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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2009-06-12 12:46:55 +0200
committerIngo Molnar <mingo@elte.hu>2009-06-12 14:28:52 +0200
commit974802eaa1afdc87e00821df7020a2b3c6fee623 (patch)
treeb5c38bece7f4948fe9d5cf9be02a0042e0fa39f6 /include
parentbbd36e5e6aa6f1757c84cdb406b6eb81686d14af (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 'include')
-rw-r--r--include/linux/perf_counter.h19
-rw-r--r--include/linux/syscalls.h2
2 files changed, 16 insertions, 5 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;
};
/*
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index c6c84ad8bd71..418d90f5effe 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -758,6 +758,6 @@ int kernel_execve(const char *filename, char *const argv[], char *const envp[]);
asmlinkage long sys_perf_counter_open(
- const struct perf_counter_attr __user *attr_uptr,
+ struct perf_counter_attr __user *attr_uptr,
pid_t pid, int cpu, int group_fd, unsigned long flags);
#endif