[PATCH v2 00/10] s390: Consistent usage of text_mutex

[Heiko Carstens <hca@linux.ibm.com>]

v2:
- Use text mutex for all callers of s390_kernel_write(), and add lockdep
  checking. [Based on a review comment from Ilya Leoshkevich, and also
  Sashiko feedback]

- Note: this takes now the mutex also at places where it is technically
  not necessary (e.g. ftrace init nop patching). However this is not much
  of a difference to before, where the spinlock in s390_kernel_write()
  was always taken instead

v1:
Other architectures serialize kernel text patching with text_mutex. s390
does not: __s390_kernel_write() relies on a private spinlock, and callers
partially depend on implicit exclusion (e.g. no kprobe can be set on a
jump label).

Make s390 consistent with other architectures:

- Patches 1-3 add text_mutex to the jump_label, ftrace and bpf text
  patching paths

- Patch 4 removes the redundant spinlock from __s390_kernel_write().
  CPU serialization, previously done implicitly, is now explicit via
  sync_core()

Thanks,
Heiko

Heiko Carstens (10):
  s390/jump_label: Serialize text patching with text_mutex
  s390/ftrace: Serialize text patching with text_mutex
  s390/bpf: Serialize text patching with text_mutex
  s390/runtime-const: Serialize text patching with text_mutex
  s390/module: Serialize text patching with text_mutex
  s390/stackprotector: Serialize text patching with text_mutex
  s390/nospec-branch: Serialize text patching with text_mutex
  s390/alternative: Serialize text patching with text_mutex
  s390/uaccess: Move s390_kernel_write() to asm/text-patching.h
  s390/maccess: Remove spinlock from __s390_kernel_write()

 arch/s390/include/asm/runtime-const.h |  4 +++-
 arch/s390/include/asm/text-patching.h | 14 ++++++++++++++
 arch/s390/include/asm/uaccess.h       |  9 ---------
 arch/s390/kernel/alternative.c        |  6 +++++-
 arch/s390/kernel/ftrace.c             | 11 +++++++++++
 arch/s390/kernel/jump_label.c         |  3 ++-
 arch/s390/kernel/kprobes.c            |  4 +++-
 arch/s390/kernel/module.c             |  2 ++
 arch/s390/kernel/nospec-branch.c      |  4 ++++
 arch/s390/kernel/stackprotector.c     |  6 +++++-
 arch/s390/mm/maccess.c                |  9 ++++-----
 arch/s390/net/bpf_jit_comp.c          | 21 +++++++++++++++++----
 12 files changed, 70 insertions(+), 23 deletions(-)

-- 
2.53.0