[rfc] bi-arch for x86-64 corefile.

[H.J. Lu]

On Mon, Oct 29, 2012 at 9:29 PM, Yao Qi <yao@codesourcery.com> wrote:
> [add binutils@sourceware.org back to CC]
>
>
> On 10/30/2012 10:51 AM, H.J. Lu wrote:
>>
>>  >>> >+    int pr_fpvalid;                    /* True if math copro
>> being used.  */
>>  >>> >+#if __WORDSIZE == 32
>>  >>> >+    char pad[4];
>>  >>> >+#endif
>>  >>> >+  };
>>  >>
>>  >> This is wrong. There should be no pad.  Please properly copy the
>>  >> 64-bit elf_prstatus.
>>  >>
>>  >
>>  > Without this pad, the size of 'struct elf_prstatus64' on 32-bit(332)
>> is not equal to the size of 'struct elf_prstatus' on 64-bit(336).  IIUC,
>> the goal of defining 'elf_prstatus64' is to emulate 64-bit
>> 'elf_prstatus' on 32-bit machine.  The field 'pad' is for tail padding,
>> as the size of this struct should be multiple of 8.
>>
>> It won't work for x32.
>>
>
> H.J, I am confused here.  I assume you mean x32 as target.  Now, both
> 'prstatus64_t' and 'prpsinfo64_t' are only used in
> elf64-x86-64.c:elf_x86_64_write_core_note ([1] and [2] as annotated below),
>
> elf_x86_64_write_core_note (....)
> {
>   switch (note_type)
>     case NT_PRPSINFO:
>       if (bed->s->elfclass == ELFCLASS32)
>         {
>           prpsinfo32_t data;  <--- [3]
>         }
>       else
>         {
>           prpsinfo64_t data;  <---- [1]
>         }
>     case NT_PRSTATUS:
>       if (bed->s->elfclass == ELFCLASS32)
>         {
>           if (bed->elf_machine_code == EM_X86_64)
>             {
>               prstatusx32_t prstat;  <--- [4]
>             }
>           else
>             {
>               prstatus32_t prstat;
>             }
>         }
>       else
>         {
>           prstatus64_t prstat;   <--- [2]
>         }
>     }
> }
>
> x32 will go the path [3] and [4], unreachable to [1] and [2].  so this patch
> shouldn't affect x32 as target.
>

I am checking in this.  But sourceware.org times out for me.  Please
give it a try.

-- 
H.J.
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