Patchwork [3/4] linux-user: ARM: clear the IT bits when invoking a signal handler

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Submitter Peter Maydell
Date Jan. 10, 2011, 11:11 p.m.
Message ID <1294701112-14071-4-git-send-email-peter.maydell@linaro.org>
Download mbox | patch
Permalink /patch/78255/
State New
Headers show

Comments

Peter Maydell - Jan. 10, 2011, 11:11 p.m.
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(-)
Aurelien Jarno - Jan. 11, 2011, 11:09 p.m.
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
> 
> 
>

Patch

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;
 }