@@ -19056,6 +19056,7 @@ M: Atish Patra <atishp@atishpatra.org>
R: Anup Patel <anup@brainfault.org>
L: linux-riscv@lists.infradead.org
S: Supported
+F: drivers/perf/riscv_ctr.c
F: drivers/perf/riscv_pmu_common.c
F: drivers/perf/riscv_pmu_dev.c
F: drivers/perf/riscv_pmu_legacy.c
@@ -110,6 +110,17 @@ config ANDES_CUSTOM_PMU
If you don't know what to do here, say "Y".
+config RISCV_CTR
+ bool "Enable support for Control Transfer Records (CTR)"
+ depends on PERF_EVENTS && RISCV_PMU
+ default y
+ help
+ Enable support for Control Transfer Records (CTR) which
+ allows recording branches, Jumps, Calls, returns etc taken in an
+ execution path. This also supports privilege based filtering. It
+ captures additional relevant information such as cycle count,
+ branch misprediction etc.
+
config ARM_PMU_ACPI
depends on ARM_PMU && ACPI
def_bool y
@@ -16,6 +16,7 @@ obj-$(CONFIG_RISCV_PMU_COMMON) += riscv_pmu_common.o
obj-$(CONFIG_RISCV_PMU_LEGACY) += riscv_pmu_legacy.o
obj-$(CONFIG_RISCV_PMU) += riscv_pmu_dev.o
obj-$(CONFIG_STARFIVE_STARLINK_PMU) += starfive_starlink_pmu.o
+obj-$(CONFIG_RISCV_CTR) += riscv_ctr.o
obj-$(CONFIG_THUNDERX2_PMU) += thunderx2_pmu.o
obj-$(CONFIG_XGENE_PMU) += xgene_pmu.o
obj-$(CONFIG_ARM_SPE_PMU) += arm_spe_pmu.o
new file mode 100644
@@ -0,0 +1,469 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Control transfer records extension Helpers.
+ *
+ * Copyright (C) 2024 Rivos Inc.
+ *
+ * Author: Rajnesh Kanwal <rkanwal@rivosinc.com>
+ */
+
+#define pr_fmt(fmt) "CTR: " fmt
+
+#include <linux/bitfield.h>
+#include <linux/printk.h>
+#include <linux/types.h>
+#include <linux/perf_event.h>
+#include <linux/perf/riscv_pmu.h>
+#include <linux/cpufeature.h>
+#include <asm/hwcap.h>
+#include <asm/csr_ind.h>
+#include <asm/csr.h>
+
+#define CTR_BRANCH_FILTERS_INH (CTRCTL_EXCINH | \
+ CTRCTL_INTRINH | \
+ CTRCTL_TRETINH | \
+ CTRCTL_TKBRINH | \
+ CTRCTL_INDCALL_INH | \
+ CTRCTL_DIRCALL_INH | \
+ CTRCTL_INDJUMP_INH | \
+ CTRCTL_DIRJUMP_INH | \
+ CTRCTL_CORSWAP_INH | \
+ CTRCTL_RET_INH | \
+ CTRCTL_INDOJUMP_INH | \
+ CTRCTL_DIROJUMP_INH)
+
+#define CTR_BRANCH_ENABLE_BITS (CTRCTL_KERNEL_ENABLE | CTRCTL_U_ENABLE)
+
+/* Branch filters not-supported by CTR extension. */
+#define CTR_EXCLUDE_BRANCH_FILTERS (PERF_SAMPLE_BRANCH_ABORT_TX | \
+ PERF_SAMPLE_BRANCH_IN_TX | \
+ PERF_SAMPLE_BRANCH_PRIV_SAVE | \
+ PERF_SAMPLE_BRANCH_NO_TX | \
+ PERF_SAMPLE_BRANCH_COUNTERS)
+
+/* Branch filters supported by CTR extension. */
+#define CTR_ALLOWED_BRANCH_FILTERS (PERF_SAMPLE_BRANCH_USER | \
+ PERF_SAMPLE_BRANCH_KERNEL | \
+ PERF_SAMPLE_BRANCH_HV | \
+ 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_HW_INDEX | \
+ PERF_SAMPLE_BRANCH_NO_FLAGS | \
+ PERF_SAMPLE_BRANCH_NO_CYCLES | \
+ PERF_SAMPLE_BRANCH_CALL_STACK | \
+ PERF_SAMPLE_BRANCH_CALL | \
+ PERF_SAMPLE_BRANCH_TYPE_SAVE)
+
+#define CTR_PERF_BRANCH_FILTERS (CTR_ALLOWED_BRANCH_FILTERS | \
+ CTR_EXCLUDE_BRANCH_FILTERS)
+
+static u64 allowed_filters __read_mostly;
+
+struct ctr_regset {
+ unsigned long src;
+ unsigned long target;
+ unsigned long ctr_data;
+};
+
+static inline u64 get_ctr_src_reg(unsigned int ctr_idx)
+{
+ return csr_ind_read(CSR_IREG, CTR_ENTRIES_FIRST, ctr_idx);
+}
+
+static inline u64 get_ctr_tgt_reg(unsigned int ctr_idx)
+{
+ return csr_ind_read(CSR_IREG2, CTR_ENTRIES_FIRST, ctr_idx);
+}
+
+static inline u64 get_ctr_data_reg(unsigned int ctr_idx)
+{
+ return csr_ind_read(CSR_IREG3, CTR_ENTRIES_FIRST, ctr_idx);
+}
+
+static inline bool ctr_record_valid(u64 ctr_src)
+{
+ return !!FIELD_GET(CTRSOURCE_VALID, ctr_src);
+}
+
+static inline int ctr_get_mispredict(u64 ctr_target)
+{
+ return FIELD_GET(CTRTARGET_MISP, ctr_target);
+}
+
+static inline unsigned int ctr_get_cycles(u64 ctr_data)
+{
+ const unsigned int cce = FIELD_GET(CTRDATA_CCE_MASK, ctr_data);
+ const unsigned int ccm = FIELD_GET(CTRDATA_CCM_MASK, ctr_data);
+
+ if (ctr_data & CTRDATA_CCV)
+ return 0;
+
+ /* Formula to calculate cycles from spec: (2^12 + CCM) << CCE-1 */
+ if (cce > 0)
+ return (4096 + ccm) << (cce - 1);
+
+ return FIELD_GET(CTRDATA_CCM_MASK, ctr_data);
+}
+
+static inline unsigned int ctr_get_type(u64 ctr_data)
+{
+ return FIELD_GET(CTRDATA_TYPE_MASK, ctr_data);
+}
+
+static inline unsigned int ctr_get_depth(u64 ctr_depth)
+{
+ /* Depth table from CTR Spec: 2.4 sctrdepth.
+ *
+ * sctrdepth.depth Depth
+ * 000 - 16
+ * 001 - 32
+ * 010 - 64
+ * 011 - 128
+ * 100 - 256
+ *
+ * Depth = 16 * 2 ^ (ctrdepth.depth)
+ * or
+ * Depth = 16 << ctrdepth.depth.
+ */
+ return 16 << FIELD_GET(SCTRDEPTH_MASK, ctr_depth);
+}
+
+/* Reads CTR entry at idx and stores it in entry struct. */
+static bool capture_ctr_regset(struct ctr_regset *entry, unsigned int idx)
+{
+ entry->src = get_ctr_src_reg(idx);
+
+ if (!ctr_record_valid(entry->src))
+ return false;
+
+ entry->src = entry->src & (~CTRSOURCE_VALID);
+ entry->target = get_ctr_tgt_reg(idx);
+ entry->ctr_data = get_ctr_data_reg(idx);
+
+ return true;
+}
+
+static u64 branch_type_to_ctr(int branch_type)
+{
+ u64 config = CTR_BRANCH_FILTERS_INH | CTRCTL_LCOFIFRZ;
+
+ if (branch_type & PERF_SAMPLE_BRANCH_USER)
+ config |= CTRCTL_U_ENABLE;
+
+ if (branch_type & PERF_SAMPLE_BRANCH_KERNEL)
+ config |= CTRCTL_KERNEL_ENABLE;
+
+ if (branch_type & PERF_SAMPLE_BRANCH_HV) {
+ if (riscv_isa_extension_available(NULL, h))
+ config |= CTRCTL_KERNEL_ENABLE;
+ }
+
+ if (branch_type & PERF_SAMPLE_BRANCH_ANY) {
+ config &= ~CTR_BRANCH_FILTERS_INH;
+ return config;
+ }
+
+ if (branch_type & PERF_SAMPLE_BRANCH_ANY_CALL) {
+ config &= ~CTRCTL_INDCALL_INH;
+ config &= ~CTRCTL_DIRCALL_INH;
+ config &= ~CTRCTL_EXCINH;
+ config &= ~CTRCTL_INTRINH;
+ }
+
+ if (branch_type & PERF_SAMPLE_BRANCH_ANY_RETURN)
+ config &= ~(CTRCTL_RET_INH | CTRCTL_TRETINH);
+
+ if (branch_type & PERF_SAMPLE_BRANCH_IND_CALL)
+ config &= ~CTRCTL_INDCALL_INH;
+
+ if (branch_type & PERF_SAMPLE_BRANCH_COND)
+ config &= ~CTRCTL_TKBRINH;
+
+ if (branch_type & PERF_SAMPLE_BRANCH_CALL_STACK) {
+ config &= ~(CTRCTL_INDCALL_INH | CTRCTL_DIRCALL_INH |
+ CTRCTL_RET_INH);
+ config |= CTRCTL_RASEMU;
+ }
+
+ if (branch_type & PERF_SAMPLE_BRANCH_IND_JUMP) {
+ config &= ~CTRCTL_INDJUMP_INH;
+ config &= ~CTRCTL_INDOJUMP_INH;
+ }
+
+ if (branch_type & PERF_SAMPLE_BRANCH_CALL)
+ config &= ~CTRCTL_DIRCALL_INH;
+
+ return config;
+}
+
+static const int ctr_perf_map[] = {
+ [CTRDATA_TYPE_NONE] = PERF_BR_UNKNOWN,
+ [CTRDATA_TYPE_EXCEPTION] = PERF_BR_SYSCALL,
+ [CTRDATA_TYPE_INTERRUPT] = PERF_BR_IRQ,
+ [CTRDATA_TYPE_TRAP_RET] = PERF_BR_ERET,
+ [CTRDATA_TYPE_NONTAKEN_BRANCH] = PERF_BR_COND,
+ [CTRDATA_TYPE_TAKEN_BRANCH] = PERF_BR_COND,
+ [CTRDATA_TYPE_RESERVED_6] = PERF_BR_UNKNOWN,
+ [CTRDATA_TYPE_RESERVED_7] = PERF_BR_UNKNOWN,
+ [CTRDATA_TYPE_INDIRECT_CALL] = PERF_BR_IND_CALL,
+ [CTRDATA_TYPE_DIRECT_CALL] = PERF_BR_CALL,
+ [CTRDATA_TYPE_INDIRECT_JUMP] = PERF_BR_UNCOND,
+ [CTRDATA_TYPE_DIRECT_JUMP] = PERF_BR_UNKNOWN,
+ [CTRDATA_TYPE_CO_ROUTINE_SWAP] = PERF_BR_UNKNOWN,
+ [CTRDATA_TYPE_RETURN] = PERF_BR_RET,
+ [CTRDATA_TYPE_OTHER_INDIRECT_JUMP] = PERF_BR_IND,
+ [CTRDATA_TYPE_OTHER_DIRECT_JUMP] = PERF_BR_UNKNOWN,
+};
+
+static void ctr_set_perf_entry_type(struct perf_branch_entry *entry,
+ u64 ctr_data)
+{
+ int ctr_type = ctr_get_type(ctr_data);
+
+ entry->type = ctr_perf_map[ctr_type];
+ if (entry->type == PERF_BR_UNKNOWN)
+ pr_warn("%d - unknown branch type captured\n", ctr_type);
+}
+
+static void capture_ctr_flags(struct perf_branch_entry *entry,
+ struct perf_event *event, u64 ctr_data,
+ u64 ctr_target)
+{
+ if (branch_sample_type(event))
+ ctr_set_perf_entry_type(entry, ctr_data);
+
+ if (!branch_sample_no_cycles(event))
+ entry->cycles = ctr_get_cycles(ctr_data);
+
+ if (!branch_sample_no_flags(event)) {
+ entry->abort = 0;
+ entry->mispred = ctr_get_mispredict(ctr_target);
+ entry->predicted = !entry->mispred;
+ }
+
+ if (branch_sample_priv(event))
+ entry->priv = PERF_BR_PRIV_UNKNOWN;
+}
+
+
+static void ctr_regset_to_branch_entry(struct cpu_hw_events *cpuc,
+ struct perf_event *event,
+ struct ctr_regset *regset,
+ unsigned int idx)
+{
+ struct perf_branch_entry *entry = &cpuc->branches->branch_entries[idx];
+
+ perf_clear_branch_entry_bitfields(entry);
+ entry->from = regset->src;
+ entry->to = regset->target & (~CTRTARGET_MISP);
+ capture_ctr_flags(entry, event, regset->ctr_data, regset->target);
+}
+
+static void ctr_read_entries(struct cpu_hw_events *cpuc,
+ struct perf_event *event,
+ unsigned int depth)
+{
+ struct ctr_regset entry = {};
+ u64 ctr_ctl;
+ int i;
+
+ ctr_ctl = csr_read_clear(CSR_CTRCTL, CTR_BRANCH_ENABLE_BITS);
+
+ for (i = 0; i < depth; i++) {
+ if (!capture_ctr_regset(&entry, i))
+ break;
+
+ ctr_regset_to_branch_entry(cpuc, event, &entry, i);
+ }
+
+ csr_set(CSR_CTRCTL, ctr_ctl & CTR_BRANCH_ENABLE_BITS);
+
+ cpuc->branches->branch_stack.nr = i;
+ cpuc->branches->branch_stack.hw_idx = 0;
+}
+
+bool riscv_pmu_ctr_valid(struct perf_event *event)
+{
+ u64 branch_type = event->attr.branch_sample_type;
+
+ if (branch_type & ~allowed_filters) {
+ pr_debug_once("Requested branch filters not supported 0x%llx\n",
+ branch_type & ~allowed_filters);
+ return false;
+ }
+
+ return true;
+}
+
+void riscv_pmu_ctr_consume(struct cpu_hw_events *cpuc, struct perf_event *event)
+{
+ unsigned int depth = to_riscv_pmu(event->pmu)->ctr_depth;
+
+ ctr_read_entries(cpuc, event, depth);
+
+ /* Clear frozen bit. */
+ csr_clear(CSR_SCTRSTATUS, SCTRSTATUS_FROZEN);
+}
+
+static void riscv_pmu_ctr_clear(void)
+{
+ /* FIXME: Replace with sctrclr instruction once support is merged
+ * into toolchain.
+ */
+ asm volatile(".4byte 0x10400073\n" ::: "memory");
+ csr_write(CSR_SCTRSTATUS, 0);
+}
+
+/*
+ * On context switch in, we need to make sure no samples from previous user
+ * are left in the CTR.
+ *
+ * On ctxswin, sched_in = true, called after the PMU has started
+ * On ctxswout, sched_in = false, called before the PMU is stopped
+ */
+void riscv_pmu_ctr_sched_task(struct perf_event_pmu_context *pmu_ctx,
+ bool sched_in)
+{
+ struct riscv_pmu *rvpmu = to_riscv_pmu(pmu_ctx->pmu);
+ struct cpu_hw_events *cpuc = this_cpu_ptr(rvpmu->hw_events);
+
+ if (cpuc->ctr_users && sched_in)
+ riscv_pmu_ctr_clear();
+}
+
+void riscv_pmu_ctr_enable(struct perf_event *event)
+{
+ struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);
+ struct cpu_hw_events *cpuc = this_cpu_ptr(rvpmu->hw_events);
+ u64 branch_type = event->attr.branch_sample_type;
+ u64 ctr;
+
+ if (!cpuc->ctr_users++ && !event->total_time_running)
+ riscv_pmu_ctr_clear();
+
+ ctr = branch_type_to_ctr(branch_type);
+ csr_write(CSR_CTRCTL, ctr);
+
+ perf_sched_cb_inc(event->pmu);
+}
+
+void riscv_pmu_ctr_disable(struct perf_event *event)
+{
+ struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);
+ struct cpu_hw_events *cpuc = this_cpu_ptr(rvpmu->hw_events);
+
+ /* Clear CTRCTL to disable the recording. */
+ csr_write(CSR_CTRCTL, 0);
+
+ cpuc->ctr_users--;
+ WARN_ON_ONCE(cpuc->ctr_users < 0);
+
+ perf_sched_cb_dec(event->pmu);
+}
+
+/*
+ * Check for hardware supported perf filters here. To avoid missing
+ * any new added filter in perf, we do a BUILD_BUG_ON check, so make sure
+ * to update CTR_ALLOWED_BRANCH_FILTERS or CTR_EXCLUDE_BRANCH_FILTERS
+ * defines when adding support for it in below function.
+ */
+static void __init check_available_filters(void)
+{
+ u64 ctr_ctl;
+
+ /*
+ * Ensure both perf branch filter allowed and exclude
+ * masks are always in sync with the generic perf ABI.
+ */
+ BUILD_BUG_ON(CTR_PERF_BRANCH_FILTERS != (PERF_SAMPLE_BRANCH_MAX - 1));
+
+ allowed_filters = PERF_SAMPLE_BRANCH_USER |
+ PERF_SAMPLE_BRANCH_KERNEL |
+ PERF_SAMPLE_BRANCH_ANY |
+ PERF_SAMPLE_BRANCH_HW_INDEX |
+ PERF_SAMPLE_BRANCH_NO_FLAGS |
+ PERF_SAMPLE_BRANCH_NO_CYCLES |
+ PERF_SAMPLE_BRANCH_TYPE_SAVE;
+
+ csr_write(CSR_CTRCTL, ~0);
+ ctr_ctl = csr_read(CSR_CTRCTL);
+
+ if (riscv_isa_extension_available(NULL, h))
+ allowed_filters |= PERF_SAMPLE_BRANCH_HV;
+
+ if (ctr_ctl & (CTRCTL_INDCALL_INH | CTRCTL_DIRCALL_INH))
+ allowed_filters |= PERF_SAMPLE_BRANCH_ANY_CALL;
+
+ if (ctr_ctl & (CTRCTL_RET_INH | CTRCTL_TRETINH))
+ allowed_filters |= PERF_SAMPLE_BRANCH_ANY_RETURN;
+
+ if (ctr_ctl & CTRCTL_INDCALL_INH)
+ allowed_filters |= PERF_SAMPLE_BRANCH_IND_CALL;
+
+ if (ctr_ctl & CTRCTL_TKBRINH)
+ allowed_filters |= PERF_SAMPLE_BRANCH_COND;
+
+ if (ctr_ctl & CTRCTL_RASEMU)
+ allowed_filters |= PERF_SAMPLE_BRANCH_CALL_STACK;
+
+ if (ctr_ctl & (CTRCTL_INDOJUMP_INH | CTRCTL_INDJUMP_INH))
+ allowed_filters |= PERF_SAMPLE_BRANCH_IND_JUMP;
+
+ if (ctr_ctl & CTRCTL_DIRCALL_INH)
+ allowed_filters |= PERF_SAMPLE_BRANCH_CALL;
+}
+
+void riscv_pmu_ctr_starting_cpu(void)
+{
+ if (!riscv_isa_extension_available(NULL, SxCTR) ||
+ !riscv_isa_extension_available(NULL, SSCOFPMF) ||
+ !riscv_isa_extension_available(NULL, SxCSRIND))
+ return;
+
+ /* Set depth to maximum. */
+ csr_write(CSR_SCTRDEPTH, SCTRDEPTH_MASK);
+}
+
+void riscv_pmu_ctr_dying_cpu(void)
+{
+ if (!riscv_isa_extension_available(NULL, SxCTR) ||
+ !riscv_isa_extension_available(NULL, SSCOFPMF) ||
+ !riscv_isa_extension_available(NULL, SxCSRIND))
+ return;
+
+ /* Clear and reset CTR CSRs. */
+ csr_write(CSR_SCTRDEPTH, 0);
+ csr_write(CSR_CTRCTL, 0);
+ riscv_pmu_ctr_clear();
+}
+
+void __init riscv_pmu_ctr_init(struct riscv_pmu *riscv_pmu)
+{
+ if (!riscv_isa_extension_available(NULL, SxCTR) ||
+ !riscv_isa_extension_available(NULL, SSCOFPMF) ||
+ !riscv_isa_extension_available(NULL, SxCSRIND))
+ return;
+
+ check_available_filters();
+
+ /* Set depth to maximum. */
+ csr_write(CSR_SCTRDEPTH, SCTRDEPTH_MASK);
+ riscv_pmu->ctr_depth = ctr_get_depth(csr_read(CSR_SCTRDEPTH));
+
+ pr_info("Perf CTR available, with %d depth\n", riscv_pmu->ctr_depth);
+}
+
+void __init riscv_pmu_ctr_finish(struct riscv_pmu *riscv_pmu)
+{
+ if (!riscv_pmu_ctr_supported(riscv_pmu))
+ return;
+
+ csr_write(CSR_SCTRDEPTH, 0);
+ csr_write(CSR_CTRCTL, 0);
+ riscv_pmu_ctr_clear();
+ riscv_pmu->ctr_depth = 0;
+}
@@ -104,6 +104,39 @@ struct riscv_pmu *riscv_pmu_alloc(void);
int riscv_pmu_get_hpm_info(u32 *hw_ctr_width, u32 *num_hw_ctr);
#endif
+static inline bool riscv_pmu_ctr_supported(struct riscv_pmu *pmu)
+{
+ return !!pmu->ctr_depth;
+}
+
#endif /* CONFIG_RISCV_PMU_COMMON */
+#ifdef CONFIG_RISCV_CTR
+
+bool riscv_pmu_ctr_valid(struct perf_event *event);
+void riscv_pmu_ctr_consume(struct cpu_hw_events *cpuc, struct perf_event *event);
+void riscv_pmu_ctr_sched_task(struct perf_event_pmu_context *pmu_ctx, bool sched_in);
+void riscv_pmu_ctr_enable(struct perf_event *event);
+void riscv_pmu_ctr_disable(struct perf_event *event);
+void riscv_pmu_ctr_dying_cpu(void);
+void riscv_pmu_ctr_starting_cpu(void);
+void riscv_pmu_ctr_init(struct riscv_pmu *riscv_pmu);
+void riscv_pmu_ctr_finish(struct riscv_pmu *riscv_pmu);
+
+#else
+
+static inline bool riscv_pmu_ctr_valid(struct perf_event *event) { return false; }
+static inline void riscv_pmu_ctr_consume(struct cpu_hw_events *cpuc,
+ struct perf_event *event) { }
+static inline void riscv_pmu_ctr_sched_task(struct perf_event_pmu_context *,
+ bool sched_in) { }
+static inline void riscv_pmu_ctr_enable(struct perf_event *event) { }
+static inline void riscv_pmu_ctr_disable(struct perf_event *event) { }
+static inline void riscv_pmu_ctr_dying_cpu(void) { }
+static inline void riscv_pmu_ctr_starting_cpu(void) { }
+static inline void riscv_pmu_ctr_init(struct riscv_pmu *riscv_pmu) { }
+static inline void riscv_pmu_ctr_finish(struct riscv_pmu *riscv_pmu) { }
+
+#endif /* CONFIG_RISCV_CTR */
+
#endif /* _RISCV_PMU_H */
This adds support for CTR Ext defined in [0]. The extension allows to records a maximum for 256 last branch records. CTR extension depends on s[m|s]csrind and Sscofpmf extensions. Signed-off-by: Rajnesh Kanwal <rkanwal@rivosinc.com> --- MAINTAINERS | 1 + drivers/perf/Kconfig | 11 + drivers/perf/Makefile | 1 + drivers/perf/riscv_ctr.c | 469 +++++++++++++++++++++++++++++++++ include/linux/perf/riscv_pmu.h | 33 +++ 5 files changed, 515 insertions(+) create mode 100644 drivers/perf/riscv_ctr.c