[ARM] Add identifying number for non-rt sigframe

GDB couldn't reliably tell the difference between the old and new
non-rt sigframes, so provide it with a number at the beginning which
will never appear in the old sigframe, and hence provide gdb with a
reliable way to tell the two apart.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index 9628511440996ab7080b8f8dceff223946bc7336..c0ba8afee42fd4b3c984c02a3b0b68d36716ca79 100644 (file)
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -470,6 +470,11 @@ setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *reg
        if (!frame)
                return 1;
 
+       /*
+        * Set uc.uc_flags to a value which sc.trap_no would never have.
+        */
+       __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);
+
        err |= setup_sigframe(frame, regs, set);
        if (err == 0)
                err = setup_return(regs, ka, frame->retcode, frame, usig);