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linux/include/asm-powerpc/bug.h
Michael Ellerman e3f94b85f9 [PATCH] powerpc: Make BUG_ON & WARN_ON play nice with compile-time optimisations
Change BUG_ON and WARN_ON to give the compiler a chance to perform
compile-time optimsations. Depending on the complexity of the condition,
the compiler may not do this very well, so if it's important check the
object code.

Current GCC's (4.x) produce good code as long as the condition does not
include a function call, including a static inline.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-03-27 14:48:10 +11:00

99 lines
2.4 KiB
C

#ifndef _ASM_POWERPC_BUG_H
#define _ASM_POWERPC_BUG_H
#ifdef __KERNEL__
#include <asm/asm-compat.h>
/*
* Define an illegal instr to trap on the bug.
* We don't use 0 because that marks the end of a function
* in the ELF ABI. That's "Boo Boo" in case you wonder...
*/
#define BUG_OPCODE .long 0x00b00b00 /* For asm */
#define BUG_ILLEGAL_INSTR "0x00b00b00" /* For BUG macro */
#ifndef __ASSEMBLY__
struct bug_entry {
unsigned long bug_addr;
long line;
const char *file;
const char *function;
};
struct bug_entry *find_bug(unsigned long bugaddr);
/*
* If this bit is set in the line number it means that the trap
* is for WARN_ON rather than BUG or BUG_ON.
*/
#define BUG_WARNING_TRAP 0x1000000
#ifdef CONFIG_BUG
/*
* BUG_ON() and WARN_ON() do their best to cooperate with compile-time
* optimisations. However depending on the complexity of the condition
* some compiler versions may not produce optimal results.
*/
#define BUG() do { \
__asm__ __volatile__( \
"1: twi 31,0,0\n" \
".section __bug_table,\"a\"\n" \
"\t"PPC_LONG" 1b,%0,%1,%2\n" \
".previous" \
: : "i" (__LINE__), "i" (__FILE__), "i" (__FUNCTION__)); \
} while (0)
#define BUG_ON(x) do { \
if (__builtin_constant_p(x)) { \
if (x) \
BUG(); \
} else { \
__asm__ __volatile__( \
"1: "PPC_TLNEI" %0,0\n" \
".section __bug_table,\"a\"\n" \
"\t"PPC_LONG" 1b,%1,%2,%3\n" \
".previous" \
: : "r" ((long)(x)), "i" (__LINE__), \
"i" (__FILE__), "i" (__FUNCTION__)); \
} \
} while (0)
#define WARN() do { \
__asm__ __volatile__( \
"1: twi 31,0,0\n" \
".section __bug_table,\"a\"\n" \
"\t"PPC_LONG" 1b,%0,%1,%2\n" \
".previous" \
: : "i" (__LINE__ + BUG_WARNING_TRAP), \
"i" (__FILE__), "i" (__FUNCTION__)); \
} while (0)
#define WARN_ON(x) do { \
if (__builtin_constant_p(x)) { \
if (x) \
WARN(); \
} else { \
__asm__ __volatile__( \
"1: "PPC_TLNEI" %0,0\n" \
".section __bug_table,\"a\"\n" \
"\t"PPC_LONG" 1b,%1,%2,%3\n" \
".previous" \
: : "r" ((long)(x)), \
"i" (__LINE__ + BUG_WARNING_TRAP), \
"i" (__FILE__), "i" (__FUNCTION__)); \
} \
} while (0)
#define HAVE_ARCH_BUG
#define HAVE_ARCH_BUG_ON
#define HAVE_ARCH_WARN_ON
#endif /* CONFIG_BUG */
#endif /* __ASSEMBLY __ */
#include <asm-generic/bug.h>
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_BUG_H */