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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2009-06-12 12:46:55 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-06-12 14:28:52 +0200 |
| commit | 974802eaa1afdc87e00821df7020a2b3c6fee623 (patch) | |
| tree | b5c38bece7f4948fe9d5cf9be02a0042e0fa39f6 /include/linux/perf_counter.h | |
| parent | bbd36e5e6aa6f1757c84cdb406b6eb81686d14af (diff) | |
| download | linux-974802eaa1afdc87e00821df7020a2b3c6fee623.tar.gz linux-974802eaa1afdc87e00821df7020a2b3c6fee623.tar.bz2 linux-974802eaa1afdc87e00821df7020a2b3c6fee623.zip | |
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 'include/linux/perf_counter.h')
| -rw-r--r-- | include/linux/perf_counter.h | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h index 7c4f32f6ae1a..1b3118a1023a 100644 --- a/include/linux/perf_counter.h +++ b/include/linux/perf_counter.h @@ -120,6 +120,8 @@ enum perf_counter_sample_format { PERF_SAMPLE_ID = 1U << 6, PERF_SAMPLE_CPU = 1U << 7, PERF_SAMPLE_PERIOD = 1U << 8, + + PERF_SAMPLE_MAX = 1U << 9, /* non-ABI */ }; /* @@ -131,17 +133,26 @@ enum perf_counter_read_format { PERF_FORMAT_TOTAL_TIME_ENABLED = 1U << 0, PERF_FORMAT_TOTAL_TIME_RUNNING = 1U << 1, PERF_FORMAT_ID = 1U << 2, + + PERF_FORMAT_MAX = 1U << 3, /* non-ABI */ }; +#define PERF_ATTR_SIZE_VER0 64 /* sizeof first published struct */ + /* * Hardware event to monitor via a performance monitoring counter: */ struct perf_counter_attr { + /* * Major type: hardware/software/tracepoint/etc. */ __u32 type; - __u32 __reserved_1; + + /* + * Size of the attr structure, for fwd/bwd compat. + */ + __u32 size; /* * Type specific configuration information. @@ -168,12 +179,12 @@ struct perf_counter_attr { comm : 1, /* include comm data */ freq : 1, /* use freq, not period */ - __reserved_2 : 53; + __reserved_1 : 53; __u32 wakeup_events; /* wakeup every n events */ - __u32 __reserved_3; + __u32 __reserved_2; - __u64 __reserved_4; + __u64 __reserved_3; }; /* |