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-rw-r--r--include/linux/ftrace.h10
-rw-r--r--kernel/trace/trace.c273
-rw-r--r--kernel/trace/trace.h11
-rw-r--r--kernel/trace/trace_selftest.c11
4 files changed, 272 insertions, 33 deletions
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 6b232a2460c..f53b975e32f 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -157,9 +157,18 @@ static inline void __ftrace_enabled_restore(int enabled)
#ifdef CONFIG_TRACING
extern void
ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
+# define ftrace_printk(x...) __ftrace_printk(_THIS_IP_, x)
+extern int
+__ftrace_printk(unsigned long ip, const char *fmt, ...)
+ __attribute__ ((format (printf, 2, 3)));
#else
static inline void
ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { }
+static inline int
+ftrace_printk(const char *fmt, ...) __attribute__ ((format (printf, 1, 0)))
+{
+ return 0;
+}
#endif
#ifdef CONFIG_FTRACE_MCOUNT_RECORD
@@ -173,4 +182,5 @@ ftrace_init_module(unsigned long *start, unsigned long *end) { }
static inline void ftrace_release(void *start, unsigned long size) { }
#endif
+
#endif /* _LINUX_FTRACE_H */
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 76dfe6d2466..a917bea8271 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -197,12 +197,14 @@ unsigned long nsecs_to_usecs(unsigned long nsecs)
* NEED_RESCED - reschedule is requested
* HARDIRQ - inside an interrupt handler
* SOFTIRQ - inside a softirq handler
+ * CONT - multiple entries hold the trace item
*/
enum trace_flag_type {
TRACE_FLAG_IRQS_OFF = 0x01,
TRACE_FLAG_NEED_RESCHED = 0x02,
TRACE_FLAG_HARDIRQ = 0x04,
TRACE_FLAG_SOFTIRQ = 0x08,
+ TRACE_FLAG_CONT = 0x10,
};
/*
@@ -1074,6 +1076,7 @@ enum trace_file_type {
TRACE_FILE_LAT_FMT = 1,
};
+/* Return the current entry. */
static struct trace_entry *
trace_entry_idx(struct trace_array *tr, struct trace_array_cpu *data,
struct trace_iterator *iter, int cpu)
@@ -1104,8 +1107,58 @@ trace_entry_idx(struct trace_array *tr, struct trace_array_cpu *data,
return &array[iter->next_page_idx[cpu]];
}
+/* Increment the index counter of an iterator by one */
+static void trace_iterator_increment(struct trace_iterator *iter, int cpu)
+{
+ iter->idx++;
+ iter->next_idx[cpu]++;
+ iter->next_page_idx[cpu]++;
+
+ if (iter->next_page_idx[cpu] >= ENTRIES_PER_PAGE) {
+ struct trace_array_cpu *data = iter->tr->data[cpu];
+
+ iter->next_page_idx[cpu] = 0;
+ iter->next_page[cpu] =
+ trace_next_list(data, iter->next_page[cpu]);
+ }
+}
+
static struct trace_entry *
-find_next_entry(struct trace_iterator *iter, int *ent_cpu)
+trace_entry_next(struct trace_array *tr, struct trace_array_cpu *data,
+ struct trace_iterator *iter, int cpu)
+{
+ struct list_head *next_page;
+ struct trace_entry *ent;
+ int idx, next_idx, next_page_idx;
+
+ ent = trace_entry_idx(tr, tr->data[cpu], iter, cpu);
+
+ if (likely(!ent || ent->type != TRACE_CONT))
+ return ent;
+
+ /* save the iterator details */
+ idx = iter->idx;
+ next_idx = iter->next_idx[cpu];
+ next_page_idx = iter->next_page_idx[cpu];
+ next_page = iter->next_page[cpu];
+
+ /* find a real entry */
+ do {
+ trace_iterator_increment(iter, cpu);
+ ent = trace_entry_idx(tr, tr->data[cpu], iter, cpu);
+ } while (ent && ent->type != TRACE_CONT);
+
+ /* reset the iterator */
+ iter->idx = idx;
+ iter->next_idx[cpu] = next_idx;
+ iter->next_page_idx[cpu] = next_page_idx;
+ iter->next_page[cpu] = next_page;
+
+ return ent;
+}
+
+static struct trace_entry *
+__find_next_entry(struct trace_iterator *iter, int *ent_cpu, int inc)
{
struct trace_array *tr = iter->tr;
struct trace_entry *ent, *next = NULL;
@@ -1115,7 +1168,23 @@ find_next_entry(struct trace_iterator *iter, int *ent_cpu)
for_each_tracing_cpu(cpu) {
if (!head_page(tr->data[cpu]))
continue;
+
ent = trace_entry_idx(tr, tr->data[cpu], iter, cpu);
+
+ if (ent && ent->type == TRACE_CONT) {
+ struct trace_array_cpu *data = tr->data[cpu];
+
+ if (!inc)
+ ent = trace_entry_next(tr, data, iter, cpu);
+ else {
+ while (ent && ent->type == TRACE_CONT) {
+ trace_iterator_increment(iter, cpu);
+ ent = trace_entry_idx(tr, tr->data[cpu],
+ iter, cpu);
+ }
+ }
+ }
+
/*
* Pick the entry with the smallest timestamp:
*/
@@ -1131,25 +1200,39 @@ find_next_entry(struct trace_iterator *iter, int *ent_cpu)
return next;
}
-static void trace_iterator_increment(struct trace_iterator *iter)
+/* Find the next real entry, without updating the iterator itself */
+static struct trace_entry *
+find_next_entry(struct trace_iterator *iter, int *ent_cpu)
{
- iter->idx++;
- iter->next_idx[iter->cpu]++;
- iter->next_page_idx[iter->cpu]++;
+ return __find_next_entry(iter, ent_cpu, 0);
+}
+
+/* Find the next real entry, and increment the iterator to the next entry */
+static void *find_next_entry_inc(struct trace_iterator *iter)
+{
+ struct trace_entry *next;
+ int next_cpu = -1;
- if (iter->next_page_idx[iter->cpu] >= ENTRIES_PER_PAGE) {
- struct trace_array_cpu *data = iter->tr->data[iter->cpu];
+ next = __find_next_entry(iter, &next_cpu, 1);
- iter->next_page_idx[iter->cpu] = 0;
- iter->next_page[iter->cpu] =
- trace_next_list(data, iter->next_page[iter->cpu]);
- }
+ iter->prev_ent = iter->ent;
+ iter->prev_cpu = iter->cpu;
+
+ iter->ent = next;
+ iter->cpu = next_cpu;
+
+ if (next)
+ trace_iterator_increment(iter, iter->cpu);
+
+ return next ? iter : NULL;
}
static void trace_consume(struct trace_iterator *iter)
{
struct trace_array_cpu *data = iter->tr->data[iter->cpu];
+ struct trace_entry *ent;
+ again:
data->trace_tail_idx++;
if (data->trace_tail_idx >= ENTRIES_PER_PAGE) {
data->trace_tail = trace_next_page(data, data->trace_tail);
@@ -1160,25 +1243,11 @@ static void trace_consume(struct trace_iterator *iter)
if (data->trace_head == data->trace_tail &&
data->trace_head_idx == data->trace_tail_idx)
data->trace_idx = 0;
-}
-
-static void *find_next_entry_inc(struct trace_iterator *iter)
-{
- struct trace_entry *next;
- int next_cpu = -1;
-
- next = find_next_entry(iter, &next_cpu);
-
- iter->prev_ent = iter->ent;
- iter->prev_cpu = iter->cpu;
-
- iter->ent = next;
- iter->cpu = next_cpu;
-
- if (next)
- trace_iterator_increment(iter);
- return next ? iter : NULL;
+ ent = trace_entry_idx(iter->tr, iter->tr->data[iter->cpu],
+ iter, iter->cpu);
+ if (ent && ent->type == TRACE_CONT)
+ goto again;
}
static void *s_next(struct seq_file *m, void *v, loff_t *pos)
@@ -1473,6 +1542,26 @@ lat_print_timestamp(struct trace_seq *s, unsigned long long abs_usecs,
static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
+static void
+trace_seq_print_cont(struct trace_seq *s, struct trace_iterator *iter)
+{
+ struct trace_array *tr = iter->tr;
+ struct trace_array_cpu *data = tr->data[iter->cpu];
+ struct trace_entry *ent;
+
+ ent = trace_entry_idx(tr, data, iter, iter->cpu);
+ if (!ent || ent->type != TRACE_CONT) {
+ trace_seq_putc(s, '\n');
+ return;
+ }
+
+ do {
+ trace_seq_printf(s, "%s", ent->cont.buf);
+ trace_iterator_increment(iter, iter->cpu);
+ ent = trace_entry_idx(tr, data, iter, iter->cpu);
+ } while (ent && ent->type == TRACE_CONT);
+}
+
static int
print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu)
{
@@ -1491,6 +1580,10 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu)
if (!next_entry)
next_entry = entry;
+
+ if (entry->type == TRACE_CONT)
+ return 1;
+
rel_usecs = ns2usecs(next_entry->field.t - entry->field.t);
abs_usecs = ns2usecs(entry->field.t - iter->tr->time_start);
@@ -1550,6 +1643,12 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu)
}
trace_seq_puts(s, "\n");
break;
+ case TRACE_PRINT:
+ seq_print_ip_sym(s, field->print.ip, sym_flags);
+ trace_seq_printf(s, ": %s", field->print.buf);
+ if (field->flags && TRACE_FLAG_CONT)
+ trace_seq_print_cont(s, iter);
+ break;
default:
trace_seq_printf(s, "Unknown type %d\n", entry->type);
}
@@ -1571,6 +1670,10 @@ static int print_trace_fmt(struct trace_iterator *iter)
int i;
entry = iter->ent;
+
+ if (entry->type == TRACE_CONT)
+ return 1;
+
field = &entry->field;
comm = trace_find_cmdline(iter->ent->field.pid);
@@ -1653,6 +1756,12 @@ static int print_trace_fmt(struct trace_iterator *iter)
if (!ret)
return 0;
break;
+ case TRACE_PRINT:
+ seq_print_ip_sym(s, field->print.ip, sym_flags);
+ trace_seq_printf(s, ": %s", field->print.buf);
+ if (field->flags && TRACE_FLAG_CONT)
+ trace_seq_print_cont(s, iter);
+ break;
}
return 1;
}
@@ -1666,6 +1775,10 @@ static int print_raw_fmt(struct trace_iterator *iter)
int S, T;
entry = iter->ent;
+
+ if (entry->type == TRACE_CONT)
+ return 1;
+
field = &entry->field;
ret = trace_seq_printf(s, "%d %d %llu ",
@@ -1708,6 +1821,12 @@ static int print_raw_fmt(struct trace_iterator *iter)
if (!ret)
return 0;
break;
+ case TRACE_PRINT:
+ trace_seq_printf(s, "# %lx %s",
+ field->print.ip, field->print.buf);
+ if (field->flags && TRACE_FLAG_CONT)
+ trace_seq_print_cont(s, iter);
+ break;
}
return 1;
}
@@ -1733,6 +1852,10 @@ static int print_hex_fmt(struct trace_iterator *iter)
int S, T;
entry = iter->ent;
+
+ if (entry->type == TRACE_CONT)
+ return 1;
+
field = &entry->field;
SEQ_PUT_HEX_FIELD_RET(s, field->pid);
@@ -1778,6 +1901,10 @@ static int print_bin_fmt(struct trace_iterator *iter)
struct trace_field *field;
entry = iter->ent;
+
+ if (entry->type == TRACE_CONT)
+ return 1;
+
field = &entry->field;
SEQ_PUT_FIELD_RET(s, field->pid);
@@ -2943,6 +3070,94 @@ static __init void tracer_init_debugfs(void)
#endif
}
+#define TRACE_BUF_SIZE 1024
+#define TRACE_PRINT_BUF_SIZE \
+ (sizeof(struct trace_field) - offsetof(struct trace_field, print.buf))
+#define TRACE_CONT_BUF_SIZE sizeof(struct trace_field)
+
+/**
+ * ftrace_printk - printf formatting in the ftrace buffer
+ * @fmt - the printf format for printing.
+ *
+ * Note: __ftrace_printk is an internal function for ftrace_printk and
+ * the @ip is passed in via the ftrace_printk macro.
+ *
+ * This function allows a kernel developer to debug fast path sections
+ * that printk is not appropriate for. By scattering in various
+ * printk like tracing in the code, a developer can quickly see
+ * where problems are occurring.
+ *
+ * This is intended as a debugging tool for the developer only.
+ * Please reframe from leaving ftrace_printks scattered around in
+ * your code.
+ */
+int __ftrace_printk(unsigned long ip, const char *fmt, ...)
+{
+ struct trace_array *tr = &global_trace;
+ static DEFINE_SPINLOCK(trace_buf_lock);
+ static char trace_buf[TRACE_BUF_SIZE];
+ struct trace_array_cpu *data;
+ struct trace_entry *entry;
+ unsigned long flags;
+ long disabled;
+ va_list ap;
+ int cpu, len = 0, write, written = 0;
+
+ if (likely(!ftrace_function_enabled))
+ return 0;
+
+ local_irq_save(flags);
+ cpu = raw_smp_processor_id();
+ data = tr->data[cpu];
+ disabled = atomic_inc_return(&data->disabled);
+
+ if (unlikely(disabled != 1 || !ftrace_function_enabled))
+ goto out;
+
+ spin_lock(&trace_buf_lock);
+ va_start(ap, fmt);
+ len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, ap);
+ va_end(ap);
+
+ len = min(len, TRACE_BUF_SIZE-1);
+ trace_buf[len] = 0;
+
+ __raw_spin_lock(&data->lock);
+ entry = tracing_get_trace_entry(tr, data);
+ tracing_generic_entry_update(entry, flags);
+ entry->type = TRACE_PRINT;
+ entry->field.print.ip = ip;
+
+ write = min(len, (int)(TRACE_PRINT_BUF_SIZE-1));
+
+ memcpy(&entry->field.print.buf, trace_buf, write);
+ entry->field.print.buf[write] = 0;
+ written = write;
+
+ if (written != len)
+ entry->field.flags |= TRACE_FLAG_CONT;
+
+ while (written != len) {
+ entry = tracing_get_trace_entry(tr, data);
+
+ entry->type = TRACE_CONT;
+ write = min(len - written, (int)(TRACE_CONT_BUF_SIZE-1));
+ memcpy(&entry->cont.buf, trace_buf+written, write);
+ entry->cont.buf[write] = 0;
+ written += write;
+ }
+ __raw_spin_unlock(&data->lock);
+
+ spin_unlock(&trace_buf_lock);
+
+ out:
+ atomic_dec(&data->disabled);
+ local_irq_restore(flags);
+
+ return len;
+}
+EXPORT_SYMBOL_GPL(__ftrace_printk);
+
static int trace_alloc_page(void)
{
struct trace_array_cpu *data;
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 6ddd6a6556c..50b6d7a6f01 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -13,7 +13,9 @@ enum trace_type {
TRACE_FN,
TRACE_CTX,
TRACE_WAKE,
+ TRACE_CONT,
TRACE_STACK,
+ TRACE_PRINT,
TRACE_SPECIAL,
TRACE_MMIO_RW,
TRACE_MMIO_MAP,
@@ -61,6 +63,14 @@ struct stack_entry {
};
/*
+ * ftrace_printk entry:
+ */
+struct print_entry {
+ unsigned long ip;
+ char buf[];
+};
+
+/*
* The trace field - the most basic unit of tracing. This is what
* is printed in the end as a single line in the trace output, such as:
*
@@ -77,6 +87,7 @@ struct trace_field {
struct ctx_switch_entry ctx;
struct special_entry special;
struct stack_entry stack;
+ struct print_entry print;
struct mmiotrace_rw mmiorw;
struct mmiotrace_map mmiomap;
};
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 0911b7e073b..630715bbd57 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -9,7 +9,9 @@ static inline int trace_valid_entry(struct trace_entry *entry)
case TRACE_FN:
case TRACE_CTX:
case TRACE_WAKE:
+ case TRACE_CONT:
case TRACE_STACK:
+ case TRACE_PRINT:
case TRACE_SPECIAL:
return 1;
}
@@ -120,11 +122,11 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace,
struct trace_array *tr,
int (*func)(void))
{
- unsigned long count;
- int ret;
int save_ftrace_enabled = ftrace_enabled;
int save_tracer_enabled = tracer_enabled;
+ unsigned long count;
char *func_name;
+ int ret;
/* The ftrace test PASSED */
printk(KERN_CONT "PASSED\n");
@@ -157,6 +159,7 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace,
/* enable tracing */
tr->ctrl = 1;
trace->init(tr);
+
/* Sleep for a 1/10 of a second */
msleep(100);
@@ -212,10 +215,10 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace,
int
trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr)
{
- unsigned long count;
- int ret;
int save_ftrace_enabled = ftrace_enabled;
int save_tracer_enabled = tracer_enabled;
+ unsigned long count;
+ int ret;
/* make sure msleep has been recorded */
msleep(1);