linux/arch/s390/include/asm/extable.h
Heiko Carstens 3d66718cd6 s390/extable: convert to relative table with data
Follow arm64, riscv, and x86 and change extable layout to common
"relative table with data". This allows to get rid of s390 specific
code in sorttable.c.

The main difference to before is that extable entries do not contain a
relative function pointer anymore. Instead data and type fields are
added.

The type field is used to indicate which exception handler needs to be
called, while the data field is currently unused.

Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2022-03-08 00:33:00 +01:00

73 lines
1.9 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __S390_EXTABLE_H
#define __S390_EXTABLE_H
#include <asm/ptrace.h>
#include <linux/compiler.h>
/*
* The exception table consists of three addresses:
*
* - Address of an instruction that is allowed to fault.
* - Address at which the program should continue.
* - Optional address of handler that takes pt_regs * argument and runs in
* interrupt context.
*
* 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;
};
extern struct exception_table_entry *__start_amode31_ex_table;
extern struct exception_table_entry *__stop_amode31_ex_table;
const struct exception_table_entry *s390_search_extables(unsigned long addr);
static inline unsigned long extable_fixup(const struct exception_table_entry *x)
{
return (unsigned long)&x->fixup + x->fixup;
}
#define ARCH_HAS_RELATIVE_EXTABLE
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->type = b->type;
b->type = tmp.type;
a->data = b->data;
b->data = tmp.data;
}
#define swap_ex_entry_fixup swap_ex_entry_fixup
#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