diff options
Diffstat (limited to 'arch/x86/kernel/cpu/perf_event_intel_pt.c')
| -rw-r--r-- | arch/x86/kernel/cpu/perf_event_intel_pt.c | 1188 |
1 files changed, 0 insertions, 1188 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_intel_pt.c b/arch/x86/kernel/cpu/perf_event_intel_pt.c deleted file mode 100644 index c0bbd1033b7c..000000000000 --- a/arch/x86/kernel/cpu/perf_event_intel_pt.c +++ /dev/null @@ -1,1188 +0,0 @@ -/* - * Intel(R) Processor Trace 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. - * - * Intel PT is specified in the Intel Architecture Instruction Set Extensions - * Programming Reference: - * http://software.intel.com/en-us/intel-isa-extensions - */ - -#undef DEBUG - -#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt - -#include <linux/types.h> -#include <linux/slab.h> -#include <linux/device.h> - -#include <asm/perf_event.h> -#include <asm/insn.h> -#include <asm/io.h> -#include <asm/intel_pt.h> - -#include "perf_event.h" -#include "intel_pt.h" - -static DEFINE_PER_CPU(struct pt, pt_ctx); - -static struct pt_pmu pt_pmu; - -enum cpuid_regs { - CR_EAX = 0, - CR_ECX, - CR_EDX, - CR_EBX -}; - -/* - * Capabilities of Intel PT hardware, such as number of address bits or - * supported output schemes, are cached and exported to userspace as "caps" - * attribute group of pt pmu device - * (/sys/bus/event_source/devices/intel_pt/caps/) so that userspace can store - * relevant bits together with intel_pt traces. - * - * These are necessary for both trace decoding (payloads_lip, contains address - * width encoded in IP-related packets), and event configuration (bitmasks with - * permitted values for certain bit fields). - */ -#define PT_CAP(_n, _l, _r, _m) \ - [PT_CAP_ ## _n] = { .name = __stringify(_n), .leaf = _l, \ - .reg = _r, .mask = _m } - -static struct pt_cap_desc { - const char *name; - u32 leaf; - u8 reg; - u32 mask; -} pt_caps[] = { - PT_CAP(max_subleaf, 0, CR_EAX, 0xffffffff), - PT_CAP(cr3_filtering, 0, CR_EBX, BIT(0)), - PT_CAP(psb_cyc, 0, CR_EBX, BIT(1)), - PT_CAP(mtc, 0, CR_EBX, BIT(3)), - PT_CAP(topa_output, 0, CR_ECX, BIT(0)), - PT_CAP(topa_multiple_entries, 0, CR_ECX, BIT(1)), - PT_CAP(single_range_output, 0, CR_ECX, BIT(2)), - PT_CAP(payloads_lip, 0, CR_ECX, BIT(31)), - PT_CAP(mtc_periods, 1, CR_EAX, 0xffff0000), - PT_CAP(cycle_thresholds, 1, CR_EBX, 0xffff), - PT_CAP(psb_periods, 1, CR_EBX, 0xffff0000), -}; - -static u32 pt_cap_get(enum pt_capabilities cap) -{ - struct pt_cap_desc *cd = &pt_caps[cap]; - u32 c = pt_pmu.caps[cd->leaf * PT_CPUID_REGS_NUM + cd->reg]; - unsigned int shift = __ffs(cd->mask); - - return (c & cd->mask) >> shift; -} - -static ssize_t pt_cap_show(struct device *cdev, - struct device_attribute *attr, - char *buf) -{ - struct dev_ext_attribute *ea = - container_of(attr, struct dev_ext_attribute, attr); - enum pt_capabilities cap = (long)ea->var; - - return snprintf(buf, PAGE_SIZE, "%x\n", pt_cap_get(cap)); -} - -static struct attribute_group pt_cap_group = { - .name = "caps", -}; - -PMU_FORMAT_ATTR(cyc, "config:1" ); -PMU_FORMAT_ATTR(mtc, "config:9" ); -PMU_FORMAT_ATTR(tsc, "config:10" ); -PMU_FORMAT_ATTR(noretcomp, "config:11" ); -PMU_FORMAT_ATTR(mtc_period, "config:14-17" ); -PMU_FORMAT_ATTR(cyc_thresh, "config:19-22" ); -PMU_FORMAT_ATTR(psb_period, "config:24-27" ); - -static struct attribute *pt_formats_attr[] = { - &format_attr_cyc.attr, - &format_attr_mtc.attr, - &format_attr_tsc.attr, - &format_attr_noretcomp.attr, - &format_attr_mtc_period.attr, - &format_attr_cyc_thresh.attr, - &format_attr_psb_period.attr, - NULL, -}; - -static struct attribute_group pt_format_group = { - .name = "format", - .attrs = pt_formats_attr, -}; - -static const struct attribute_group *pt_attr_groups[] = { - &pt_cap_group, - &pt_format_group, - NULL, -}; - -static int __init pt_pmu_hw_init(void) -{ - struct dev_ext_attribute *de_attrs; - struct attribute **attrs; - size_t size; - int ret; - long i; - - attrs = NULL; - - for (i = 0; i < PT_CPUID_LEAVES; i++) { - cpuid_count(20, i, - &pt_pmu.caps[CR_EAX + i*PT_CPUID_REGS_NUM], - &pt_pmu.caps[CR_EBX + i*PT_CPUID_REGS_NUM], - &pt_pmu.caps[CR_ECX + i*PT_CPUID_REGS_NUM], - &pt_pmu.caps[CR_EDX + i*PT_CPUID_REGS_NUM]); - } - - ret = -ENOMEM; - size = sizeof(struct attribute *) * (ARRAY_SIZE(pt_caps)+1); - attrs = kzalloc(size, GFP_KERNEL); - if (!attrs) - goto fail; - - size = sizeof(struct dev_ext_attribute) * (ARRAY_SIZE(pt_caps)+1); - de_attrs = kzalloc(size, GFP_KERNEL); - if (!de_attrs) - goto fail; - - for (i = 0; i < ARRAY_SIZE(pt_caps); i++) { - struct dev_ext_attribute *de_attr = de_attrs + i; - - de_attr->attr.attr.name = pt_caps[i].name; - - sysfs_attr_init(&de_attr->attr.attr); - - de_attr->attr.attr.mode = S_IRUGO; - de_attr->attr.show = pt_cap_show; - de_attr->var = (void *)i; - - attrs[i] = &de_attr->attr.attr; - } - - pt_cap_group.attrs = attrs; - - return 0; - -fail: - kfree(attrs); - - return ret; -} - -#define RTIT_CTL_CYC_PSB (RTIT_CTL_CYCLEACC | \ - RTIT_CTL_CYC_THRESH | \ - RTIT_CTL_PSB_FREQ) - -#define RTIT_CTL_MTC (RTIT_CTL_MTC_EN | \ - RTIT_CTL_MTC_RANGE) - -#define PT_CONFIG_MASK (RTIT_CTL_TSC_EN | \ - RTIT_CTL_DISRETC | \ - RTIT_CTL_CYC_PSB | \ - RTIT_CTL_MTC) - -static bool pt_event_valid(struct perf_event *event) -{ - u64 config = event->attr.config; - u64 allowed, requested; - - if ((config & PT_CONFIG_MASK) != config) - return false; - - if (config & RTIT_CTL_CYC_PSB) { - if (!pt_cap_get(PT_CAP_psb_cyc)) - return false; - - allowed = pt_cap_get(PT_CAP_psb_periods); - requested = (config & RTIT_CTL_PSB_FREQ) >> - RTIT_CTL_PSB_FREQ_OFFSET; - if (requested && (!(allowed & BIT(requested)))) - return false; - - allowed = pt_cap_get(PT_CAP_cycle_thresholds); - requested = (config & RTIT_CTL_CYC_THRESH) >> - RTIT_CTL_CYC_THRESH_OFFSET; - if (requested && (!(allowed & BIT(requested)))) - return false; - } - - if (config & RTIT_CTL_MTC) { - /* - * In the unlikely case that CPUID lists valid mtc periods, - * but not the mtc capability, drop out here. - * - * Spec says that setting mtc period bits while mtc bit in - * CPUID is 0 will #GP, so better safe than sorry. - */ - if (!pt_cap_get(PT_CAP_mtc)) - return false; - - allowed = pt_cap_get(PT_CAP_mtc_periods); - if (!allowed) - return false; - - requested = (config & RTIT_CTL_MTC_RANGE) >> - RTIT_CTL_MTC_RANGE_OFFSET; - - if (!(allowed & BIT(requested))) - return false; - } - - return true; -} - -/* - * PT configuration helpers - * These all are cpu affine and operate on a local PT - */ - -static void pt_config(struct perf_event *event) -{ - u64 reg; - - if (!event->hw.itrace_started) { - event->hw.itrace_started = 1; - wrmsrl(MSR_IA32_RTIT_STATUS, 0); - } - - reg = RTIT_CTL_TOPA | RTIT_CTL_BRANCH_EN | RTIT_CTL_TRACEEN; - - if (!event->attr.exclude_kernel) - reg |= RTIT_CTL_OS; - if (!event->attr.exclude_user) - reg |= RTIT_CTL_USR; - - reg |= (event->attr.config & PT_CONFIG_MASK); - - wrmsrl(MSR_IA32_RTIT_CTL, reg); -} - -static void pt_config_start(bool start) -{ - u64 ctl; - - rdmsrl(MSR_IA32_RTIT_CTL, ctl); - if (start) - ctl |= RTIT_CTL_TRACEEN; - else - ctl &= ~RTIT_CTL_TRACEEN; - wrmsrl(MSR_IA32_RTIT_CTL, ctl); - - /* - * A wrmsr that disables trace generation serializes other PT - * registers and causes all data packets to be written to memory, - * but a fence is required for the data to become globally visible. - * - * The below WMB, separating data store and aux_head store matches - * the consumer's RMB that separates aux_head load and data load. - */ - if (!start) - wmb(); -} - -static void pt_config_buffer(void *buf, unsigned int topa_idx, - unsigned int output_off) -{ - u64 reg; - - wrmsrl(MSR_IA32_RTIT_OUTPUT_BASE, virt_to_phys(buf)); - - reg = 0x7f | ((u64)topa_idx << 7) | ((u64)output_off << 32); - - wrmsrl(MSR_IA32_RTIT_OUTPUT_MASK, reg); -} - -/* - * Keep ToPA table-related metadata on the same page as the actual table, - * taking up a few words from the top - */ - -#define TENTS_PER_PAGE (((PAGE_SIZE - 40) / sizeof(struct topa_entry)) - 1) - -/** - * struct topa - page-sized ToPA table with metadata at the top - * @table: actual ToPA table entries, as understood by PT hardware - * @list: linkage to struct pt_buffer's list of tables - * @phys: physical address of this page - * @offset: offset of the first entry in this table in the buffer - * @size: total size of all entries in this table - * @last: index of the last initialized entry in this table - */ -struct topa { - struct topa_entry table[TENTS_PER_PAGE]; - struct list_head list; - u64 phys; - u64 offset; - size_t size; - int last; -}; - -/* make -1 stand for the last table entry */ -#define TOPA_ENTRY(t, i) ((i) == -1 ? &(t)->table[(t)->last] : &(t)->table[(i)]) - -/** - * topa_alloc() - allocate page-sized ToPA table - * @cpu: CPU on which to allocate. - * @gfp: Allocation flags. - * - * Return: On success, return the pointer to ToPA table page. - */ -static struct topa *topa_alloc(int cpu, gfp_t gfp) -{ - int node = cpu_to_node(cpu); - struct topa *topa; - struct page *p; - - p = alloc_pages_node(node, gfp | __GFP_ZERO, 0); - if (!p) - return NULL; - - topa = page_address(p); - topa->last = 0; - topa->phys = page_to_phys(p); - - /* - * In case of singe-entry ToPA, always put the self-referencing END - * link as the 2nd entry in the table - */ - if (!pt_cap_get(PT_CAP_topa_multiple_entries)) { - TOPA_ENTRY(topa, 1)->base = topa->phys >> TOPA_SHIFT; - TOPA_ENTRY(topa, 1)->end = 1; - } - - return topa; -} - -/** - * topa_free() - free a page-sized ToPA table - * @topa: Table to deallocate. - */ -static void topa_free(struct topa *topa) -{ - free_page((unsigned long)topa); -} - -/** - * topa_insert_table() - insert a ToPA table into a buffer - * @buf: PT buffer that's being extended. - * @topa: New topa table to be inserted. - * - * If it's the first table in this buffer, set up buffer's pointers - * accordingly; otherwise, add a END=1 link entry to @topa to the current - * "last" table and adjust the last table pointer to @topa. - */ -static void topa_insert_table(struct pt_buffer *buf, struct topa *topa) -{ - struct topa *last = buf->last; - - list_add_tail(&topa->list, &buf->tables); - - if (!buf->first) { - buf->first = buf->last = buf->cur = topa; - return; - } - - topa->offset = last->offset + last->size; - buf->last = topa; - - if (!pt_cap_get(PT_CAP_topa_multiple_entries)) - return; - - BUG_ON(last->last != TENTS_PER_PAGE - 1); - - TOPA_ENTRY(last, -1)->base = topa->phys >> TOPA_SHIFT; - TOPA_ENTRY(last, -1)->end = 1; -} - -/** - * topa_table_full() - check if a ToPA table is filled up - * @topa: ToPA table. - */ -static bool topa_table_full(struct topa *topa) -{ - /* single-entry ToPA is a special case */ - if (!pt_cap_get(PT_CAP_topa_multiple_entries)) - return !!topa->last; - - return topa->last == TENTS_PER_PAGE - 1; -} - -/** - * topa_insert_pages() - create a list of ToPA tables - * @buf: PT buffer being initialized. - * @gfp: Allocation flags. - * - * This initializes a list of ToPA tables with entries from - * the data_pages provided by rb_alloc_aux(). - * - * Return: 0 on success or error code. - */ -static int topa_insert_pages(struct pt_buffer *buf, gfp_t gfp) -{ - struct topa *topa = buf->last; - int order = 0; - struct page *p; - - p = virt_to_page(buf->data_pages[buf->nr_pages]); - if (PagePrivate(p)) - order = page_private(p); - - if (topa_table_full(topa)) { - topa = topa_alloc(buf->cpu, gfp); - if (!topa) - return -ENOMEM; - - topa_insert_table(buf, topa); - } - - TOPA_ENTRY(topa, -1)->base = page_to_phys(p) >> TOPA_SHIFT; - TOPA_ENTRY(topa, -1)->size = order; - if (!buf->snapshot && !pt_cap_get(PT_CAP_topa_multiple_entries)) { - TOPA_ENTRY(topa, -1)->intr = 1; - TOPA_ENTRY(topa, -1)->stop = 1; - } - - topa->last++; - topa->size += sizes(order); - - buf->nr_pages += 1ul << order; - - return 0; -} - -/** - * pt_topa_dump() - print ToPA tables and their entries - * @buf: PT buffer. - */ -static void pt_topa_dump(struct pt_buffer *buf) -{ - struct topa *topa; - - list_for_each_entry(topa, &buf->tables, list) { - int i; - - pr_debug("# table @%p (%016Lx), off %llx size %zx\n", topa->table, - topa->phys, topa->offset, topa->size); - for (i = 0; i < TENTS_PER_PAGE; i++) { - pr_debug("# entry @%p (%lx sz %u %c%c%c) raw=%16llx\n", - &topa->table[i], - (unsigned long)topa->table[i].base << TOPA_SHIFT, - sizes(topa->table[i].size), - topa->table[i].end ? 'E' : ' ', - topa->table[i].intr ? 'I' : ' ', - topa->table[i].stop ? 'S' : ' ', - *(u64 *)&topa->table[i]); - if ((pt_cap_get(PT_CAP_topa_multiple_entries) && - topa->table[i].stop) || - topa->table[i].end) - break; - } - } -} - -/** - * pt_buffer_advance() - advance to the next output region - * @buf: PT buffer. - * - * Advance the current pointers in the buffer to the next ToPA entry. - */ -static void pt_buffer_advance(struct pt_buffer *buf) -{ - buf->output_off = 0; - buf->cur_idx++; - - if (buf->cur_idx == buf->cur->last) { - if (buf->cur == buf->last) - buf->cur = buf->first; - else - buf->cur = list_entry(buf->cur->list.next, struct topa, - list); - buf->cur_idx = 0; - } -} - -/** - * pt_update_head() - calculate current offsets and sizes - * @pt: Per-cpu pt context. - * - * Update buffer's current write pointer position and data size. - */ -static void pt_update_head(struct pt *pt) -{ - struct pt_buffer *buf = perf_get_aux(&pt->handle); - u64 topa_idx, base, old; - - /* offset of the first region in this table from the beginning of buf */ - base = buf->cur->offset + buf->output_off; - - /* offset of the current output region within this table */ - for (topa_idx = 0; topa_idx < buf->cur_idx; topa_idx++) - base += sizes(buf->cur->table[topa_idx].size); - - if (buf->snapshot) { - local_set(&buf->data_size, base); - } else { - old = (local64_xchg(&buf->head, base) & - ((buf->nr_pages << PAGE_SHIFT) - 1)); - if (base < old) - base += buf->nr_pages << PAGE_SHIFT; - - local_add(base - old, &buf->data_size); - } -} - -/** - * pt_buffer_region() - obtain current output region's address - * @buf: PT buffer. - */ -static void *pt_buffer_region(struct pt_buffer *buf) -{ - return phys_to_virt(buf->cur->table[buf->cur_idx].base << TOPA_SHIFT); -} - -/** - * pt_buffer_region_size() - obtain current output region's size - * @buf: PT buffer. - */ -static size_t pt_buffer_region_size(struct pt_buffer *buf) -{ - return sizes(buf->cur->table[buf->cur_idx].size); -} - -/** - * pt_handle_status() - take care of possible status conditions - * @pt: Per-cpu pt context. - */ -static void pt_handle_status(struct pt *pt) -{ - struct pt_buffer *buf = perf_get_aux(&pt->handle); - int advance = 0; - u64 status; - - rdmsrl(MSR_IA32_RTIT_STATUS, status); - - if (status & RTIT_STATUS_ERROR) { - pr_err_ratelimited("ToPA ERROR encountered, trying to recover\n"); - pt_topa_dump(buf); - status &= ~RTIT_STATUS_ERROR; - } - - if (status & RTIT_STATUS_STOPPED) { - status &= ~RTIT_STATUS_STOPPED; - - /* - * On systems that only do single-entry ToPA, hitting STOP - * means we are already losing data; need to let the decoder - * know. - */ - if (!pt_cap_get(PT_CAP_topa_multiple_entries) || - buf->output_off == sizes(TOPA_ENTRY(buf->cur, buf->cur_idx)->size)) { - local_inc(&buf->lost); - advance++; - } - } - - /* - * Also on single-entry ToPA implementations, interrupt will come - * before the output reaches its output region's boundary. - */ - if (!pt_cap_get(PT_CAP_topa_multiple_entries) && !buf->snapshot && - pt_buffer_region_size(buf) - buf->output_off <= TOPA_PMI_MARGIN) { - void *head = pt_buffer_region(buf); - - /* everything within this margin needs to be zeroed out */ - memset(head + buf->output_off, 0, - pt_buffer_region_size(buf) - - buf->output_off); - advance++; - } - - if (advance) - pt_buffer_advance(buf); - - wrmsrl(MSR_IA32_RTIT_STATUS, status); -} - -/** - * pt_read_offset() - translate registers into buffer pointers - * @buf: PT buffer. - * - * Set buffer's output pointers from MSR values. - */ -static void pt_read_offset(struct pt_buffer *buf) -{ - u64 offset, base_topa; - - rdmsrl(MSR_IA32_RTIT_OUTPUT_BASE, base_topa); - buf->cur = phys_to_virt(base_topa); - - rdmsrl(MSR_IA32_RTIT_OUTPUT_MASK, offset); - /* offset within current output region */ - buf->output_off = offset >> 32; - /* index of current output region within this table */ - buf->cur_idx = (offset & 0xffffff80) >> 7; -} - -/** - * pt_topa_next_entry() - obtain index of the first page in the next ToPA entry - * @buf: PT buffer. - * @pg: Page offset in the buffer. - * - * When advancing to the next output region (ToPA entry), given a page offset - * into the buffer, we need to find the offset of the first page in the next - * region. - */ -static unsigned int pt_topa_next_entry(struct pt_buffer *buf, unsigned int pg) -{ - struct topa_entry *te = buf->topa_index[pg]; - - /* one region */ - if (buf->first == buf->last && buf->first->last == 1) - return pg; - - do { - pg++; - pg &= buf->nr_pages - 1; - } while (buf->topa_index[pg] == te); - - return pg; -} - -/** - * pt_buffer_reset_markers() - place interrupt and stop bits in the buffer - * @buf: PT buffer. - * @handle: Current output handle. - * - * Place INT and STOP marks to prevent overwriting old data that the consumer - * hasn't yet collected and waking up the consumer after a certain fraction of - * the buffer has filled up. Only needed and sensible for non-snapshot counters. - * - * This obviously relies on buf::head to figure out buffer markers, so it has - * to be called after pt_buffer_reset_offsets() and before the hardware tracing - * is enabled. - */ -static int pt_buffer_reset_markers(struct pt_buffer *buf, - struct perf_output_handle *handle) - -{ - unsigned long head = local64_read(&buf->head); - unsigned long idx, npages, wakeup; - - /* can't stop in the middle of an output region */ - if (buf->output_off + handle->size + 1 < - sizes(TOPA_ENTRY(buf->cur, buf->cur_idx)->size)) - return -EINVAL; - - - /* single entry ToPA is handled by marking all regions STOP=1 INT=1 */ - if (!pt_cap_get(PT_CAP_topa_multiple_entries)) - return 0; - - /* clear STOP and INT from current entry */ - buf->topa_index[buf->stop_pos]->stop = 0; - buf->topa_index[buf->intr_pos]->intr = 0; - - /* how many pages till the STOP marker */ - npages = handle->size >> PAGE_SHIFT; - - /* if it's on a page boundary, fill up one more page */ - if (!offset_in_page(head + handle->size + 1)) - npages++; - - idx = (head >> PAGE_SHIFT) + npages; - idx &= buf->nr_pages - 1; - buf->stop_pos = idx; - - wakeup = handle->wakeup >> PAGE_SHIFT; - - /* in the worst case, wake up the consumer one page before hard stop */ - idx = (head >> PAGE_SHIFT) + npages - 1; - if (idx > wakeup) - idx = wakeup; - - idx &= buf->nr_pages - 1; - buf->intr_pos = idx; - - buf->topa_index[buf->stop_pos]->stop = 1; - buf->topa_index[buf->intr_pos]->intr = 1; - - return 0; -} - -/** - * pt_buffer_setup_topa_index() - build topa_index[] table of regions - * @buf: PT buffer. - * - * topa_index[] references output regions indexed by offset into the - * buffer for purposes of quick reverse lookup. - */ -static void pt_buffer_setup_topa_index(struct pt_buffer *buf) -{ - struct topa *cur = buf->first, *prev = buf->last; - struct topa_entry *te_cur = TOPA_ENTRY(cur, 0), - *te_prev = TOPA_ENTRY(prev, prev->last - 1); - int pg = 0, idx = 0; - - while (pg < buf->nr_pages) { - int tidx; - - /* pages within one topa entry */ - for (tidx = 0; tidx < 1 << te_cur->size; tidx++, pg++) - buf->topa_index[pg] = te_prev; - - te_prev = te_cur; - - if (idx == cur->last - 1) { - /* advance to next topa table */ - idx = 0; - cur = list_entry(cur->list.next, struct topa, list); - } else { - idx++; - } - te_cur = TOPA_ENTRY(cur, idx); - } - -} - -/** - * pt_buffer_reset_offsets() - adjust buffer's write pointers from aux_head - * @buf: PT buffer. - * @head: Write pointer (aux_head) from AUX buffer. - * - * Find the ToPA table and entry corresponding to given @head and set buffer's - * "current" pointers accordingly. This is done after we have obtained the - * current aux_head position from a successful call to perf_aux_output_begin() - * to make sure the hardware is writing to the right place. - * - * This function modifies buf::{cur,cur_idx,output_off} that will be programmed - * into PT msrs when the tracing is enabled and buf::head and buf::data_size, - * which are used to determine INT and STOP markers' locations by a subsequent - * call to pt_buffer_reset_markers(). - */ -static void pt_buffer_reset_offsets(struct pt_buffer *buf, unsigned long head) -{ - int pg; - - if (buf->snapshot) - head &= (buf->nr_pages << PAGE_SHIFT) - 1; - - pg = (head >> PAGE_SHIFT) & (buf->nr_pages - 1); - pg = pt_topa_next_entry(buf, pg); - - buf->cur = (struct topa *)((unsigned long)buf->topa_index[pg] & PAGE_MASK); - buf->cur_idx = ((unsigned long)buf->topa_index[pg] - - (unsigned long)buf->cur) / sizeof(struct topa_entry); - buf->output_off = head & (sizes(buf->cur->table[buf->cur_idx].size) - 1); - - local64_set(&buf->head, head); - local_set(&buf->data_size, 0); -} - -/** - * pt_buffer_fini_topa() - deallocate ToPA structure of a buffer - * @buf: PT buffer. - */ -static void pt_buffer_fini_topa(struct pt_buffer *buf) -{ - struct topa *topa, *iter; - - list_for_each_entry_safe(topa, iter, &buf->tables, list) { - /* - * right now, this is in free_aux() path only, so - * no need to unlink this table from the list - */ - topa_free(topa); - } -} - -/** - * pt_buffer_init_topa() - initialize ToPA table for pt buffer - * @buf: PT buffer. - * @size: Total size of all regions within this ToPA. - * @gfp: Allocation flags. - */ -static int pt_buffer_init_topa(struct pt_buffer *buf, unsigned long nr_pages, - gfp_t gfp) -{ - struct topa *topa; - int err; - - topa = topa_alloc(buf->cpu, gfp); - if (!topa) - return -ENOMEM; - - topa_insert_table(buf, topa); - - while (buf->nr_pages < nr_pages) { - err = topa_insert_pages(buf, gfp); - if (err) { - pt_buffer_fini_topa(buf); - return -ENOMEM; - } - } - - pt_buffer_setup_topa_index(buf); - - /* link last table to the first one, unless we're double buffering */ - if (pt_cap_get(PT_CAP_topa_multiple_entries)) { - TOPA_ENTRY(buf->last, -1)->base = buf->first->phys >> TOPA_SHIFT; - TOPA_ENTRY(buf->last, -1)->end = 1; - } - - pt_topa_dump(buf); - return 0; -} - -/** - * pt_buffer_setup_aux() - set up topa tables for a PT buffer - * @cpu: Cpu on which to allocate, -1 means current. - * @pages: Array of pointers to buffer pages passed from perf core. - * @nr_pages: Number of pages in the buffer. - * @snapshot: If this is a snapshot/overwrite counter. - * - * This is a pmu::setup_aux callback that sets up ToPA tables and all the - * bookkeeping for an AUX buffer. - * - * Return: Our private PT buffer structure. - */ -static void * -pt_buffer_setup_aux(int cpu, void **pages, int nr_pages, bool snapshot) -{ - struct pt_buffer *buf; - int node, ret; - - if (!nr_pages) - return NULL; - - if (cpu == -1) - cpu = raw_smp_processor_id(); - node = cpu_to_node(cpu); - - buf = kzalloc_node(offsetof(struct pt_buffer, topa_index[nr_pages]), - GFP_KERNEL, node); - if (!buf) - return NULL; - - buf->cpu = cpu; - buf->snapshot = snapshot; - buf->data_pages = pages; - - INIT_LIST_HEAD(&buf->tables); - - ret = pt_buffer_init_topa(buf, nr_pages, GFP_KERNEL); - if (ret) { - kfree(buf); - return NULL; - } - - return buf; -} - -/** - * pt_buffer_free_aux() - perf AUX deallocation path callback - * @data: PT buffer. - */ -static void pt_buffer_free_aux(void *data) -{ - struct pt_buffer *buf = data; - - pt_buffer_fini_topa(buf); - kfree(buf); -} - -/** - * pt_buffer_is_full() - check if the buffer is full - * @buf: PT buffer. - * @pt: Per-cpu pt handle. - * - * If the user hasn't read data from the output region that aux_head - * points to, the buffer is considered full: the user needs to read at - * least this region and update aux_tail to point past it. - */ -static bool pt_buffer_is_full(struct pt_buffer *buf, struct pt *pt) -{ - if (buf->snapshot) - return false; - - if (local_read(&buf->data_size) >= pt->handle.size) - return true; - - return false; -} - -/** - * intel_pt_interrupt() - PT PMI handler - */ -void intel_pt_interrupt(void) -{ - struct pt *pt = this_cpu_ptr(&pt_ctx); - struct pt_buffer *buf; - struct perf_event *event = pt->handle.event; - - /* - * There may be a dangling PT bit in the interrupt status register - * after PT has been disabled by pt_event_stop(). Make sure we don't - * do anything (particularly, re-enable) for this event here. - */ - if (!ACCESS_ONCE(pt->handle_nmi)) - return; - - pt_config_start(false); - - if (!event) - return; - - buf = perf_get_aux(&pt->handle); - if (!buf) - return; - - pt_read_offset(buf); - - pt_handle_status(pt); - - pt_update_head(pt); - - perf_aux_output_end(&pt->handle, local_xchg(&buf->data_size, 0), - local_xchg(&buf->lost, 0)); - - if (!event->hw.state) { - int ret; - - buf = perf_aux_output_begin(&pt->handle, event); - if (!buf) { - event->hw.state = PERF_HES_STOPPED; - return; - } - - pt_buffer_reset_offsets(buf, pt->handle.head); - /* snapshot counters don't use PMI, so it's safe */ - ret = pt_buffer_reset_markers(buf, &pt->handle); - if (ret) { - perf_aux_output_end(&pt->handle, 0, true); - return; - } - - pt_config_buffer(buf->cur->table, buf->cur_idx, - buf->output_off); - pt_config(event); - } -} - -/* - * PMU callbacks - */ - -static void pt_event_start(struct perf_event *event, int mode) -{ - struct pt *pt = this_cpu_ptr(&pt_ctx); - struct pt_buffer *buf = perf_get_aux(&pt->handle); - - if (!buf || pt_buffer_is_full(buf, pt)) { - event->hw.state = PERF_HES_STOPPED; - return; - } - - ACCESS_ONCE(pt->handle_nmi) = 1; - event->hw.state = 0; - - pt_config_buffer(buf->cur->table, buf->cur_idx, - buf->output_off); - pt_config(event); -} - -static void pt_event_stop(struct perf_event *event, int mode) -{ - struct pt *pt = this_cpu_ptr(&pt_ctx); - - /* - * Protect against the PMI racing with disabling wrmsr, - * see comment in intel_pt_interrupt(). - */ - ACCESS_ONCE(pt->handle_nmi) = 0; - pt_config_start(false); - - if (event->hw.state == PERF_HES_STOPPED) - return; - - event->hw.state = PERF_HES_STOPPED; - - if (mode & PERF_EF_UPDATE) { - struct pt_buffer *buf = perf_get_aux(&pt->handle); - - if (!buf) - return; - - if (WARN_ON_ONCE(pt->handle.event != event)) - return; - - pt_read_offset(buf); - - pt_handle_status(pt); - - pt_update_head(pt); - } -} - -static void pt_event_del(struct perf_event *event, int mode) -{ - struct pt *pt = this_cpu_ptr(&pt_ctx); - struct pt_buffer *buf; - - pt_event_stop(event, PERF_EF_UPDATE); - - buf = perf_get_aux(&pt->handle); - - if (buf) { - if (buf->snapshot) - pt->handle.head = - local_xchg(&buf->data_size, - buf->nr_pages << PAGE_SHIFT); - perf_aux_output_end(&pt->handle, local_xchg(&buf->data_size, 0), - local_xchg(&buf->lost, 0)); - } -} - -static int pt_event_add(struct perf_event *event, int mode) -{ - struct pt_buffer *buf; - struct pt *pt = this_cpu_ptr(&pt_ctx); - struct hw_perf_event *hwc = &event->hw; - int ret = -EBUSY; - - if (pt->handle.event) - goto fail; - - buf = perf_aux_output_begin(&pt->handle, event); - ret = -EINVAL; - if (!buf) - goto fail_stop; - - pt_buffer_reset_offsets(buf, pt->handle.head); - if (!buf->snapshot) { - ret = pt_buffer_reset_markers(buf, &pt->handle); - if (ret) - goto fail_end_stop; - } - - if (mode & PERF_EF_START) { - pt_event_start(event, 0); - ret = -EBUSY; - if (hwc->state == PERF_HES_STOPPED) - goto fail_end_stop; - } else { - hwc->state = PERF_HES_STOPPED; - } - - return 0; - -fail_end_stop: - perf_aux_output_end(&pt->handle, 0, true); -fail_stop: - hwc->state = PERF_HES_STOPPED; -fail: - return ret; -} - -static void pt_event_read(struct perf_event *event) -{ -} - -static void pt_event_destroy(struct perf_event *event) -{ - x86_del_exclusive(x86_lbr_exclusive_pt); -} - -static int pt_event_init(struct perf_event *event) -{ - if (event->attr.type != pt_pmu.pmu.type) - return -ENOENT; - - if (!pt_event_valid(event)) - return -EINVAL; - - if (x86_add_exclusive(x86_lbr_exclusive_pt)) - return -EBUSY; - - event->destroy = pt_event_destroy; - - return 0; -} - -void cpu_emergency_stop_pt(void) -{ - struct pt *pt = this_cpu_ptr(&pt_ctx); - - if (pt->handle.event) - pt_event_stop(pt->handle.event, PERF_EF_UPDATE); -} - -static __init int pt_init(void) -{ - int ret, cpu, prior_warn = 0; - - BUILD_BUG_ON(sizeof(struct topa) > PAGE_SIZE); - - if (!test_cpu_cap(&boot_cpu_data, X86_FEATURE_INTEL_PT)) - return -ENODEV; - - get_online_cpus(); - for_each_online_cpu(cpu) { - u64 ctl; - - ret = rdmsrl_safe_on_cpu(cpu, MSR_IA32_RTIT_CTL, &ctl); - if (!ret && (ctl & RTIT_CTL_TRACEEN)) - prior_warn++; - } - put_online_cpus(); - - if (prior_warn) { - x86_add_exclusive(x86_lbr_exclusive_pt); - pr_warn("PT is enabled at boot time, doing nothing\n"); - - return -EBUSY; - } - - ret = pt_pmu_hw_init(); - if (ret) - return ret; - - if (!pt_cap_get(PT_CAP_topa_output)) { - pr_warn("ToPA output is not supported on this CPU\n"); - return -ENODEV; - } - - if (!pt_cap_get(PT_CAP_topa_multiple_entries)) - pt_pmu.pmu.capabilities = - PERF_PMU_CAP_AUX_NO_SG | PERF_PMU_CAP_AUX_SW_DOUBLEBUF; - - pt_pmu.pmu.capabilities |= PERF_PMU_CAP_EXCLUSIVE | PERF_PMU_CAP_ITRACE; - pt_pmu.pmu.attr_groups = pt_attr_groups; - pt_pmu.pmu.task_ctx_nr = perf_sw_context; - pt_pmu.pmu.event_init = pt_event_init; - pt_pmu.pmu.add = pt_event_add; - pt_pmu.pmu.del = pt_event_del; - pt_pmu.pmu.start = pt_event_start; - pt_pmu.pmu.stop = pt_event_stop; - pt_pmu.pmu.read = pt_event_read; - pt_pmu.pmu.setup_aux = pt_buffer_setup_aux; - pt_pmu.pmu.free_aux = pt_buffer_free_aux; - ret = perf_pmu_register(&pt_pmu.pmu, "intel_pt", -1); - - return ret; -} -arch_initcall(pt_init); |