[PATCH v2] printk: move dump stack related code to lib/dump_stack.c

Dave Young
2018-02-13T07:28:44Z

dump_stack related stuff should belong to lib/dump_stack.c thus move them
there. Also conditionally compile lib/dump_stack.c since dump_stack code
does not make sense if printk is disabled.

Signed-off-by: Dave Young <dyoung@redhat.com>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Suggested-by: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
---
Note: dump stack etc still share printk.h as before, I would keep it as is
since a lot of files need it.
include/linux/printk.h | 7 ++++-
kernel/printk/printk.c | 60 -------------------------------------------------
lib/Makefile | 3 +-
lib/dump_stack.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 67 insertions(+), 63 deletions(-)

--- linux-x86.orig/kernel/printk/printk.c
+++ linux-x86/kernel/printk/printk.c
@@ -42,13 +42,11 @@
#include <linux/rculist.h>
#include <linux/poll.h>
#include <linux/irq_work.h>
-#include <linux/utsname.h>
#include <linux/ctype.h>
#include <linux/uio.h>
#include <linux/sched/clock.h>
#include <linux/sched/debug.h>
#include <linux/sched/task_stack.h>
-#include <linux/kexec.h>

#include <linux/uaccess.h>
#include <asm/sections.h>
@@ -3257,62 +3255,4 @@ void kmsg_dump_rewind(struct kmsg_dumper
}
EXPORT_SYMBOL_GPL(kmsg_dump_rewind);

-static char dump_stack_arch_desc_str[128];
-
-/**
- * dump_stack_set_arch_desc - set arch-specific str to show with task dumps
- * @fmt: printf-style format string
- * @...: arguments for the format string
- *
- * The configured string will be printed right after utsname during task
- * dumps. Usually used to add arch-specific system identifiers. If an
- * arch wants to make use of such an ID string, it should initialize this
- * as soon as possible during boot.
- */
-void __init dump_stack_set_arch_desc(const char *fmt, ...)
-{
- va_list args;
-
- va_start(args, fmt);
- vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str),
- fmt, args);
- va_end(args);
-}
-
-/**
- * dump_stack_print_info - print generic debug info for dump_stack()
- * @log_lvl: log level
- *
- * Arch-specific dump_stack() implementations can use this function to
- * print out the same debug information as the generic dump_stack().
- */
-void dump_stack_print_info(const char *log_lvl)
-{
- printk("%sCPU: %d PID: %d Comm: %.20s %s%s %s %.*s\n",
- log_lvl, raw_smp_processor_id(), current->pid, current->comm,
- kexec_crash_loaded() ? "Kdump: loaded " : "",
- print_tainted(),
- init_utsname()->release,
- (int)strcspn(init_utsname()->version, " "),
- init_utsname()->version);
-
- if (dump_stack_arch_desc_str[0] != '\0')
- printk("%sHardware name: %s\n",
- log_lvl, dump_stack_arch_desc_str);
-
- print_worker_info(log_lvl, current);
-}
-
-/**
- * show_regs_print_info - print generic debug info for show_regs()
- * @log_lvl: log level
- *
- * show_regs() implementations can use this function to print out generic
- * debug information.
- */
-void show_regs_print_info(const char *log_lvl)
-{
- dump_stack_print_info(log_lvl);
-}
-
#endif
--- linux-x86.orig/lib/dump_stack.c
+++ linux-x86/lib/dump_stack.c
@@ -10,6 +10,66 @@
#include <linux/sched/debug.h>
#include <linux/smp.h>
#include <linux/atomic.h>
+#include <linux/kexec.h>
+#include <linux/utsname.h>
+
+static char dump_stack_arch_desc_str[128];
+
+/**
+ * dump_stack_set_arch_desc - set arch-specific str to show with task dumps
+ * @fmt: printf-style format string
+ * @...: arguments for the format string
+ *
+ * The configured string will be printed right after utsname during task
+ * dumps. Usually used to add arch-specific system identifiers. If an
+ * arch wants to make use of such an ID string, it should initialize this
+ * as soon as possible during boot.
+ */
+void __init dump_stack_set_arch_desc(const char *fmt, ...)
+{
+ va_list args;
+
+ va_start(args, fmt);
+ vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str),
+ fmt, args);
+ va_end(args);
+}
+
+/**
+ * dump_stack_print_info - print generic debug info for dump_stack()
+ * @log_lvl: log level
+ *
+ * Arch-specific dump_stack() implementations can use this function to
+ * print out the same debug information as the generic dump_stack().
+ */
+void dump_stack_print_info(const char *log_lvl)
+{
+ printk("%sCPU: %d PID: %d Comm: %.20s %s%s %s %.*s\n",
+ log_lvl, raw_smp_processor_id(), current->pid, current->comm,
+ kexec_crash_loaded() ? "Kdump: loaded " : "",
+ print_tainted(),
+ init_utsname()->release,
+ (int)strcspn(init_utsname()->version, " "),
+ init_utsname()->version);
+
+ if (dump_stack_arch_desc_str[0] != '\0')
+ printk("%sHardware name: %s\n",
+ log_lvl, dump_stack_arch_desc_str);
+
+ print_worker_info(log_lvl, current);
+}
+
+/**
+ * show_regs_print_info - print generic debug info for show_regs()
+ * @log_lvl: log level
+ *
+ * show_regs() implementations can use this function to print out generic
+ * debug information.
+ */
+void show_regs_print_info(const char *log_lvl)
+{
+ dump_stack_print_info(log_lvl);
+}

static void __dump_stack(void)
{
--- linux-x86.orig/include/linux/printk.h
+++ linux-x86/include/linux/printk.h
@@ -201,6 +201,7 @@ void __init setup_log_buf(int early);
__printf(1, 2) void dump_stack_set_arch_desc(const char *fmt, ...);
void dump_stack_print_info(const char *log_lvl);
void show_regs_print_info(const char *log_lvl);
+extern asmlinkage void dump_stack(void) __cold;
extern void printk_safe_init(void);
extern void printk_safe_flush(void);
extern void printk_safe_flush_on_panic(void);
@@ -264,6 +265,10 @@ static inline void show_regs_print_info(
{
}

+static inline asmlinkage void dump_stack(void)
+{
+}
+
static inline void printk_safe_init(void)
{
}
@@ -279,8 +284,6 @@ static inline void printk_safe_flush_on_

extern int kptr_restrict;

-extern asmlinkage void dump_stack(void) __cold;
-
#ifndef pr_fmt
#define pr_fmt(fmt) fmt
#endif
--- linux-x86.orig/lib/Makefile
+++ linux-x86/lib/Makefile
@@ -18,7 +18,7 @@ KCOV_INSTRUMENT_debugobjects.o := n
KCOV_INSTRUMENT_dynamic_debug.o := n

lib-y := ctype.o string.o vsprintf.o cmdline.o \
- rbtree.o radix-tree.o dump_stack.o timerqueue.o\
+ rbtree.o radix-tree.o timerqueue.o\
idr.o int_sqrt.o extable.o \
sha1.o chacha20.o irq_regs.o argv_split.o \
flex_proportions.o ratelimit.o show_mem.o \
@@ -26,6 +26,7 @@ lib-y := ctype.o string.o vsprintf.o cmd
earlycpio.o seq_buf.o siphash.o \
nmi_backtrace.o nodemask.o win_minmax.o

+lib-$(CONFIG_PRINTK) += dump_stack.o
lib-$(CONFIG_MMU) += ioremap.o
lib-$(CONFIG_SMP) += cpumask.o
lib-$(CONFIG_DMA_DIRECT_OPS) += dma-direct.o