2874c5fd28
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
123 lines
3.0 KiB
C
123 lines
3.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Derived from arch/ppc/mm/extable.c and arch/i386/mm/extable.c.
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*
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* Copyright (C) 2004 Paul Mackerras, IBM Corp.
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*/
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#include <linux/bsearch.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/sort.h>
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#include <linux/uaccess.h>
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#ifndef ARCH_HAS_RELATIVE_EXTABLE
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#define ex_to_insn(x) ((x)->insn)
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#else
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static inline unsigned long ex_to_insn(const struct exception_table_entry *x)
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{
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return (unsigned long)&x->insn + x->insn;
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}
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#endif
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#ifndef ARCH_HAS_SORT_EXTABLE
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#ifndef ARCH_HAS_RELATIVE_EXTABLE
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#define swap_ex NULL
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#else
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static void swap_ex(void *a, void *b, int size)
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{
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struct exception_table_entry *x = a, *y = b, tmp;
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int delta = b - a;
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tmp = *x;
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x->insn = y->insn + delta;
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y->insn = tmp.insn - delta;
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#ifdef swap_ex_entry_fixup
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swap_ex_entry_fixup(x, y, tmp, delta);
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#else
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x->fixup = y->fixup + delta;
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y->fixup = tmp.fixup - delta;
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#endif
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}
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#endif /* ARCH_HAS_RELATIVE_EXTABLE */
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/*
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* The exception table needs to be sorted so that the binary
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* search that we use to find entries in it works properly.
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* This is used both for the kernel exception table and for
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* the exception tables of modules that get loaded.
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*/
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static int cmp_ex_sort(const void *a, const void *b)
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{
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const struct exception_table_entry *x = a, *y = b;
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/* avoid overflow */
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if (ex_to_insn(x) > ex_to_insn(y))
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return 1;
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if (ex_to_insn(x) < ex_to_insn(y))
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return -1;
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return 0;
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}
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void sort_extable(struct exception_table_entry *start,
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struct exception_table_entry *finish)
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{
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sort(start, finish - start, sizeof(struct exception_table_entry),
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cmp_ex_sort, swap_ex);
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}
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#ifdef CONFIG_MODULES
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/*
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* If the exception table is sorted, any referring to the module init
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* will be at the beginning or the end.
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*/
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void trim_init_extable(struct module *m)
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{
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/*trim the beginning*/
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while (m->num_exentries &&
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within_module_init(ex_to_insn(&m->extable[0]), m)) {
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m->extable++;
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m->num_exentries--;
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}
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/*trim the end*/
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while (m->num_exentries &&
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within_module_init(ex_to_insn(&m->extable[m->num_exentries - 1]),
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m))
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m->num_exentries--;
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}
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#endif /* CONFIG_MODULES */
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#endif /* !ARCH_HAS_SORT_EXTABLE */
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#ifndef ARCH_HAS_SEARCH_EXTABLE
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static int cmp_ex_search(const void *key, const void *elt)
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{
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const struct exception_table_entry *_elt = elt;
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unsigned long _key = *(unsigned long *)key;
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/* avoid overflow */
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if (_key > ex_to_insn(_elt))
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return 1;
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if (_key < ex_to_insn(_elt))
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return -1;
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return 0;
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}
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/*
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* Search one exception table for an entry corresponding to the
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* given instruction address, and return the address of the entry,
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* or NULL if none is found.
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* We use a binary search, and thus we assume that the table is
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* already sorted.
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*/
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const struct exception_table_entry *
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search_extable(const struct exception_table_entry *base,
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const size_t num,
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unsigned long value)
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{
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return bsearch(&value, base, num,
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sizeof(struct exception_table_entry), cmp_ex_search);
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}
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#endif
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