* linux-user/armeb: Fix __kernel_cmpxchg() for armeb
@ 2023-07-27 21:19 Helge Deller
2023-07-28 0:12 ` Richard Henderson
2023-07-31 9:26 ` Philippe Mathieu-Daudé
0 siblings, 2 replies; 4+ messages in thread
From: Helge Deller @ 2023-07-27 21:19 UTC (permalink / raw)
To: Richard Henderson, Laurent Vivier, qemu-devel, Peter Maydell
Cc: John Reiser, Markus F.X.J. Oberhumer
Words are stored in big endian in the guest memory for armeb.
Commit 7f4f0d9ea870 ("linux-user/arm: Implement __kernel_cmpxchg with
host atomics") switched to use qatomic_cmpxchg() to swap a word with the
memory content, but missed to endianess-swap the oldval and newval
values when emulating an armeb CPU.
The bug can be verified with qemu >= v7.2 on any little-endian host,
when starting the armeb binary of the upx program, which just hangs
without this patch.
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: qemu-stable@nongnu.org
Reported-by: "Markus F.X.J. Oberhumer" <markus@oberhumer.com>
Reported-by: John Reiser <jreiser@BitWagon.com>
Closes: https://github.com/upx/upx/issues/687
diff --git a/linux-user/arm/cpu_loop.c b/linux-user/arm/cpu_loop.c
index a992423257..ff0bff7c63 100644
--- a/linux-user/arm/cpu_loop.c
+++ b/linux-user/arm/cpu_loop.c
@@ -117,8 +117,8 @@ static void arm_kernel_cmpxchg32_helper(CPUARMState *env)
{
uint32_t oldval, newval, val, addr, cpsr, *host_addr;
- oldval = env->regs[0];
- newval = env->regs[1];
+ oldval = tswap32(env->regs[0]);
+ newval = tswap32(env->regs[1]);
addr = env->regs[2];
mmap_lock();
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: linux-user/armeb: Fix __kernel_cmpxchg() for armeb
2023-07-27 21:19 linux-user/armeb: Fix __kernel_cmpxchg() for armeb Helge Deller
@ 2023-07-28 0:12 ` Richard Henderson
2023-07-31 9:26 ` Philippe Mathieu-Daudé
1 sibling, 0 replies; 4+ messages in thread
From: Richard Henderson @ 2023-07-28 0:12 UTC (permalink / raw)
To: Helge Deller, Laurent Vivier, qemu-devel, Peter Maydell
Cc: John Reiser, Markus F.X.J. Oberhumer
On 7/27/23 14:19, Helge Deller wrote:
> Words are stored in big endian in the guest memory for armeb.
>
> Commit 7f4f0d9ea870 ("linux-user/arm: Implement __kernel_cmpxchg with
> host atomics") switched to use qatomic_cmpxchg() to swap a word with the
> memory content, but missed to endianess-swap the oldval and newval
> values when emulating an armeb CPU.
>
> The bug can be verified with qemu >= v7.2 on any little-endian host,
> when starting the armeb binary of the upx program, which just hangs
> without this patch.
>
> Signed-off-by: Helge Deller <deller@gmx.de>
> Cc: Richard Henderson <richard.henderson@linaro.org>
> Cc: Peter Maydell <peter.maydell@linaro.org>
> Cc: qemu-stable@nongnu.org
> Reported-by: "Markus F.X.J. Oberhumer" <markus@oberhumer.com>
> Reported-by: John Reiser <jreiser@BitWagon.com>
> Closes: https://github.com/upx/upx/issues/687
>
> diff --git a/linux-user/arm/cpu_loop.c b/linux-user/arm/cpu_loop.c
> index a992423257..ff0bff7c63 100644
> --- a/linux-user/arm/cpu_loop.c
> +++ b/linux-user/arm/cpu_loop.c
> @@ -117,8 +117,8 @@ static void arm_kernel_cmpxchg32_helper(CPUARMState *env)
> {
> uint32_t oldval, newval, val, addr, cpsr, *host_addr;
>
> - oldval = env->regs[0];
> - newval = env->regs[1];
> + oldval = tswap32(env->regs[0]);
> + newval = tswap32(env->regs[1]);
> addr = env->regs[2];
There's a similar bug with arm_kernel_cmpxchg64_helper just below, but
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
as far as this goes.
r~
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: linux-user/armeb: Fix __kernel_cmpxchg() for armeb
2023-07-27 21:19 linux-user/armeb: Fix __kernel_cmpxchg() for armeb Helge Deller
2023-07-28 0:12 ` Richard Henderson
@ 2023-07-31 9:26 ` Philippe Mathieu-Daudé
2023-07-31 9:29 ` Michael Tokarev
1 sibling, 1 reply; 4+ messages in thread
From: Philippe Mathieu-Daudé @ 2023-07-31 9:26 UTC (permalink / raw)
To: Helge Deller, Richard Henderson, Laurent Vivier, qemu-devel,
Peter Maydell
Cc: John Reiser, Markus F.X.J. Oberhumer
On 27/7/23 23:19, Helge Deller wrote:
> Words are stored in big endian in the guest memory for armeb.
>
> Commit 7f4f0d9ea870 ("linux-user/arm: Implement __kernel_cmpxchg with
> host atomics") switched to use qatomic_cmpxchg() to swap a word with the
> memory content, but missed to endianess-swap the oldval and newval
> values when emulating an armeb CPU.
>
> The bug can be verified with qemu >= v7.2 on any little-endian host,
> when starting the armeb binary of the upx program, which just hangs
> without this patch.
>
> Signed-off-by: Helge Deller <deller@gmx.de>
> Cc: Richard Henderson <richard.henderson@linaro.org>
> Cc: Peter Maydell <peter.maydell@linaro.org>
> Cc: qemu-stable@nongnu.org
> Reported-by: "Markus F.X.J. Oberhumer" <markus@oberhumer.com>
> Reported-by: John Reiser <jreiser@BitWagon.com>
> Closes: https://github.com/upx/upx/issues/687
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: linux-user/armeb: Fix __kernel_cmpxchg() for armeb
2023-07-31 9:26 ` Philippe Mathieu-Daudé
@ 2023-07-31 9:29 ` Michael Tokarev
0 siblings, 0 replies; 4+ messages in thread
From: Michael Tokarev @ 2023-07-31 9:29 UTC (permalink / raw)
To: Philippe Mathieu-Daudé,
Helge Deller, Richard Henderson, Laurent Vivier, qemu-devel,
Peter Maydell
Cc: John Reiser, Markus F.X.J. Oberhumer
31.07.2023 12:26, Philippe Mathieu-Daudé wrote:
> On 27/7/23 23:19, Helge Deller wrote:
>> Words are stored in big endian in the guest memory for armeb.
..
> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
There was a v3 of this patch already, fwiw.
/mjt
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2023-07-31 9:30 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2023-07-27 21:19 linux-user/armeb: Fix __kernel_cmpxchg() for armeb Helge Deller
2023-07-28 0:12 ` Richard Henderson
2023-07-31 9:26 ` Philippe Mathieu-Daudé
2023-07-31 9:29 ` Michael Tokarev
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