xref: /kernel/linux/linux-6.6/arch/arm64/include/asm/extable.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __ASM_EXTABLE_H
#define __ASM_EXTABLE_H

/*
 * The exception table consists of pairs of relative offsets: the first
 * is the relative offset to an instruction that is allowed to fault,
 * and the second is the relative offset at which the program should
 * continue. No registers are modified, so it is entirely up to the
 * continuation code to figure out what to do.
 *
 * All the routines below use bits of fixup code that are out of line
 * with the main instruction path.  This means when everything is well,
 * we don't even have to jump over them.  Further, they do not intrude
 * on our cache or tlb entries.
 */

struct exception_table_entry
{
	int insn, fixup;
	short type, data;
};

#define ARCH_HAS_RELATIVE_EXTABLE

#define swap_ex_entry_fixup(a, b, tmp, delta)		\
do {							\
	(a)->fixup = (b)->fixup + (delta);		\
	(b)->fixup = (tmp).fixup - (delta);		\
	(a)->type = (b)->type;				\
	(b)->type = (tmp).type;				\
	(a)->data = (b)->data;				\
	(b)->data = (tmp).data;				\
} while (0)

#ifdef CONFIG_BPF_JIT
bool ex_handler_bpf(const struct exception_table_entry *ex,
		    struct pt_regs *regs);
#else /* !CONFIG_BPF_JIT */
static inline
bool ex_handler_bpf(const struct exception_table_entry *ex,
		    struct pt_regs *regs)
{
	return false;
}
#endif /* !CONFIG_BPF_JIT */

bool fixup_exception(struct pt_regs *regs);
#endif