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
8#define CUT_HERE		"------------[ cut here ]------------\n"
9
10#ifdef CONFIG_GENERIC_BUG
11#define BUGFLAG_WARNING		(1 << 0)
12#define BUGFLAG_ONCE		(1 << 1)
13#define BUGFLAG_DONE		(1 << 2)
14#define BUGFLAG_NO_CUT_HERE	(1 << 3)	/* CUT_HERE already sent */
15#define BUGFLAG_TAINT(taint)	((taint) << 8)
16#define BUG_GET_TAINT(bug)	((bug)->flags >> 8)
17#endif
18
19#ifndef __ASSEMBLY__
20#include <linux/kernel.h>
21
22#ifdef CONFIG_BUG
23
24#ifdef CONFIG_GENERIC_BUG
25struct bug_entry {
26#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
27	unsigned long	bug_addr;
28#else
29	signed int	bug_addr_disp;
30#endif
31#ifdef CONFIG_DEBUG_BUGVERBOSE
32#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
33	const char	*file;
34#else
35	signed int	file_disp;
36#endif
37	unsigned short	line;
38#endif
39	unsigned short	flags;
40};
41#endif	/* CONFIG_GENERIC_BUG */
42
43/*
44 * Don't use BUG() or BUG_ON() unless there's really no way out; one
45 * example might be detecting data structure corruption in the middle
46 * of an operation that can't be backed out of.  If the (sub)system
47 * can somehow continue operating, perhaps with reduced functionality,
48 * it's probably not BUG-worthy.
49 *
50 * If you're tempted to BUG(), think again:  is completely giving up
51 * really the *only* solution?  There are usually better options, where
52 * users don't need to reboot ASAP and can mostly shut down cleanly.
53 */
54#ifndef HAVE_ARCH_BUG
55#define BUG() do { \
56	printk("BUG: failure at %s:%d/%s()!\n", __FILE__, __LINE__, __func__); \
57	barrier_before_unreachable(); \
58	panic("BUG!"); \
59} while (0)
60#endif
61
62#ifndef HAVE_ARCH_BUG_ON
63#define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0)
64#endif
65
66/*
67 * WARN(), WARN_ON(), WARN_ON_ONCE, and so on can be used to report
68 * significant kernel issues that need prompt attention if they should ever
69 * appear at runtime.
70 *
71 * Do not use these macros when checking for invalid external inputs
72 * (e.g. invalid system call arguments, or invalid data coming from
73 * network/devices), and on transient conditions like ENOMEM or EAGAIN.
74 * These macros should be used for recoverable kernel issues only.
75 * For invalid external inputs, transient conditions, etc use
76 * pr_err[_once/_ratelimited]() followed by dump_stack(), if necessary.
77 * Do not include "BUG"/"WARNING" in format strings manually to make these
78 * conditions distinguishable from kernel issues.
79 *
80 * Use the versions with printk format strings to provide better diagnostics.
81 */
82#ifndef __WARN_FLAGS
83extern __printf(4, 5)
84void warn_slowpath_fmt(const char *file, const int line, unsigned taint,
85		       const char *fmt, ...);
86#define __WARN()		__WARN_printf(TAINT_WARN, NULL)
87#define __WARN_printf(taint, arg...) do {				\
88		instrumentation_begin();				\
89		warn_slowpath_fmt(__FILE__, __LINE__, taint, arg);	\
90		instrumentation_end();					\
91	} while (0)
92#else
93extern __printf(1, 2) void __warn_printk(const char *fmt, ...);
94#define __WARN()		__WARN_FLAGS(BUGFLAG_TAINT(TAINT_WARN))
95#define __WARN_printf(taint, arg...) do {				\
96		instrumentation_begin();				\
97		__warn_printk(arg);					\
98		__WARN_FLAGS(BUGFLAG_NO_CUT_HERE | BUGFLAG_TAINT(taint));\
99		instrumentation_end();					\
100	} while (0)
101#define WARN_ON_ONCE(condition) ({				\
102	int __ret_warn_on = !!(condition);			\
103	if (unlikely(__ret_warn_on))				\
104		__WARN_FLAGS(BUGFLAG_ONCE |			\
105			     BUGFLAG_TAINT(TAINT_WARN));	\
106	unlikely(__ret_warn_on);				\
107})
108#endif
109
110/* used internally by panic.c */
111struct warn_args;
112struct pt_regs;
113
114void __warn(const char *file, int line, void *caller, unsigned taint,
115	    struct pt_regs *regs, struct warn_args *args);
116
117#ifndef WARN_ON
118#define WARN_ON(condition) ({						\
119	int __ret_warn_on = !!(condition);				\
120	if (unlikely(__ret_warn_on))					\
121		__WARN();						\
122	unlikely(__ret_warn_on);					\
123})
124#endif
125
126#ifndef WARN
127#define WARN(condition, format...) ({					\
128	int __ret_warn_on = !!(condition);				\
129	if (unlikely(__ret_warn_on))					\
130		__WARN_printf(TAINT_WARN, format);			\
131	unlikely(__ret_warn_on);					\
132})
133#endif
134
135#define WARN_TAINT(condition, taint, format...) ({			\
136	int __ret_warn_on = !!(condition);				\
137	if (unlikely(__ret_warn_on))					\
138		__WARN_printf(taint, format);				\
139	unlikely(__ret_warn_on);					\
140})
141
142#ifndef WARN_ON_ONCE
143#define WARN_ON_ONCE(condition)	({				\
144	static bool __section(".data.once") __warned;		\
145	int __ret_warn_once = !!(condition);			\
146								\
147	if (unlikely(__ret_warn_once && !__warned)) {		\
148		__warned = true;				\
149		WARN_ON(1);					\
150	}							\
151	unlikely(__ret_warn_once);				\
152})
153#endif
154
155#define WARN_ONCE(condition, format...)	({			\
156	static bool __section(".data.once") __warned;		\
157	int __ret_warn_once = !!(condition);			\
158								\
159	if (unlikely(__ret_warn_once && !__warned)) {		\
160		__warned = true;				\
161		WARN(1, format);				\
162	}							\
163	unlikely(__ret_warn_once);				\
164})
165
166#define WARN_TAINT_ONCE(condition, taint, format...)	({	\
167	static bool __section(".data.once") __warned;		\
168	int __ret_warn_once = !!(condition);			\
169								\
170	if (unlikely(__ret_warn_once && !__warned)) {		\
171		__warned = true;				\
172		WARN_TAINT(1, taint, format);			\
173	}							\
174	unlikely(__ret_warn_once);				\
175})
176
177#else /* !CONFIG_BUG */
178#ifndef HAVE_ARCH_BUG
179#define BUG() do {} while (1)
180#endif
181
182#ifndef HAVE_ARCH_BUG_ON
183#define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0)
184#endif
185
186#ifndef HAVE_ARCH_WARN_ON
187#define WARN_ON(condition) ({						\
188	int __ret_warn_on = !!(condition);				\
189	unlikely(__ret_warn_on);					\
190})
191#endif
192
193#ifndef WARN
194#define WARN(condition, format...) ({					\
195	int __ret_warn_on = !!(condition);				\
196	no_printk(format);						\
197	unlikely(__ret_warn_on);					\
198})
199#endif
200
201#define WARN_ON_ONCE(condition) WARN_ON(condition)
202#define WARN_ONCE(condition, format...) WARN(condition, format)
203#define WARN_TAINT(condition, taint, format...) WARN(condition, format)
204#define WARN_TAINT_ONCE(condition, taint, format...) WARN(condition, format)
205
206#endif
207
208/*
209 * WARN_ON_SMP() is for cases that the warning is either
210 * meaningless for !SMP or may even cause failures.
211 * It can also be used with values that are only defined
212 * on SMP:
213 *
214 * struct foo {
215 *  [...]
216 * #ifdef CONFIG_SMP
217 *	int bar;
218 * #endif
219 * };
220 *
221 * void func(struct foo *zoot)
222 * {
223 *	WARN_ON_SMP(!zoot->bar);
224 *
225 * For CONFIG_SMP, WARN_ON_SMP() should act the same as WARN_ON(),
226 * and should be a nop and return false for uniprocessor.
227 *
228 * if (WARN_ON_SMP(x)) returns true only when CONFIG_SMP is set
229 * and x is true.
230 */
231#ifdef CONFIG_SMP
232# define WARN_ON_SMP(x)			WARN_ON(x)
233#else
234/*
235 * Use of ({0;}) because WARN_ON_SMP(x) may be used either as
236 * a stand alone line statement or as a condition in an if ()
237 * statement.
238 * A simple "0" would cause gcc to give a "statement has no effect"
239 * warning.
240 */
241# define WARN_ON_SMP(x)			({0;})
242#endif
243
244/*
245 * WARN_ON_FUNCTION_MISMATCH() warns if a value doesn't match a
246 * function address, and can be useful for catching issues with
247 * callback functions, for example.
248 *
249 * With CONFIG_CFI_CLANG, the warning is disabled because the
250 * compiler replaces function addresses taken in C code with
251 * local jump table addresses, which breaks cross-module function
252 * address equality.
253 */
254#if defined(CONFIG_CFI_CLANG) && defined(CONFIG_MODULES)
255# define WARN_ON_FUNCTION_MISMATCH(x, fn) ({ 0; })
256#else
257# define WARN_ON_FUNCTION_MISMATCH(x, fn) WARN_ON_ONCE((x) != (fn))
258#endif
259
260#endif /* __ASSEMBLY__ */
261
262#endif
263