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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/syscalls.h | |
| parent | bbd36e5e6aa6f1757c84cdb406b6eb81686d14af (diff) | |
| download | lwn-974802eaa1afdc87e00821df7020a2b3c6fee623.tar.gz lwn-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/syscalls.h')
| -rw-r--r-- | include/linux/syscalls.h | 2 |
1 files changed, 1 insertions, 1 deletions
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 |