diff options
Diffstat (limited to 'arch/x86/kernel/cpu/perf_event_intel_bts.c')
| -rw-r--r-- | arch/x86/kernel/cpu/perf_event_intel_bts.c | 544 |
1 files changed, 0 insertions, 544 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_intel_bts.c b/arch/x86/kernel/cpu/perf_event_intel_bts.c deleted file mode 100644 index 2cad71d1b14c..000000000000 --- a/arch/x86/kernel/cpu/perf_event_intel_bts.c +++ /dev/null @@ -1,544 +0,0 @@ -/* - * BTS PMU driver for perf - * Copyright (c) 2013-2014, Intel Corporation. - * - * This program is free software; you can redistribute it and/or modify it - * under the terms and conditions of the GNU General Public License, - * version 2, as published by the Free Software Foundation. - * - * This program is distributed in the hope it will be useful, but WITHOUT - * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or - * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for - * more details. - */ - -#undef DEBUG - -#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt - -#include <linux/bitops.h> -#include <linux/types.h> -#include <linux/slab.h> -#include <linux/debugfs.h> -#include <linux/device.h> -#include <linux/coredump.h> - -#include <asm-generic/sizes.h> -#include <asm/perf_event.h> - -#include "perf_event.h" - -struct bts_ctx { - struct perf_output_handle handle; - struct debug_store ds_back; - int started; -}; - -static DEFINE_PER_CPU(struct bts_ctx, bts_ctx); - -#define BTS_RECORD_SIZE 24 -#define BTS_SAFETY_MARGIN 4080 - -struct bts_phys { - struct page *page; - unsigned long size; - unsigned long offset; - unsigned long displacement; -}; - -struct bts_buffer { - size_t real_size; /* multiple of BTS_RECORD_SIZE */ - unsigned int nr_pages; - unsigned int nr_bufs; - unsigned int cur_buf; - bool snapshot; - local_t data_size; - local_t lost; - local_t head; - unsigned long end; - void **data_pages; - struct bts_phys buf[0]; -}; - -struct pmu bts_pmu; - -static size_t buf_size(struct page *page) -{ - return 1 << (PAGE_SHIFT + page_private(page)); -} - -static void * -bts_buffer_setup_aux(int cpu, void **pages, int nr_pages, bool overwrite) -{ - struct bts_buffer *buf; - struct page *page; - int node = (cpu == -1) ? cpu : cpu_to_node(cpu); - unsigned long offset; - size_t size = nr_pages << PAGE_SHIFT; - int pg, nbuf, pad; - - /* count all the high order buffers */ - for (pg = 0, nbuf = 0; pg < nr_pages;) { - page = virt_to_page(pages[pg]); - if (WARN_ON_ONCE(!PagePrivate(page) && nr_pages > 1)) - return NULL; - pg += 1 << page_private(page); - nbuf++; - } - - /* - * to avoid interrupts in overwrite mode, only allow one physical - */ - if (overwrite && nbuf > 1) - return NULL; - - buf = kzalloc_node(offsetof(struct bts_buffer, buf[nbuf]), GFP_KERNEL, node); - if (!buf) - return NULL; - - buf->nr_pages = nr_pages; - buf->nr_bufs = nbuf; - buf->snapshot = overwrite; - buf->data_pages = pages; - buf->real_size = size - size % BTS_RECORD_SIZE; - - for (pg = 0, nbuf = 0, offset = 0, pad = 0; nbuf < buf->nr_bufs; nbuf++) { - unsigned int __nr_pages; - - page = virt_to_page(pages[pg]); - __nr_pages = PagePrivate(page) ? 1 << page_private(page) : 1; - buf->buf[nbuf].page = page; - buf->buf[nbuf].offset = offset; - buf->buf[nbuf].displacement = (pad ? BTS_RECORD_SIZE - pad : 0); - buf->buf[nbuf].size = buf_size(page) - buf->buf[nbuf].displacement; - pad = buf->buf[nbuf].size % BTS_RECORD_SIZE; - buf->buf[nbuf].size -= pad; - - pg += __nr_pages; - offset += __nr_pages << PAGE_SHIFT; - } - - return buf; -} - -static void bts_buffer_free_aux(void *data) -{ - kfree(data); -} - -static unsigned long bts_buffer_offset(struct bts_buffer *buf, unsigned int idx) -{ - return buf->buf[idx].offset + buf->buf[idx].displacement; -} - -static void -bts_config_buffer(struct bts_buffer *buf) -{ - int cpu = raw_smp_processor_id(); - struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds; - struct bts_phys *phys = &buf->buf[buf->cur_buf]; - unsigned long index, thresh = 0, end = phys->size; - struct page *page = phys->page; - - index = local_read(&buf->head); - - if (!buf->snapshot) { - if (buf->end < phys->offset + buf_size(page)) - end = buf->end - phys->offset - phys->displacement; - - index -= phys->offset + phys->displacement; - - if (end - index > BTS_SAFETY_MARGIN) - thresh = end - BTS_SAFETY_MARGIN; - else if (end - index > BTS_RECORD_SIZE) - thresh = end - BTS_RECORD_SIZE; - else - thresh = end; - } - - ds->bts_buffer_base = (u64)(long)page_address(page) + phys->displacement; - ds->bts_index = ds->bts_buffer_base + index; - ds->bts_absolute_maximum = ds->bts_buffer_base + end; - ds->bts_interrupt_threshold = !buf->snapshot - ? ds->bts_buffer_base + thresh - : ds->bts_absolute_maximum + BTS_RECORD_SIZE; -} - -static void bts_buffer_pad_out(struct bts_phys *phys, unsigned long head) -{ - unsigned long index = head - phys->offset; - - memset(page_address(phys->page) + index, 0, phys->size - index); -} - -static bool bts_buffer_is_full(struct bts_buffer *buf, struct bts_ctx *bts) -{ - if (buf->snapshot) - return false; - - if (local_read(&buf->data_size) >= bts->handle.size || - bts->handle.size - local_read(&buf->data_size) < BTS_RECORD_SIZE) - return true; - - return false; -} - -static void bts_update(struct bts_ctx *bts) -{ - int cpu = raw_smp_processor_id(); - struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds; - struct bts_buffer *buf = perf_get_aux(&bts->handle); - unsigned long index = ds->bts_index - ds->bts_buffer_base, old, head; - - if (!buf) - return; - - head = index + bts_buffer_offset(buf, buf->cur_buf); - old = local_xchg(&buf->head, head); - - if (!buf->snapshot) { - if (old == head) - return; - - if (ds->bts_index >= ds->bts_absolute_maximum) - local_inc(&buf->lost); - - /* - * old and head are always in the same physical buffer, so we - * can subtract them to get the data size. - */ - local_add(head - old, &buf->data_size); - } else { - local_set(&buf->data_size, head); - } -} - -static void __bts_event_start(struct perf_event *event) -{ - struct bts_ctx *bts = this_cpu_ptr(&bts_ctx); - struct bts_buffer *buf = perf_get_aux(&bts->handle); - u64 config = 0; - - if (!buf || bts_buffer_is_full(buf, bts)) - return; - - event->hw.itrace_started = 1; - event->hw.state = 0; - - if (!buf->snapshot) - config |= ARCH_PERFMON_EVENTSEL_INT; - if (!event->attr.exclude_kernel) - config |= ARCH_PERFMON_EVENTSEL_OS; - if (!event->attr.exclude_user) - config |= ARCH_PERFMON_EVENTSEL_USR; - - bts_config_buffer(buf); - - /* - * local barrier to make sure that ds configuration made it - * before we enable BTS - */ - wmb(); - - intel_pmu_enable_bts(config); -} - -static void bts_event_start(struct perf_event *event, int flags) -{ - struct bts_ctx *bts = this_cpu_ptr(&bts_ctx); - - __bts_event_start(event); - - /* PMI handler: this counter is running and likely generating PMIs */ - ACCESS_ONCE(bts->started) = 1; -} - -static void __bts_event_stop(struct perf_event *event) -{ - /* - * No extra synchronization is mandated by the documentation to have - * BTS data stores globally visible. - */ - intel_pmu_disable_bts(); - - if (event->hw.state & PERF_HES_STOPPED) - return; - - ACCESS_ONCE(event->hw.state) |= PERF_HES_STOPPED; -} - -static void bts_event_stop(struct perf_event *event, int flags) -{ - struct bts_ctx *bts = this_cpu_ptr(&bts_ctx); - - /* PMI handler: don't restart this counter */ - ACCESS_ONCE(bts->started) = 0; - - __bts_event_stop(event); - - if (flags & PERF_EF_UPDATE) - bts_update(bts); -} - -void intel_bts_enable_local(void) -{ - struct bts_ctx *bts = this_cpu_ptr(&bts_ctx); - - if (bts->handle.event && bts->started) - __bts_event_start(bts->handle.event); -} - -void intel_bts_disable_local(void) -{ - struct bts_ctx *bts = this_cpu_ptr(&bts_ctx); - - if (bts->handle.event) - __bts_event_stop(bts->handle.event); -} - -static int -bts_buffer_reset(struct bts_buffer *buf, struct perf_output_handle *handle) -{ - unsigned long head, space, next_space, pad, gap, skip, wakeup; - unsigned int next_buf; - struct bts_phys *phys, *next_phys; - int ret; - - if (buf->snapshot) - return 0; - - head = handle->head & ((buf->nr_pages << PAGE_SHIFT) - 1); - if (WARN_ON_ONCE(head != local_read(&buf->head))) - return -EINVAL; - - phys = &buf->buf[buf->cur_buf]; - space = phys->offset + phys->displacement + phys->size - head; - pad = space; - if (space > handle->size) { - space = handle->size; - space -= space % BTS_RECORD_SIZE; - } - if (space <= BTS_SAFETY_MARGIN) { - /* See if next phys buffer has more space */ - next_buf = buf->cur_buf + 1; - if (next_buf >= buf->nr_bufs) - next_buf = 0; - next_phys = &buf->buf[next_buf]; - gap = buf_size(phys->page) - phys->displacement - phys->size + - next_phys->displacement; - skip = pad + gap; - if (handle->size >= skip) { - next_space = next_phys->size; - if (next_space + skip > handle->size) { - next_space = handle->size - skip; - next_space -= next_space % BTS_RECORD_SIZE; - } - if (next_space > space || !space) { - if (pad) - bts_buffer_pad_out(phys, head); - ret = perf_aux_output_skip(handle, skip); - if (ret) - return ret; - /* Advance to next phys buffer */ - phys = next_phys; - space = next_space; - head = phys->offset + phys->displacement; - /* - * After this, cur_buf and head won't match ds - * anymore, so we must not be racing with - * bts_update(). - */ - buf->cur_buf = next_buf; - local_set(&buf->head, head); - } - } - } - - /* Don't go far beyond wakeup watermark */ - wakeup = BTS_SAFETY_MARGIN + BTS_RECORD_SIZE + handle->wakeup - - handle->head; - if (space > wakeup) { - space = wakeup; - space -= space % BTS_RECORD_SIZE; - } - - buf->end = head + space; - - /* - * If we have no space, the lost notification would have been sent when - * we hit absolute_maximum - see bts_update() - */ - if (!space) - return -ENOSPC; - - return 0; -} - -int intel_bts_interrupt(void) -{ - struct bts_ctx *bts = this_cpu_ptr(&bts_ctx); - struct perf_event *event = bts->handle.event; - struct bts_buffer *buf; - s64 old_head; - int err; - - if (!event || !bts->started) - return 0; - - buf = perf_get_aux(&bts->handle); - /* - * Skip snapshot counters: they don't use the interrupt, but - * there's no other way of telling, because the pointer will - * keep moving - */ - if (!buf || buf->snapshot) - return 0; - - old_head = local_read(&buf->head); - bts_update(bts); - - /* no new data */ - if (old_head == local_read(&buf->head)) - return 0; - - perf_aux_output_end(&bts->handle, local_xchg(&buf->data_size, 0), - !!local_xchg(&buf->lost, 0)); - - buf = perf_aux_output_begin(&bts->handle, event); - if (!buf) - return 1; - - err = bts_buffer_reset(buf, &bts->handle); - if (err) - perf_aux_output_end(&bts->handle, 0, false); - - return 1; -} - -static void bts_event_del(struct perf_event *event, int mode) -{ - struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); - struct bts_ctx *bts = this_cpu_ptr(&bts_ctx); - struct bts_buffer *buf = perf_get_aux(&bts->handle); - - bts_event_stop(event, PERF_EF_UPDATE); - - if (buf) { - if (buf->snapshot) - bts->handle.head = - local_xchg(&buf->data_size, - buf->nr_pages << PAGE_SHIFT); - perf_aux_output_end(&bts->handle, local_xchg(&buf->data_size, 0), - !!local_xchg(&buf->lost, 0)); - } - - cpuc->ds->bts_index = bts->ds_back.bts_buffer_base; - cpuc->ds->bts_buffer_base = bts->ds_back.bts_buffer_base; - cpuc->ds->bts_absolute_maximum = bts->ds_back.bts_absolute_maximum; - cpuc->ds->bts_interrupt_threshold = bts->ds_back.bts_interrupt_threshold; -} - -static int bts_event_add(struct perf_event *event, int mode) -{ - struct bts_buffer *buf; - struct bts_ctx *bts = this_cpu_ptr(&bts_ctx); - struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events); - struct hw_perf_event *hwc = &event->hw; - int ret = -EBUSY; - - event->hw.state = PERF_HES_STOPPED; - - if (test_bit(INTEL_PMC_IDX_FIXED_BTS, cpuc->active_mask)) - return -EBUSY; - - if (bts->handle.event) - return -EBUSY; - - buf = perf_aux_output_begin(&bts->handle, event); - if (!buf) - return -EINVAL; - - ret = bts_buffer_reset(buf, &bts->handle); - if (ret) { - perf_aux_output_end(&bts->handle, 0, false); - return ret; - } - - bts->ds_back.bts_buffer_base = cpuc->ds->bts_buffer_base; - bts->ds_back.bts_absolute_maximum = cpuc->ds->bts_absolute_maximum; - bts->ds_back.bts_interrupt_threshold = cpuc->ds->bts_interrupt_threshold; - - if (mode & PERF_EF_START) { - bts_event_start(event, 0); - if (hwc->state & PERF_HES_STOPPED) { - bts_event_del(event, 0); - return -EBUSY; - } - } - - return 0; -} - -static void bts_event_destroy(struct perf_event *event) -{ - x86_release_hardware(); - x86_del_exclusive(x86_lbr_exclusive_bts); -} - -static int bts_event_init(struct perf_event *event) -{ - int ret; - - if (event->attr.type != bts_pmu.type) - return -ENOENT; - - if (x86_add_exclusive(x86_lbr_exclusive_bts)) - return -EBUSY; - - /* - * BTS leaks kernel addresses even when CPL0 tracing is - * disabled, so disallow intel_bts driver for unprivileged - * users on paranoid systems since it provides trace data - * to the user in a zero-copy fashion. - * - * Note that the default paranoia setting permits unprivileged - * users to profile the kernel. - */ - if (event->attr.exclude_kernel && perf_paranoid_kernel() && - !capable(CAP_SYS_ADMIN)) - return -EACCES; - - ret = x86_reserve_hardware(); - if (ret) { - x86_del_exclusive(x86_lbr_exclusive_bts); - return ret; - } - - event->destroy = bts_event_destroy; - - return 0; -} - -static void bts_event_read(struct perf_event *event) -{ -} - -static __init int bts_init(void) -{ - if (!boot_cpu_has(X86_FEATURE_DTES64) || !x86_pmu.bts) - return -ENODEV; - - bts_pmu.capabilities = PERF_PMU_CAP_AUX_NO_SG | PERF_PMU_CAP_ITRACE; - bts_pmu.task_ctx_nr = perf_sw_context; - bts_pmu.event_init = bts_event_init; - bts_pmu.add = bts_event_add; - bts_pmu.del = bts_event_del; - bts_pmu.start = bts_event_start; - bts_pmu.stop = bts_event_stop; - bts_pmu.read = bts_event_read; - bts_pmu.setup_aux = bts_buffer_setup_aux; - bts_pmu.free_aux = bts_buffer_free_aux; - - return perf_pmu_register(&bts_pmu, "intel_bts", -1); -} -arch_initcall(bts_init); |