xref: /openbmc/linux/arch/s390/include/asm/extable.h (revision 3d66718c)
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 
extable_fixup(const struct exception_table_entry * x)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 
swap_ex_entry_fixup(struct exception_table_entry * a,struct exception_table_entry * b,struct exception_table_entry tmp,int delta)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 
ex_handler_bpf(const struct exception_table_entry * ex,struct pt_regs * regs)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