linux-kernel - [PATCH v3 2/2] PM: enable dynamic debug support within pm_pr

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20220324080653.454333-3-dacohen@pm.me>
Date:   Thu, 24 Mar 2022 08:07:30 +0000
From:   David Cohen <dacohen@...me>
To:     rafael@...nel.org, len.brown@...el.com, pavel@....cz
Cc:     linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        David Cohen <dacohen@...me>
Subject: [PATCH v3 2/2] PM: enable dynamic debug support within pm_pr_dbg()

Currently pm_pr_dbg() is used to filter kernel pm debug messages based
on pm_debug_messages_on flag. The problem is if we enable/disable this
flag it will affect all pm_pr_dbg() calls at once, so we can't
individually control them.

This patch changes pm_pr_dbg() implementation as such:
 - If pm_debug_messages_on is enabled, print the message.
 - If pm_debug_messages_on is disabled and CONFIG_DYNAMIC_DEBUG is
   enabled, only print the messages explicitly enabled on
   /sys/kernel/debug/dynamic_debug/control.
 - If pm_debug_messages_on is disabled and CONFIG_DYNAMIC_DEBUG is
   disabled, don't print the message.

Signed-off-by: David Cohen <dacohen@...me>
---
 include/linux/suspend.h | 44 ++++++++++++++++++++++++++++++++++++-----
 kernel/power/main.c     | 29 ---------------------------
 2 files changed, 39 insertions(+), 34 deletions(-)

diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index 300273ff40cc..70f2921e2e70 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -542,22 +542,56 @@ static inline void unlock_system_sleep(void) {}
 #ifdef CONFIG_PM_SLEEP_DEBUG
 extern bool pm_print_times_enabled;
 extern bool pm_debug_messages_on;
-extern __printf(2, 3) void __pm_pr_dbg(bool defer, const char *fmt, ...);
+static inline int pm_dyn_debug_messages_on(void)
+{
+#ifdef CONFIG_DYNAMIC_DEBUG
+	return 1;
+#else
+	return 0;
+#endif
+}
+#ifndef pr_fmt
+#define pr_fmt(fmt) "PM: " fmt
+#endif
+#define __pm_pr_dbg(fmt, ...)					\
+	do {							\
+		if (pm_debug_messages_on)			\
+			printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__);	\
+		else if (pm_dyn_debug_messages_on())		\
+			pr_debug(fmt, ##__VA_ARGS__);	\
+	} while (0)
+#define __pm_deferred_pr_dbg(fmt, ...)				\
+	do {							\
+		if (pm_debug_messages_on)			\
+			printk_deferred(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__);	\
+	} while (0)
 #else
 #define pm_print_times_enabled	(false)
 #define pm_debug_messages_on	(false)

 #include <linux/printk.h>

-#define __pm_pr_dbg(defer, fmt, ...) \
-	no_printk(KERN_DEBUG fmt, ##__VA_ARGS__)
+#define __pm_pr_dbg(fmt, ...) \
+	no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
+#define __pm_deferred_pr_dbg(fmt, ...) \
+	no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
 #endif

+/**
+ * pm_pr_dbg - print pm sleep debug messages
+ *
+ * If pm_debug_messages_on is enabled, print message.
+ * If pm_debug_messages_on is disabled and CONFIG_DYNAMIC_DEBUG is enabled,
+ *	print message only from instances explicitly enabled on dynamic debug's
+ *	control.
+ * If pm_debug_messages_on is disabled and CONFIG_DYNAMIC_DEBUG is disabled,
+ *	don't print message.
+ */
 #define pm_pr_dbg(fmt, ...) \
-	__pm_pr_dbg(false, fmt, ##__VA_ARGS__)
+	__pm_pr_dbg(fmt, ##__VA_ARGS__)

 #define pm_deferred_pr_dbg(fmt, ...) \
-	__pm_pr_dbg(true, fmt, ##__VA_ARGS__)
+	__pm_deferred_pr_dbg(fmt, ##__VA_ARGS__)

 #ifdef CONFIG_PM_AUTOSLEEP

diff --git a/kernel/power/main.c b/kernel/power/main.c
index 7e646079fbeb..5242bf2ee469 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -545,35 +545,6 @@ static int __init pm_debug_messages_setup(char *str)
 }
 __setup("pm_debug_messages", pm_debug_messages_setup);

-/**
- * __pm_pr_dbg - Print a suspend debug message to the kernel log.
- * @defer: Whether or not to use printk_deferred() to print the message.
- * @fmt: Message format.
- *
- * The message will be emitted if enabled through the pm_debug_messages
- * sysfs attribute.
- */
-void __pm_pr_dbg(bool defer, const char *fmt, ...)
-{
-	struct va_format vaf;
-	va_list args;
-
-	if (!pm_debug_messages_on)
-		return;
-
-	va_start(args, fmt);
-
-	vaf.fmt = fmt;
-	vaf.va = &args;
-
-	if (defer)
-		printk_deferred(KERN_DEBUG "PM: %pV", &vaf);
-	else
-		printk(KERN_DEBUG "PM: %pV", &vaf);
-
-	va_end(args);
-}
-
 #else /* !CONFIG_PM_SLEEP_DEBUG */
 static inline void pm_print_times_init(void) {}
 #endif /* CONFIG_PM_SLEEP_DEBUG */
--
2.35.1