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 <[EMAIL PROTECTED]>



---
 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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