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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/arch/sparc/mm/extable.c
4 */
5
6#include <linux/module.h>
7#include <linux/extable.h>
8#include <linux/uaccess.h>
9
10void sort_extable(struct exception_table_entry *start,
11 struct exception_table_entry *finish)
12{
13}
14
15/* Caller knows they are in a range if ret->fixup == 0 */
16const struct exception_table_entry *
17search_extable(const struct exception_table_entry *base,
18 const size_t num,
19 unsigned long value)
20{
21 int i;
22
23 /* Single insn entries are encoded as:
24 * word 1: insn address
25 * word 2: fixup code address
26 *
27 * Range entries are encoded as:
28 * word 1: first insn address
29 * word 2: 0
30 * word 3: last insn address + 4 bytes
31 * word 4: fixup code address
32 *
33 * Deleted entries are encoded as:
34 * word 1: unused
35 * word 2: -1
36 *
37 * See asm/uaccess.h for more details.
38 */
39
40 /* 1. Try to find an exact match. */
41 for (i = 0; i < num; i++) {
42 if (base[i].fixup == 0) {
43 /* A range entry, skip both parts. */
44 i++;
45 continue;
46 }
47
48 /* A deleted entry; see trim_init_extable */
49 if (base[i].fixup == -1)
50 continue;
51
52 if (base[i].insn == value)
53 return &base[i];
54 }
55
56 /* 2. Try to find a range match. */
57 for (i = 0; i < (num - 1); i++) {
58 if (base[i].fixup)
59 continue;
60
61 if (base[i].insn <= value && base[i + 1].insn > value)
62 return &base[i];
63
64 i++;
65 }
66
67 return NULL;
68}
69
70#ifdef CONFIG_MODULES
71/* We could memmove them around; easier to mark the trimmed ones. */
72void trim_init_extable(struct module *m)
73{
74 unsigned int i;
75 bool range;
76
77 for (i = 0; i < m->num_exentries; i += range ? 2 : 1) {
78 range = m->extable[i].fixup == 0;
79
80 if (within_module_init(m->extable[i].insn, m)) {
81 m->extable[i].fixup = -1;
82 if (range)
83 m->extable[i+1].fixup = -1;
84 }
85 if (range)
86 i++;
87 }
88}
89#endif /* CONFIG_MODULES */
90
91/* Special extable search, which handles ranges. Returns fixup */
92unsigned long search_extables_range(unsigned long addr, unsigned long *g2)
93{
94 const struct exception_table_entry *entry;
95
96 entry = search_exception_tables(addr);
97 if (!entry)
98 return 0;
99
100 /* Inside range? Fix g2 and return correct fixup */
101 if (!entry->fixup) {
102 *g2 = (addr - entry->insn) / 4;
103 return (entry + 1)->fixup;
104 }
105
106 return entry->fixup;
107}
1/*
2 * linux/arch/sparc/mm/extable.c
3 */
4
5#include <linux/module.h>
6#include <asm/uaccess.h>
7
8void sort_extable(struct exception_table_entry *start,
9 struct exception_table_entry *finish)
10{
11}
12
13/* Caller knows they are in a range if ret->fixup == 0 */
14const struct exception_table_entry *
15search_extable(const struct exception_table_entry *start,
16 const struct exception_table_entry *last,
17 unsigned long value)
18{
19 const struct exception_table_entry *walk;
20
21 /* Single insn entries are encoded as:
22 * word 1: insn address
23 * word 2: fixup code address
24 *
25 * Range entries are encoded as:
26 * word 1: first insn address
27 * word 2: 0
28 * word 3: last insn address + 4 bytes
29 * word 4: fixup code address
30 *
31 * Deleted entries are encoded as:
32 * word 1: unused
33 * word 2: -1
34 *
35 * See asm/uaccess.h for more details.
36 */
37
38 /* 1. Try to find an exact match. */
39 for (walk = start; walk <= last; walk++) {
40 if (walk->fixup == 0) {
41 /* A range entry, skip both parts. */
42 walk++;
43 continue;
44 }
45
46 /* A deleted entry; see trim_init_extable */
47 if (walk->fixup == -1)
48 continue;
49
50 if (walk->insn == value)
51 return walk;
52 }
53
54 /* 2. Try to find a range match. */
55 for (walk = start; walk <= (last - 1); walk++) {
56 if (walk->fixup)
57 continue;
58
59 if (walk[0].insn <= value && walk[1].insn > value)
60 return walk;
61
62 walk++;
63 }
64
65 return NULL;
66}
67
68#ifdef CONFIG_MODULES
69/* We could memmove them around; easier to mark the trimmed ones. */
70void trim_init_extable(struct module *m)
71{
72 unsigned int i;
73 bool range;
74
75 for (i = 0; i < m->num_exentries; i += range ? 2 : 1) {
76 range = m->extable[i].fixup == 0;
77
78 if (within_module_init(m->extable[i].insn, m)) {
79 m->extable[i].fixup = -1;
80 if (range)
81 m->extable[i+1].fixup = -1;
82 }
83 if (range)
84 i++;
85 }
86}
87#endif /* CONFIG_MODULES */
88
89/* Special extable search, which handles ranges. Returns fixup */
90unsigned long search_extables_range(unsigned long addr, unsigned long *g2)
91{
92 const struct exception_table_entry *entry;
93
94 entry = search_exception_tables(addr);
95 if (!entry)
96 return 0;
97
98 /* Inside range? Fix g2 and return correct fixup */
99 if (!entry->fixup) {
100 *g2 = (addr - entry->insn) / 4;
101 return (entry + 1)->fixup;
102 }
103
104 return entry->fixup;
105}