signals: demultiplexing SIGTRAP signal

Currently a SIGTRAP can denote any one of below reasons.
	- Breakpoint hit
	- H/W debug register hit
	- Single step
	- 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@in.ibm.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: akpm@linux-foundation.org
Cc: paulus@samba.org
Cc: linuxppc-dev@ozlabs.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>

4 files changed, 13 insertions, 6 deletions

diff --git a/include/asm-generic/siginfo.h b/include/asm-generic/siginfo.h
index 8786e01e0db8..969570167e9e 100644
--- a/include/asm-generic/siginfo.h
+++ b/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/watchpoint */
 #define NSIGTRAP        2
 
 /*
diff --git a/include/asm-parisc/siginfo.h b/include/asm-parisc/siginfo.h
index d4909f55fe35..d7034728f377 100644
--- a/include/asm-parisc/siginfo.h
+++ b/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
 
diff --git a/include/asm-x86/ptrace.h b/include/asm-x86/ptrace.h
index fad807769910..c2f368273079 100644
--- a/include/asm-x86/ptrace.h
+++ b/include/asm-x86/ptrace.h
@@ -143,7 +143,7 @@ convert_ip_to_linear(struct task_struct *child, struct pt_regs *regs);
 
 #ifdef CONFIG_X86_32
 extern void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
-                         int error_code);
+                         int error_code, int si_code);
 #endif
 
 void signal_fault(struct pt_regs *regs, void __user *frame, char *where);
diff --git a/include/asm-x86/traps.h b/include/asm-x86/traps.h
index 2ccebc6fb0b0..4b1e90409251 100644
--- a/include/asm-x86/traps.h
+++ b/include/asm-x86/traps.h
@@ -36,6 +36,16 @@ void do_invalid_op(struct pt_regs *, long);
 void do_general_protection(struct pt_regs *, long);
 void do_nmi(struct pt_regs *, long);
 
+static inline int get_si_code(unsigned long condition)
+{
+        if (condition & DR_STEP)
+                return TRAP_TRACE;
+        else if (condition & (DR_TRAP0|DR_TRAP1|DR_TRAP2|DR_TRAP3))
+                return TRAP_HWBKPT;
+        else
+                return TRAP_BRKPT;
+}
+
 extern int panic_on_unrecovered_nmi;
 extern int kstack_depth_to_print;