From: Richard Henderson <richard.henderson@linaro.org>
To: Vincent Fazio <vfazio@xes-inc.com>, qemu-devel@nongnu.org
Cc: qemu-trivial@nongnu.org, Riku Voipio <riku.voipio@iki.fi>,
Laurent Vivier <laurent@vivier.eu>,
qemu-ppc@nongnu.org, Vincent Fazio <vfazio@gmail.com>,
David Gibson <david@gibson.dropbear.id.au>
Subject: Re: [PATCH v2 1/1] target/ppc: don't byte swap ELFv2 signal handler
Date: Wed, 18 Mar 2020 12:57:30 -0700 [thread overview]
Message-ID: <8d76e1bf-2149-b995-3257-fd40eca6ccf9@linaro.org> (raw)
In-Reply-To: <20200318170116.1922-1-vfazio@xes-inc.com>
On 3/18/20 10:01 AM, Vincent Fazio wrote:
> From: Vincent Fazio <vfazio@gmail.com>
>
> Previously, the signal handler would be byte swapped if the target and
> host CPU used different endianness. This would cause a SIGSEGV when
> attempting to translate the opcode pointed to by the swapped address.
>
> Thread 1 "qemu-ppc64" received signal SIGSEGV, Segmentation fault.
> 0x00000000600a9257 in ldl_he_p (ptr=0x4c2c061000000000) at qemu/include/qemu/bswap.h:351
> 351 __builtin_memcpy(&r, ptr, sizeof(r));
>
> #0 0x00000000600a9257 in ldl_he_p (ptr=0x4c2c061000000000) at qemu/include/qemu/bswap.h:351
> #1 0x00000000600a92fe in ldl_be_p (ptr=0x4c2c061000000000) at qemu/include/qemu/bswap.h:449
> #2 0x00000000600c0790 in translator_ldl_swap at qemu/include/exec/translator.h:201
> #3 0x000000006011c1ab in ppc_tr_translate_insn at qemu/target/ppc/translate.c:7856
> #4 0x000000006005ae70 in translator_loop at qemu/accel/tcg/translator.c:102
>
> Now, no swap is performed and execution continues properly.
>
> Signed-off-by: Vincent Fazio <vfazio@gmail.com>
> Reviewed-by: Laurent Vivier <laurent@vivier.eu>
> ---
> Changes since v1:
> - Drop host/target endianness callouts
> - Drop unnecessary pointer cast
> - Clarify commit message
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
r~
next prev parent reply other threads:[~2020-03-18 19:58 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-18 17:01 [PATCH v2 1/1] target/ppc: don't byte swap ELFv2 signal handler Vincent Fazio
2020-03-18 19:57 ` Richard Henderson [this message]
2020-03-19 5:35 ` David Gibson
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