x86/fault: #PF improvements, mostly related to USER bit [LWN.net]

From:		Andy Lutomirski <luto-AT-kernel.org>
To:		x86-AT-kernel.org
Subject:		[PATCH v2 00/14] x86/fault: #PF improvements, mostly related to USER bit
Date:		Tue, 09 Feb 2021 18:33:32 -0800
Message-ID:		<cover.1612924255.git.luto@kernel.org>
Cc:		LKML <linux-kernel-AT-vger.kernel.org>, Dave Hansen <dave.hansen-AT-linux.intel.com>, Alexei Starovoitov <ast-AT-kernel.org>, Daniel Borkmann <daniel-AT-iogearbox.net>, Yonghong Song <yhs-AT-fb.com>, Masami Hiramatsu <mhiramat-AT-kernel.org>, Andy Lutomirski <luto-AT-kernel.org>
Archive-link:		Article

This series is a whole bunch of page fault cleanups, plus a couple
of OOPS diagnostic improvements.  The overall goals are to clean up
handling of the faulting CPL, the USER bit in the error_code, and
the log messages generated by #PF OOPSes.

This series can also be seen as CET preparation.  CET introduces the
WRUSS instruction, which is the very first way for CPL 0 code to
cause a #PF fault with the USER bit set.  Let's get the page fault
code into shape before we start using WRUSS :)

Changes from v1:
 - Various changelog improvements.
 - Reorder patches (SMAP moved after SMEP)
 - Add the efi_recover_from_page_fault() patch
 - Tidy up and improve the AMD erratum detection code

Andy Lutomirski (14):
  x86/fault: Fix AMD erratum #91 errata fixup for user code
  x86/fault: Skip the AMD erratum #91 workaround on unaffected CPUs
  x86/fault: Fold mm_fault_error() into do_user_addr_fault()
  x86/fault/32: Move is_f00f_bug() to do_kern_addr_fault()
  x86/fault: Document the locking in the fault_signal_pending() path
  x86/fault: Correct a few user vs kernel checks wrt WRUSS
  x86/fault: Improve kernel-executing-user-memory handling
  x86/fault: Skip erratum #93 workaround on new CPUs
  x86/fault: Split the OOPS code out from no_context()
  x86/fault: Bypass no_context() for implicit kernel faults from
    usermode
  x86/fault: Rename no_context() to kernelmode_fixup_or_oops()
  x86/fault: Don't look for extable entries for SMEP violations
  x86/fault: Don't run fixups for SMAP violations
  x86/fault, x86/efi: Fix and rename efi_recover_from_page_fault()

 arch/x86/include/asm/efi.h     |   2 +-
 arch/x86/mm/fault.c            | 380 +++++++++++++++++++--------------
 arch/x86/platform/efi/quirks.c |  16 +-
 3 files changed, 227 insertions(+), 171 deletions(-)

-- 
2.29.2