x86, trace: Register exception handler to trace IDT

This patch registers exception handlers for tracing to a trace IDT.

To implemented it in set_intr_gate(), this patch does followings.
 - Register the exception handlers to
   the trace IDT by prepending "trace_" to the handler's names.
 - Also, newly introduce trace_page_fault() to add tracepoints
   in a subsequent patch.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Link: http://lkml.kernel.org/r/52716DEC.5050204@hds.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 3aaeffcfd67a..fd3e281fbc70 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1231,3 +1231,13 @@ do_page_fault(struct pt_regs *regs, unsigned long error_code)
         __do_page_fault(regs, error_code);
         exception_exit(prev_state);
 }
+
+dotraplinkage void __kprobes
+trace_do_page_fault(struct pt_regs *regs, unsigned long error_code)
+{
+        enum ctx_state prev_state;
+
+        prev_state = exception_enter();
+        __do_page_fault(regs, error_code);
+        exception_exit(prev_state);
+}