Re: [PATCH v2 1/1] target/ppc: don't byte swap ELFv2 signal handler

[Richard Henderson]

On 3/18/20 10:01 AM, Vincent Fazio wrote:
> From: Vincent Fazio <address@hidden>
> 
> 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 <address@hidden>
> Reviewed-by: Laurent Vivier <address@hidden>
> ---
> Changes since v1:
> - Drop host/target endianness callouts
> - Drop unnecessary pointer cast
> - Clarify commit message

Reviewed-by: Richard Henderson <address@hidden>


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