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[PATCH][AArch32][libgloss] Fix semihosting SYS_EXIT call on semihosting v1.
- From: Tamar Christina <Tamar dot Christina at arm dot com>
- To: "newlib at sourceware dot org" <newlib at sourceware dot org>
- Cc: nd <nd at arm dot com>
- Date: Wed, 11 Jul 2018 12:39:18 +0000
- Subject: [PATCH][AArch32][libgloss] Fix semihosting SYS_EXIT call on semihosting v1.
Hi All,
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
Cross compiled arm-none-eabi and regtested using check-gcc and no regressions.
Ok for master?
PS. I do not have commit rights so if OK can someone apply for me?
Thanks,
Tamar
From 5c8c95cdf19602fb3ad569fbcbeda4ce5304b537 Mon Sep 17 00:00:00 2001
From: Tamar Christina <tamar.christina@arm.com>
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 <tamar.christina@arm.com>
---
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
--
2.17.1