[PATCHv5 08/11] gdb/arch: assert that X86_XSTATE_MPX is not set for x32

[Andrew Burgess]

"Willgerodt, Felix" <felix.willgerodt@intel.com> writes:

>> -----Original Message-----
>> From: Andrew Burgess <aburgess@redhat.com>
>> Sent: Freitag, 26. April 2024 17:02
>> To: gdb-patches@sourceware.org
>> Cc: Andrew Burgess <aburgess@redhat.com>; Willgerodt, Felix
>> <felix.willgerodt@intel.com>; John Baldwin <jhb@FreeBSD.org>
>> Subject: [PATCHv5 08/11] gdb/arch: assert that X86_XSTATE_MPX is not set for
>> x32
>> 
>> While rebasing this series past this commit:
>> 
>>   commit 4bb20a6244b7091a9a7a2ae35dfbd7e8db27550a
>>   Date:   Wed Mar 20 04:13:18 2024 -0700
>> 
>>       gdbserver: Clear X86_XSTATE_MPX bits in xcr0 on x32
>> 
>> I worried that there could be other paths that might result in an xcr0
>> value which has X86_XSTATE_MPX set in x32 mode.  As everyone
>> eventually calls amd64_create_target_description to build their target
>> description, I figured we could assert in here that if X86_XSTATE_MPX
>> is set then we should not be an x32 target, this will uncover any
>> other bugs in this area.
>> 
>> I'm not currently able to build/run any x32 binaries, so I have no way
>> to test this, but the author of commit 4bb20a6244b7091 did test this
>> series with that assert in place and didn't see any problems.
>> 
>> Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31511
>> ---
>>  gdb/arch/amd64.c | 8 ++++++--
>>  1 file changed, 6 insertions(+), 2 deletions(-)
>> 
>
> GDB was also checking this somewhere when I reviewed H.J.'s patch.
> Though it doesn't hurt to have it here in my eyes.
>
> Approved-By: Felix Willgerodt <felix.willgerodt@intel.com>

As this commit is only loosely tied to the rest of the series I've gone
ahead and pushed this to upstream.

Thanks,
Andrew