Re: [PATCH 1/3] i386-fbsd-nat: Assume PT_GETXMMREGS is present.

[John Baldwin <jhb@FreeBSD.org>]

On 3/1/22 6:22 AM, Simon Marchi wrote:
> 
> 
> On 2022-02-28 17:35, John Baldwin wrote:
>> PT_GETXMMREGS was first added in FreeBSD 6.0 released in November 2005.
>> The last FreeBSD release without support was 5.5 released in May 2006.
>> ---
>>   gdb/i386-fbsd-nat.c | 14 --------------
>>   1 file changed, 14 deletions(-)
>>
>> diff --git a/gdb/i386-fbsd-nat.c b/gdb/i386-fbsd-nat.c
>> index 6fb67434a2d..a6ced66250c 100644
>> --- a/gdb/i386-fbsd-nat.c
>> +++ b/gdb/i386-fbsd-nat.c
>> @@ -42,9 +42,7 @@ class i386_fbsd_nat_target final
>>     void fetch_registers (struct regcache *, int) override;
>>     void store_registers (struct regcache *, int) override;
>>   
>> -#if defined(PT_GETXMMREGS) || defined(PT_GETXSTATE_INFO)
>>     const struct target_desc *read_description () override;
>> -#endif
>>   
>>     void resume (ptid_t, int, enum gdb_signal) override;
>>   
>> @@ -59,9 +57,7 @@ static i386_fbsd_nat_target the_i386_fbsd_nat_target;
>>   static size_t xsave_len;
>>   #endif
>>   
>> -#ifdef HAVE_PT_GETXMMREGS
>>   static int have_ptrace_xmmregs;
> 
> Is this variable (have_ptrace_xmmregs) still relevant?  In other words,
> can the PT_GETXMMREGS request legitimately fail?

Yes, while the ptrace op always exists, it only works if the running CPU supports
SSE (and this is true in i386-bsd-nat.c as well).  Granted, the number of systems
running modern BSD operating systems on a CPU that doesn't include SSE support
(think Pentium or Pentium Pro class CPUs) may be vanishingly small to the point
of zero.

-- 
John Baldwin