linux-kernel - [PATCH v6 0/3] extern inline native_save

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20180621162324.36656-1-ndesaulniers@google.com>
Date:   Thu, 21 Jun 2018 09:23:21 -0700
From:   Nick Desaulniers <ndesaulniers@...gle.com>
To:     mingo@...hat.com, tglx@...utronix.de
Cc:     akpm@...ux-foundation.org, hpa@...or.com,
        linux-efi@...r.kernel.org, linux-kernel@...r.kernel.org,
        x86@...nel.org, virtualization@...ts.linux-foundation.org,
        astrachan@...gle.com, manojgupta@...gle.com, ghackmann@...gle.com,
        sedat.dilek@...il.com, tstellar@...hat.com, keescook@...gle.com,
        yamada.masahiro@...ionext.com, michal.lkml@...kovi.net,
        linux-kbuild@...r.kernel.org, geert@...ux-m68k.org,
        will.deacon@....com, mawilcox@...rosoft.com, arnd@...db.de,
        rientjes@...gle.com, acme@...hat.com, pombredanne@...b.com,
        aryabinin@...tuozzo.com, kstewart@...uxfoundation.org,
        boris.ostrovsky@...cle.com, jan.kiszka@...mens.com,
        rostedt@...dmis.org, kirill.shutemov@...ux.intel.com,
        ard.biesheuvel@...aro.org, akataria@...are.com,
        brijesh.singh@....com, caoj.fnst@...fujitsu.com,
        gregkh@...uxfoundation.org, jarkko.sakkinen@...ux.intel.com,
        jgross@...e.com, jpoimboe@...hat.com, mka@...omium.org,
        ndesaulniers@...gle.com, thomas.lendacky@....com, tweek@...gle.com,
        mjg59@...gle.com, joe@...ches.com,
        andrea.parri@...rulasolutions.com
Subject: [PATCH v6 0/3] extern inline native_save_fl for paravirt

paravirt depends on a custom calling convention (callee saved), but
expects this from a static inline function that it then forces to be
outlined. This is problematic because different compilers or flags can
then add a stack guard that violates the calling conventions.

Uses extern inline with the out-of-line definition in assembly to
prevent compilers from adding stack guards to the outlined version.

Other parts of the codebase overwrite KBUILD_CFLAGS, which is *extremely
problematic* for extern inline, as the sematics are completely the
opposite depending on what C standard is used.
http://blahg.josefsipek.net/?p=529

Changes since v5:
  Reworded commits to include Juergen's ack and switch a Suggested-by
  for Reviewed-by tag. No code changes.

Changes since v4:
  Take Arnd's and hpa's suggestions properly feature detect gnu_inline
  attribute to support gcc 4.1.

Changes since v3:
  Take Joe's suggestion to hoist __inline__ and __inline out of
  conditional block.

Changes since v2:
  Take hpa's _ASM_ARG patch into the set in order to simplify cross
  32b/64b x86 assembly and rebase my final patch to use it.  Apply
  Sedat's typo fix to commit message and sign off on it. Take Joe's
  suggestion to simplify __inline__ and __inline. Add Arnd to list of
  folks who made helpful suggestions.

Changes since v1:
  Prefer gnu_inline function attribute instead of explicitly setting C
  standard compiler flag in problematic Makefiles. We should instead
  carefully evaluate if those Makefiles should be overwriting
  KBUILD_CFLAGS at all. Dropped the previous first two patches and added
  a new first patch.

*** BLURB HERE ***

H. Peter Anvin (1):
  x86/asm: add _ASM_ARG* constants for argument registers to <asm/asm.h>

Nick Desaulniers (2):
  compiler-gcc.h: add gnu_inline to all inline declarations
  x86: paravirt: make native_save_fl extern inline

 arch/x86/include/asm/asm.h      | 59 +++++++++++++++++++++++++++++++++
 arch/x86/include/asm/irqflags.h |  2 +-
 arch/x86/kernel/Makefile        |  1 +
 arch/x86/kernel/irqflags.S      | 26 +++++++++++++++
 include/linux/compiler-gcc.h    | 29 ++++++++++++----
 5 files changed, 109 insertions(+), 8 deletions(-)
 create mode 100644 arch/x86/kernel/irqflags.S

-- 
2.18.0.rc2.346.g013aa6912e-goog