This patchset enables livepatch support on arm64.
Livepatch was merged in v4.0, and allows replacying a function dynamically based on ftrace framework, but it also requires -mfentry option of gcc. Currently arm64 gcc doesn't support it, but by adding a helper function to ftrace, we will be able to support livepatch on arch's which don't support this option.
I submit this patchset as RFC since I'm not quite sure that I'm doing in the right way, or we should definitely support -fentry instead.
Please note that I tested the feature only with livepatch-sample, and the code for DYNAMIC_TRACE_WITH_REGS is still rough-edged.
To: Steven Rostedt rostedt@goodmis.org To: Ingo Molnar mingo@kernel.org To: Josh Poimboeuf jpoimboe@redhat.com To: Seth Jennings sjenning@redhat.com To: Jiri Kosina jkosina@suse.cz To: Vojtech Pavlik vojtech@suse.cz To: Catalin Marinas catalin.marinas@arm.com To: Will Deacon will.deacon@arm.com
AKASHI Takahiro (4): ftrace: add a helper function for livepatch livepatch: adjust a patched function's address arm64: ftrace: add DYNAMIC_TRACE_WITH_REGS version arm64: add livepatch support
arch/arm64/Kconfig | 4 ++ arch/arm64/include/asm/ftrace.h | 4 ++ arch/arm64/include/asm/livepatch.h | 38 +++++++++++ arch/arm64/kernel/Makefile | 1 + arch/arm64/kernel/entry-ftrace.S | 124 ++++++++++++++++++++++++++++++++++++ arch/arm64/kernel/ftrace.c | 24 ++++++- arch/arm64/kernel/livepatch.c | 68 ++++++++++++++++++++ arch/x86/include/asm/livepatch.h | 5 ++ include/linux/ftrace.h | 2 + include/linux/livepatch.h | 2 + kernel/livepatch/core.c | 16 +++-- kernel/trace/ftrace.c | 26 ++++++++ 12 files changed, 309 insertions(+), 5 deletions(-) create mode 100644 arch/arm64/include/asm/livepatch.h create mode 100644 arch/arm64/kernel/livepatch.c