Re: [PATCH] x86/mpx: Correctly report do_mpx_bt_fault() failures to user-space

From	Joerg Roedel <jroedel@suse.de>
Newsgroups	linux.kernel
Subject	Re: [PATCH] x86/mpx: Correctly report do_mpx_bt_fault() failures to user-space
Date	2017-04-21 14:20 +0200
Message-ID	<tyFHz-5HC-3@gated-at.bofh.it> (permalink)
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On Thu, Apr 20, 2017 at 08:45:28AM -0700, Dave Hansen wrote:
> How about doing X86_TRAP_PF?  That would at least be consistent with
> SIGBUS, which is probably the closest thing to a generic error code that
> we have.

Correct me if I am wrong, but for SIGBUS this only happens in the
page-fault path, right? And this path is indeed entered on a #PF
exception.

I see no reason to lie to user-space about the trap_nr that caused the
SIGSEGV, especially since user-space software needs to be modified to
make use of MPX, including the signal handler. So there is no risk of
introducing any incompatibility or regression, no?

	Joerg

Thread

Re: [PATCH] x86/mpx: Correctly report do_mpx_bt_fault() failures to  user-space Dave Hansen <dave.hansen@linux.intel.com> - 2017-04-17 17:40 +0200
  Re: [PATCH] x86/mpx: Correctly report do_mpx_bt_fault() failures to  user-space Joerg Roedel <jroedel@suse.de> - 2017-04-20 14:10 +0200
    Re: [PATCH] x86/mpx: Correctly report do_mpx_bt_fault() failures to  user-space Dave Hansen <dave.hansen@linux.intel.com> - 2017-04-20 17:50 +0200
      Re: [PATCH] x86/mpx: Correctly report do_mpx_bt_fault() failures to  user-space Joerg Roedel <jroedel@suse.de> - 2017-04-21 14:20 +0200
        Re: [PATCH] x86/mpx: Correctly report do_mpx_bt_fault() failures to  user-space Dave Hansen <dave.hansen@linux.intel.com> - 2017-04-21 16:40 +0200

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