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From: Peter Zijlstra <peterz@infradead.org>
To: x86@kernel.org
Cc: peterz@infradead.org, linux-kernel@vger.kernel.org,
	rostedt@goodmis.org, mhiramat@kernel.org, bristot@redhat.com,
	jbaron@akamai.com, torvalds@linux-foundation.org,
	tglx@linutronix.de, mingo@kernel.org, namit@vmware.com,
	hpa@zytor.com, luto@kernel.org, ard.biesheuvel@linaro.org,
	jpoimboe@redhat.com, jeyu@kernel.org
Subject: [PATCH v4 16/16] ftrace: Merge ftrace_module_{init,enable}()
Date: Fri, 18 Oct 2019 09:35:41 +0200	[thread overview]
Message-ID: <20191018074634.858645375@infradead.org> (raw)
In-Reply-To: <20191018073525.768931536@infradead.org>

Because of how some architectures used set_all_modules_text_*() there
was a dependency between the module state and its memory protection
state. This then required ftrace to be split into two functions, see
commit:

  a949ae560a51 ("ftrace/module: Hardcode ftrace_module_init() call into load_module()")

Now that set_all_modules_text_*() is dead and burried, this is no
longer relevant and we can merge the ftrace_module hooks again.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
---
 include/linux/ftrace.h |    2 
 kernel/module.c        |    3 -
 kernel/trace/ftrace.c  |  124 +++++++++++++++++++------------------------------
 3 files changed, 49 insertions(+), 80 deletions(-)

--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -579,7 +579,6 @@ static inline int ftrace_modify_call(str
 extern int ftrace_arch_read_dyn_info(char *buf, int size);
 
 extern int skip_trace(unsigned long ip);
-extern void ftrace_module_init(struct module *mod);
 extern void ftrace_module_enable(struct module *mod);
 extern void ftrace_release_mod(struct module *mod);
 
@@ -590,7 +589,6 @@ static inline int skip_trace(unsigned lo
 static inline int ftrace_force_update(void) { return 0; }
 static inline void ftrace_disable_daemon(void) { }
 static inline void ftrace_enable_daemon(void) { }
-static inline void ftrace_module_init(struct module *mod) { }
 static inline void ftrace_module_enable(struct module *mod) { }
 static inline void ftrace_release_mod(struct module *mod) { }
 static inline int ftrace_text_reserved(const void *start, const void *end)
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3836,9 +3836,6 @@ static int load_module(struct load_info
 
 	dynamic_debug_setup(mod, info->debug, info->num_debug);
 
-	/* Ftrace init must be called in the MODULE_STATE_UNFORMED state */
-	ftrace_module_init(mod);
-
 	/* Finally it's fully formed, ready to start executing. */
 	err = complete_formation(mod, info);
 	if (err)
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5564,6 +5564,8 @@ static int ftrace_cmp_ips(const void *a,
 	return 0;
 }
 
+static int referenced_filters(struct dyn_ftrace *rec);
+
 static int ftrace_process_locs(struct module *mod,
 			       unsigned long *start,
 			       unsigned long *end)
@@ -5656,6 +5658,49 @@ static int ftrace_process_locs(struct mo
 	ftrace_update_code(mod, start_pg);
 	if (!mod)
 		local_irq_restore(flags);
+
+#ifdef CONFIG_MODULES
+	if (ftrace_disabled || !mod)
+		goto out_loop;
+
+	do_for_each_ftrace_rec(pg, rec) {
+		int cnt;
+		/*
+		 * do_for_each_ftrace_rec() is a double loop.
+		 * module text shares the pg. If a record is
+		 * not part of this module, then skip this pg,
+		 * which the "break" will do.
+		 */
+		if (!within_module_core(rec->ip, mod) &&
+		    !within_module_init(rec->ip, mod))
+			break;
+
+		cnt = 0;
+
+		/*
+		 * When adding a module, we need to check if tracers are
+		 * currently enabled and if they are, and can trace this record,
+		 * we need to enable the module functions as well as update the
+		 * reference counts for those function records.
+		 */
+		if (ftrace_start_up)
+			cnt += referenced_filters(rec);
+
+		/* This clears FTRACE_FL_DISABLED */
+		rec->flags = cnt;
+
+		if (ftrace_start_up && cnt) {
+			int failed = __ftrace_replace_code(rec, 1);
+			if (failed) {
+				ftrace_bug(failed, rec);
+				goto out_loop;
+			}
+		}
+
+	} while_for_each_ftrace_rec();
+
+ out_loop:
+#endif
 	ret = 0;
  out:
 	mutex_unlock(&ftrace_lock);
@@ -5823,85 +5868,14 @@ void ftrace_release_mod(struct module *m
 
 void ftrace_module_enable(struct module *mod)
 {
-	struct dyn_ftrace *rec;
-	struct ftrace_page *pg;
-
-	mutex_lock(&ftrace_lock);
-
-	if (ftrace_disabled)
-		goto out_unlock;
-
-	/*
-	 * If the tracing is enabled, go ahead and enable the record.
-	 *
-	 * The reason not to enable the record immediately is the
-	 * inherent check of ftrace_make_nop/ftrace_make_call for
-	 * correct previous instructions.  Making first the NOP
-	 * conversion puts the module to the correct state, thus
-	 * passing the ftrace_make_call check.
-	 *
-	 * We also delay this to after the module code already set the
-	 * text to read-only, as we now need to set it back to read-write
-	 * so that we can modify the text.
-	 */
-	if (ftrace_start_up)
-		ftrace_arch_code_modify_prepare();
-
-	do_for_each_ftrace_rec(pg, rec) {
-		int cnt;
-		/*
-		 * do_for_each_ftrace_rec() is a double loop.
-		 * module text shares the pg. If a record is
-		 * not part of this module, then skip this pg,
-		 * which the "break" will do.
-		 */
-		if (!within_module_core(rec->ip, mod) &&
-		    !within_module_init(rec->ip, mod))
-			break;
-
-		cnt = 0;
-
-		/*
-		 * When adding a module, we need to check if tracers are
-		 * currently enabled and if they are, and can trace this record,
-		 * we need to enable the module functions as well as update the
-		 * reference counts for those function records.
-		 */
-		if (ftrace_start_up)
-			cnt += referenced_filters(rec);
-
-		/* This clears FTRACE_FL_DISABLED */
-		rec->flags = cnt;
-
-		if (ftrace_start_up && cnt) {
-			int failed = __ftrace_replace_code(rec, 1);
-			if (failed) {
-				ftrace_bug(failed, rec);
-				goto out_loop;
-			}
-		}
-
-	} while_for_each_ftrace_rec();
-
- out_loop:
-	if (ftrace_start_up)
-		ftrace_arch_code_modify_post_process();
-
- out_unlock:
-	mutex_unlock(&ftrace_lock);
+	if (!(ftrace_disabled || !mod->num_ftrace_callsites)) {
+		ftrace_process_locs(mod, mod->ftrace_callsites,
+				    mod->ftrace_callsites + mod->num_ftrace_callsites);
+	}
 
 	process_cached_mods(mod->name);
 }
 
-void ftrace_module_init(struct module *mod)
-{
-	if (ftrace_disabled || !mod->num_ftrace_callsites)
-		return;
-
-	ftrace_process_locs(mod, mod->ftrace_callsites,
-			    mod->ftrace_callsites + mod->num_ftrace_callsites);
-}
-
 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
 				struct dyn_ftrace *rec)
 {



  parent reply	other threads:[~2019-10-18  7:52 UTC|newest]

Thread overview: 70+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-18  7:35 [PATCH v4 00/16] Rewrite x86/ftrace to use text_poke (and more) Peter Zijlstra
2019-10-18  7:35 ` [PATCH v4 01/16] x86/alternatives: Teach text_poke_bp() to emulate instructions Peter Zijlstra
2019-10-18  7:35 ` [PATCH v4 02/16] x86/alternatives: Update int3_emulate_push() comment Peter Zijlstra
2019-10-18  7:35 ` [PATCH v4 03/16] x86/alternatives,jump_label: Provide better text_poke() batching interface Peter Zijlstra
2019-10-21  8:48   ` Ingo Molnar
2019-10-21  9:21     ` Peter Zijlstra
2019-10-18  7:35 ` [PATCH v4 04/16] x86/alternatives: Add and use text_gen_insn() helper Peter Zijlstra
2019-10-18  7:35 ` [PATCH v4 05/16] x86/ftrace: Use text_poke() Peter Zijlstra
2019-10-18  7:35 ` [PATCH v4 06/16] x86/mm: Remove set_kernel_text_r[ow]() Peter Zijlstra
2019-10-18  7:35 ` [PATCH v4 07/16] x86/alternative: Add text_opcode_size() Peter Zijlstra
2019-10-18  7:35 ` [PATCH v4 08/16] x86/ftrace: Use text_gen_insn() Peter Zijlstra
2019-10-18  7:35 ` [PATCH v4 09/16] x86/alternative: Remove text_poke_loc::len Peter Zijlstra
2019-10-21  8:58   ` Ingo Molnar
2019-10-21  9:02     ` Ingo Molnar
2019-10-18  7:35 ` [PATCH v4 10/16] x86/alternative: Shrink text_poke_loc Peter Zijlstra
2019-10-21  9:01   ` Ingo Molnar
2019-10-21  9:25     ` Peter Zijlstra
2019-10-21  9:33       ` Ingo Molnar
2019-10-18  7:35 ` [PATCH v4 11/16] x86/kprobes: Convert to text-patching.h Peter Zijlstra
2019-10-21 14:57   ` Masami Hiramatsu
2019-10-18  7:35 ` [PATCH v4 12/16] x86/kprobes: Fix ordering Peter Zijlstra
2019-10-22  1:35   ` Masami Hiramatsu
2019-10-22 10:31     ` Peter Zijlstra
2019-10-18  7:35 ` [PATCH v4 13/16] arm/ftrace: Use __patch_text_real() Peter Zijlstra
2019-10-28 16:25   ` Will Deacon
2019-10-28 16:34     ` Peter Zijlstra
2019-10-28 16:35       ` Peter Zijlstra
2019-10-28 16:47       ` Will Deacon
2019-10-28 16:55         ` Peter Zijlstra
2019-10-18  7:35 ` [PATCH v4 14/16] module: Remove set_all_modules_text_*() Peter Zijlstra
2019-10-18  7:35 ` [PATCH v4 15/16] module: Move where we mark modules RO,X Peter Zijlstra
2019-10-21 13:53   ` Josh Poimboeuf
2019-10-21 14:14     ` Peter Zijlstra
2019-10-21 15:34       ` Peter Zijlstra
2019-10-21 15:44         ` Peter Zijlstra
2019-10-21 16:11         ` Peter Zijlstra
2019-10-22 11:31           ` Heiko Carstens
2019-10-22 12:31             ` Peter Zijlstra
2019-10-23 11:48       ` Peter Zijlstra
2019-10-23 15:16         ` Peter Zijlstra
2019-10-23 17:15           ` Josh Poimboeuf
2019-10-24 10:59             ` Peter Zijlstra
2019-10-24 18:31               ` Josh Poimboeuf
2019-10-24 20:33                 ` Peter Zijlstra
2019-10-23 17:00         ` Josh Poimboeuf
2019-10-24 13:16           ` Peter Zijlstra
2019-10-25  6:44             ` Petr Mladek
2019-10-25  8:43               ` Peter Zijlstra
2019-10-25 10:06                 ` Peter Zijlstra
2019-10-25 13:50                   ` Josh Poimboeuf
2019-10-26  1:17                   ` Josh Poimboeuf
2019-10-28 10:07                     ` Peter Zijlstra
2019-10-28 10:43                     ` Peter Zijlstra
2019-10-25  9:16               ` Peter Zijlstra
2019-10-22  2:21   ` Steven Rostedt
2019-10-22 20:24     ` Peter Zijlstra
2019-10-22 20:40       ` Steven Rostedt
2019-10-23  9:07         ` Peter Zijlstra
2019-10-23 18:52       ` Steven Rostedt
2019-10-24 10:16         ` Peter Zijlstra
2019-10-24 10:18           ` Peter Zijlstra
2019-10-24 15:00           ` Steven Rostedt
2019-10-24 16:43             ` Peter Zijlstra
2019-10-24 18:17               ` Steven Rostedt
2019-10-24 20:24                 ` Peter Zijlstra
2019-10-24 20:28                   ` Steven Rostedt
2019-10-18  7:35 ` Peter Zijlstra [this message]
2019-10-18  8:20   ` [PATCH v4 16/16] ftrace: Merge ftrace_module_{init,enable}() Peter Zijlstra
2019-10-21  9:09 ` [PATCH v4 00/16] Rewrite x86/ftrace to use text_poke (and more) Ingo Molnar
2019-10-21 13:38   ` Steven Rostedt

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