Re: [PATCH] linux-user/elfload: byteswap i386 registers when dumping core

[Laurent Vivier]

Le 03/08/2021 à 19:20, Ilya Leoshkevich a écrit :
> Core dumps from emulating x86_64 on big-endian hosts contain incorrect
> register values.
> 
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
> ---
>  linux-user/elfload.c | 88 ++++++++++++++++++++++----------------------
>  1 file changed, 44 insertions(+), 44 deletions(-)
> 
> diff --git a/linux-user/elfload.c b/linux-user/elfload.c
> index 42ef2a1148..01e9a833fb 100644
> --- a/linux-user/elfload.c
> +++ b/linux-user/elfload.c
> @@ -172,33 +172,33 @@ typedef target_elf_greg_t  
> target_elf_gregset_t[ELF_NREG];
>   */
>  static void elf_core_copy_regs(target_elf_gregset_t *regs, const CPUX86State 
> *env)
>  {
> -    (*regs)[0] = env->regs[15];
> -    (*regs)[1] = env->regs[14];
> -    (*regs)[2] = env->regs[13];
> -    (*regs)[3] = env->regs[12];
> -    (*regs)[4] = env->regs[R_EBP];
> -    (*regs)[5] = env->regs[R_EBX];
> -    (*regs)[6] = env->regs[11];
> -    (*regs)[7] = env->regs[10];
> -    (*regs)[8] = env->regs[9];
> -    (*regs)[9] = env->regs[8];
> -    (*regs)[10] = env->regs[R_EAX];
> -    (*regs)[11] = env->regs[R_ECX];
> -    (*regs)[12] = env->regs[R_EDX];
> -    (*regs)[13] = env->regs[R_ESI];
> -    (*regs)[14] = env->regs[R_EDI];
> -    (*regs)[15] = env->regs[R_EAX]; /* XXX */
> -    (*regs)[16] = env->eip;
> -    (*regs)[17] = env->segs[R_CS].selector & 0xffff;
> -    (*regs)[18] = env->eflags;
> -    (*regs)[19] = env->regs[R_ESP];
> -    (*regs)[20] = env->segs[R_SS].selector & 0xffff;
> -    (*regs)[21] = env->segs[R_FS].selector & 0xffff;
> -    (*regs)[22] = env->segs[R_GS].selector & 0xffff;
> -    (*regs)[23] = env->segs[R_DS].selector & 0xffff;
> -    (*regs)[24] = env->segs[R_ES].selector & 0xffff;
> -    (*regs)[25] = env->segs[R_FS].selector & 0xffff;
> -    (*regs)[26] = env->segs[R_GS].selector & 0xffff;
> +    (*regs)[0] = tswapreg(env->regs[15]);
> +    (*regs)[1] = tswapreg(env->regs[14]);
> +    (*regs)[2] = tswapreg(env->regs[13]);
> +    (*regs)[3] = tswapreg(env->regs[12]);
> +    (*regs)[4] = tswapreg(env->regs[R_EBP]);
> +    (*regs)[5] = tswapreg(env->regs[R_EBX]);
> +    (*regs)[6] = tswapreg(env->regs[11]);
> +    (*regs)[7] = tswapreg(env->regs[10]);
> +    (*regs)[8] = tswapreg(env->regs[9]);
> +    (*regs)[9] = tswapreg(env->regs[8]);
> +    (*regs)[10] = tswapreg(env->regs[R_EAX]);
> +    (*regs)[11] = tswapreg(env->regs[R_ECX]);
> +    (*regs)[12] = tswapreg(env->regs[R_EDX]);
> +    (*regs)[13] = tswapreg(env->regs[R_ESI]);
> +    (*regs)[14] = tswapreg(env->regs[R_EDI]);
> +    (*regs)[15] = tswapreg(env->regs[R_EAX]); /* XXX */
> +    (*regs)[16] = tswapreg(env->eip);
> +    (*regs)[17] = tswapreg(env->segs[R_CS].selector & 0xffff);
> +    (*regs)[18] = tswapreg(env->eflags);
> +    (*regs)[19] = tswapreg(env->regs[R_ESP]);
> +    (*regs)[20] = tswapreg(env->segs[R_SS].selector & 0xffff);
> +    (*regs)[21] = tswapreg(env->segs[R_FS].selector & 0xffff);
> +    (*regs)[22] = tswapreg(env->segs[R_GS].selector & 0xffff);
> +    (*regs)[23] = tswapreg(env->segs[R_DS].selector & 0xffff);
> +    (*regs)[24] = tswapreg(env->segs[R_ES].selector & 0xffff);
> +    (*regs)[25] = tswapreg(env->segs[R_FS].selector & 0xffff);
> +    (*regs)[26] = tswapreg(env->segs[R_GS].selector & 0xffff);
>  }
>  
>  #else
> @@ -244,23 +244,23 @@ typedef target_elf_greg_t  
> target_elf_gregset_t[ELF_NREG];
>   */
>  static void elf_core_copy_regs(target_elf_gregset_t *regs, const CPUX86State 
> *env)
>  {
> -    (*regs)[0] = env->regs[R_EBX];
> -    (*regs)[1] = env->regs[R_ECX];
> -    (*regs)[2] = env->regs[R_EDX];
> -    (*regs)[3] = env->regs[R_ESI];
> -    (*regs)[4] = env->regs[R_EDI];
> -    (*regs)[5] = env->regs[R_EBP];
> -    (*regs)[6] = env->regs[R_EAX];
> -    (*regs)[7] = env->segs[R_DS].selector & 0xffff;
> -    (*regs)[8] = env->segs[R_ES].selector & 0xffff;
> -    (*regs)[9] = env->segs[R_FS].selector & 0xffff;
> -    (*regs)[10] = env->segs[R_GS].selector & 0xffff;
> -    (*regs)[11] = env->regs[R_EAX]; /* XXX */
> -    (*regs)[12] = env->eip;
> -    (*regs)[13] = env->segs[R_CS].selector & 0xffff;
> -    (*regs)[14] = env->eflags;
> -    (*regs)[15] = env->regs[R_ESP];
> -    (*regs)[16] = env->segs[R_SS].selector & 0xffff;
> +    (*regs)[0] = tswapreg(env->regs[R_EBX]);
> +    (*regs)[1] = tswapreg(env->regs[R_ECX]);
> +    (*regs)[2] = tswapreg(env->regs[R_EDX]);
> +    (*regs)[3] = tswapreg(env->regs[R_ESI]);
> +    (*regs)[4] = tswapreg(env->regs[R_EDI]);
> +    (*regs)[5] = tswapreg(env->regs[R_EBP]);
> +    (*regs)[6] = tswapreg(env->regs[R_EAX]);
> +    (*regs)[7] = tswapreg(env->segs[R_DS].selector & 0xffff);
> +    (*regs)[8] = tswapreg(env->segs[R_ES].selector & 0xffff);
> +    (*regs)[9] = tswapreg(env->segs[R_FS].selector & 0xffff);
> +    (*regs)[10] = tswapreg(env->segs[R_GS].selector & 0xffff);
> +    (*regs)[11] = tswapreg(env->regs[R_EAX]); /* XXX */
> +    (*regs)[12] = tswapreg(env->eip);
> +    (*regs)[13] = tswapreg(env->segs[R_CS].selector & 0xffff);
> +    (*regs)[14] = tswapreg(env->eflags);
> +    (*regs)[15] = tswapreg(env->regs[R_ESP]);
> +    (*regs)[16] = tswapreg(env->segs[R_SS].selector & 0xffff);
>  }
>  #endif
>  
> 

Applied to my linux-user-for-6.1 branch.

Thanks,
Laurent