* Eric W. Biederman [off-list ref]:

Setting si_code to __SI_FAULT results in a userspace seeing
an si_code of 0.  This is the same si_code as SI_USER.  Posix
and common sense requires that SI_USER not be a signal specific
si_code.  As such this use of 0 for the si_code is a pretty
horribly broken ABI.

Given that alpha is on it's last legs I don't know that it is worth
fixing this, but it is worth documenting what is going on so that
no one decides to copy this bad decision.

The ABI was already broken, so IMHO I think it's better to somehow "fix"
it instead. Agreed, alpha and some other architectures are already aged,
but nevertheless most of them build in debian-ports.  Below is a
suggested fix which reuses/misuses other existing trap codes instead.

Helge

Signed-off-by: Helge Deller <deller@gmx.de>

diff --git a/arch/alpha/kernel/traps.c b/arch/alpha/kernel/traps.c
index 65bb102..2ed37dd 100644
--- a/arch/alpha/kernel/traps.c
+++ b/arch/alpha/kernel/traps.c

@@ -278,7 +278,7 @@ do_entIF(unsigned long type, struct pt_regs *regs)
 	      case 1: /* bugcheck */
 		info.si_signo = SIGTRAP;
 		info.si_errno = 0;
-		info.si_code = __SI_FAULT;
+		info.si_code = TRAP_HWBKPT;
 		info.si_addr = (void __user *) regs->pc;
 		info.si_trapno = 0;
 		send_sig_info(SIGTRAP, &info, current);

@@ -318,7 +318,7 @@ do_entIF(unsigned long type, struct pt_regs *regs)
 			break;
 		case GEN_ROPRAND:
 			signo = SIGFPE;
-			code = __SI_FAULT;
+			code = FPE_FLTSUB;
 			break;
 
 		case GEN_DECOVF:

@@ -340,7 +340,7 @@ do_entIF(unsigned long type, struct pt_regs *regs)
 		case GEN_SUBRNG7:
 		default:
 			signo = SIGTRAP;
-			code = __SI_FAULT;
+			code = TRAP_HWBKPT;
 			break;
 		}