1 files changed, 439 insertions, 0 deletions
diff --git a/arch/x86/events/amd/lbr.c b/arch/x86/events/amd/lbr.c
new file mode 100644
index 000000000..38a75216c
--- /dev/null
+++ b/arch/x86/events/amd/lbr.c
@@ -0,0 +1,439 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/perf_event.h>
+#include <asm/perf_event.h>
+
+#include "../perf_event.h"
+
+/* LBR Branch Select valid bits */
+#define LBR_SELECT_MASK		0x1ff
+
+/*
+ * LBR Branch Select filter bits which when set, ensures that the
+ * corresponding type of branches are not recorded
+ */
+#define LBR_SELECT_KERNEL		0	/* Branches ending in CPL = 0 */
+#define LBR_SELECT_USER			1	/* Branches ending in CPL > 0 */
+#define LBR_SELECT_JCC			2	/* Conditional branches */
+#define LBR_SELECT_CALL_NEAR_REL	3	/* Near relative calls */
+#define LBR_SELECT_CALL_NEAR_IND	4	/* Indirect relative calls */
+#define LBR_SELECT_RET_NEAR		5	/* Near returns */
+#define LBR_SELECT_JMP_NEAR_IND		6	/* Near indirect jumps (excl. calls and returns) */
+#define LBR_SELECT_JMP_NEAR_REL		7	/* Near relative jumps (excl. calls) */
+#define LBR_SELECT_FAR_BRANCH		8	/* Far branches */
+
+#define LBR_KERNEL	BIT(LBR_SELECT_KERNEL)
+#define LBR_USER	BIT(LBR_SELECT_USER)
+#define LBR_JCC		BIT(LBR_SELECT_JCC)
+#define LBR_REL_CALL	BIT(LBR_SELECT_CALL_NEAR_REL)
+#define LBR_IND_CALL	BIT(LBR_SELECT_CALL_NEAR_IND)
+#define LBR_RETURN	BIT(LBR_SELECT_RET_NEAR)
+#define LBR_REL_JMP	BIT(LBR_SELECT_JMP_NEAR_REL)
+#define LBR_IND_JMP	BIT(LBR_SELECT_JMP_NEAR_IND)
+#define LBR_FAR		BIT(LBR_SELECT_FAR_BRANCH)
+#define LBR_NOT_SUPP	-1	/* unsupported filter */
+#define LBR_IGNORE	0
+
+#define LBR_ANY		\
+	(LBR_JCC | LBR_REL_CALL | LBR_IND_CALL | LBR_RETURN |	\
+	 LBR_REL_JMP | LBR_IND_JMP | LBR_FAR)
+
+struct branch_entry {
+	union {
+		struct {
+			u64	ip:58;
+			u64	ip_sign_ext:5;
+			u64	mispredict:1;
+		} split;
+		u64		full;
+	} from;
+
+	union {
+		struct {
+			u64	ip:58;
+			u64	ip_sign_ext:3;
+			u64	reserved:1;
+			u64	spec:1;
+			u64	valid:1;
+		} split;
+		u64		full;
+	} to;
+};
+
+static __always_inline void amd_pmu_lbr_set_from(unsigned int idx, u64 val)
+{
+	wrmsrl(MSR_AMD_SAMP_BR_FROM + idx * 2, val);
+}
+
+static __always_inline void amd_pmu_lbr_set_to(unsigned int idx, u64 val)
+{
+	wrmsrl(MSR_AMD_SAMP_BR_FROM + idx * 2 + 1, val);
+}
+
+static __always_inline u64 amd_pmu_lbr_get_from(unsigned int idx)
+{
+	u64 val;
+
+	rdmsrl(MSR_AMD_SAMP_BR_FROM + idx * 2, val);
+
+	return val;
+}
+
+static __always_inline u64 amd_pmu_lbr_get_to(unsigned int idx)
+{
+	u64 val;
+
+	rdmsrl(MSR_AMD_SAMP_BR_FROM + idx * 2 + 1, val);
+
+	return val;
+}
+
+static __always_inline u64 sign_ext_branch_ip(u64 ip)
+{
+	u32 shift = 64 - boot_cpu_data.x86_virt_bits;
+
+	return (u64)(((s64)ip << shift) >> shift);
+}
+
+static void amd_pmu_lbr_filter(void)
+{
+	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+	int br_sel = cpuc->br_sel, offset, type, i, j;
+	bool compress = false;
+	bool fused_only = false;
+	u64 from, to;
+
+	/* If sampling all branches, there is nothing to filter */
+	if (((br_sel & X86_BR_ALL) == X86_BR_ALL) &&
+	    ((br_sel & X86_BR_TYPE_SAVE) != X86_BR_TYPE_SAVE))
+		fused_only = true;
+
+	for (i = 0; i < cpuc->lbr_stack.nr; i++) {
+		from = cpuc->lbr_entries[i].from;
+		to = cpuc->lbr_entries[i].to;
+		type = branch_type_fused(from, to, 0, &offset);
+
+		/*
+		 * Adjust the branch from address in case of instruction
+		 * fusion where it points to an instruction preceding the
+		 * actual branch
+		 */
+		if (offset) {
+			cpuc->lbr_entries[i].from += offset;
+			if (fused_only)
+				continue;
+		}
+
+		/* If type does not correspond, then discard */
+		if (type == X86_BR_NONE || (br_sel & type) != type) {
+			cpuc->lbr_entries[i].from = 0;	/* mark invalid */
+			compress = true;
+		}
+
+		if ((br_sel & X86_BR_TYPE_SAVE) == X86_BR_TYPE_SAVE)
+			cpuc->lbr_entries[i].type = common_branch_type(type);
+	}
+
+	if (!compress)
+		return;
+
+	/* Remove all invalid entries */
+	for (i = 0; i < cpuc->lbr_stack.nr; ) {
+		if (!cpuc->lbr_entries[i].from) {
+			j = i;
+			while (++j < cpuc->lbr_stack.nr)
+				cpuc->lbr_entries[j - 1] = cpuc->lbr_entries[j];
+			cpuc->lbr_stack.nr--;
+			if (!cpuc->lbr_entries[i].from)
+				continue;
+		}
+		i++;
+	}
+}
+
+static const int lbr_spec_map[PERF_BR_SPEC_MAX] = {
+	PERF_BR_SPEC_NA,
+	PERF_BR_SPEC_WRONG_PATH,
+	PERF_BR_NON_SPEC_CORRECT_PATH,
+	PERF_BR_SPEC_CORRECT_PATH,
+};
+
+void amd_pmu_lbr_read(void)
+{
+	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+	struct perf_branch_entry *br = cpuc->lbr_entries;
+	struct branch_entry entry;
+	int out = 0, idx, i;
+
+	if (!cpuc->lbr_users)
+		return;
+
+	for (i = 0; i < x86_pmu.lbr_nr; i++) {
+		entry.from.full	= amd_pmu_lbr_get_from(i);
+		entry.to.full	= amd_pmu_lbr_get_to(i);
+
+		/*
+		 * Check if a branch has been logged; if valid = 0, spec = 0
+		 * then no branch was recorded
+		 */
+		if (!entry.to.split.valid && !entry.to.split.spec)
+			continue;
+
+		perf_clear_branch_entry_bitfields(br + out);
+
+		br[out].from	= sign_ext_branch_ip(entry.from.split.ip);
+		br[out].to	= sign_ext_branch_ip(entry.to.split.ip);
+		br[out].mispred	= entry.from.split.mispredict;
+		br[out].predicted = !br[out].mispred;
+
+		/*
+		 * Set branch speculation information using the status of
+		 * the valid and spec bits.
+		 *
+		 * When valid = 0, spec = 0, no branch was recorded and the
+		 * entry is discarded as seen above.
+		 *
+		 * When valid = 0, spec = 1, the recorded branch was
+		 * speculative but took the wrong path.
+		 *
+		 * When valid = 1, spec = 0, the recorded branch was
+		 * non-speculative but took the correct path.
+		 *
+		 * When valid = 1, spec = 1, the recorded branch was
+		 * speculative and took the correct path
+		 */
+		idx = (entry.to.split.valid << 1) | entry.to.split.spec;
+		br[out].spec = lbr_spec_map[idx];
+		out++;
+	}
+
+	cpuc->lbr_stack.nr = out;
+
+	/*
+	 * Internal register renaming always ensures that LBR From[0] and
+	 * LBR To[0] always represent the TOS
+	 */
+	cpuc->lbr_stack.hw_idx = 0;
+
+	/* Perform further software filtering */
+	amd_pmu_lbr_filter();
+}
+
+static const int lbr_select_map[PERF_SAMPLE_BRANCH_MAX_SHIFT] = {
+	[PERF_SAMPLE_BRANCH_USER_SHIFT]		= LBR_USER,
+	[PERF_SAMPLE_BRANCH_KERNEL_SHIFT]	= LBR_KERNEL,
+	[PERF_SAMPLE_BRANCH_HV_SHIFT]		= LBR_IGNORE,
+
+	[PERF_SAMPLE_BRANCH_ANY_SHIFT]		= LBR_ANY,
+	[PERF_SAMPLE_BRANCH_ANY_CALL_SHIFT]	= LBR_REL_CALL | LBR_IND_CALL | LBR_FAR,
+	[PERF_SAMPLE_BRANCH_ANY_RETURN_SHIFT]	= LBR_RETURN | LBR_FAR,
+	[PERF_SAMPLE_BRANCH_IND_CALL_SHIFT]	= LBR_IND_CALL,
+	[PERF_SAMPLE_BRANCH_ABORT_TX_SHIFT]	= LBR_NOT_SUPP,
+	[PERF_SAMPLE_BRANCH_IN_TX_SHIFT]	= LBR_NOT_SUPP,
+	[PERF_SAMPLE_BRANCH_NO_TX_SHIFT]	= LBR_NOT_SUPP,
+	[PERF_SAMPLE_BRANCH_COND_SHIFT]		= LBR_JCC,
+
+	[PERF_SAMPLE_BRANCH_CALL_STACK_SHIFT]	= LBR_NOT_SUPP,
+	[PERF_SAMPLE_BRANCH_IND_JUMP_SHIFT]	= LBR_IND_JMP,
+	[PERF_SAMPLE_BRANCH_CALL_SHIFT]		= LBR_REL_CALL,
+
+	[PERF_SAMPLE_BRANCH_NO_FLAGS_SHIFT]	= LBR_NOT_SUPP,
+	[PERF_SAMPLE_BRANCH_NO_CYCLES_SHIFT]	= LBR_NOT_SUPP,
+};
+
+static int amd_pmu_lbr_setup_filter(struct perf_event *event)
+{
+	struct hw_perf_event_extra *reg = &event->hw.branch_reg;
+	u64 br_type = event->attr.branch_sample_type;
+	u64 mask = 0, v;
+	int i;
+
+	/* No LBR support */
+	if (!x86_pmu.lbr_nr)
+		return -EOPNOTSUPP;
+
+	if (br_type & PERF_SAMPLE_BRANCH_USER)
+		mask |= X86_BR_USER;
+
+	if (br_type & PERF_SAMPLE_BRANCH_KERNEL)
+		mask |= X86_BR_KERNEL;
+
+	/* Ignore BRANCH_HV here */
+
+	if (br_type & PERF_SAMPLE_BRANCH_ANY)
+		mask |= X86_BR_ANY;
+
+	if (br_type & PERF_SAMPLE_BRANCH_ANY_CALL)
+		mask |= X86_BR_ANY_CALL;
+
+	if (br_type & PERF_SAMPLE_BRANCH_ANY_RETURN)
+		mask |= X86_BR_RET | X86_BR_IRET | X86_BR_SYSRET;
+
+	if (br_type & PERF_SAMPLE_BRANCH_IND_CALL)
+		mask |= X86_BR_IND_CALL;
+
+	if (br_type & PERF_SAMPLE_BRANCH_COND)
+		mask |= X86_BR_JCC;
+
+	if (br_type & PERF_SAMPLE_BRANCH_IND_JUMP)
+		mask |= X86_BR_IND_JMP;
+
+	if (br_type & PERF_SAMPLE_BRANCH_CALL)
+		mask |= X86_BR_CALL | X86_BR_ZERO_CALL;
+
+	if (br_type & PERF_SAMPLE_BRANCH_TYPE_SAVE)
+		mask |= X86_BR_TYPE_SAVE;
+
+	reg->reg = mask;
+	mask = 0;
+
+	for (i = 0; i < PERF_SAMPLE_BRANCH_MAX_SHIFT; i++) {
+		if (!(br_type & BIT_ULL(i)))
+			continue;
+
+		v = lbr_select_map[i];
+		if (v == LBR_NOT_SUPP)
+			return -EOPNOTSUPP;
+
+		if (v != LBR_IGNORE)
+			mask |= v;
+	}
+
+	/* Filter bits operate in suppress mode */
+	reg->config = mask ^ LBR_SELECT_MASK;
+
+	return 0;
+}
+
+int amd_pmu_lbr_hw_config(struct perf_event *event)
+{
+	int ret = 0;
+
+	/* LBR is not recommended in counting mode */
+	if (!is_sampling_event(event))
+		return -EINVAL;
+
+	ret = amd_pmu_lbr_setup_filter(event);
+	if (!ret)
+		event->attach_state |= PERF_ATTACH_SCHED_CB;
+
+	return ret;
+}
+
+void amd_pmu_lbr_reset(void)
+{
+	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+	int i;
+
+	if (!x86_pmu.lbr_nr)
+		return;
+
+	/* Reset all branch records individually */
+	for (i = 0; i < x86_pmu.lbr_nr; i++) {
+		amd_pmu_lbr_set_from(i, 0);
+		amd_pmu_lbr_set_to(i, 0);
+	}
+
+	cpuc->last_task_ctx = NULL;
+	cpuc->last_log_id = 0;
+	wrmsrl(MSR_AMD64_LBR_SELECT, 0);
+}
+
+void amd_pmu_lbr_add(struct perf_event *event)
+{
+	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+	struct hw_perf_event_extra *reg = &event->hw.branch_reg;
+
+	if (!x86_pmu.lbr_nr)
+		return;
+
+	if (has_branch_stack(event)) {
+		cpuc->lbr_select = 1;
+		cpuc->lbr_sel->config = reg->config;
+		cpuc->br_sel = reg->reg;
+	}
+
+	perf_sched_cb_inc(event->ctx->pmu);
+
+	if (!cpuc->lbr_users++ && !event->total_time_running)
+		amd_pmu_lbr_reset();
+}
+
+void amd_pmu_lbr_del(struct perf_event *event)
+{
+	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+
+	if (!x86_pmu.lbr_nr)
+		return;
+
+	if (has_branch_stack(event))
+		cpuc->lbr_select = 0;
+
+	cpuc->lbr_users--;
+	WARN_ON_ONCE(cpuc->lbr_users < 0);
+	perf_sched_cb_dec(event->ctx->pmu);
+}
+
+void amd_pmu_lbr_sched_task(struct perf_event_context *ctx, bool sched_in)
+{
+	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+
+	/*
+	 * A context switch can flip the address space and LBR entries are
+	 * not tagged with an identifier. Hence, branches cannot be resolved
+	 * from the old address space and the LBR records should be wiped.
+	 */
+	if (cpuc->lbr_users && sched_in)
+		amd_pmu_lbr_reset();
+}
+
+void amd_pmu_lbr_enable_all(void)
+{
+	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+	u64 lbr_select, dbg_ctl, dbg_extn_cfg;
+
+	if (!cpuc->lbr_users || !x86_pmu.lbr_nr)
+		return;
+
+	/* Set hardware branch filter */
+	if (cpuc->lbr_select) {
+		lbr_select = cpuc->lbr_sel->config & LBR_SELECT_MASK;
+		wrmsrl(MSR_AMD64_LBR_SELECT, lbr_select);
+	}
+
+	rdmsrl(MSR_IA32_DEBUGCTLMSR, dbg_ctl);
+	rdmsrl(MSR_AMD_DBG_EXTN_CFG, dbg_extn_cfg);
+
+	wrmsrl(MSR_IA32_DEBUGCTLMSR, dbg_ctl | DEBUGCTLMSR_FREEZE_LBRS_ON_PMI);
+	wrmsrl(MSR_AMD_DBG_EXTN_CFG, dbg_extn_cfg | DBG_EXTN_CFG_LBRV2EN);
+}
+
+void amd_pmu_lbr_disable_all(void)
+{
+	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+	u64 dbg_ctl, dbg_extn_cfg;
+
+	if (!cpuc->lbr_users || !x86_pmu.lbr_nr)
+		return;
+
+	rdmsrl(MSR_AMD_DBG_EXTN_CFG, dbg_extn_cfg);
+	rdmsrl(MSR_IA32_DEBUGCTLMSR, dbg_ctl);
+
+	wrmsrl(MSR_AMD_DBG_EXTN_CFG, dbg_extn_cfg & ~DBG_EXTN_CFG_LBRV2EN);
+	wrmsrl(MSR_IA32_DEBUGCTLMSR, dbg_ctl & ~DEBUGCTLMSR_FREEZE_LBRS_ON_PMI);
+}
+
+__init int amd_pmu_lbr_init(void)
+{
+	union cpuid_0x80000022_ebx ebx;
+
+	if (x86_pmu.version < 2 || !boot_cpu_has(X86_FEATURE_AMD_LBR_V2))
+		return -EOPNOTSUPP;
+
+	/* Set number of entries */
+	ebx.full = cpuid_ebx(EXT_PERFMON_DEBUG_FEATURES);
+	x86_pmu.lbr_nr = ebx.split.lbr_v2_stack_sz;
+
+	pr_cont("%d-deep LBR, ", x86_pmu.lbr_nr);
+
+	return 0;
+}