diff options
| author | Peter Zijlstra | 2009-06-12 12:46:55 +0200 |
|---|---|---|
| committer | Ingo Molnar | 2009-06-12 14:28:52 +0200 |
| commit | 974802eaa1afdc87e00821df7020a2b3c6fee623 (patch) | |
| tree | b5c38bece7f4948fe9d5cf9be02a0042e0fa39f6 /tools | |
| parent | bbd36e5e6aa6f1757c84cdb406b6eb81686d14af (diff) | |
perf_counter: Add forward/backward attribute ABI compatibility
Provide for means of extending the perf_counter_attr in a 'natural' way.
We allow growing the structure by appending fields at the end by specifying
the full structure size inside it.
When a new kernel sees a smaller (old) structure, it will 0 pad the tail.
When an old kernel sees a larger (new) structure, it will verify the tail
consists of 0s, otherwise fail.
If we fail due to a size-mismatch, we return -E2BIG and write the kernel's
native attribe size back into the provided structure.
Furthermore, add some attribute verification, so that we'll fail counter
creation when unknown bits are present (PERF_SAMPLE, PERF_FORMAT, or in
the __reserved fields).
(This ABI detail is introduced while keeping the existing syscall ABI.)
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/perf/perf.h | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/tools/perf/perf.h b/tools/perf/perf.h index af0a5046d743..87a1aca4a424 100644 --- a/tools/perf/perf.h +++ b/tools/perf/perf.h @@ -53,11 +53,12 @@ static inline unsigned long long rdclock(void) _min1 < _min2 ? _min1 : _min2; }) static inline int -sys_perf_counter_open(struct perf_counter_attr *attr_uptr, +sys_perf_counter_open(struct perf_counter_attr *attr, pid_t pid, int cpu, int group_fd, unsigned long flags) { - return syscall(__NR_perf_counter_open, attr_uptr, pid, cpu, + attr->size = sizeof(*attr); + return syscall(__NR_perf_counter_open, attr, pid, cpu, group_fd, flags); } |