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Re: [Qemu-devel] [PATCH] cpu-exec(): also reload CPUClass *cc after long
From: |
Jan Kiszka |
Subject: |
Re: [Qemu-devel] [PATCH] cpu-exec(): also reload CPUClass *cc after longjmp return |
Date: |
Fri, 04 Oct 2013 09:15:37 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
On 2013-10-03 18:05, Peter Maydell wrote:
> On 3 October 2013 23:09, Juergen Lock <address@hidden> wrote:
>> Local variable CPUClass *cc needs to be reloaded after return from longjmp
>> too. (This fixes the mips-softmmu crash observed on FreeBSD when qemu is
>> built with clang.)
>>
>> Signed-off-by: Juergen Lock <address@hidden>
>> Found-by: Dimitry Andric <address@hidden>
>>
>> --- a/cpu-exec.c
>> +++ b/cpu-exec.c
>> @@ -681,6 +681,10 @@ int cpu_exec(CPUArchState *env)
>> * local variables as longjmp is marked 'noreturn'. */
>> cpu = current_cpu;
>> env = cpu->env_ptr;
>> +#if !(defined(CONFIG_USER_ONLY) && \
>> + (defined(TARGET_M68K) || defined(TARGET_PPC) ||
>> defined(TARGET_S390X)))
>> + cc = CPU_GET_CLASS(cpu);
>> +#endif
>
> This is a c compiler or libc bug -- the C standard says that this
> local variable should not be trashed by the longjmp. We were
> actually discussing removing the current workarounds there...
But we didn't decide if we should stop supporting the affected compiler
versions.
Does this issue also exist with the latest clang version available for
your platform?
Jan
--
Siemens AG, Corporate Technology, CT RTC ITP SES-DE
Corporate Competence Center Embedded Linux