1 // SPDX-License-Identifier: GPL-2.0 <<
2 /* 1 /*
3 * linux/arch/arm/mm/extable.c !! 2 * linux/arch/sparc64/mm/extable.c
4 */ 3 */
5 #include <linux/extable.h> <<
6 #include <linux/uaccess.h> <<
7 4
8 int fixup_exception(struct pt_regs *regs) !! 5 #include <linux/config.h>
>> 6 #include <linux/module.h>
>> 7 #include <asm/uaccess.h>
>> 8
>> 9 extern const struct exception_table_entry __start___ex_table[];
>> 10 extern const struct exception_table_entry __stop___ex_table[];
>> 11
>> 12 static unsigned long
>> 13 search_one_table(const struct exception_table_entry *start,
>> 14 const struct exception_table_entry *end,
>> 15 unsigned long value, unsigned long *g2)
9 { 16 {
10 const struct exception_table_entry *fi !! 17 const struct exception_table_entry *walk;
11 18
12 fixup = search_exception_tables(instru !! 19 /* Single insn entries are encoded as:
13 if (fixup) { !! 20 * word 1: insn address
14 regs->ARM_pc = fixup->fixup; !! 21 * word 2: fixup code address
15 #ifdef CONFIG_THUMB2_KERNEL !! 22 *
16 /* Clear the IT state to avoid !! 23 * Range entries are encoded as:
17 regs->ARM_cpsr &= ~PSR_IT_MASK !! 24 * word 1: first insn address
18 #endif !! 25 * word 2: 0
>> 26 * word 3: last insn address + 4 bytes
>> 27 * word 4: fixup code address
>> 28 *
>> 29 * See asm/uaccess.h for more details.
>> 30 */
>> 31
>> 32 /* 1. Try to find an exact match. */
>> 33 for (walk = start; walk <= end; walk++) {
>> 34 if (walk->fixup == 0) {
>> 35 /* A range entry, skip both parts. */
>> 36 walk++;
>> 37 continue;
>> 38 }
>> 39
>> 40 if (walk->insn == value)
>> 41 return walk->fixup;
>> 42 }
>> 43
>> 44 /* 2. Try to find a range match. */
>> 45 for (walk = start; walk <= (end - 1); walk++) {
>> 46 if (walk->fixup)
>> 47 continue;
>> 48
>> 49 if (walk[0].insn <= value &&
>> 50 walk[1].insn > value) {
>> 51 *g2 = (value - walk[0].insn) / 4;
>> 52 return walk[1].fixup;
>> 53 }
>> 54 walk++;
19 } 55 }
20 56
21 return fixup != NULL; !! 57 return 0;
>> 58 }
>> 59
>> 60 extern spinlock_t modlist_lock;
>> 61
>> 62 unsigned long
>> 63 search_exception_table(unsigned long addr, unsigned long *g2)
>> 64 {
>> 65 unsigned long ret = 0, flags;
>> 66
>> 67 #ifndef CONFIG_MODULES
>> 68 /* There is only the kernel to search. */
>> 69 ret = search_one_table(__start___ex_table,
>> 70 __stop___ex_table-1, addr, g2);
>> 71 return ret;
>> 72 #else
>> 73 /* The kernel is the last "module" -- no need to treat it special. */
>> 74 struct module *mp;
>> 75
>> 76 spin_lock_irqsave(&modlist_lock, flags);
>> 77 for (mp = module_list; mp != NULL; mp = mp->next) {
>> 78 if (mp->ex_table_start == NULL || !(mp->flags & (MOD_RUNNING | MOD_INITIALIZING)))
>> 79 continue;
>> 80 ret = search_one_table(mp->ex_table_start,
>> 81 mp->ex_table_end-1, addr, g2);
>> 82 if (ret)
>> 83 break;
>> 84 }
>> 85 spin_unlock_irqrestore(&modlist_lock, flags);
>> 86 return ret;
>> 87 #endif
22 } 88 }
23 89
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