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	When building with W=1, a number of warnings are issued:
  CC      lib/extable.o
lib/extable.c:63:6: warning: no previous prototype for 'sort_extable' [-Wmissing-prototypes]
   63 | void sort_extable(struct exception_table_entry *start,
      |      ^~~~~~~~~~~~
lib/extable.c:75:6: warning: no previous prototype for 'trim_init_extable' [-Wmissing-prototypes]
   75 | void trim_init_extable(struct module *m)
      |      ^~~~~~~~~~~~~~~~~
lib/extable.c:115:1: warning: no previous prototype for 'search_extable' [-Wmissing-prototypes]
  115 | search_extable(const struct exception_table_entry *base,
      | ^~~~~~~~~~~~~~
Add the missing #include for the prototypes.
Link: http://lkml.kernel.org/r/45574.1565235784@turing-police
Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
		
	
			
		
			
				
	
	
		
			123 lines
		
	
	
	
		
			3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			123 lines
		
	
	
	
		
			3 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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#include <linux/extable.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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