1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * linux/arch/sparc/mm/extable.c
4*4882a593Smuzhiyun */
5*4882a593Smuzhiyun
6*4882a593Smuzhiyun #include <linux/module.h>
7*4882a593Smuzhiyun #include <linux/extable.h>
8*4882a593Smuzhiyun #include <linux/uaccess.h>
9*4882a593Smuzhiyun
sort_extable(struct exception_table_entry * start,struct exception_table_entry * finish)10*4882a593Smuzhiyun void sort_extable(struct exception_table_entry *start,
11*4882a593Smuzhiyun struct exception_table_entry *finish)
12*4882a593Smuzhiyun {
13*4882a593Smuzhiyun }
14*4882a593Smuzhiyun
15*4882a593Smuzhiyun /* Caller knows they are in a range if ret->fixup == 0 */
16*4882a593Smuzhiyun const struct exception_table_entry *
search_extable(const struct exception_table_entry * base,const size_t num,unsigned long value)17*4882a593Smuzhiyun search_extable(const struct exception_table_entry *base,
18*4882a593Smuzhiyun const size_t num,
19*4882a593Smuzhiyun unsigned long value)
20*4882a593Smuzhiyun {
21*4882a593Smuzhiyun int i;
22*4882a593Smuzhiyun
23*4882a593Smuzhiyun /* Single insn entries are encoded as:
24*4882a593Smuzhiyun * word 1: insn address
25*4882a593Smuzhiyun * word 2: fixup code address
26*4882a593Smuzhiyun *
27*4882a593Smuzhiyun * Range entries are encoded as:
28*4882a593Smuzhiyun * word 1: first insn address
29*4882a593Smuzhiyun * word 2: 0
30*4882a593Smuzhiyun * word 3: last insn address + 4 bytes
31*4882a593Smuzhiyun * word 4: fixup code address
32*4882a593Smuzhiyun *
33*4882a593Smuzhiyun * Deleted entries are encoded as:
34*4882a593Smuzhiyun * word 1: unused
35*4882a593Smuzhiyun * word 2: -1
36*4882a593Smuzhiyun *
37*4882a593Smuzhiyun * See asm/uaccess.h for more details.
38*4882a593Smuzhiyun */
39*4882a593Smuzhiyun
40*4882a593Smuzhiyun /* 1. Try to find an exact match. */
41*4882a593Smuzhiyun for (i = 0; i < num; i++) {
42*4882a593Smuzhiyun if (base[i].fixup == 0) {
43*4882a593Smuzhiyun /* A range entry, skip both parts. */
44*4882a593Smuzhiyun i++;
45*4882a593Smuzhiyun continue;
46*4882a593Smuzhiyun }
47*4882a593Smuzhiyun
48*4882a593Smuzhiyun /* A deleted entry; see trim_init_extable */
49*4882a593Smuzhiyun if (base[i].fixup == -1)
50*4882a593Smuzhiyun continue;
51*4882a593Smuzhiyun
52*4882a593Smuzhiyun if (base[i].insn == value)
53*4882a593Smuzhiyun return &base[i];
54*4882a593Smuzhiyun }
55*4882a593Smuzhiyun
56*4882a593Smuzhiyun /* 2. Try to find a range match. */
57*4882a593Smuzhiyun for (i = 0; i < (num - 1); i++) {
58*4882a593Smuzhiyun if (base[i].fixup)
59*4882a593Smuzhiyun continue;
60*4882a593Smuzhiyun
61*4882a593Smuzhiyun if (base[i].insn <= value && base[i + 1].insn > value)
62*4882a593Smuzhiyun return &base[i];
63*4882a593Smuzhiyun
64*4882a593Smuzhiyun i++;
65*4882a593Smuzhiyun }
66*4882a593Smuzhiyun
67*4882a593Smuzhiyun return NULL;
68*4882a593Smuzhiyun }
69*4882a593Smuzhiyun
70*4882a593Smuzhiyun #ifdef CONFIG_MODULES
71*4882a593Smuzhiyun /* We could memmove them around; easier to mark the trimmed ones. */
trim_init_extable(struct module * m)72*4882a593Smuzhiyun void trim_init_extable(struct module *m)
73*4882a593Smuzhiyun {
74*4882a593Smuzhiyun unsigned int i;
75*4882a593Smuzhiyun bool range;
76*4882a593Smuzhiyun
77*4882a593Smuzhiyun for (i = 0; i < m->num_exentries; i += range ? 2 : 1) {
78*4882a593Smuzhiyun range = m->extable[i].fixup == 0;
79*4882a593Smuzhiyun
80*4882a593Smuzhiyun if (within_module_init(m->extable[i].insn, m)) {
81*4882a593Smuzhiyun m->extable[i].fixup = -1;
82*4882a593Smuzhiyun if (range)
83*4882a593Smuzhiyun m->extable[i+1].fixup = -1;
84*4882a593Smuzhiyun }
85*4882a593Smuzhiyun if (range)
86*4882a593Smuzhiyun i++;
87*4882a593Smuzhiyun }
88*4882a593Smuzhiyun }
89*4882a593Smuzhiyun #endif /* CONFIG_MODULES */
90*4882a593Smuzhiyun
91*4882a593Smuzhiyun /* Special extable search, which handles ranges. Returns fixup */
search_extables_range(unsigned long addr,unsigned long * g2)92*4882a593Smuzhiyun unsigned long search_extables_range(unsigned long addr, unsigned long *g2)
93*4882a593Smuzhiyun {
94*4882a593Smuzhiyun const struct exception_table_entry *entry;
95*4882a593Smuzhiyun
96*4882a593Smuzhiyun entry = search_exception_tables(addr);
97*4882a593Smuzhiyun if (!entry)
98*4882a593Smuzhiyun return 0;
99*4882a593Smuzhiyun
100*4882a593Smuzhiyun /* Inside range? Fix g2 and return correct fixup */
101*4882a593Smuzhiyun if (!entry->fixup) {
102*4882a593Smuzhiyun *g2 = (addr - entry->insn) / 4;
103*4882a593Smuzhiyun return (entry + 1)->fixup;
104*4882a593Smuzhiyun }
105*4882a593Smuzhiyun
106*4882a593Smuzhiyun return entry->fixup;
107*4882a593Smuzhiyun }
108