From 80a9b64e2c156b6523e7a01f2ba6e5d86e722814 Mon Sep 17 00:00:00 2001
From: Steven Rostedt <rostedt@goodmis.org>
Date: Tue, 17 Mar 2015 10:40:38 -0400
Subject: ring-buffer: Replace this_cpu_*() with __this_cpu_*()

It has come to my attention that this_cpu_read/write are horrible on
architectures other than x86. Worse yet, they actually disable
preemption or interrupts! This caused some unexpected tracing results
on ARM.

   101.356868: preempt_count_add <-ring_buffer_lock_reserve
   101.356870: preempt_count_sub <-ring_buffer_lock_reserve

The ring_buffer_lock_reserve has recursion protection that requires
accessing a per cpu variable. But since preempt_disable() is traced, it
too got traced while accessing the variable that is suppose to prevent
recursion like this.

The generic version of this_cpu_read() and write() are:

 #define this_cpu_generic_read(pcp)					\
 ({	typeof(pcp) ret__;						\
	preempt_disable();						\
	ret__ = *this_cpu_ptr(&(pcp));					\
	preempt_enable();						\
	ret__;								\
 })

 #define this_cpu_generic_to_op(pcp, val, op)				\
 do {									\
	unsigned long flags;						\
	raw_local_irq_save(flags);					\
	*__this_cpu_ptr(&(pcp)) op val;					\
	raw_local_irq_restore(flags);					\
 } while (0)

Which is unacceptable for locations that know they are within preempt
disabled or interrupt disabled locations.

Paul McKenney stated that __this_cpu_() versions produce much better code on
other architectures than this_cpu_() does, if we know that the call is done in
a preempt disabled location.

I also changed the recursive_unlock() to use two local variables instead
of accessing the per_cpu variable twice.

Link: http://lkml.kernel.org/r/20150317114411.GE3589@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/20150317104038.312e73d1@gandalf.local.home

Cc: stable@vger.kernel.org
Acked-by: Christoph Lameter <cl@linux.com>
Reported-by: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
Tested-by: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ring_buffer.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

(limited to 'kernel')

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 5040d44fe5a3..922048a0f7ea 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2679,7 +2679,7 @@ static DEFINE_PER_CPU(unsigned int, current_context);
 
 static __always_inline int trace_recursive_lock(void)
 {
-	unsigned int val = this_cpu_read(current_context);
+	unsigned int val = __this_cpu_read(current_context);
 	int bit;
 
 	if (in_interrupt()) {
@@ -2696,18 +2696,17 @@ static __always_inline int trace_recursive_lock(void)
 		return 1;
 
 	val |= (1 << bit);
-	this_cpu_write(current_context, val);
+	__this_cpu_write(current_context, val);
 
 	return 0;
 }
 
 static __always_inline void trace_recursive_unlock(void)
 {
-	unsigned int val = this_cpu_read(current_context);
+	unsigned int val = __this_cpu_read(current_context);
 
-	val--;
-	val &= this_cpu_read(current_context);
-	this_cpu_write(current_context, val);
+	val &= val & (val - 1);
+	__this_cpu_write(current_context, val);
 }
 
 #else
-- 
cgit v1.2.3


From bbedb179944c29e5e449603163eec9951116fe39 Mon Sep 17 00:00:00 2001
From: Scott Wood <scottwood@freescale.com>
Date: Wed, 11 Mar 2015 22:13:57 -0500
Subject: tracing: %pF is only for function pointers

Use %pS for actual addresses, otherwise you'll get bad output
on arches like ppc64 where %pF expects a function descriptor.

Link: http://lkml.kernel.org/r/1426130037-17956-22-git-send-email-scottwood@freescale.com

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/trace/events/btrfs.h       |  4 ++--
 include/trace/events/ext3.h        |  2 +-
 include/trace/events/ext4.h        |  6 +++---
 include/trace/events/module.h      |  4 ++--
 include/trace/events/random.h      | 10 +++++-----
 kernel/trace/trace_entries.h       |  6 +++---
 tools/lib/traceevent/event-parse.c |  2 +-
 7 files changed, 17 insertions(+), 17 deletions(-)

(limited to 'kernel')

diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h
index 1faecea101f3..572e6503394a 100644
--- a/include/trace/events/btrfs.h
+++ b/include/trace/events/btrfs.h
@@ -962,7 +962,7 @@ TRACE_EVENT(alloc_extent_state,
 		__entry->ip	= IP
 	),
 
-	TP_printk("state=%p; mask = %s; caller = %pF", __entry->state,
+	TP_printk("state=%p; mask = %s; caller = %pS", __entry->state,
 		  show_gfp_flags(__entry->mask), (void *)__entry->ip)
 );
 
@@ -982,7 +982,7 @@ TRACE_EVENT(free_extent_state,
 		__entry->ip = IP
 	),
 
-	TP_printk(" state=%p; caller = %pF", __entry->state,
+	TP_printk(" state=%p; caller = %pS", __entry->state,
 		  (void *)__entry->ip)
 );
 
diff --git a/include/trace/events/ext3.h b/include/trace/events/ext3.h
index 6797b9de90ed..7f20707849bb 100644
--- a/include/trace/events/ext3.h
+++ b/include/trace/events/ext3.h
@@ -144,7 +144,7 @@ TRACE_EVENT(ext3_mark_inode_dirty,
 		__entry->ip	= IP;
 	),
 
-	TP_printk("dev %d,%d ino %lu caller %pF",
+	TP_printk("dev %d,%d ino %lu caller %pS",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
 		  (unsigned long) __entry->ino, (void *)__entry->ip)
 );
diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h
index 6e5abd6d38a2..47fca36ee426 100644
--- a/include/trace/events/ext4.h
+++ b/include/trace/events/ext4.h
@@ -240,7 +240,7 @@ TRACE_EVENT(ext4_mark_inode_dirty,
 		__entry->ip	= IP;
 	),
 
-	TP_printk("dev %d,%d ino %lu caller %pF",
+	TP_printk("dev %d,%d ino %lu caller %pS",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
 		  (unsigned long) __entry->ino, (void *)__entry->ip)
 );
@@ -1762,7 +1762,7 @@ TRACE_EVENT(ext4_journal_start,
 		__entry->rsv_blocks	 = rsv_blocks;
 	),
 
-	TP_printk("dev %d,%d blocks, %d rsv_blocks, %d caller %pF",
+	TP_printk("dev %d,%d blocks, %d rsv_blocks, %d caller %pS",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
 		  __entry->blocks, __entry->rsv_blocks, (void *)__entry->ip)
 );
@@ -1784,7 +1784,7 @@ TRACE_EVENT(ext4_journal_start_reserved,
 		__entry->blocks		 = blocks;
 	),
 
-	TP_printk("dev %d,%d blocks, %d caller %pF",
+	TP_printk("dev %d,%d blocks, %d caller %pS",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
 		  __entry->blocks, (void *)__entry->ip)
 );
diff --git a/include/trace/events/module.h b/include/trace/events/module.h
index 81c4c183d348..28c45997e451 100644
--- a/include/trace/events/module.h
+++ b/include/trace/events/module.h
@@ -84,7 +84,7 @@ DECLARE_EVENT_CLASS(module_refcnt,
 		__assign_str(name, mod->name);
 	),
 
-	TP_printk("%s call_site=%pf refcnt=%d",
+	TP_printk("%s call_site=%ps refcnt=%d",
 		  __get_str(name), (void *)__entry->ip, __entry->refcnt)
 );
 
@@ -121,7 +121,7 @@ TRACE_EVENT(module_request,
 		__assign_str(name, name);
 	),
 
-	TP_printk("%s wait=%d call_site=%pf",
+	TP_printk("%s wait=%d call_site=%ps",
 		  __get_str(name), (int)__entry->wait, (void *)__entry->ip)
 );
 
diff --git a/include/trace/events/random.h b/include/trace/events/random.h
index 805af6db41cc..4684de344c5d 100644
--- a/include/trace/events/random.h
+++ b/include/trace/events/random.h
@@ -22,7 +22,7 @@ TRACE_EVENT(add_device_randomness,
 		__entry->IP		= IP;
 	),
 
-	TP_printk("bytes %d caller %pF",
+	TP_printk("bytes %d caller %pS",
 		__entry->bytes, (void *)__entry->IP)
 );
 
@@ -43,7 +43,7 @@ DECLARE_EVENT_CLASS(random__mix_pool_bytes,
 		__entry->IP		= IP;
 	),
 
-	TP_printk("%s pool: bytes %d caller %pF",
+	TP_printk("%s pool: bytes %d caller %pS",
 		  __entry->pool_name, __entry->bytes, (void *)__entry->IP)
 );
 
@@ -82,7 +82,7 @@ TRACE_EVENT(credit_entropy_bits,
 	),
 
 	TP_printk("%s pool: bits %d entropy_count %d entropy_total %d "
-		  "caller %pF", __entry->pool_name, __entry->bits,
+		  "caller %pS", __entry->pool_name, __entry->bits,
 		  __entry->entropy_count, __entry->entropy_total,
 		  (void *)__entry->IP)
 );
@@ -207,7 +207,7 @@ DECLARE_EVENT_CLASS(random__get_random_bytes,
 		__entry->IP		= IP;
 	),
 
-	TP_printk("nbytes %d caller %pF", __entry->nbytes, (void *)__entry->IP)
+	TP_printk("nbytes %d caller %pS", __entry->nbytes, (void *)__entry->IP)
 );
 
 DEFINE_EVENT(random__get_random_bytes, get_random_bytes,
@@ -242,7 +242,7 @@ DECLARE_EVENT_CLASS(random__extract_entropy,
 		__entry->IP		= IP;
 	),
 
-	TP_printk("%s pool: nbytes %d entropy_count %d caller %pF",
+	TP_printk("%s pool: nbytes %d entropy_count %d caller %pS",
 		  __entry->pool_name, __entry->nbytes, __entry->entropy_count,
 		  (void *)__entry->IP)
 );
diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h
index e2d027ac66a2..ee7b94a4810a 100644
--- a/kernel/trace/trace_entries.h
+++ b/kernel/trace/trace_entries.h
@@ -223,7 +223,7 @@ FTRACE_ENTRY(bprint, bprint_entry,
 		__dynamic_array(	u32,	buf	)
 	),
 
-	F_printk("%pf: %s",
+	F_printk("%ps: %s",
 		 (void *)__entry->ip, __entry->fmt),
 
 	FILTER_OTHER
@@ -238,7 +238,7 @@ FTRACE_ENTRY(print, print_entry,
 		__dynamic_array(	char,	buf	)
 	),
 
-	F_printk("%pf: %s",
+	F_printk("%ps: %s",
 		 (void *)__entry->ip, __entry->buf),
 
 	FILTER_OTHER
@@ -253,7 +253,7 @@ FTRACE_ENTRY(bputs, bputs_entry,
 		__field(	const char *,	str	)
 	),
 
-	F_printk("%pf: %s",
+	F_printk("%ps: %s",
 		 (void *)__entry->ip, __entry->str),
 
 	FILTER_OTHER
diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index afe20ed9fac8..2c0bd8f2aad0 100644
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -3976,7 +3976,7 @@ static struct print_arg *make_bprint_args(char *fmt, void *data, int size, struc
 	if (asprintf(&arg->atom.atom, "%lld", ip) < 0)
 		goto out_free;
 
-	/* skip the first "%pf: " */
+	/* skip the first "%ps: " */
 	for (ptr = fmt + 5, bptr = data + field->offset;
 	     bptr < data + size && *ptr; ptr++) {
 		int ls = 0;
-- 
cgit v1.2.3


From 754cb0071a5c9576ccfa6523969ef6a2f6a71676 Mon Sep 17 00:00:00 2001
From: He Kuang <hekuang@huawei.com>
Date: Tue, 3 Mar 2015 15:21:33 +0800
Subject: tracing: remove ftrace:function TRACE_EVENT_FL_USE_CALL_FILTER flag

TRACE_EVENT_FL_USE_CALL_FILTER flag in ftrace:functon event can be
removed. This flag was first introduced in commit
f306cc82a93d ("tracing: Update event filters for multibuffer").

Now, the only place uses this flag is ftrace:function, but the filter of
ftrace:function has a different code path with events/syscalls and
events/tracepoints. It uses ftrace_filter_write() and perf's
ftrace_profile_set_filter() to set the filter, the functionality of file
'tracing/events/ftrace/function/filter' is bypassed in function
init_pred(), in which case, neither call->filter nor file->filter is
used.

So we can safely remove TRACE_EVENT_FL_USE_CALL_FILTER flag from
ftrace:function events.

Link: http://lkml.kernel.org/r/1425367294-27852-1-git-send-email-hekuang@huawei.com

Signed-off-by: He Kuang <hekuang@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_export.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'kernel')

diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c
index 12e2b99be862..174a6a71146c 100644
--- a/kernel/trace/trace_export.c
+++ b/kernel/trace/trace_export.c
@@ -177,7 +177,7 @@ struct ftrace_event_call __used event_##call = {			\
 	},								\
 	.event.type		= etype,				\
 	.print_fmt		= print,				\
-	.flags			= TRACE_EVENT_FL_IGNORE_ENABLE | TRACE_EVENT_FL_USE_CALL_FILTER, \
+	.flags			= TRACE_EVENT_FL_IGNORE_ENABLE,		\
 };									\
 struct ftrace_event_call __used						\
 __attribute__((section("_ftrace_events"))) *__event_##call = &event_##call;
-- 
cgit v1.2.3


From d9a16d3ab8770357015c85a07387f1d2676a4773 Mon Sep 17 00:00:00 2001
From: Stephen Rothwell <sfr@canb.auug.org.au>
Date: Thu, 12 Mar 2015 16:58:34 +1100
Subject: trace: Don't use __weak in header files

The commit that added a check for this to checkpatch says:

"Using weak declarations can have unintended link defects.  The __weak on
the declaration causes non-weak definitions to become weak."

In this case, when a PowerPC kernel is built with CONFIG_KPROBE_EVENT
but not CONFIG_UPROBE_EVENT, it generates the following warning:

WARNING: 1 bad relocations
c0000000014f2190 R_PPC64_ADDR64    uprobes_fetch_type_table

This is fixed by passing the fetch_table arrays to
traceprobe_parse_probe_arg() which also means that they can never be NULL.

Link: http://lkml.kernel.org/r/20150312165834.4482cb48@canb.auug.org.au

Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_kprobe.c |  5 +++--
 kernel/trace/trace_probe.c  | 19 +++++++------------
 kernel/trace/trace_probe.h  | 10 ++--------
 kernel/trace/trace_uprobe.c |  5 +++--
 4 files changed, 15 insertions(+), 24 deletions(-)

(limited to 'kernel')

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index d73f565b4e06..f34c3ad1b5f4 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -250,7 +250,7 @@ DEFINE_FETCH_symbol(string_size)
 #define fetch_file_offset_string_size	NULL
 
 /* Fetch type information table */
-const struct fetch_type kprobes_fetch_type_table[] = {
+static const struct fetch_type kprobes_fetch_type_table[] = {
 	/* Special types */
 	[FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
 					sizeof(u32), 1, "__data_loc char[]"),
@@ -760,7 +760,8 @@ static int create_trace_kprobe(int argc, char **argv)
 
 		/* Parse fetch argument */
 		ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
-						is_return, true);
+						is_return, true,
+						kprobes_fetch_type_table);
 		if (ret) {
 			pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
 			goto error;
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index b983b2fd2ca1..1769a81da8a7 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -356,17 +356,14 @@ static int parse_probe_vars(char *arg, const struct fetch_type *t,
 
 /* Recursive argument parser */
 static int parse_probe_arg(char *arg, const struct fetch_type *t,
-		     struct fetch_param *f, bool is_return, bool is_kprobe)
+		     struct fetch_param *f, bool is_return, bool is_kprobe,
+		     const struct fetch_type *ftbl)
 {
-	const struct fetch_type *ftbl;
 	unsigned long param;
 	long offset;
 	char *tmp;
 	int ret = 0;
 
-	ftbl = is_kprobe ? kprobes_fetch_type_table : uprobes_fetch_type_table;
-	BUG_ON(ftbl == NULL);
-
 	switch (arg[0]) {
 	case '$':
 		ret = parse_probe_vars(arg + 1, t, f, is_return, is_kprobe);
@@ -447,7 +444,7 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t,
 			dprm->fetch_size = get_fetch_size_function(t,
 							dprm->fetch, ftbl);
 			ret = parse_probe_arg(arg, t2, &dprm->orig, is_return,
-							is_kprobe);
+							is_kprobe, ftbl);
 			if (ret)
 				kfree(dprm);
 			else {
@@ -505,15 +502,12 @@ static int __parse_bitfield_probe_arg(const char *bf,
 
 /* String length checking wrapper */
 int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
-		struct probe_arg *parg, bool is_return, bool is_kprobe)
+		struct probe_arg *parg, bool is_return, bool is_kprobe,
+		const struct fetch_type *ftbl)
 {
-	const struct fetch_type *ftbl;
 	const char *t;
 	int ret;
 
-	ftbl = is_kprobe ? kprobes_fetch_type_table : uprobes_fetch_type_table;
-	BUG_ON(ftbl == NULL);
-
 	if (strlen(arg) > MAX_ARGSTR_LEN) {
 		pr_info("Argument is too long.: %s\n",  arg);
 		return -ENOSPC;
@@ -535,7 +529,8 @@ int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
 	}
 	parg->offset = *size;
 	*size += parg->type->size;
-	ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return, is_kprobe);
+	ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return,
+			      is_kprobe, ftbl);
 
 	if (ret >= 0 && t != NULL)
 		ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 4f815fbce16d..e30f6cce4af6 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -229,13 +229,6 @@ ASSIGN_FETCH_FUNC(file_offset, ftype),			\
 #define FETCH_TYPE_STRING	0
 #define FETCH_TYPE_STRSIZE	1
 
-/*
- * Fetch type information table.
- * It's declared as a weak symbol due to conditional compilation.
- */
-extern __weak const struct fetch_type kprobes_fetch_type_table[];
-extern __weak const struct fetch_type uprobes_fetch_type_table[];
-
 #ifdef CONFIG_KPROBE_EVENT
 struct symbol_cache;
 unsigned long update_symbol_cache(struct symbol_cache *sc);
@@ -333,7 +326,8 @@ find_event_file_link(struct trace_probe *tp, struct ftrace_event_file *file)
 }
 
 extern int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
-		   struct probe_arg *parg, bool is_return, bool is_kprobe);
+		   struct probe_arg *parg, bool is_return, bool is_kprobe,
+		   const struct fetch_type *ftbl);
 
 extern int traceprobe_conflict_field_name(const char *name,
 			       struct probe_arg *args, int narg);
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 7dc1c8abecd6..74865465e0b7 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -196,7 +196,7 @@ DEFINE_FETCH_file_offset(string)
 DEFINE_FETCH_file_offset(string_size)
 
 /* Fetch type information table */
-const struct fetch_type uprobes_fetch_type_table[] = {
+static const struct fetch_type uprobes_fetch_type_table[] = {
 	/* Special types */
 	[FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
 					sizeof(u32), 1, "__data_loc char[]"),
@@ -535,7 +535,8 @@ static int create_trace_uprobe(int argc, char **argv)
 
 		/* Parse fetch argument */
 		ret = traceprobe_parse_probe_arg(arg, &tu->tp.size, parg,
-						 is_return, false);
+						 is_return, false,
+						 uprobes_fetch_type_table);
 		if (ret) {
 			pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
 			goto error;
-- 
cgit v1.2.3


From d631c8cceb1d1d06f372878935949d421585186b Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Fri, 27 Mar 2015 17:39:49 -0400
Subject: ring-buffer: Remove duplicate use of '&' in recursive code

A clean up of the recursive protection code changed

  val = this_cpu_read(current_context);
  val--;
  val &= this_cpu_read(current_context);

to

  val = this_cpu_read(current_context);
  val &= val & (val - 1);

Which has a duplicate use of '&' as the above is the same as

  val = val & (val - 1);

Actually, it would be best to remove that line altogether and
just add it to where it is used.

And Christoph even mentioned that it can be further compacted to
just a single line:

  __this_cpu_and(current_context, __this_cpu_read(current_context) - 1);

Link: http://lkml.kernel.org/alpine.DEB.2.11.1503271423580.23114@gentwo.org

Suggested-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ring_buffer.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

(limited to 'kernel')

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 922048a0f7ea..0315d43176d8 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2703,10 +2703,7 @@ static __always_inline int trace_recursive_lock(void)
 
 static __always_inline void trace_recursive_unlock(void)
 {
-	unsigned int val = __this_cpu_read(current_context);
-
-	val &= val & (val - 1);
-	__this_cpu_write(current_context, val);
+	__this_cpu_and(current_context, __this_cpu_read(current_context) - 1);
 }
 
 #else
-- 
cgit v1.2.3


From 00ccbf2f5b7580cd7dcdaeda84828d14f0cba3c9 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Thu, 19 Feb 2015 15:56:14 +0100
Subject: ftrace/x86: Let dynamic trampolines call ops->func even for dynamic
 fops

Dynamically allocated trampolines call ftrace_ops_get_func to get the
function which they should call. For dynamic fops (FTRACE_OPS_FL_DYNAMIC
flag is set) ftrace_ops_list_func is always returned. This is reasonable
for static trampolines but goes against the main advantage of dynamic
ones, that is avoidance of going through the list of all registered
callbacks for functions that are only being traced by a single callback.

We can fix it by returning ops->func (or recursion safe version) from
ftrace_ops_get_func whenever it is possible for dynamic trampolines.

Note that dynamic trampolines are not allowed for dynamic fops if
CONFIG_PREEMPT=y.

Link: http://lkml.kernel.org/r/alpine.LNX.2.00.1501291023000.25445@pobox.suse.cz
Link: http://lkml.kernel.org/r/1424357773-13536-1-git-send-email-mbenes@suse.cz

Reported-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

(limited to 'kernel')

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 4f228024055b..d01d238d8ef4 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -249,6 +249,19 @@ static void update_function_graph_func(void);
 static inline void update_function_graph_func(void) { }
 #endif
 
+
+static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
+{
+	/*
+	 * If this is a dynamic ops or we force list func,
+	 * then it needs to call the list anyway.
+	 */
+	if (ops->flags & FTRACE_OPS_FL_DYNAMIC || FTRACE_FORCE_LIST_FUNC)
+		return ftrace_ops_list_func;
+
+	return ftrace_ops_get_func(ops);
+}
+
 static void update_ftrace_function(void)
 {
 	ftrace_func_t func;
@@ -270,7 +283,7 @@ static void update_ftrace_function(void)
 	 * then have the mcount trampoline call the function directly.
 	 */
 	} else if (ftrace_ops_list->next == &ftrace_list_end) {
-		func = ftrace_ops_get_func(ftrace_ops_list);
+		func = ftrace_ops_get_list_func(ftrace_ops_list);
 
 	} else {
 		/* Just use the default ftrace_ops */
@@ -5208,13 +5221,6 @@ static void ftrace_ops_recurs_func(unsigned long ip, unsigned long parent_ip,
  */
 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
 {
-	/*
-	 * If this is a dynamic ops or we force list func,
-	 * then it needs to call the list anyway.
-	 */
-	if (ops->flags & FTRACE_OPS_FL_DYNAMIC || FTRACE_FORCE_LIST_FUNC)
-		return ftrace_ops_list_func;
-
 	/*
 	 * If the func handles its own recursion, call it directly.
 	 * Otherwise call the recursion protected function that
-- 
cgit v1.2.3


From 0c564a538aa934ad15b2145aaf8b64f3feb0be63 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Tue, 24 Mar 2015 17:58:09 -0400
Subject: tracing: Add TRACE_DEFINE_ENUM() macro to map enums to their values

Several tracepoints use the helper functions __print_symbolic() or
__print_flags() and pass in enums that do the mapping between the
binary data stored and the value to print. This works well for reading
the ASCII trace files, but when the data is read via userspace tools
such as perf and trace-cmd, the conversion of the binary value to a
human string format is lost if an enum is used, as userspace does not
have access to what the ENUM is.

For example, the tracepoint trace_tlb_flush() has:

 __print_symbolic(REC->reason,
    { TLB_FLUSH_ON_TASK_SWITCH, "flush on task switch" },
    { TLB_REMOTE_SHOOTDOWN, "remote shootdown" },
    { TLB_LOCAL_SHOOTDOWN, "local shootdown" },
    { TLB_LOCAL_MM_SHOOTDOWN, "local mm shootdown" })

Which maps the enum values to the strings they represent. But perf and
trace-cmd do no know what value TLB_LOCAL_MM_SHOOTDOWN is, and would
not be able to map it.

With TRACE_DEFINE_ENUM(), developers can place these in the event header
files and ftrace will convert the enums to their values:

By adding:

 TRACE_DEFINE_ENUM(TLB_FLUSH_ON_TASK_SWITCH);
 TRACE_DEFINE_ENUM(TLB_REMOTE_SHOOTDOWN);
 TRACE_DEFINE_ENUM(TLB_LOCAL_SHOOTDOWN);
 TRACE_DEFINE_ENUM(TLB_LOCAL_MM_SHOOTDOWN);

 $ cat /sys/kernel/debug/tracing/events/tlb/tlb_flush/format
[...]
 __print_symbolic(REC->reason,
    { 0, "flush on task switch" },
    { 1, "remote shootdown" },
    { 2, "local shootdown" },
    { 3, "local mm shootdown" })

The above is what userspace expects to see, and tools do not need to
be modified to parse them.

Link: http://lkml.kernel.org/r/20150403013802.220157513@goodmis.org

Cc: Guilherme Cox <cox@computer.org>
Cc: Tony Luck <tony.luck@gmail.com>
Cc: Xie XiuQi <xiexiuqi@huawei.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/asm-generic/vmlinux.lds.h |   5 +-
 include/linux/ftrace_event.h      |   2 +-
 include/linux/tracepoint.h        |   8 +++
 include/trace/ftrace.h            |  22 ++++++-
 kernel/trace/trace.c              |  26 ++++++++-
 kernel/trace/trace.h              |   2 +
 kernel/trace/trace_events.c       | 119 ++++++++++++++++++++++++++++++++++++++
 7 files changed, 178 insertions(+), 6 deletions(-)

(limited to 'kernel')

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index ac78910d7416..f8e8b34dc427 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -124,7 +124,10 @@
 #define FTRACE_EVENTS()	. = ALIGN(8);					\
 			VMLINUX_SYMBOL(__start_ftrace_events) = .;	\
 			*(_ftrace_events)				\
-			VMLINUX_SYMBOL(__stop_ftrace_events) = .;
+			VMLINUX_SYMBOL(__stop_ftrace_events) = .;	\
+			VMLINUX_SYMBOL(__start_ftrace_enum_maps) = .;	\
+			*(_ftrace_enum_map)				\
+			VMLINUX_SYMBOL(__stop_ftrace_enum_maps) = .;
 #else
 #define FTRACE_EVENTS()
 #endif
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 62b8fac7ded5..112cf49d9576 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -285,7 +285,7 @@ struct ftrace_event_call {
 		struct tracepoint	*tp;
 	};
 	struct trace_event	event;
-	const char		*print_fmt;
+	char			*print_fmt;
 	struct event_filter	*filter;
 	void			*mod;
 	void			*data;
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index c72851328ca9..a5f7f3ecafa3 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -36,6 +36,12 @@ struct tracepoint {
 	struct tracepoint_func __rcu *funcs;
 };
 
+struct trace_enum_map {
+	const char		*system;
+	const char		*enum_string;
+	unsigned long		enum_value;
+};
+
 extern int
 tracepoint_probe_register(struct tracepoint *tp, void *probe, void *data);
 extern int
@@ -87,6 +93,8 @@ extern void syscall_unregfunc(void);
 
 #define PARAMS(args...) args
 
+#define TRACE_DEFINE_ENUM(x)
+
 #endif /* _LINUX_TRACEPOINT_H */
 
 /*
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 2f9b95b6d3fb..37d4b10b111d 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -33,6 +33,19 @@
 
 TRACE_MAKE_SYSTEM_STR();
 
+#undef TRACE_DEFINE_ENUM
+#define TRACE_DEFINE_ENUM(a)				\
+	static struct trace_enum_map __used __initdata	\
+	__##TRACE_SYSTEM##_##a =			\
+	{						\
+		.system = TRACE_SYSTEM_STRING,		\
+		.enum_string = #a,			\
+		.enum_value = a				\
+	};						\
+	static struct trace_enum_map __used		\
+	__attribute__((section("_ftrace_enum_map")))	\
+	*TRACE_SYSTEM##_##a = &__##TRACE_SYSTEM##_##a
+
 /*
  * DECLARE_EVENT_CLASS can be used to add a generic function
  * handlers for events. That is, if all events have the same
@@ -136,6 +149,9 @@ TRACE_MAKE_SYSTEM_STR();
  * The size of an array is also encoded, in the higher 16 bits of <item>.
  */
 
+#undef TRACE_DEFINE_ENUM
+#define TRACE_DEFINE_ENUM(a)
+
 #undef __field
 #define __field(type, item)
 
@@ -553,7 +569,7 @@ static inline notrace int ftrace_get_offsets_##call(			\
  *	.trace			= ftrace_raw_output_<call>, <-- stage 2
  * };
  *
- * static const char print_fmt_<call>[] = <TP_printk>;
+ * static char print_fmt_<call>[] = <TP_printk>;
  *
  * static struct ftrace_event_class __used event_class_<template> = {
  *	.system			= "<system>",
@@ -704,7 +720,7 @@ static inline void ftrace_test_probe_##call(void)			\
 #undef DECLARE_EVENT_CLASS
 #define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print)	\
 _TRACE_PERF_PROTO(call, PARAMS(proto));					\
-static const char print_fmt_##call[] = print;				\
+static char print_fmt_##call[] = print;					\
 static struct ftrace_event_class __used __refdata event_class_##call = { \
 	.system			= TRACE_SYSTEM_STRING,			\
 	.define_fields		= ftrace_define_fields_##call,		\
@@ -733,7 +749,7 @@ __attribute__((section("_ftrace_events"))) *__event_##call = &event_##call
 #undef DEFINE_EVENT_PRINT
 #define DEFINE_EVENT_PRINT(template, call, proto, args, print)		\
 									\
-static const char print_fmt_##call[] = print;				\
+static char print_fmt_##call[] = print;					\
 									\
 static struct ftrace_event_call __used event_##call = {			\
 	.class			= &event_class_##template,		\
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 62c6506d663f..ebf49649534c 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3908,6 +3908,20 @@ static const struct file_operations tracing_saved_cmdlines_size_fops = {
 	.write		= tracing_saved_cmdlines_size_write,
 };
 
+static void
+trace_insert_enum_map(struct trace_enum_map **start, struct trace_enum_map **stop)
+{
+	struct trace_enum_map **map;
+	int len = stop - start;
+
+	if (len <= 0)
+		return;
+
+	map = start;
+
+	trace_event_enum_update(map, len);
+}
+
 static ssize_t
 tracing_set_trace_read(struct file *filp, char __user *ubuf,
 		       size_t cnt, loff_t *ppos)
@@ -6542,6 +6556,14 @@ struct dentry *tracing_init_dentry(void)
 	return tr->dir;
 }
 
+extern struct trace_enum_map *__start_ftrace_enum_maps[];
+extern struct trace_enum_map *__stop_ftrace_enum_maps[];
+
+static void __init trace_enum_init(void)
+{
+	trace_insert_enum_map(__start_ftrace_enum_maps, __stop_ftrace_enum_maps);
+}
+
 static __init int tracer_init_debugfs(void)
 {
 	struct dentry *d_tracer;
@@ -6566,6 +6588,8 @@ static __init int tracer_init_debugfs(void)
 	trace_create_file("saved_cmdlines_size", 0644, d_tracer,
 			  NULL, &tracing_saved_cmdlines_size_fops);
 
+	trace_enum_init();
+
 #ifdef CONFIG_DYNAMIC_FTRACE
 	trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
 			&ftrace_update_tot_cnt, &tracing_dyn_info_fops);
@@ -6888,7 +6912,7 @@ void __init trace_init(void)
 			tracepoint_printk = 0;
 	}
 	tracer_alloc_buffers();
-	trace_event_init();	
+	trace_event_init();
 }
 
 __init static int clear_boot_tracer(void)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index dd8205a35760..b48d4b08f691 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1309,8 +1309,10 @@ static inline void init_ftrace_syscalls(void) { }
 
 #ifdef CONFIG_EVENT_TRACING
 void trace_event_init(void);
+void trace_event_enum_update(struct trace_enum_map **map, int len);
 #else
 static inline void __init trace_event_init(void) { }
+static inlin void trace_event_enum_update(struct trace_enum_map **map, int len) { }
 #endif
 
 extern struct trace_iterator *tracepoint_print_iter;
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index db54dda10ccc..fc58c50fbf01 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1704,6 +1704,125 @@ __register_event(struct ftrace_event_call *call, struct module *mod)
 	return 0;
 }
 
+static char *enum_replace(char *ptr, struct trace_enum_map *map, int len)
+{
+	int rlen;
+	int elen;
+
+	/* Find the length of the enum value as a string */
+	elen = snprintf(ptr, 0, "%ld", map->enum_value);
+	/* Make sure there's enough room to replace the string with the value */
+	if (len < elen)
+		return NULL;
+
+	snprintf(ptr, elen + 1, "%ld", map->enum_value);
+
+	/* Get the rest of the string of ptr */
+	rlen = strlen(ptr + len);
+	memmove(ptr + elen, ptr + len, rlen);
+	/* Make sure we end the new string */
+	ptr[elen + rlen] = 0;
+
+	return ptr + elen;
+}
+
+static void update_event_printk(struct ftrace_event_call *call,
+				struct trace_enum_map *map)
+{
+	char *ptr;
+	int quote = 0;
+	int len = strlen(map->enum_string);
+
+	for (ptr = call->print_fmt; *ptr; ptr++) {
+		if (*ptr == '\\') {
+			ptr++;
+			/* paranoid */
+			if (!*ptr)
+				break;
+			continue;
+		}
+		if (*ptr == '"') {
+			quote ^= 1;
+			continue;
+		}
+		if (quote)
+			continue;
+		if (isdigit(*ptr)) {
+			/* skip numbers */
+			do {
+				ptr++;
+				/* Check for alpha chars like ULL */
+			} while (isalnum(*ptr));
+			/*
+			 * A number must have some kind of delimiter after
+			 * it, and we can ignore that too.
+			 */
+			continue;
+		}
+		if (isalpha(*ptr) || *ptr == '_') {
+			if (strncmp(map->enum_string, ptr, len) == 0 &&
+			    !isalnum(ptr[len]) && ptr[len] != '_') {
+				ptr = enum_replace(ptr, map, len);
+				/* Hmm, enum string smaller than value */
+				if (WARN_ON_ONCE(!ptr))
+					return;
+				/*
+				 * No need to decrement here, as enum_replace()
+				 * returns the pointer to the character passed
+				 * the enum, and two enums can not be placed
+				 * back to back without something in between.
+				 * We can skip that something in between.
+				 */
+				continue;
+			}
+		skip_more:
+			do {
+				ptr++;
+			} while (isalnum(*ptr) || *ptr == '_');
+			/*
+			 * If what comes after this variable is a '.' or
+			 * '->' then we can continue to ignore that string.
+			 */
+			if (*ptr == '.' || (ptr[0] == '-' && ptr[1] == '>')) {
+				ptr += *ptr == '.' ? 1 : 2;
+				goto skip_more;
+			}
+			/*
+			 * Once again, we can skip the delimiter that came
+			 * after the string.
+			 */
+			continue;
+		}
+	}
+}
+
+void trace_event_enum_update(struct trace_enum_map **map, int len)
+{
+	struct ftrace_event_call *call, *p;
+	const char *last_system = NULL;
+	int last_i;
+	int i;
+
+	down_write(&trace_event_sem);
+	list_for_each_entry_safe(call, p, &ftrace_events, list) {
+		/* events are usually grouped together with systems */
+		if (!last_system || call->class->system != last_system) {
+			last_i = 0;
+			last_system = call->class->system;
+		}
+
+		for (i = last_i; i < len; i++) {
+			if (call->class->system == map[i]->system) {
+				/* Save the first system if need be */
+				if (!last_i)
+					last_i = i;
+				update_event_printk(call, map[i]);
+			}
+		}
+	}
+	up_write(&trace_event_sem);
+}
+
 static struct ftrace_event_file *
 trace_create_new_event(struct ftrace_event_call *call,
 		       struct trace_array *tr)
-- 
cgit v1.2.3


From 3673b8e4ce7237160fa31ee8d7e94a4d5a9976a1 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Wed, 25 Mar 2015 15:44:21 -0400
Subject: tracing: Allow for modules to convert their enums to values

Update the infrastructure such that modules that declare TRACE_DEFINE_ENUM()
will have those enums converted into their values in the tracepoint
print fmt strings.

Link: http://lkml.kernel.org/r/87vbhjp74q.fsf@rustcorp.com.au

Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/linux/module.h      |  2 ++
 kernel/module.c             |  3 +++
 kernel/trace/trace.c        | 49 +++++++++++++++++++++++++++++++++++++++++----
 kernel/trace/trace_events.c |  2 +-
 4 files changed, 51 insertions(+), 5 deletions(-)

(limited to 'kernel')

diff --git a/include/linux/module.h b/include/linux/module.h
index 42999fe2dbd0..53dc41dd5c62 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -338,6 +338,8 @@ struct module {
 #ifdef CONFIG_EVENT_TRACING
 	struct ftrace_event_call **trace_events;
 	unsigned int num_trace_events;
+	struct trace_enum_map **trace_enums;
+	unsigned int num_trace_enums;
 #endif
 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 	unsigned int num_ftrace_callsites;
diff --git a/kernel/module.c b/kernel/module.c
index b3d634ed06c9..d8f8ab271c2b 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2753,6 +2753,9 @@ static int find_module_sections(struct module *mod, struct load_info *info)
 	mod->trace_events = section_objs(info, "_ftrace_events",
 					 sizeof(*mod->trace_events),
 					 &mod->num_trace_events);
+	mod->trace_enums = section_objs(info, "_ftrace_enum_map",
+					sizeof(*mod->trace_enums),
+					&mod->num_trace_enums);
 #endif
 #ifdef CONFIG_TRACING
 	mod->trace_bprintk_fmt_start = section_objs(info, "__trace_printk_fmt",
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index ebf49649534c..28e6654e640d 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3908,11 +3908,9 @@ static const struct file_operations tracing_saved_cmdlines_size_fops = {
 	.write		= tracing_saved_cmdlines_size_write,
 };
 
-static void
-trace_insert_enum_map(struct trace_enum_map **start, struct trace_enum_map **stop)
+static void trace_insert_enum_map(struct trace_enum_map **start, int len)
 {
 	struct trace_enum_map **map;
-	int len = stop - start;
 
 	if (len <= 0)
 		return;
@@ -6561,9 +6559,48 @@ extern struct trace_enum_map *__stop_ftrace_enum_maps[];
 
 static void __init trace_enum_init(void)
 {
-	trace_insert_enum_map(__start_ftrace_enum_maps, __stop_ftrace_enum_maps);
+	int len;
+
+	len = __stop_ftrace_enum_maps - __start_ftrace_enum_maps;
+	trace_insert_enum_map(__start_ftrace_enum_maps, len);
+}
+
+#ifdef CONFIG_MODULES
+static void trace_module_add_enums(struct module *mod)
+{
+	if (!mod->num_trace_enums)
+		return;
+
+	/*
+	 * Modules with bad taint do not have events created, do
+	 * not bother with enums either.
+	 */
+	if (trace_module_has_bad_taint(mod))
+		return;
+
+	trace_insert_enum_map(mod->trace_enums, mod->num_trace_enums);
+}
+
+static int trace_module_notify(struct notifier_block *self,
+			       unsigned long val, void *data)
+{
+	struct module *mod = data;
+
+	switch (val) {
+	case MODULE_STATE_COMING:
+		trace_module_add_enums(mod);
+		break;
+	}
+
+	return 0;
 }
 
+static struct notifier_block trace_module_nb = {
+	.notifier_call = trace_module_notify,
+	.priority = 0,
+};
+#endif
+
 static __init int tracer_init_debugfs(void)
 {
 	struct dentry *d_tracer;
@@ -6590,6 +6627,10 @@ static __init int tracer_init_debugfs(void)
 
 	trace_enum_init();
 
+#ifdef CONFIG_MODULES
+	register_module_notifier(&trace_module_nb);
+#endif
+
 #ifdef CONFIG_DYNAMIC_FTRACE
 	trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
 			&ftrace_update_tot_cnt, &tracing_dyn_info_fops);
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index fc58c50fbf01..a576bbe75577 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2034,7 +2034,7 @@ static int trace_module_notify(struct notifier_block *self,
 
 static struct notifier_block trace_module_nb = {
 	.notifier_call = trace_module_notify,
-	.priority = 0,
+	.priority = 1, /* higher than trace.c module notify */
 };
 #endif /* CONFIG_MODULES */
 
-- 
cgit v1.2.3


From 9828413d4715d4ed12bc92b161f4ed377d777ffb Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Date: Tue, 31 Mar 2015 17:23:45 -0400
Subject: tracing: Add enum_map file to show enums that have been mapped

Add a enum_map file in the tracing directory to see what enums have been
saved to convert in the print fmt files.

As this requires the enum mapping to be persistent in memory, it is only
created if the new config option CONFIG_TRACE_ENUM_MAP_FILE is enabled.
This is for debugging and will increase the persistent memory footprint
of the kernel.

Link: http://lkml.kernel.org/r/20150403013802.220157513@goodmis.org

Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/Kconfig |  28 ++++++
 kernel/trace/trace.c | 245 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 269 insertions(+), 4 deletions(-)

(limited to 'kernel')

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index a5da09c899dd..fedbdd7d5d1e 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -599,6 +599,34 @@ config RING_BUFFER_STARTUP_TEST
 
 	 If unsure, say N
 
+config TRACE_ENUM_MAP_FILE
+       bool "Show enum mappings for trace events"
+       depends on TRACING
+       help
+        The "print fmt" of the trace events will show the enum names instead
+	of their values. This can cause problems for user space tools that
+	use this string to parse the raw data as user space does not know
+	how to convert the string to its value.
+
+	To fix this, there's a special macro in the kernel that can be used
+	to convert the enum into its value. If this macro is used, then the
+	print fmt strings will have the enums converted to their values.
+
+	If something does not get converted properly, this option can be
+	used to show what enums the kernel tried to convert.
+
+	This option is for debugging the enum conversions. A file is created
+	in the tracing directory called "enum_map" that will show the enum
+	names matched with their values and what trace event system they
+	belong too.
+
+	Normally, the mapping of the strings to values will be freed after
+	boot up or module load. With this option, they will not be freed, as
+	they are needed for the "enum_map" file. Enabling this option will
+	increase the memory footprint of the running kernel.
+
+	If unsure, say N
+
 endif # FTRACE
 
 endif # TRACING_SUPPORT
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 28e6654e640d..39e69568302e 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -123,6 +123,42 @@ enum ftrace_dump_mode ftrace_dump_on_oops;
 /* When set, tracing will stop when a WARN*() is hit */
 int __disable_trace_on_warning;
 
+#ifdef CONFIG_TRACE_ENUM_MAP_FILE
+/* Map of enums to their values, for "enum_map" file */
+struct trace_enum_map_head {
+	struct module			*mod;
+	unsigned long			length;
+};
+
+union trace_enum_map_item;
+
+struct trace_enum_map_tail {
+	/*
+	 * "end" is first and points to NULL as it must be different
+	 * than "mod" or "enum_string"
+	 */
+	union trace_enum_map_item	*next;
+	const char			*end;	/* points to NULL */
+};
+
+static DEFINE_MUTEX(trace_enum_mutex);
+
+/*
+ * The trace_enum_maps are saved in an array with two extra elements,
+ * one at the beginning, and one at the end. The beginning item contains
+ * the count of the saved maps (head.length), and the module they
+ * belong to if not built in (head.mod). The ending item contains a
+ * pointer to the next array of saved enum_map items.
+ */
+union trace_enum_map_item {
+	struct trace_enum_map		map;
+	struct trace_enum_map_head	head;
+	struct trace_enum_map_tail	tail;
+};
+
+static union trace_enum_map_item *trace_enum_maps;
+#endif /* CONFIG_TRACE_ENUM_MAP_FILE */
+
 static int tracing_set_tracer(struct trace_array *tr, const char *buf);
 
 #define MAX_TRACER_SIZE		100
@@ -3908,7 +3944,169 @@ static const struct file_operations tracing_saved_cmdlines_size_fops = {
 	.write		= tracing_saved_cmdlines_size_write,
 };
 
-static void trace_insert_enum_map(struct trace_enum_map **start, int len)
+#ifdef CONFIG_TRACE_ENUM_MAP_FILE
+static union trace_enum_map_item *
+update_enum_map(union trace_enum_map_item *ptr)
+{
+	if (!ptr->map.enum_string) {
+		if (ptr->tail.next) {
+			ptr = ptr->tail.next;
+			/* Set ptr to the next real item (skip head) */
+			ptr++;
+		} else
+			return NULL;
+	}
+	return ptr;
+}
+
+static void *enum_map_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	union trace_enum_map_item *ptr = v;
+
+	/*
+	 * Paranoid! If ptr points to end, we don't want to increment past it.
+	 * This really should never happen.
+	 */
+	ptr = update_enum_map(ptr);
+	if (WARN_ON_ONCE(!ptr))
+		return NULL;
+
+	ptr++;
+
+	(*pos)++;
+
+	ptr = update_enum_map(ptr);
+
+	return ptr;
+}
+
+static void *enum_map_start(struct seq_file *m, loff_t *pos)
+{
+	union trace_enum_map_item *v;
+	loff_t l = 0;
+
+	mutex_lock(&trace_enum_mutex);
+
+	v = trace_enum_maps;
+	if (v)
+		v++;
+
+	while (v && l < *pos) {
+		v = enum_map_next(m, v, &l);
+	}
+
+	return v;
+}
+
+static void enum_map_stop(struct seq_file *m, void *v)
+{
+	mutex_unlock(&trace_enum_mutex);
+}
+
+static int enum_map_show(struct seq_file *m, void *v)
+{
+	union trace_enum_map_item *ptr = v;
+
+	seq_printf(m, "%s %ld (%s)\n",
+		   ptr->map.enum_string, ptr->map.enum_value,
+		   ptr->map.system);
+
+	return 0;
+}
+
+static const struct seq_operations tracing_enum_map_seq_ops = {
+	.start		= enum_map_start,
+	.next		= enum_map_next,
+	.stop		= enum_map_stop,
+	.show		= enum_map_show,
+};
+
+static int tracing_enum_map_open(struct inode *inode, struct file *filp)
+{
+	if (tracing_disabled)
+		return -ENODEV;
+
+	return seq_open(filp, &tracing_enum_map_seq_ops);
+}
+
+static const struct file_operations tracing_enum_map_fops = {
+	.open		= tracing_enum_map_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+static inline union trace_enum_map_item *
+trace_enum_jmp_to_tail(union trace_enum_map_item *ptr)
+{
+	/* Return tail of array given the head */
+	return ptr + ptr->head.length + 1;
+}
+
+static void
+trace_insert_enum_map_file(struct module *mod, struct trace_enum_map **start,
+			   int len)
+{
+	struct trace_enum_map **stop;
+	struct trace_enum_map **map;
+	union trace_enum_map_item *map_array;
+	union trace_enum_map_item *ptr;
+
+	stop = start + len;
+
+	/*
+	 * The trace_enum_maps contains the map plus a head and tail item,
+	 * where the head holds the module and length of array, and the
+	 * tail holds a pointer to the next list.
+	 */
+	map_array = kmalloc(sizeof(*map_array) * (len + 2), GFP_KERNEL);
+	if (!map_array) {
+		pr_warning("Unable to allocate trace enum mapping\n");
+		return;
+	}
+
+	mutex_lock(&trace_enum_mutex);
+
+	if (!trace_enum_maps)
+		trace_enum_maps = map_array;
+	else {
+		ptr = trace_enum_maps;
+		for (;;) {
+			ptr = trace_enum_jmp_to_tail(ptr);
+			if (!ptr->tail.next)
+				break;
+			ptr = ptr->tail.next;
+
+		}
+		ptr->tail.next = map_array;
+	}
+	map_array->head.mod = mod;
+	map_array->head.length = len;
+	map_array++;
+
+	for (map = start; (unsigned long)map < (unsigned long)stop; map++) {
+		map_array->map = **map;
+		map_array++;
+	}
+	memset(map_array, 0, sizeof(*map_array));
+
+	mutex_unlock(&trace_enum_mutex);
+}
+
+static void trace_create_enum_file(struct dentry *d_tracer)
+{
+	trace_create_file("enum_map", 0444, d_tracer,
+			  NULL, &tracing_enum_map_fops);
+}
+
+#else /* CONFIG_TRACE_ENUM_MAP_FILE */
+static inline void trace_create_enum_file(struct dentry *d_tracer) { }
+static inline void trace_insert_enum_map_file(struct module *mod,
+			      struct trace_enum_map **start, int len) { }
+#endif /* !CONFIG_TRACE_ENUM_MAP_FILE */
+
+static void trace_insert_enum_map(struct module *mod,
+				  struct trace_enum_map **start, int len)
 {
 	struct trace_enum_map **map;
 
@@ -3918,6 +4116,8 @@ static void trace_insert_enum_map(struct trace_enum_map **start, int len)
 	map = start;
 
 	trace_event_enum_update(map, len);
+
+	trace_insert_enum_map_file(mod, start, len);
 }
 
 static ssize_t
@@ -6562,7 +6762,7 @@ static void __init trace_enum_init(void)
 	int len;
 
 	len = __stop_ftrace_enum_maps - __start_ftrace_enum_maps;
-	trace_insert_enum_map(__start_ftrace_enum_maps, len);
+	trace_insert_enum_map(NULL, __start_ftrace_enum_maps, len);
 }
 
 #ifdef CONFIG_MODULES
@@ -6578,9 +6778,41 @@ static void trace_module_add_enums(struct module *mod)
 	if (trace_module_has_bad_taint(mod))
 		return;
 
-	trace_insert_enum_map(mod->trace_enums, mod->num_trace_enums);
+	trace_insert_enum_map(mod, mod->trace_enums, mod->num_trace_enums);
 }
 
+#ifdef CONFIG_TRACE_ENUM_MAP_FILE
+static void trace_module_remove_enums(struct module *mod)
+{
+	union trace_enum_map_item *map;
+	union trace_enum_map_item **last = &trace_enum_maps;
+
+	if (!mod->num_trace_enums)
+		return;
+
+	mutex_lock(&trace_enum_mutex);
+
+	map = trace_enum_maps;
+
+	while (map) {
+		if (map->head.mod == mod)
+			break;
+		map = trace_enum_jmp_to_tail(map);
+		last = &map->tail.next;
+		map = map->tail.next;
+	}
+	if (!map)
+		goto out;
+
+	*last = trace_enum_jmp_to_tail(map)->tail.next;
+	kfree(map);
+ out:
+	mutex_unlock(&trace_enum_mutex);
+}
+#else
+static inline void trace_module_remove_enums(struct module *mod) { }
+#endif /* CONFIG_TRACE_ENUM_MAP_FILE */
+
 static int trace_module_notify(struct notifier_block *self,
 			       unsigned long val, void *data)
 {
@@ -6590,6 +6822,9 @@ static int trace_module_notify(struct notifier_block *self,
 	case MODULE_STATE_COMING:
 		trace_module_add_enums(mod);
 		break;
+	case MODULE_STATE_GOING:
+		trace_module_remove_enums(mod);
+		break;
 	}
 
 	return 0;
@@ -6599,7 +6834,7 @@ static struct notifier_block trace_module_nb = {
 	.notifier_call = trace_module_notify,
 	.priority = 0,
 };
-#endif
+#endif /* CONFIG_MODULES */
 
 static __init int tracer_init_debugfs(void)
 {
@@ -6627,6 +6862,8 @@ static __init int tracer_init_debugfs(void)
 
 	trace_enum_init();
 
+	trace_create_enum_file(d_tracer);
+
 #ifdef CONFIG_MODULES
 	register_module_notifier(&trace_module_nb);
 #endif
-- 
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