alistair23-linux/arch/arm/include/asm/bug.h
Arnd Bergmann e9c38ceba8 ARM: 8455/1: define __BUG as asm(BUG_INSTR) without CONFIG_BUG
Following (a long time after) a4b5d580e0 ("bug: Make BUG() always stop
the machine"), this adapts the ARM architecture to no longer rely
on the sub-optimal BUG() definition that has a silent endless loop
but instead use the same trapping instruction that we have for
the full BUG() support.

This avoids hundreds of warnings like

arch/arm/include/asm/xen/page.h: In function 'arbitrary_virt_to_machine':
arch/arm/include/asm/xen/page.h:85:1: warning: no return statement in function returning non-void [-Wreturn-type]

and also makes the code size slightly smaller. The behavior changes
from silently stopping the kernel to an oops, and follows what x86
does these days.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-12-03 00:02:29 +00:00

91 lines
2.4 KiB
C

#ifndef _ASMARM_BUG_H
#define _ASMARM_BUG_H
#include <linux/linkage.h>
#include <linux/types.h>
#include <asm/opcodes.h>
/*
* Use a suitable undefined instruction to use for ARM/Thumb2 bug handling.
* We need to be careful not to conflict with those used by other modules and
* the register_undef_hook() system.
*/
#ifdef CONFIG_THUMB2_KERNEL
#define BUG_INSTR_VALUE 0xde02
#define BUG_INSTR(__value) __inst_thumb16(__value)
#else
#define BUG_INSTR_VALUE 0xe7f001f2
#define BUG_INSTR(__value) __inst_arm(__value)
#endif
#define BUG() _BUG(__FILE__, __LINE__, BUG_INSTR_VALUE)
#define _BUG(file, line, value) __BUG(file, line, value)
#ifdef CONFIG_DEBUG_BUGVERBOSE
/*
* The extra indirection is to ensure that the __FILE__ string comes through
* OK. Many version of gcc do not support the asm %c parameter which would be
* preferable to this unpleasantness. We use mergeable string sections to
* avoid multiple copies of the string appearing in the kernel image.
*/
#define __BUG(__file, __line, __value) \
do { \
asm volatile("1:\t" BUG_INSTR(__value) "\n" \
".pushsection .rodata.str, \"aMS\", %progbits, 1\n" \
"2:\t.asciz " #__file "\n" \
".popsection\n" \
".pushsection __bug_table,\"a\"\n" \
".align 2\n" \
"3:\t.word 1b, 2b\n" \
"\t.hword " #__line ", 0\n" \
".popsection"); \
unreachable(); \
} while (0)
#else
#define __BUG(__file, __line, __value) \
do { \
asm volatile(BUG_INSTR(__value) "\n"); \
unreachable(); \
} while (0)
#endif /* CONFIG_DEBUG_BUGVERBOSE */
#define HAVE_ARCH_BUG
#include <asm-generic/bug.h>
struct pt_regs;
void die(const char *msg, struct pt_regs *regs, int err);
struct siginfo;
void arm_notify_die(const char *str, struct pt_regs *regs, struct siginfo *info,
unsigned long err, unsigned long trap);
#ifdef CONFIG_ARM_LPAE
#define FAULT_CODE_ALIGNMENT 33
#define FAULT_CODE_DEBUG 34
#else
#define FAULT_CODE_ALIGNMENT 1
#define FAULT_CODE_DEBUG 2
#endif
void hook_fault_code(int nr, int (*fn)(unsigned long, unsigned int,
struct pt_regs *),
int sig, int code, const char *name);
void hook_ifault_code(int nr, int (*fn)(unsigned long, unsigned int,
struct pt_regs *),
int sig, int code, const char *name);
extern asmlinkage void c_backtrace(unsigned long fp, int pmode);
struct mm_struct;
extern void show_pte(struct mm_struct *mm, unsigned long addr);
extern void __show_regs(struct pt_regs *);
#endif