[PATCH v2] mips: fix abort on integer overflow

[Mikulas Patocka]

On Thu, 28 Sep 2023, Richard Henderson wrote:

> Just call force_sig_fault directly.
> 
> 
> r~

OK. Here I'm resending it.

Mikulas



From: Mikulas Patocka <mpatocka@redhat.com>

Qemu mips userspace emulation crashes with "qemu: unhandled CPU exception 
0x15 - aborting" when one of the integer arithmetic instructions detects 
an overflow.

This patch fixes it so that it delivers SIGFPE with FPE_INTOVF instead.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: qemu-stable@nongnu.org

---
 linux-user/mips/cpu_loop.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Index: qemu/linux-user/mips/cpu_loop.c
===================================================================
--- qemu.orig/linux-user/mips/cpu_loop.c
+++ qemu/linux-user/mips/cpu_loop.c
@@ -180,7 +180,9 @@ done_syscall:
             }
             force_sig_fault(TARGET_SIGFPE, si_code, env->active_tc.PC);
             break;
-
+       case EXCP_OVERFLOW:
+            force_sig_fault(TARGET_SIGFPE, TARGET_FPE_INTOVF, 
env->active_tc.PC);
+            break;
         /* The code below was inspired by the MIPS Linux kernel trap
          * handling code in arch/mips/kernel/traps.c.
          */