v4.19.13 snapshot.
diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
new file mode 100644
index 0000000..4ad9674
--- /dev/null
+++ b/kernel/trace/trace_branch.c
@@ -0,0 +1,451 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * unlikely profiler
+ *
+ * Copyright (C) 2008 Steven Rostedt <srostedt@redhat.com>
+ */
+#include <linux/kallsyms.h>
+#include <linux/seq_file.h>
+#include <linux/spinlock.h>
+#include <linux/irqflags.h>
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/ftrace.h>
+#include <linux/hash.h>
+#include <linux/fs.h>
+#include <asm/local.h>
+
+#include "trace.h"
+#include "trace_stat.h"
+#include "trace_output.h"
+
+#ifdef CONFIG_BRANCH_TRACER
+
+static struct tracer branch_trace;
+static int branch_tracing_enabled __read_mostly;
+static DEFINE_MUTEX(branch_tracing_mutex);
+
+static struct trace_array *branch_tracer;
+
+static void
+probe_likely_condition(struct ftrace_likely_data *f, int val, int expect)
+{
+ struct trace_event_call *call = &event_branch;
+ struct trace_array *tr = branch_tracer;
+ struct trace_array_cpu *data;
+ struct ring_buffer_event *event;
+ struct trace_branch *entry;
+ struct ring_buffer *buffer;
+ unsigned long flags;
+ int pc;
+ const char *p;
+
+ if (current->trace_recursion & TRACE_BRANCH_BIT)
+ return;
+
+ /*
+ * I would love to save just the ftrace_likely_data pointer, but
+ * this code can also be used by modules. Ugly things can happen
+ * if the module is unloaded, and then we go and read the
+ * pointer. This is slower, but much safer.
+ */
+
+ if (unlikely(!tr))
+ return;
+
+ raw_local_irq_save(flags);
+ current->trace_recursion |= TRACE_BRANCH_BIT;
+ data = this_cpu_ptr(tr->trace_buffer.data);
+ if (atomic_read(&data->disabled))
+ goto out;
+
+ pc = preempt_count();
+ buffer = tr->trace_buffer.buffer;
+ event = trace_buffer_lock_reserve(buffer, TRACE_BRANCH,
+ sizeof(*entry), flags, pc);
+ if (!event)
+ goto out;
+
+ entry = ring_buffer_event_data(event);
+
+ /* Strip off the path, only save the file */
+ p = f->data.file + strlen(f->data.file);
+ while (p >= f->data.file && *p != '/')
+ p--;
+ p++;
+
+ strncpy(entry->func, f->data.func, TRACE_FUNC_SIZE);
+ strncpy(entry->file, p, TRACE_FILE_SIZE);
+ entry->func[TRACE_FUNC_SIZE] = 0;
+ entry->file[TRACE_FILE_SIZE] = 0;
+ entry->constant = f->constant;
+ entry->line = f->data.line;
+ entry->correct = val == expect;
+
+ if (!call_filter_check_discard(call, entry, buffer, event))
+ trace_buffer_unlock_commit_nostack(buffer, event);
+
+ out:
+ current->trace_recursion &= ~TRACE_BRANCH_BIT;
+ raw_local_irq_restore(flags);
+}
+
+static inline
+void trace_likely_condition(struct ftrace_likely_data *f, int val, int expect)
+{
+ if (!branch_tracing_enabled)
+ return;
+
+ probe_likely_condition(f, val, expect);
+}
+
+int enable_branch_tracing(struct trace_array *tr)
+{
+ mutex_lock(&branch_tracing_mutex);
+ branch_tracer = tr;
+ /*
+ * Must be seen before enabling. The reader is a condition
+ * where we do not need a matching rmb()
+ */
+ smp_wmb();
+ branch_tracing_enabled++;
+ mutex_unlock(&branch_tracing_mutex);
+
+ return 0;
+}
+
+void disable_branch_tracing(void)
+{
+ mutex_lock(&branch_tracing_mutex);
+
+ if (!branch_tracing_enabled)
+ goto out_unlock;
+
+ branch_tracing_enabled--;
+
+ out_unlock:
+ mutex_unlock(&branch_tracing_mutex);
+}
+
+static int branch_trace_init(struct trace_array *tr)
+{
+ return enable_branch_tracing(tr);
+}
+
+static void branch_trace_reset(struct trace_array *tr)
+{
+ disable_branch_tracing();
+}
+
+static enum print_line_t trace_branch_print(struct trace_iterator *iter,
+ int flags, struct trace_event *event)
+{
+ struct trace_branch *field;
+
+ trace_assign_type(field, iter->ent);
+
+ trace_seq_printf(&iter->seq, "[%s] %s:%s:%d\n",
+ field->correct ? " ok " : " MISS ",
+ field->func,
+ field->file,
+ field->line);
+
+ return trace_handle_return(&iter->seq);
+}
+
+static void branch_print_header(struct seq_file *s)
+{
+ seq_puts(s, "# TASK-PID CPU# TIMESTAMP CORRECT"
+ " FUNC:FILE:LINE\n"
+ "# | | | | | "
+ " |\n");
+}
+
+static struct trace_event_functions trace_branch_funcs = {
+ .trace = trace_branch_print,
+};
+
+static struct trace_event trace_branch_event = {
+ .type = TRACE_BRANCH,
+ .funcs = &trace_branch_funcs,
+};
+
+static struct tracer branch_trace __read_mostly =
+{
+ .name = "branch",
+ .init = branch_trace_init,
+ .reset = branch_trace_reset,
+#ifdef CONFIG_FTRACE_SELFTEST
+ .selftest = trace_selftest_startup_branch,
+#endif /* CONFIG_FTRACE_SELFTEST */
+ .print_header = branch_print_header,
+};
+
+__init static int init_branch_tracer(void)
+{
+ int ret;
+
+ ret = register_trace_event(&trace_branch_event);
+ if (!ret) {
+ printk(KERN_WARNING "Warning: could not register "
+ "branch events\n");
+ return 1;
+ }
+ return register_tracer(&branch_trace);
+}
+core_initcall(init_branch_tracer);
+
+#else
+static inline
+void trace_likely_condition(struct ftrace_likely_data *f, int val, int expect)
+{
+}
+#endif /* CONFIG_BRANCH_TRACER */
+
+void ftrace_likely_update(struct ftrace_likely_data *f, int val,
+ int expect, int is_constant)
+{
+ /* A constant is always correct */
+ if (is_constant) {
+ f->constant++;
+ val = expect;
+ }
+ /*
+ * I would love to have a trace point here instead, but the
+ * trace point code is so inundated with unlikely and likely
+ * conditions that the recursive nightmare that exists is too
+ * much to try to get working. At least for now.
+ */
+ trace_likely_condition(f, val, expect);
+
+ /* FIXME: Make this atomic! */
+ if (val == expect)
+ f->data.correct++;
+ else
+ f->data.incorrect++;
+}
+EXPORT_SYMBOL(ftrace_likely_update);
+
+extern unsigned long __start_annotated_branch_profile[];
+extern unsigned long __stop_annotated_branch_profile[];
+
+static int annotated_branch_stat_headers(struct seq_file *m)
+{
+ seq_puts(m, " correct incorrect % "
+ " Function "
+ " File Line\n"
+ " ------- --------- - "
+ " -------- "
+ " ---- ----\n");
+ return 0;
+}
+
+static inline long get_incorrect_percent(struct ftrace_branch_data *p)
+{
+ long percent;
+
+ if (p->correct) {
+ percent = p->incorrect * 100;
+ percent /= p->correct + p->incorrect;
+ } else
+ percent = p->incorrect ? 100 : -1;
+
+ return percent;
+}
+
+static const char *branch_stat_process_file(struct ftrace_branch_data *p)
+{
+ const char *f;
+
+ /* Only print the file, not the path */
+ f = p->file + strlen(p->file);
+ while (f >= p->file && *f != '/')
+ f--;
+ return ++f;
+}
+
+static void branch_stat_show(struct seq_file *m,
+ struct ftrace_branch_data *p, const char *f)
+{
+ long percent;
+
+ /*
+ * The miss is overlayed on correct, and hit on incorrect.
+ */
+ percent = get_incorrect_percent(p);
+
+ if (percent < 0)
+ seq_puts(m, " X ");
+ else
+ seq_printf(m, "%3ld ", percent);
+
+ seq_printf(m, "%-30.30s %-20.20s %d\n", p->func, f, p->line);
+}
+
+static int branch_stat_show_normal(struct seq_file *m,
+ struct ftrace_branch_data *p, const char *f)
+{
+ seq_printf(m, "%8lu %8lu ", p->correct, p->incorrect);
+ branch_stat_show(m, p, f);
+ return 0;
+}
+
+static int annotate_branch_stat_show(struct seq_file *m, void *v)
+{
+ struct ftrace_likely_data *p = v;
+ const char *f;
+ int l;
+
+ f = branch_stat_process_file(&p->data);
+
+ if (!p->constant)
+ return branch_stat_show_normal(m, &p->data, f);
+
+ l = snprintf(NULL, 0, "/%lu", p->constant);
+ l = l > 8 ? 0 : 8 - l;
+
+ seq_printf(m, "%8lu/%lu %*lu ",
+ p->data.correct, p->constant, l, p->data.incorrect);
+ branch_stat_show(m, &p->data, f);
+ return 0;
+}
+
+static void *annotated_branch_stat_start(struct tracer_stat *trace)
+{
+ return __start_annotated_branch_profile;
+}
+
+static void *
+annotated_branch_stat_next(void *v, int idx)
+{
+ struct ftrace_likely_data *p = v;
+
+ ++p;
+
+ if ((void *)p >= (void *)__stop_annotated_branch_profile)
+ return NULL;
+
+ return p;
+}
+
+static int annotated_branch_stat_cmp(void *p1, void *p2)
+{
+ struct ftrace_branch_data *a = p1;
+ struct ftrace_branch_data *b = p2;
+
+ long percent_a, percent_b;
+
+ percent_a = get_incorrect_percent(a);
+ percent_b = get_incorrect_percent(b);
+
+ if (percent_a < percent_b)
+ return -1;
+ if (percent_a > percent_b)
+ return 1;
+
+ if (a->incorrect < b->incorrect)
+ return -1;
+ if (a->incorrect > b->incorrect)
+ return 1;
+
+ /*
+ * Since the above shows worse (incorrect) cases
+ * first, we continue that by showing best (correct)
+ * cases last.
+ */
+ if (a->correct > b->correct)
+ return -1;
+ if (a->correct < b->correct)
+ return 1;
+
+ return 0;
+}
+
+static struct tracer_stat annotated_branch_stats = {
+ .name = "branch_annotated",
+ .stat_start = annotated_branch_stat_start,
+ .stat_next = annotated_branch_stat_next,
+ .stat_cmp = annotated_branch_stat_cmp,
+ .stat_headers = annotated_branch_stat_headers,
+ .stat_show = annotate_branch_stat_show
+};
+
+__init static int init_annotated_branch_stats(void)
+{
+ int ret;
+
+ ret = register_stat_tracer(&annotated_branch_stats);
+ if (!ret) {
+ printk(KERN_WARNING "Warning: could not register "
+ "annotated branches stats\n");
+ return 1;
+ }
+ return 0;
+}
+fs_initcall(init_annotated_branch_stats);
+
+#ifdef CONFIG_PROFILE_ALL_BRANCHES
+
+extern unsigned long __start_branch_profile[];
+extern unsigned long __stop_branch_profile[];
+
+static int all_branch_stat_headers(struct seq_file *m)
+{
+ seq_puts(m, " miss hit % "
+ " Function "
+ " File Line\n"
+ " ------- --------- - "
+ " -------- "
+ " ---- ----\n");
+ return 0;
+}
+
+static void *all_branch_stat_start(struct tracer_stat *trace)
+{
+ return __start_branch_profile;
+}
+
+static void *
+all_branch_stat_next(void *v, int idx)
+{
+ struct ftrace_branch_data *p = v;
+
+ ++p;
+
+ if ((void *)p >= (void *)__stop_branch_profile)
+ return NULL;
+
+ return p;
+}
+
+static int all_branch_stat_show(struct seq_file *m, void *v)
+{
+ struct ftrace_branch_data *p = v;
+ const char *f;
+
+ f = branch_stat_process_file(p);
+ return branch_stat_show_normal(m, p, f);
+}
+
+static struct tracer_stat all_branch_stats = {
+ .name = "branch_all",
+ .stat_start = all_branch_stat_start,
+ .stat_next = all_branch_stat_next,
+ .stat_headers = all_branch_stat_headers,
+ .stat_show = all_branch_stat_show
+};
+
+__init static int all_annotated_branch_stats(void)
+{
+ int ret;
+
+ ret = register_stat_tracer(&all_branch_stats);
+ if (!ret) {
+ printk(KERN_WARNING "Warning: could not register "
+ "all branches stats\n");
+ return 1;
+ }
+ return 0;
+}
+fs_initcall(all_annotated_branch_stats);
+#endif /* CONFIG_PROFILE_ALL_BRANCHES */