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125 lines
3.1 KiB
125 lines
3.1 KiB
/* |
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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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* This program is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU General Public License |
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* as published by the Free Software Foundation; either version |
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* 2 of the License, or (at your option) any later version. |
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*/ |
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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 <asm/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(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, 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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/* |
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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 *first, |
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const struct exception_table_entry *last, |
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unsigned long value) |
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{ |
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while (first <= last) { |
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const struct exception_table_entry *mid; |
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mid = ((last - first) >> 1) + first; |
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/* |
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* careful, the distance between value and insn |
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* can be larger than MAX_LONG: |
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*/ |
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if (ex_to_insn(mid) < value) |
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first = mid + 1; |
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else if (ex_to_insn(mid) > value) |
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last = mid - 1; |
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else |
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return mid; |
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} |
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return NULL; |
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} |
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#endif
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