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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119// 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)#elsestatic 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#elsestatic 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);}