diff options
Diffstat (limited to 'arch/x86/events/intel/pt.c')
| -rw-r--r-- | arch/x86/events/intel/pt.c | 1798 |
1 files changed, 1798 insertions, 0 deletions
diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c new file mode 100644 index 000000000..5667b8b99 --- /dev/null +++ b/arch/x86/events/intel/pt.c @@ -0,0 +1,1798 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Intel(R) Processor Trace PMU driver for perf + * Copyright (c) 2013-2014, Intel Corporation. + * + * 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/bits.h> +#include <linux/limits.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 <asm/intel-family.h> + +#include "../perf_event.h" +#include "pt.h" + +static DEFINE_PER_CPU(struct pt, pt_ctx); + +static struct pt_pmu pt_pmu; + +/* + * 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, CPUID_EAX, 0xffffffff), + PT_CAP(cr3_filtering, 0, CPUID_EBX, BIT(0)), + PT_CAP(psb_cyc, 0, CPUID_EBX, BIT(1)), + PT_CAP(ip_filtering, 0, CPUID_EBX, BIT(2)), + PT_CAP(mtc, 0, CPUID_EBX, BIT(3)), + PT_CAP(ptwrite, 0, CPUID_EBX, BIT(4)), + PT_CAP(power_event_trace, 0, CPUID_EBX, BIT(5)), + PT_CAP(topa_output, 0, CPUID_ECX, BIT(0)), + PT_CAP(topa_multiple_entries, 0, CPUID_ECX, BIT(1)), + PT_CAP(single_range_output, 0, CPUID_ECX, BIT(2)), + PT_CAP(output_subsys, 0, CPUID_ECX, BIT(3)), + PT_CAP(payloads_lip, 0, CPUID_ECX, BIT(31)), + PT_CAP(num_address_ranges, 1, CPUID_EAX, 0x7), + PT_CAP(mtc_periods, 1, CPUID_EAX, 0xffff0000), + PT_CAP(cycle_thresholds, 1, CPUID_EBX, 0xffff), + PT_CAP(psb_periods, 1, CPUID_EBX, 0xffff0000), +}; + +u32 intel_pt_validate_cap(u32 *caps, enum pt_capabilities capability) +{ + struct pt_cap_desc *cd = &pt_caps[capability]; + u32 c = caps[cd->leaf * PT_CPUID_REGS_NUM + cd->reg]; + unsigned int shift = __ffs(cd->mask); + + return (c & cd->mask) >> shift; +} +EXPORT_SYMBOL_GPL(intel_pt_validate_cap); + +u32 intel_pt_validate_hw_cap(enum pt_capabilities cap) +{ + return intel_pt_validate_cap(pt_pmu.caps, cap); +} +EXPORT_SYMBOL_GPL(intel_pt_validate_hw_cap); + +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", intel_pt_validate_hw_cap(cap)); +} + +static struct attribute_group pt_cap_group __ro_after_init = { + .name = "caps", +}; + +PMU_FORMAT_ATTR(pt, "config:0" ); +PMU_FORMAT_ATTR(cyc, "config:1" ); +PMU_FORMAT_ATTR(pwr_evt, "config:4" ); +PMU_FORMAT_ATTR(fup_on_ptw, "config:5" ); +PMU_FORMAT_ATTR(mtc, "config:9" ); +PMU_FORMAT_ATTR(tsc, "config:10" ); +PMU_FORMAT_ATTR(noretcomp, "config:11" ); +PMU_FORMAT_ATTR(ptw, "config:12" ); +PMU_FORMAT_ATTR(branch, "config:13" ); +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_pt.attr, + &format_attr_cyc.attr, + &format_attr_pwr_evt.attr, + &format_attr_fup_on_ptw.attr, + &format_attr_mtc.attr, + &format_attr_tsc.attr, + &format_attr_noretcomp.attr, + &format_attr_ptw.attr, + &format_attr_branch.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 ssize_t +pt_timing_attr_show(struct device *dev, struct device_attribute *attr, + char *page) +{ + struct perf_pmu_events_attr *pmu_attr = + container_of(attr, struct perf_pmu_events_attr, attr); + + switch (pmu_attr->id) { + case 0: + return sprintf(page, "%lu\n", pt_pmu.max_nonturbo_ratio); + case 1: + return sprintf(page, "%u:%u\n", + pt_pmu.tsc_art_num, + pt_pmu.tsc_art_den); + default: + break; + } + + return -EINVAL; +} + +PMU_EVENT_ATTR(max_nonturbo_ratio, timing_attr_max_nonturbo_ratio, 0, + pt_timing_attr_show); +PMU_EVENT_ATTR(tsc_art_ratio, timing_attr_tsc_art_ratio, 1, + pt_timing_attr_show); + +static struct attribute *pt_timing_attr[] = { + &timing_attr_max_nonturbo_ratio.attr.attr, + &timing_attr_tsc_art_ratio.attr.attr, + NULL, +}; + +static struct attribute_group pt_timing_group = { + .attrs = pt_timing_attr, +}; + +static const struct attribute_group *pt_attr_groups[] = { + &pt_cap_group, + &pt_format_group, + &pt_timing_group, + NULL, +}; + +static int __init pt_pmu_hw_init(void) +{ + struct dev_ext_attribute *de_attrs; + struct attribute **attrs; + size_t size; + u64 reg; + int ret; + long i; + + rdmsrl(MSR_PLATFORM_INFO, reg); + pt_pmu.max_nonturbo_ratio = (reg & 0xff00) >> 8; + + /* + * if available, read in TSC to core crystal clock ratio, + * otherwise, zero for numerator stands for "not enumerated" + * as per SDM + */ + if (boot_cpu_data.cpuid_level >= CPUID_TSC_LEAF) { + u32 eax, ebx, ecx, edx; + + cpuid(CPUID_TSC_LEAF, &eax, &ebx, &ecx, &edx); + + pt_pmu.tsc_art_num = ebx; + pt_pmu.tsc_art_den = eax; + } + + /* model-specific quirks */ + switch (boot_cpu_data.x86_model) { + case INTEL_FAM6_BROADWELL: + case INTEL_FAM6_BROADWELL_D: + case INTEL_FAM6_BROADWELL_G: + case INTEL_FAM6_BROADWELL_X: + /* not setting BRANCH_EN will #GP, erratum BDM106 */ + pt_pmu.branch_en_always_on = true; + break; + default: + break; + } + + if (boot_cpu_has(X86_FEATURE_VMX)) { + /* + * Intel SDM, 36.5 "Tracing post-VMXON" says that + * "IA32_VMX_MISC[bit 14]" being 1 means PT can trace + * post-VMXON. + */ + rdmsrl(MSR_IA32_VMX_MISC, reg); + if (reg & BIT(14)) + pt_pmu.vmx = true; + } + + for (i = 0; i < PT_CPUID_LEAVES; i++) { + cpuid_count(20, i, + &pt_pmu.caps[CPUID_EAX + i*PT_CPUID_REGS_NUM], + &pt_pmu.caps[CPUID_EBX + i*PT_CPUID_REGS_NUM], + &pt_pmu.caps[CPUID_ECX + i*PT_CPUID_REGS_NUM], + &pt_pmu.caps[CPUID_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 RTIT_CTL_PTW (RTIT_CTL_PTW_EN | \ + RTIT_CTL_FUP_ON_PTW) + +/* + * Bit 0 (TraceEn) in the attr.config is meaningless as the + * corresponding bit in the RTIT_CTL can only be controlled + * by the driver; therefore, repurpose it to mean: pass + * through the bit that was previously assumed to be always + * on for PT, thereby allowing the user to *not* set it if + * they so wish. See also pt_event_valid() and pt_config(). + */ +#define RTIT_CTL_PASSTHROUGH RTIT_CTL_TRACEEN + +#define PT_CONFIG_MASK (RTIT_CTL_TRACEEN | \ + RTIT_CTL_TSC_EN | \ + RTIT_CTL_DISRETC | \ + RTIT_CTL_BRANCH_EN | \ + RTIT_CTL_CYC_PSB | \ + RTIT_CTL_MTC | \ + RTIT_CTL_PWR_EVT_EN | \ + RTIT_CTL_FUP_ON_PTW | \ + RTIT_CTL_PTW_EN) + +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 (!intel_pt_validate_hw_cap(PT_CAP_psb_cyc)) + return false; + + allowed = intel_pt_validate_hw_cap(PT_CAP_psb_periods); + requested = (config & RTIT_CTL_PSB_FREQ) >> + RTIT_CTL_PSB_FREQ_OFFSET; + if (requested && (!(allowed & BIT(requested)))) + return false; + + allowed = intel_pt_validate_hw_cap(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 (!intel_pt_validate_hw_cap(PT_CAP_mtc)) + return false; + + allowed = intel_pt_validate_hw_cap(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; + } + + if (config & RTIT_CTL_PWR_EVT_EN && + !intel_pt_validate_hw_cap(PT_CAP_power_event_trace)) + return false; + + if (config & RTIT_CTL_PTW) { + if (!intel_pt_validate_hw_cap(PT_CAP_ptwrite)) + return false; + + /* FUPonPTW without PTW doesn't make sense */ + if ((config & RTIT_CTL_FUP_ON_PTW) && + !(config & RTIT_CTL_PTW_EN)) + return false; + } + + /* + * Setting bit 0 (TraceEn in RTIT_CTL MSR) in the attr.config + * clears the assomption that BranchEn must always be enabled, + * as was the case with the first implementation of PT. + * If this bit is not set, the legacy behavior is preserved + * for compatibility with the older userspace. + * + * Re-using bit 0 for this purpose is fine because it is never + * directly set by the user; previous attempts at setting it in + * the attr.config resulted in -EINVAL. + */ + if (config & RTIT_CTL_PASSTHROUGH) { + /* + * Disallow not setting BRANCH_EN where BRANCH_EN is + * always required. + */ + if (pt_pmu.branch_en_always_on && + !(config & RTIT_CTL_BRANCH_EN)) + return false; + } else { + /* + * Disallow BRANCH_EN without the PASSTHROUGH. + */ + if (config & RTIT_CTL_BRANCH_EN) + return false; + } + + return true; +} + +/* + * PT configuration helpers + * These all are cpu affine and operate on a local PT + */ + +static void pt_config_start(struct perf_event *event) +{ + struct pt *pt = this_cpu_ptr(&pt_ctx); + u64 ctl = event->hw.config; + + ctl |= RTIT_CTL_TRACEEN; + if (READ_ONCE(pt->vmx_on)) + perf_aux_output_flag(&pt->handle, PERF_AUX_FLAG_PARTIAL); + else + wrmsrl(MSR_IA32_RTIT_CTL, ctl); + + WRITE_ONCE(event->hw.config, ctl); +} + +/* Address ranges and their corresponding msr configuration registers */ +static const struct pt_address_range { + unsigned long msr_a; + unsigned long msr_b; + unsigned int reg_off; +} pt_address_ranges[] = { + { + .msr_a = MSR_IA32_RTIT_ADDR0_A, + .msr_b = MSR_IA32_RTIT_ADDR0_B, + .reg_off = RTIT_CTL_ADDR0_OFFSET, + }, + { + .msr_a = MSR_IA32_RTIT_ADDR1_A, + .msr_b = MSR_IA32_RTIT_ADDR1_B, + .reg_off = RTIT_CTL_ADDR1_OFFSET, + }, + { + .msr_a = MSR_IA32_RTIT_ADDR2_A, + .msr_b = MSR_IA32_RTIT_ADDR2_B, + .reg_off = RTIT_CTL_ADDR2_OFFSET, + }, + { + .msr_a = MSR_IA32_RTIT_ADDR3_A, + .msr_b = MSR_IA32_RTIT_ADDR3_B, + .reg_off = RTIT_CTL_ADDR3_OFFSET, + } +}; + +static u64 pt_config_filters(struct perf_event *event) +{ + struct pt_filters *filters = event->hw.addr_filters; + struct pt *pt = this_cpu_ptr(&pt_ctx); + unsigned int range = 0; + u64 rtit_ctl = 0; + + if (!filters) + return 0; + + perf_event_addr_filters_sync(event); + + for (range = 0; range < filters->nr_filters; range++) { + struct pt_filter *filter = &filters->filter[range]; + + /* + * Note, if the range has zero start/end addresses due + * to its dynamic object not being loaded yet, we just + * go ahead and program zeroed range, which will simply + * produce no data. Note^2: if executable code at 0x0 + * is a concern, we can set up an "invalid" configuration + * such as msr_b < msr_a. + */ + + /* avoid redundant msr writes */ + if (pt->filters.filter[range].msr_a != filter->msr_a) { + wrmsrl(pt_address_ranges[range].msr_a, filter->msr_a); + pt->filters.filter[range].msr_a = filter->msr_a; + } + + if (pt->filters.filter[range].msr_b != filter->msr_b) { + wrmsrl(pt_address_ranges[range].msr_b, filter->msr_b); + pt->filters.filter[range].msr_b = filter->msr_b; + } + + rtit_ctl |= (u64)filter->config << pt_address_ranges[range].reg_off; + } + + return rtit_ctl; +} + +static void pt_config(struct perf_event *event) +{ + struct pt *pt = this_cpu_ptr(&pt_ctx); + struct pt_buffer *buf = perf_get_aux(&pt->handle); + u64 reg; + + /* First round: clear STATUS, in particular the PSB byte counter. */ + if (!event->hw.config) { + perf_event_itrace_started(event); + wrmsrl(MSR_IA32_RTIT_STATUS, 0); + } + + reg = pt_config_filters(event); + reg |= RTIT_CTL_TRACEEN; + if (!buf->single) + reg |= RTIT_CTL_TOPA; + + /* + * Previously, we had BRANCH_EN on by default, but now that PT has + * grown features outside of branch tracing, it is useful to allow + * the user to disable it. Setting bit 0 in the event's attr.config + * allows BRANCH_EN to pass through instead of being always on. See + * also the comment in pt_event_valid(). + */ + if (event->attr.config & BIT(0)) { + reg |= event->attr.config & RTIT_CTL_BRANCH_EN; + } else { + reg |= RTIT_CTL_BRANCH_EN; + } + + 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); + + event->hw.config = reg; + pt_config_start(event); +} + +static void pt_config_stop(struct perf_event *event) +{ + struct pt *pt = this_cpu_ptr(&pt_ctx); + u64 ctl = READ_ONCE(event->hw.config); + + /* may be already stopped by a PMI */ + if (!(ctl & RTIT_CTL_TRACEEN)) + return; + + ctl &= ~RTIT_CTL_TRACEEN; + if (!READ_ONCE(pt->vmx_on)) + wrmsrl(MSR_IA32_RTIT_CTL, ctl); + + WRITE_ONCE(event->hw.config, 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. + */ + wmb(); +} + +/** + * struct topa - ToPA metadata + * @list: linkage to struct pt_buffer's list of tables + * @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 + * @z_count: how many times the first entry repeats + */ +struct topa { + struct list_head list; + u64 offset; + size_t size; + int last; + unsigned int z_count; +}; + +/* + * 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 - sizeof(struct topa)) / sizeof(struct topa_entry)) + +/** + * struct topa_page - page-sized ToPA table with metadata at the top + * @table: actual ToPA table entries, as understood by PT hardware + * @topa: metadata + */ +struct topa_page { + struct topa_entry table[TENTS_PER_PAGE]; + struct topa topa; +}; + +static inline struct topa_page *topa_to_page(struct topa *topa) +{ + return container_of(topa, struct topa_page, topa); +} + +static inline struct topa_page *topa_entry_to_page(struct topa_entry *te) +{ + return (struct topa_page *)((unsigned long)te & PAGE_MASK); +} + +static inline phys_addr_t topa_pfn(struct topa *topa) +{ + return PFN_DOWN(virt_to_phys(topa_to_page(topa))); +} + +/* make -1 stand for the last table entry */ +#define TOPA_ENTRY(t, i) \ + ((i) == -1 \ + ? &topa_to_page(t)->table[(t)->last] \ + : &topa_to_page(t)->table[(i)]) +#define TOPA_ENTRY_SIZE(t, i) (sizes(TOPA_ENTRY((t), (i))->size)) +#define TOPA_ENTRY_PAGES(t, i) (1 << TOPA_ENTRY((t), (i))->size) + +static void pt_config_buffer(struct pt_buffer *buf) +{ + struct pt *pt = this_cpu_ptr(&pt_ctx); + u64 reg, mask; + void *base; + + if (buf->single) { + base = buf->data_pages[0]; + mask = (buf->nr_pages * PAGE_SIZE - 1) >> 7; + } else { + base = topa_to_page(buf->cur)->table; + mask = (u64)buf->cur_idx; + } + + reg = virt_to_phys(base); + if (pt->output_base != reg) { + pt->output_base = reg; + wrmsrl(MSR_IA32_RTIT_OUTPUT_BASE, reg); + } + + reg = 0x7f | (mask << 7) | ((u64)buf->output_off << 32); + if (pt->output_mask != reg) { + pt->output_mask = reg; + wrmsrl(MSR_IA32_RTIT_OUTPUT_MASK, reg); + } +} + +/** + * 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_page *tp; + struct page *p; + + p = alloc_pages_node(node, gfp | __GFP_ZERO, 0); + if (!p) + return NULL; + + tp = page_address(p); + tp->topa.last = 0; + + /* + * In case of singe-entry ToPA, always put the self-referencing END + * link as the 2nd entry in the table + */ + if (!intel_pt_validate_hw_cap(PT_CAP_topa_multiple_entries)) { + TOPA_ENTRY(&tp->topa, 1)->base = page_to_phys(p) >> TOPA_SHIFT; + TOPA_ENTRY(&tp->topa, 1)->end = 1; + } + + return &tp->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 (!intel_pt_validate_hw_cap(PT_CAP_topa_multiple_entries)) + return; + + BUG_ON(last->last != TENTS_PER_PAGE - 1); + + TOPA_ENTRY(last, -1)->base = topa_pfn(topa); + 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 (!intel_pt_validate_hw_cap(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, int cpu, 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(cpu, gfp); + if (!topa) + return -ENOMEM; + + topa_insert_table(buf, topa); + } + + if (topa->z_count == topa->last - 1) { + if (order == TOPA_ENTRY(topa, topa->last - 1)->size) + topa->z_count++; + } + + TOPA_ENTRY(topa, -1)->base = page_to_phys(p) >> TOPA_SHIFT; + TOPA_ENTRY(topa, -1)->size = order; + if (!buf->snapshot && + !intel_pt_validate_hw_cap(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) { + struct topa_page *tp = topa_to_page(topa); + int i; + + pr_debug("# table @%p, off %llx size %zx\n", tp->table, + 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", + &tp->table[i], + (unsigned long)tp->table[i].base << TOPA_SHIFT, + sizes(tp->table[i].size), + tp->table[i].end ? 'E' : ' ', + tp->table[i].intr ? 'I' : ' ', + tp->table[i].stop ? 'S' : ' ', + *(u64 *)&tp->table[i]); + if ((intel_pt_validate_hw_cap(PT_CAP_topa_multiple_entries) && + tp->table[i].stop) || + tp->table[i].end) + break; + if (!i && topa->z_count) + i += topa->z_count; + } + } +} + +/** + * 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; + + if (buf->single) { + local_set(&buf->data_size, buf->output_off); + return; + } + + /* 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 += TOPA_ENTRY_SIZE(buf->cur, topa_idx); + + 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(TOPA_ENTRY(buf->cur, 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 TOPA_ENTRY_SIZE(buf->cur, buf->cur_idx); +} + +/** + * 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 (!buf->single && + (!intel_pt_validate_hw_cap(PT_CAP_topa_multiple_entries) || + buf->output_off == pt_buffer_region_size(buf))) { + perf_aux_output_flag(&pt->handle, + PERF_AUX_FLAG_TRUNCATED); + advance++; + } + } + + /* + * Also on single-entry ToPA implementations, interrupt will come + * before the output reaches its output region's boundary. + */ + if (!intel_pt_validate_hw_cap(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) +{ + struct pt *pt = this_cpu_ptr(&pt_ctx); + struct topa_page *tp; + + if (!buf->single) { + rdmsrl(MSR_IA32_RTIT_OUTPUT_BASE, pt->output_base); + tp = phys_to_virt(pt->output_base); + buf->cur = &tp->topa; + } + + rdmsrl(MSR_IA32_RTIT_OUTPUT_MASK, pt->output_mask); + /* offset within current output region */ + buf->output_off = pt->output_mask >> 32; + /* index of current output region within this table */ + if (!buf->single) + buf->cur_idx = (pt->output_mask & 0xffffff80) >> 7; +} + +static struct topa_entry * +pt_topa_entry_for_page(struct pt_buffer *buf, unsigned int pg) +{ + struct topa_page *tp; + struct topa *topa; + unsigned int idx, cur_pg = 0, z_pg = 0, start_idx = 0; + + /* + * Indicates a bug in the caller. + */ + if (WARN_ON_ONCE(pg >= buf->nr_pages)) + return NULL; + + /* + * First, find the ToPA table where @pg fits. With high + * order allocations, there shouldn't be many of these. + */ + list_for_each_entry(topa, &buf->tables, list) { + if (topa->offset + topa->size > pg << PAGE_SHIFT) + goto found; + } + + /* + * Hitting this means we have a problem in the ToPA + * allocation code. + */ + WARN_ON_ONCE(1); + + return NULL; + +found: + /* + * Indicates a problem in the ToPA allocation code. + */ + if (WARN_ON_ONCE(topa->last == -1)) + return NULL; + + tp = topa_to_page(topa); + cur_pg = PFN_DOWN(topa->offset); + if (topa->z_count) { + z_pg = TOPA_ENTRY_PAGES(topa, 0) * (topa->z_count + 1); + start_idx = topa->z_count + 1; + } + + /* + * Multiple entries at the beginning of the table have the same size, + * ideally all of them; if @pg falls there, the search is done. + */ + if (pg >= cur_pg && pg < cur_pg + z_pg) { + idx = (pg - cur_pg) / TOPA_ENTRY_PAGES(topa, 0); + return &tp->table[idx]; + } + + /* + * Otherwise, slow path: iterate through the remaining entries. + */ + for (idx = start_idx, cur_pg += z_pg; idx < topa->last; idx++) { + if (cur_pg + TOPA_ENTRY_PAGES(topa, idx) > pg) + return &tp->table[idx]; + + cur_pg += TOPA_ENTRY_PAGES(topa, idx); + } + + /* + * Means we couldn't find a ToPA entry in the table that does match. + */ + WARN_ON_ONCE(1); + + return NULL; +} + +static struct topa_entry * +pt_topa_prev_entry(struct pt_buffer *buf, struct topa_entry *te) +{ + unsigned long table = (unsigned long)te & ~(PAGE_SIZE - 1); + struct topa_page *tp; + struct topa *topa; + + tp = (struct topa_page *)table; + if (tp->table != te) + return --te; + + topa = &tp->topa; + if (topa == buf->first) + topa = buf->last; + else + topa = list_prev_entry(topa, list); + + tp = topa_to_page(topa); + + return &tp->table[topa->last - 1]; +} + +/** + * 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; + + if (buf->single) + return 0; + + /* can't stop in the middle of an output region */ + if (buf->output_off + handle->size + 1 < pt_buffer_region_size(buf)) { + perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED); + return -EINVAL; + } + + + /* single entry ToPA is handled by marking all regions STOP=1 INT=1 */ + if (!intel_pt_validate_hw_cap(PT_CAP_topa_multiple_entries)) + return 0; + + /* clear STOP and INT from current entry */ + if (buf->stop_te) { + buf->stop_te->stop = 0; + buf->stop_te->intr = 0; + } + + if (buf->intr_te) + buf->intr_te->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; + + if (idx != buf->stop_pos) { + buf->stop_pos = idx; + buf->stop_te = pt_topa_entry_for_page(buf, idx); + buf->stop_te = pt_topa_prev_entry(buf, buf->stop_te); + } + + 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; + if (idx != buf->intr_pos) { + buf->intr_pos = idx; + buf->intr_te = pt_topa_entry_for_page(buf, idx); + buf->intr_te = pt_topa_prev_entry(buf, buf->intr_te); + } + + buf->stop_te->stop = 1; + buf->stop_te->intr = 1; + buf->intr_te->intr = 1; + + return 0; +} + +/** + * 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) +{ + struct topa_page *cur_tp; + struct topa_entry *te; + int pg; + + if (buf->snapshot) + head &= (buf->nr_pages << PAGE_SHIFT) - 1; + + if (!buf->single) { + pg = (head >> PAGE_SHIFT) & (buf->nr_pages - 1); + te = pt_topa_entry_for_page(buf, pg); + + cur_tp = topa_entry_to_page(te); + buf->cur = &cur_tp->topa; + buf->cur_idx = te - TOPA_ENTRY(buf->cur, 0); + buf->output_off = head & (pt_buffer_region_size(buf) - 1); + } else { + buf->output_off = head; + } + + 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; + + if (buf->single) + return; + + 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, int cpu, + unsigned long nr_pages, gfp_t gfp) +{ + struct topa *topa; + int err; + + topa = topa_alloc(cpu, gfp); + if (!topa) + return -ENOMEM; + + topa_insert_table(buf, topa); + + while (buf->nr_pages < nr_pages) { + err = topa_insert_pages(buf, cpu, gfp); + if (err) { + pt_buffer_fini_topa(buf); + return -ENOMEM; + } + } + + /* link last table to the first one, unless we're double buffering */ + if (intel_pt_validate_hw_cap(PT_CAP_topa_multiple_entries)) { + TOPA_ENTRY(buf->last, -1)->base = topa_pfn(buf->first); + TOPA_ENTRY(buf->last, -1)->end = 1; + } + + pt_topa_dump(buf); + return 0; +} + +static int pt_buffer_try_single(struct pt_buffer *buf, int nr_pages) +{ + struct page *p = virt_to_page(buf->data_pages[0]); + int ret = -ENOTSUPP, order = 0; + + /* + * We can use single range output mode + * + in snapshot mode, where we don't need interrupts; + * + if the hardware supports it; + * + if the entire buffer is one contiguous allocation. + */ + if (!buf->snapshot) + goto out; + + if (!intel_pt_validate_hw_cap(PT_CAP_single_range_output)) + goto out; + + if (PagePrivate(p)) + order = page_private(p); + + if (1 << order != nr_pages) + goto out; + + /* + * Some processors cannot always support single range for more than + * 4KB - refer errata TGL052, ADL037 and RPL017. Future processors might + * also be affected, so for now rather than trying to keep track of + * which ones, just disable it for all. + */ + if (nr_pages > 1) + goto out; + + buf->single = true; + buf->nr_pages = nr_pages; + ret = 0; +out: + return ret; +} + +/** + * 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(struct perf_event *event, void **pages, + int nr_pages, bool snapshot) +{ + struct pt_buffer *buf; + int node, ret, cpu = event->cpu; + + if (!nr_pages) + return NULL; + + /* + * Only support AUX sampling in snapshot mode, where we don't + * generate NMIs. + */ + if (event->attr.aux_sample_size && !snapshot) + return NULL; + + if (cpu == -1) + cpu = raw_smp_processor_id(); + node = cpu_to_node(cpu); + + buf = kzalloc_node(sizeof(struct pt_buffer), GFP_KERNEL, node); + if (!buf) + return NULL; + + buf->snapshot = snapshot; + buf->data_pages = pages; + buf->stop_pos = -1; + buf->intr_pos = -1; + + INIT_LIST_HEAD(&buf->tables); + + ret = pt_buffer_try_single(buf, nr_pages); + if (!ret) + return buf; + + ret = pt_buffer_init_topa(buf, cpu, 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); +} + +static int pt_addr_filters_init(struct perf_event *event) +{ + struct pt_filters *filters; + int node = event->cpu == -1 ? -1 : cpu_to_node(event->cpu); + + if (!intel_pt_validate_hw_cap(PT_CAP_num_address_ranges)) + return 0; + + filters = kzalloc_node(sizeof(struct pt_filters), GFP_KERNEL, node); + if (!filters) + return -ENOMEM; + + if (event->parent) + memcpy(filters, event->parent->hw.addr_filters, + sizeof(*filters)); + + event->hw.addr_filters = filters; + + return 0; +} + +static void pt_addr_filters_fini(struct perf_event *event) +{ + kfree(event->hw.addr_filters); + event->hw.addr_filters = NULL; +} + +#ifdef CONFIG_X86_64 +/* Clamp to a canonical address greater-than-or-equal-to the address given */ +static u64 clamp_to_ge_canonical_addr(u64 vaddr, u8 vaddr_bits) +{ + return __is_canonical_address(vaddr, vaddr_bits) ? + vaddr : + -BIT_ULL(vaddr_bits - 1); +} + +/* Clamp to a canonical address less-than-or-equal-to the address given */ +static u64 clamp_to_le_canonical_addr(u64 vaddr, u8 vaddr_bits) +{ + return __is_canonical_address(vaddr, vaddr_bits) ? + vaddr : + BIT_ULL(vaddr_bits - 1) - 1; +} +#else +#define clamp_to_ge_canonical_addr(x, y) (x) +#define clamp_to_le_canonical_addr(x, y) (x) +#endif + +static int pt_event_addr_filters_validate(struct list_head *filters) +{ + struct perf_addr_filter *filter; + int range = 0; + + list_for_each_entry(filter, filters, entry) { + /* + * PT doesn't support single address triggers and + * 'start' filters. + */ + if (!filter->size || + filter->action == PERF_ADDR_FILTER_ACTION_START) + return -EOPNOTSUPP; + + if (++range > intel_pt_validate_hw_cap(PT_CAP_num_address_ranges)) + return -EOPNOTSUPP; + } + + return 0; +} + +static void pt_event_addr_filters_sync(struct perf_event *event) +{ + struct perf_addr_filters_head *head = perf_event_addr_filters(event); + unsigned long msr_a, msr_b; + struct perf_addr_filter_range *fr = event->addr_filter_ranges; + struct pt_filters *filters = event->hw.addr_filters; + struct perf_addr_filter *filter; + int range = 0; + + if (!filters) + return; + + list_for_each_entry(filter, &head->list, entry) { + if (filter->path.dentry && !fr[range].start) { + msr_a = msr_b = 0; + } else { + unsigned long n = fr[range].size - 1; + unsigned long a = fr[range].start; + unsigned long b; + + if (a > ULONG_MAX - n) + b = ULONG_MAX; + else + b = a + n; + /* + * Apply the offset. 64-bit addresses written to the + * MSRs must be canonical, but the range can encompass + * non-canonical addresses. Since software cannot + * execute at non-canonical addresses, adjusting to + * canonical addresses does not affect the result of the + * address filter. + */ + msr_a = clamp_to_ge_canonical_addr(a, boot_cpu_data.x86_virt_bits); + msr_b = clamp_to_le_canonical_addr(b, boot_cpu_data.x86_virt_bits); + if (msr_b < msr_a) + msr_a = msr_b = 0; + } + + filters->filter[range].msr_a = msr_a; + filters->filter[range].msr_b = msr_b; + if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER) + filters->filter[range].config = 1; + else + filters->filter[range].config = 2; + range++; + } + + filters->nr_filters = range; +} + +/** + * 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 (!READ_ONCE(pt->handle_nmi)) + return; + + if (!event) + return; + + pt_config_stop(event); + + 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)); + + 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); + return; + } + + pt_config_buffer(buf); + pt_config_start(event); + } +} + +void intel_pt_handle_vmx(int on) +{ + struct pt *pt = this_cpu_ptr(&pt_ctx); + struct perf_event *event; + unsigned long flags; + + /* PT plays nice with VMX, do nothing */ + if (pt_pmu.vmx) + return; + + /* + * VMXON will clear RTIT_CTL.TraceEn; we need to make + * sure to not try to set it while VMX is on. Disable + * interrupts to avoid racing with pmu callbacks; + * concurrent PMI should be handled fine. + */ + local_irq_save(flags); + WRITE_ONCE(pt->vmx_on, on); + + /* + * If an AUX transaction is in progress, it will contain + * gap(s), so flag it PARTIAL to inform the user. + */ + event = pt->handle.event; + if (event) + perf_aux_output_flag(&pt->handle, + PERF_AUX_FLAG_PARTIAL); + + /* Turn PTs back on */ + if (!on && event) + wrmsrl(MSR_IA32_RTIT_CTL, event->hw.config); + + local_irq_restore(flags); +} +EXPORT_SYMBOL_GPL(intel_pt_handle_vmx); + +/* + * PMU callbacks + */ + +static void pt_event_start(struct perf_event *event, int mode) +{ + struct hw_perf_event *hwc = &event->hw; + struct pt *pt = this_cpu_ptr(&pt_ctx); + struct pt_buffer *buf; + + buf = perf_aux_output_begin(&pt->handle, event); + if (!buf) + goto fail_stop; + + pt_buffer_reset_offsets(buf, pt->handle.head); + if (!buf->snapshot) { + if (pt_buffer_reset_markers(buf, &pt->handle)) + goto fail_end_stop; + } + + WRITE_ONCE(pt->handle_nmi, 1); + hwc->state = 0; + + pt_config_buffer(buf); + pt_config(event); + + return; + +fail_end_stop: + perf_aux_output_end(&pt->handle, 0); +fail_stop: + hwc->state = PERF_HES_STOPPED; +} + +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(). + */ + WRITE_ONCE(pt->handle_nmi, 0); + + pt_config_stop(event); + + 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); + + 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)); + } +} + +static long pt_event_snapshot_aux(struct perf_event *event, + struct perf_output_handle *handle, + unsigned long size) +{ + struct pt *pt = this_cpu_ptr(&pt_ctx); + struct pt_buffer *buf = perf_get_aux(&pt->handle); + unsigned long from = 0, to; + long ret; + + if (WARN_ON_ONCE(!buf)) + return 0; + + /* + * Sampling is only allowed on snapshot events; + * see pt_buffer_setup_aux(). + */ + if (WARN_ON_ONCE(!buf->snapshot)) + return 0; + + /* + * Here, handle_nmi tells us if the tracing is on + */ + if (READ_ONCE(pt->handle_nmi)) + pt_config_stop(event); + + pt_read_offset(buf); + pt_update_head(pt); + + to = local_read(&buf->data_size); + if (to < size) + from = buf->nr_pages << PAGE_SHIFT; + from += to - size; + + ret = perf_output_copy_aux(&pt->handle, handle, from, to); + + /* + * If the tracing was on when we turned up, restart it. + * Compiler barrier not needed as we couldn't have been + * preempted by anything that touches pt->handle_nmi. + */ + if (pt->handle_nmi) + pt_config_start(event); + + return ret; +} + +static void pt_event_del(struct perf_event *event, int mode) +{ + pt_event_stop(event, PERF_EF_UPDATE); +} + +static int pt_event_add(struct perf_event *event, int mode) +{ + struct pt *pt = this_cpu_ptr(&pt_ctx); + struct hw_perf_event *hwc = &event->hw; + int ret = -EBUSY; + + if (pt->handle.event) + goto fail; + + if (mode & PERF_EF_START) { + pt_event_start(event, 0); + ret = -EINVAL; + if (hwc->state == PERF_HES_STOPPED) + goto fail; + } else { + hwc->state = PERF_HES_STOPPED; + } + + ret = 0; +fail: + + return ret; +} + +static void pt_event_read(struct perf_event *event) +{ +} + +static void pt_event_destroy(struct perf_event *event) +{ + pt_addr_filters_fini(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; + + if (pt_addr_filters_init(event)) { + x86_del_exclusive(x86_lbr_exclusive_pt); + return -ENOMEM; + } + + 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); +} + +int is_intel_pt_event(struct perf_event *event) +{ + return event->pmu == &pt_pmu.pmu; +} + +static __init int pt_init(void) +{ + int ret, cpu, prior_warn = 0; + + BUILD_BUG_ON(sizeof(struct topa) > PAGE_SIZE); + + if (!boot_cpu_has(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 (!intel_pt_validate_hw_cap(PT_CAP_topa_output)) { + pr_warn("ToPA output is not supported on this CPU\n"); + return -ENODEV; + } + + if (!intel_pt_validate_hw_cap(PT_CAP_topa_multiple_entries)) + pt_pmu.pmu.capabilities = PERF_PMU_CAP_AUX_NO_SG; + + 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.snapshot_aux = pt_event_snapshot_aux; + 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; + pt_pmu.pmu.addr_filters_sync = pt_event_addr_filters_sync; + pt_pmu.pmu.addr_filters_validate = pt_event_addr_filters_validate; + pt_pmu.pmu.nr_addr_filters = + intel_pt_validate_hw_cap(PT_CAP_num_address_ranges); + + ret = perf_pmu_register(&pt_pmu.pmu, "intel_pt", -1); + + return ret; +} +arch_initcall(pt_init); |