Re: [PATCH 03/22] Return X86_XSTATE_SSE_MASK instead of 0 in i386fbsd_core_read_xcr0

[Yao Qi <qiyaoltc@gmail.com>]

John Baldwin <jhb@freebsd.org> writes:

> I think this should actually be X86_XSTATE_MMX_MASK.  Core dumps on FreeBSD/i386

s/X86_XSTATE_MMX_MASK/X86_XSTATE_X87_MASK/  ?

> only include the original 387 FPU state in .reg2, they do not write
> out SSE state
> in a separate note as Linux does.
>

FAOD, the existing code (without my patches) get SSE target description
tdesc_i386 in default.  If we should use MMX target description
tdesc_i386_mmx in this case, we can change it after my patch #4, in
which i386_target_description returns tdesc_i386_mmx for X86_XSTATE_X87_MASK.

> For i386 native FreeBSD (and probably other *BSD) targets the logic needs to
> similarly be a bit more complicated, though I can help.  In particular, the
> 'static int have_ptrace_xmmregs' in i386-bsd-nat.c probably needs to be made
> non-static with an extern in 'i386-bsd-nat.h', and i386fbsd_read_description
> should try to use PT_GETXMMREGS once to probe it if it isn't set (it can just
> fetch the gdb process' registers to test the flag) and then select
> X86_XSTATE_SSE_MASK if there is no XSAVE support for PT_GETXMMREGS works,
> else use X86_XSTATE_MMX_MASK.  Other BSD's don't have a target read description
> target method, so only i386-fbsd-nat.c would need to have its method updated.
> I could always work on this as a followup.

To be clear, can I commit this patch as-is?

-- 
Yao (齐尧)