[PATCH v3 0/2] arm64 live patching

[Torsten Duwe]

V3, including suggestions from the replies and 2 fixes.

Reminder: make sure you have a prolog-pad gcc, and this in your
top level Makefile:

ifdef CONFIG_LIVEPATCH
KBUILD_CFLAGS	+= $(call cc-option,-fno-ipa-ra)
endif

Tested with v4.8-rc1 + gcc-6.1

Changes since v2:
  * Do not skip initial NOP conversion for CC_USING_PROLOG_PAD,
    in other words: don't introduce new #ifdefs into generic code.
    (as requested by Steven Rostedt after my intermediate suggestion)
    Instead, check in arm64 whether a call to mcount is to be NOPed,
    and be strict again about the expected "old" instructions.
  * issue a warning should the compiler not know about -fprolog-pad=
    (as suggested by Josh Poimboeuf)
    Only strip the compiler flag proper, not the cpp flag, for critical
    files.
  * fix thinko / bummer in live patch return address change detection.
    Skip the graph caller if the addresses are _not_ equal!

Changes since v1:
  * instead of a comment "should be CC_USING_PROLOG_PAD":
    do it. CC_FLAGS_FTRACE holds it now, and the IPA
    disabler has become a separate issue (see above).

Torsten Duwe (2):
  arm64: implement FTRACE_WITH_REGS
  arm64: implement live patching

 arch/arm64/Kconfig                 |   4 ++
 arch/arm64/Makefile                |   9 ++++
 arch/arm64/include/asm/ftrace.h    |   8 +++
 arch/arm64/include/asm/livepatch.h |  37 ++++++++++++++
 arch/arm64/kernel/Makefile         |   6 +--
 arch/arm64/kernel/entry-ftrace.S   | 102 +++++++++++++++++++++++++++++++++++++
 arch/arm64/kernel/ftrace.c         |  45 ++++++++++++++--
 include/asm-generic/vmlinux.lds.h  |   2 +-
 include/linux/compiler.h           |   4 ++
 9 files changed, 209 insertions(+), 8 deletions(-)
 create mode 100644 arch/arm64/include/asm/livepatch.h

-- 
2.6.2