diff options
| author | Yonghong Song <yhs@fb.com> | 2017-08-04 16:00:09 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-08-07 14:09:48 -0700 |
| commit | cf5f5cea270655dd49370760576c64b228583b79 (patch) | |
| tree | 5758e9d56b94542d082d40ed66f8d8effa6287f9 /include/linux/syscalls.h | |
| parent | d226a2b84d0528da7e35e7e19e052293889cdd21 (diff) | |
bpf: add support for sys_enter_* and sys_exit_* tracepoints
Currently, bpf programs cannot be attached to sys_enter_* and sys_exit_*
style tracepoints. The iovisor/bcc issue #748
(https://github.com/iovisor/bcc/issues/748) documents this issue.
For example, if you try to attach a bpf program to tracepoints
syscalls/sys_enter_newfstat, you will get the following error:
# ./tools/trace.py t:syscalls:sys_enter_newfstat
Ioctl(PERF_EVENT_IOC_SET_BPF): Invalid argument
Failed to attach BPF to tracepoint
The main reason is that syscalls/sys_enter_* and syscalls/sys_exit_*
tracepoints are treated differently from other tracepoints and there
is no bpf hook to it.
This patch adds bpf support for these syscalls tracepoints by
. permitting bpf attachment in ioctl PERF_EVENT_IOC_SET_BPF
. calling bpf programs in perf_syscall_enter and perf_syscall_exit
The legality of bpf program ctx access is also checked.
Function trace_event_get_offsets returns correct max offset for each
specific syscall tracepoint, which is compared against the maximum offset
access in bpf program.
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/syscalls.h')
| -rw-r--r-- | include/linux/syscalls.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 3cb15ea48aee..c9170218e9e6 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -172,8 +172,20 @@ extern struct trace_event_functions exit_syscall_print_funcs; static struct syscall_metadata __used \ __attribute__((section("__syscalls_metadata"))) \ *__p_syscall_meta_##sname = &__syscall_meta_##sname; + +static inline int is_syscall_trace_event(struct trace_event_call *tp_event) +{ + return tp_event->class == &event_class_syscall_enter || + tp_event->class == &event_class_syscall_exit; +} + #else #define SYSCALL_METADATA(sname, nb, ...) + +static inline int is_syscall_trace_event(struct trace_event_call *tp_event) +{ + return 0; +} #endif #define SYSCALL_DEFINE0(sname) \ |