[PATCH v4 0/6] Out-of-line static calls for powerpc64 ELF V2

[Benjamin Gray <bgray@linux.ibm.com>]

Implementation of out-of-line static calls for PowerPC 64-bit ELF V2 ABI.
Static calls patch an indirect branch into a direct branch at runtime.
Out-of-line specifically has a caller directly call a trampoline, and
the trampoline gets patched to directly call the target.

Previous versions here:
V3: https://lore.kernel.org/all/20221005053234.29312-1-bgray@linux.ibm.com/
V2: https://lore.kernel.org/all/20220926064316.765967-1-bgray@linux.ibm.com/
V1: https://lore.kernel.org/all/20220916062330.430468-1-bgray@linux.ibm.com/
RFC: https://lore.kernel.org/linuxppc-dev/20220901055823.152983-1-bgray@linux.ibm.com/

Still rebased on top of
https://lore.kernel.org/all/0df84a2eea551c1d000c34c36d0c1d23cbe26a97.1664289176.git.christophe.leroy@csgroup.eu/

Changed for V4:

[1/6]
* IS_ENABLED(CONFIG_PPC64) added to patch size condition for better
  compiler optimisation

[2/6]
* Reworded message
* Refactored need r2 save expression. Parens are intentional, C operator
  precedence can be difficult to remember, especially when three different
  kinds are used in a single expression.

Benjamin Gray (6):
  powerpc/code-patching: Implement generic text patching function
  powerpc/module: Handle caller-saved TOC in module linker
  powerpc/module: Optimise nearby branches in ELF V2 ABI stub
  static_call: Move static call selftest to static_call_selftest.c
  powerpc/64: Add support for out-of-line static calls
  powerpc: Add tests for out-of-line static calls

 arch/powerpc/Kconfig                     |  26 ++-
 arch/powerpc/include/asm/code-patching.h |  30 +++
 arch/powerpc/include/asm/static_call.h   |  80 ++++++-
 arch/powerpc/kernel/Makefile             |   4 +-
 arch/powerpc/kernel/module_64.c          |  26 ++-
 arch/powerpc/kernel/static_call.c        | 183 +++++++++++++++-
 arch/powerpc/kernel/static_call_test.c   | 263 +++++++++++++++++++++++
 arch/powerpc/kernel/static_call_test.h   |  56 +++++
 arch/powerpc/lib/code-patching.c         |  73 +++++--
 kernel/Makefile                          |   1 +
 kernel/static_call_inline.c              |  43 ----
 kernel/static_call_selftest.c            |  41 ++++
 12 files changed, 753 insertions(+), 73 deletions(-)
 create mode 100644 arch/powerpc/kernel/static_call_test.c
 create mode 100644 arch/powerpc/kernel/static_call_test.h
 create mode 100644 kernel/static_call_selftest.c


base-commit: 86de6882270620777fe9cc16ece97e9ee407122c
--
2.37.3