1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __S390_EXTABLE_H
3 #define __S390_EXTABLE_H
4
5 #include <asm/ptrace.h>
6 #include <linux/compiler.h>
7
8 /*
9 * The exception table consists of three addresses:
10 *
11 * - Address of an instruction that is allowed to fault.
12 * - Address at which the program should continue.
13 * - Optional address of handler that takes pt_regs * argument and runs in
14 * interrupt context.
15 *
16 * No registers are modified, so it is entirely up to the continuation code
17 * to figure out what to do.
18 *
19 * All the routines below use bits of fixup code that are out of line
20 * with the main instruction path. This means when everything is well,
21 * we don't even have to jump over them. Further, they do not intrude
22 * on our cache or tlb entries.
23 */
24
25 struct exception_table_entry
26 {
27 int insn, fixup;
28 short type, data;
29 };
30
31 extern struct exception_table_entry *__start_amode31_ex_table;
32 extern struct exception_table_entry *__stop_amode31_ex_table;
33
34 const struct exception_table_entry *s390_search_extables(unsigned long addr);
35
36 static inline unsigned long extable_fixup(const struct exception_table_entry *x)
37 {
38 return (unsigned long)&x->fixup + x->fixup;
39 }
40
41 #define ARCH_HAS_RELATIVE_EXTABLE
42
43 static inline void swap_ex_entry_fixup(struct exception_table_entry *a,
44 struct exception_table_entry *b,
45 struct exception_table_entry tmp,
46 int delta)
47 {
48 a->fixup = b->fixup + delta;
49 b->fixup = tmp.fixup - delta;
50 a->type = b->type;
51 b->type = tmp.type;
52 a->data = b->data;
53 b->data = tmp.data;
54 }
55 #define swap_ex_entry_fixup swap_ex_entry_fixup
56
57 #ifdef CONFIG_BPF_JIT
58
59 bool ex_handler_bpf(const struct exception_table_entry *ex, struct pt_regs *regs);
60
61 #else /* !CONFIG_BPF_JIT */
62
63 static inline bool ex_handler_bpf(const struct exception_table_entry *ex, struct pt_regs *regs)
64 {
65 return false;
66 }
67
68 #endif /* CONFIG_BPF_JIT */
69
70 bool fixup_exception(struct pt_regs *regs);
71
72 #endif
73
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