linux-kernel - [PATCH v2 0/9] livepatch,module: Remove .klp.arch and module_disable

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Message-Id: <cover.1587131959.git.jpoimboe@redhat.com>
Date:   Fri, 17 Apr 2020 09:04:25 -0500
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     live-patching@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Peter Zijlstra <peterz@...radead.org>,
        Jessica Yu <jeyu@...nel.org>
Subject: [PATCH v2 0/9] livepatch,module: Remove .klp.arch and module_disable_ro()

v2:
- add vmlinux.ko check [peterz]
- remove 'klp_object' forward declaration [mbenes]
- use text_mutex [jeyu]
- fix documentation TOC [jeyu]
- fix s390 issues [mbenes]
- upstream kpatch-build now supports this
  (though it's only enabled for Linux >= 5.8)

These patches add simplifications and improvements for some issues Peter
found six months ago, as part of his non-writable text code (W^X)
cleanups.

Highlights:

- Remove the livepatch arch-specific .klp.arch sections, which were used
  to do paravirt patching and alternatives patching for livepatch
  replacement code.

- Add support for jump labels in patched code.

- Remove the last module_disable_ro() usage.

For more background, see this thread:

  https://lkml.kernel.org/r/20191021135312.jbbxsuipxldocdjk@treble

I've tested this with a modified kpatch-build:

  https://github.com/jpoimboe/kpatch/tree/no-klp-arch

(I'm planning to submit a github PR for kpatch-build, once I get
 the updated unit/integration tests sorted out.



Josh Poimboeuf (6):
  livepatch: Disallow vmlinux.ko
  livepatch: Apply vmlinux-specific KLP relocations early
  livepatch: Prevent module-specific KLP rela sections from referencing
    vmlinux symbols
  s390: Change s390_kernel_write() return type to match memcpy()
  livepatch: Remove module_disable_ro() usage
  module: Remove module_disable_ro()

Peter Zijlstra (3):
  livepatch: Remove .klp.arch
  s390/module: Use s390_kernel_write() for late relocations
  x86/module: Use text_poke() for late relocations

 Documentation/livepatch/module-elf-format.rst |  15 +-
 arch/s390/include/asm/uaccess.h               |   2 +-
 arch/s390/kernel/module.c                     | 125 ++++++++++------
 arch/s390/mm/maccess.c                        |   9 +-
 arch/um/kernel/um_arch.c                      |  16 +++
 arch/x86/kernel/Makefile                      |   1 -
 arch/x86/kernel/livepatch.c                   |  53 -------
 arch/x86/kernel/module.c                      |  43 +++++-
 include/linux/livepatch.h                     |  17 ++-
 include/linux/module.h                        |   2 -
 kernel/livepatch/core.c                       | 133 +++++++++++-------
 kernel/module.c                               |  22 +--
 12 files changed, 243 insertions(+), 195 deletions(-)
 delete mode 100644 arch/x86/kernel/livepatch.c

-- 
2.21.1