linux_dsm_epyc7002/include/linux/bug.h
Peter Zijlstra 19d436268d debug: Add _ONCE() logic to report_bug()
Josh suggested moving the _ONCE logic inside the trap handler, using a
bit in the bug_entry::flags field, avoiding the need for the extra
variable.

Sadly this only works for WARN_ON_ONCE(), since the others have
printk() statements prior to triggering the trap.

Still, this saves a fair amount of text and some data:

  text         data       filename
  10682460     4530992    defconfig-build/vmlinux.orig
  10665111     4530096    defconfig-build/vmlinux.patched

Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-30 09:37:20 +02:00

144 lines
4.5 KiB
C

#ifndef _LINUX_BUG_H
#define _LINUX_BUG_H
#include <asm/bug.h>
#include <linux/compiler.h>
enum bug_trap_type {
BUG_TRAP_TYPE_NONE = 0,
BUG_TRAP_TYPE_WARN = 1,
BUG_TRAP_TYPE_BUG = 2,
};
struct pt_regs;
#ifdef __CHECKER__
#define __BUILD_BUG_ON_NOT_POWER_OF_2(n) (0)
#define BUILD_BUG_ON_NOT_POWER_OF_2(n) (0)
#define BUILD_BUG_ON_ZERO(e) (0)
#define BUILD_BUG_ON_NULL(e) ((void*)0)
#define BUILD_BUG_ON_INVALID(e) (0)
#define BUILD_BUG_ON_MSG(cond, msg) (0)
#define BUILD_BUG_ON(condition) (0)
#define BUILD_BUG() (0)
#define MAYBE_BUILD_BUG_ON(cond) (0)
#else /* __CHECKER__ */
/* Force a compilation error if a constant expression is not a power of 2 */
#define __BUILD_BUG_ON_NOT_POWER_OF_2(n) \
BUILD_BUG_ON(((n) & ((n) - 1)) != 0)
#define BUILD_BUG_ON_NOT_POWER_OF_2(n) \
BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0))
/* Force a compilation error if condition is true, but also produce a
result (of value 0 and type size_t), so the expression can be used
e.g. in a structure initializer (or where-ever else comma expressions
aren't permitted). */
#define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))
#define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))
/*
* BUILD_BUG_ON_INVALID() permits the compiler to check the validity of the
* expression but avoids the generation of any code, even if that expression
* has side-effects.
*/
#define BUILD_BUG_ON_INVALID(e) ((void)(sizeof((__force long)(e))))
/**
* BUILD_BUG_ON_MSG - break compile if a condition is true & emit supplied
* error message.
* @condition: the condition which the compiler should know is false.
*
* See BUILD_BUG_ON for description.
*/
#define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
/**
* BUILD_BUG_ON - break compile if a condition is true.
* @condition: the condition which the compiler should know is false.
*
* If you have some code which relies on certain constants being equal, or
* some other compile-time-evaluated condition, you should use BUILD_BUG_ON to
* detect if someone changes it.
*
* The implementation uses gcc's reluctance to create a negative array, but gcc
* (as of 4.4) only emits that error for obvious cases (e.g. not arguments to
* inline functions). Luckily, in 4.3 they added the "error" function
* attribute just for this type of case. Thus, we use a negative sized array
* (should always create an error on gcc versions older than 4.4) and then call
* an undefined function with the error attribute (should always create an
* error on gcc 4.3 and later). If for some reason, neither creates a
* compile-time error, we'll still have a link-time error, which is harder to
* track down.
*/
#ifndef __OPTIMIZE__
#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
#else
#define BUILD_BUG_ON(condition) \
BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
#endif
/**
* BUILD_BUG - break compile if used.
*
* If you have some code that you expect the compiler to eliminate at
* build time, you should use BUILD_BUG to detect if it is
* unexpectedly used.
*/
#define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed")
#define MAYBE_BUILD_BUG_ON(cond) \
do { \
if (__builtin_constant_p((cond))) \
BUILD_BUG_ON(cond); \
else \
BUG_ON(cond); \
} while (0)
#endif /* __CHECKER__ */
#ifdef CONFIG_GENERIC_BUG
#include <asm-generic/bug.h>
static inline int is_warning_bug(const struct bug_entry *bug)
{
return bug->flags & BUGFLAG_WARNING;
}
struct bug_entry *find_bug(unsigned long bugaddr);
enum bug_trap_type report_bug(unsigned long bug_addr, struct pt_regs *regs);
/* These are defined by the architecture */
int is_valid_bugaddr(unsigned long addr);
#else /* !CONFIG_GENERIC_BUG */
static inline enum bug_trap_type report_bug(unsigned long bug_addr,
struct pt_regs *regs)
{
return BUG_TRAP_TYPE_BUG;
}
#endif /* CONFIG_GENERIC_BUG */
/*
* Since detected data corruption should stop operation on the affected
* structures. Return value must be checked and sanely acted on by caller.
*/
static inline __must_check bool check_data_corruption(bool v) { return v; }
#define CHECK_DATA_CORRUPTION(condition, fmt, ...) \
check_data_corruption(({ \
bool corruption = unlikely(condition); \
if (corruption) { \
if (IS_ENABLED(CONFIG_BUG_ON_DATA_CORRUPTION)) { \
pr_err(fmt, ##__VA_ARGS__); \
BUG(); \
} else \
WARN(1, fmt, ##__VA_ARGS__); \
} \
corruption; \
}))
#endif /* _LINUX_BUG_H */