mirror of
https://github.com/torvalds/linux.git
synced 2024-11-12 15:11:50 +00:00
ccd0d44fad
The define to use ({0;}) for the !CONFIG_SMP case of WARN_ON_SMP()
can be confusing. As the WARN_ON_SMP() needs to be a nop when
CONFIG_SMP is not set, including all its parameters must not be
evaluated, and that it must work as both a stand alone statement
and inside an if condition, we define it to a funky ({0;}).
A simple "0" will not work as it causes gcc to give the warning that
the statement has no effect.
As this strange definition has raised a few eyebrows from some
major kernel developers, it is wise to document why we create such
a work of art.
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
208 lines
5.5 KiB
C
208 lines
5.5 KiB
C
#ifndef _ASM_GENERIC_BUG_H
|
|
#define _ASM_GENERIC_BUG_H
|
|
|
|
#include <linux/compiler.h>
|
|
|
|
#ifdef CONFIG_BUG
|
|
|
|
#ifdef CONFIG_GENERIC_BUG
|
|
#ifndef __ASSEMBLY__
|
|
struct bug_entry {
|
|
#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
|
|
unsigned long bug_addr;
|
|
#else
|
|
signed int bug_addr_disp;
|
|
#endif
|
|
#ifdef CONFIG_DEBUG_BUGVERBOSE
|
|
#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
|
|
const char *file;
|
|
#else
|
|
signed int file_disp;
|
|
#endif
|
|
unsigned short line;
|
|
#endif
|
|
unsigned short flags;
|
|
};
|
|
#endif /* __ASSEMBLY__ */
|
|
|
|
#define BUGFLAG_WARNING (1 << 0)
|
|
#define BUGFLAG_TAINT(taint) (BUGFLAG_WARNING | ((taint) << 8))
|
|
#define BUG_GET_TAINT(bug) ((bug)->flags >> 8)
|
|
|
|
#endif /* CONFIG_GENERIC_BUG */
|
|
|
|
/*
|
|
* Don't use BUG() or BUG_ON() unless there's really no way out; one
|
|
* example might be detecting data structure corruption in the middle
|
|
* of an operation that can't be backed out of. If the (sub)system
|
|
* can somehow continue operating, perhaps with reduced functionality,
|
|
* it's probably not BUG-worthy.
|
|
*
|
|
* If you're tempted to BUG(), think again: is completely giving up
|
|
* really the *only* solution? There are usually better options, where
|
|
* users don't need to reboot ASAP and can mostly shut down cleanly.
|
|
*/
|
|
#ifndef HAVE_ARCH_BUG
|
|
#define BUG() do { \
|
|
printk("BUG: failure at %s:%d/%s()!\n", __FILE__, __LINE__, __func__); \
|
|
panic("BUG!"); \
|
|
} while (0)
|
|
#endif
|
|
|
|
#ifndef HAVE_ARCH_BUG_ON
|
|
#define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while(0)
|
|
#endif
|
|
|
|
/*
|
|
* WARN(), WARN_ON(), WARN_ON_ONCE, and so on can be used to report
|
|
* significant issues that need prompt attention if they should ever
|
|
* appear at runtime. Use the versions with printk format strings
|
|
* to provide better diagnostics.
|
|
*/
|
|
#ifndef __WARN_TAINT
|
|
#ifndef __ASSEMBLY__
|
|
extern void warn_slowpath_fmt(const char *file, const int line,
|
|
const char *fmt, ...) __attribute__((format(printf, 3, 4)));
|
|
extern void warn_slowpath_fmt_taint(const char *file, const int line,
|
|
unsigned taint, const char *fmt, ...)
|
|
__attribute__((format(printf, 4, 5)));
|
|
extern void warn_slowpath_null(const char *file, const int line);
|
|
#define WANT_WARN_ON_SLOWPATH
|
|
#endif
|
|
#define __WARN() warn_slowpath_null(__FILE__, __LINE__)
|
|
#define __WARN_printf(arg...) warn_slowpath_fmt(__FILE__, __LINE__, arg)
|
|
#define __WARN_printf_taint(taint, arg...) \
|
|
warn_slowpath_fmt_taint(__FILE__, __LINE__, taint, arg)
|
|
#else
|
|
#define __WARN() __WARN_TAINT(TAINT_WARN)
|
|
#define __WARN_printf(arg...) do { printk(arg); __WARN(); } while (0)
|
|
#define __WARN_printf_taint(taint, arg...) \
|
|
do { printk(arg); __WARN_TAINT(taint); } while (0)
|
|
#endif
|
|
|
|
#ifndef WARN_ON
|
|
#define WARN_ON(condition) ({ \
|
|
int __ret_warn_on = !!(condition); \
|
|
if (unlikely(__ret_warn_on)) \
|
|
__WARN(); \
|
|
unlikely(__ret_warn_on); \
|
|
})
|
|
#endif
|
|
|
|
#ifndef WARN
|
|
#define WARN(condition, format...) ({ \
|
|
int __ret_warn_on = !!(condition); \
|
|
if (unlikely(__ret_warn_on)) \
|
|
__WARN_printf(format); \
|
|
unlikely(__ret_warn_on); \
|
|
})
|
|
#endif
|
|
|
|
#define WARN_TAINT(condition, taint, format...) ({ \
|
|
int __ret_warn_on = !!(condition); \
|
|
if (unlikely(__ret_warn_on)) \
|
|
__WARN_printf_taint(taint, format); \
|
|
unlikely(__ret_warn_on); \
|
|
})
|
|
|
|
#else /* !CONFIG_BUG */
|
|
#ifndef HAVE_ARCH_BUG
|
|
#define BUG() do {} while(0)
|
|
#endif
|
|
|
|
#ifndef HAVE_ARCH_BUG_ON
|
|
#define BUG_ON(condition) do { if (condition) ; } while(0)
|
|
#endif
|
|
|
|
#ifndef HAVE_ARCH_WARN_ON
|
|
#define WARN_ON(condition) ({ \
|
|
int __ret_warn_on = !!(condition); \
|
|
unlikely(__ret_warn_on); \
|
|
})
|
|
#endif
|
|
|
|
#ifndef WARN
|
|
#define WARN(condition, format...) ({ \
|
|
int __ret_warn_on = !!(condition); \
|
|
unlikely(__ret_warn_on); \
|
|
})
|
|
#endif
|
|
|
|
#define WARN_TAINT(condition, taint, format...) WARN_ON(condition)
|
|
|
|
#endif
|
|
|
|
#define WARN_ON_ONCE(condition) ({ \
|
|
static bool __warned; \
|
|
int __ret_warn_once = !!(condition); \
|
|
\
|
|
if (unlikely(__ret_warn_once)) \
|
|
if (WARN_ON(!__warned)) \
|
|
__warned = true; \
|
|
unlikely(__ret_warn_once); \
|
|
})
|
|
|
|
#define WARN_ONCE(condition, format...) ({ \
|
|
static bool __warned; \
|
|
int __ret_warn_once = !!(condition); \
|
|
\
|
|
if (unlikely(__ret_warn_once)) \
|
|
if (WARN(!__warned, format)) \
|
|
__warned = true; \
|
|
unlikely(__ret_warn_once); \
|
|
})
|
|
|
|
#define WARN_TAINT_ONCE(condition, taint, format...) ({ \
|
|
static bool __warned; \
|
|
int __ret_warn_once = !!(condition); \
|
|
\
|
|
if (unlikely(__ret_warn_once)) \
|
|
if (WARN_TAINT(!__warned, taint, format)) \
|
|
__warned = true; \
|
|
unlikely(__ret_warn_once); \
|
|
})
|
|
|
|
#define WARN_ON_RATELIMIT(condition, state) \
|
|
WARN_ON((condition) && __ratelimit(state))
|
|
|
|
/*
|
|
* WARN_ON_SMP() is for cases that the warning is either
|
|
* meaningless for !SMP or may even cause failures.
|
|
* This is usually used for cases that we have
|
|
* WARN_ON(!spin_is_locked(&lock)) checks, as spin_is_locked()
|
|
* returns 0 for uniprocessor settings.
|
|
* It can also be used with values that are only defined
|
|
* on SMP:
|
|
*
|
|
* struct foo {
|
|
* [...]
|
|
* #ifdef CONFIG_SMP
|
|
* int bar;
|
|
* #endif
|
|
* };
|
|
*
|
|
* void func(struct foo *zoot)
|
|
* {
|
|
* WARN_ON_SMP(!zoot->bar);
|
|
*
|
|
* For CONFIG_SMP, WARN_ON_SMP() should act the same as WARN_ON(),
|
|
* and should be a nop and return false for uniprocessor.
|
|
*
|
|
* if (WARN_ON_SMP(x)) returns true only when CONFIG_SMP is set
|
|
* and x is true.
|
|
*/
|
|
#ifdef CONFIG_SMP
|
|
# define WARN_ON_SMP(x) WARN_ON(x)
|
|
#else
|
|
/*
|
|
* Use of ({0;}) because WARN_ON_SMP(x) may be used either as
|
|
* a stand alone line statement or as a condition in an if ()
|
|
* statement.
|
|
* A simple "0" would cause gcc to give a "statement has no effect"
|
|
* warning.
|
|
*/
|
|
# define WARN_ON_SMP(x) ({0;})
|
|
#endif
|
|
|
|
#endif
|