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Re: issue with SIGPROF signal handler on ARM
- From: Daniel Jacobowitz <drow at false dot org>
- To: Arvind Ayyangar <arvind dot ayyangar at gmail dot com>
- Cc: libc-ports at sourceware dot org, Russell King - ARM Linux <linux at arm dot linux dot org dot uk>, Jan Rinze <janrinze at home dot nl>
- Date: Fri, 21 Dec 2007 12:01:44 -0500
- Subject: Re: issue with SIGPROF signal handler on ARM
- References: <c34bb56f0710100535i6db080b3vf0222c95a815879f@mail.gmail.com>
On Wed, Oct 10, 2007 at 06:05:53PM +0530, Arvind Ayyangar wrote:
> I changed the prototype of profil_counter from
> profil_counter (int signo, int _a2, int _a3, int _a4, union
> k_sigcontext sc) to
> profil_counter (int signo, siginfo_t *sig_info, struct sigcontext
> *scp) and passed the pc value stored in ((struct ucontext *)
> scp)->uc_mcontext.arm_pc. Here, the PC value passed to the signal
> handler seems to be as expected.
I assume you also had to change the signal handler to set SA_SIGINFO;
if you didn't I'm not sure why it worked. Here's what I checked
in to fix this.
--
Daniel Jacobowitz
CodeSourcery
2007-12-21 Daniel Jacobowitz <dan@codesourcery.com>
* sysdeps/unix/sysv/linux/arm/profil-counter.h: Use the i386 version.
* sysdeps/unix/sysv/linux/arm/register-dump.h (register_dump): Update
to use ucontext.
(REGISTER_DUMP): Likewise.
* sysdeps/unix/sysv/linux/arm/sigcontextinfo.h (SIGCONTEXT,
SIGCONTEXT_EXTRA_ARGS, GET_PC, GET_FRAME, GET_STACK): Likewise.
(sigaction, __sigaction): Define.
* sysdeps/unix/sysv/linux/arm/bits/armsigctx.h: Delete.
Index: sysdeps/unix/sysv/linux/arm/profil-counter.h
===================================================================
RCS file: /cvs/glibc/ports/sysdeps/unix/sysv/linux/arm/profil-counter.h,v
retrieving revision 1.8
diff -u -p -r1.8 profil-counter.h
--- sysdeps/unix/sysv/linux/arm/profil-counter.h 14 Oct 2002 17:26:14 -0000 1.8
+++ sysdeps/unix/sysv/linux/arm/profil-counter.h 21 Dec 2007 16:29:19 -0000
@@ -1,37 +1,2 @@
-/* Low-level statistical profiling support function. Linux/ARM version.
- Copyright (C) 1996, 1997, 1998, 2002 Free Software Foundation, Inc.
- This file is part of the GNU C Library.
-
- The GNU C Library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public
- License as published by the Free Software Foundation; either
- version 2.1 of the License, or (at your option) any later version.
-
- The GNU C Library is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public
- License along with the GNU C Library; if not, write to the Free
- Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
- 02111-1307 USA. */
-
-#include <signal.h>
-#include <bits/armsigctx.h>
-
-void
-profil_counter (int signo, int _a2, int _a3, int _a4, union k_sigcontext sc)
-{
- void *pc;
- if (sc.v20.magic == SIGCONTEXT_2_0_MAGIC)
- pc = (void *) sc.v20.reg.ARM_pc;
- else
- pc = (void *) sc.v21.arm_pc;
- profil_count (pc);
-
- /* This is a hack to prevent the compiler from implementing the
- above function call as a sibcall. The sibcall would overwrite
- the signal context. */
- asm volatile ("");
-}
+/* We can use the ix86 version. */
+#include <sysdeps/unix/sysv/linux/i386/profil-counter.h>
Index: sysdeps/unix/sysv/linux/arm/register-dump.h
===================================================================
RCS file: /cvs/glibc/ports/sysdeps/unix/sysv/linux/arm/register-dump.h,v
retrieving revision 1.5
diff -u -p -r1.5 register-dump.h
--- sysdeps/unix/sysv/linux/arm/register-dump.h 6 Jul 2001 04:56:13 -0000 1.5
+++ sysdeps/unix/sysv/linux/arm/register-dump.h 21 Dec 2007 16:29:19 -0000
@@ -20,7 +20,7 @@
#include <sys/uio.h>
#include <stdio-common/_itoa.h>
-#include <bits/armsigctx.h>
+#include <sys/ucontext.h>
/* We will print the register dump in this format:
@@ -45,7 +45,7 @@ hexvalue (unsigned long int value, char
}
static void
-register_dump (int fd, union k_sigcontext *ctx)
+register_dump (int fd, const struct ucontext *ctx)
{
char regs[21][8];
struct iovec iov[97];
@@ -61,53 +61,27 @@ register_dump (int fd, union k_sigcontex
++nr
/* Generate strings of register contents. */
- if (ctx->v20.magic == SIGCONTEXT_2_0_MAGIC)
- {
- hexvalue (ctx->v20.reg.ARM_r0, regs[0], 8);
- hexvalue (ctx->v20.reg.ARM_r1, regs[1], 8);
- hexvalue (ctx->v20.reg.ARM_r2, regs[2], 8);
- hexvalue (ctx->v20.reg.ARM_r3, regs[3], 8);
- hexvalue (ctx->v20.reg.ARM_r4, regs[4], 8);
- hexvalue (ctx->v20.reg.ARM_r5, regs[5], 8);
- hexvalue (ctx->v20.reg.ARM_r6, regs[6], 8);
- hexvalue (ctx->v20.reg.ARM_r7, regs[7], 8);
- hexvalue (ctx->v20.reg.ARM_r8, regs[8], 8);
- hexvalue (ctx->v20.reg.ARM_r9, regs[9], 8);
- hexvalue (ctx->v20.reg.ARM_r10, regs[10], 8);
- hexvalue (ctx->v20.reg.ARM_fp, regs[11], 8);
- hexvalue (ctx->v20.reg.ARM_ip, regs[12], 8);
- hexvalue (ctx->v20.reg.ARM_sp, regs[13], 8);
- hexvalue (ctx->v20.reg.ARM_lr, regs[14], 8);
- hexvalue (ctx->v20.reg.ARM_pc, regs[15], 8);
- hexvalue (ctx->v20.reg.ARM_cpsr, regs[16], 8);
- hexvalue (ctx->v20.trap_no, regs[17], 8);
- hexvalue (ctx->v20.error_code, regs[18], 8);
- hexvalue (ctx->v20.oldmask, regs[19], 8);
- }
- else
- {
- hexvalue (ctx->v21.arm_r0, regs[0], 8);
- hexvalue (ctx->v21.arm_r1, regs[1], 8);
- hexvalue (ctx->v21.arm_r2, regs[2], 8);
- hexvalue (ctx->v21.arm_r3, regs[3], 8);
- hexvalue (ctx->v21.arm_r4, regs[4], 8);
- hexvalue (ctx->v21.arm_r5, regs[5], 8);
- hexvalue (ctx->v21.arm_r6, regs[6], 8);
- hexvalue (ctx->v21.arm_r7, regs[7], 8);
- hexvalue (ctx->v21.arm_r8, regs[8], 8);
- hexvalue (ctx->v21.arm_r9, regs[9], 8);
- hexvalue (ctx->v21.arm_r10, regs[10], 8);
- hexvalue (ctx->v21.arm_fp, regs[11], 8);
- hexvalue (ctx->v21.arm_ip, regs[12], 8);
- hexvalue (ctx->v21.arm_sp, regs[13], 8);
- hexvalue (ctx->v21.arm_lr, regs[14], 8);
- hexvalue (ctx->v21.arm_pc, regs[15], 8);
- hexvalue (ctx->v21.arm_cpsr, regs[16], 8);
- hexvalue (ctx->v21.trap_no, regs[17], 8);
- hexvalue (ctx->v21.error_code, regs[18], 8);
- hexvalue (ctx->v21.oldmask, regs[19], 8);
- hexvalue (ctx->v21.fault_address, regs[20], 8);
- }
+ hexvalue (ctx->uc_mcontext.arm_r0, regs[0], 8);
+ hexvalue (ctx->uc_mcontext.arm_r1, regs[1], 8);
+ hexvalue (ctx->uc_mcontext.arm_r2, regs[2], 8);
+ hexvalue (ctx->uc_mcontext.arm_r3, regs[3], 8);
+ hexvalue (ctx->uc_mcontext.arm_r4, regs[4], 8);
+ hexvalue (ctx->uc_mcontext.arm_r5, regs[5], 8);
+ hexvalue (ctx->uc_mcontext.arm_r6, regs[6], 8);
+ hexvalue (ctx->uc_mcontext.arm_r7, regs[7], 8);
+ hexvalue (ctx->uc_mcontext.arm_r8, regs[8], 8);
+ hexvalue (ctx->uc_mcontext.arm_r9, regs[9], 8);
+ hexvalue (ctx->uc_mcontext.arm_r10, regs[10], 8);
+ hexvalue (ctx->uc_mcontext.arm_fp, regs[11], 8);
+ hexvalue (ctx->uc_mcontext.arm_ip, regs[12], 8);
+ hexvalue (ctx->uc_mcontext.arm_sp, regs[13], 8);
+ hexvalue (ctx->uc_mcontext.arm_lr, regs[14], 8);
+ hexvalue (ctx->uc_mcontext.arm_pc, regs[15], 8);
+ hexvalue (ctx->uc_mcontext.arm_cpsr, regs[16], 8);
+ hexvalue (ctx->uc_mcontext.trap_no, regs[17], 8);
+ hexvalue (ctx->uc_mcontext.error_code, regs[18], 8);
+ hexvalue (ctx->uc_mcontext.oldmask, regs[19], 8);
+ hexvalue (ctx->uc_mcontext.fault_address, regs[20], 8);
/* Generate the output. */
ADD_STRING ("Register dump:\n\n R0: ");
@@ -150,11 +124,8 @@ register_dump (int fd, union k_sigcontex
ADD_MEM (regs[18], 8);
ADD_STRING (" OldMask: ");
ADD_MEM (regs[19], 8);
- if (ctx->v20.magic != SIGCONTEXT_2_0_MAGIC)
- {
- ADD_STRING ("\n Addr: ");
- ADD_MEM (regs[20], 8);
- }
+ ADD_STRING ("\n Addr: ");
+ ADD_MEM (regs[20], 8);
ADD_STRING ("\n");
@@ -163,4 +134,4 @@ register_dump (int fd, union k_sigcontex
}
-#define REGISTER_DUMP register_dump (fd, &ctx)
+#define REGISTER_DUMP register_dump (fd, ctx)
Index: sysdeps/unix/sysv/linux/arm/sigcontextinfo.h
===================================================================
RCS file: /cvs/glibc/ports/sysdeps/unix/sysv/linux/arm/sigcontextinfo.h,v
retrieving revision 1.8
diff -u -p -r1.8 sigcontextinfo.h
--- sysdeps/unix/sysv/linux/arm/sigcontextinfo.h 21 Dec 2002 18:37:16 -0000 1.8
+++ sysdeps/unix/sysv/linux/arm/sigcontextinfo.h 21 Dec 2007 16:29:19 -0000
@@ -17,35 +17,34 @@
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
-#include <bits/armsigctx.h>
+#include <sys/ucontext.h>
#include "kernel-features.h"
-#define SIGCONTEXT int _a2, int _a3, int _a4, union k_sigcontext
-#define SIGCONTEXT_EXTRA_ARGS _a2, _a3, _a4,
+#define SIGCONTEXT siginfo_t *_si, struct ucontext *
+#define SIGCONTEXT_EXTRA_ARGS _si,
/* The sigcontext structure changed between 2.0 and 2.1 kernels. On any
modern system we should be able to assume that the "new" format will be
in use. */
-#if __LINUX_KERNEL_VERSION > 131328
-#define GET_PC(ctx) ((void *) ctx.v21.arm_pc)
-#define GET_FRAME(ctx) ADVANCE_STACK_FRAME ((void *) ctx.v21.arm_fp)
-#define GET_STACK(ctx) ((void *) ctx.v21.arm_sp)
-
-#else
-
-#define GET_PC(ctx) ((void *)((ctx.v20.magic == SIGCONTEXT_2_0_MAGIC) ? \
- ctx.v20.reg.ARM_pc : ctx.v21.arm_pc))
-#define GET_FRAME(ctx) \
- ADVANCE_STACK_FRAME((void *)((ctx.v20.magic == SIGCONTEXT_2_0_MAGIC) ? \
- ctx.v20.reg.ARM_fp : ctx.v21.arm_fp))
-#define GET_STACK(ctx) ((void *)((ctx.v20.magic == SIGCONTEXT_2_0_MAGIC) ? \
- ctx.v20.reg.ARM_sp : ctx.v21.arm_sp))
-
-#endif
+#define GET_PC(ctx) ((void *) (ctx)->uc_mcontext.arm_pc)
+#define GET_FRAME(ctx) ADVANCE_STACK_FRAME ((void *) ctx->uc_mcontext.arm_fp)
+#define GET_STACK(ctx) ((void *) (ctx)->uc_mcontext.arm_sp)
#define ADVANCE_STACK_FRAME(frm) \
((struct layout *)frm - 1)
#define CALL_SIGHANDLER(handler, signo, ctx) \
(handler)((signo), SIGCONTEXT_EXTRA_ARGS (ctx))
+
+/* There is no reliable way to get the sigcontext unless we use a
+ three-argument signal handler. */
+#define __sigaction(sig, act, oact) ({ \
+ (act)->sa_flags |= SA_SIGINFO; \
+ (__sigaction) (sig, act, oact); \
+})
+
+#define sigaction(sig, act, oact) ({ \
+ (act)->sa_flags |= SA_SIGINFO; \
+ (sigaction) (sig, act, oact); \
+})
Index: sysdeps/unix/sysv/linux/arm/bits/armsigctx.h
===================================================================
RCS file: sysdeps/unix/sysv/linux/arm/bits/armsigctx.h
diff -N sysdeps/unix/sysv/linux/arm/bits/armsigctx.h
--- sysdeps/unix/sysv/linux/arm/bits/armsigctx.h 6 Jul 2001 04:56:13 -0000 1.5
+++ /dev/null 1 Jan 1970 00:00:00 -0000
@@ -1,73 +0,0 @@
-/* Definition of `struct sigcontext' for Linux/ARM
- Copyright (C) 1996, 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
- This file is part of the GNU C Library.
-
- The GNU C Library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public
- License as published by the Free Software Foundation; either
- version 2.1 of the License, or (at your option) any later version.
-
- The GNU C Library is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public
- License along with the GNU C Library; if not, write to the Free
- Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
- 02111-1307 USA. */
-
-/* The format of struct sigcontext changed between 2.0 and 2.1 kernels.
- Fortunately 2.0 puts a magic number in the first word and this is not
- a legal value for `trap_no', so we can tell them apart. */
-
-/* Early 2.2 and 2.3 kernels do not have the `fault_address' member in
- the sigcontext structure. Unfortunately there is no reliable way
- to test for its presence and this word will contain garbage for too-old
- kernels. Versions 2.2.14 and 2.3.35 (plus later versions) are known to
- include this element. */
-
-#ifndef __ARMSIGCTX_H
-#define __ARMSIGCTX_H 1
-
-#include <asm/ptrace.h>
-
-union k_sigcontext
- {
- struct
- {
- unsigned long int trap_no;
- unsigned long int error_code;
- unsigned long int oldmask;
- unsigned long int arm_r0;
- unsigned long int arm_r1;
- unsigned long int arm_r2;
- unsigned long int arm_r3;
- unsigned long int arm_r4;
- unsigned long int arm_r5;
- unsigned long int arm_r6;
- unsigned long int arm_r7;
- unsigned long int arm_r8;
- unsigned long int arm_r9;
- unsigned long int arm_r10;
- unsigned long int arm_fp;
- unsigned long int arm_ip;
- unsigned long int arm_sp;
- unsigned long int arm_lr;
- unsigned long int arm_pc;
- unsigned long int arm_cpsr;
- unsigned long fault_address;
- } v21;
- struct
- {
- unsigned long int magic;
- struct pt_regs reg;
- unsigned long int trap_no;
- unsigned long int error_code;
- unsigned long int oldmask;
- } v20;
-};
-
-#define SIGCONTEXT_2_0_MAGIC 0x4B534154
-
-#endif /* bits/armsigctx.h */