Re: [Qemu-devel] [PATCH 3/4] linux-user: ARM: clear the IT bits when invoking a signal handler

[Aurelien Jarno <aurelien@aurel32.net>]

On Mon, Jan 10, 2011 at 11:11:51PM +0000, Peter Maydell wrote:
> When invoking a signal handler for an ARM target, make sure the IT
> bits in the CPSR are cleared. (This would otherwise cause incorrect
> execution if the IT state was non-zero when an exception occured.
> This bug has been masked previously because we weren't getting the
> IT state bits at exception entry right anyway.)
> 
> Also use the proper cpsr_read()/cpsr_write() interface to update
> the CPSR rather than manipulating CPUState fields directly.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  linux-user/signal.c |   16 +++++++++-------
>  1 files changed, 9 insertions(+), 7 deletions(-)

Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>

> diff --git a/linux-user/signal.c b/linux-user/signal.c
> index c846b8c..0664770 100644
> --- a/linux-user/signal.c
> +++ b/linux-user/signal.c
> @@ -1256,6 +1256,14 @@ setup_return(CPUState *env, struct target_sigaction *ka,
>  	abi_ulong handler = ka->_sa_handler;
>  	abi_ulong retcode;
>  	int thumb = handler & 1;
> +	uint32_t cpsr = cpsr_read(env);
> +
> +	cpsr &= ~CPSR_IT;
> +	if (thumb) {
> +		cpsr |= CPSR_T;
> +	} else {
> +		cpsr &= ~CPSR_T;
> +	}
>  
>  	if (ka->sa_flags & TARGET_SA_RESTORER) {
>  		retcode = ka->sa_restorer;
> @@ -1278,13 +1286,7 @@ setup_return(CPUState *env, struct target_sigaction *ka,
>  	env->regs[13] = frame_addr;
>  	env->regs[14] = retcode;
>  	env->regs[15] = handler & (thumb ? ~1 : ~3);
> -	env->thumb = thumb;
> -
> -#if 0
> -#ifdef TARGET_CONFIG_CPU_32
> -	env->cpsr = cpsr;
> -#endif
> -#endif
> +	cpsr_write(env, cpsr, 0xffffffff);
>  
>  	return 0;
>  }
> -- 
> 1.7.1
> 
> 
> 

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net