forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
118 lines
2.9 KiB
118 lines
2.9 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
|
/* |
|
* Derived from arch/ppc/mm/extable.c and arch/i386/mm/extable.c. |
|
* |
|
* Copyright (C) 2004 Paul Mackerras, IBM Corp. |
|
*/ |
|
|
|
#include <linux/bsearch.h> |
|
#include <linux/module.h> |
|
#include <linux/init.h> |
|
#include <linux/sort.h> |
|
#include <linux/uaccess.h> |
|
#include <linux/extable.h> |
|
|
|
#ifndef ARCH_HAS_RELATIVE_EXTABLE |
|
#define ex_to_insn(x) ((x)->insn) |
|
#else |
|
static inline unsigned long ex_to_insn(const struct exception_table_entry *x) |
|
{ |
|
return (unsigned long)&x->insn + x->insn; |
|
} |
|
#endif |
|
|
|
#ifndef ARCH_HAS_RELATIVE_EXTABLE |
|
#define swap_ex NULL |
|
#else |
|
static void swap_ex(void *a, void *b, int size) |
|
{ |
|
struct exception_table_entry *x = a, *y = b, tmp; |
|
int delta = b - a; |
|
|
|
tmp = *x; |
|
x->insn = y->insn + delta; |
|
y->insn = tmp.insn - delta; |
|
|
|
#ifdef swap_ex_entry_fixup |
|
swap_ex_entry_fixup(x, y, tmp, delta); |
|
#else |
|
x->fixup = y->fixup + delta; |
|
y->fixup = tmp.fixup - delta; |
|
#endif |
|
} |
|
#endif /* ARCH_HAS_RELATIVE_EXTABLE */ |
|
|
|
/* |
|
* The exception table needs to be sorted so that the binary |
|
* search that we use to find entries in it works properly. |
|
* This is used both for the kernel exception table and for |
|
* the exception tables of modules that get loaded. |
|
*/ |
|
static int cmp_ex_sort(const void *a, const void *b) |
|
{ |
|
const struct exception_table_entry *x = a, *y = b; |
|
|
|
/* avoid overflow */ |
|
if (ex_to_insn(x) > ex_to_insn(y)) |
|
return 1; |
|
if (ex_to_insn(x) < ex_to_insn(y)) |
|
return -1; |
|
return 0; |
|
} |
|
|
|
void sort_extable(struct exception_table_entry *start, |
|
struct exception_table_entry *finish) |
|
{ |
|
sort(start, finish - start, sizeof(struct exception_table_entry), |
|
cmp_ex_sort, swap_ex); |
|
} |
|
|
|
#ifdef CONFIG_MODULES |
|
/* |
|
* If the exception table is sorted, any referring to the module init |
|
* will be at the beginning or the end. |
|
*/ |
|
void trim_init_extable(struct module *m) |
|
{ |
|
/*trim the beginning*/ |
|
while (m->num_exentries && |
|
within_module_init(ex_to_insn(&m->extable[0]), m)) { |
|
m->extable++; |
|
m->num_exentries--; |
|
} |
|
/*trim the end*/ |
|
while (m->num_exentries && |
|
within_module_init(ex_to_insn(&m->extable[m->num_exentries - 1]), |
|
m)) |
|
m->num_exentries--; |
|
} |
|
#endif /* CONFIG_MODULES */ |
|
|
|
static int cmp_ex_search(const void *key, const void *elt) |
|
{ |
|
const struct exception_table_entry *_elt = elt; |
|
unsigned long _key = *(unsigned long *)key; |
|
|
|
/* avoid overflow */ |
|
if (_key > ex_to_insn(_elt)) |
|
return 1; |
|
if (_key < ex_to_insn(_elt)) |
|
return -1; |
|
return 0; |
|
} |
|
|
|
/* |
|
* Search one exception table for an entry corresponding to the |
|
* given instruction address, and return the address of the entry, |
|
* or NULL if none is found. |
|
* We use a binary search, and thus we assume that the table is |
|
* already sorted. |
|
*/ |
|
const struct exception_table_entry * |
|
search_extable(const struct exception_table_entry *base, |
|
const size_t num, |
|
unsigned long value) |
|
{ |
|
return bsearch(&value, base, num, |
|
sizeof(struct exception_table_entry), cmp_ex_search); |
|
}
|
|
|