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
24struct warn_args;
25struct pt_regs;
26
27void __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
33struct 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
91extern __printf(4, 5)
92void 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
101extern __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/*
224 * WARN_ON_FUNCTION_MISMATCH() warns if a value doesn't match a
225 * function address, and can be useful for catching issues with
226 * callback functions, for example.
227 *
228 * With CONFIG_CFI_CLANG, the warning is disabled because the
229 * compiler replaces function addresses taken in C code with
230 * local jump table addresses, which breaks cross-module function
231 * address equality.
232 */
233#if defined(CONFIG_CFI_CLANG) && defined(CONFIG_MODULES)
234# define WARN_ON_FUNCTION_MISMATCH(x, fn) ({ 0; })
235#else
236# define WARN_ON_FUNCTION_MISMATCH(x, fn) WARN_ON_ONCE((x) != (fn))
237#endif
238
239#endif /* __ASSEMBLY__ */
240
241#endif
242