Re: [RFA 3/5] Prec: x86 segment register support: target

Hui Zhu
2010-03-22T14:44:03Z

Prec i386 code is not OS special. So the base will not be OS special too.

Thanks,
Hui

On Mon, Mar 22, 2010 at 22:35, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Mon, Mar 22, 2010 at 7:02 AM, Hui Zhu <teawater@gmail.com> wrote:
>> Thanks Michael and Daniel.
>>
>> I make a patch to add base of segments registers to x86-32:
>> (gdb) info reg
>> eax            0xffffd514       -10988
>> ecx            0x1eda96c5       517641925
>> edx            0x1      1
>> ebx            0xf7fb1ff4       -134537228
>> esp            0xffffd488       0xffffd488
>> ebp            0xffffd488       0xffffd488
>> esi            0x8048510        134513936
>> edi            0x80483d0        134513616
>> eip            0x8048487        0x8048487 <main+3>
>> eflags         0x246    [ PF ZF IF ]
>> cs             0x23     35
>> ss             0x2b     43
>> ds             0x2b     43
>> es             0x2b     43
>> fs             0x0      0
>> gs             0x63     99
>> cs_base        0x0      0
>> ss_base        0x0      0
>> ds_base        0x0      0
>> es_base        0x0      0
>> fs_base        0x0      0
>> gs_base        0xf7e528d0       -135976752
>>
>> I try it in x86-32 pc and 32bit code in x86-64.  It works OK.
>>
>> Please help me review it.
>>
>> Best regards,
>> Hui
>>
>> 2010-03-22  Hui Zhu  <teawater@gmail.com>
>>
>>        * features/i386/32bit-linux.xml (org.gnu.gdb.i386.linux): Add
>>        cs_base, ss_base, ds_base, es_base, fs_base and gs_base.
>>        * i386-tdep.h (i386_segment_base_regnum): New enum.
>>        * amd64-linux-nat.c (GDT_ENTRY_TLS_MIN,
>>        GDT_ENTRY_TLS_MAX): New marco.
>>        (ps_get_thread_area): New extern.
>>        (amd64_linux_fetch_inferior_registers): Add
>>        code to get 32 bits segment registers base.
>>        * i386-linux-nat.c (GDT_ENTRY_TLS_ENTRIES,
>>        GDT_ENTRY_TLS_MIN,
>>        GDT_ENTRY_TLS_MAX): New marco.
>>        (ps_get_thread_area): New extern.
>>        (i386_linux_fetch_inferior_registers): Add
>>        code to get segment registers base.
>
> Are we going to support them on other OSes? If not,
> the contents of i386_segment_base_regnum should be
> moved to i386-linux-tdep.h and those values should
> be after
>
> /* Register number for the "orig_eax" pseudo-register.  If this
>   pseudo-register contains a value >= 0 it is interpreted as the
>   system call number that the kernel is supposed to restart.  */
> #define I386_LINUX_ORIG_EAX_REGNUM I386_SSE_NUM_REGS
>
> In any cases, they shouldn't be hard-coded to any values.
> Otherwise, it won't work with AVX, which will add more registers.
>
>
> --
> H.J.
>