[PATCH][AArch32][libgloss] Fix semihosting SYS_EXIT call on semihosting v1.

[Corinna Vinschen]

On Jul 11 12:39, Tamar Christina wrote:
> 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(+)

Pushed.


Thanks,
Corinna

-- 
Corinna Vinschen
Cygwin Maintainer
Red Hat
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