arch/parisc/include/asm/extable.h

Source file repositories/reference/linux-study-clean/arch/parisc/include/asm/extable.h

File Facts

System
Linux kernel
Corpus path
arch/parisc/include/asm/extable.h
Extension
.h
Size
2222 bytes
Lines
65
Domain
Architecture Layer
Bucket
arch/parisc
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

struct exception_table_entry {
	int insn;	/* relative address of insn that is allowed to fault. */
	int fixup;	/* relative address of fixup routine */
	int err_opcode; /* sample opcode with register which holds error code */
};

#define ASM_EXCEPTIONTABLE_ENTRY( fault_addr, except_addr, opcode )\
	".section __ex_table,\"aw\"\n"			   \
	".align 4\n"					   \
	".word (" #fault_addr " - .), (" #except_addr " - .)\n" \
	opcode "\n"					   \
	".previous\n"

/*
 * ASM_EXCEPTIONTABLE_ENTRY_EFAULT() creates a special exception table entry
 * (with lowest bit set) for which the fault handler in fixup_exception() will
 * load -EFAULT on fault into the register specified by the err_opcode instruction,
 * and zeroes the target register in case of a read fault in get_user().
 */
#define ASM_EXCEPTIONTABLE_VAR(__err_var)		\
	int __err_var = 0
#define ASM_EXCEPTIONTABLE_ENTRY_EFAULT( fault_addr, except_addr, register )\
	ASM_EXCEPTIONTABLE_ENTRY( fault_addr, except_addr + 1, "or %%r0,%%r0," register)

static inline void swap_ex_entry_fixup(struct exception_table_entry *a,
				       struct exception_table_entry *b,
				       struct exception_table_entry tmp,
				       int delta)
{
	a->fixup = b->fixup + delta;
	b->fixup = tmp.fixup - delta;
	a->err_opcode = b->err_opcode;
	b->err_opcode = tmp.err_opcode;
}
#define swap_ex_entry_fixup swap_ex_entry_fixup

#endif

Annotation

Implementation Notes