[RFC][PATCH] Demultiplexing SIGTRAP signal
From: Srinivasa Ds
Date: Mon Sep 22 2008 - 06:32:23 EST
Currently a SIGTRAP signal can denote any one of below reasons.
- Breakpoint hit
- H/W debug register hit
- Single step
- SIGTRAP signal sent through kill() or rasie()
Architectures like powerpc/parisc provides infrastructure to demultiplex
SIGTRAP signal by passing down the information for receiving SIGTRAP through
si_code of siginfot_t structure. Here is an attempt is generalise this
infrastructure by extending it to x86 and x86_64 archs.
Signed-off-by: Srinivasa DS <srinivasa@xxxxxxxxxx>
---
arch/ia64/include/asm/siginfo.h | 5 -----
arch/powerpc/include/asm/siginfo.h | 5 -----
arch/x86/kernel/traps_32.c | 19 +++++++++++++++++--
arch/x86/kernel/traps_64.c | 7 ++++++-
include/asm-generic/siginfo.h | 2 ++
include/asm-parisc/siginfo.h | 5 -----
6 files changed, 25 insertions(+), 18 deletions(-)
Index: linux-2.6.27-rc7/arch/ia64/include/asm/siginfo.h
===================================================================
--- linux-2.6.27-rc7.orig/arch/ia64/include/asm/siginfo.h
+++ linux-2.6.27-rc7/arch/ia64/include/asm/siginfo.h
@@ -113,11 +113,6 @@ typedef struct siginfo {
#undef NSIGSEGV
#define NSIGSEGV 3
-/*
- * SIGTRAP si_codes
- */
-#define TRAP_BRANCH (__SI_FAULT|3) /* process taken branch trap */
-#define TRAP_HWBKPT (__SI_FAULT|4) /* hardware breakpoint or watchpoint */
#undef NSIGTRAP
#define NSIGTRAP 4
Index: linux-2.6.27-rc7/arch/powerpc/include/asm/siginfo.h
===================================================================
--- linux-2.6.27-rc7.orig/arch/powerpc/include/asm/siginfo.h
+++ linux-2.6.27-rc7/arch/powerpc/include/asm/siginfo.h
@@ -15,11 +15,6 @@
#include <asm-generic/siginfo.h>
-/*
- * SIGTRAP si_codes
- */
-#define TRAP_BRANCH (__SI_FAULT|3) /* process taken branch trap */
-#define TRAP_HWBKPT (__SI_FAULT|4) /* hardware breakpoint or watchpoint */
#undef NSIGTRAP
#define NSIGTRAP 4
Index: linux-2.6.27-rc7/arch/x86/kernel/traps_32.c
===================================================================
--- linux-2.6.27-rc7.orig/arch/x86/kernel/traps_32.c
+++ linux-2.6.27-rc7/arch/x86/kernel/traps_32.c
@@ -890,6 +890,7 @@ void __kprobes do_int3(struct pt_regs *r
void __kprobes do_debug(struct pt_regs *regs, long error_code)
{
struct task_struct *tsk = current;
+ struct siginfo info;
unsigned int condition;
trace_hardirqs_fixup();
@@ -935,8 +936,22 @@ void __kprobes do_debug(struct pt_regs *
goto clear_TF_reenable;
}
- /* Ok, finally something we can handle */
- send_sigtrap(tsk, regs, error_code);
+ tsk->thread.trap_no = 1;
+ tsk->thread.error_code = error_code;
+
+ memset(&info, 0, sizeof(info));
+ info.si_signo = SIGTRAP;
+ if (condition & DR_STEP)
+ info.si_code = TRAP_TRACE;
+ else if (condition & (DR_TRAP0|DR_TRAP1|DR_TRAP2|DR_TRAP3))
+ info.si_code = TRAP_HWBKPT;
+ else
+ info.si_code = TRAP_BRKPT;
+ /* User-mode ip? */
+ info.si_addr = user_mode_vm(regs) ? (void __user *) regs->ip : NULL;
+
+ /* Send us the fake SIGTRAP */
+ force_sig_info(SIGTRAP, &info, tsk);
/*
* Disable additional traps. They'll be re-enabled when
Index: linux-2.6.27-rc7/arch/x86/kernel/traps_64.c
===================================================================
--- linux-2.6.27-rc7.orig/arch/x86/kernel/traps_64.c
+++ linux-2.6.27-rc7/arch/x86/kernel/traps_64.c
@@ -936,7 +936,12 @@ asmlinkage void __kprobes do_debug(struc
tsk->thread.error_code = error_code;
info.si_signo = SIGTRAP;
info.si_errno = 0;
- info.si_code = TRAP_BRKPT;
+ if (condition & DR_STEP)
+ info.si_code = TRAP_TRACE;
+ else if (condition & (DR_TRAP0|DR_TRAP1|DR_TRAP2|DR_TRAP3))
+ info.si_code = TRAP_HWBKPT;
+ else
+ info.si_code = TRAP_BRKPT;
info.si_addr = user_mode(regs) ? (void __user *)regs->ip : NULL;
force_sig_info(SIGTRAP, &info, tsk);
Index: linux-2.6.27-rc7/include/asm-generic/siginfo.h
===================================================================
--- linux-2.6.27-rc7.orig/include/asm-generic/siginfo.h
+++ linux-2.6.27-rc7/include/asm-generic/siginfo.h
@@ -199,6 +199,8 @@ typedef struct siginfo {
*/
#define TRAP_BRKPT (__SI_FAULT|1) /* process breakpoint */
#define TRAP_TRACE (__SI_FAULT|2) /* process trace trap */
+#define TRAP_BRANCH (__SI_FAULT|3) /* process taken branch trap */
+#define TRAP_HWBKPT (__SI_FAULT|4) /* hardware breakpoint or watchpoint
*/
#define NSIGTRAP 2
/*
Index: linux-2.6.27-rc7/include/asm-parisc/siginfo.h
===================================================================
--- linux-2.6.27-rc7.orig/include/asm-parisc/siginfo.h
+++ linux-2.6.27-rc7/include/asm-parisc/siginfo.h
@@ -3,11 +3,6 @@
#include <asm-generic/siginfo.h>
-/*
- * SIGTRAP si_codes
- */
-#define TRAP_BRANCH (__SI_FAULT|3) /* process taken branch trap */
-#define TRAP_HWBKPT (__SI_FAULT|4) /* hardware breakpoint or watchpoint */
#undef NSIGTRAP
#define NSIGTRAP 4
--
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