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authorIvan Kokshaysky <ink@jurassic.park.msu.ru>2009-04-30 18:08:47 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2009-05-02 18:36:10 -0400
commit08a42e86bce511b45ca3eee40f51674b02a777d1 (patch)
tree48a518301cf5a7bf9fecbdb554668a68cfb454c2 /arch/alpha
parent1ffb1c0c64b4a2b75eed1f63cc47f2beb711c92f (diff)
alpha: exception table sorting
Exception fixups for sections other than .text (like one in futex_init()) break the natural ordering of fixup entries, so sorting is required. Without that the result of the exception table search depends on phase of the moon. Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Richard Henderson <rth@twiddle.net Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/alpha')
-rw-r--r--arch/alpha/include/asm/uaccess.h2
-rw-r--r--arch/alpha/mm/extable.c40
2 files changed, 41 insertions, 1 deletions
diff --git a/arch/alpha/include/asm/uaccess.h b/arch/alpha/include/asm/uaccess.h
index 163f3053001c..b49ec2f8d6e3 100644
--- a/arch/alpha/include/asm/uaccess.h
+++ b/arch/alpha/include/asm/uaccess.h
@@ -507,5 +507,7 @@ struct exception_table_entry
507 (pc) + (_fixup)->fixup.bits.nextinsn; \ 507 (pc) + (_fixup)->fixup.bits.nextinsn; \
508}) 508})
509 509
510#define ARCH_HAS_SORT_EXTABLE
511#define ARCH_HAS_SEARCH_EXTABLE
510 512
511#endif /* __ALPHA_UACCESS_H */ 513#endif /* __ALPHA_UACCESS_H */
diff --git a/arch/alpha/mm/extable.c b/arch/alpha/mm/extable.c
index dc7aeda15773..62dc379d301a 100644
--- a/arch/alpha/mm/extable.c
+++ b/arch/alpha/mm/extable.c
@@ -3,11 +3,49 @@
3 */ 3 */
4 4
5#include <linux/module.h> 5#include <linux/module.h>
6#include <linux/sort.h>
6#include <asm/uaccess.h> 7#include <asm/uaccess.h>
7 8
9static inline unsigned long ex_to_addr(const struct exception_table_entry *x)
10{
11 return (unsigned long)&x->insn + x->insn;
12}
13
14static void swap_ex(void *a, void *b, int size)
15{
16 struct exception_table_entry *ex_a = a, *ex_b = b;
17 unsigned long addr_a = ex_to_addr(ex_a), addr_b = ex_to_addr(ex_b);
18 unsigned int t = ex_a->fixup.unit;
19
20 ex_a->fixup.unit = ex_b->fixup.unit;
21 ex_b->fixup.unit = t;
22 ex_a->insn = (int)(addr_b - (unsigned long)&ex_a->insn);
23 ex_b->insn = (int)(addr_a - (unsigned long)&ex_b->insn);
24}
25
26/*
27 * The exception table needs to be sorted so that the binary
28 * search that we use to find entries in it works properly.
29 * This is used both for the kernel exception table and for
30 * the exception tables of modules that get loaded.
31 */
32static int cmp_ex(const void *a, const void *b)
33{
34 const struct exception_table_entry *x = a, *y = b;
35
36 /* avoid overflow */
37 if (ex_to_addr(x) > ex_to_addr(y))
38 return 1;
39 if (ex_to_addr(x) < ex_to_addr(y))
40 return -1;
41 return 0;
42}
43
8void sort_extable(struct exception_table_entry *start, 44void sort_extable(struct exception_table_entry *start,
9 struct exception_table_entry *finish) 45 struct exception_table_entry *finish)
10{ 46{
47 sort(start, finish - start, sizeof(struct exception_table_entry),
48 cmp_ex, swap_ex);
11} 49}
12 50
13const struct exception_table_entry * 51const struct exception_table_entry *
@@ -20,7 +58,7 @@ search_extable(const struct exception_table_entry *first,
20 unsigned long mid_value; 58 unsigned long mid_value;
21 59
22 mid = (last - first) / 2 + first; 60 mid = (last - first) / 2 + first;
23 mid_value = (unsigned long)&mid->insn + mid->insn; 61 mid_value = ex_to_addr(mid);
24 if (mid_value == value) 62 if (mid_value == value)
25 return mid; 63 return mid;
26 else if (mid_value < value) 64 else if (mid_value < value)