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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>
hifive-unleashed-5.1
Ivan Kokshaysky 2009-04-30 15:08:47 -07:00 committed by Linus Torvalds
parent 1ffb1c0c64
commit 08a42e86bc
2 changed files with 41 additions and 1 deletions
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2
arch/alpha/include/asm/uaccess.h
View File

@ -507,5 +507,7 @@ struct exception_table_entry
(pc) + (_fixup)->fixup.bits.nextinsn; \
})
#define ARCH_HAS_SORT_EXTABLE
#define ARCH_HAS_SEARCH_EXTABLE
#endif /* __ALPHA_UACCESS_H */

40
arch/alpha/mm/extable.c
View File

@ -3,11 +3,49 @@
*/
#include <linux/module.h>
#include <linux/sort.h>
#include <asm/uaccess.h>
static inline unsigned long ex_to_addr(const struct exception_table_entry *x)
{
return (unsigned long)&x->insn + x->insn;
}
static void swap_ex(void *a, void *b, int size)
{
struct exception_table_entry *ex_a = a, *ex_b = b;
unsigned long addr_a = ex_to_addr(ex_a), addr_b = ex_to_addr(ex_b);
unsigned int t = ex_a->fixup.unit;
ex_a->fixup.unit = ex_b->fixup.unit;
ex_b->fixup.unit = t;
ex_a->insn = (int)(addr_b - (unsigned long)&ex_a->insn);
ex_b->insn = (int)(addr_a - (unsigned long)&ex_b->insn);
}
/*
* 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(const void *a, const void *b)
{
const struct exception_table_entry *x = a, *y = b;
/* avoid overflow */
if (ex_to_addr(x) > ex_to_addr(y))
return 1;
if (ex_to_addr(x) < ex_to_addr(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, swap_ex);
}
const struct exception_table_entry *
@ -20,7 +58,7 @@ search_extable(const struct exception_table_entry *first,
unsigned long mid_value;
mid = (last - first) / 2 + first;
mid_value = (unsigned long)&mid->insn + mid->insn;
mid_value = ex_to_addr(mid);
if (mid_value == value)
return mid;
else if (mid_value < value)