xref: /openbmc/linux/lib/dump_stack.c (revision f5c27da4)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Provide a default dump_stack() function for architectures
4  * which don't implement their own.
5  */
6 
7 #include <linux/kernel.h>
8 #include <linux/buildid.h>
9 #include <linux/export.h>
10 #include <linux/sched.h>
11 #include <linux/sched/debug.h>
12 #include <linux/smp.h>
13 #include <linux/atomic.h>
14 #include <linux/kexec.h>
15 #include <linux/utsname.h>
16 #include <linux/stop_machine.h>
17 
18 static char dump_stack_arch_desc_str[128];
19 
20 /**
21  * dump_stack_set_arch_desc - set arch-specific str to show with task dumps
22  * @fmt: printf-style format string
23  * @...: arguments for the format string
24  *
25  * The configured string will be printed right after utsname during task
26  * dumps.  Usually used to add arch-specific system identifiers.  If an
27  * arch wants to make use of such an ID string, it should initialize this
28  * as soon as possible during boot.
29  */
30 void __init dump_stack_set_arch_desc(const char *fmt, ...)
31 {
32 	va_list args;
33 
34 	va_start(args, fmt);
35 	vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str),
36 		  fmt, args);
37 	va_end(args);
38 }
39 
40 #if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
41 #define BUILD_ID_FMT " %20phN"
42 #define BUILD_ID_VAL vmlinux_build_id
43 #else
44 #define BUILD_ID_FMT "%s"
45 #define BUILD_ID_VAL ""
46 #endif
47 
48 /**
49  * dump_stack_print_info - print generic debug info for dump_stack()
50  * @log_lvl: log level
51  *
52  * Arch-specific dump_stack() implementations can use this function to
53  * print out the same debug information as the generic dump_stack().
54  */
55 void dump_stack_print_info(const char *log_lvl)
56 {
57 	printk("%sCPU: %d PID: %d Comm: %.20s %s%s %s %.*s" BUILD_ID_FMT "\n",
58 	       log_lvl, raw_smp_processor_id(), current->pid, current->comm,
59 	       kexec_crash_loaded() ? "Kdump: loaded " : "",
60 	       print_tainted(),
61 	       init_utsname()->release,
62 	       (int)strcspn(init_utsname()->version, " "),
63 	       init_utsname()->version, BUILD_ID_VAL);
64 
65 	if (dump_stack_arch_desc_str[0] != '\0')
66 		printk("%sHardware name: %s\n",
67 		       log_lvl, dump_stack_arch_desc_str);
68 
69 	print_worker_info(log_lvl, current);
70 	print_stop_info(log_lvl, current);
71 }
72 
73 /**
74  * show_regs_print_info - print generic debug info for show_regs()
75  * @log_lvl: log level
76  *
77  * show_regs() implementations can use this function to print out generic
78  * debug information.
79  */
80 void show_regs_print_info(const char *log_lvl)
81 {
82 	dump_stack_print_info(log_lvl);
83 }
84 
85 static void __dump_stack(const char *log_lvl)
86 {
87 	dump_stack_print_info(log_lvl);
88 	show_stack(NULL, NULL, log_lvl);
89 }
90 
91 /**
92  * dump_stack_lvl - dump the current task information and its stack trace
93  * @log_lvl: log level
94  *
95  * Architectures can override this implementation by implementing its own.
96  */
97 asmlinkage __visible void dump_stack_lvl(const char *log_lvl)
98 {
99 	unsigned long flags;
100 
101 	/*
102 	 * Permit this cpu to perform nested stack dumps while serialising
103 	 * against other CPUs
104 	 */
105 	printk_cpu_sync_get_irqsave(flags);
106 	__dump_stack(log_lvl);
107 	printk_cpu_sync_put_irqrestore(flags);
108 }
109 EXPORT_SYMBOL(dump_stack_lvl);
110 
111 asmlinkage __visible void dump_stack(void)
112 {
113 	dump_stack_lvl(KERN_DEFAULT);
114 }
115 EXPORT_SYMBOL(dump_stack);
116