Re: [Qemu-devel] [PATCH] cpu-exec(): also reload CPUClass *cc after longjmp return

[Peter Maydell]

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...

-- PMM