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![Peter Zijlstra](/assets/img/avatar_default.png)
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>
68 lines
1.6 KiB
C
68 lines
1.6 KiB
C
#ifndef _PERF_PERF_H
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#define _PERF_PERF_H
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#if defined(__x86_64__) || defined(__i386__)
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#include "../../arch/x86/include/asm/unistd.h"
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#define rmb() asm volatile("lfence" ::: "memory")
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#define cpu_relax() asm volatile("rep; nop" ::: "memory");
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#endif
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#ifdef __powerpc__
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#include "../../arch/powerpc/include/asm/unistd.h"
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#define rmb() asm volatile ("sync" ::: "memory")
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#define cpu_relax() asm volatile ("" ::: "memory");
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#endif
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#include <time.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/syscall.h>
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#include "../../include/linux/perf_counter.h"
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/*
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* prctl(PR_TASK_PERF_COUNTERS_DISABLE) will (cheaply) disable all
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* counters in the current task.
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*/
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#define PR_TASK_PERF_COUNTERS_DISABLE 31
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#define PR_TASK_PERF_COUNTERS_ENABLE 32
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#ifndef NSEC_PER_SEC
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# define NSEC_PER_SEC 1000000000ULL
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#endif
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static inline unsigned long long rdclock(void)
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{
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struct timespec ts;
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clock_gettime(CLOCK_MONOTONIC, &ts);
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return ts.tv_sec * 1000000000ULL + ts.tv_nsec;
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}
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/*
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* Pick up some kernel type conventions:
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*/
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#define __user
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#define asmlinkage
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#define unlikely(x) __builtin_expect(!!(x), 0)
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#define min(x, y) ({ \
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typeof(x) _min1 = (x); \
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typeof(y) _min2 = (y); \
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(void) (&_min1 == &_min2); \
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_min1 < _min2 ? _min1 : _min2; })
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static inline int
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sys_perf_counter_open(struct perf_counter_attr *attr,
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pid_t pid, int cpu, int group_fd,
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unsigned long flags)
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{
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attr->size = sizeof(*attr);
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return syscall(__NR_perf_counter_open, attr, pid, cpu,
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group_fd, flags);
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}
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#define MAX_COUNTERS 256
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#define MAX_NR_CPUS 256
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#endif
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