printk/nmi: Prevent deadlock when accessing the main log buffer in NMI

[mirror_ubuntu-bionic-kernel.git] / include / linux / printk.h

diff --git a/include/linux/printk.h b/include/linux/printk.h
index e9b603ee99532266a735555ffb784a939f18f5cf..2415ee88fee675941e7696d375b5cdc22c0b18e1 100644 (file)
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -148,9 +148,13 @@ void early_printk(const char *s, ...) { }
 #ifdef CONFIG_PRINTK_NMI
 extern void printk_nmi_enter(void);
 extern void printk_nmi_exit(void);
+extern void printk_nmi_direct_enter(void);
+extern void printk_nmi_direct_exit(void);
 #else
 static inline void printk_nmi_enter(void) { }
 static inline void printk_nmi_exit(void) { }
+static inline void printk_nmi_direct_enter(void) { }
+static inline void printk_nmi_direct_exit(void) { }
 #endif /* PRINTK_NMI */
 
 #ifdef CONFIG_PRINTK
@@ -285,6 +289,27 @@ extern asmlinkage void dump_stack(void) __cold;
 #define pr_fmt(fmt) fmt
 #endif
 
+#if defined(__KMSG_CHECKER) && defined(KMSG_COMPONENT)
+
+/* generate magic string for scripts/kmsg-doc to parse */
+#define pr_printk_hash(level, format, ...) \
+       __KMSG_PRINT(level _FMT_ format _ARGS_ __VA_ARGS__ _END_)
+
+#elif defined(CONFIG_KMSG_IDS) && defined(KMSG_COMPONENT)
+
+/* format element '%pj' prints the six digit jhash of a string */
+#define _pr_printk_hash(pfx, fmt, ...) \
+       printk(pfx fmt, pfx fmt + __builtin_strlen(pfx), ##__VA_ARGS__)
+#define pr_printk_hash(level, format, ...) \
+       _pr_printk_hash(level KMSG_COMPONENT ".%pj: ", format, ##__VA_ARGS__)
+
+#else /* !defined(CONFIG_KMSG_IDS) */
+
+#define pr_printk_hash(level, format, ...) \
+       printk(level pr_fmt(format), ##__VA_ARGS__)
+
+#endif
+
 /*
  * These can be used to print at the various log levels.
  * All of these will print unconditionally, although note that pr_debug()
@@ -292,20 +317,20 @@ extern asmlinkage void dump_stack(void) __cold;
  * or CONFIG_DYNAMIC_DEBUG is set.
  */
 #define pr_emerg(fmt, ...) \
-       printk(KERN_EMERG pr_fmt(fmt), ##__VA_ARGS__)
+       pr_printk_hash(KERN_EMERG, fmt, ##__VA_ARGS__)
 #define pr_alert(fmt, ...) \
-       printk(KERN_ALERT pr_fmt(fmt), ##__VA_ARGS__)
+       pr_printk_hash(KERN_ALERT, fmt, ##__VA_ARGS__)
 #define pr_crit(fmt, ...) \
-       printk(KERN_CRIT pr_fmt(fmt), ##__VA_ARGS__)
+       pr_printk_hash(KERN_CRIT, fmt, ##__VA_ARGS__)
 #define pr_err(fmt, ...) \
-       printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
+       pr_printk_hash(KERN_ERR, fmt, ##__VA_ARGS__)
 #define pr_warning(fmt, ...) \
-       printk(KERN_WARNING pr_fmt(fmt), ##__VA_ARGS__)
+       pr_printk_hash(KERN_WARNING, fmt, ##__VA_ARGS__)
 #define pr_warn pr_warning
 #define pr_notice(fmt, ...) \
-       printk(KERN_NOTICE pr_fmt(fmt), ##__VA_ARGS__)
+       pr_printk_hash(KERN_NOTICE, fmt, ##__VA_ARGS__)
 #define pr_info(fmt, ...) \
-       printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
+       pr_printk_hash(KERN_INFO, fmt, ##__VA_ARGS__)
 /*
  * Like KERN_CONT, pr_cont() should only be used when continuing
  * a line with no newline ('\n') enclosed. Otherwise it defaults