1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_GENERIC_BUG_H
3 #define _ASM_GENERIC_BUG_H
4 
5 #include <linux/compiler.h>
6 #include <linux/instrumentation.h>
7 #include <linux/once_lite.h>
8 
9 #define CUT_HERE		"------------[ cut here ]------------\n"
10 
11 #ifdef CONFIG_GENERIC_BUG
12 #define BUGFLAG_WARNING		(1 << 0)
13 #define BUGFLAG_ONCE		(1 << 1)
14 #define BUGFLAG_DONE		(1 << 2)
15 #define BUGFLAG_NO_CUT_HERE	(1 << 3)	/* CUT_HERE already sent */
16 #define BUGFLAG_TAINT(taint)	((taint) << 8)
17 #define BUG_GET_TAINT(bug)	((bug)->flags >> 8)
18 #endif
19 
20 #ifndef __ASSEMBLY__
21 #include <linux/panic.h>
22 #include <linux/printk.h>
23 
24 struct warn_args;
25 struct pt_regs;
26 
27 void __warn(const char *file, int line, void *caller, unsigned taint,
28 	    struct pt_regs *regs, struct warn_args *args);
29 
30 #ifdef CONFIG_BUG
31 
32 #ifdef CONFIG_GENERIC_BUG
33 struct bug_entry {
34 #ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
35 	unsigned long	bug_addr;
36 #else
37 	signed int	bug_addr_disp;
38 #endif
39 #ifdef CONFIG_DEBUG_BUGVERBOSE
40 #ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
41 	const char	*file;
42 #else
43 	signed int	file_disp;
44 #endif
45 	unsigned short	line;
46 #endif
47 	unsigned short	flags;
48 };
49 #endif	/* CONFIG_GENERIC_BUG */
50 
51 /*
52  * Don't use BUG() or BUG_ON() unless there's really no way out; one
53  * example might be detecting data structure corruption in the middle
54  * of an operation that can't be backed out of.  If the (sub)system
55  * can somehow continue operating, perhaps with reduced functionality,
56  * it's probably not BUG-worthy.
57  *
58  * If you're tempted to BUG(), think again:  is completely giving up
59  * really the *only* solution?  There are usually better options, where
60  * users don't need to reboot ASAP and can mostly shut down cleanly.
61  */
62 #ifndef HAVE_ARCH_BUG
63 #define BUG() do { \
64 	printk("BUG: failure at %s:%d/%s()!\n", __FILE__, __LINE__, __func__); \
65 	barrier_before_unreachable(); \
66 	panic("BUG!"); \
67 } while (0)
68 #endif
69 
70 #ifndef HAVE_ARCH_BUG_ON
71 #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0)
72 #endif
73 
74 /*
75  * WARN(), WARN_ON(), WARN_ON_ONCE, and so on can be used to report
76  * significant kernel issues that need prompt attention if they should ever
77  * appear at runtime.
78  *
79  * Do not use these macros when checking for invalid external inputs
80  * (e.g. invalid system call arguments, or invalid data coming from
81  * network/devices), and on transient conditions like ENOMEM or EAGAIN.
82  * These macros should be used for recoverable kernel issues only.
83  * For invalid external inputs, transient conditions, etc use
84  * pr_err[_once/_ratelimited]() followed by dump_stack(), if necessary.
85  * Do not include "BUG"/"WARNING" in format strings manually to make these
86  * conditions distinguishable from kernel issues.
87  *
88  * Use the versions with printk format strings to provide better diagnostics.
89  */
90 #ifndef __WARN_FLAGS
91 extern __printf(4, 5)
92 void warn_slowpath_fmt(const char *file, const int line, unsigned taint,
93 		       const char *fmt, ...);
94 #define __WARN()		__WARN_printf(TAINT_WARN, NULL)
95 #define __WARN_printf(taint, arg...) do {				\
96 		instrumentation_begin();				\
97 		warn_slowpath_fmt(__FILE__, __LINE__, taint, arg);	\
98 		instrumentation_end();					\
99 	} while (0)
100 #else
101 extern __printf(1, 2) void __warn_printk(const char *fmt, ...);
102 #define __WARN()		__WARN_FLAGS(BUGFLAG_TAINT(TAINT_WARN))
103 #define __WARN_printf(taint, arg...) do {				\
104 		instrumentation_begin();				\
105 		__warn_printk(arg);					\
106 		__WARN_FLAGS(BUGFLAG_NO_CUT_HERE | BUGFLAG_TAINT(taint));\
107 		instrumentation_end();					\
108 	} while (0)
109 #define WARN_ON_ONCE(condition) ({				\
110 	int __ret_warn_on = !!(condition);			\
111 	if (unlikely(__ret_warn_on))				\
112 		__WARN_FLAGS(BUGFLAG_ONCE |			\
113 			     BUGFLAG_TAINT(TAINT_WARN));	\
114 	unlikely(__ret_warn_on);				\
115 })
116 #endif
117 
118 /* used internally by panic.c */
119 
120 #ifndef WARN_ON
121 #define WARN_ON(condition) ({						\
122 	int __ret_warn_on = !!(condition);				\
123 	if (unlikely(__ret_warn_on))					\
124 		__WARN();						\
125 	unlikely(__ret_warn_on);					\
126 })
127 #endif
128 
129 #ifndef WARN
130 #define WARN(condition, format...) ({					\
131 	int __ret_warn_on = !!(condition);				\
132 	if (unlikely(__ret_warn_on))					\
133 		__WARN_printf(TAINT_WARN, format);			\
134 	unlikely(__ret_warn_on);					\
135 })
136 #endif
137 
138 #define WARN_TAINT(condition, taint, format...) ({			\
139 	int __ret_warn_on = !!(condition);				\
140 	if (unlikely(__ret_warn_on))					\
141 		__WARN_printf(taint, format);				\
142 	unlikely(__ret_warn_on);					\
143 })
144 
145 #ifndef WARN_ON_ONCE
146 #define WARN_ON_ONCE(condition)					\
147 	DO_ONCE_LITE_IF(condition, WARN_ON, 1)
148 #endif
149 
150 #define WARN_ONCE(condition, format...)				\
151 	DO_ONCE_LITE_IF(condition, WARN, 1, format)
152 
153 #define WARN_TAINT_ONCE(condition, taint, format...)		\
154 	DO_ONCE_LITE_IF(condition, WARN_TAINT, 1, taint, format)
155 
156 #else /* !CONFIG_BUG */
157 #ifndef HAVE_ARCH_BUG
158 #define BUG() do {} while (1)
159 #endif
160 
161 #ifndef HAVE_ARCH_BUG_ON
162 #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0)
163 #endif
164 
165 #ifndef HAVE_ARCH_WARN_ON
166 #define WARN_ON(condition) ({						\
167 	int __ret_warn_on = !!(condition);				\
168 	unlikely(__ret_warn_on);					\
169 })
170 #endif
171 
172 #ifndef WARN
173 #define WARN(condition, format...) ({					\
174 	int __ret_warn_on = !!(condition);				\
175 	no_printk(format);						\
176 	unlikely(__ret_warn_on);					\
177 })
178 #endif
179 
180 #define WARN_ON_ONCE(condition) WARN_ON(condition)
181 #define WARN_ONCE(condition, format...) WARN(condition, format)
182 #define WARN_TAINT(condition, taint, format...) WARN(condition, format)
183 #define WARN_TAINT_ONCE(condition, taint, format...) WARN(condition, format)
184 
185 #endif
186 
187 /*
188  * WARN_ON_SMP() is for cases that the warning is either
189  * meaningless for !SMP or may even cause failures.
190  * It can also be used with values that are only defined
191  * on SMP:
192  *
193  * struct foo {
194  *  [...]
195  * #ifdef CONFIG_SMP
196  *	int bar;
197  * #endif
198  * };
199  *
200  * void func(struct foo *zoot)
201  * {
202  *	WARN_ON_SMP(!zoot->bar);
203  *
204  * For CONFIG_SMP, WARN_ON_SMP() should act the same as WARN_ON(),
205  * and should be a nop and return false for uniprocessor.
206  *
207  * if (WARN_ON_SMP(x)) returns true only when CONFIG_SMP is set
208  * and x is true.
209  */
210 #ifdef CONFIG_SMP
211 # define WARN_ON_SMP(x)			WARN_ON(x)
212 #else
213 /*
214  * Use of ({0;}) because WARN_ON_SMP(x) may be used either as
215  * a stand alone line statement or as a condition in an if ()
216  * statement.
217  * A simple "0" would cause gcc to give a "statement has no effect"
218  * warning.
219  */
220 # define WARN_ON_SMP(x)			({0;})
221 #endif
222 
223 #endif /* __ASSEMBLY__ */
224 
225 #endif
226