hi, as part of the effort on speeding up the uprobes [0] coming with return uprobe optimization by using syscall instead of the trap on the uretprobe trampoline. The speed up depends on instruction type that uprobe is installed and depends on specific HW type, please check patch 1 for details. I added extra bpf selftest to check on registers values before and after uretprobe to make sure the syscall saves all the needed regs. reasons for this being RFC: - I'm not sure we want specific uretprobe syscall and not generic uprobe syscall to extend in future.. when I added extra code to read registers from stack I did not see any notable performance degradation, so I think we could survive restoring another register for argument - I'm not sure how we want to handle assembly code in bpf selftests thanks, jirka [0] https://lore.kernel.org/bpf/ZeCXHKJ--iYYbmLj@krava/ --- Jiri Olsa (3): uprobe: Add uretprobe syscall to speed up return probe selftests/bpf: Add uretprobe syscall test selftests/bpf: Mark uprobe trigger functions with nocf_check attribute arch/x86/entry/syscalls/syscall_64.tbl | 1 + arch/x86/kernel/uprobes.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/syscalls.h | 2 ++ include/linux/uprobes.h | 2 ++ include/uapi/asm-generic/unistd.h | 5 ++++- kernel/events/uprobes.c | 18 ++++++++++++++---- kernel/sys_ni.c | 2 ++ tools/include/linux/compiler.h | 4 ++++ tools/testing/selftests/bpf/Makefile | 15 +++++++++++++-- tools/testing/selftests/bpf/benchs/bench_trigger.c | 6 +++--- tools/testing/selftests/bpf/prog_tests/arch/x86/uprobe_syscall.S | 89 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ tools/testing/selftests/bpf/progs/uprobe_syscall.c | 15 +++++++++++++++ 13 files changed, 281 insertions(+), 10 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/arch/x86/uprobe_syscall.S create mode 100644 tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c create mode 100644 tools/testing/selftests/bpf/progs/uprobe_syscall.c
