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https://github.com/torvalds/linux
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718c602d67
This patch supports the addition to the kernel of AUX area buffers that can be mmapped separately from the perf-events buffer. The AUX buffer can be configured to contain hardware-produced trace information. The first implementation will support Intel BTS and Intel PT. One auxtrace buffer is mmapped per perf-events buffer. If the requested auxtrace buffer size is zero, which it will be until further support is added, then no auxtrace mmapping is attempted. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/r/1428594864-29309-3-git-send-email-adrian.hunter@intel.com [ Fixed conflict in evlist.h ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
114 lines
2.6 KiB
C
114 lines
2.6 KiB
C
/*
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* auxtrace.c: AUX area trace support
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* Copyright (c) 2013-2015, Intel Corporation.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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*/
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <stdbool.h>
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#include <linux/kernel.h>
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#include <linux/perf_event.h>
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#include <linux/types.h>
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#include <linux/bitops.h>
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#include <linux/log2.h>
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#include "../perf.h"
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#include "util.h"
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#include "evlist.h"
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#include "cpumap.h"
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#include "thread_map.h"
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#include "asm/bug.h"
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#include "auxtrace.h"
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int auxtrace_mmap__mmap(struct auxtrace_mmap *mm,
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struct auxtrace_mmap_params *mp,
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void *userpg, int fd)
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{
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struct perf_event_mmap_page *pc = userpg;
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#if BITS_PER_LONG != 64 && !defined(HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT)
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pr_err("Cannot use AUX area tracing mmaps\n");
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return -1;
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#endif
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WARN_ONCE(mm->base, "Uninitialized auxtrace_mmap\n");
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mm->userpg = userpg;
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mm->mask = mp->mask;
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mm->len = mp->len;
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mm->prev = 0;
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mm->idx = mp->idx;
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mm->tid = mp->tid;
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mm->cpu = mp->cpu;
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if (!mp->len) {
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mm->base = NULL;
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return 0;
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}
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pc->aux_offset = mp->offset;
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pc->aux_size = mp->len;
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mm->base = mmap(NULL, mp->len, mp->prot, MAP_SHARED, fd, mp->offset);
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if (mm->base == MAP_FAILED) {
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pr_debug2("failed to mmap AUX area\n");
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mm->base = NULL;
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return -1;
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}
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return 0;
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}
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void auxtrace_mmap__munmap(struct auxtrace_mmap *mm)
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{
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if (mm->base) {
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munmap(mm->base, mm->len);
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mm->base = NULL;
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}
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}
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void auxtrace_mmap_params__init(struct auxtrace_mmap_params *mp,
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off_t auxtrace_offset,
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unsigned int auxtrace_pages,
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bool auxtrace_overwrite)
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{
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if (auxtrace_pages) {
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mp->offset = auxtrace_offset;
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mp->len = auxtrace_pages * (size_t)page_size;
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mp->mask = is_power_of_2(mp->len) ? mp->len - 1 : 0;
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mp->prot = PROT_READ | (auxtrace_overwrite ? 0 : PROT_WRITE);
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pr_debug2("AUX area mmap length %zu\n", mp->len);
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} else {
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mp->len = 0;
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}
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}
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void auxtrace_mmap_params__set_idx(struct auxtrace_mmap_params *mp,
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struct perf_evlist *evlist, int idx,
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bool per_cpu)
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{
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mp->idx = idx;
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if (per_cpu) {
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mp->cpu = evlist->cpus->map[idx];
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if (evlist->threads)
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mp->tid = evlist->threads->map[0];
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else
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mp->tid = -1;
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} else {
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mp->cpu = -1;
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mp->tid = evlist->threads->map[idx];
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}
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}
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