From ee92fa443358f4fc0017c1d0d325c27b37802504 Mon Sep 17 00:00:00 2001
From: Chen Zhongjin <chenzhongjin@huawei.com>
Date: Thu, 9 Mar 2023 16:02:30 +0800
Subject: ftrace: Fix invalid address access in lookup_rec() when index is 0

KASAN reported follow problem:

 BUG: KASAN: use-after-free in lookup_rec
 Read of size 8 at addr ffff000199270ff0 by task modprobe
 CPU: 2 Comm: modprobe
 Call trace:
  kasan_report
  __asan_load8
  lookup_rec
  ftrace_location
  arch_check_ftrace_location
  check_kprobe_address_safe
  register_kprobe

When checking pg->records[pg->index - 1].ip in lookup_rec(), it can get a
pg which is newly added to ftrace_pages_start in ftrace_process_locs().
Before the first pg->index++, index is 0 and accessing pg->records[-1].ip
will cause this problem.

Don't check the ip when pg->index is 0.

Link: https://lore.kernel.org/linux-trace-kernel/20230309080230.36064-1-chenzhongjin@huawei.com

Cc: stable@vger.kernel.org
Fixes: 9644302e3315 ("ftrace: Speed up search by skipping pages by address")
Suggested-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'kernel/trace/ftrace.c')

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 750aa3f08b25..a47f7d93e32d 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1537,7 +1537,8 @@ static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
 	key.flags = end;	/* overload flags, as it is unsigned long */
 
 	for (pg = ftrace_pages_start; pg; pg = pg->next) {
-		if (end < pg->records[0].ip ||
+		if (pg->index == 0 ||
+		    end < pg->records[0].ip ||
 		    start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
 			continue;
 		rec = bsearch(&key, pg->records, pg->index,
-- 
cgit 


From 8732565549011cabbea08329a1aefd78a68d96c7 Mon Sep 17 00:00:00 2001
From: Tom Rix <trix@redhat.com>
Date: Sat, 11 Mar 2023 08:51:13 -0500
Subject: ftrace: Set direct_ops storage-class-specifier to static

smatch reports this warning
kernel/trace/ftrace.c:2594:19: warning:
  symbol 'direct_ops' was not declared. Should it be static?

The variable direct_ops is only used in ftrace.c, so it should be static

Link: https://lore.kernel.org/linux-trace-kernel/20230311135113.711824-1-trix@redhat.com

Signed-off-by: Tom Rix <trix@redhat.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'kernel/trace/ftrace.c')

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index a47f7d93e32d..ec2897a76004 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2503,7 +2503,7 @@ static void call_direct_funcs(unsigned long ip, unsigned long pip,
 	arch_ftrace_set_direct_caller(fregs, addr);
 }
 
-struct ftrace_ops direct_ops = {
+static struct ftrace_ops direct_ops = {
 	.func		= call_direct_funcs,
 	.flags		= FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
 			  | FTRACE_OPS_FL_PERMANENT,
-- 
cgit 


From 3703bd54cd37e7875f51ece8df8c85c184e40bba Mon Sep 17 00:00:00 2001
From: Zhen Lei <thunder.leizhen@huawei.com>
Date: Wed, 8 Mar 2023 15:38:46 +0800
Subject: kallsyms: Delete an unused parameter related to
 {module_}kallsyms_on_each_symbol()

The parameter 'struct module *' in the hook function associated with
{module_}kallsyms_on_each_symbol() is no longer used. Delete it.

Suggested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 include/linux/kallsyms.h   | 7 +++----
 include/linux/module.h     | 6 ++----
 kernel/kallsyms.c          | 5 ++---
 kernel/kallsyms_selftest.c | 6 +++---
 kernel/livepatch/core.c    | 3 +--
 kernel/module/kallsyms.c   | 5 ++---
 kernel/trace/ftrace.c      | 3 +--
 7 files changed, 14 insertions(+), 21 deletions(-)

(limited to 'kernel/trace/ftrace.c')

diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
index 0065209cc004..fe3c9993b5bf 100644
--- a/include/linux/kallsyms.h
+++ b/include/linux/kallsyms.h
@@ -67,8 +67,7 @@ static inline void *dereference_symbol_descriptor(void *ptr)
 
 #ifdef CONFIG_KALLSYMS
 unsigned long kallsyms_sym_address(int idx);
-int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
-				      unsigned long),
+int kallsyms_on_each_symbol(int (*fn)(void *, const char *, unsigned long),
 			    void *data);
 int kallsyms_on_each_match_symbol(int (*fn)(void *, unsigned long),
 				  const char *name, void *data);
@@ -166,8 +165,8 @@ static inline bool kallsyms_show_value(const struct cred *cred)
 	return false;
 }
 
-static inline int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
-					  unsigned long), void *data)
+static inline int kallsyms_on_each_symbol(int (*fn)(void *, const char *, unsigned long),
+					  void *data)
 {
 	return -EOPNOTSUPP;
 }
diff --git a/include/linux/module.h b/include/linux/module.h
index c3b357196470..d2d900077bde 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -965,13 +965,11 @@ static inline bool module_sig_ok(struct module *module)
 
 #if defined(CONFIG_MODULES) && defined(CONFIG_KALLSYMS)
 int module_kallsyms_on_each_symbol(const char *modname,
-				   int (*fn)(void *, const char *,
-					     struct module *, unsigned long),
+				   int (*fn)(void *, const char *, unsigned long),
 				   void *data);
 #else
 static inline int module_kallsyms_on_each_symbol(const char *modname,
-						 int (*fn)(void *, const char *,
-						 struct module *, unsigned long),
+						 int (*fn)(void *, const char *, unsigned long),
 						 void *data)
 {
 	return -EOPNOTSUPP;
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index 83f499182c9a..77747391f49b 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -288,8 +288,7 @@ unsigned long kallsyms_lookup_name(const char *name)
  * Iterate over all symbols in vmlinux.  For symbols from modules use
  * module_kallsyms_on_each_symbol instead.
  */
-int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
-				      unsigned long),
+int kallsyms_on_each_symbol(int (*fn)(void *, const char *, unsigned long),
 			    void *data)
 {
 	char namebuf[KSYM_NAME_LEN];
@@ -299,7 +298,7 @@ int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
 
 	for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
 		off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
-		ret = fn(data, namebuf, NULL, kallsyms_sym_address(i));
+		ret = fn(data, namebuf, kallsyms_sym_address(i));
 		if (ret != 0)
 			return ret;
 		cond_resched();
diff --git a/kernel/kallsyms_selftest.c b/kernel/kallsyms_selftest.c
index bfbc12da3326..a2e3745d15c4 100644
--- a/kernel/kallsyms_selftest.c
+++ b/kernel/kallsyms_selftest.c
@@ -95,7 +95,7 @@ static struct test_item test_items[] = {
 
 static char stub_name[KSYM_NAME_LEN];
 
-static int stat_symbol_len(void *data, const char *name, struct module *mod, unsigned long addr)
+static int stat_symbol_len(void *data, const char *name, unsigned long addr)
 {
 	*(u32 *)data += strlen(name);
 
@@ -154,7 +154,7 @@ static void test_kallsyms_compression_ratio(void)
 	pr_info(" ---------------------------------------------------------\n");
 }
 
-static int lookup_name(void *data, const char *name, struct module *mod, unsigned long addr)
+static int lookup_name(void *data, const char *name, unsigned long addr)
 {
 	u64 t0, t1, t;
 	struct test_stat *stat = (struct test_stat *)data;
@@ -207,7 +207,7 @@ static bool match_cleanup_name(const char *s, const char *name)
 	return !strncmp(s, name, len);
 }
 
-static int find_symbol(void *data, const char *name, struct module *mod, unsigned long addr)
+static int find_symbol(void *data, const char *name, unsigned long addr)
 {
 	struct test_stat *stat = (struct test_stat *)data;
 
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 4bd2d5e10f20..1de2c40cc378 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -142,8 +142,7 @@ static int klp_match_callback(void *data, unsigned long addr)
 	return 0;
 }
 
-static int klp_find_callback(void *data, const char *name,
-			     struct module *mod, unsigned long addr)
+static int klp_find_callback(void *data, const char *name, unsigned long addr)
 {
 	struct klp_find_arg *args = data;
 
diff --git a/kernel/module/kallsyms.c b/kernel/module/kallsyms.c
index 8e89f459ffdd..3320586584f1 100644
--- a/kernel/module/kallsyms.c
+++ b/kernel/module/kallsyms.c
@@ -503,8 +503,7 @@ unsigned long module_kallsyms_lookup_name(const char *name)
 }
 
 int module_kallsyms_on_each_symbol(const char *modname,
-				   int (*fn)(void *, const char *,
-					     struct module *, unsigned long),
+				   int (*fn)(void *, const char *, unsigned long),
 				   void *data)
 {
 	struct module *mod;
@@ -533,7 +532,7 @@ int module_kallsyms_on_each_symbol(const char *modname,
 				continue;
 
 			ret = fn(data, kallsyms_symbol_name(kallsyms, i),
-				 mod, kallsyms_symbol_value(sym));
+				 kallsyms_symbol_value(sym));
 			if (ret != 0)
 				goto out;
 		}
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 29baa97d0d53..76caca8f496a 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -8391,8 +8391,7 @@ struct kallsyms_data {
  * and returns 1 in case we resolved all the requested symbols,
  * 0 otherwise.
  */
-static int kallsyms_callback(void *data, const char *name,
-			     struct module *mod, unsigned long addr)
+static int kallsyms_callback(void *data, const char *name, unsigned long addr)
 {
 	struct kallsyms_data *args = data;
 	const char **sym;
-- 
cgit 


From 59495740f79524bebe4ecb8097cf206f86587b25 Mon Sep 17 00:00:00 2001
From: Florent Revest <revest@chromium.org>
Date: Tue, 21 Mar 2023 15:04:18 +0100
Subject: ftrace: Let unregister_ftrace_direct_multi() call
 ftrace_free_filter()

A common pattern when using the ftrace_direct_multi API is to unregister
the ops and also immediately free its filter. We've noticed it's very
easy for users to miss calling ftrace_free_filter().

This adds a "free_filters" argument to unregister_ftrace_direct_multi()
to both remind the user they should free filters and also to make their
life easier.

Link: https://lkml.kernel.org/r/20230321140424.345218-2-revest@chromium.org

Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Florent Revest <revest@chromium.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 include/linux/ftrace.h                      | 6 ++++--
 kernel/bpf/trampoline.c                     | 2 +-
 kernel/trace/ftrace.c                       | 6 +++++-
 samples/ftrace/ftrace-direct-multi-modify.c | 3 +--
 samples/ftrace/ftrace-direct-multi.c        | 3 +--
 5 files changed, 12 insertions(+), 8 deletions(-)

(limited to 'kernel/trace/ftrace.c')

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 366c730beaa3..5b68ee874bc1 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -407,7 +407,8 @@ int ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
 				unsigned long new_addr);
 unsigned long ftrace_find_rec_direct(unsigned long ip);
 int register_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr);
-int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr);
+int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr,
+				   bool free_filters);
 int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr);
 int modify_ftrace_direct_multi_nolock(struct ftrace_ops *ops, unsigned long addr);
 
@@ -446,7 +447,8 @@ static inline int register_ftrace_direct_multi(struct ftrace_ops *ops, unsigned
 {
 	return -ENODEV;
 }
-static inline int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
+static inline int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr,
+						 bool free_filters)
 {
 	return -ENODEV;
 }
diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index d0ed7d6f5eec..88bc23f1e10a 100644
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -198,7 +198,7 @@ static int unregister_fentry(struct bpf_trampoline *tr, void *old_addr)
 	int ret;
 
 	if (tr->func.ftrace_managed)
-		ret = unregister_ftrace_direct_multi(tr->fops, (long)old_addr);
+		ret = unregister_ftrace_direct_multi(tr->fops, (long)old_addr, false);
 	else
 		ret = bpf_arch_text_poke(ip, BPF_MOD_CALL, old_addr, NULL);
 
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 0feea145bb29..98434196c6a1 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5805,7 +5805,8 @@ EXPORT_SYMBOL_GPL(register_ftrace_direct_multi);
  *  0 on success
  *  -EINVAL - The @ops object was not properly registered.
  */
-int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
+int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr,
+				   bool free_filters)
 {
 	struct ftrace_hash *hash = ops->func_hash->filter_hash;
 	int err;
@@ -5823,6 +5824,9 @@ int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
 	/* cleanup for possible another register call */
 	ops->func = NULL;
 	ops->trampoline = 0;
+
+	if (free_filters)
+		ftrace_free_filter(ops);
 	return err;
 }
 EXPORT_SYMBOL_GPL(unregister_ftrace_direct_multi);
diff --git a/samples/ftrace/ftrace-direct-multi-modify.c b/samples/ftrace/ftrace-direct-multi-modify.c
index b58c594efb51..196b43971cb5 100644
--- a/samples/ftrace/ftrace-direct-multi-modify.c
+++ b/samples/ftrace/ftrace-direct-multi-modify.c
@@ -151,8 +151,7 @@ static int __init ftrace_direct_multi_init(void)
 static void __exit ftrace_direct_multi_exit(void)
 {
 	kthread_stop(simple_tsk);
-	unregister_ftrace_direct_multi(&direct, my_tramp);
-	ftrace_free_filter(&direct);
+	unregister_ftrace_direct_multi(&direct, my_tramp, true);
 }
 
 module_init(ftrace_direct_multi_init);
diff --git a/samples/ftrace/ftrace-direct-multi.c b/samples/ftrace/ftrace-direct-multi.c
index c27cf130c319..ea0e88ee5e43 100644
--- a/samples/ftrace/ftrace-direct-multi.c
+++ b/samples/ftrace/ftrace-direct-multi.c
@@ -78,8 +78,7 @@ static int __init ftrace_direct_multi_init(void)
 
 static void __exit ftrace_direct_multi_exit(void)
 {
-	unregister_ftrace_direct_multi(&direct, (unsigned long) my_tramp);
-	ftrace_free_filter(&direct);
+	unregister_ftrace_direct_multi(&direct, (unsigned long) my_tramp, true);
 }
 
 module_init(ftrace_direct_multi_init);
-- 
cgit 


From 8788ca164eb4bad9a2a82c7778223c15ef800b8b Mon Sep 17 00:00:00 2001
From: Florent Revest <revest@chromium.org>
Date: Tue, 21 Mar 2023 15:04:20 +0100
Subject: ftrace: Remove the legacy _ftrace_direct API

This API relies on a single global ops, used for all direct calls
registered with it. However, to implement arm64 direct calls, we need
each ops to point to a single direct call trampoline.

Link: https://lkml.kernel.org/r/20230321140424.345218-4-revest@chromium.org

Signed-off-by: Florent Revest <revest@chromium.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 include/linux/ftrace.h |  32 ----
 kernel/trace/ftrace.c  | 393 -------------------------------------------------
 2 files changed, 425 deletions(-)

(limited to 'kernel/trace/ftrace.c')

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 5b68ee874bc1..2f400c9f0787 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -397,14 +397,6 @@ struct ftrace_func_entry {
 
 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 extern int ftrace_direct_func_count;
-int register_ftrace_direct(unsigned long ip, unsigned long addr);
-int unregister_ftrace_direct(unsigned long ip, unsigned long addr);
-int modify_ftrace_direct(unsigned long ip, unsigned long old_addr, unsigned long new_addr);
-struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr);
-int ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
-				struct dyn_ftrace *rec,
-				unsigned long old_addr,
-				unsigned long new_addr);
 unsigned long ftrace_find_rec_direct(unsigned long ip);
 int register_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr);
 int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr,
@@ -415,30 +407,6 @@ int modify_ftrace_direct_multi_nolock(struct ftrace_ops *ops, unsigned long addr
 #else
 struct ftrace_ops;
 # define ftrace_direct_func_count 0
-static inline int register_ftrace_direct(unsigned long ip, unsigned long addr)
-{
-	return -ENOTSUPP;
-}
-static inline int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
-{
-	return -ENOTSUPP;
-}
-static inline int modify_ftrace_direct(unsigned long ip,
-				       unsigned long old_addr, unsigned long new_addr)
-{
-	return -ENOTSUPP;
-}
-static inline struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)
-{
-	return NULL;
-}
-static inline int ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
-					      struct dyn_ftrace *rec,
-					      unsigned long old_addr,
-					      unsigned long new_addr)
-{
-	return -ENODEV;
-}
 static inline unsigned long ftrace_find_rec_direct(unsigned long ip)
 {
 	return 0;
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 98434196c6a1..fbc9abfa1a3e 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2591,20 +2591,6 @@ static void call_direct_funcs(unsigned long ip, unsigned long pip,
 
 	arch_ftrace_set_direct_caller(fregs, addr);
 }
-
-static struct ftrace_ops direct_ops = {
-	.func		= call_direct_funcs,
-	.flags		= FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
-			  | FTRACE_OPS_FL_PERMANENT,
-	/*
-	 * By declaring the main trampoline as this trampoline
-	 * it will never have one allocated for it. Allocated
-	 * trampolines should not call direct functions.
-	 * The direct_ops should only be called by the builtin
-	 * ftrace_regs_caller trampoline.
-	 */
-	.trampoline	= FTRACE_REGS_ADDR,
-};
 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
 
 /**
@@ -5301,387 +5287,8 @@ struct ftrace_direct_func {
 
 static LIST_HEAD(ftrace_direct_funcs);
 
-/**
- * ftrace_find_direct_func - test an address if it is a registered direct caller
- * @addr: The address of a registered direct caller
- *
- * This searches to see if a ftrace direct caller has been registered
- * at a specific address, and if so, it returns a descriptor for it.
- *
- * This can be used by architecture code to see if an address is
- * a direct caller (trampoline) attached to a fentry/mcount location.
- * This is useful for the function_graph tracer, as it may need to
- * do adjustments if it traced a location that also has a direct
- * trampoline attached to it.
- */
-struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)
-{
-	struct ftrace_direct_func *entry;
-	bool found = false;
-
-	/* May be called by fgraph trampoline (protected by rcu tasks) */
-	list_for_each_entry_rcu(entry, &ftrace_direct_funcs, next) {
-		if (entry->addr == addr) {
-			found = true;
-			break;
-		}
-	}
-	if (found)
-		return entry;
-
-	return NULL;
-}
-
-static struct ftrace_direct_func *ftrace_alloc_direct_func(unsigned long addr)
-{
-	struct ftrace_direct_func *direct;
-
-	direct = kmalloc(sizeof(*direct), GFP_KERNEL);
-	if (!direct)
-		return NULL;
-	direct->addr = addr;
-	direct->count = 0;
-	list_add_rcu(&direct->next, &ftrace_direct_funcs);
-	ftrace_direct_func_count++;
-	return direct;
-}
-
 static int register_ftrace_function_nolock(struct ftrace_ops *ops);
 
-/**
- * register_ftrace_direct - Call a custom trampoline directly
- * @ip: The address of the nop at the beginning of a function
- * @addr: The address of the trampoline to call at @ip
- *
- * This is used to connect a direct call from the nop location (@ip)
- * at the start of ftrace traced functions. The location that it calls
- * (@addr) must be able to handle a direct call, and save the parameters
- * of the function being traced, and restore them (or inject new ones
- * if needed), before returning.
- *
- * Returns:
- *  0 on success
- *  -EBUSY - Another direct function is already attached (there can be only one)
- *  -ENODEV - @ip does not point to a ftrace nop location (or not supported)
- *  -ENOMEM - There was an allocation failure.
- */
-int register_ftrace_direct(unsigned long ip, unsigned long addr)
-{
-	struct ftrace_direct_func *direct;
-	struct ftrace_func_entry *entry;
-	struct ftrace_hash *free_hash = NULL;
-	struct dyn_ftrace *rec;
-	int ret = -ENODEV;
-
-	mutex_lock(&direct_mutex);
-
-	ip = ftrace_location(ip);
-	if (!ip)
-		goto out_unlock;
-
-	/* See if there's a direct function at @ip already */
-	ret = -EBUSY;
-	if (ftrace_find_rec_direct(ip))
-		goto out_unlock;
-
-	ret = -ENODEV;
-	rec = lookup_rec(ip, ip);
-	if (!rec)
-		goto out_unlock;
-
-	/*
-	 * Check if the rec says it has a direct call but we didn't
-	 * find one earlier?
-	 */
-	if (WARN_ON(rec->flags & FTRACE_FL_DIRECT))
-		goto out_unlock;
-
-	/* Make sure the ip points to the exact record */
-	if (ip != rec->ip) {
-		ip = rec->ip;
-		/* Need to check this ip for a direct. */
-		if (ftrace_find_rec_direct(ip))
-			goto out_unlock;
-	}
-
-	ret = -ENOMEM;
-	direct = ftrace_find_direct_func(addr);
-	if (!direct) {
-		direct = ftrace_alloc_direct_func(addr);
-		if (!direct)
-			goto out_unlock;
-	}
-
-	entry = ftrace_add_rec_direct(ip, addr, &free_hash);
-	if (!entry)
-		goto out_unlock;
-
-	ret = ftrace_set_filter_ip(&direct_ops, ip, 0, 0);
-
-	if (!ret && !(direct_ops.flags & FTRACE_OPS_FL_ENABLED)) {
-		ret = register_ftrace_function_nolock(&direct_ops);
-		if (ret)
-			ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
-	}
-
-	if (ret) {
-		remove_hash_entry(direct_functions, entry);
-		kfree(entry);
-		if (!direct->count) {
-			list_del_rcu(&direct->next);
-			synchronize_rcu_tasks();
-			kfree(direct);
-			if (free_hash)
-				free_ftrace_hash(free_hash);
-			free_hash = NULL;
-			ftrace_direct_func_count--;
-		}
-	} else {
-		direct->count++;
-	}
- out_unlock:
-	mutex_unlock(&direct_mutex);
-
-	if (free_hash) {
-		synchronize_rcu_tasks();
-		free_ftrace_hash(free_hash);
-	}
-
-	return ret;
-}
-EXPORT_SYMBOL_GPL(register_ftrace_direct);
-
-static struct ftrace_func_entry *find_direct_entry(unsigned long *ip,
-						   struct dyn_ftrace **recp)
-{
-	struct ftrace_func_entry *entry;
-	struct dyn_ftrace *rec;
-
-	rec = lookup_rec(*ip, *ip);
-	if (!rec)
-		return NULL;
-
-	entry = __ftrace_lookup_ip(direct_functions, rec->ip);
-	if (!entry) {
-		WARN_ON(rec->flags & FTRACE_FL_DIRECT);
-		return NULL;
-	}
-
-	WARN_ON(!(rec->flags & FTRACE_FL_DIRECT));
-
-	/* Passed in ip just needs to be on the call site */
-	*ip = rec->ip;
-
-	if (recp)
-		*recp = rec;
-
-	return entry;
-}
-
-int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
-{
-	struct ftrace_direct_func *direct;
-	struct ftrace_func_entry *entry;
-	struct ftrace_hash *hash;
-	int ret = -ENODEV;
-
-	mutex_lock(&direct_mutex);
-
-	ip = ftrace_location(ip);
-	if (!ip)
-		goto out_unlock;
-
-	entry = find_direct_entry(&ip, NULL);
-	if (!entry)
-		goto out_unlock;
-
-	hash = direct_ops.func_hash->filter_hash;
-	if (hash->count == 1)
-		unregister_ftrace_function(&direct_ops);
-
-	ret = ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
-
-	WARN_ON(ret);
-
-	remove_hash_entry(direct_functions, entry);
-
-	direct = ftrace_find_direct_func(addr);
-	if (!WARN_ON(!direct)) {
-		/* This is the good path (see the ! before WARN) */
-		direct->count--;
-		WARN_ON(direct->count < 0);
-		if (!direct->count) {
-			list_del_rcu(&direct->next);
-			synchronize_rcu_tasks();
-			kfree(direct);
-			kfree(entry);
-			ftrace_direct_func_count--;
-		}
-	}
- out_unlock:
-	mutex_unlock(&direct_mutex);
-
-	return ret;
-}
-EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
-
-static struct ftrace_ops stub_ops = {
-	.func		= ftrace_stub,
-};
-
-/**
- * ftrace_modify_direct_caller - modify ftrace nop directly
- * @entry: The ftrace hash entry of the direct helper for @rec
- * @rec: The record representing the function site to patch
- * @old_addr: The location that the site at @rec->ip currently calls
- * @new_addr: The location that the site at @rec->ip should call
- *
- * An architecture may overwrite this function to optimize the
- * changing of the direct callback on an ftrace nop location.
- * This is called with the ftrace_lock mutex held, and no other
- * ftrace callbacks are on the associated record (@rec). Thus,
- * it is safe to modify the ftrace record, where it should be
- * currently calling @old_addr directly, to call @new_addr.
- *
- * This is called with direct_mutex locked.
- *
- * Safety checks should be made to make sure that the code at
- * @rec->ip is currently calling @old_addr. And this must
- * also update entry->direct to @new_addr.
- */
-int __weak ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
-				       struct dyn_ftrace *rec,
-				       unsigned long old_addr,
-				       unsigned long new_addr)
-{
-	unsigned long ip = rec->ip;
-	int ret;
-
-	lockdep_assert_held(&direct_mutex);
-
-	/*
-	 * The ftrace_lock was used to determine if the record
-	 * had more than one registered user to it. If it did,
-	 * we needed to prevent that from changing to do the quick
-	 * switch. But if it did not (only a direct caller was attached)
-	 * then this function is called. But this function can deal
-	 * with attached callers to the rec that we care about, and
-	 * since this function uses standard ftrace calls that take
-	 * the ftrace_lock mutex, we need to release it.
-	 */
-	mutex_unlock(&ftrace_lock);
-
-	/*
-	 * By setting a stub function at the same address, we force
-	 * the code to call the iterator and the direct_ops helper.
-	 * This means that @ip does not call the direct call, and
-	 * we can simply modify it.
-	 */
-	ret = ftrace_set_filter_ip(&stub_ops, ip, 0, 0);
-	if (ret)
-		goto out_lock;
-
-	ret = register_ftrace_function_nolock(&stub_ops);
-	if (ret) {
-		ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
-		goto out_lock;
-	}
-
-	entry->direct = new_addr;
-
-	/*
-	 * By removing the stub, we put back the direct call, calling
-	 * the @new_addr.
-	 */
-	unregister_ftrace_function(&stub_ops);
-	ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
-
- out_lock:
-	mutex_lock(&ftrace_lock);
-
-	return ret;
-}
-
-/**
- * modify_ftrace_direct - Modify an existing direct call to call something else
- * @ip: The instruction pointer to modify
- * @old_addr: The address that the current @ip calls directly
- * @new_addr: The address that the @ip should call
- *
- * This modifies a ftrace direct caller at an instruction pointer without
- * having to disable it first. The direct call will switch over to the
- * @new_addr without missing anything.
- *
- * Returns: zero on success. Non zero on error, which includes:
- *  -ENODEV : the @ip given has no direct caller attached
- *  -EINVAL : the @old_addr does not match the current direct caller
- */
-int modify_ftrace_direct(unsigned long ip,
-			 unsigned long old_addr, unsigned long new_addr)
-{
-	struct ftrace_direct_func *direct, *new_direct = NULL;
-	struct ftrace_func_entry *entry;
-	struct dyn_ftrace *rec;
-	int ret = -ENODEV;
-
-	mutex_lock(&direct_mutex);
-
-	mutex_lock(&ftrace_lock);
-
-	ip = ftrace_location(ip);
-	if (!ip)
-		goto out_unlock;
-
-	entry = find_direct_entry(&ip, &rec);
-	if (!entry)
-		goto out_unlock;
-
-	ret = -EINVAL;
-	if (entry->direct != old_addr)
-		goto out_unlock;
-
-	direct = ftrace_find_direct_func(old_addr);
-	if (WARN_ON(!direct))
-		goto out_unlock;
-	if (direct->count > 1) {
-		ret = -ENOMEM;
-		new_direct = ftrace_alloc_direct_func(new_addr);
-		if (!new_direct)
-			goto out_unlock;
-		direct->count--;
-		new_direct->count++;
-	} else {
-		direct->addr = new_addr;
-	}
-
-	/*
-	 * If there's no other ftrace callback on the rec->ip location,
-	 * then it can be changed directly by the architecture.
-	 * If there is another caller, then we just need to change the
-	 * direct caller helper to point to @new_addr.
-	 */
-	if (ftrace_rec_count(rec) == 1) {
-		ret = ftrace_modify_direct_caller(entry, rec, old_addr, new_addr);
-	} else {
-		entry->direct = new_addr;
-		ret = 0;
-	}
-
-	if (unlikely(ret && new_direct)) {
-		direct->count++;
-		list_del_rcu(&new_direct->next);
-		synchronize_rcu_tasks();
-		kfree(new_direct);
-		ftrace_direct_func_count--;
-	}
-
- out_unlock:
-	mutex_unlock(&ftrace_lock);
-	mutex_unlock(&direct_mutex);
-	return ret;
-}
-EXPORT_SYMBOL_GPL(modify_ftrace_direct);
-
 #define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS)
 
 static int check_direct_multi(struct ftrace_ops *ops)
-- 
cgit 


From da8bdfbd422333fbb7c85ac1d7f18592d17d6665 Mon Sep 17 00:00:00 2001
From: Florent Revest <revest@chromium.org>
Date: Tue, 21 Mar 2023 15:04:21 +0100
Subject: ftrace: Rename _ftrace_direct_multi APIs to _ftrace_direct APIs

Now that the original _ftrace_direct APIs are gone, the "_multi"
suffixes only add confusion.

Link: https://lkml.kernel.org/r/20230321140424.345218-5-revest@chromium.org

Signed-off-by: Florent Revest <revest@chromium.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 include/linux/ftrace.h                      | 20 ++++++++---------
 kernel/bpf/trampoline.c                     | 12 +++++-----
 kernel/trace/ftrace.c                       | 34 ++++++++++++++---------------
 kernel/trace/trace_selftest.c               |  9 ++++----
 samples/Kconfig                             |  2 +-
 samples/ftrace/ftrace-direct-modify.c       |  8 +++----
 samples/ftrace/ftrace-direct-multi-modify.c |  8 +++----
 samples/ftrace/ftrace-direct-multi.c        |  4 ++--
 samples/ftrace/ftrace-direct-too.c          |  6 ++---
 samples/ftrace/ftrace-direct.c              |  6 ++---
 10 files changed, 55 insertions(+), 54 deletions(-)

(limited to 'kernel/trace/ftrace.c')

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 2f400c9f0787..abee60865fc7 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -398,11 +398,11 @@ struct ftrace_func_entry {
 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 extern int ftrace_direct_func_count;
 unsigned long ftrace_find_rec_direct(unsigned long ip);
-int register_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr);
-int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr,
-				   bool free_filters);
-int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr);
-int modify_ftrace_direct_multi_nolock(struct ftrace_ops *ops, unsigned long addr);
+int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr);
+int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr,
+			     bool free_filters);
+int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr);
+int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr);
 
 #else
 struct ftrace_ops;
@@ -411,20 +411,20 @@ static inline unsigned long ftrace_find_rec_direct(unsigned long ip)
 {
 	return 0;
 }
-static inline int register_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
+static inline int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
 {
 	return -ENODEV;
 }
-static inline int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr,
-						 bool free_filters)
+static inline int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr,
+					   bool free_filters)
 {
 	return -ENODEV;
 }
-static inline int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
+static inline int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
 {
 	return -ENODEV;
 }
-static inline int modify_ftrace_direct_multi_nolock(struct ftrace_ops *ops, unsigned long addr)
+static inline int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr)
 {
 	return -ENODEV;
 }
diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index 88bc23f1e10a..a14d0af534b3 100644
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -45,8 +45,8 @@ static int bpf_tramp_ftrace_ops_func(struct ftrace_ops *ops, enum ftrace_ops_cmd
 		lockdep_assert_held_once(&tr->mutex);
 
 		/* Instead of updating the trampoline here, we propagate
-		 * -EAGAIN to register_ftrace_direct_multi(). Then we can
-		 * retry register_ftrace_direct_multi() after updating the
+		 * -EAGAIN to register_ftrace_direct(). Then we can
+		 * retry register_ftrace_direct() after updating the
 		 * trampoline.
 		 */
 		if ((tr->flags & BPF_TRAMP_F_CALL_ORIG) &&
@@ -198,7 +198,7 @@ static int unregister_fentry(struct bpf_trampoline *tr, void *old_addr)
 	int ret;
 
 	if (tr->func.ftrace_managed)
-		ret = unregister_ftrace_direct_multi(tr->fops, (long)old_addr, false);
+		ret = unregister_ftrace_direct(tr->fops, (long)old_addr, false);
 	else
 		ret = bpf_arch_text_poke(ip, BPF_MOD_CALL, old_addr, NULL);
 
@@ -215,9 +215,9 @@ static int modify_fentry(struct bpf_trampoline *tr, void *old_addr, void *new_ad
 
 	if (tr->func.ftrace_managed) {
 		if (lock_direct_mutex)
-			ret = modify_ftrace_direct_multi(tr->fops, (long)new_addr);
+			ret = modify_ftrace_direct(tr->fops, (long)new_addr);
 		else
-			ret = modify_ftrace_direct_multi_nolock(tr->fops, (long)new_addr);
+			ret = modify_ftrace_direct_nolock(tr->fops, (long)new_addr);
 	} else {
 		ret = bpf_arch_text_poke(ip, BPF_MOD_CALL, old_addr, new_addr);
 	}
@@ -243,7 +243,7 @@ static int register_fentry(struct bpf_trampoline *tr, void *new_addr)
 
 	if (tr->func.ftrace_managed) {
 		ftrace_set_filter_ip(tr->fops, (unsigned long)ip, 0, 1);
-		ret = register_ftrace_direct_multi(tr->fops, (long)new_addr);
+		ret = register_ftrace_direct(tr->fops, (long)new_addr);
 	} else {
 		ret = bpf_arch_text_poke(ip, BPF_MOD_CALL, NULL, new_addr);
 	}
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index fbc9abfa1a3e..845c4012630f 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5318,7 +5318,7 @@ static void remove_direct_functions_hash(struct ftrace_hash *hash, unsigned long
 }
 
 /**
- * register_ftrace_direct_multi - Call a custom trampoline directly
+ * register_ftrace_direct - Call a custom trampoline directly
  * for multiple functions registered in @ops
  * @ops: The address of the struct ftrace_ops object
  * @addr: The address of the trampoline to call at @ops functions
@@ -5339,7 +5339,7 @@ static void remove_direct_functions_hash(struct ftrace_hash *hash, unsigned long
  *  -ENODEV  - @ip does not point to a ftrace nop location (or not supported)
  *  -ENOMEM  - There was an allocation failure.
  */
-int register_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
+int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
 {
 	struct ftrace_hash *hash, *free_hash = NULL;
 	struct ftrace_func_entry *entry, *new;
@@ -5397,11 +5397,11 @@ int register_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
 	}
 	return err;
 }
-EXPORT_SYMBOL_GPL(register_ftrace_direct_multi);
+EXPORT_SYMBOL_GPL(register_ftrace_direct);
 
 /**
- * unregister_ftrace_direct_multi - Remove calls to custom trampoline
- * previously registered by register_ftrace_direct_multi for @ops object.
+ * unregister_ftrace_direct - Remove calls to custom trampoline
+ * previously registered by register_ftrace_direct for @ops object.
  * @ops: The address of the struct ftrace_ops object
  *
  * This is used to remove a direct calls to @addr from the nop locations
@@ -5412,8 +5412,8 @@ EXPORT_SYMBOL_GPL(register_ftrace_direct_multi);
  *  0 on success
  *  -EINVAL - The @ops object was not properly registered.
  */
-int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr,
-				   bool free_filters)
+int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr,
+			     bool free_filters)
 {
 	struct ftrace_hash *hash = ops->func_hash->filter_hash;
 	int err;
@@ -5436,10 +5436,10 @@ int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr,
 		ftrace_free_filter(ops);
 	return err;
 }
-EXPORT_SYMBOL_GPL(unregister_ftrace_direct_multi);
+EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
 
 static int
-__modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
+__modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
 {
 	struct ftrace_hash *hash;
 	struct ftrace_func_entry *entry, *iter;
@@ -5486,7 +5486,7 @@ __modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
 }
 
 /**
- * modify_ftrace_direct_multi_nolock - Modify an existing direct 'multi' call
+ * modify_ftrace_direct_nolock - Modify an existing direct 'multi' call
  * to call something else
  * @ops: The address of the struct ftrace_ops object
  * @addr: The address of the new trampoline to call at @ops functions
@@ -5503,19 +5503,19 @@ __modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
  * Returns: zero on success. Non zero on error, which includes:
  *  -EINVAL - The @ops object was not properly registered.
  */
-int modify_ftrace_direct_multi_nolock(struct ftrace_ops *ops, unsigned long addr)
+int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr)
 {
 	if (check_direct_multi(ops))
 		return -EINVAL;
 	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
 		return -EINVAL;
 
-	return __modify_ftrace_direct_multi(ops, addr);
+	return __modify_ftrace_direct(ops, addr);
 }
-EXPORT_SYMBOL_GPL(modify_ftrace_direct_multi_nolock);
+EXPORT_SYMBOL_GPL(modify_ftrace_direct_nolock);
 
 /**
- * modify_ftrace_direct_multi - Modify an existing direct 'multi' call
+ * modify_ftrace_direct - Modify an existing direct 'multi' call
  * to call something else
  * @ops: The address of the struct ftrace_ops object
  * @addr: The address of the new trampoline to call at @ops functions
@@ -5529,7 +5529,7 @@ EXPORT_SYMBOL_GPL(modify_ftrace_direct_multi_nolock);
  * Returns: zero on success. Non zero on error, which includes:
  *  -EINVAL - The @ops object was not properly registered.
  */
-int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
+int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
 {
 	int err;
 
@@ -5539,11 +5539,11 @@ int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
 		return -EINVAL;
 
 	mutex_lock(&direct_mutex);
-	err = __modify_ftrace_direct_multi(ops, addr);
+	err = __modify_ftrace_direct(ops, addr);
 	mutex_unlock(&direct_mutex);
 	return err;
 }
-EXPORT_SYMBOL_GPL(modify_ftrace_direct_multi);
+EXPORT_SYMBOL_GPL(modify_ftrace_direct);
 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
 
 /**
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 9ce80b3ad06d..84cd7ba31d27 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -872,7 +872,8 @@ trace_selftest_startup_function_graph(struct tracer *trace,
 	 * and make sure we get graph trace.
 	 */
 	ftrace_set_filter_ip(&direct, (unsigned long)DYN_FTRACE_TEST_NAME, 0, 0);
-	ret = register_ftrace_direct_multi(&direct, (unsigned long)trace_direct_tramp);
+	ret = register_ftrace_direct(&direct,
+				     (unsigned long)trace_direct_tramp);
 	if (ret)
 		goto out;
 
@@ -892,9 +893,9 @@ trace_selftest_startup_function_graph(struct tracer *trace,
 
 	unregister_ftrace_graph(&fgraph_ops);
 
-	ret = unregister_ftrace_direct_multi(&direct,
-					     (unsigned long) trace_direct_tramp,
-					     true);
+	ret = unregister_ftrace_direct(&direct,
+				       (unsigned long) trace_direct_tramp,
+				       true);
 	if (ret)
 		goto out;
 
diff --git a/samples/Kconfig b/samples/Kconfig
index 30ef8bd48ba3..fd24daa99f34 100644
--- a/samples/Kconfig
+++ b/samples/Kconfig
@@ -38,7 +38,7 @@ config SAMPLE_FTRACE_DIRECT
 	  that hooks to wake_up_process and prints the parameters.
 
 config SAMPLE_FTRACE_DIRECT_MULTI
-	tristate "Build register_ftrace_direct_multi() example"
+	tristate "Build register_ftrace_direct() on multiple ips example"
 	depends on DYNAMIC_FTRACE_WITH_DIRECT_CALLS && m
 	depends on HAVE_SAMPLE_FTRACE_DIRECT_MULTI
 	help
diff --git a/samples/ftrace/ftrace-direct-modify.c b/samples/ftrace/ftrace-direct-modify.c
index f01ac74bac10..25fba66f61c0 100644
--- a/samples/ftrace/ftrace-direct-modify.c
+++ b/samples/ftrace/ftrace-direct-modify.c
@@ -116,7 +116,7 @@ static int simple_thread(void *arg)
 		if (ret)
 			continue;
 		t ^= 1;
-		ret = modify_ftrace_direct_multi(&direct, tramps[t]);
+		ret = modify_ftrace_direct(&direct, tramps[t]);
 		if (!ret)
 			my_tramp = tramps[t];
 		WARN_ON_ONCE(ret);
@@ -132,7 +132,7 @@ static int __init ftrace_direct_init(void)
 	int ret;
 
 	ftrace_set_filter_ip(&direct, (unsigned long) my_ip, 0, 0);
-	ret = register_ftrace_direct_multi(&direct, my_tramp);
+	ret = register_ftrace_direct(&direct, my_tramp);
 
 	if (!ret)
 		simple_tsk = kthread_run(simple_thread, NULL, "event-sample-fn");
@@ -142,12 +142,12 @@ static int __init ftrace_direct_init(void)
 static void __exit ftrace_direct_exit(void)
 {
 	kthread_stop(simple_tsk);
-	unregister_ftrace_direct_multi(&direct, my_tramp, true);
+	unregister_ftrace_direct(&direct, my_tramp, true);
 }
 
 module_init(ftrace_direct_init);
 module_exit(ftrace_direct_exit);
 
 MODULE_AUTHOR("Steven Rostedt");
-MODULE_DESCRIPTION("Example use case of using modify_ftrace_direct_multi()");
+MODULE_DESCRIPTION("Example use case of using modify_ftrace_direct()");
 MODULE_LICENSE("GPL");
diff --git a/samples/ftrace/ftrace-direct-multi-modify.c b/samples/ftrace/ftrace-direct-multi-modify.c
index 196b43971cb5..f72623899602 100644
--- a/samples/ftrace/ftrace-direct-multi-modify.c
+++ b/samples/ftrace/ftrace-direct-multi-modify.c
@@ -123,7 +123,7 @@ static int simple_thread(void *arg)
 		if (ret)
 			continue;
 		t ^= 1;
-		ret = modify_ftrace_direct_multi(&direct, tramps[t]);
+		ret = modify_ftrace_direct(&direct, tramps[t]);
 		if (!ret)
 			my_tramp = tramps[t];
 		WARN_ON_ONCE(ret);
@@ -141,7 +141,7 @@ static int __init ftrace_direct_multi_init(void)
 	ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0);
 	ftrace_set_filter_ip(&direct, (unsigned long) schedule, 0, 0);
 
-	ret = register_ftrace_direct_multi(&direct, my_tramp);
+	ret = register_ftrace_direct(&direct, my_tramp);
 
 	if (!ret)
 		simple_tsk = kthread_run(simple_thread, NULL, "event-sample-fn");
@@ -151,12 +151,12 @@ static int __init ftrace_direct_multi_init(void)
 static void __exit ftrace_direct_multi_exit(void)
 {
 	kthread_stop(simple_tsk);
-	unregister_ftrace_direct_multi(&direct, my_tramp, true);
+	unregister_ftrace_direct(&direct, my_tramp, true);
 }
 
 module_init(ftrace_direct_multi_init);
 module_exit(ftrace_direct_multi_exit);
 
 MODULE_AUTHOR("Jiri Olsa");
-MODULE_DESCRIPTION("Example use case of using modify_ftrace_direct_multi()");
+MODULE_DESCRIPTION("Example use case of using modify_ftrace_direct()");
 MODULE_LICENSE("GPL");
diff --git a/samples/ftrace/ftrace-direct-multi.c b/samples/ftrace/ftrace-direct-multi.c
index ea0e88ee5e43..1547c2c6be02 100644
--- a/samples/ftrace/ftrace-direct-multi.c
+++ b/samples/ftrace/ftrace-direct-multi.c
@@ -73,12 +73,12 @@ static int __init ftrace_direct_multi_init(void)
 	ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0);
 	ftrace_set_filter_ip(&direct, (unsigned long) schedule, 0, 0);
 
-	return register_ftrace_direct_multi(&direct, (unsigned long) my_tramp);
+	return register_ftrace_direct(&direct, (unsigned long) my_tramp);
 }
 
 static void __exit ftrace_direct_multi_exit(void)
 {
-	unregister_ftrace_direct_multi(&direct, (unsigned long) my_tramp, true);
+	unregister_ftrace_direct(&direct, (unsigned long) my_tramp, true);
 }
 
 module_init(ftrace_direct_multi_init);
diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c
index 05c3585ac15e..f28e7b99840f 100644
--- a/samples/ftrace/ftrace-direct-too.c
+++ b/samples/ftrace/ftrace-direct-too.c
@@ -76,17 +76,17 @@ static int __init ftrace_direct_init(void)
 {
 	ftrace_set_filter_ip(&direct, (unsigned long) handle_mm_fault, 0, 0);
 
-	return register_ftrace_direct_multi(&direct, (unsigned long) my_tramp);
+	return register_ftrace_direct(&direct, (unsigned long) my_tramp);
 }
 
 static void __exit ftrace_direct_exit(void)
 {
-	unregister_ftrace_direct_multi(&direct, (unsigned long)my_tramp, true);
+	unregister_ftrace_direct(&direct, (unsigned long)my_tramp, true);
 }
 
 module_init(ftrace_direct_init);
 module_exit(ftrace_direct_exit);
 
 MODULE_AUTHOR("Steven Rostedt");
-MODULE_DESCRIPTION("Another example use case of using register_ftrace_direct_multi()");
+MODULE_DESCRIPTION("Another example use case of using register_ftrace_direct()");
 MODULE_LICENSE("GPL");
diff --git a/samples/ftrace/ftrace-direct.c b/samples/ftrace/ftrace-direct.c
index 42ec9e39453b..d81a9473b585 100644
--- a/samples/ftrace/ftrace-direct.c
+++ b/samples/ftrace/ftrace-direct.c
@@ -69,17 +69,17 @@ static int __init ftrace_direct_init(void)
 {
 	ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0);
 
-	return register_ftrace_direct_multi(&direct, (unsigned long) my_tramp);
+	return register_ftrace_direct(&direct, (unsigned long) my_tramp);
 }
 
 static void __exit ftrace_direct_exit(void)
 {
-	unregister_ftrace_direct_multi(&direct, (unsigned long)my_tramp, true);
+	unregister_ftrace_direct(&direct, (unsigned long)my_tramp, true);
 }
 
 module_init(ftrace_direct_init);
 module_exit(ftrace_direct_exit);
 
 MODULE_AUTHOR("Steven Rostedt");
-MODULE_DESCRIPTION("Example use case of using register_ftrace_direct_multi()");
+MODULE_DESCRIPTION("Example use case of using register_ftrace_direct()");
 MODULE_LICENSE("GPL");
-- 
cgit 


From dbaccb618fabde8b8596e341f8d76da63a9b0c2f Mon Sep 17 00:00:00 2001
From: Florent Revest <revest@chromium.org>
Date: Tue, 21 Mar 2023 15:04:22 +0100
Subject: ftrace: Store direct called addresses in their ops

All direct calls are now registered using the register_ftrace_direct API
so each ops can jump to only one direct-called trampoline.

By storing the direct called trampoline address directly in the ops we
can save one hashmap lookup in the direct call ops and implement arm64
direct calls on top of call ops.

Link: https://lkml.kernel.org/r/20230321140424.345218-6-revest@chromium.org

Signed-off-by: Florent Revest <revest@chromium.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 include/linux/ftrace.h | 3 +++
 kernel/trace/ftrace.c  | 7 +++++--
 2 files changed, 8 insertions(+), 2 deletions(-)

(limited to 'kernel/trace/ftrace.c')

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index abee60865fc7..6a532dd6789e 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -321,6 +321,9 @@ struct ftrace_ops {
 	unsigned long			trampoline_size;
 	struct list_head		list;
 	ftrace_ops_func_t		ops_func;
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+	unsigned long			direct_call;
+#endif
 #endif
 };
 
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 845c4012630f..3bef2abc037a 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2583,9 +2583,8 @@ ftrace_add_rec_direct(unsigned long ip, unsigned long addr,
 static void call_direct_funcs(unsigned long ip, unsigned long pip,
 			      struct ftrace_ops *ops, struct ftrace_regs *fregs)
 {
-	unsigned long addr;
+	unsigned long addr = READ_ONCE(ops->direct_call);
 
-	addr = ftrace_find_rec_direct(ip);
 	if (!addr)
 		return;
 
@@ -5381,6 +5380,7 @@ int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
 	ops->func = call_direct_funcs;
 	ops->flags = MULTI_FLAGS;
 	ops->trampoline = FTRACE_REGS_ADDR;
+	ops->direct_call = addr;
 
 	err = register_ftrace_function_nolock(ops);
 
@@ -5455,6 +5455,7 @@ __modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
 	/* Enable the tmp_ops to have the same functions as the direct ops */
 	ftrace_ops_init(&tmp_ops);
 	tmp_ops.func_hash = ops->func_hash;
+	tmp_ops.direct_call = addr;
 
 	err = register_ftrace_function_nolock(&tmp_ops);
 	if (err)
@@ -5476,6 +5477,8 @@ __modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
 			entry->direct = addr;
 		}
 	}
+	/* Prevent store tearing if a trampoline concurrently accesses the value */
+	WRITE_ONCE(ops->direct_call, addr);
 
 	mutex_unlock(&ftrace_lock);
 
-- 
cgit 


From 60c8971899f3b34ad24857913c0784dab08962f0 Mon Sep 17 00:00:00 2001
From: Florent Revest <revest@chromium.org>
Date: Tue, 21 Mar 2023 15:04:23 +0100
Subject: ftrace: Make DIRECT_CALLS work WITH_ARGS and !WITH_REGS

Direct called trampolines can be called in two ways:
- either from the ftrace callsite. In this case, they do not access any
  struct ftrace_regs nor pt_regs
- Or, if a ftrace ops is also attached, from the end of a ftrace
  trampoline. In this case, the call_direct_funcs ops is in charge of
  setting the direct call trampoline's address in a struct ftrace_regs

Since:

commit 9705bc709604 ("ftrace: pass fregs to arch_ftrace_set_direct_caller()")

The later case no longer requires a full pt_regs. It only needs a struct
ftrace_regs so DIRECT_CALLS can work with both WITH_ARGS or WITH_REGS.
With architectures like arm64 already abandoning WITH_REGS in favor of
WITH_ARGS, it's important to have DIRECT_CALLS work WITH_ARGS only.

Link: https://lkml.kernel.org/r/20230321140424.345218-7-revest@chromium.org

Signed-off-by: Florent Revest <revest@chromium.org>
Co-developed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 include/linux/ftrace.h | 6 ++++++
 kernel/trace/Kconfig   | 2 +-
 kernel/trace/ftrace.c  | 2 +-
 3 files changed, 8 insertions(+), 2 deletions(-)

(limited to 'kernel/trace/ftrace.c')

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 6a532dd6789e..31f1e1df2af3 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -241,6 +241,12 @@ enum {
 	FTRACE_OPS_FL_DIRECT			= BIT(17),
 };
 
+#ifndef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
+#define FTRACE_OPS_FL_SAVE_ARGS                        FTRACE_OPS_FL_SAVE_REGS
+#else
+#define FTRACE_OPS_FL_SAVE_ARGS                        0
+#endif
+
 /*
  * FTRACE_OPS_CMD_* commands allow the ftrace core logic to request changes
  * to a ftrace_ops. Note, the requests may fail.
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index a856d4a34c67..5b1e7fa41ca8 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -257,7 +257,7 @@ config DYNAMIC_FTRACE_WITH_REGS
 
 config DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 	def_bool y
-	depends on DYNAMIC_FTRACE_WITH_REGS
+	depends on DYNAMIC_FTRACE_WITH_REGS || DYNAMIC_FTRACE_WITH_ARGS
 	depends on HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 
 config DYNAMIC_FTRACE_WITH_CALL_OPS
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 3bef2abc037a..3b46dba3f69b 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5288,7 +5288,7 @@ static LIST_HEAD(ftrace_direct_funcs);
 
 static int register_ftrace_function_nolock(struct ftrace_ops *ops);
 
-#define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS)
+#define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_ARGS)
 
 static int check_direct_multi(struct ftrace_ops *ops)
 {
-- 
cgit 


From e11b521a7b69c2621bb2e5920bb96f6d2facdc7e Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
Date: Tue, 24 Jan 2023 09:56:53 -0500
Subject: ftrace: Show a list of all functions that have ever been enabled

When debugging a crash that appears to be related to ftrace, but not for
sure, it is useful to know if a function was ever enabled by ftrace or
not. It could be that a BPF program was attached to it, or possibly a live
patch.

We are having crashes in the field where this information is not always
known. But having ftrace set a flag if a function has ever been attached
since boot up helps tremendously in trying to know if a crash had to do
with something using ftrace.

For analyzing crashes, the use of a kdump image can have access to the
flags. When looking at issues where the kernel did not panic, the
touched_functions file can simply be used.

Link: https://lore.kernel.org/linux-trace-kernel/20230124095653.6fd1640e@gandalf.local.home

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Chris Li <chriscli@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 include/linux/ftrace.h |  5 ++++-
 kernel/trace/ftrace.c  | 51 +++++++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 50 insertions(+), 6 deletions(-)

(limited to 'kernel/trace/ftrace.c')

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 931f3d904529..327046f1278d 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -548,6 +548,7 @@ bool is_ftrace_trampoline(unsigned long addr);
  *  DIRECT   - there is a direct function to call
  *  CALL_OPS - the record can use callsite-specific ops
  *  CALL_OPS_EN - the function is set up to use callsite-specific ops
+ *  TOUCHED  - A callback was added since boot up
  *
  * When a new ftrace_ops is registered and wants a function to save
  * pt_regs, the rec->flags REGS is set. When the function has been
@@ -567,9 +568,10 @@ enum {
 	FTRACE_FL_DIRECT_EN	= (1UL << 23),
 	FTRACE_FL_CALL_OPS	= (1UL << 22),
 	FTRACE_FL_CALL_OPS_EN	= (1UL << 21),
+	FTRACE_FL_TOUCHED	= (1UL << 20),
 };
 
-#define FTRACE_REF_MAX_SHIFT	21
+#define FTRACE_REF_MAX_SHIFT	20
 #define FTRACE_REF_MAX		((1UL << FTRACE_REF_MAX_SHIFT) - 1)
 
 #define ftrace_rec_count(rec)	((rec)->flags & FTRACE_REF_MAX)
@@ -628,6 +630,7 @@ enum {
 	FTRACE_ITER_PROBE	= (1 << 4),
 	FTRACE_ITER_MOD		= (1 << 5),
 	FTRACE_ITER_ENABLED	= (1 << 6),
+	FTRACE_ITER_TOUCHED	= (1 << 7),
 };
 
 void arch_ftrace_update_code(int command);
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 3b46dba3f69b..db8532a4d5c8 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -45,6 +45,9 @@
 #include "trace_output.h"
 #include "trace_stat.h"
 
+/* Flags that do not get reset */
+#define FTRACE_NOCLEAR_FLAGS	(FTRACE_FL_DISABLED | FTRACE_FL_TOUCHED)
+
 #define FTRACE_INVALID_FUNCTION		"__ftrace_invalid_address__"
 
 #define FTRACE_WARN_ON(cond)			\
@@ -2256,7 +2259,7 @@ static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
 		flag ^= rec->flags & FTRACE_FL_ENABLED;
 
 		if (update) {
-			rec->flags |= FTRACE_FL_ENABLED;
+			rec->flags |= FTRACE_FL_ENABLED | FTRACE_FL_TOUCHED;
 			if (flag & FTRACE_FL_REGS) {
 				if (rec->flags & FTRACE_FL_REGS)
 					rec->flags |= FTRACE_FL_REGS_EN;
@@ -2326,7 +2329,7 @@ static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
 	if (update) {
 		/* If there's no more users, clear all flags */
 		if (!ftrace_rec_count(rec))
-			rec->flags &= FTRACE_FL_DISABLED;
+			rec->flags &= FTRACE_NOCLEAR_FLAGS;
 		else
 			/*
 			 * Just disable the record, but keep the ops TRAMP
@@ -3147,7 +3150,7 @@ int ftrace_shutdown(struct ftrace_ops *ops, int command)
 		struct dyn_ftrace *rec;
 
 		do_for_each_ftrace_rec(pg, rec) {
-			if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
+			if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_NOCLEAR_FLAGS))
 				pr_warn("  %pS flags:%lx\n",
 					(void *)rec->ip, rec->flags);
 		} while_for_each_ftrace_rec();
@@ -3598,7 +3601,10 @@ t_func_next(struct seq_file *m, loff_t *pos)
 		     !ftrace_lookup_ip(iter->hash, rec->ip)) ||
 
 		    ((iter->flags & FTRACE_ITER_ENABLED) &&
-		     !(rec->flags & FTRACE_FL_ENABLED))) {
+		     !(rec->flags & FTRACE_FL_ENABLED)) ||
+
+		    ((iter->flags & FTRACE_ITER_TOUCHED) &&
+		     !(rec->flags & FTRACE_FL_TOUCHED))) {
 
 			rec = NULL;
 			goto retry;
@@ -3857,7 +3863,7 @@ static int t_show(struct seq_file *m, void *v)
 		return 0;
 	}
 
-	if (iter->flags & FTRACE_ITER_ENABLED) {
+	if (iter->flags & (FTRACE_ITER_ENABLED | FTRACE_ITER_TOUCHED)) {
 		struct ftrace_ops *ops;
 
 		seq_printf(m, " (%ld)%s%s%s%s",
@@ -3959,6 +3965,31 @@ ftrace_enabled_open(struct inode *inode, struct file *file)
 	return 0;
 }
 
+static int
+ftrace_touched_open(struct inode *inode, struct file *file)
+{
+	struct ftrace_iterator *iter;
+
+	/*
+	 * This shows us what functions have ever been enabled
+	 * (traced, direct, patched, etc). Not sure if we want lockdown
+	 * to hide such critical information for an admin.
+	 * Although, perhaps it can show information we don't
+	 * want people to see, but if something had traced
+	 * something, we probably want to know about it.
+	 */
+
+	iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
+	if (!iter)
+		return -ENOMEM;
+
+	iter->pg = ftrace_pages_start;
+	iter->flags = FTRACE_ITER_TOUCHED;
+	iter->ops = &global_ops;
+
+	return 0;
+}
+
 /**
  * ftrace_regex_open - initialize function tracer filter files
  * @ops: The ftrace_ops that hold the hash filters
@@ -5872,6 +5903,13 @@ static const struct file_operations ftrace_enabled_fops = {
 	.release = seq_release_private,
 };
 
+static const struct file_operations ftrace_touched_fops = {
+	.open = ftrace_touched_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = seq_release_private,
+};
+
 static const struct file_operations ftrace_filter_fops = {
 	.open = ftrace_filter_open,
 	.read = seq_read,
@@ -6336,6 +6374,9 @@ static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
 	trace_create_file("enabled_functions", TRACE_MODE_READ,
 			d_tracer, NULL, &ftrace_enabled_fops);
 
+	trace_create_file("touched_functions", TRACE_MODE_READ,
+			d_tracer, NULL, &ftrace_touched_fops);
+
 	ftrace_create_filter_files(&global_ops, d_tracer);
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
-- 
cgit 


From 6ce2c04fcbcaa5eb086e5142ab359be306cbc3e1 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
Date: Tue, 2 May 2023 21:32:33 -0400
Subject: ftrace: Add MODIFIED flag to show if IPMODIFY or direct was attached

If a function had ever had IPMODIFY or DIRECT attached to it, where this
is how live kernel patching and BPF overrides work, mark them and display
an "M" in the enabled_functions and touched_functions files. This can be
used for debugging. If a function had been modified and later there's a bug
in the code related to that function, this can be used to know if the cause
is possibly from a live kernel patch or a BPF program that changed the
behavior of the code.

Also update the documentation on the enabled_functions and
touched_functions output, as it was missing direct callers and CALL_OPS.
And include this new modify attribute.

Link: https://lore.kernel.org/linux-trace-kernel/20230502213233.004e3ae4@gandalf.local.home

Cc: Mark Rutland <mark.rutland@arm.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 Documentation/trace/ftrace.rst | 25 +++++++++++++++++++++++++
 include/linux/ftrace.h         |  4 +++-
 kernel/trace/ftrace.c          | 12 +++++++++---
 3 files changed, 37 insertions(+), 4 deletions(-)

(limited to 'kernel/trace/ftrace.c')

diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst
index aaebb821912e..d5766229c71a 100644
--- a/Documentation/trace/ftrace.rst
+++ b/Documentation/trace/ftrace.rst
@@ -350,6 +350,19 @@ of ftrace. Here is a list of some of the key files:
 	an 'I' will be displayed on the same line as the function that
 	can be overridden.
 
+	If a non ftrace trampoline is attached (BPF) a 'D' will be displayed.
+	Note, normal ftrace trampolines can also be attached, but only one
+	"direct" trampoline can be attached to a given function at a time.
+
+	Some architectures can not call direct trampolines, but instead have
+	the ftrace ops function located above the function entry point. In
+	such cases an 'O' will be displayed.
+
+	If a function had either the "ip modify" or a "direct" call attached to
+	it in the past, a 'M' will be shown. This flag is never cleared. It is
+	used to know if a function was every modified by the ftrace infrastructure,
+	and can be used for debugging.
+
 	If the architecture supports it, it will also show what callback
 	is being directly called by the function. If the count is greater
 	than 1 it most likely will be ftrace_ops_list_func().
@@ -359,6 +372,18 @@ of ftrace. Here is a list of some of the key files:
 	its address will be printed as well as the function that the
 	trampoline calls.
 
+  touched_functions:
+
+	This file contains all the functions that ever had a function callback
+	to it via the ftrace infrastructure. It has the same format as
+	enabled_functions but shows all functions that have every been
+	traced.
+
+	To see any function that has every been modified by "ip modify" or a
+	direct trampoline, one can perform the following command:
+
+	grep ' M ' /sys/kernel/tracing/touched_functions
+
   function_profile_enabled:
 
 	When set it will enable all functions with either the function
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 327046f1278d..7dffd740e784 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -549,6 +549,7 @@ bool is_ftrace_trampoline(unsigned long addr);
  *  CALL_OPS - the record can use callsite-specific ops
  *  CALL_OPS_EN - the function is set up to use callsite-specific ops
  *  TOUCHED  - A callback was added since boot up
+ *  MODIFIED - The function had IPMODIFY or DIRECT attached to it
  *
  * When a new ftrace_ops is registered and wants a function to save
  * pt_regs, the rec->flags REGS is set. When the function has been
@@ -569,9 +570,10 @@ enum {
 	FTRACE_FL_CALL_OPS	= (1UL << 22),
 	FTRACE_FL_CALL_OPS_EN	= (1UL << 21),
 	FTRACE_FL_TOUCHED	= (1UL << 20),
+	FTRACE_FL_MODIFIED	= (1UL << 19),
 };
 
-#define FTRACE_REF_MAX_SHIFT	20
+#define FTRACE_REF_MAX_SHIFT	19
 #define FTRACE_REF_MAX		((1UL << FTRACE_REF_MAX_SHIFT) - 1)
 
 #define ftrace_rec_count(rec)	((rec)->flags & FTRACE_REF_MAX)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index db8532a4d5c8..885845fc851d 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -46,7 +46,8 @@
 #include "trace_stat.h"
 
 /* Flags that do not get reset */
-#define FTRACE_NOCLEAR_FLAGS	(FTRACE_FL_DISABLED | FTRACE_FL_TOUCHED)
+#define FTRACE_NOCLEAR_FLAGS	(FTRACE_FL_DISABLED | FTRACE_FL_TOUCHED | \
+				 FTRACE_FL_MODIFIED)
 
 #define FTRACE_INVALID_FUNCTION		"__ftrace_invalid_address__"
 
@@ -2273,6 +2274,10 @@ static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
 					rec->flags &= ~FTRACE_FL_TRAMP_EN;
 			}
 
+			/* Keep track of anything that modifies the function */
+			if (rec->flags & (FTRACE_FL_DIRECT | FTRACE_FL_IPMODIFY))
+				rec->flags |= FTRACE_FL_MODIFIED;
+
 			if (flag & FTRACE_FL_DIRECT) {
 				/*
 				 * If there's only one user (direct_ops helper)
@@ -3866,12 +3871,13 @@ static int t_show(struct seq_file *m, void *v)
 	if (iter->flags & (FTRACE_ITER_ENABLED | FTRACE_ITER_TOUCHED)) {
 		struct ftrace_ops *ops;
 
-		seq_printf(m, " (%ld)%s%s%s%s",
+		seq_printf(m, " (%ld)%s%s%s%s%s",
 			   ftrace_rec_count(rec),
 			   rec->flags & FTRACE_FL_REGS ? " R" : "  ",
 			   rec->flags & FTRACE_FL_IPMODIFY ? " I" : "  ",
 			   rec->flags & FTRACE_FL_DIRECT ? " D" : "  ",
-			   rec->flags & FTRACE_FL_CALL_OPS ? " O" : "  ");
+			   rec->flags & FTRACE_FL_CALL_OPS ? " O" : "  ",
+			   rec->flags & FTRACE_FL_MODIFIED ? " M " : "   ");
 		if (rec->flags & FTRACE_FL_TRAMP_EN) {
 			ops = ftrace_find_tramp_ops_any(rec);
 			if (ops) {
-- 
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