This series adds ftrace direct call support to arm64. This makes BPF tracing programs (fentry/fexit/fmod_ret/lsm) work on arm64. It is meant to be taken by the arm64 tree but it depends on the trace-direct-v6.3-rc3 tag of the linux-trace tree: git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git That tag was created by Steven Rostedt so the arm64 tree can pull the prior work this depends on. [1] Thanks to the ftrace refactoring under that tag, an ftrace_ops backing a ftrace direct call will only ever point to *one* direct call. This means we can look up the direct called trampoline address stored in the ops from the ftrace_caller trampoline in the case when the destination would be out of reach of a BL instruction at the ftrace callsite. This fixes limitations of previous attempts such as [2]. This series has been tested on arm64 with: 1- CONFIG_FTRACE_SELFTEST 2- samples/ftrace/*.ko (cf: patch 4) 3- tools/testing/selftests/bpf/test_progs (cf: patch 5) Changes since v5 [3]: - Fixed saving the fourth argument of handle_mm_fault in both the x86 (patch 3) and arm64 (as part of patch 4) "ftrace-direct-too" sample trampolines - Fixed the address of the traced function logged by some direct call samples (ftrace-direct-multi and ftrace-direct-multi-modify) by moving lr into x0 1: https://lore.kernel.org/all/ZB2Nl7fzpHoq5V20@FVFF77S0Q05N/ 2: https://lore.kernel.org/all/20220913162732.163631-1-xukuohai@xxxxxxxxxxxxxxx/ 3: https://lore.kernel.org/bpf/20230403113552.2857693-1-revest@xxxxxxxxxxxx/ Florent Revest (5): arm64: ftrace: Add direct call support arm64: ftrace: Simplify get_ftrace_plt samples: ftrace: Save required argument registers in sample trampolines arm64: ftrace: Add direct call trampoline samples support selftests/bpf: Update the tests deny list on aarch64 arch/arm64/Kconfig | 6 ++ arch/arm64/include/asm/ftrace.h | 22 +++++ arch/arm64/kernel/asm-offsets.c | 6 ++ arch/arm64/kernel/entry-ftrace.S | 90 ++++++++++++++++---- arch/arm64/kernel/ftrace.c | 46 +++++++--- samples/ftrace/ftrace-direct-modify.c | 34 ++++++++ samples/ftrace/ftrace-direct-multi-modify.c | 40 +++++++++ samples/ftrace/ftrace-direct-multi.c | 24 ++++++ samples/ftrace/ftrace-direct-too.c | 40 +++++++-- samples/ftrace/ftrace-direct.c | 24 ++++++ tools/testing/selftests/bpf/DENYLIST.aarch64 | 82 ++---------------- 11 files changed, 306 insertions(+), 108 deletions(-) -- 2.40.0.577.gac1e443424-goog
