Final si_trapno bits

As a part of a fix for the ABI of the newly added SIGTRAP TRAP_PERF a
si_trapno was reduced to an ordinary extention of the _sigfault case
of struct siginfo.

When Linus saw the complete set of changes come in as a fix he requested
that the set of changes be trimmed down to just what was necessary to
fix the SIGTRAP TRAP_PERF ABI.

I had intended to get the rest of the changes into the merge window for
v5.14 but I dropped the ball.

I have made the changes to stop using __ARCH_SI_TRAPNO be per
architecture so they are easier to review.  In doing so I found one
place on alpha where I used send_sig_fault instead of
send_sig_fault_trapno(... si_trapno = 0).  That would not have changed
the userspace behavior but it did make the kernel code less clear.

My rule in these patches is everywhere that siginfo layout calls
for SIL_FAULT_TRAPNO the code uses either force_sig_fault_trapno
or send_sig_fault_trapno.

And of course I have rebased and compile tested Marco's compile time
assert patches.

v1: https://lkml.kernel.org/r/m1zgxfs7zq.fsf_-_@fess.ebiederm.org
v2: https://lkml.kernel.org/r/m14kfjh8et.fsf_-_@fess.ebiederm.org
v3: https://lkml.kernel.org/r/m1tuni8ano.fsf_-_@fess.ebiederm.org
v4: https://lkml.kernel.org/r/m1a6ot5e2h.fsf_-_@fess.ebiederm.org
Link: https://lkml.kernel.org/r/87a6mnzbx2.fsf_-_@disp2133

Eric W. Biederman (5):
      signal/sparc: si_trapno is only used with SIGILL ILL_ILLTRP
      signal/alpha: si_trapno is only used with SIGFPE and SIGTRAP TRAP_UNK
      signal: Remove the generic __ARCH_SI_TRAPNO support
      signal: Verify the alignment and size of siginfo_t
      signal: Rename SIL_PERF_EVENT SIL_FAULT_PERF_EVENT for consistency

Marco Elver (3):
      sparc64: Add compile-time asserts for siginfo_t offsets
      arm: Add compile-time asserts for siginfo_t offsets
      arm64: Add compile-time asserts for siginfo_t offsets

 arch/alpha/include/uapi/asm/siginfo.h |  2 --
 arch/alpha/kernel/osf_sys.c           |  2 +-
 arch/alpha/kernel/signal.c            |  4 +--
 arch/alpha/kernel/traps.c             | 26 +++++++--------
 arch/alpha/mm/fault.c                 |  4 +--
 arch/arm/kernel/signal.c              | 39 ++++++++++++++++++++++
 arch/arm64/kernel/signal.c            | 39 ++++++++++++++++++++++
 arch/arm64/kernel/signal32.c          | 39 ++++++++++++++++++++++
 arch/mips/include/uapi/asm/siginfo.h  |  2 --
 arch/sparc/include/uapi/asm/siginfo.h |  3 --
 arch/sparc/kernel/process_64.c        |  2 +-
 arch/sparc/kernel/signal32.c          | 37 +++++++++++++++++++++
 arch/sparc/kernel/signal_64.c         | 36 ++++++++++++++++++++
 arch/sparc/kernel/sys_sparc_32.c      |  2 +-
 arch/sparc/kernel/sys_sparc_64.c      |  2 +-
 arch/sparc/kernel/traps_32.c          | 22 ++++++-------
 arch/sparc/kernel/traps_64.c          | 44 +++++++++++--------------
 arch/sparc/kernel/unaligned_32.c      |  2 +-
 arch/sparc/mm/fault_32.c              |  2 +-
 arch/sparc/mm/fault_64.c              |  2 +-
 arch/x86/kernel/signal_compat.c       |  6 ++++
 fs/signalfd.c                         |  4 +--
 include/linux/sched/signal.h          | 11 ++-----
 include/linux/signal.h                |  2 +-
 include/uapi/asm-generic/siginfo.h    |  5 +++
 kernel/signal.c                       | 62 +++++++++++++++++++++++++----------
 26 files changed, 305 insertions(+), 96 deletions(-)

21 files changed, 250 insertions, 67 deletions

diff --git a/arch/alpha/include/uapi/asm/siginfo.h b/arch/alpha/include/uapi/asm/siginfo.h
index 6e1a2af2f962..e08eae88182b 100644
--- a/arch/alpha/include/uapi/asm/siginfo.h
+++ b/arch/alpha/include/uapi/asm/siginfo.h
@@ -2,8 +2,6 @@
 #ifndef _ALPHA_SIGINFO_H
 #define _ALPHA_SIGINFO_H
 
-#define __ARCH_SI_TRAPNO
-
 #include <asm-generic/siginfo.h>
 
 #endif
diff --git a/arch/alpha/kernel/osf_sys.c b/arch/alpha/kernel/osf_sys.c
index d5367a1c6300..bbdb1a9a5fd8 100644
--- a/arch/alpha/kernel/osf_sys.c
+++ b/arch/alpha/kernel/osf_sys.c
@@ -876,7 +876,7 @@ SYSCALL_DEFINE5(osf_setsysinfo, unsigned long, op, void __user *, buffer,
 			if (fex & IEEE_TRAP_ENABLE_DZE) si_code = FPE_FLTDIV;
 			if (fex & IEEE_TRAP_ENABLE_INV) si_code = FPE_FLTINV;
 
-			send_sig_fault(SIGFPE, si_code,
+			send_sig_fault_trapno(SIGFPE, si_code,
 				       (void __user *)NULL,  /* FIXME */
 				       0, current);
  		}
diff --git a/arch/alpha/kernel/signal.c b/arch/alpha/kernel/signal.c
index 948b89789da8..bc077babafab 100644
--- a/arch/alpha/kernel/signal.c
+++ b/arch/alpha/kernel/signal.c
@@ -219,7 +219,7 @@ do_sigreturn(struct sigcontext __user *sc)
 
 	/* Send SIGTRAP if we're single-stepping: */
 	if (ptrace_cancel_bpt (current)) {
-		send_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *) regs->pc, 0,
+		send_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *) regs->pc,
 			       current);
 	}
 	return;
@@ -247,7 +247,7 @@ do_rt_sigreturn(struct rt_sigframe __user *frame)
 
 	/* Send SIGTRAP if we're single-stepping: */
 	if (ptrace_cancel_bpt (current)) {
-		send_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *) regs->pc, 0,
+		send_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *) regs->pc,
 			       current);
 	}
 	return;
diff --git a/arch/alpha/kernel/traps.c b/arch/alpha/kernel/traps.c
index 921d4b6e4d95..e9e3de18793b 100644
--- a/arch/alpha/kernel/traps.c
+++ b/arch/alpha/kernel/traps.c
@@ -227,7 +227,7 @@ do_entArith(unsigned long summary, unsigned long write_mask,
 	}
 	die_if_kernel("Arithmetic fault", regs, 0, NULL);
 
-	send_sig_fault(SIGFPE, si_code, (void __user *) regs->pc, 0, current);
+	send_sig_fault_trapno(SIGFPE, si_code, (void __user *) regs->pc, 0, current);
 }
 
 asmlinkage void
@@ -268,13 +268,13 @@ do_entIF(unsigned long type, struct pt_regs *regs)
 			regs->pc -= 4;	/* make pc point to former bpt */
 		}
 
-		send_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->pc, 0,
+		send_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->pc,
 			       current);
 		return;
 
 	      case 1: /* bugcheck */
-		send_sig_fault(SIGTRAP, TRAP_UNK, (void __user *) regs->pc, 0,
-			       current);
+		send_sig_fault_trapno(SIGTRAP, TRAP_UNK,
+				      (void __user *) regs->pc, 0, current);
 		return;
 		
 	      case 2: /* gentrap */
@@ -335,8 +335,8 @@ do_entIF(unsigned long type, struct pt_regs *regs)
 			break;
 		}
 
-		send_sig_fault(signo, code, (void __user *) regs->pc, regs->r16,
-			       current);
+		send_sig_fault_trapno(signo, code, (void __user *) regs->pc,
+				      regs->r16, current);
 		return;
 
 	      case 4: /* opDEC */
@@ -360,9 +360,9 @@ do_entIF(unsigned long type, struct pt_regs *regs)
 			if (si_code == 0)
 				return;
 			if (si_code > 0) {
-				send_sig_fault(SIGFPE, si_code,
-					       (void __user *) regs->pc, 0,
-					       current);
+				send_sig_fault_trapno(SIGFPE, si_code,
+						      (void __user *) regs->pc,
+						      0, current);
 				return;
 			}
 		}
@@ -387,7 +387,7 @@ do_entIF(unsigned long type, struct pt_regs *regs)
 		      ;
 	}
 
-	send_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)regs->pc, 0, current);
+	send_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)regs->pc, current);
 }
 
 /* There is an ifdef in the PALcode in MILO that enables a 
@@ -402,7 +402,7 @@ do_entDbg(struct pt_regs *regs)
 {
 	die_if_kernel("Instruction fault", regs, 0, NULL);
 
-	force_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)regs->pc, 0);
+	force_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)regs->pc);
 }
 
 
@@ -964,12 +964,12 @@ give_sigsegv:
 			si_code = SEGV_MAPERR;
 		mmap_read_unlock(mm);
 	}
-	send_sig_fault(SIGSEGV, si_code, va, 0, current);
+	send_sig_fault(SIGSEGV, si_code, va, current);
 	return;
 
 give_sigbus:
 	regs->pc -= 4;
-	send_sig_fault(SIGBUS, BUS_ADRALN, va, 0, current);
+	send_sig_fault(SIGBUS, BUS_ADRALN, va, current);
 	return;
 }
 
diff --git a/arch/alpha/mm/fault.c b/arch/alpha/mm/fault.c
index 09172f017efc..eee5102c3d88 100644
--- a/arch/alpha/mm/fault.c
+++ b/arch/alpha/mm/fault.c
@@ -219,13 +219,13 @@ retry:
 	mmap_read_unlock(mm);
 	/* Send a sigbus, regardless of whether we were in kernel
 	   or user mode.  */
-	force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *) address, 0);
+	force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *) address);
 	if (!user_mode(regs))
 		goto no_context;
 	return;
 
  do_sigsegv:
-	force_sig_fault(SIGSEGV, si_code, (void __user *) address, 0);
+	force_sig_fault(SIGSEGV, si_code, (void __user *) address);
 	return;
 
 #ifdef CONFIG_ALPHA_LARGE_VMALLOC
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index a3a38d0a4c85..f3800c0f428b 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -725,3 +725,42 @@ asmlinkage void do_rseq_syscall(struct pt_regs *regs)
 	rseq_syscall(regs);
 }
 #endif
+
+/*
+ * Compile-time assertions for siginfo_t offsets. Check NSIG* as well, as
+ * changes likely come with new fields that should be added below.
+ */
+static_assert(NSIGILL	== 11);
+static_assert(NSIGFPE	== 15);
+static_assert(NSIGSEGV	== 9);
+static_assert(NSIGBUS	== 5);
+static_assert(NSIGTRAP	== 6);
+static_assert(NSIGCHLD	== 6);
+static_assert(NSIGSYS	== 2);
+static_assert(sizeof(siginfo_t) == 128);
+static_assert(__alignof__(siginfo_t) == 4);
+static_assert(offsetof(siginfo_t, si_signo)	== 0x00);
+static_assert(offsetof(siginfo_t, si_errno)	== 0x04);
+static_assert(offsetof(siginfo_t, si_code)	== 0x08);
+static_assert(offsetof(siginfo_t, si_pid)	== 0x0c);
+static_assert(offsetof(siginfo_t, si_uid)	== 0x10);
+static_assert(offsetof(siginfo_t, si_tid)	== 0x0c);
+static_assert(offsetof(siginfo_t, si_overrun)	== 0x10);
+static_assert(offsetof(siginfo_t, si_status)	== 0x14);
+static_assert(offsetof(siginfo_t, si_utime)	== 0x18);
+static_assert(offsetof(siginfo_t, si_stime)	== 0x1c);
+static_assert(offsetof(siginfo_t, si_value)	== 0x14);
+static_assert(offsetof(siginfo_t, si_int)	== 0x14);
+static_assert(offsetof(siginfo_t, si_ptr)	== 0x14);
+static_assert(offsetof(siginfo_t, si_addr)	== 0x0c);
+static_assert(offsetof(siginfo_t, si_addr_lsb)	== 0x10);
+static_assert(offsetof(siginfo_t, si_lower)	== 0x14);
+static_assert(offsetof(siginfo_t, si_upper)	== 0x18);
+static_assert(offsetof(siginfo_t, si_pkey)	== 0x14);
+static_assert(offsetof(siginfo_t, si_perf_data)	== 0x10);
+static_assert(offsetof(siginfo_t, si_perf_type)	== 0x14);
+static_assert(offsetof(siginfo_t, si_band)	== 0x0c);
+static_assert(offsetof(siginfo_t, si_fd)	== 0x10);
+static_assert(offsetof(siginfo_t, si_call_addr)	== 0x0c);
+static_assert(offsetof(siginfo_t, si_syscall)	== 0x10);
+static_assert(offsetof(siginfo_t, si_arch)	== 0x14);
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index f8192f4ae0b8..d3721e01441b 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -999,3 +999,42 @@ void __init minsigstksz_setup(void)
 		round_up(sizeof(struct frame_record), 16) +
 		16; /* max alignment padding */
 }
+
+/*
+ * Compile-time assertions for siginfo_t offsets. Check NSIG* as well, as
+ * changes likely come with new fields that should be added below.
+ */
+static_assert(NSIGILL	== 11);
+static_assert(NSIGFPE	== 15);
+static_assert(NSIGSEGV	== 9);
+static_assert(NSIGBUS	== 5);
+static_assert(NSIGTRAP	== 6);
+static_assert(NSIGCHLD	== 6);
+static_assert(NSIGSYS	== 2);
+static_assert(sizeof(siginfo_t) == 128);
+static_assert(__alignof__(siginfo_t) == 8);
+static_assert(offsetof(siginfo_t, si_signo)	== 0x00);
+static_assert(offsetof(siginfo_t, si_errno)	== 0x04);
+static_assert(offsetof(siginfo_t, si_code)	== 0x08);
+static_assert(offsetof(siginfo_t, si_pid)	== 0x10);
+static_assert(offsetof(siginfo_t, si_uid)	== 0x14);
+static_assert(offsetof(siginfo_t, si_tid)	== 0x10);
+static_assert(offsetof(siginfo_t, si_overrun)	== 0x14);
+static_assert(offsetof(siginfo_t, si_status)	== 0x18);
+static_assert(offsetof(siginfo_t, si_utime)	== 0x20);
+static_assert(offsetof(siginfo_t, si_stime)	== 0x28);
+static_assert(offsetof(siginfo_t, si_value)	== 0x18);
+static_assert(offsetof(siginfo_t, si_int)	== 0x18);
+static_assert(offsetof(siginfo_t, si_ptr)	== 0x18);
+static_assert(offsetof(siginfo_t, si_addr)	== 0x10);
+static_assert(offsetof(siginfo_t, si_addr_lsb)	== 0x18);
+static_assert(offsetof(siginfo_t, si_lower)	== 0x20);
+static_assert(offsetof(siginfo_t, si_upper)	== 0x28);
+static_assert(offsetof(siginfo_t, si_pkey)	== 0x20);
+static_assert(offsetof(siginfo_t, si_perf_data)	== 0x18);
+static_assert(offsetof(siginfo_t, si_perf_type)	== 0x20);
+static_assert(offsetof(siginfo_t, si_band)	== 0x10);
+static_assert(offsetof(siginfo_t, si_fd)	== 0x18);
+static_assert(offsetof(siginfo_t, si_call_addr)	== 0x10);
+static_assert(offsetof(siginfo_t, si_syscall)	== 0x18);
+static_assert(offsetof(siginfo_t, si_arch)	== 0x1c);
diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c
index 2f507f565c48..d3be01c46bec 100644
--- a/arch/arm64/kernel/signal32.c
+++ b/arch/arm64/kernel/signal32.c
@@ -457,3 +457,42 @@ void compat_setup_restart_syscall(struct pt_regs *regs)
 {
        regs->regs[7] = __NR_compat_restart_syscall;
 }
+
+/*
+ * Compile-time assertions for siginfo_t offsets. Check NSIG* as well, as
+ * changes likely come with new fields that should be added below.
+ */
+static_assert(NSIGILL	== 11);
+static_assert(NSIGFPE	== 15);
+static_assert(NSIGSEGV	== 9);
+static_assert(NSIGBUS	== 5);
+static_assert(NSIGTRAP	== 6);
+static_assert(NSIGCHLD	== 6);
+static_assert(NSIGSYS	== 2);
+static_assert(sizeof(compat_siginfo_t) == 128);
+static_assert(__alignof__(compat_siginfo_t) == 4);
+static_assert(offsetof(compat_siginfo_t, si_signo)	== 0x00);
+static_assert(offsetof(compat_siginfo_t, si_errno)	== 0x04);
+static_assert(offsetof(compat_siginfo_t, si_code)	== 0x08);
+static_assert(offsetof(compat_siginfo_t, si_pid)	== 0x0c);
+static_assert(offsetof(compat_siginfo_t, si_uid)	== 0x10);
+static_assert(offsetof(compat_siginfo_t, si_tid)	== 0x0c);
+static_assert(offsetof(compat_siginfo_t, si_overrun)	== 0x10);
+static_assert(offsetof(compat_siginfo_t, si_status)	== 0x14);
+static_assert(offsetof(compat_siginfo_t, si_utime)	== 0x18);
+static_assert(offsetof(compat_siginfo_t, si_stime)	== 0x1c);
+static_assert(offsetof(compat_siginfo_t, si_value)	== 0x14);
+static_assert(offsetof(compat_siginfo_t, si_int)	== 0x14);
+static_assert(offsetof(compat_siginfo_t, si_ptr)	== 0x14);
+static_assert(offsetof(compat_siginfo_t, si_addr)	== 0x0c);
+static_assert(offsetof(compat_siginfo_t, si_addr_lsb)	== 0x10);
+static_assert(offsetof(compat_siginfo_t, si_lower)	== 0x14);
+static_assert(offsetof(compat_siginfo_t, si_upper)	== 0x18);
+static_assert(offsetof(compat_siginfo_t, si_pkey)	== 0x14);
+static_assert(offsetof(compat_siginfo_t, si_perf_data)	== 0x10);
+static_assert(offsetof(compat_siginfo_t, si_perf_type)	== 0x14);
+static_assert(offsetof(compat_siginfo_t, si_band)	== 0x0c);
+static_assert(offsetof(compat_siginfo_t, si_fd)		== 0x10);
+static_assert(offsetof(compat_siginfo_t, si_call_addr)	== 0x0c);
+static_assert(offsetof(compat_siginfo_t, si_syscall)	== 0x10);
+static_assert(offsetof(compat_siginfo_t, si_arch)	== 0x14);
diff --git a/arch/mips/include/uapi/asm/siginfo.h b/arch/mips/include/uapi/asm/siginfo.h
index c34c7eef0a1c..8cb8bd061a68 100644
--- a/arch/mips/include/uapi/asm/siginfo.h
+++ b/arch/mips/include/uapi/asm/siginfo.h
@@ -10,9 +10,7 @@
 #ifndef _UAPI_ASM_SIGINFO_H
 #define _UAPI_ASM_SIGINFO_H
 
-
 #define __ARCH_SIGEV_PREAMBLE_SIZE (sizeof(long) + 2*sizeof(int))
-#undef __ARCH_SI_TRAPNO /* exception code needs to fill this ...  */
 
 #define __ARCH_HAS_SWAPPED_SIGINFO
 
diff --git a/arch/sparc/include/uapi/asm/siginfo.h b/arch/sparc/include/uapi/asm/siginfo.h
index 68bdde4c2a2e..0e7c27522aed 100644
--- a/arch/sparc/include/uapi/asm/siginfo.h
+++ b/arch/sparc/include/uapi/asm/siginfo.h
@@ -8,9 +8,6 @@
 
 #endif /* defined(__sparc__) && defined(__arch64__) */
 
-
-#define __ARCH_SI_TRAPNO
-
 #include <asm-generic/siginfo.h>
 
 
diff --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c
index d33c58a58d4f..547b06b49ce3 100644
--- a/arch/sparc/kernel/process_64.c
+++ b/arch/sparc/kernel/process_64.c
@@ -518,7 +518,7 @@ void synchronize_user_stack(void)
 
 static void stack_unaligned(unsigned long sp)
 {
-	force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *) sp, 0);
+	force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *) sp);
 }
 
 static const char uwfault32[] = KERN_INFO \
diff --git a/arch/sparc/kernel/signal32.c b/arch/sparc/kernel/signal32.c
index e9695a06492f..4276b9e003ca 100644
--- a/arch/sparc/kernel/signal32.c
+++ b/arch/sparc/kernel/signal32.c
@@ -745,3 +745,40 @@ asmlinkage int do_sys32_sigstack(u32 u_ssptr, u32 u_ossptr, unsigned long sp)
 out:
 	return ret;
 }
+
+/*
+ * Compile-time assertions for siginfo_t offsets. Check NSIG* as well, as
+ * changes likely come with new fields that should be added below.
+ */
+static_assert(NSIGILL	== 11);
+static_assert(NSIGFPE	== 15);
+static_assert(NSIGSEGV	== 9);
+static_assert(NSIGBUS	== 5);
+static_assert(NSIGTRAP	== 6);
+static_assert(NSIGCHLD	== 6);
+static_assert(NSIGSYS	== 2);
+static_assert(sizeof(compat_siginfo_t) == 128);
+static_assert(__alignof__(compat_siginfo_t) == 4);
+static_assert(offsetof(compat_siginfo_t, si_signo)	== 0x00);
+static_assert(offsetof(compat_siginfo_t, si_errno)	== 0x04);
+static_assert(offsetof(compat_siginfo_t, si_code)	== 0x08);
+static_assert(offsetof(compat_siginfo_t, si_pid)	== 0x0c);
+static_assert(offsetof(compat_siginfo_t, si_uid)	== 0x10);
+static_assert(offsetof(compat_siginfo_t, si_tid)	== 0x0c);
+static_assert(offsetof(compat_siginfo_t, si_overrun)	== 0x10);
+static_assert(offsetof(compat_siginfo_t, si_status)	== 0x14);
+static_assert(offsetof(compat_siginfo_t, si_utime)	== 0x18);
+static_assert(offsetof(compat_siginfo_t, si_stime)	== 0x1c);
+static_assert(offsetof(compat_siginfo_t, si_value)	== 0x14);
+static_assert(offsetof(compat_siginfo_t, si_int)	== 0x14);
+static_assert(offsetof(compat_siginfo_t, si_ptr)	== 0x14);
+static_assert(offsetof(compat_siginfo_t, si_addr)	== 0x0c);
+static_assert(offsetof(compat_siginfo_t, si_trapno)	== 0x10);
+static_assert(offsetof(compat_siginfo_t, si_addr_lsb)	== 0x10);
+static_assert(offsetof(compat_siginfo_t, si_lower)	== 0x14);
+static_assert(offsetof(compat_siginfo_t, si_upper)	== 0x18);
+static_assert(offsetof(compat_siginfo_t, si_pkey)	== 0x14);
+static_assert(offsetof(compat_siginfo_t, si_perf_data)	== 0x10);
+static_assert(offsetof(compat_siginfo_t, si_perf_type)	== 0x14);
+static_assert(offsetof(compat_siginfo_t, si_band)	== 0x0c);
+static_assert(offsetof(compat_siginfo_t, si_fd)		== 0x10);
diff --git a/arch/sparc/kernel/signal_64.c b/arch/sparc/kernel/signal_64.c
index a0eec62c825d..cea23cf95600 100644
--- a/arch/sparc/kernel/signal_64.c
+++ b/arch/sparc/kernel/signal_64.c
@@ -556,3 +556,39 @@ void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, unsigned long
 	user_enter();
 }
 
+/*
+ * Compile-time assertions for siginfo_t offsets. Check NSIG* as well, as
+ * changes likely come with new fields that should be added below.
+ */
+static_assert(NSIGILL	== 11);
+static_assert(NSIGFPE	== 15);
+static_assert(NSIGSEGV	== 9);
+static_assert(NSIGBUS	== 5);
+static_assert(NSIGTRAP	== 6);
+static_assert(NSIGCHLD	== 6);
+static_assert(NSIGSYS	== 2);
+static_assert(sizeof(siginfo_t) == 128);
+static_assert(__alignof__(siginfo_t) == 8);
+static_assert(offsetof(siginfo_t, si_signo)	== 0x00);
+static_assert(offsetof(siginfo_t, si_errno)	== 0x04);
+static_assert(offsetof(siginfo_t, si_code)	== 0x08);
+static_assert(offsetof(siginfo_t, si_pid)	== 0x10);
+static_assert(offsetof(siginfo_t, si_uid)	== 0x14);
+static_assert(offsetof(siginfo_t, si_tid)	== 0x10);
+static_assert(offsetof(siginfo_t, si_overrun)	== 0x14);
+static_assert(offsetof(siginfo_t, si_status)	== 0x18);
+static_assert(offsetof(siginfo_t, si_utime)	== 0x20);
+static_assert(offsetof(siginfo_t, si_stime)	== 0x28);
+static_assert(offsetof(siginfo_t, si_value)	== 0x18);
+static_assert(offsetof(siginfo_t, si_int)	== 0x18);
+static_assert(offsetof(siginfo_t, si_ptr)	== 0x18);
+static_assert(offsetof(siginfo_t, si_addr)	== 0x10);
+static_assert(offsetof(siginfo_t, si_trapno)	== 0x18);
+static_assert(offsetof(siginfo_t, si_addr_lsb)	== 0x18);
+static_assert(offsetof(siginfo_t, si_lower)	== 0x20);
+static_assert(offsetof(siginfo_t, si_upper)	== 0x28);
+static_assert(offsetof(siginfo_t, si_pkey)	== 0x20);
+static_assert(offsetof(siginfo_t, si_perf_data)	== 0x18);
+static_assert(offsetof(siginfo_t, si_perf_type)	== 0x20);
+static_assert(offsetof(siginfo_t, si_band)	== 0x10);
+static_assert(offsetof(siginfo_t, si_fd)	== 0x14);
diff --git a/arch/sparc/kernel/sys_sparc_32.c b/arch/sparc/kernel/sys_sparc_32.c
index be77538bc038..082a551897ed 100644
--- a/arch/sparc/kernel/sys_sparc_32.c
+++ b/arch/sparc/kernel/sys_sparc_32.c
@@ -151,7 +151,7 @@ sparc_breakpoint (struct pt_regs *regs)
 #ifdef DEBUG_SPARC_BREAKPOINT
         printk ("TRAP: Entering kernel PC=%x, nPC=%x\n", regs->pc, regs->npc);
 #endif
-	force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->pc, 0);
+	force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->pc);
 
 #ifdef DEBUG_SPARC_BREAKPOINT
 	printk ("TRAP: Returning to space: PC=%x nPC=%x\n", regs->pc, regs->npc);
diff --git a/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c
index 6b92fadb6ec7..1e9a9e016237 100644
--- a/arch/sparc/kernel/sys_sparc_64.c
+++ b/arch/sparc/kernel/sys_sparc_64.c
@@ -514,7 +514,7 @@ asmlinkage void sparc_breakpoint(struct pt_regs *regs)
 #ifdef DEBUG_SPARC_BREAKPOINT
         printk ("TRAP: Entering kernel PC=%lx, nPC=%lx\n", regs->tpc, regs->tnpc);
 #endif
-	force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->tpc, 0);
+	force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->tpc);
 #ifdef DEBUG_SPARC_BREAKPOINT
 	printk ("TRAP: Returning to space: PC=%lx nPC=%lx\n", regs->tpc, regs->tnpc);
 #endif
diff --git a/arch/sparc/kernel/traps_32.c b/arch/sparc/kernel/traps_32.c
index 247a0d9683b2..5630e5a395e0 100644
--- a/arch/sparc/kernel/traps_32.c
+++ b/arch/sparc/kernel/traps_32.c
@@ -102,8 +102,8 @@ void do_hw_interrupt(struct pt_regs *regs, unsigned long type)
 	if(regs->psr & PSR_PS)
 		die_if_kernel("Kernel bad trap", regs);
 
-	force_sig_fault(SIGILL, ILL_ILLTRP,
-			(void __user *)regs->pc, type - 0x80);
+	force_sig_fault_trapno(SIGILL, ILL_ILLTRP,
+			       (void __user *)regs->pc, type - 0x80);
 }
 
 void do_illegal_instruction(struct pt_regs *regs, unsigned long pc, unsigned long npc,
@@ -116,7 +116,7 @@ void do_illegal_instruction(struct pt_regs *regs, unsigned long pc, unsigned lon
 	       regs->pc, *(unsigned long *)regs->pc);
 #endif
 
-	send_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)pc, 0, current);
+	send_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)pc, current);
 }
 
 void do_priv_instruction(struct pt_regs *regs, unsigned long pc, unsigned long npc,
@@ -124,7 +124,7 @@ void do_priv_instruction(struct pt_regs *regs, unsigned long pc, unsigned long n
 {
 	if(psr & PSR_PS)
 		die_if_kernel("Penguin instruction from Penguin mode??!?!", regs);
-	send_sig_fault(SIGILL, ILL_PRVOPC, (void __user *)pc, 0, current);
+	send_sig_fault(SIGILL, ILL_PRVOPC, (void __user *)pc, current);
 }
 
 /* XXX User may want to be allowed to do this. XXX */
@@ -145,7 +145,7 @@ void do_memaccess_unaligned(struct pt_regs *regs, unsigned long pc, unsigned lon
 #endif
 	send_sig_fault(SIGBUS, BUS_ADRALN,
 		       /* FIXME: Should dig out mna address */ (void *)0,
-		       0, current);
+		       current);
 }
 
 static unsigned long init_fsr = 0x0UL;
@@ -291,7 +291,7 @@ void do_fpe_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 		else if (fsr & 0x01)
 			code = FPE_FLTRES;
 	}
-	send_sig_fault(SIGFPE, code, (void __user *)pc, 0, fpt);
+	send_sig_fault(SIGFPE, code, (void __user *)pc, fpt);
 #ifndef CONFIG_SMP
 	last_task_used_math = NULL;
 #endif
@@ -305,7 +305,7 @@ void handle_tag_overflow(struct pt_regs *regs, unsigned long pc, unsigned long n
 {
 	if(psr & PSR_PS)
 		die_if_kernel("Penguin overflow trap from kernel mode", regs);
-	send_sig_fault(SIGEMT, EMT_TAGOVF, (void __user *)pc, 0, current);
+	send_sig_fault(SIGEMT, EMT_TAGOVF, (void __user *)pc, current);
 }
 
 void handle_watchpoint(struct pt_regs *regs, unsigned long pc, unsigned long npc,
@@ -327,13 +327,13 @@ void handle_reg_access(struct pt_regs *regs, unsigned long pc, unsigned long npc
 	printk("Register Access Exception at PC %08lx NPC %08lx PSR %08lx\n",
 	       pc, npc, psr);
 #endif
-	force_sig_fault(SIGBUS, BUS_OBJERR, (void __user *)pc, 0);
+	force_sig_fault(SIGBUS, BUS_OBJERR, (void __user *)pc);
 }
 
 void handle_cp_disabled(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 			unsigned long psr)
 {
-	send_sig_fault(SIGILL, ILL_COPROC, (void __user *)pc, 0, current);
+	send_sig_fault(SIGILL, ILL_COPROC, (void __user *)pc, current);
 }
 
 void handle_cp_exception(struct pt_regs *regs, unsigned long pc, unsigned long npc,
@@ -343,13 +343,13 @@ void handle_cp_exception(struct pt_regs *regs, unsigned long pc, unsigned long n
 	printk("Co-Processor Exception at PC %08lx NPC %08lx PSR %08lx\n",
 	       pc, npc, psr);
 #endif
-	send_sig_fault(SIGILL, ILL_COPROC, (void __user *)pc, 0, current);
+	send_sig_fault(SIGILL, ILL_COPROC, (void __user *)pc, current);
 }
 
 void handle_hw_divzero(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 		       unsigned long psr)
 {
-	send_sig_fault(SIGFPE, FPE_INTDIV, (void __user *)pc, 0, current);
+	send_sig_fault(SIGFPE, FPE_INTDIV, (void __user *)pc, current);
 }
 
 #ifdef CONFIG_DEBUG_BUGVERBOSE
diff --git a/arch/sparc/kernel/traps_64.c b/arch/sparc/kernel/traps_64.c
index a850dccd78ea..6863025ed56d 100644
--- a/arch/sparc/kernel/traps_64.c
+++ b/arch/sparc/kernel/traps_64.c
@@ -107,8 +107,8 @@ void bad_trap(struct pt_regs *regs, long lvl)
 		regs->tpc &= 0xffffffff;
 		regs->tnpc &= 0xffffffff;
 	}
-	force_sig_fault(SIGILL, ILL_ILLTRP,
-			(void __user *)regs->tpc, lvl);
+	force_sig_fault_trapno(SIGILL, ILL_ILLTRP,
+			       (void __user *)regs->tpc, lvl);
 }
 
 void bad_trap_tl1(struct pt_regs *regs, long lvl)
@@ -201,8 +201,7 @@ void spitfire_insn_access_exception(struct pt_regs *regs, unsigned long sfsr, un
 		regs->tpc &= 0xffffffff;
 		regs->tnpc &= 0xffffffff;
 	}
-	force_sig_fault(SIGSEGV, SEGV_MAPERR,
-			(void __user *)regs->tpc, 0);
+	force_sig_fault(SIGSEGV, SEGV_MAPERR, (void __user *)regs->tpc);
 out:
 	exception_exit(prev_state);
 }
@@ -237,7 +236,7 @@ void sun4v_insn_access_exception(struct pt_regs *regs, unsigned long addr, unsig
 		regs->tpc &= 0xffffffff;
 		regs->tnpc &= 0xffffffff;
 	}
-	force_sig_fault(SIGSEGV, SEGV_MAPERR, (void __user *) addr, 0);
+	force_sig_fault(SIGSEGV, SEGV_MAPERR, (void __user *) addr);
 }
 
 void sun4v_insn_access_exception_tl1(struct pt_regs *regs, unsigned long addr, unsigned long type_ctx)
@@ -321,7 +320,7 @@ void spitfire_data_access_exception(struct pt_regs *regs, unsigned long sfsr, un
 	if (is_no_fault_exception(regs))
 		return;
 
-	force_sig_fault(SIGSEGV, SEGV_MAPERR, (void __user *)sfar, 0);
+	force_sig_fault(SIGSEGV, SEGV_MAPERR, (void __user *)sfar);
 out:
 	exception_exit(prev_state);
 }
@@ -385,13 +384,13 @@ void sun4v_data_access_exception(struct pt_regs *regs, unsigned long addr, unsig
 	 */
 	switch (type) {
 	case HV_FAULT_TYPE_INV_ASI:
-		force_sig_fault(SIGILL, ILL_ILLADR, (void __user *)addr, 0);
+		force_sig_fault(SIGILL, ILL_ILLADR, (void __user *)addr);
 		break;
 	case HV_FAULT_TYPE_MCD_DIS:
-		force_sig_fault(SIGSEGV, SEGV_ACCADI, (void __user *)addr, 0);
+		force_sig_fault(SIGSEGV, SEGV_ACCADI, (void __user *)addr);
 		break;
 	default:
-		force_sig_fault(SIGSEGV, SEGV_MAPERR, (void __user *)addr, 0);
+		force_sig_fault(SIGSEGV, SEGV_MAPERR, (void __user *)addr);
 		break;
 	}
 }
@@ -568,7 +567,7 @@ static void spitfire_ue_log(unsigned long afsr, unsigned long afar, unsigned lon
 		regs->tpc &= 0xffffffff;
 		regs->tnpc &= 0xffffffff;
 	}
-	force_sig_fault(SIGBUS, BUS_OBJERR, (void *)0, 0);
+	force_sig_fault(SIGBUS, BUS_OBJERR, (void *)0);
 }
 
 void spitfire_access_error(struct pt_regs *regs, unsigned long status_encoded, unsigned long afar)
@@ -2069,8 +2068,7 @@ void do_mcd_err(struct pt_regs *regs, struct sun4v_error_entry ent)
 	/* Send SIGSEGV to the userspace process with the right signal
 	 * code
 	 */
-	force_sig_fault(SIGSEGV, SEGV_ADIDERR, (void __user *)ent.err_raddr,
-			0);
+	force_sig_fault(SIGSEGV, SEGV_ADIDERR, (void __user *)ent.err_raddr);
 }
 
 /* We run with %pil set to PIL_NORMAL_MAX and PSTATE_IE enabled in %pstate.
@@ -2184,7 +2182,7 @@ bool sun4v_nonresum_error_user_handled(struct pt_regs *regs,
 	}
 	if (attrs & SUN4V_ERR_ATTRS_PIO) {
 		force_sig_fault(SIGBUS, BUS_ADRERR,
-				(void __user *)sun4v_get_vaddr(regs), 0);
+				(void __user *)sun4v_get_vaddr(regs));
 		return true;
 	}
 
@@ -2340,8 +2338,7 @@ static void do_fpe_common(struct pt_regs *regs)
 			else if (fsr & 0x01)
 				code = FPE_FLTRES;
 		}
-		force_sig_fault(SIGFPE, code,
-				(void __user *)regs->tpc, 0);
+		force_sig_fault(SIGFPE, code, (void __user *)regs->tpc);
 	}
 }
 
@@ -2395,8 +2392,7 @@ void do_tof(struct pt_regs *regs)
 		regs->tpc &= 0xffffffff;
 		regs->tnpc &= 0xffffffff;
 	}
-	force_sig_fault(SIGEMT, EMT_TAGOVF,
-			(void __user *)regs->tpc, 0);
+	force_sig_fault(SIGEMT, EMT_TAGOVF, (void __user *)regs->tpc);
 out:
 	exception_exit(prev_state);
 }
@@ -2415,8 +2411,7 @@ void do_div0(struct pt_regs *regs)
 		regs->tpc &= 0xffffffff;
 		regs->tnpc &= 0xffffffff;
 	}
-	force_sig_fault(SIGFPE, FPE_INTDIV,
-			(void __user *)regs->tpc, 0);
+	force_sig_fault(SIGFPE, FPE_INTDIV, (void __user *)regs->tpc);
 out:
 	exception_exit(prev_state);
 }
@@ -2612,7 +2607,7 @@ void do_illegal_instruction(struct pt_regs *regs)
 			}
 		}
 	}
-	force_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)pc, 0);
+	force_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)pc);
 out:
 	exception_exit(prev_state);
 }
@@ -2632,7 +2627,7 @@ void mem_address_unaligned(struct pt_regs *regs, unsigned long sfar, unsigned lo
 	if (is_no_fault_exception(regs))
 		return;
 
-	force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *)sfar, 0);
+	force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *)sfar);
 out:
 	exception_exit(prev_state);
 }
@@ -2650,7 +2645,7 @@ void sun4v_do_mna(struct pt_regs *regs, unsigned long addr, unsigned long type_c
 	if (is_no_fault_exception(regs))
 		return;
 
-	force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *) addr, 0);
+	force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *) addr);
 }
 
 /* sun4v_mem_corrupt_detect_precise() - Handle precise exception on an ADI
@@ -2697,7 +2692,7 @@ void sun4v_mem_corrupt_detect_precise(struct pt_regs *regs, unsigned long addr,
 		regs->tpc &= 0xffffffff;
 		regs->tnpc &= 0xffffffff;
 	}
-	force_sig_fault(SIGSEGV, SEGV_ADIPERR, (void __user *)addr, 0);
+	force_sig_fault(SIGSEGV, SEGV_ADIPERR, (void __user *)addr);
 }
 
 void do_privop(struct pt_regs *regs)
@@ -2712,8 +2707,7 @@ void do_privop(struct pt_regs *regs)
 		regs->tpc &= 0xffffffff;
 		regs->tnpc &= 0xffffffff;
 	}
-	force_sig_fault(SIGILL, ILL_PRVOPC,
-			(void __user *)regs->tpc, 0);
+	force_sig_fault(SIGILL, ILL_PRVOPC, (void __user *)regs->tpc);
 out:
 	exception_exit(prev_state);
 }
diff --git a/arch/sparc/kernel/unaligned_32.c b/arch/sparc/kernel/unaligned_32.c
index ef5c5207c9ff..455f0258c745 100644
--- a/arch/sparc/kernel/unaligned_32.c
+++ b/arch/sparc/kernel/unaligned_32.c
@@ -278,5 +278,5 @@ asmlinkage void user_unaligned_trap(struct pt_regs *regs, unsigned int insn)
 {
 	send_sig_fault(SIGBUS, BUS_ADRALN,
 		       (void __user *)safe_compute_effective_address(regs, insn),
-		       0, current);
+		       current);
 }
diff --git a/arch/sparc/mm/fault_32.c b/arch/sparc/mm/fault_32.c
index de2031c2b2d7..fa858626b85b 100644
--- a/arch/sparc/mm/fault_32.c
+++ b/arch/sparc/mm/fault_32.c
@@ -83,7 +83,7 @@ static void __do_fault_siginfo(int code, int sig, struct pt_regs *regs,
 		show_signal_msg(regs, sig, code,
 				addr, current);
 
-	force_sig_fault(sig, code, (void __user *) addr, 0);
+	force_sig_fault(sig, code, (void __user *) addr);
 }
 
 static unsigned long compute_si_addr(struct pt_regs *regs, int text_fault)
diff --git a/arch/sparc/mm/fault_64.c b/arch/sparc/mm/fault_64.c
index 0a6bcc85fba7..9a9652a15fed 100644
--- a/arch/sparc/mm/fault_64.c
+++ b/arch/sparc/mm/fault_64.c
@@ -176,7 +176,7 @@ static void do_fault_siginfo(int code, int sig, struct pt_regs *regs,
 	if (unlikely(show_unhandled_signals))
 		show_signal_msg(regs, sig, code, addr, current);
 
-	force_sig_fault(sig, code, (void __user *) addr, 0);
+	force_sig_fault(sig, code, (void __user *) addr);
 }
 
 static unsigned int get_fault_insn(struct pt_regs *regs, unsigned int insn)
diff --git a/arch/x86/kernel/signal_compat.c b/arch/x86/kernel/signal_compat.c
index 06743ec054d2..b52407c56000 100644
--- a/arch/x86/kernel/signal_compat.c
+++ b/arch/x86/kernel/signal_compat.c
@@ -34,7 +34,13 @@ static inline void signal_compat_build_tests(void)
 	BUILD_BUG_ON(NSIGSYS  != 2);
 
 	/* This is part of the ABI and can never change in size: */
+	BUILD_BUG_ON(sizeof(siginfo_t) != 128);
 	BUILD_BUG_ON(sizeof(compat_siginfo_t) != 128);
+
+	/* This is a part of the ABI and can never change in alignment */
+	BUILD_BUG_ON(__alignof__(siginfo_t) != 8);
+	BUILD_BUG_ON(__alignof__(compat_siginfo_t) != 4);
+
 	/*
 	 * The offsets of all the (unioned) si_fields are fixed
 	 * in the ABI, of course.  Make sure none of them ever