sh: remove CONFIG_SET_FS support

sh uses set_fs/get_fs only in one file, to handle address
errors in both user and kernel memory.

It already has an abstraction to differentiate between I/O
and memory, so adding a third class for kernel memory fits
into the same scheme and lets us kill off CONFIG_SET_FS.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

3 files changed, 21 insertions, 20 deletions

diff --git a/arch/sh/kernel/io_trapped.c b/arch/sh/kernel/io_trapped.c
index 004ad0130b10..e803b14ef12e 100644
--- a/arch/sh/kernel/io_trapped.c
+++ b/arch/sh/kernel/io_trapped.c
@@ -270,7 +270,6 @@ static struct mem_access trapped_io_access = {
 
 int handle_trapped_io(struct pt_regs *regs, unsigned long address)
 {
-	mm_segment_t oldfs;
 	insn_size_t instruction;
 	int tmp;
 
@@ -281,16 +280,12 @@ int handle_trapped_io(struct pt_regs *regs, unsigned long address)
 
 	WARN_ON(user_mode(regs));
 
-	oldfs = get_fs();
-	set_fs(KERNEL_DS);
-	if (copy_from_user(&instruction, (void *)(regs->pc),
-			   sizeof(instruction))) {
-		set_fs(oldfs);
+	if (copy_from_kernel_nofault(&instruction, (void *)(regs->pc),
+				     sizeof(instruction))) {
 		return 0;
 	}
 
 	tmp = handle_unaligned_access(instruction, regs,
 				      &trapped_io_access, 1, address);
-	set_fs(oldfs);
 	return tmp == 0;
 }
diff --git a/arch/sh/kernel/process_32.c b/arch/sh/kernel/process_32.c
index 1c28e3cddb60..ca01286a0610 100644
--- a/arch/sh/kernel/process_32.c
+++ b/arch/sh/kernel/process_32.c
@@ -123,7 +123,6 @@ int copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long arg,
 #if defined(CONFIG_SH_FPU)
 		childregs->sr |= SR_FD;
 #endif
-		ti->addr_limit = KERNEL_DS;
 		ti->status &= ~TS_USEDFPU;
 		p->thread.fpu_counter = 0;
 		return 0;
@@ -132,7 +131,6 @@ int copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long arg,
 
 	if (usp)
 		childregs->regs[15] = usp;
-	ti->addr_limit = USER_DS;
 
 	if (clone_flags & CLONE_SETTLS)
 		childregs->gbr = tls;
diff --git a/arch/sh/kernel/traps_32.c b/arch/sh/kernel/traps_32.c
index b3c715bc254b..6cdda3a621a1 100644
--- a/arch/sh/kernel/traps_32.c
+++ b/arch/sh/kernel/traps_32.c
@@ -75,6 +75,23 @@ static struct mem_access user_mem_access = {
 	copy_to_user,
 };
 
+static unsigned long copy_from_kernel_wrapper(void *dst, const void __user *src,
+					      unsigned long cnt)
+{
+	return copy_from_kernel_nofault(dst, (const void __force *)src, cnt);
+}
+
+static unsigned long copy_to_kernel_wrapper(void __user *dst, const void *src,
+					    unsigned long cnt)
+{
+	return copy_to_kernel_nofault((void __force *)dst, src, cnt);
+}
+
+static struct mem_access kernel_mem_access = {
+	copy_from_kernel_wrapper,
+	copy_to_kernel_wrapper,
+};
+
 /*
  * handle an instruction that does an unaligned memory access by emulating the
  * desired behaviour
@@ -473,7 +490,6 @@ asmlinkage void do_address_error(struct pt_regs *regs,
 				 unsigned long address)
 {
 	unsigned long error_code = 0;
-	mm_segment_t oldfs;
 	insn_size_t instruction;
 	int tmp;
 
@@ -489,13 +505,10 @@ asmlinkage void do_address_error(struct pt_regs *regs,
 		local_irq_enable();
 		inc_unaligned_user_access();
 
-		oldfs = force_uaccess_begin();
 		if (copy_from_user(&instruction, (insn_size_t __user *)(regs->pc & ~1),
 				   sizeof(instruction))) {
-			force_uaccess_end(oldfs);
 			goto uspace_segv;
 		}
-		force_uaccess_end(oldfs);
 
 		/* shout about userspace fixups */
 		unaligned_fixups_notify(current, instruction, regs);
@@ -518,11 +531,9 @@ fixup:
 			goto uspace_segv;
 		}
 
-		oldfs = force_uaccess_begin();
 		tmp = handle_unaligned_access(instruction, regs,
 					      &user_mem_access, 0,
 					      address);
-		force_uaccess_end(oldfs);
 
 		if (tmp == 0)
 			return; /* sorted */
@@ -538,21 +549,18 @@ uspace_segv:
 		if (regs->pc & 1)
 			die("unaligned program counter", regs, error_code);
 
-		set_fs(KERNEL_DS);
-		if (copy_from_user(&instruction, (void __user *)(regs->pc),
+		if (copy_from_kernel_nofault(&instruction, (void *)(regs->pc),
 				   sizeof(instruction))) {
 			/* Argh. Fault on the instruction itself.
 			   This should never happen non-SMP
 			*/
-			set_fs(oldfs);
 			die("insn faulting in do_address_error", regs, 0);
 		}
 
 		unaligned_fixups_notify(current, instruction, regs);
 
-		handle_unaligned_access(instruction, regs, &user_mem_access,
+		handle_unaligned_access(instruction, regs, &kernel_mem_access,
 					0, address);
-		set_fs(oldfs);
 	}
 }