RE: [PATCH v2] gdbserver: Clear X86_XSTATE_MPX bits in xcr0 on x32

["Willgerodt, Felix" <felix.willgerodt@intel.com>]

> -----Original Message-----
> From: H.J. Lu <hjl.tools@gmail.com>
> Sent: Mittwoch, 20. März 2024 12:13
> To: gdb-patches@sourceware.org
> Cc: Willgerodt, Felix <felix.willgerodt@intel.com>; jhb@FreeBSD.org
> Subject: [PATCH v2] gdbserver: Clear X86_XSTATE_MPX bits in xcr0 on x32
> 
> Since MPX isn't available for x32, we should clear X86_XSTATE_MPX bits
> on x32.
> 
> 	PR server/31511
> 	* linux-x86-low.cc (x86_linux_read_description): Clear
> 	X86_XSTATE_MPX bits in xcr0 on x32.
> ---
>  gdbserver/linux-x86-low.cc | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/gdbserver/linux-x86-low.cc b/gdbserver/linux-x86-low.cc
> index 3af0a009052..933d1fb012a 100644
> --- a/gdbserver/linux-x86-low.cc
> +++ b/gdbserver/linux-x86-low.cc
> @@ -938,6 +938,10 @@ x86_linux_read_description (void)
>  	  xcr0 = xstateregs[(I386_LINUX_XSAVE_XCR0_OFFSET
>  			     / sizeof (uint64_t))];
> 
> +	  /* No MPX on x32.  */
> +	  if (machine == EM_X86_64 && !is_elf64)
> +	    xcr0 &= ~X86_XSTATE_MPX;
> +
>  	  xsave_len = x86_xsave_length ();
> 
>  	  /* Use PTRACE_GETREGSET if it is available.  */
> --
> 2.44.0

+1 from me.

Reviewed-by: Felix Willgerodt <felix.willgerodt@intel.com>

Regards,
Felix
Intel Deutschland GmbH
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