Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull siginfo cleanups from Eric Biederman:
 "Long ago when 2.4 was just a testing release copy_siginfo_to_user was
  made to copy individual fields to userspace, possibly for efficiency
  and to ensure initialized values were not copied to userspace.

  Unfortunately the design was complex, it's assumptions unstated, and
  humans are fallible and so while it worked much of the time that
  design failed to ensure unitialized memory is not copied to userspace.

  This set of changes is part of a new design to clean up siginfo and
  simplify things, and hopefully make the siginfo handling robust enough
  that a simple inspection of the code can be made to ensure we don't
  copy any unitializied fields to userspace.

  The design is to unify struct siginfo and struct compat_siginfo into a
  single definition that is shared between all architectures so that
  anyone adding to the set of information shared with struct siginfo can
  see the whole picture. Hopefully ensuring all future si_code
  assignments are arch independent.

  The design is to unify copy_siginfo_to_user32 and
  copy_siginfo_from_user32 so that those function are complete and cope
  with all of the different cases documented in signinfo_layout. I don't
  think there was a single implementation of either of those functions
  that was complete and correct before my changes unified them.

  The design is to introduce a series of helpers including
  force_siginfo_fault that take the values that are needed in struct
  siginfo and build the siginfo structure for their callers. Ensuring
  struct siginfo is built correctly.

  The remaining work for 4.17 (unless someone thinks it is post -rc1
  material) is to push usage of those helpers down into the
  architectures so that architecture specific code will not need to deal
  with the fiddly work of intializing struct siginfo, and then when
  struct siginfo is guaranteed to be fully initialized change copy
  siginfo_to_user into a simple wrapper around copy_to_user.

  Further there is work in progress on the issues that have been
  documented requires arch specific knowledge to sort out.

  The changes below fix or at least document all of the issues that have
  been found with siginfo generation. Then proceed to unify struct
  siginfo the 32 bit helpers that copy siginfo to and from userspace,
  and generally clean up anything that is not arch specific with regards
  to siginfo generation.

  It is a lot but with the unification you can of siginfo you can
  already see the code reduction in the kernel"

* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (45 commits)
  signal/memory-failure: Use force_sig_mceerr and send_sig_mceerr
  mm/memory_failure: Remove unused trapno from memory_failure
  signal/ptrace: Add force_sig_ptrace_errno_trap and use it where needed
  signal/powerpc: Remove unnecessary signal_code parameter of do_send_trap
  signal: Helpers for faults with specialized siginfo layouts
  signal: Add send_sig_fault and force_sig_fault
  signal: Replace memset(info,...) with clear_siginfo for clarity
  signal: Don't use structure initializers for struct siginfo
  signal/arm64: Better isolate the COMPAT_TASK portion of ptrace_hbptriggered
  ptrace: Use copy_siginfo in setsiginfo and getsiginfo
  signal: Unify and correct copy_siginfo_to_user32
  signal: Remove the code to clear siginfo before calling copy_siginfo_from_user32
  signal: Unify and correct copy_siginfo_from_user32
  signal/blackfin: Remove pointless UID16_SIGINFO_COMPAT_NEEDED
  signal/blackfin: Move the blackfin specific si_codes to asm-generic/siginfo.h
  signal/tile: Move the tile specific si_codes to asm-generic/siginfo.h
  signal/frv: Move the frv specific si_codes to asm-generic/siginfo.h
  signal/ia64: Move the ia64 specific si_codes to asm-generic/siginfo.h
  signal/powerpc: Remove redefinition of NSIGTRAP on powerpc
  signal: Move addr_lsb into the _sigfault union for clarity
  ...

3 files changed, 21 insertions, 31 deletions

diff --git a/mm/hwpoison-inject.c b/mm/hwpoison-inject.c
index 356df057a2a8..b6ac70616c32 100644
--- a/mm/hwpoison-inject.c
+++ b/mm/hwpoison-inject.c
@@ -52,7 +52,7 @@ static int hwpoison_inject(void *data, u64 val)
 
 inject:
 	pr_info("Injecting memory failure at pfn %#lx\n", pfn);
-	return memory_failure(pfn, 18, MF_COUNT_INCREASED);
+	return memory_failure(pfn, MF_COUNT_INCREASED);
 put_out:
 	put_hwpoison_page(p);
 	return 0;
diff --git a/mm/madvise.c b/mm/madvise.c
index 751e97aa2210..4d3c922ea1a1 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -661,7 +661,7 @@ static int madvise_inject_error(int behavior,
 		pr_info("Injecting memory failure for pfn %#lx at process virtual address %#lx\n",
 						page_to_pfn(page), start);
 
-		ret = memory_failure(page_to_pfn(page), 0, MF_COUNT_INCREASED);
+		ret = memory_failure(page_to_pfn(page), MF_COUNT_INCREASED);
 		if (ret)
 			return ret;
 	}
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 4acdf393a801..4b80ccee4535 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -178,25 +178,19 @@ EXPORT_SYMBOL_GPL(hwpoison_filter);
  * ``action optional'' if they are not immediately affected by the error
  * ``action required'' if error happened in current execution context
  */
-static int kill_proc(struct task_struct *t, unsigned long addr, int trapno,
+static int kill_proc(struct task_struct *t, unsigned long addr,
 			unsigned long pfn, struct page *page, int flags)
 {
-	struct siginfo si;
+	short addr_lsb;
 	int ret;
 
 	pr_err("Memory failure: %#lx: Killing %s:%d due to hardware memory corruption\n",
 		pfn, t->comm, t->pid);
-	si.si_signo = SIGBUS;
-	si.si_errno = 0;
-	si.si_addr = (void *)addr;
-#ifdef __ARCH_SI_TRAPNO
-	si.si_trapno = trapno;
-#endif
-	si.si_addr_lsb = compound_order(compound_head(page)) + PAGE_SHIFT;
+	addr_lsb = compound_order(compound_head(page)) + PAGE_SHIFT;
 
 	if ((flags & MF_ACTION_REQUIRED) && t->mm == current->mm) {
-		si.si_code = BUS_MCEERR_AR;
-		ret = force_sig_info(SIGBUS, &si, current);
+		ret = force_sig_mceerr(BUS_MCEERR_AR, (void __user *)addr,
+				       addr_lsb, current);
 	} else {
 		/*
 		 * Don't use force here, it's convenient if the signal
@@ -204,8 +198,8 @@ static int kill_proc(struct task_struct *t, unsigned long addr, int trapno,
 		 * This could cause a loop when the user sets SIGBUS
 		 * to SIG_IGN, but hopefully no one will do that?
 		 */
-		si.si_code = BUS_MCEERR_AO;
-		ret = send_sig_info(SIGBUS, &si, t);  /* synchronous? */
+		ret = send_sig_mceerr(BUS_MCEERR_AO, (void __user *)addr,
+				      addr_lsb, t);  /* synchronous? */
 	}
 	if (ret < 0)
 		pr_info("Memory failure: Error sending signal to %s:%d: %d\n",
@@ -323,7 +317,7 @@ static void add_to_kill(struct task_struct *tsk, struct page *p,
  * Also when FAIL is set do a force kill because something went
  * wrong earlier.
  */
-static void kill_procs(struct list_head *to_kill, int forcekill, int trapno,
+static void kill_procs(struct list_head *to_kill, int forcekill,
 			  bool fail, struct page *page, unsigned long pfn,
 			  int flags)
 {
@@ -348,7 +342,7 @@ static void kill_procs(struct list_head *to_kill, int forcekill, int trapno,
 			 * check for that, but we need to tell the
 			 * process anyways.
 			 */
-			else if (kill_proc(tk->tsk, tk->addr, trapno,
+			else if (kill_proc(tk->tsk, tk->addr,
 					      pfn, page, flags) < 0)
 				pr_err("Memory failure: %#lx: Cannot send advisory machine check signal to %s:%d\n",
 				       pfn, tk->tsk->comm, tk->tsk->pid);
@@ -927,7 +921,7 @@ EXPORT_SYMBOL_GPL(get_hwpoison_page);
  * the pages and send SIGBUS to the processes if the data was dirty.
  */
 static bool hwpoison_user_mappings(struct page *p, unsigned long pfn,
-				  int trapno, int flags, struct page **hpagep)
+				  int flags, struct page **hpagep)
 {
 	enum ttu_flags ttu = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS;
 	struct address_space *mapping;
@@ -1017,7 +1011,7 @@ static bool hwpoison_user_mappings(struct page *p, unsigned long pfn,
 	 * any accesses to the poisoned memory.
 	 */
 	forcekill = PageDirty(hpage) || (flags & MF_MUST_KILL);
-	kill_procs(&tokill, forcekill, trapno, !unmap_success, p, pfn, flags);
+	kill_procs(&tokill, forcekill, !unmap_success, p, pfn, flags);
 
 	return unmap_success;
 }
@@ -1045,7 +1039,7 @@ static int identify_page_state(unsigned long pfn, struct page *p,
 	return page_action(ps, p, pfn);
 }
 
-static int memory_failure_hugetlb(unsigned long pfn, int trapno, int flags)
+static int memory_failure_hugetlb(unsigned long pfn, int flags)
 {
 	struct page *p = pfn_to_page(pfn);
 	struct page *head = compound_head(p);
@@ -1090,7 +1084,7 @@ static int memory_failure_hugetlb(unsigned long pfn, int trapno, int flags)
 		return 0;
 	}
 
-	if (!hwpoison_user_mappings(p, pfn, trapno, flags, &head)) {
+	if (!hwpoison_user_mappings(p, pfn, flags, &head)) {
 		action_result(pfn, MF_MSG_UNMAP_FAILED, MF_IGNORED);
 		res = -EBUSY;
 		goto out;
@@ -1105,7 +1099,6 @@ out:
 /**
  * memory_failure - Handle memory failure of a page.
  * @pfn: Page Number of the corrupted page
- * @trapno: Trap number reported in the signal to user space.
  * @flags: fine tune action taken
  *
  * This function is called by the low level machine check code
@@ -1120,7 +1113,7 @@ out:
  * Must run in process context (e.g. a work queue) with interrupts
  * enabled and no spinlocks hold.
  */
-int memory_failure(unsigned long pfn, int trapno, int flags)
+int memory_failure(unsigned long pfn, int flags)
 {
 	struct page *p;
 	struct page *hpage;
@@ -1129,7 +1122,7 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
 	unsigned long page_flags;
 
 	if (!sysctl_memory_failure_recovery)
-		panic("Memory failure from trap %d on page %lx", trapno, pfn);
+		panic("Memory failure on page %lx", pfn);
 
 	if (!pfn_valid(pfn)) {
 		pr_err("Memory failure: %#lx: memory outside kernel control\n",
@@ -1139,7 +1132,7 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
 
 	p = pfn_to_page(pfn);
 	if (PageHuge(p))
-		return memory_failure_hugetlb(pfn, trapno, flags);
+		return memory_failure_hugetlb(pfn, flags);
 	if (TestSetPageHWPoison(p)) {
 		pr_err("Memory failure: %#lx: already hardware poisoned\n",
 			pfn);
@@ -1268,7 +1261,7 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
 	 * When the raw error page is thp tail page, hpage points to the raw
 	 * page after thp split.
 	 */
-	if (!hwpoison_user_mappings(p, pfn, trapno, flags, &hpage)) {
+	if (!hwpoison_user_mappings(p, pfn, flags, &hpage)) {
 		action_result(pfn, MF_MSG_UNMAP_FAILED, MF_IGNORED);
 		res = -EBUSY;
 		goto out;
@@ -1296,7 +1289,6 @@ EXPORT_SYMBOL_GPL(memory_failure);
 
 struct memory_failure_entry {
 	unsigned long pfn;
-	int trapno;
 	int flags;
 };
 
@@ -1312,7 +1304,6 @@ static DEFINE_PER_CPU(struct memory_failure_cpu, memory_failure_cpu);
 /**
  * memory_failure_queue - Schedule handling memory failure of a page.
  * @pfn: Page Number of the corrupted page
- * @trapno: Trap number reported in the signal to user space.
  * @flags: Flags for memory failure handling
  *
  * This function is called by the low level hardware error handler
@@ -1326,13 +1317,12 @@ static DEFINE_PER_CPU(struct memory_failure_cpu, memory_failure_cpu);
  *
  * Can run in IRQ context.
  */
-void memory_failure_queue(unsigned long pfn, int trapno, int flags)
+void memory_failure_queue(unsigned long pfn, int flags)
 {
 	struct memory_failure_cpu *mf_cpu;
 	unsigned long proc_flags;
 	struct memory_failure_entry entry = {
 		.pfn =		pfn,
-		.trapno =	trapno,
 		.flags =	flags,
 	};
 
@@ -1365,7 +1355,7 @@ static void memory_failure_work_func(struct work_struct *work)
 		if (entry.flags & MF_SOFT_OFFLINE)
 			soft_offline_page(pfn_to_page(entry.pfn), entry.flags);
 		else
-			memory_failure(entry.pfn, entry.trapno, entry.flags);
+			memory_failure(entry.pfn, entry.flags);
 	}
 }