Merge branch 'for-v5.13-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull siginfo fix from Eric Biederman:
 "During the merge window an issue with si_perf and the siginfo ABI came
  up. The alpha and sparc siginfo structure layout had changed with the
  addition of SIGTRAP TRAP_PERF and the new field si_perf.

  The reason only alpha and sparc were affected is that they are the
  only architectures that use si_trapno.

  Looking deeper it was discovered that si_trapno is used for only a few
  select signals on alpha and sparc, and that none of the other
  _sigfault fields past si_addr are used at all. Which means technically
  no regression on alpha and sparc.

  While the alignment concerns might be dismissed the abuse of si_errno
  by SIGTRAP TRAP_PERF does have the potential to cause regressions in
  existing userspace.

  While we still have time before userspace starts using and depending
  on the new definition siginfo for SIGTRAP TRAP_PERF this set of
  changes cleans up siginfo_t.

   - The si_trapno field is demoted from magic alpha and sparc status
     and made an ordinary union member of the _sigfault member of
     siginfo_t. Without moving it of course.

   - si_perf is replaced with si_perf_data and si_perf_type ending the
     abuse of si_errno.

   - Unnecessary additions to signalfd_siginfo are removed"

* 'for-v5.13-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  signalfd: Remove SIL_PERF_EVENT fields from signalfd_siginfo
  signal: Deliver all of the siginfo perf data in _perf
  signal: Factor force_sig_perf out of perf_sigtrap
  signal: Implement SIL_FAULT_TRAPNO
  siginfo: Move si_trapno inside the union inside _si_fault

2 files changed, 36 insertions, 34 deletions

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 2e947a485898..6fee4a7e88d7 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6389,8 +6389,6 @@ void perf_event_wakeup(struct perf_event *event)
 
 static void perf_sigtrap(struct perf_event *event)
 {
-	struct kernel_siginfo info;
-
 	/*
 	 * We'd expect this to only occur if the irq_work is delayed and either
 	 * ctx->task or current has changed in the meantime. This can be the
@@ -6405,13 +6403,8 @@ static void perf_sigtrap(struct perf_event *event)
 	if (current->flags & PF_EXITING)
 		return;
 
-	clear_siginfo(&info);
-	info.si_signo = SIGTRAP;
-	info.si_code = TRAP_PERF;
-	info.si_errno = event->attr.type;
-	info.si_perf = event->attr.sig_data;
-	info.si_addr = (void __user *)event->pending_addr;
-	force_sig_info(&info);
+	force_sig_perf((void __user *)event->pending_addr,
+		       event->attr.type, event->attr.sig_data);
 }
 
 static void perf_pending_event_disable(struct perf_event *event)
diff --git a/kernel/signal.c b/kernel/signal.c
index 66e88649cf74..f7c6ffcbd044 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1236,6 +1236,7 @@ static inline bool has_si_pid_and_uid(struct kernel_siginfo *info)
 	case SIL_TIMER:
 	case SIL_POLL:
 	case SIL_FAULT:
+	case SIL_FAULT_TRAPNO:
 	case SIL_FAULT_MCEERR:
 	case SIL_FAULT_BNDERR:
 	case SIL_FAULT_PKUERR:
@@ -1804,6 +1805,21 @@ int force_sig_pkuerr(void __user *addr, u32 pkey)
 }
 #endif
 
+int force_sig_perf(void __user *addr, u32 type, u64 sig_data)
+{
+	struct kernel_siginfo info;
+
+	clear_siginfo(&info);
+	info.si_signo     = SIGTRAP;
+	info.si_errno     = 0;
+	info.si_code      = TRAP_PERF;
+	info.si_addr      = addr;
+	info.si_perf_data = sig_data;
+	info.si_perf_type = type;
+
+	return force_sig_info(&info);
+}
+
 /* For the crazy architectures that include trap information in
  * the errno field, instead of an actual errno value.
  */
@@ -2564,6 +2580,7 @@ static void hide_si_addr_tag_bits(struct ksignal *ksig)
 {
 	switch (siginfo_layout(ksig->sig, ksig->info.si_code)) {
 	case SIL_FAULT:
+	case SIL_FAULT_TRAPNO:
 	case SIL_FAULT_MCEERR:
 	case SIL_FAULT_BNDERR:
 	case SIL_FAULT_PKUERR:
@@ -3251,6 +3268,10 @@ enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
 #endif
 			else if ((sig == SIGTRAP) && (si_code == TRAP_PERF))
 				layout = SIL_PERF_EVENT;
+#ifdef __ARCH_SI_TRAPNO
+			else if (layout == SIL_FAULT)
+				layout = SIL_FAULT_TRAPNO;
+#endif
 		}
 		else if (si_code <= NSIGPOLL)
 			layout = SIL_POLL;
@@ -3354,35 +3375,28 @@ void copy_siginfo_to_external32(struct compat_siginfo *to,
 		break;
 	case SIL_FAULT:
 		to->si_addr = ptr_to_compat(from->si_addr);
-#ifdef __ARCH_SI_TRAPNO
+		break;
+	case SIL_FAULT_TRAPNO:
+		to->si_addr = ptr_to_compat(from->si_addr);
 		to->si_trapno = from->si_trapno;
-#endif
 		break;
 	case SIL_FAULT_MCEERR:
 		to->si_addr = ptr_to_compat(from->si_addr);
-#ifdef __ARCH_SI_TRAPNO
-		to->si_trapno = from->si_trapno;
-#endif
 		to->si_addr_lsb = from->si_addr_lsb;
 		break;
 	case SIL_FAULT_BNDERR:
 		to->si_addr = ptr_to_compat(from->si_addr);
-#ifdef __ARCH_SI_TRAPNO
-		to->si_trapno = from->si_trapno;
-#endif
 		to->si_lower = ptr_to_compat(from->si_lower);
 		to->si_upper = ptr_to_compat(from->si_upper);
 		break;
 	case SIL_FAULT_PKUERR:
 		to->si_addr = ptr_to_compat(from->si_addr);
-#ifdef __ARCH_SI_TRAPNO
-		to->si_trapno = from->si_trapno;
-#endif
 		to->si_pkey = from->si_pkey;
 		break;
 	case SIL_PERF_EVENT:
 		to->si_addr = ptr_to_compat(from->si_addr);
-		to->si_perf = from->si_perf;
+		to->si_perf_data = from->si_perf_data;
+		to->si_perf_type = from->si_perf_type;
 		break;
 	case SIL_CHLD:
 		to->si_pid = from->si_pid;
@@ -3438,35 +3452,28 @@ static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
 		break;
 	case SIL_FAULT:
 		to->si_addr = compat_ptr(from->si_addr);
-#ifdef __ARCH_SI_TRAPNO
+		break;
+	case SIL_FAULT_TRAPNO:
+		to->si_addr = compat_ptr(from->si_addr);
 		to->si_trapno = from->si_trapno;
-#endif
 		break;
 	case SIL_FAULT_MCEERR:
 		to->si_addr = compat_ptr(from->si_addr);
-#ifdef __ARCH_SI_TRAPNO
-		to->si_trapno = from->si_trapno;
-#endif
 		to->si_addr_lsb = from->si_addr_lsb;
 		break;
 	case SIL_FAULT_BNDERR:
 		to->si_addr = compat_ptr(from->si_addr);
-#ifdef __ARCH_SI_TRAPNO
-		to->si_trapno = from->si_trapno;
-#endif
 		to->si_lower = compat_ptr(from->si_lower);
 		to->si_upper = compat_ptr(from->si_upper);
 		break;
 	case SIL_FAULT_PKUERR:
 		to->si_addr = compat_ptr(from->si_addr);
-#ifdef __ARCH_SI_TRAPNO
-		to->si_trapno = from->si_trapno;
-#endif
 		to->si_pkey = from->si_pkey;
 		break;
 	case SIL_PERF_EVENT:
 		to->si_addr = compat_ptr(from->si_addr);
-		to->si_perf = from->si_perf;
+		to->si_perf_data = from->si_perf_data;
+		to->si_perf_type = from->si_perf_type;
 		break;
 	case SIL_CHLD:
 		to->si_pid    = from->si_pid;
@@ -4644,11 +4651,13 @@ static inline void siginfo_buildtime_checks(void)
 
 	/* sigfault */
 	CHECK_OFFSET(si_addr);
+	CHECK_OFFSET(si_trapno);
 	CHECK_OFFSET(si_addr_lsb);
 	CHECK_OFFSET(si_lower);
 	CHECK_OFFSET(si_upper);
 	CHECK_OFFSET(si_pkey);
-	CHECK_OFFSET(si_perf);
+	CHECK_OFFSET(si_perf_data);
+	CHECK_OFFSET(si_perf_type);
 
 	/* sigpoll */
 	CHECK_OFFSET(si_band);