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>

1 files changed, 10 insertions, 0 deletions

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;