[PATCH] x86-64: Support -mregparm arguments for signals with SA_SIGINFO in compat mode

The recent change to make x86_64 support i386 binaries compiled
with -mregparm=3 only covered signal handlers without SA_SIGINFO.
(the 3-arg "real-time" ones)

To be compatible with i386, both types should be supported.
Signed-off-by: Albert Cahalan <acahalan@gmail.com>
Signed-off-by: Andi Kleen <ak@suse.de>

arch/x86_64/ia32/ia32_signal.c

@@ -584,6 +584,11 @@ int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 	regs->rdx = (unsigned long) &frame->info;
 	regs->rcx = (unsigned long) &frame->uc;
 
+	/* Make -mregparm=3 work */
+	regs->rax = sig;
+	regs->rdx = (unsigned long) &frame->info;
+	regs->rcx = (unsigned long) &frame->uc;
+
 	asm volatile("movl %0,%%ds" :: "r" (__USER32_DS)); 
 	asm volatile("movl %0,%%es" :: "r" (__USER32_DS));