return sys_close(param->ioctlfd);
+	return ksys_close(param->ioctlfd);
 }
 
 /*
diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
index a7c5a9861bef..a41b48f82a70 100644
--- a/fs/binfmt_misc.c
+++ b/fs/binfmt_misc.c
@@ -241,7 +241,7 @@ ret:
 	return retval;
 error:
 	if (fd_binary > 0)
-		sys_close(fd_binary);
+		ksys_close(fd_binary);
 	bprm->interp_flags = 0;
 	bprm->interp_data = 0;
 	goto ret;
diff --git a/fs/file.c b/fs/file.c
index d304004f0b65..7ffd6e9d103d 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -638,6 +638,7 @@ out_unlock:
 	spin_unlock(&files->file_lock);
 	return -EBADF;
 }
+EXPORT_SYMBOL(__close_fd); /* for ksys_close() */
 
 void do_close_on_exec(struct files_struct *files)
 {
diff --git a/fs/open.c b/fs/open.c
index b3f3b2cd9f19..710102fc262b 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -1200,7 +1200,6 @@ SYSCALL_DEFINE1(close, unsigned int, fd)
 
 	return retval;
 }
-EXPORT_SYMBOL(sys_close);
 
 /*
  * This routine simulates a hangup on the tty, to arrange that users
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 41023177c8ec..38805f3447ea 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1045,4 +1045,16 @@ static inline long ksys_ftruncate(unsigned int fd, unsigned long length)
 	return do_sys_ftruncate(fd, length, 1);
 }
 
+extern int __close_fd(struct files_struct *files, unsigned int fd);
+
+/*
+ * In contrast to sys_close(), this stub does not check whether the syscall
+ * should or should not be restarted, but returns the raw error codes from
+ * __close_fd().
+ */
+static inline int ksys_close(unsigned int fd)
+{
+	return __close_fd(current->files, fd);
+}
+
 #endif
diff --git a/init/do_mounts.c b/init/do_mounts.c
index 89f18985fa90..a28dd42d1f84 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -492,7 +492,7 @@ void __init change_floppy(char *fmt, ...)
 	fd = sys_open("/dev/root", O_RDWR | O_NDELAY, 0);
 	if (fd >= 0) {
 		sys_ioctl(fd, FDEJECT, 0);
-		sys_close(fd);
+		ksys_close(fd);
 	}
 	printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
 	fd = sys_open("/dev/console", O_RDWR, 0);
@@ -503,7 +503,7 @@ void __init change_floppy(char *fmt, ...)
 		sys_read(fd, &c, 1);
 		termios.c_lflag |= ICANON;
 		sys_ioctl(fd, TCSETSF, (long)&termios);
-		sys_close(fd);
+		ksys_close(fd);
 	}
 }
 #endif
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index 99922d1ebfe6..6907c6dbc443 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -111,7 +111,7 @@ static void __init handle_initrd(void)
 			error = fd;
 		} else {
 			error = sys_ioctl(fd, BLKFLSBUF, 0);
-			sys_close(fd);
+			ksys_close(fd);
 		}
 		printk(!error ? "okay\n" : "failed\n");
 	}
diff --git a/init/do_mounts_md.c b/init/do_mounts_md.c
index 3f733c760a8c..ebd4013d589e 100644
--- a/init/do_mounts_md.c
+++ b/init/do_mounts_md.c
@@ -191,7 +191,7 @@ static void __init md_setup_drive(void)
 			printk(KERN_WARNING
 			       "md: Ignoring md=%d, already autodetected. (Use raid=noautodetect)\n",
 			       minor);
-			sys_close(fd);
+			ksys_close(fd);
 			continue;
 		}
 
@@ -243,11 +243,11 @@ static void __init md_setup_drive(void)
 			 * boot a kernel with devfs compiled in from partitioned md
 			 * array without it
 			 */
-			sys_close(fd);
+			ksys_close(fd);
 			fd = sys_open(name, 0, 0);
 			sys_ioctl(fd, BLKRRPART, 0);
 		}
-		sys_close(fd);
+		ksys_close(fd);
 	}
 }
 
@@ -297,7 +297,7 @@ static void __init autodetect_raid(void)
 	fd = sys_open("/dev/md0", 0, 0);
 	if (fd >= 0) {
 		sys_ioctl(fd, RAID_AUTORUN, raid_autopart);
-		sys_close(fd);
+		ksys_close(fd);
 	}
 }
 
diff --git a/init/do_mounts_rd.c b/init/do_mounts_rd.c
index 5b69056f610a..f1aa341862d3 100644
--- a/init/do_mounts_rd.c
+++ b/init/do_mounts_rd.c
@@ -257,7 +257,7 @@ int __init rd_load_image(char *from)
 		if (i && (i % devblocks == 0)) {
 			printk("done disk #%d.\n", disk++);
 			rotate = 0;
-			if (sys_close(in_fd)) {
+			if (ksys_close(in_fd)) {
 				printk("Error closing the disk.\n");
 				goto noclose_input;
 			}
@@ -283,9 +283,9 @@ int __init rd_load_image(char *from)
 successful_load:
 	res = 1;
 done:
-	sys_close(in_fd);
+	ksys_close(in_fd);
 noclose_input:
-	sys_close(out_fd);
+	ksys_close(out_fd);
 out:
 	kfree(buf);
 	ksys_unlink("/dev/ram");
diff --git a/init/initramfs.c b/init/initramfs.c
index 0d3b001b0dc5..ce2bcad97cdf 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -373,7 +373,7 @@ static int __init do_copy(void)
 	if (byte_count >= body_len) {
 		if (xwrite(wfd, victim, body_len) != body_len)
 			error("write error");
-		sys_close(wfd);
+		ksys_close(wfd);
 		do_utime(vcollected, mtime);
 		kfree(vcollected);
 		eat(body_len);
@@ -574,7 +574,7 @@ static void __init clean_rootfs(void)
 	buf = kzalloc(BUF_SIZE, GFP_KERNEL);
 	WARN_ON(!buf);
 	if (!buf) {
-		sys_close(fd);
+		ksys_close(fd);
 		return;
 	}
 
@@ -602,7 +602,7 @@ static void __init clean_rootfs(void)
 		num = sys_getdents64(fd, dirp, BUF_SIZE);
 	}
 
-	sys_close(fd);
+	ksys_close(fd);
 	kfree(buf);
 }
 #endif
@@ -639,7 +639,7 @@ static int __init populate_rootfs(void)
 				pr_err("/initrd.image: incomplete write (%zd != %ld)\n",
 				       written, initrd_end - initrd_start);
 
-			sys_close(fd);
+			ksys_close(fd);
 			free_initrd();
 		}
 	done:
-- 
cgit v1.2.3


From bae217ea8c7e123ed3fb1064909a262924771bbb Mon Sep 17 00:00:00 2001
From: Dominik Brodowski
Date: Sun, 11 Mar 2018 11:34:56 +0100
Subject: fs: add ksys_open() wrapper; remove in-kernel calls to sys_open()

Using this wrapper allows us to avoid the in-kernel calls to the
sys_open() syscall. The ksys_ prefix denotes that this function is meant
as a drop-in replacement for the syscall. In particular, it uses the
same calling convention as sys_open().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/open.c                |  2 +-
 include/linux/syscalls.h | 11 +++++++++++
 init/do_mounts.c         |  4 ++--
 init/do_mounts_initrd.c  |  4 ++--
 init/do_mounts_md.c      |  6 +++---
 init/do_mounts_rd.c      |  6 +++---
 init/initramfs.c         |  6 +++---
 init/main.c              |  2 +-
 8 files changed, 26 insertions(+), 15 deletions(-)

(limited to 'init')

diff --git a/fs/open.c b/fs/open.c
index 710102fc262b..8a42a2961130 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -1151,7 +1151,7 @@ COMPAT_SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, fla
  */
 SYSCALL_DEFINE2(creat, const char __user *, pathname, umode_t, mode)
 {
-	return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode);
+	return ksys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode);
 }
 
 #endif
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 38805f3447ea..f9df17dcec1c 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1057,4 +1057,15 @@ static inline int ksys_close(unsigned int fd)
 	return __close_fd(current->files, fd);
 }
 
+extern long do_sys_open(int dfd, const char __user *filename, int flags,
+			umode_t mode);
+
+static inline long ksys_open(const char __user *filename, int flags,
+			     umode_t mode)
+{
+	if (force_o_largefile())
+		flags |= O_LARGEFILE;
+	return do_sys_open(AT_FDCWD, filename, flags, mode);
+}
+
 #endif
diff --git a/init/do_mounts.c b/init/do_mounts.c
index a28dd42d1f84..cc1103477071 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -489,13 +489,13 @@ void __init change_floppy(char *fmt, ...)
 	va_start(args, fmt);
 	vsprintf(buf, fmt, args);
 	va_end(args);
-	fd = sys_open("/dev/root", O_RDWR | O_NDELAY, 0);
+	fd = ksys_open("/dev/root", O_RDWR | O_NDELAY, 0);
 	if (fd >= 0) {
 		sys_ioctl(fd, FDEJECT, 0);
 		ksys_close(fd);
 	}
 	printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
-	fd = sys_open("/dev/console", O_RDWR, 0);
+	fd = ksys_open("/dev/console", O_RDWR, 0);
 	if (fd >= 0) {
 		sys_ioctl(fd, TCGETS, (long)&termios);
 		termios.c_lflag &= ~ICANON;
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index 6907c6dbc443..cedca8fd2590 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -38,7 +38,7 @@ static int init_linuxrc(struct subprocess_info *info, struct cred *new)
 {
 	sys_unshare(CLONE_FS | CLONE_FILES);
 	/* stdin/stdout/stderr for /linuxrc */
-	sys_open("/dev/console", O_RDWR, 0);
+	ksys_open("/dev/console", O_RDWR, 0);
 	ksys_dup(0);
 	ksys_dup(0);
 	/* move initrd over / and chdir/chroot in initrd root */
@@ -99,7 +99,7 @@ static void __init handle_initrd(void)
 	if (!error)
 		printk("okay\n");
 	else {
-		int fd = sys_open("/dev/root.old", O_RDWR, 0);
+		int fd = ksys_open("/dev/root.old", O_RDWR, 0);
 		if (error == -ENOENT)
 			printk("/initrd does not exist. Ignored.\n");
 		else
diff --git a/init/do_mounts_md.c b/init/do_mounts_md.c
index ebd4013d589e..76dcfaada3ed 100644
--- a/init/do_mounts_md.c
+++ b/init/do_mounts_md.c
@@ -181,7 +181,7 @@ static void __init md_setup_drive(void)
 			partitioned ? "_d" : "", minor,
 			md_setup_args[ent].device_names);
 
-		fd = sys_open(name, 0, 0);
+		fd = ksys_open(name, 0, 0);
 		if (fd < 0) {
 			printk(KERN_ERR "md: open failed - cannot start "
 					"array %s\n", name);
@@ -244,7 +244,7 @@ static void __init md_setup_drive(void)
 			 * array without it
 			 */
 			ksys_close(fd);
-			fd = sys_open(name, 0, 0);
+			fd = ksys_open(name, 0, 0);
 			sys_ioctl(fd, BLKRRPART, 0);
 		}
 		ksys_close(fd);
@@ -294,7 +294,7 @@ static void __init autodetect_raid(void)
 
 	wait_for_device_probe();
 
-	fd = sys_open("/dev/md0", 0, 0);
+	fd = ksys_open("/dev/md0", 0, 0);
 	if (fd >= 0) {
 		sys_ioctl(fd, RAID_AUTORUN, raid_autopart);
 		ksys_close(fd);
diff --git a/init/do_mounts_rd.c b/init/do_mounts_rd.c
index f1aa341862d3..a6706314baa7 100644
--- a/init/do_mounts_rd.c
+++ b/init/do_mounts_rd.c
@@ -196,11 +196,11 @@ int __init rd_load_image(char *from)
 	char rotator[4] = { '|' , '/' , '-' , '\\' };
 #endif
 
-	out_fd = sys_open("/dev/ram", O_RDWR, 0);
+	out_fd = ksys_open("/dev/ram", O_RDWR, 0);
 	if (out_fd < 0)
 		goto out;
 
-	in_fd = sys_open(from, O_RDONLY, 0);
+	in_fd = ksys_open(from, O_RDONLY, 0);
 	if (in_fd < 0)
 		goto noclose_input;
 
@@ -262,7 +262,7 @@ int __init rd_load_image(char *from)
 				goto noclose_input;
 			}
 			change_floppy("disk #%d", disk);
-			in_fd = sys_open(from, O_RDONLY, 0);
+			in_fd = ksys_open(from, O_RDONLY, 0);
 			if (in_fd < 0)  {
 				printk("Error opening disk.\n");
 				goto noclose_input;
diff --git a/init/initramfs.c b/init/initramfs.c
index ce2bcad97cdf..5f2ff1d2370e 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -340,7 +340,7 @@ static int __init do_name(void)
 			int openflags = O_WRONLY|O_CREAT;
 			if (ml != 1)
 				openflags |= O_TRUNC;
-			wfd = sys_open(collected, openflags, mode);
+			wfd = ksys_open(collected, openflags, mode);
 
 			if (wfd >= 0) {
 				ksys_fchown(wfd, uid, gid);
@@ -567,7 +567,7 @@ static void __init clean_rootfs(void)
 	struct linux_dirent64 *dirp;
 	int num;
 
-	fd = sys_open("/", O_RDONLY, 0);
+	fd = ksys_open("/", O_RDONLY, 0);
 	WARN_ON(fd < 0);
 	if (fd < 0)
 		return;
@@ -629,7 +629,7 @@ static int __init populate_rootfs(void)
 		}
 		printk(KERN_INFO "rootfs image is not initramfs (%s)"
 				"; looks like an initrd\n", err);
-		fd = sys_open("/initrd.image",
+		fd = ksys_open("/initrd.image",
 			      O_WRONLY|O_CREAT, 0700);
 		if (fd >= 0) {
 			ssize_t written = xwrite(fd, (char *)initrd_start,
diff --git a/init/main.c b/init/main.c
index d0ded4322c6b..e77951ae2c19 100644
--- a/init/main.c
+++ b/init/main.c
@@ -1074,7 +1074,7 @@ static noinline void __init kernel_init_freeable(void)
 	do_basic_setup();
 
 	/* Open the /dev/console on the rootfs, this should never fail */
-	if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
+	if (ksys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
 		pr_err("Warning: unable to open an initial console.\n");
 
 	(void) ksys_dup(0);
-- 
cgit v1.2.3


From 454dab3f965ec24fda8fbe135c8dad4c5b238a86 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski
Date: Tue, 13 Mar 2018 21:34:04 +0100
Subject: fs: add ksys_getdents64() helper; remove in-kernel calls to
 sys_getdents64()

Using this helper allows us to avoid the in-kernel calls to the
sys_getdents64() syscall. The ksys_ prefix denotes that this function
is meant as a drop-in replacement for the syscall. In particular, it
uses the same calling convention as sys_getdents64().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/readdir.c             | 11 +++++++++--
 include/linux/syscalls.h |  2 ++
 init/initramfs.c         |  4 ++--
 3 files changed, 13 insertions(+), 4 deletions(-)

(limited to 'init')

diff --git a/fs/readdir.c b/fs/readdir.c
index 1b83b0ad183b..d97f548e6323 100644
--- a/fs/readdir.c
+++ b/fs/readdir.c
@@ -292,8 +292,8 @@ efault:
 	return -EFAULT;
 }
 
-SYSCALL_DEFINE3(getdents64, unsigned int, fd,
-		struct linux_dirent64 __user *, dirent, unsigned int, count)
+int ksys_getdents64(unsigned int fd, struct linux_dirent64 __user *dirent,
+		    unsigned int count)
 {
 	struct fd f;
 	struct linux_dirent64 __user * lastdirent;
@@ -326,6 +326,13 @@ SYSCALL_DEFINE3(getdents64, unsigned int, fd,
 	return error;
 }
 
+
+SYSCALL_DEFINE3(getdents64, unsigned int, fd,
+		struct linux_dirent64 __user *, dirent, unsigned int, count)
+{
+	return ksys_getdents64(fd, dirent, count);
+}
+
 #ifdef CONFIG_COMPAT
 struct compat_old_linux_dirent {
 	compat_ulong_t	d_ino;
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index f9df17dcec1c..c056aff6d7ad 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -955,6 +955,8 @@ ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count);
 int ksys_chdir(const char __user *filename);
 int ksys_fchmod(unsigned int fd, umode_t mode);
 int ksys_fchown(unsigned int fd, uid_t user, gid_t group);
+int ksys_getdents64(unsigned int fd, struct linux_dirent64 __user *dirent,
+		    unsigned int count);
 
 /*
  * The following kernel syscall equivalents are just wrappers to fs-internal
diff --git a/init/initramfs.c b/init/initramfs.c
index 5f2ff1d2370e..13643c46ebab 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -579,7 +579,7 @@ static void __init clean_rootfs(void)
 	}
 
 	dirp = buf;
-	num = sys_getdents64(fd, dirp, BUF_SIZE);
+	num = ksys_getdents64(fd, dirp, BUF_SIZE);
 	while (num > 0) {
 		while (num > 0) {
 			struct kstat st;
@@ -599,7 +599,7 @@ static void __init clean_rootfs(void)
 		}
 		dirp = buf;
 		memset(buf, 0, BUF_SIZE);
-		num = sys_getdents64(fd, dirp, BUF_SIZE);
+		num = ksys_getdents64(fd, dirp, BUF_SIZE);
 	}
 
 	ksys_close(fd);
-- 
cgit v1.2.3


From cbb60b924b9f3e4d7c67a1c9dcf981718f926e4e Mon Sep 17 00:00:00 2001
From: Dominik Brodowski
Date: Tue, 13 Mar 2018 21:43:59 +0100
Subject: fs: add ksys_ioctl() helper; remove in-kernel calls to sys_ioctl()

Using this helper allows us to avoid the in-kernel calls to the
sys_ioctl() syscall. The ksys_ prefix denotes that this function
is meant as a drop-in replacement for the syscall. In particular, it
uses the same calling convention as sys_ioctl().

After careful review, at least some of these calls could be converted
to do_vfs_ioctl() in future.

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/ioctl.c               |  7 ++++++-
 include/linux/syscalls.h |  1 +
 init/do_mounts.c         |  8 ++++----
 init/do_mounts_initrd.c  |  2 +-
 init/do_mounts_md.c      | 15 ++++++++-------
 init/do_mounts_rd.c      |  4 ++--
 6 files changed, 22 insertions(+), 15 deletions(-)

(limited to 'init')

diff --git a/fs/ioctl.c b/fs/ioctl.c
index 5ace7efb0d04..4823431d1c9d 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -689,7 +689,7 @@ int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
 	return error;
 }
 
-SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
+int ksys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg)
 {
 	int error;
 	struct fd f = fdget(fd);
@@ -702,3 +702,8 @@ SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
 	fdput(f);
 	return error;
 }
+
+SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
+{
+	return ksys_ioctl(fd, cmd, arg);
+}
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index c056aff6d7ad..5a959efd8fb7 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -957,6 +957,7 @@ int ksys_fchmod(unsigned int fd, umode_t mode);
 int ksys_fchown(unsigned int fd, uid_t user, gid_t group);
 int ksys_getdents64(unsigned int fd, struct linux_dirent64 __user *dirent,
 		    unsigned int count);
+int ksys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg);
 
 /*
  * The following kernel syscall equivalents are just wrappers to fs-internal
diff --git a/init/do_mounts.c b/init/do_mounts.c
index cc1103477071..b17e0095eb4e 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -491,18 +491,18 @@ void __init change_floppy(char *fmt, ...)
 	va_end(args);
 	fd = ksys_open("/dev/root", O_RDWR | O_NDELAY, 0);
 	if (fd >= 0) {
-		sys_ioctl(fd, FDEJECT, 0);
+		ksys_ioctl(fd, FDEJECT, 0);
 		ksys_close(fd);
 	}
 	printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
 	fd = ksys_open("/dev/console", O_RDWR, 0);
 	if (fd >= 0) {
-		sys_ioctl(fd, TCGETS, (long)&termios);
+		ksys_ioctl(fd, TCGETS, (long)&termios);
 		termios.c_lflag &= ~ICANON;
-		sys_ioctl(fd, TCSETSF, (long)&termios);
+		ksys_ioctl(fd, TCSETSF, (long)&termios);
 		sys_read(fd, &c, 1);
 		termios.c_lflag |= ICANON;
-		sys_ioctl(fd, TCSETSF, (long)&termios);
+		ksys_ioctl(fd, TCSETSF, (long)&termios);
 		ksys_close(fd);
 	}
 }
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index cedca8fd2590..03ec0c1b7553 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -110,7 +110,7 @@ static void __init handle_initrd(void)
 		if (fd < 0) {
 			error = fd;
 		} else {
-			error = sys_ioctl(fd, BLKFLSBUF, 0);
+			error = ksys_ioctl(fd, BLKFLSBUF, 0);
 			ksys_close(fd);
 		}
 		printk(!error ? "okay\n" : "failed\n");
diff --git a/init/do_mounts_md.c b/init/do_mounts_md.c
index 76dcfaada3ed..7d85d172bc7e 100644
--- a/init/do_mounts_md.c
+++ b/init/do_mounts_md.c
@@ -187,7 +187,7 @@ static void __init md_setup_drive(void)
 					"array %s\n", name);
 			continue;
 		}
-		if (sys_ioctl(fd, SET_ARRAY_INFO, 0) == -EBUSY) {
+		if (ksys_ioctl(fd, SET_ARRAY_INFO, 0) == -EBUSY) {
 			printk(KERN_WARNING
 			       "md: Ignoring md=%d, already autodetected. (Use raid=noautodetect)\n",
 			       minor);
@@ -210,7 +210,7 @@ static void __init md_setup_drive(void)
 			ainfo.state = (1 << MD_SB_CLEAN);
 			ainfo.layout = 0;
 			ainfo.chunk_size = md_setup_args[ent].chunk;
-			err = sys_ioctl(fd, SET_ARRAY_INFO, (long)&ainfo);
+			err = ksys_ioctl(fd, SET_ARRAY_INFO, (long)&ainfo);
 			for (i = 0; !err && i <= MD_SB_DISKS; i++) {
 				dev = devices[i];
 				if (!dev)
@@ -220,7 +220,8 @@ static void __init md_setup_drive(void)
 				dinfo.state = (1<<MD_DISK_ACTIVE)|(1<<MD_DISK_SYNC);
 				dinfo.major = MAJOR(dev);
 				dinfo.minor = MINOR(dev);
-				err = sys_ioctl(fd, ADD_NEW_DISK, (long)&dinfo);
+				err = ksys_ioctl(fd, ADD_NEW_DISK,
+						 (long)&dinfo);
 			}
 		} else {
 			/* persistent */
@@ -230,11 +231,11 @@ static void __init md_setup_drive(void)
 					break;
 				dinfo.major = MAJOR(dev);
 				dinfo.minor = MINOR(dev);
-				sys_ioctl(fd, ADD_NEW_DISK, (long)&dinfo);
+				ksys_ioctl(fd, ADD_NEW_DISK, (long)&dinfo);
 			}
 		}
 		if (!err)
-			err = sys_ioctl(fd, RUN_ARRAY, 0);
+			err = ksys_ioctl(fd, RUN_ARRAY, 0);
 		if (err)
 			printk(KERN_WARNING "md: starting md%d failed\n", minor);
 		else {
@@ -245,7 +246,7 @@ static void __init md_setup_drive(void)
 			 */
 			ksys_close(fd);
 			fd = ksys_open(name, 0, 0);
-			sys_ioctl(fd, BLKRRPART, 0);
+			ksys_ioctl(fd, BLKRRPART, 0);
 		}
 		ksys_close(fd);
 	}
@@ -296,7 +297,7 @@ static void __init autodetect_raid(void)
 
 	fd = ksys_open("/dev/md0", 0, 0);
 	if (fd >= 0) {
-		sys_ioctl(fd, RAID_AUTORUN, raid_autopart);
+		ksys_ioctl(fd, RAID_AUTORUN, raid_autopart);
 		ksys_close(fd);
 	}
 }
diff --git a/init/do_mounts_rd.c b/init/do_mounts_rd.c
index a6706314baa7..4dafaed5736f 100644
--- a/init/do_mounts_rd.c
+++ b/init/do_mounts_rd.c
@@ -218,7 +218,7 @@ int __init rd_load_image(char *from)
 	 * NOTE NOTE: nblocks is not actually blocks but
 	 * the number of kibibytes of data to load into a ramdisk.
 	 */
-	if (sys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
+	if (ksys_ioctl(out_fd, BLKGETSIZE, (unsigned long)&rd_blocks) < 0)
 		rd_blocks = 0;
 	else
 		rd_blocks >>= 1;
@@ -232,7 +232,7 @@ int __init rd_load_image(char *from)
 	/*
 	 * OK, time to copy in the data
 	 */
-	if (sys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
+	if (ksys_ioctl(in_fd, BLKGETSIZE, (unsigned long)&devblocks) < 0)
 		devblocks = 0;
 	else
 		devblocks >>= 1;
-- 
cgit v1.2.3


From 76847e4344350970e1c2e27c28b5abb3c588c5b3 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski
Date: Tue, 13 Mar 2018 21:51:17 +0100
Subject: fs: add ksys_lseek() helper; remove in-kernel calls to sys_lseek()

Using this helper allows us to avoid the in-kernel calls to the
sys_lseek() syscall. The ksys_ prefix denotes that this function
is meant as a drop-in replacement for the syscall. In particular, it
uses the same calling convention as sys_lseek().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/read_write.c          | 9 +++++++--
 include/linux/syscalls.h | 1 +
 init/do_mounts_rd.c      | 8 ++++----
 3 files changed, 12 insertions(+), 6 deletions(-)

(limited to 'init')

diff --git a/fs/read_write.c b/fs/read_write.c
index 8e8f0b4f52e2..b38b008a078e 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -301,7 +301,7 @@ loff_t vfs_llseek(struct file *file, loff_t offset, int whence)
 }
 EXPORT_SYMBOL(vfs_llseek);
 
-SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, whence)
+off_t ksys_lseek(unsigned int fd, off_t offset, unsigned int whence)
 {
 	off_t retval;
 	struct fd f = fdget_pos(fd);
@@ -319,10 +319,15 @@ SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, whence)
 	return retval;
 }
 
+SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, whence)
+{
+	return ksys_lseek(fd, offset, whence);
+}
+
 #ifdef CONFIG_COMPAT
 COMPAT_SYSCALL_DEFINE3(lseek, unsigned int, fd, compat_off_t, offset, unsigned int, whence)
 {
-	return sys_lseek(fd, offset, whence);
+	return ksys_lseek(fd, offset, whence);
 }
 #endif
 
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 5a959efd8fb7..0f24e5334569 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -958,6 +958,7 @@ int ksys_fchown(unsigned int fd, uid_t user, gid_t group);
 int ksys_getdents64(unsigned int fd, struct linux_dirent64 __user *dirent,
 		    unsigned int count);
 int ksys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg);
+off_t ksys_lseek(unsigned int fd, off_t offset, unsigned int whence);
 
 /*
  * The following kernel syscall equivalents are just wrappers to fs-internal
diff --git a/init/do_mounts_rd.c b/init/do_mounts_rd.c
index 4dafaed5736f..13e54148c0e0 100644
--- a/init/do_mounts_rd.c
+++ b/init/do_mounts_rd.c
@@ -90,7 +90,7 @@ identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
 	/*
 	 * Read block 0 to test for compressed kernel
 	 */
-	sys_lseek(fd, start_block * BLOCK_SIZE, 0);
+	ksys_lseek(fd, start_block * BLOCK_SIZE, 0);
 	sys_read(fd, buf, size);
 
 	*decompressor = decompress_method(buf, size, &compress_name);
@@ -136,7 +136,7 @@ identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
 	/*
 	 * Read 512 bytes further to check if cramfs is padded
 	 */
-	sys_lseek(fd, start_block * BLOCK_SIZE + 0x200, 0);
+	ksys_lseek(fd, start_block * BLOCK_SIZE + 0x200, 0);
 	sys_read(fd, buf, size);
 
 	if (cramfsb->magic == CRAMFS_MAGIC) {
@@ -150,7 +150,7 @@ identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
 	/*
 	 * Read block 1 to test for minix and ext2 superblock
 	 */
-	sys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
+	ksys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
 	sys_read(fd, buf, size);
 
 	/* Try minix */
@@ -178,7 +178,7 @@ identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
 	       start_block);
 
 done:
-	sys_lseek(fd, start_block * BLOCK_SIZE, 0);
+	ksys_lseek(fd, start_block * BLOCK_SIZE, 0);
 	kfree(buf);
 	return nblocks;
 }
-- 
cgit v1.2.3


From 3ce4a7bf66263748194b77ccefd284be963c6304 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski
Date: Tue, 13 Mar 2018 21:56:26 +0100
Subject: fs: add ksys_read() helper; remove in-kernel calls to sys_read()

Using this helper allows us to avoid the in-kernel calls to the
sys_read() syscall. The ksys_ prefix denotes that this function
is meant as a drop-in replacement for the syscall. In particular, it
uses the same calling convention as sys_read().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 arch/s390/kernel/compat_linux.c |  2 +-
 fs/read_write.c                 |  7 ++++++-
 include/linux/syscalls.h        |  1 +
 init/do_mounts.c                |  2 +-
 init/do_mounts_rd.c             | 10 +++++-----
 5 files changed, 14 insertions(+), 8 deletions(-)

(limited to 'init')

diff --git a/arch/s390/kernel/compat_linux.c b/arch/s390/kernel/compat_linux.c
index 9c5e975f71a6..af0469f204fd 100644
--- a/arch/s390/kernel/compat_linux.c
+++ b/arch/s390/kernel/compat_linux.c
@@ -460,7 +460,7 @@ COMPAT_SYSCALL_DEFINE3(s390_read, unsigned int, fd, char __user *, buf, compat_s
 	if ((compat_ssize_t) count < 0)
 		return -EINVAL; 
 
-	return sys_read(fd, buf, count);
+	return ksys_read(fd, buf, count);
 }
 
 COMPAT_SYSCALL_DEFINE3(s390_write, unsigned int, fd, const char __user *, buf, compat_size_t, count)
diff --git a/fs/read_write.c b/fs/read_write.c
index b38b008a078e..fc441e1ac683 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -568,7 +568,7 @@ static inline void file_pos_write(struct file *file, loff_t pos)
 	file->f_pos = pos;
 }
 
-SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count)
+ssize_t ksys_read(unsigned int fd, char __user *buf, size_t count)
 {
 	struct fd f = fdget_pos(fd);
 	ssize_t ret = -EBADF;
@@ -583,6 +583,11 @@ SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count)
 	return ret;
 }
 
+SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count)
+{
+	return ksys_read(fd, buf, count);
+}
+
 ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count)
 {
 	struct fd f = fdget_pos(fd);
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 0f24e5334569..3a2e90842ff8 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -959,6 +959,7 @@ int ksys_getdents64(unsigned int fd, struct linux_dirent64 __user *dirent,
 		    unsigned int count);
 int ksys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg);
 off_t ksys_lseek(unsigned int fd, off_t offset, unsigned int whence);
+ssize_t ksys_read(unsigned int fd, char __user *buf, size_t count);
 
 /*
  * The following kernel syscall equivalents are just wrappers to fs-internal
diff --git a/init/do_mounts.c b/init/do_mounts.c
index b17e0095eb4e..2c71dabe5626 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -500,7 +500,7 @@ void __init change_floppy(char *fmt, ...)
 		ksys_ioctl(fd, TCGETS, (long)&termios);
 		termios.c_lflag &= ~ICANON;
 		ksys_ioctl(fd, TCSETSF, (long)&termios);
-		sys_read(fd, &c, 1);
+		ksys_read(fd, &c, 1);
 		termios.c_lflag |= ICANON;
 		ksys_ioctl(fd, TCSETSF, (long)&termios);
 		ksys_close(fd);
diff --git a/init/do_mounts_rd.c b/init/do_mounts_rd.c
index 13e54148c0e0..12c159824c7b 100644
--- a/init/do_mounts_rd.c
+++ b/init/do_mounts_rd.c
@@ -91,7 +91,7 @@ identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
 	 * Read block 0 to test for compressed kernel
 	 */
 	ksys_lseek(fd, start_block * BLOCK_SIZE, 0);
-	sys_read(fd, buf, size);
+	ksys_read(fd, buf, size);
 
 	*decompressor = decompress_method(buf, size, &compress_name);
 	if (compress_name) {
@@ -137,7 +137,7 @@ identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
 	 * Read 512 bytes further to check if cramfs is padded
 	 */
 	ksys_lseek(fd, start_block * BLOCK_SIZE + 0x200, 0);
-	sys_read(fd, buf, size);
+	ksys_read(fd, buf, size);
 
 	if (cramfsb->magic == CRAMFS_MAGIC) {
 		printk(KERN_NOTICE
@@ -151,7 +151,7 @@ identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
 	 * Read block 1 to test for minix and ext2 superblock
 	 */
 	ksys_lseek(fd, (start_block+1) * BLOCK_SIZE, 0);
-	sys_read(fd, buf, size);
+	ksys_read(fd, buf, size);
 
 	/* Try minix */
 	if (minixsb->s_magic == MINIX_SUPER_MAGIC ||
@@ -269,7 +269,7 @@ int __init rd_load_image(char *from)
 			}
 			printk("Loading disk #%d... ", disk);
 		}
-		sys_read(in_fd, buf, BLOCK_SIZE);
+		ksys_read(in_fd, buf, BLOCK_SIZE);
 		ksys_write(out_fd, buf, BLOCK_SIZE);
 #if !defined(CONFIG_S390)
 		if (!(i % 16)) {
@@ -307,7 +307,7 @@ static int crd_infd, crd_outfd;
 
 static long __init compr_fill(void *buf, unsigned long len)
 {
-	long r = sys_read(crd_infd, buf, len);
+	long r = ksys_read(crd_infd, buf, len);
 	if (r < 0)
 		printk(KERN_ERR "RAMDISK: error while reading compressed data");
 	else if (r == 0)
-- 
cgit v1.2.3


From 9b32105ec6b13d32d5db6a6e7992c97ce54b5ea7 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski
Date: Sun, 11 Mar 2018 11:34:42 +0100
Subject: kernel: add ksys_unshare() helper; remove in-kernel calls to
 sys_unshare()

Using this helper allows us to avoid the in-kernel calls to the
sys_unshare() syscall. The ksys_ prefix denotes that this function is meant
as a drop-in replacement for the syscall. In particular, it uses the same
calling convention as sys_unshare().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 drivers/base/devtmpfs.c  | 2 +-
 include/linux/syscalls.h | 1 +
 init/do_mounts_initrd.c  | 2 +-
 kernel/fork.c            | 7 ++++++-
 4 files changed, 9 insertions(+), 3 deletions(-)

(limited to 'init')

diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index 3f7ee954fd2c..f7768077e817 100644
--- a/drivers/base/devtmpfs.c
+++ b/drivers/base/devtmpfs.c
@@ -380,7 +380,7 @@ static int devtmpfsd(void *p)
 {
 	char options[] = "mode=0755";
 	int *err = p;
-	*err = sys_unshare(CLONE_NEWNS);
+	*err = ksys_unshare(CLONE_NEWNS);
 	if (*err)
 		goto out;
 	*err = ksys_mount("devtmpfs", "/", "devtmpfs", MS_SILENT, options);
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 0a9942b3e718..e724dda509e0 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -961,6 +961,7 @@ int ksys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg);
 off_t ksys_lseek(unsigned int fd, off_t offset, unsigned int whence);
 ssize_t ksys_read(unsigned int fd, char __user *buf, size_t count);
 void ksys_sync(void);
+int ksys_unshare(unsigned long unshare_flags);
 
 /*
  * The following kernel syscall equivalents are just wrappers to fs-internal
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index 03ec0c1b7553..d1d3e53bdeef 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -36,7 +36,7 @@ __setup("noinitrd", no_initrd);
 
 static int init_linuxrc(struct subprocess_info *info, struct cred *new)
 {
-	sys_unshare(CLONE_FS | CLONE_FILES);
+	ksys_unshare(CLONE_FS | CLONE_FILES);
 	/* stdin/stdout/stderr for /linuxrc */
 	ksys_open("/dev/console", O_RDWR, 0);
 	ksys_dup(0);
diff --git a/kernel/fork.c b/kernel/fork.c
index b1e031aac9db..f71b67dc156d 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2354,7 +2354,7 @@ static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp
  * constructed. Here we are modifying the current, active,
  * task_struct.
  */
-SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags)
+int ksys_unshare(unsigned long unshare_flags)
 {
 	struct fs_struct *fs, *new_fs = NULL;
 	struct files_struct *fd, *new_fd = NULL;
@@ -2470,6 +2470,11 @@ bad_unshare_out:
 	return err;
 }
 
+SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags)
+{
+	return ksys_unshare(unshare_flags);
+}
+
 /*
  *	Helper to unshare the files of the current task.
  *	We don't want to expose copy_files internals to
-- 
cgit v1.2.3


From e2aaa9f423367ee03755d632555c242629a08d00 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski
Date: Fri, 16 Mar 2018 12:36:06 +0100
Subject: kernel: add ksys_setsid() helper; remove in-kernel call to
 sys_setsid()

Using this helper allows us to avoid the in-kernel call to the
sys_setsid() syscall. The ksys_ prefix denotes that this function
is meant as a drop-in replacement for the syscall. In particular, it
uses the same calling convention as sys_setsid().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 include/linux/syscalls.h | 1 +
 init/do_mounts_initrd.c  | 2 +-
 kernel/sys.c             | 7 ++++++-
 3 files changed, 8 insertions(+), 2 deletions(-)

(limited to 'init')

diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index e724dda509e0..4dd685ee425d 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -962,6 +962,7 @@ off_t ksys_lseek(unsigned int fd, off_t offset, unsigned int whence);
 ssize_t ksys_read(unsigned int fd, char __user *buf, size_t count);
 void ksys_sync(void);
 int ksys_unshare(unsigned long unshare_flags);
+int ksys_setsid(void);
 
 /*
  * The following kernel syscall equivalents are just wrappers to fs-internal
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index d1d3e53bdeef..5a91aefa7305 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -45,7 +45,7 @@ static int init_linuxrc(struct subprocess_info *info, struct cred *new)
 	ksys_chdir("/root");
 	ksys_mount(".", "/", NULL, MS_MOVE, NULL);
 	ksys_chroot(".");
-	sys_setsid();
+	ksys_setsid();
 	return 0;
 }
 
diff --git a/kernel/sys.c b/kernel/sys.c
index 550f47788ae4..ad692183dfe9 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1150,7 +1150,7 @@ static void set_special_pids(struct pid *pid)
 		change_pid(curr, PIDTYPE_PGID, pid);
 }
 
-SYSCALL_DEFINE0(setsid)
+int ksys_setsid(void)
 {
 	struct task_struct *group_leader = current->group_leader;
 	struct pid *sid = task_pid(group_leader);
@@ -1183,6 +1183,11 @@ out:
 	return err;
 }
 
+SYSCALL_DEFINE0(setsid)
+{
+	return ksys_setsid();
+}
+
 DECLARE_RWSEM(uts_sem);
 
 #ifdef COMPAT_UTS_MACHINE
-- 
cgit v1.2.3