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