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Subject[PATCH v2 4/6] x86/extable: use generic search and sort routines
Date
Replace the arch specific versions of search_extable() and sort_extable()
with calls to the generic ones, which now support relative exception
tables as well.

Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
arch/x86/include/asm/uaccess.h | 5 +-
arch/x86/mm/extable.c | 106 +-------------------
2 files changed, 4 insertions(+), 107 deletions(-)

diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 09b1b0ab94b7..6d130c4cb7de 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -106,9 +106,8 @@ static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, un
struct exception_table_entry {
int insn, fixup;
};
-/* This is not the generic standard exception_table_entry format */
-#define ARCH_HAS_SORT_EXTABLE
-#define ARCH_HAS_SEARCH_EXTABLE
+
+#define ARCH_HAS_RELATIVE_EXTABLE

extern int fixup_exception(struct pt_regs *regs);
extern int early_fixup_exception(unsigned long *ip);
diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
index 903ec1e9c326..0b172b656f43 100644
--- a/arch/x86/mm/extable.c
+++ b/arch/x86/mm/extable.c
@@ -1,14 +1,9 @@
+
#include <linux/module.h>
-#include <linux/spinlock.h>
-#include <linux/sort.h>
+
#include <asm/uaccess.h>

static inline unsigned long
-ex_insn_addr(const struct exception_table_entry *x)
-{
- return (unsigned long)&x->insn + x->insn;
-}
-static inline unsigned long
ex_fixup_addr(const struct exception_table_entry *x)
{
return (unsigned long)&x->fixup + x->fixup;
@@ -70,100 +65,3 @@ int __init early_fixup_exception(unsigned long *ip)

return 0;
}
-
-/*
- * Search one exception table for an entry corresponding to the
- * given instruction address, and return the address of the entry,
- * or NULL if none is found.
- * We use a binary search, and thus we assume that the table is
- * already sorted.
- */
-const struct exception_table_entry *
-search_extable(const struct exception_table_entry *first,
- const struct exception_table_entry *last,
- unsigned long value)
-{
- while (first <= last) {
- const struct exception_table_entry *mid;
- unsigned long addr;
-
- mid = ((last - first) >> 1) + first;
- addr = ex_insn_addr(mid);
- if (addr < value)
- first = mid + 1;
- else if (addr > value)
- last = mid - 1;
- else
- return mid;
- }
- return NULL;
-}
-
-/*
- * 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;
-
- /*
- * This value will always end up fittin in an int, because on
- * both i386 and x86-64 the kernel symbol-reachable address
- * space is < 2 GiB.
- *
- * This compare is only valid after normalization.
- */
- return x->insn - y->insn;
-}
-
-void sort_extable(struct exception_table_entry *start,
- struct exception_table_entry *finish)
-{
- struct exception_table_entry *p;
- int i;
-
- /* Convert all entries to being relative to the start of the section */
- i = 0;
- for (p = start; p < finish; p++) {
- p->insn += i;
- i += 4;
- p->fixup += i;
- i += 4;
- }
-
- sort(start, finish - start, sizeof(struct exception_table_entry),
- cmp_ex, NULL);
-
- /* Denormalize all entries */
- i = 0;
- for (p = start; p < finish; p++) {
- p->insn -= i;
- i += 4;
- p->fixup -= i;
- i += 4;
- }
-}
-
-#ifdef CONFIG_MODULES
-/*
- * If the exception table is sorted, any referring to the module init
- * will be at the beginning or the end.
- */
-void trim_init_extable(struct module *m)
-{
- /*trim the beginning*/
- while (m->num_exentries &&
- within_module_init(ex_insn_addr(&m->extable[0]), m)) {
- m->extable++;
- m->num_exentries--;
- }
- /*trim the end*/
- while (m->num_exentries &&
- within_module_init(ex_insn_addr(&m->extable[m->num_exentries-1]), m))
- m->num_exentries--;
-}
-#endif /* CONFIG_MODULES */
--
2.5.0


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