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-rw-r--r--arch/x86/kernel/cpu/perf_event_intel_lbr.c21
-rw-r--r--include/linux/perf_event.h71
-rw-r--r--kernel/events/core.c68
3 files changed, 148 insertions, 12 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
index 47a7e63..309d0cc 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
@@ -142,9 +142,11 @@ static void intel_pmu_lbr_read_32(struct cpu_hw_events *cpuc)
rdmsrl(x86_pmu.lbr_from + lbr_idx, msr_lastbranch.lbr);
- cpuc->lbr_entries[i].from = msr_lastbranch.from;
- cpuc->lbr_entries[i].to = msr_lastbranch.to;
- cpuc->lbr_entries[i].flags = 0;
+ cpuc->lbr_entries[i].from = msr_lastbranch.from;
+ cpuc->lbr_entries[i].to = msr_lastbranch.to;
+ cpuc->lbr_entries[i].mispred = 0;
+ cpuc->lbr_entries[i].predicted = 0;
+ cpuc->lbr_entries[i].reserved = 0;
}
cpuc->lbr_stack.nr = i;
}
@@ -165,19 +167,22 @@ static void intel_pmu_lbr_read_64(struct cpu_hw_events *cpuc)
for (i = 0; i < x86_pmu.lbr_nr; i++) {
unsigned long lbr_idx = (tos - i) & mask;
- u64 from, to, flags = 0;
+ u64 from, to, mis = 0, pred = 0;
rdmsrl(x86_pmu.lbr_from + lbr_idx, from);
rdmsrl(x86_pmu.lbr_to + lbr_idx, to);
if (lbr_format == LBR_FORMAT_EIP_FLAGS) {
- flags = !!(from & LBR_FROM_FLAG_MISPRED);
+ mis = !!(from & LBR_FROM_FLAG_MISPRED);
+ pred = !mis;
from = (u64)((((s64)from) << 1) >> 1);
}
- cpuc->lbr_entries[i].from = from;
- cpuc->lbr_entries[i].to = to;
- cpuc->lbr_entries[i].flags = flags;
+ cpuc->lbr_entries[i].from = from;
+ cpuc->lbr_entries[i].to = to;
+ cpuc->lbr_entries[i].mispred = mis;
+ cpuc->lbr_entries[i].predicted = pred;
+ cpuc->lbr_entries[i].reserved = 0;
}
cpuc->lbr_stack.nr = i;
}
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 64426b7..5fc494f 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -129,11 +129,40 @@ enum perf_event_sample_format {
PERF_SAMPLE_PERIOD = 1U << 8,
PERF_SAMPLE_STREAM_ID = 1U << 9,
PERF_SAMPLE_RAW = 1U << 10,
+ PERF_SAMPLE_BRANCH_STACK = 1U << 11,
- PERF_SAMPLE_MAX = 1U << 11, /* non-ABI */
+ PERF_SAMPLE_MAX = 1U << 12, /* non-ABI */
};
/*
+ * values to program into branch_sample_type when PERF_SAMPLE_BRANCH is set
+ *
+ * If the user does not pass priv level information via branch_sample_type,
+ * the kernel uses the event's priv level. Branch and event priv levels do
+ * not have to match. Branch priv level is checked for permissions.
+ *
+ * The branch types can be combined, however BRANCH_ANY covers all types
+ * of branches and therefore it supersedes all the other types.
+ */
+enum perf_branch_sample_type {
+ PERF_SAMPLE_BRANCH_USER = 1U << 0, /* user branches */
+ PERF_SAMPLE_BRANCH_KERNEL = 1U << 1, /* kernel branches */
+ PERF_SAMPLE_BRANCH_HV = 1U << 2, /* hypervisor branches */
+
+ PERF_SAMPLE_BRANCH_ANY = 1U << 3, /* any branch types */
+ PERF_SAMPLE_BRANCH_ANY_CALL = 1U << 4, /* any call branch */
+ PERF_SAMPLE_BRANCH_ANY_RETURN = 1U << 5, /* any return branch */
+ PERF_SAMPLE_BRANCH_IND_CALL = 1U << 6, /* indirect calls */
+
+ PERF_SAMPLE_BRANCH_MAX = 1U << 7, /* non-ABI */
+};
+
+#define PERF_SAMPLE_BRANCH_PLM_ALL \
+ (PERF_SAMPLE_BRANCH_USER|\
+ PERF_SAMPLE_BRANCH_KERNEL|\
+ PERF_SAMPLE_BRANCH_HV)
+
+/*
* The format of the data returned by read() on a perf event fd,
* as specified by attr.read_format:
*
@@ -240,6 +269,7 @@ struct perf_event_attr {
__u64 bp_len;
__u64 config2; /* extension of config1 */
};
+ __u64 branch_sample_type; /* enum branch_sample_type */
};
/*
@@ -458,6 +488,8 @@ enum perf_event_type {
*
* { u32 size;
* char data[size];}&& PERF_SAMPLE_RAW
+ *
+ * { u64 from, to, flags } lbr[nr];} && PERF_SAMPLE_BRANCH_STACK
* };
*/
PERF_RECORD_SAMPLE = 9,
@@ -530,12 +562,34 @@ struct perf_raw_record {
void *data;
};
+/*
+ * single taken branch record layout:
+ *
+ * from: source instruction (may not always be a branch insn)
+ * to: branch target
+ * mispred: branch target was mispredicted
+ * predicted: branch target was predicted
+ *
+ * support for mispred, predicted is optional. In case it
+ * is not supported mispred = predicted = 0.
+ */
struct perf_branch_entry {
- __u64 from;
- __u64 to;
- __u64 flags;
+ __u64 from;
+ __u64 to;
+ __u64 mispred:1, /* target mispredicted */
+ predicted:1,/* target predicted */
+ reserved:62;
};
+/*
+ * branch stack layout:
+ * nr: number of taken branches stored in entries[]
+ *
+ * Note that nr can vary from sample to sample
+ * branches (to, from) are stored from most recent
+ * to least recent, i.e., entries[0] contains the most
+ * recent branch.
+ */
struct perf_branch_stack {
__u64 nr;
struct perf_branch_entry entries[0];
@@ -566,7 +620,9 @@ struct hw_perf_event {
unsigned long event_base;
int idx;
int last_cpu;
+
struct hw_perf_event_extra extra_reg;
+ struct hw_perf_event_extra branch_reg;
};
struct { /* software */
struct hrtimer hrtimer;
@@ -1007,12 +1063,14 @@ struct perf_sample_data {
u64 period;
struct perf_callchain_entry *callchain;
struct perf_raw_record *raw;
+ struct perf_branch_stack *br_stack;
};
static inline void perf_sample_data_init(struct perf_sample_data *data, u64 addr)
{
data->addr = addr;
data->raw = NULL;
+ data->br_stack = NULL;
}
extern void perf_output_sample(struct perf_output_handle *handle,
@@ -1151,6 +1209,11 @@ extern void perf_bp_event(struct perf_event *event, void *data);
# define perf_instruction_pointer(regs) instruction_pointer(regs)
#endif
+static inline bool has_branch_stack(struct perf_event *event)
+{
+ return event->attr.sample_type & PERF_SAMPLE_BRANCH_STACK;
+}
+
extern int perf_output_begin(struct perf_output_handle *handle,
struct perf_event *event, unsigned int size);
extern void perf_output_end(struct perf_output_handle *handle);
diff --git a/kernel/events/core.c b/kernel/events/core.c
index e8b32ac..5820efd 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -118,6 +118,13 @@ static int cpu_function_call(int cpu, int (*func) (void *info), void *info)
PERF_FLAG_FD_OUTPUT |\
PERF_FLAG_PID_CGROUP)
+/*
+ * branch priv levels that need permission checks
+ */
+#define PERF_SAMPLE_BRANCH_PERM_PLM \
+ (PERF_SAMPLE_BRANCH_KERNEL |\
+ PERF_SAMPLE_BRANCH_HV)
+
enum event_type_t {
EVENT_FLEXIBLE = 0x1,
EVENT_PINNED = 0x2,
@@ -3907,6 +3914,24 @@ void perf_output_sample(struct perf_output_handle *handle,
}
}
}
+
+ if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
+ if (data->br_stack) {
+ size_t size;
+
+ size = data->br_stack->nr
+ * sizeof(struct perf_branch_entry);
+
+ perf_output_put(handle, data->br_stack->nr);
+ perf_output_copy(handle, data->br_stack->entries, size);
+ } else {
+ /*
+ * we always store at least the value of nr
+ */
+ u64 nr = 0;
+ perf_output_put(handle, nr);
+ }
+ }
}
void perf_prepare_sample(struct perf_event_header *header,
@@ -3949,6 +3974,15 @@ void perf_prepare_sample(struct perf_event_header *header,
WARN_ON_ONCE(size & (sizeof(u64)-1));
header->size += size;
}
+
+ if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
+ int size = sizeof(u64); /* nr */
+ if (data->br_stack) {
+ size += data->br_stack->nr
+ * sizeof(struct perf_branch_entry);
+ }
+ header->size += size;
+ }
}
static void perf_event_output(struct perf_event *event,
@@ -5935,6 +5969,40 @@ static int perf_copy_attr(struct perf_event_attr __user *uattr,
if (attr->read_format & ~(PERF_FORMAT_MAX-1))
return -EINVAL;
+ if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
+ u64 mask = attr->branch_sample_type;
+
+ /* only using defined bits */
+ if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
+ return -EINVAL;
+
+ /* at least one branch bit must be set */
+ if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
+ return -EINVAL;
+
+ /* kernel level capture: check permissions */
+ if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
+ && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
+ return -EACCES;
+
+ /* propagate priv level, when not set for branch */
+ if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
+
+ /* exclude_kernel checked on syscall entry */
+ if (!attr->exclude_kernel)
+ mask |= PERF_SAMPLE_BRANCH_KERNEL;
+
+ if (!attr->exclude_user)
+ mask |= PERF_SAMPLE_BRANCH_USER;
+
+ if (!attr->exclude_hv)
+ mask |= PERF_SAMPLE_BRANCH_HV;
+ /*
+ * adjust user setting (for HW filter setup)
+ */
+ attr->branch_sample_type = mask;
+ }
+ }
out:
return ret;
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