On Wed, Apr 05, 2023 at 08:02:45PM +0200, Florent Revest wrote: > 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] Catalin, Will, are you happy to pick this via the arm64 tree, or for it to go via the trace tree? We'd been assuming the former, but it looks like there'll be a (simple) merge conflict with the series adding FUNCTION_GRAPH_RETVAL: https://lore.kernel.org/lkml/cover.1680954589.git.pengdonglin@xxxxxxxxxxxxxx/ ... as both series add some definitions to arm64's asm-offsets.c in the same place, and all those additions need to be kept. Other than that, the two series are independent. IIUC Steve was hoping to take the FUNCTION_GRAPH_RETVAL series through the trace tree, and if that's still the plan, maybe both should go that way? Mark. > 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 >
