perf trace augmented_syscalls: Hook into syscalls:sys_exit_SYSCALL too

Hook the pair enter/exit when using augmented_{filename,sockaddr,etc}_syscall(),
this way we'll be able to see what entries are in the ELF sections generated
from augmented_syscalls.c and filter them out from the main raw_syscalls:*
tracepoints used by 'perf trace'.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-cyav42qj5yylolw4attcw99z@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/examples/bpf/augmented_syscalls.c b/tools/perf/examples/bpf/augmented_syscalls.c
index 253b3ccbd17da44ee93553a2bca289f318809fc4..1419a9186937264c57c29aea2f050b439768f683 100644 (file)
--- a/tools/perf/examples/bpf/augmented_syscalls.c
+++ b/tools/perf/examples/bpf/augmented_syscalls.c
@@ -26,6 +26,12 @@ struct bpf_map SEC("maps") __augmented_syscalls__ = {
        .max_entries = __NR_CPUS__,
 };
 
+struct syscall_exit_args {
+       unsigned long long common_tp_fields;
+       long               syscall_nr;
+       long               ret;
+};
+
 struct augmented_filename {
        int     size;
        int     reserved;
@@ -49,6 +55,10 @@ int syscall_enter(syscall)(struct syscall_enter_##syscall##_args *args)                              \
                          (sizeof(augmented_args) - sizeof(augmented_args.filename.value) +     \
                           augmented_args.filename.size));                                      \
        return 0;                                                                               \
+}                                                                                              \
+int syscall_exit(syscall)(struct syscall_exit_args *args)                                      \
+{                                                                                              \
+       return 1; /* 0 as soon as we start copying data returned by the kernel, e.g. 'read' */  \
 }
 
 struct syscall_enter_openat_args {
@@ -116,6 +126,10 @@ int syscall_enter(syscall)(struct syscall_enter_##syscall##_args *args)                            \
                          &augmented_args,                                                      \
                          sizeof(augmented_args) - sizeof(augmented_args.addr) + addrlen);      \
        return 0;                                                                               \
+}                                                                                              \
+int syscall_exit(syscall)(struct syscall_exit_args *args)                                      \
+{                                                                                              \
+       return 1; /* 0 as soon as we start copying data returned by the kernel, e.g. 'read' */  \
 }
 
 struct sockaddr;