From 430b52911102a2ee48f1857954f2aeacc5b56dc6 Mon Sep 17 00:00:00 2001 From: Tamar Christina Date: Wed, 11 Jul 2018 13:26:16 +0100 Subject: [PATCH] Fix AArch32 semihosting SYS_EXIT call on semihosting v1. The current SYS_EXIT has a bug that when making the call it always uses the v2 calling convention. This is undefined behavior according to the semihosting specification: https://developer.arm.com/docs/100863/latest/semihosting-operations/sys_exit-0x18 This patch fixes it by making sure v1 passes the argument directly in the register instead of in a block. And for v2 it does the same if the v2 extension isn't supported. The sequence generated now is 12424: ebfffecd bl 11f60 <_has_ext_exit_extended> 12428: e3500000 cmp r0, #0 1242c: 11a0500d movne r5, sp 12430: 059d5000 ldreq r5, [sp] 12434: e1a00004 mov r0, r4 12438: e1a01005 mov r1, r5 1243c: ef00f000 svc 0x0000f000 Signed-off-by: Tamar Christina --- libgloss/arm/_kill.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/libgloss/arm/_kill.c b/libgloss/arm/_kill.c index fc77e8097..278ded73a 100644 --- a/libgloss/arm/_kill.c +++ b/libgloss/arm/_kill.c @@ -39,7 +39,13 @@ _kill (int pid, int sig) } } +#if SEMIHOST_V2 +if (_has_ext_exit_extended ()) return do_AngelSWI (insn, block); +else +#endif + return do_AngelSWI (insn, (void*)block[0]); + #else asm ("swi %a0" :: "i" (SWI_Exit)); #endif