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authorLinus Torvalds <torvalds@linux-foundation.org>2020-10-13 15:58:10 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-10-13 15:58:10 -0700
commitd594d8f411d47bf7b583ec3474b11fec348c88bb (patch)
tree0f0df70d11f31b006684b48e5b973f9ae3a7b679 /include/linux
parent029f56db6ac248769f2c260bfaf3c3c0e23e904c (diff)
parent70333f4ff9c16dd82a2667080c3ae48fe30a3cb4 (diff)
Merge tag 'printk-for-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux
Pull printk updates from Petr Mladek: "The big new thing is the fully lockless ringbuffer implementation, including the support for continuous lines. It will allow to store and read messages in any situation wihtout the risk of deadlocks and without the need of temporary per-CPU buffers. The access is still serialized by logbuf_lock. It synchronizes few more operations, for example, temporary buffer for formatting the message, syslog and kmsg_dump operations. The lock removal is being discussed and should be ready for the next release. The continuous lines are handled exactly the same way as before to avoid regressions in user space. It means that they are appended to the last message when the caller is the same. Only the last message can be extended. The data ring includes plain text of the messages. Except for an integer at the beginning of each message that points back to the descriptor ring with other metadata. The dictionary has to stay. journalctl uses it to filter the log. It allows to show messages related to a given device. The dictionary values are stored in the descriptor ring with the other metadata. This is the first part of the printk rework as discussed at Plumbers 2019, see https://lore.kernel.org/r/87k1acz5rx.fsf@linutronix.de. The next big step will be handling consoles by kthreads during the normal system operation. It will require special handling of situations when the kthreads could not get scheduled, for example, early boot, suspend, panic. Other changes: - Add John Ogness as a reviewer for printk subsystem. He is author of the rework and is familiar with the code and history. - Fix locking in serial8250_do_startup() to prevent lockdep report. - Few code cleanups" * tag 'printk-for-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: (27 commits) printk: Use fallthrough pseudo-keyword printk: reduce setup_text_buf size to LOG_LINE_MAX printk: avoid and/or handle record truncation printk: remove dict ring printk: move dictionary keys to dev_printk_info printk: move printk_info into separate array printk: reimplement log_cont using record extension printk: ringbuffer: add finalization/extension support printk: ringbuffer: change representation of states printk: ringbuffer: clear initial reserved fields printk: ringbuffer: add BLK_DATALESS() macro printk: ringbuffer: relocate get_data() printk: ringbuffer: avoid memcpy() on state_var printk: ringbuffer: fix setting state in desc_read() kernel.h: Move oops_in_progress to printk.h scripts/gdb: update for lockless printk ringbuffer scripts/gdb: add utils.read_ulong() docs: vmcoreinfo: add lockless printk ringbuffer vmcoreinfo printk: reduce LOG_BUF_SHIFT range for H8300 printk: ringbuffer: support dataless records ...
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/crash_core.h3
-rw-r--r--include/linux/debug_locks.h2
-rw-r--r--include/linux/dev_printk.h8
-rw-r--r--include/linux/kernel.h1
-rw-r--r--include/linux/printk.h8
5 files changed, 18 insertions, 4 deletions
diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
index 6594dbc34a37..206bde8308b2 100644
--- a/include/linux/crash_core.h
+++ b/include/linux/crash_core.h
@@ -55,6 +55,9 @@ phys_addr_t paddr_vmcoreinfo_note(void);
#define VMCOREINFO_OFFSET(name, field) \
vmcoreinfo_append_str("OFFSET(%s.%s)=%lu\n", #name, #field, \
(unsigned long)offsetof(struct name, field))
+#define VMCOREINFO_TYPE_OFFSET(name, field) \
+ vmcoreinfo_append_str("OFFSET(%s.%s)=%lu\n", #name, #field, \
+ (unsigned long)offsetof(name, field))
#define VMCOREINFO_LENGTH(name, value) \
vmcoreinfo_append_str("LENGTH(%s)=%lu\n", #name, (unsigned long)value)
#define VMCOREINFO_NUMBER(name) \
diff --git a/include/linux/debug_locks.h b/include/linux/debug_locks.h
index e7e45f0cc7da..2915f56ad421 100644
--- a/include/linux/debug_locks.h
+++ b/include/linux/debug_locks.h
@@ -2,9 +2,9 @@
#ifndef __LINUX_DEBUG_LOCKING_H
#define __LINUX_DEBUG_LOCKING_H
-#include <linux/kernel.h>
#include <linux/atomic.h>
#include <linux/bug.h>
+#include <linux/printk.h>
struct task_struct;
diff --git a/include/linux/dev_printk.h b/include/linux/dev_printk.h
index 3028b644b4fb..6f009559ee54 100644
--- a/include/linux/dev_printk.h
+++ b/include/linux/dev_printk.h
@@ -21,6 +21,14 @@
struct device;
+#define PRINTK_INFO_SUBSYSTEM_LEN 16
+#define PRINTK_INFO_DEVICE_LEN 48
+
+struct dev_printk_info {
+ char subsystem[PRINTK_INFO_SUBSYSTEM_LEN];
+ char device[PRINTK_INFO_DEVICE_LEN];
+};
+
#ifdef CONFIG_PRINTK
__printf(3, 0) __cold
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index c25b8e41c0ea..e4aa29b1ad62 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -526,7 +526,6 @@ extern unsigned int sysctl_oops_all_cpu_backtrace;
#endif /* CONFIG_SMP */
extern void bust_spinlocks(int yes);
-extern int oops_in_progress; /* If set, an oops, panic(), BUG() or die() is in progress */
extern int panic_timeout;
extern unsigned long panic_print;
extern int panic_on_oops;
diff --git a/include/linux/printk.h b/include/linux/printk.h
index 34c1a7be3e01..78479633ccfc 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -12,6 +12,8 @@
extern const char linux_banner[];
extern const char linux_proc_banner[];
+extern int oops_in_progress; /* If set, an oops, panic(), BUG() or die() is in progress */
+
#define PRINTK_MAX_SINGLE_HEADER_LEN 2
static inline int printk_get_level(const char *buffer)
@@ -159,10 +161,12 @@ static inline void printk_nmi_direct_enter(void) { }
static inline void printk_nmi_direct_exit(void) { }
#endif /* PRINTK_NMI */
+struct dev_printk_info;
+
#ifdef CONFIG_PRINTK
-asmlinkage __printf(5, 0)
+asmlinkage __printf(4, 0)
int vprintk_emit(int facility, int level,
- const char *dict, size_t dictlen,
+ const struct dev_printk_info *dev_info,
const char *fmt, va_list args);
asmlinkage __printf(1, 0)