Hi,
this series is the result of the discussion to the RFC patch found at [1].
The goal is to make x86' ftrace_int3_handler() not to simply skip over
the trapping instruction as this is problematic in the context of
the live patching consistency model. For details, c.f. the commit message
of [3/4] ("x86/ftrace: make ftrace_int3_handler() not to skip fops
invocation").
Everything is based on v5.1-rc6, please let me know in case you want me to
rebase on somehing else.
For x86_64, the live patching selftest added in [4/4] succeeds with this
series applied and fails without it. On 32 bits I only compile-tested.
checkpatch reports warnings about
- an overlong line in assembly -- I chose to ignore that
- MAINTAINERS perhaps needing updates due to the new files
arch/x86/kernel/ftrace_int3_stubs.S and
tools/testing/selftests/livepatch/test-livepatch-vs-ftrace.sh.
As the existing arch/x86/kernel/ftrace_{32,64}.S haven't got an
explicit entry either, this one is probably Ok? The selftest
definitely is.
Changes to the RFC patch:
- s/trampoline/stub/ to avoid confusion with the ftrace_ops' trampolines,
- use a fixed size stack kept in struct thread_info for passing the
(adjusted) ->ip values from ftrace_int3_handler() to the stubs,
- provide one stub for each of the two possible jump targets and hardcode
those,
- add the live patching selftest.
Thanks,
Nicolai
Nicolai Stange (4):
x86/thread_info: introduce ->ftrace_int3_stack member
ftrace: drop 'static' qualifier from ftrace_ops_list_func()
x86/ftrace: make ftrace_int3_handler() not to skip fops invocation
selftests/livepatch: add "ftrace a live patched function" test
arch/x86/include/asm/thread_info.h | 11 +++
arch/x86/kernel/Makefile | 1 +
arch/x86/kernel/asm-offsets.c | 8 +++
arch/x86/kernel/ftrace.c | 79 +++++++++++++++++++---
arch/x86/kernel/ftrace_int3_stubs.S | 61 +++++++++++++++++
kernel/trace/ftrace.c | 8 +--
tools/testing/selftests/livepatch/Makefile | 3 +-
.../livepatch/test-livepatch-vs-ftrace.sh | 44 ++++++++++++
8 files changed, 199 insertions(+), 16 deletions(-)
create mode 100644 arch/x86/kernel/ftrace_int3_stubs.S
create mode 100755 tools/testing/selftests/livepatch/test-livepatch-vs-ftrace.sh
--
2.13.7
