diff options
| -rw-r--r-- | drivers/perf/Kconfig | 11 | ||||
| -rw-r--r-- | drivers/perf/Makefile | 1 | ||||
| -rw-r--r-- | drivers/perf/arm_brbe.c | 805 | ||||
| -rw-r--r-- | drivers/perf/arm_brbe.h | 47 | ||||
| -rw-r--r-- | drivers/perf/arm_pmu.c | 16 | ||||
| -rw-r--r-- | drivers/perf/arm_pmuv3.c | 107 | ||||
| -rw-r--r-- | include/linux/perf/arm_pmu.h | 8 |
7 files changed, 990 insertions, 5 deletions
diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig index 278c929dc87a..a9188dec36fe 100644 --- a/drivers/perf/Kconfig +++ b/drivers/perf/Kconfig @@ -223,6 +223,17 @@ config ARM_SPE_PMU Extension, which provides periodic sampling of operations in the CPU pipeline and reports this via the perf AUX interface. +config ARM64_BRBE + bool "Enable support for branch stack sampling using FEAT_BRBE" + depends on ARM_PMUV3 && ARM64 + default y + help + Enable perf support for Branch Record Buffer Extension (BRBE) which + records all branches taken in an execution path. This supports some + branch types and privilege based filtering. It captures additional + relevant information such as cycle count, misprediction and branch + type, branch privilege level etc. + config ARM_DMC620_PMU tristate "Enable PMU support for the ARM DMC-620 memory controller" depends on (ARM64 && ACPI) || COMPILE_TEST diff --git a/drivers/perf/Makefile b/drivers/perf/Makefile index de71d2574857..192fc8b16204 100644 --- a/drivers/perf/Makefile +++ b/drivers/perf/Makefile @@ -23,6 +23,7 @@ obj-$(CONFIG_STARFIVE_STARLINK_PMU) += starfive_starlink_pmu.o obj-$(CONFIG_THUNDERX2_PMU) += thunderx2_pmu.o obj-$(CONFIG_XGENE_PMU) += xgene_pmu.o obj-$(CONFIG_ARM_SPE_PMU) += arm_spe_pmu.o +obj-$(CONFIG_ARM64_BRBE) += arm_brbe.o obj-$(CONFIG_ARM_DMC620_PMU) += arm_dmc620_pmu.o obj-$(CONFIG_MARVELL_CN10K_TAD_PMU) += marvell_cn10k_tad_pmu.o obj-$(CONFIG_MARVELL_CN10K_DDR_PMU) += marvell_cn10k_ddr_pmu.o diff --git a/drivers/perf/arm_brbe.c b/drivers/perf/arm_brbe.c new file mode 100644 index 000000000000..ba554e0c846c --- /dev/null +++ b/drivers/perf/arm_brbe.c @@ -0,0 +1,805 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Branch Record Buffer Extension Driver. + * + * Copyright (C) 2022-2025 ARM Limited + * + * Author: Anshuman Khandual <anshuman.khandual@arm.com> + */ +#include <linux/types.h> +#include <linux/bitmap.h> +#include <linux/perf/arm_pmu.h> +#include "arm_brbe.h" + +#define BRBFCR_EL1_BRANCH_FILTERS (BRBFCR_EL1_DIRECT | \ + BRBFCR_EL1_INDIRECT | \ + BRBFCR_EL1_RTN | \ + BRBFCR_EL1_INDCALL | \ + BRBFCR_EL1_DIRCALL | \ + BRBFCR_EL1_CONDDIR) + +/* + * BRBTS_EL1 is currently not used for branch stack implementation + * purpose but BRBCR_ELx.TS needs to have a valid value from all + * available options. BRBCR_ELx_TS_VIRTUAL is selected for this. + */ +#define BRBCR_ELx_DEFAULT_TS FIELD_PREP(BRBCR_ELx_TS_MASK, BRBCR_ELx_TS_VIRTUAL) + +/* + * BRBE Buffer Organization + * + * BRBE buffer is arranged as multiple banks of 32 branch record + * entries each. An individual branch record in a given bank could + * be accessed, after selecting the bank in BRBFCR_EL1.BANK and + * accessing the registers i.e [BRBSRC, BRBTGT, BRBINF] set with + * indices [0..31]. + * + * Bank 0 + * + * --------------------------------- ------ + * | 00 | BRBSRC | BRBTGT | BRBINF | | 00 | + * --------------------------------- ------ + * | 01 | BRBSRC | BRBTGT | BRBINF | | 01 | + * --------------------------------- ------ + * | .. | BRBSRC | BRBTGT | BRBINF | | .. | + * --------------------------------- ------ + * | 31 | BRBSRC | BRBTGT | BRBINF | | 31 | + * --------------------------------- ------ + * + * Bank 1 + * + * --------------------------------- ------ + * | 32 | BRBSRC | BRBTGT | BRBINF | | 00 | + * --------------------------------- ------ + * | 33 | BRBSRC | BRBTGT | BRBINF | | 01 | + * --------------------------------- ------ + * | .. | BRBSRC | BRBTGT | BRBINF | | .. | + * --------------------------------- ------ + * | 63 | BRBSRC | BRBTGT | BRBINF | | 31 | + * --------------------------------- ------ + */ +#define BRBE_BANK_MAX_ENTRIES 32 + +struct brbe_regset { + u64 brbsrc; + u64 brbtgt; + u64 brbinf; +}; + +#define PERF_BR_ARM64_MAX (PERF_BR_MAX + PERF_BR_NEW_MAX) + +struct brbe_hw_attr { + int brbe_version; + int brbe_cc; + int brbe_nr; + int brbe_format; +}; + +#define BRBE_REGN_CASE(n, case_macro) \ + case n: case_macro(n); break + +#define BRBE_REGN_SWITCH(x, case_macro) \ + do { \ + switch (x) { \ + BRBE_REGN_CASE(0, case_macro); \ + BRBE_REGN_CASE(1, case_macro); \ + BRBE_REGN_CASE(2, case_macro); \ + BRBE_REGN_CASE(3, case_macro); \ + BRBE_REGN_CASE(4, case_macro); \ + BRBE_REGN_CASE(5, case_macro); \ + BRBE_REGN_CASE(6, case_macro); \ + BRBE_REGN_CASE(7, case_macro); \ + BRBE_REGN_CASE(8, case_macro); \ + BRBE_REGN_CASE(9, case_macro); \ + BRBE_REGN_CASE(10, case_macro); \ + BRBE_REGN_CASE(11, case_macro); \ + BRBE_REGN_CASE(12, case_macro); \ + BRBE_REGN_CASE(13, case_macro); \ + BRBE_REGN_CASE(14, case_macro); \ + BRBE_REGN_CASE(15, case_macro); \ + BRBE_REGN_CASE(16, case_macro); \ + BRBE_REGN_CASE(17, case_macro); \ + BRBE_REGN_CASE(18, case_macro); \ + BRBE_REGN_CASE(19, case_macro); \ + BRBE_REGN_CASE(20, case_macro); \ + BRBE_REGN_CASE(21, case_macro); \ + BRBE_REGN_CASE(22, case_macro); \ + BRBE_REGN_CASE(23, case_macro); \ + BRBE_REGN_CASE(24, case_macro); \ + BRBE_REGN_CASE(25, case_macro); \ + BRBE_REGN_CASE(26, case_macro); \ + BRBE_REGN_CASE(27, case_macro); \ + BRBE_REGN_CASE(28, case_macro); \ + BRBE_REGN_CASE(29, case_macro); \ + BRBE_REGN_CASE(30, case_macro); \ + BRBE_REGN_CASE(31, case_macro); \ + default: WARN(1, "Invalid BRB* index %d\n", x); \ + } \ + } while (0) + +#define RETURN_READ_BRBSRCN(n) \ + return read_sysreg_s(SYS_BRBSRC_EL1(n)) +static inline u64 get_brbsrc_reg(int idx) +{ + BRBE_REGN_SWITCH(idx, RETURN_READ_BRBSRCN); + return 0; +} + +#define RETURN_READ_BRBTGTN(n) \ + return read_sysreg_s(SYS_BRBTGT_EL1(n)) +static u64 get_brbtgt_reg(int idx) +{ + BRBE_REGN_SWITCH(idx, RETURN_READ_BRBTGTN); + return 0; +} + +#define RETURN_READ_BRBINFN(n) \ + return read_sysreg_s(SYS_BRBINF_EL1(n)) +static u64 get_brbinf_reg(int idx) +{ + BRBE_REGN_SWITCH(idx, RETURN_READ_BRBINFN); + return 0; +} + +static u64 brbe_record_valid(u64 brbinf) +{ + return FIELD_GET(BRBINFx_EL1_VALID_MASK, brbinf); +} + +static bool brbe_invalid(u64 brbinf) +{ + return brbe_record_valid(brbinf) == BRBINFx_EL1_VALID_NONE; +} + +static bool brbe_record_is_complete(u64 brbinf) +{ + return brbe_record_valid(brbinf) == BRBINFx_EL1_VALID_FULL; +} + +static bool brbe_record_is_source_only(u64 brbinf) +{ + return brbe_record_valid(brbinf) == BRBINFx_EL1_VALID_SOURCE; +} + +static bool brbe_record_is_target_only(u64 brbinf) +{ + return brbe_record_valid(brbinf) == BRBINFx_EL1_VALID_TARGET; +} + +static int brbinf_get_in_tx(u64 brbinf) +{ + return FIELD_GET(BRBINFx_EL1_T_MASK, brbinf); +} + +static int brbinf_get_mispredict(u64 brbinf) +{ + return FIELD_GET(BRBINFx_EL1_MPRED_MASK, brbinf); +} + +static int brbinf_get_lastfailed(u64 brbinf) +{ + return FIELD_GET(BRBINFx_EL1_LASTFAILED_MASK, brbinf); +} + +static u16 brbinf_get_cycles(u64 brbinf) +{ + u32 exp, mant, cycles; + /* + * Captured cycle count is unknown and hence + * should not be passed on to userspace. + */ + if (brbinf & BRBINFx_EL1_CCU) + return 0; + + exp = FIELD_GET(BRBINFx_EL1_CC_EXP_MASK, brbinf); + mant = FIELD_GET(BRBINFx_EL1_CC_MANT_MASK, brbinf); + + if (!exp) + return mant; + + cycles = (mant | 0x100) << (exp - 1); + + return min(cycles, U16_MAX); +} + +static int brbinf_get_type(u64 brbinf) +{ + return FIELD_GET(BRBINFx_EL1_TYPE_MASK, brbinf); +} + +static int brbinf_get_el(u64 brbinf) +{ + return FIELD_GET(BRBINFx_EL1_EL_MASK, brbinf); +} + +void brbe_invalidate(void) +{ + /* Ensure all branches before this point are recorded */ + isb(); + asm volatile(BRB_IALL_INSN); + /* Ensure all branch records are invalidated after this point */ + isb(); +} + +static bool valid_brbe_nr(int brbe_nr) +{ + return brbe_nr == BRBIDR0_EL1_NUMREC_8 || + brbe_nr == BRBIDR0_EL1_NUMREC_16 || + brbe_nr == BRBIDR0_EL1_NUMREC_32 || + brbe_nr == BRBIDR0_EL1_NUMREC_64; +} + +static bool valid_brbe_cc(int brbe_cc) +{ + return brbe_cc == BRBIDR0_EL1_CC_20_BIT; +} + +static bool valid_brbe_format(int brbe_format) +{ + return brbe_format == BRBIDR0_EL1_FORMAT_FORMAT_0; +} + +static bool valid_brbidr(u64 brbidr) +{ + int brbe_format, brbe_cc, brbe_nr; + + brbe_format = FIELD_GET(BRBIDR0_EL1_FORMAT_MASK, brbidr); + brbe_cc = FIELD_GET(BRBIDR0_EL1_CC_MASK, brbidr); + brbe_nr = FIELD_GET(BRBIDR0_EL1_NUMREC_MASK, brbidr); + + return valid_brbe_format(brbe_format) && valid_brbe_cc(brbe_cc) && valid_brbe_nr(brbe_nr); +} + +static bool valid_brbe_version(int brbe_version) +{ + return brbe_version == ID_AA64DFR0_EL1_BRBE_IMP || + brbe_version == ID_AA64DFR0_EL1_BRBE_BRBE_V1P1; +} + +static void select_brbe_bank(int bank) +{ + u64 brbfcr; + + brbfcr = read_sysreg_s(SYS_BRBFCR_EL1); + brbfcr &= ~BRBFCR_EL1_BANK_MASK; + brbfcr |= SYS_FIELD_PREP(BRBFCR_EL1, BANK, bank); + write_sysreg_s(brbfcr, SYS_BRBFCR_EL1); + /* + * Arm ARM (DDI 0487K.a) D.18.4 rule PPBZP requires explicit sync + * between setting BANK and accessing branch records. + */ + isb(); +} + +static bool __read_brbe_regset(struct brbe_regset *entry, int idx) +{ + entry->brbinf = get_brbinf_reg(idx); + + if (brbe_invalid(entry->brbinf)) + return false; + + entry->brbsrc = get_brbsrc_reg(idx); + entry->brbtgt = get_brbtgt_reg(idx); + return true; +} + +/* + * Generic perf branch filters supported on BRBE + * + * New branch filters need to be evaluated whether they could be supported on + * BRBE. This ensures that such branch filters would not just be accepted, to + * fail silently. PERF_SAMPLE_BRANCH_HV is a special case that is selectively + * supported only on platforms where kernel is in hyp mode. + */ +#define BRBE_EXCLUDE_BRANCH_FILTERS (PERF_SAMPLE_BRANCH_ABORT_TX | \ + PERF_SAMPLE_BRANCH_IN_TX | \ + PERF_SAMPLE_BRANCH_NO_TX | \ + PERF_SAMPLE_BRANCH_CALL_STACK | \ + PERF_SAMPLE_BRANCH_COUNTERS) + +#define BRBE_ALLOWED_BRANCH_TYPES (PERF_SAMPLE_BRANCH_ANY | \ + PERF_SAMPLE_BRANCH_ANY_CALL | \ + PERF_SAMPLE_BRANCH_ANY_RETURN | \ + PERF_SAMPLE_BRANCH_IND_CALL | \ + PERF_SAMPLE_BRANCH_COND | \ + PERF_SAMPLE_BRANCH_IND_JUMP | \ + PERF_SAMPLE_BRANCH_CALL) + + +#define BRBE_ALLOWED_BRANCH_FILTERS (PERF_SAMPLE_BRANCH_USER | \ + PERF_SAMPLE_BRANCH_KERNEL | \ + PERF_SAMPLE_BRANCH_HV | \ + BRBE_ALLOWED_BRANCH_TYPES | \ + PERF_SAMPLE_BRANCH_NO_FLAGS | \ + PERF_SAMPLE_BRANCH_NO_CYCLES | \ + PERF_SAMPLE_BRANCH_TYPE_SAVE | \ + PERF_SAMPLE_BRANCH_HW_INDEX | \ + PERF_SAMPLE_BRANCH_PRIV_SAVE) + +#define BRBE_PERF_BRANCH_FILTERS (BRBE_ALLOWED_BRANCH_FILTERS | \ + BRBE_EXCLUDE_BRANCH_FILTERS) + +/* + * BRBE supports the following functional branch type filters while + * generating branch records. These branch filters can be enabled, + * either individually or as a group i.e ORing multiple filters + * with each other. + * + * BRBFCR_EL1_CONDDIR - Conditional direct branch + * BRBFCR_EL1_DIRCALL - Direct call + * BRBFCR_EL1_INDCALL - Indirect call + * BRBFCR_EL1_INDIRECT - Indirect branch + * BRBFCR_EL1_DIRECT - Direct branch + * BRBFCR_EL1_RTN - Subroutine return + */ +static u64 branch_type_to_brbfcr(int branch_type) +{ + u64 brbfcr = 0; + + if (branch_type & PERF_SAMPLE_BRANCH_ANY) { + brbfcr |= BRBFCR_EL1_BRANCH_FILTERS; + return brbfcr; + } + + if (branch_type & PERF_SAMPLE_BRANCH_ANY_CALL) { + brbfcr |= BRBFCR_EL1_INDCALL; + brbfcr |= BRBFCR_EL1_DIRCALL; + } + + if (branch_type & PERF_SAMPLE_BRANCH_ANY_RETURN) + brbfcr |= BRBFCR_EL1_RTN; + + if (branch_type & PERF_SAMPLE_BRANCH_IND_CALL) + brbfcr |= BRBFCR_EL1_INDCALL; + + if (branch_type & PERF_SAMPLE_BRANCH_COND) + brbfcr |= BRBFCR_EL1_CONDDIR; + + if (branch_type & PERF_SAMPLE_BRANCH_IND_JUMP) + brbfcr |= BRBFCR_EL1_INDIRECT; + + if (branch_type & PERF_SAMPLE_BRANCH_CALL) + brbfcr |= BRBFCR_EL1_DIRCALL; + + return brbfcr; +} + +/* + * BRBE supports the following privilege mode filters while generating + * branch records. + * + * BRBCR_ELx_E0BRE - EL0 branch records + * BRBCR_ELx_ExBRE - EL1/EL2 branch records + * + * BRBE also supports the following additional functional branch type + * filters while generating branch records. + * + * BRBCR_ELx_EXCEPTION - Exception + * BRBCR_ELx_ERTN - Exception return + */ +static u64 branch_type_to_brbcr(int branch_type) +{ + u64 brbcr = BRBCR_ELx_FZP | BRBCR_ELx_DEFAULT_TS; + + if (branch_type & PERF_SAMPLE_BRANCH_USER) + brbcr |= BRBCR_ELx_E0BRE; + + /* + * When running in the hyp mode, writing into BRBCR_EL1 + * actually writes into BRBCR_EL2 instead. Field E2BRE + * is also at the same position as E1BRE. + */ + if (branch_type & PERF_SAMPLE_BRANCH_KERNEL) + brbcr |= BRBCR_ELx_ExBRE; + + if (branch_type & PERF_SAMPLE_BRANCH_HV) { + if (is_kernel_in_hyp_mode()) + brbcr |= BRBCR_ELx_ExBRE; + } + + if (!(branch_type & PERF_SAMPLE_BRANCH_NO_CYCLES)) + brbcr |= BRBCR_ELx_CC; + + if (!(branch_type & PERF_SAMPLE_BRANCH_NO_FLAGS)) + brbcr |= BRBCR_ELx_MPRED; + + /* + * The exception and exception return branches could be + * captured, irrespective of the perf event's privilege. + * If the perf event does not have enough privilege for + * a given exception level, then addresses which falls + * under that exception level will be reported as zero + * for the captured branch record, creating source only + * or target only records. + */ + if (branch_type & PERF_SAMPLE_BRANCH_KERNEL) { + if (branch_type & PERF_SAMPLE_BRANCH_ANY) { + brbcr |= BRBCR_ELx_EXCEPTION; + brbcr |= BRBCR_ELx_ERTN; + } + + if (branch_type & PERF_SAMPLE_BRANCH_ANY_CALL) + brbcr |= BRBCR_ELx_EXCEPTION; + + if (branch_type & PERF_SAMPLE_BRANCH_ANY_RETURN) + brbcr |= BRBCR_ELx_ERTN; + } + return brbcr; +} + +bool brbe_branch_attr_valid(struct perf_event *event) +{ + u64 branch_type = event->attr.branch_sample_type; + + /* + * Ensure both perf branch filter allowed and exclude + * masks are always in sync with the generic perf ABI. + */ + BUILD_BUG_ON(BRBE_PERF_BRANCH_FILTERS != (PERF_SAMPLE_BRANCH_MAX - 1)); + + if (branch_type & BRBE_EXCLUDE_BRANCH_FILTERS) { + pr_debug("requested branch filter not supported 0x%llx\n", branch_type); + return false; + } + + /* Ensure at least 1 branch type is enabled */ + if (!(branch_type & BRBE_ALLOWED_BRANCH_TYPES)) { + pr_debug("no branch type enabled 0x%llx\n", branch_type); + return false; + } + + /* + * No branches are recorded in guests nor nVHE hypervisors, so + * excluding the host or both kernel and user is invalid. + * + * Ideally we'd just require exclude_guest and exclude_hv, but setting + * event filters with perf for kernel or user don't set exclude_guest. + * So effectively, exclude_guest and exclude_hv are ignored. + */ + if (event->attr.exclude_host || (event->attr.exclude_user && event->attr.exclude_kernel)) { + pr_debug("branch filter in hypervisor or guest only not supported 0x%llx\n", branch_type); + return false; + } + + event->hw.branch_reg.config = branch_type_to_brbfcr(event->attr.branch_sample_type); + event->hw.extra_reg.config = branch_type_to_brbcr(event->attr.branch_sample_type); + + return true; +} + +unsigned int brbe_num_branch_records(const struct arm_pmu *armpmu) +{ + return FIELD_GET(BRBIDR0_EL1_NUMREC_MASK, armpmu->reg_brbidr); +} + +void brbe_probe(struct arm_pmu *armpmu) +{ + u64 brbidr, aa64dfr0 = read_sysreg_s(SYS_ID_AA64DFR0_EL1); + u32 brbe; + + brbe = cpuid_feature_extract_unsigned_field(aa64dfr0, ID_AA64DFR0_EL1_BRBE_SHIFT); + if (!valid_brbe_version(brbe)) + return; + + brbidr = read_sysreg_s(SYS_BRBIDR0_EL1); + if (!valid_brbidr(brbidr)) + return; + + armpmu->reg_brbidr = brbidr; +} + +/* + * BRBE is assumed to be disabled/paused on entry + */ +void brbe_enable(const struct arm_pmu *arm_pmu) +{ + struct pmu_hw_events *cpuc = this_cpu_ptr(arm_pmu->hw_events); + u64 brbfcr = 0, brbcr = 0; + + /* + * Discard existing records to avoid a discontinuity, e.g. records + * missed during handling an overflow. + */ + brbe_invalidate(); + + /* + * Merge the permitted branch filters of all events. + */ + for (int i = 0; i < ARMPMU_MAX_HWEVENTS; i++) { + struct perf_event *event = cpuc->events[i]; + + if (event && has_branch_stack(event)) { + brbfcr |= event->hw.branch_reg.config; + brbcr |= event->hw.extra_reg.config; + } + } + + /* + * In VHE mode with MDCR_EL2.HPMN equal to PMCR_EL0.N, BRBCR_EL1.FZP + * controls freezing the branch records on counter overflow rather than + * BRBCR_EL2.FZP (which writes to BRBCR_EL1 are redirected to). + * The exception levels are enabled/disabled in BRBCR_EL2, so keep EL1 + * and EL0 recording disabled for guests. + * + * As BRBCR_EL1 CC and MPRED bits also need to match, use the same + * value for both registers just masking the exception levels. + */ + if (is_kernel_in_hyp_mode()) + write_sysreg_s(brbcr & ~(BRBCR_ELx_ExBRE | BRBCR_ELx_E0BRE), SYS_BRBCR_EL12); + write_sysreg_s(brbcr, SYS_BRBCR_EL1); + /* Ensure BRBCR_ELx settings take effect before unpausing */ + isb(); + + /* Finally write SYS_BRBFCR_EL to unpause BRBE */ + write_sysreg_s(brbfcr, SYS_BRBFCR_EL1); + /* Synchronization in PMCR write ensures ordering WRT PMU enabling */ +} + +void brbe_disable(void) +{ + /* + * No need for synchronization here as synchronization in PMCR write + * ensures ordering and in the interrupt handler this is a NOP as + * we're already paused. + */ + write_sysreg_s(BRBFCR_EL1_PAUSED, SYS_BRBFCR_EL1); + write_sysreg_s(0, SYS_BRBCR_EL1); +} + +static const int brbe_type_to_perf_type_map[BRBINFx_EL1_TYPE_DEBUG_EXIT + 1][2] = { + [BRBINFx_EL1_TYPE_DIRECT_UNCOND] = { PERF_BR_UNCOND, 0 }, + [BRBINFx_EL1_TYPE_INDIRECT] = { PERF_BR_IND, 0 }, + [BRBINFx_EL1_TYPE_DIRECT_LINK] = { PERF_BR_CALL, 0 }, + [BRBINFx_EL1_TYPE_INDIRECT_LINK] = { PERF_BR_IND_CALL, 0 }, + [BRBINFx_EL1_TYPE_RET] = { PERF_BR_RET, 0 }, + [BRBINFx_EL1_TYPE_DIRECT_COND] = { PERF_BR_COND, 0 }, + [BRBINFx_EL1_TYPE_CALL] = { PERF_BR_SYSCALL, 0 }, + [BRBINFx_EL1_TYPE_ERET] = { PERF_BR_ERET, 0 }, + [BRBINFx_EL1_TYPE_IRQ] = { PERF_BR_IRQ, 0 }, + [BRBINFx_EL1_TYPE_TRAP] = { PERF_BR_IRQ, 0 }, + [BRBINFx_EL1_TYPE_SERROR] = { PERF_BR_SERROR, 0 }, + [BRBINFx_EL1_TYPE_ALIGN_FAULT] = { PERF_BR_EXTEND_ABI, PERF_BR_NEW_FAULT_ALGN }, + [BRBINFx_EL1_TYPE_INSN_FAULT] = { PERF_BR_EXTEND_ABI, PERF_BR_NEW_FAULT_INST }, + [BRBINFx_EL1_TYPE_DATA_FAULT] = { PERF_BR_EXTEND_ABI, PERF_BR_NEW_FAULT_DATA }, +}; + +static void brbe_set_perf_entry_type(struct perf_branch_entry *entry, u64 brbinf) +{ + int brbe_type = brbinf_get_type(brbinf); + + if (brbe_type <= BRBINFx_EL1_TYPE_DEBUG_EXIT) { + const int *br_type = brbe_type_to_perf_type_map[brbe_type]; + + entry->type = br_type[0]; + entry->new_type = br_type[1]; + } +} + +static int brbinf_get_perf_priv(u64 brbinf) +{ + int brbe_el = brbinf_get_el(brbinf); + + switch (brbe_el) { + case BRBINFx_EL1_EL_EL0: + return PERF_BR_PRIV_USER; + case BRBINFx_EL1_EL_EL1: + return PERF_BR_PRIV_KERNEL; + case BRBINFx_EL1_EL_EL2: + if (is_kernel_in_hyp_mode()) + return PERF_BR_PRIV_KERNEL; + return PERF_BR_PRIV_HV; + default: + pr_warn_once("%d - unknown branch privilege captured\n", brbe_el); + return PERF_BR_PRIV_UNKNOWN; + } +} + +static bool perf_entry_from_brbe_regset(int index, struct perf_branch_entry *entry, + const struct perf_event *event) +{ + struct brbe_regset bregs; + u64 brbinf; + + if (!__read_brbe_regset(&bregs, index)) + return false; + + brbinf = bregs.brbinf; + perf_clear_branch_entry_bitfields(entry); + if (brbe_record_is_complete(brbinf)) { + entry->from = bregs.brbsrc; + entry->to = bregs.brbtgt; + } else if (brbe_record_is_source_only(brbinf)) { + entry->from = bregs.brbsrc; + entry->to = 0; + } else if (brbe_record_is_target_only(brbinf)) { + entry->from = 0; + entry->to = bregs.brbtgt; + } + + brbe_set_perf_entry_type(entry, brbinf); + + if (!branch_sample_no_cycles(event)) + entry->cycles = brbinf_get_cycles(brbinf); + + if (!branch_sample_no_flags(event)) { + /* Mispredict info is available for source only and complete branch records. */ + if (!brbe_record_is_target_only(brbinf)) { + entry->mispred = brbinf_get_mispredict(brbinf); + entry->predicted = !entry->mispred; + } + + /* + * Currently TME feature is neither implemented in any hardware + * nor it is being supported in the kernel. Just warn here once + * if TME related information shows up rather unexpectedly. + */ + if (brbinf_get_lastfailed(brbinf) || brbinf_get_in_tx(brbinf)) + pr_warn_once("Unknown transaction states\n"); + } + + /* + * Branch privilege level is available for target only and complete + * branch records. + */ + if (!brbe_record_is_source_only(brbinf)) + entry->priv = brbinf_get_perf_priv(brbinf); + + return true; +} + +#define PERF_BR_ARM64_ALL ( \ + BIT(PERF_BR_COND) | \ + BIT(PERF_BR_UNCOND) | \ + BIT(PERF_BR_IND) | \ + BIT(PERF_BR_CALL) | \ + BIT(PERF_BR_IND_CALL) | \ + BIT(PERF_BR_RET)) + +#define PERF_BR_ARM64_ALL_KERNEL ( \ + BIT(PERF_BR_SYSCALL) | \ + BIT(PERF_BR_IRQ) | \ + BIT(PERF_BR_SERROR) | \ + BIT(PERF_BR_MAX + PERF_BR_NEW_FAULT_ALGN) | \ + BIT(PERF_BR_MAX + PERF_BR_NEW_FAULT_DATA) | \ + BIT(PERF_BR_MAX + PERF_BR_NEW_FAULT_INST)) + +static void prepare_event_branch_type_mask(u64 branch_sample, + unsigned long *event_type_mask) +{ + if (branch_sample & PERF_SAMPLE_BRANCH_ANY) { + if (branch_sample & PERF_SAMPLE_BRANCH_KERNEL) + bitmap_from_u64(event_type_mask, + BIT(PERF_BR_ERET) | PERF_BR_ARM64_ALL | + PERF_BR_ARM64_ALL_KERNEL); + else + bitmap_from_u64(event_type_mask, PERF_BR_ARM64_ALL); + return; + } + + bitmap_zero(event_type_mask, PERF_BR_ARM64_MAX); + + if (branch_sample & PERF_SAMPLE_BRANCH_ANY_CALL) { + if (branch_sample & PERF_SAMPLE_BRANCH_KERNEL) + bitmap_from_u64(event_type_mask, PERF_BR_ARM64_ALL_KERNEL); + + set_bit(PERF_BR_CALL, event_type_mask); + set_bit(PERF_BR_IND_CALL, event_type_mask); + } + + if (branch_sample & PERF_SAMPLE_BRANCH_IND_JUMP) + set_bit(PERF_BR_IND, event_type_mask); + + if (branch_sample & PERF_SAMPLE_BRANCH_COND) + set_bit(PERF_BR_COND, event_type_mask); + + if (branch_sample & PERF_SAMPLE_BRANCH_CALL) + set_bit(PERF_BR_CALL, event_type_mask); + + if (branch_sample & PERF_SAMPLE_BRANCH_IND_CALL) + set_bit(PERF_BR_IND_CALL, event_type_mask); + + if (branch_sample & PERF_SAMPLE_BRANCH_ANY_RETURN) { + set_bit(PERF_BR_RET, event_type_mask); + + if (branch_sample & PERF_SAMPLE_BRANCH_KERNEL) + set_bit(PERF_BR_ERET, event_type_mask); + } +} + +/* + * BRBE is configured with an OR of permissions from all events, so there may + * be events which have to be dropped or events where just the source or target + * address has to be zeroed. + */ +static bool filter_branch_privilege(struct perf_branch_entry *entry, u64 branch_sample_type) +{ + bool from_user = access_ok((void __user *)(unsigned long)entry->from, 4); + bool to_user = access_ok((void __user *)(unsigned long)entry->to, 4); + bool exclude_kernel = !((branch_sample_type & PERF_SAMPLE_BRANCH_KERNEL) || + (is_kernel_in_hyp_mode() && (branch_sample_type & PERF_SAMPLE_BRANCH_HV))); + + /* We can only have a half record if permissions have not been expanded */ + if (!entry->from || !entry->to) + return true; + + /* + * If record is within a single exception level, just need to either + * drop or keep the entire record. + */ + if (from_user == to_user) + return ((entry->priv == PERF_BR_PRIV_KERNEL) && !exclude_kernel) || + ((entry->priv == PERF_BR_PRIV_USER) && + (branch_sample_type & PERF_SAMPLE_BRANCH_USER)); + + /* + * Record is across exception levels, mask addresses for the exception + * level we're not capturing. + */ + if (!(branch_sample_type & PERF_SAMPLE_BRANCH_USER)) { + if (from_user) + entry->from = 0; + if (to_user) + entry->to = 0; + } + + if (exclude_kernel) { + if (!from_user) + entry->from = 0; + if (!to_user) + entry->to = 0; + } + + return true; +} + +static bool filter_branch_type(struct perf_branch_entry *entry, + const unsigned long *event_type_mask) +{ + if (entry->type == PERF_BR_EXTEND_ABI) + return test_bit(PERF_BR_MAX + entry->new_type, event_type_mask); + else + return test_bit(entry->type, event_type_mask); +} + +static bool filter_branch_record(struct perf_branch_entry *entry, + u64 branch_sample, + const unsigned long *event_type_mask) +{ + return filter_branch_type(entry, event_type_mask) && + filter_branch_privilege(entry, branch_sample); +} + +void brbe_read_filtered_entries(struct perf_branch_stack *branch_stack, + const struct perf_event *event) +{ + struct arm_pmu *cpu_pmu = to_arm_pmu(event->pmu); + int nr_hw = brbe_num_branch_records(cpu_pmu); + int nr_banks = DIV_ROUND_UP(nr_hw, BRBE_BANK_MAX_ENTRIES); + int nr_filtered = 0; + u64 branch_sample_type = event->attr.branch_sample_type; + DECLARE_BITMAP(event_type_mask, PERF_BR_ARM64_MAX); + + prepare_event_branch_type_mask(branch_sample_type, event_type_mask); + + for (int bank = 0; bank < nr_banks; bank++) { + int nr_remaining = nr_hw - (bank * BRBE_BANK_MAX_ENTRIES); + int nr_this_bank = min(nr_remaining, BRBE_BANK_MAX_ENTRIES); + + select_brbe_bank(bank); + + for (int i = 0; i < nr_this_bank; i++) { + struct perf_branch_entry *pbe = &branch_stack->entries[nr_filtered]; + + if (!perf_entry_from_brbe_regset(i, pbe, event)) + goto done; + + if (!filter_branch_record(pbe, branch_sample_type, event_type_mask)) + continue; + + nr_filtered++; + } + } + +done: + branch_stack->nr = nr_filtered; +} diff --git a/drivers/perf/arm_brbe.h b/drivers/perf/arm_brbe.h new file mode 100644 index 000000000000..b7c7d8796c86 --- /dev/null +++ b/drivers/perf/arm_brbe.h @@ -0,0 +1,47 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Branch Record Buffer Extension Helpers. + * + * Copyright (C) 2022-2025 ARM Limited + * + * Author: Anshuman Khandual <anshuman.khandual@arm.com> + */ + +struct arm_pmu; +struct perf_branch_stack; +struct perf_event; + +#ifdef CONFIG_ARM64_BRBE +void brbe_probe(struct arm_pmu *arm_pmu); +unsigned int brbe_num_branch_records(const struct arm_pmu *armpmu); +void brbe_invalidate(void); + +void brbe_enable(const struct arm_pmu *arm_pmu); +void brbe_disable(void); + +bool brbe_branch_attr_valid(struct perf_event *event); +void brbe_read_filtered_entries(struct perf_branch_stack *branch_stack, + const struct perf_event *event); +#else +static inline void brbe_probe(struct arm_pmu *arm_pmu) { } +static inline unsigned int brbe_num_branch_records(const struct arm_pmu *armpmu) +{ + return 0; +} + +static inline void brbe_invalidate(void) { } + +static inline void brbe_enable(const struct arm_pmu *arm_pmu) { }; +static inline void brbe_disable(void) { }; + +static inline bool brbe_branch_attr_valid(struct perf_event *event) +{ + WARN_ON_ONCE(!has_branch_stack(event)); + return false; +} + +static void brbe_read_filtered_entries(struct perf_branch_stack *branch_stack, + const struct perf_event *event) +{ +} +#endif diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c index 2f33e69a8caf..5c310e803dd7 100644 --- a/drivers/perf/arm_pmu.c +++ b/drivers/perf/arm_pmu.c @@ -99,7 +99,7 @@ static const struct pmu_irq_ops percpu_pmunmi_ops = { .free_pmuirq = armpmu_free_percpu_pmunmi }; -static DEFINE_PER_CPU(struct arm_pmu *, cpu_armpmu); +DEFINE_PER_CPU(struct arm_pmu *, cpu_armpmu); static DEFINE_PER_CPU(int, cpu_irq); static DEFINE_PER_CPU(const struct pmu_irq_ops *, cpu_irq_ops); @@ -318,6 +318,12 @@ armpmu_del(struct perf_event *event, int flags) int idx = hwc->idx; armpmu_stop(event, PERF_EF_UPDATE); + + if (has_branch_stack(event)) { + hw_events->branch_users--; + perf_sched_cb_dec(event->pmu); + } + hw_events->events[idx] = NULL; armpmu->clear_event_idx(hw_events, event); perf_event_update_userpage(event); @@ -345,6 +351,11 @@ armpmu_add(struct perf_event *event, int flags) /* The newly-allocated counter should be empty */ WARN_ON_ONCE(hw_events->events[idx]); + if (has_branch_stack(event)) { + hw_events->branch_users++; + perf_sched_cb_inc(event->pmu); + } + event->hw.idx = idx; hw_events->events[idx] = event; @@ -509,8 +520,7 @@ static int armpmu_event_init(struct perf_event *event) !cpumask_test_cpu(event->cpu, &armpmu->supported_cpus)) return -ENOENT; - /* does not support taken branch sampling */ - if (has_branch_stack(event)) + if (has_branch_stack(event) && !armpmu->reg_brbidr) return -EOPNOTSUPP; return __hw_perf_event_init(event); diff --git a/drivers/perf/arm_pmuv3.c b/drivers/perf/arm_pmuv3.c index 3db9f4ed17e8..f6d7bab5d555 100644 --- a/drivers/perf/arm_pmuv3.c +++ b/drivers/perf/arm_pmuv3.c @@ -25,6 +25,8 @@ #include <linux/smp.h> #include <linux/nmi.h> +#include "arm_brbe.h" + /* ARMv8 Cortex-A53 specific event types. */ #define ARMV8_A53_PERFCTR_PREF_LINEFILL 0xC2 @@ -438,7 +440,19 @@ static ssize_t threshold_max_show(struct device *dev, static DEVICE_ATTR_RO(threshold_max); +static ssize_t branches_show(struct device *dev, + struct device_attribute *attr, char *page) +{ + struct pmu *pmu = dev_get_drvdata(dev); + struct arm_pmu *cpu_pmu = container_of(pmu, struct arm_pmu, pmu); + + return sysfs_emit(page, "%d\n", brbe_num_branch_records(cpu_pmu)); +} + +static DEVICE_ATTR_RO(branches); + static struct attribute *armv8_pmuv3_caps_attrs[] = { + &dev_attr_branches.attr, &dev_attr_slots.attr, &dev_attr_bus_slots.attr, &dev_attr_bus_width.attr, @@ -446,9 +460,22 @@ static struct attribute *armv8_pmuv3_caps_attrs[] = { NULL, }; +static umode_t caps_is_visible(struct kobject *kobj, struct attribute *attr, int i) +{ + struct device *dev = kobj_to_dev(kobj); + struct pmu *pmu = dev_get_drvdata(dev); + struct arm_pmu *cpu_pmu = container_of(pmu, struct arm_pmu, pmu); + + if (i == 0) + return brbe_num_branch_records(cpu_pmu) ? attr->mode : 0; + + return attr->mode; +} + static const struct attribute_group armv8_pmuv3_caps_attr_group = { .name = "caps", .attrs = armv8_pmuv3_caps_attrs, + .is_visible = caps_is_visible, }; /* @@ -809,6 +836,7 @@ static void armv8pmu_disable_event(struct perf_event *event) static void armv8pmu_start(struct arm_pmu *cpu_pmu) { struct perf_event_context *ctx; + struct pmu_hw_events *hw_events = this_cpu_ptr(cpu_pmu->hw_events); int nr_user = 0; ctx = perf_cpu_task_ctx(); @@ -822,16 +850,34 @@ static void armv8pmu_start(struct arm_pmu *cpu_pmu) kvm_vcpu_pmu_resync_el0(); + if (hw_events->branch_users) + brbe_enable(cpu_pmu); + /* Enable all counters */ armv8pmu_pmcr_write(armv8pmu_pmcr_read() | ARMV8_PMU_PMCR_E); } static void armv8pmu_stop(struct arm_pmu *cpu_pmu) { + struct pmu_hw_events *hw_events = this_cpu_ptr(cpu_pmu->hw_events); + + if (hw_events->branch_users) + brbe_disable(); + /* Disable all counters */ armv8pmu_pmcr_write(armv8pmu_pmcr_read() & ~ARMV8_PMU_PMCR_E); } +static void read_branch_records(struct pmu_hw_events *cpuc, + struct perf_event *event, + struct perf_sample_data *data) +{ + struct perf_branch_stack *branch_stack = cpuc->branch_stack; + + brbe_read_filtered_entries(branch_stack, event); + perf_sample_save_brstack(data, event, branch_stack, NULL); +} + static irqreturn_t armv8pmu_handle_irq(struct arm_pmu *cpu_pmu) { u64 pmovsr; @@ -882,6 +928,9 @@ static irqreturn_t armv8pmu_handle_irq(struct arm_pmu *cpu_pmu) if (!armpmu_event_set_period(event)) continue; + if (has_branch_stack(event)) + read_branch_records(cpuc, event, &data); + /* * Perf event overflow will queue the processing of the event as * an irq_work which will be taken care of in the handling of @@ -938,7 +987,7 @@ static int armv8pmu_get_event_idx(struct pmu_hw_events *cpuc, /* Always prefer to place a cycle counter into the cycle counter. */ if ((evtype == ARMV8_PMUV3_PERFCTR_CPU_CYCLES) && - !armv8pmu_event_get_threshold(&event->attr)) { + !armv8pmu_event_get_threshold(&event->attr) && !has_branch_stack(event)) { if (!test_and_set_bit(ARMV8_PMU_CYCLE_IDX, cpuc->used_mask)) return ARMV8_PMU_CYCLE_IDX; else if (armv8pmu_event_is_64bit(event) && @@ -987,6 +1036,19 @@ static int armv8pmu_user_event_idx(struct perf_event *event) return event->hw.idx + 1; } +static void armv8pmu_sched_task(struct perf_event_pmu_context *pmu_ctx, + struct task_struct *task, bool sched_in) +{ + struct arm_pmu *armpmu = *this_cpu_ptr(&cpu_armpmu); + struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events); + + if (!hw_events->branch_users) + return; + + if (sched_in) + brbe_invalidate(); +} + /* * Add an event filter to a given event. */ @@ -1004,6 +1066,13 @@ static int armv8pmu_set_event_filter(struct hw_perf_event *event, return -EOPNOTSUPP; } + if (has_branch_stack(perf_event)) { + if (!brbe_num_branch_records(cpu_pmu) || !brbe_branch_attr_valid(perf_event)) + return -EOPNOTSUPP; + + perf_event->attach_state |= PERF_ATTACH_SCHED_CB; + } + /* * If we're running in hyp mode, then we *are* the hypervisor. * Therefore we ignore exclude_hv in this configuration, since @@ -1070,6 +1139,11 @@ static void armv8pmu_reset(void *info) /* Clear the counters we flip at guest entry/exit */ kvm_clr_pmu_events(mask); + if (brbe_num_branch_records(cpu_pmu)) { + brbe_disable(); + brbe_invalidate(); + } + /* * Initialize & Reset PMNC. Request overflow interrupt for * 64 bit cycle counter but cheat in armv8pmu_write_counter(). @@ -1238,6 +1312,25 @@ static void __armv8pmu_probe_pmu(void *info) cpu_pmu->reg_pmmir = read_pmmir(); else cpu_pmu->reg_pmmir = 0; + + brbe_probe(cpu_pmu); +} + +static int branch_records_alloc(struct arm_pmu *armpmu) +{ + size_t size = struct_size_t(struct perf_branch_stack, entries, + brbe_num_branch_records(armpmu)); + int cpu; + + for_each_cpu(cpu, &armpmu->supported_cpus) { + struct pmu_hw_events *events_cpu; + + events_cpu = per_cpu_ptr(armpmu->hw_events, cpu); + events_cpu->branch_stack = kmalloc(size, GFP_KERNEL); + if (!events_cpu->branch_stack) + return -ENOMEM; + } + return 0; } static int armv8pmu_probe_pmu(struct arm_pmu *cpu_pmu) @@ -1254,7 +1347,15 @@ static int armv8pmu_probe_pmu(struct arm_pmu *cpu_pmu) if (ret) return ret; - return probe.present ? 0 : -ENODEV; + if (!probe.present) + return -ENODEV; + + if (brbe_num_branch_records(cpu_pmu)) { + ret = branch_records_alloc(cpu_pmu); + if (ret) + return ret; + } + return 0; } static void armv8pmu_disable_user_access_ipi(void *unused) @@ -1313,6 +1414,8 @@ static int armv8_pmu_init(struct arm_pmu *cpu_pmu, char *name, cpu_pmu->set_event_filter = armv8pmu_set_event_filter; cpu_pmu->pmu.event_idx = armv8pmu_user_event_idx; + if (brbe_num_branch_records(cpu_pmu)) + cpu_pmu->pmu.sched_task = armv8pmu_sched_task; cpu_pmu->name = name; cpu_pmu->map_event = map_event; diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h index 6dc5e0cd76ca..93c9a26492fc 100644 --- a/include/linux/perf/arm_pmu.h +++ b/include/linux/perf/arm_pmu.h @@ -70,6 +70,11 @@ struct pmu_hw_events { struct arm_pmu *percpu_pmu; int irq; + + struct perf_branch_stack *branch_stack; + + /* Active events requesting branch records */ + unsigned int branch_users; }; enum armpmu_attr_groups { @@ -115,6 +120,7 @@ struct arm_pmu { /* PMUv3 only */ int pmuver; u64 reg_pmmir; + u64 reg_brbidr; #define ARMV8_PMUV3_MAX_COMMON_EVENTS 0x40 DECLARE_BITMAP(pmceid_bitmap, ARMV8_PMUV3_MAX_COMMON_EVENTS); #define ARMV8_PMUV3_EXT_COMMON_EVENT_BASE 0x4000 @@ -126,6 +132,8 @@ struct arm_pmu { #define to_arm_pmu(p) (container_of(p, struct arm_pmu, pmu)) +DECLARE_PER_CPU(struct arm_pmu *, cpu_armpmu); + u64 armpmu_event_update(struct perf_event *event); int armpmu_event_set_period(struct perf_event *event); |