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s390/extable: use generic search and sort routines

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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.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Ard Biesheuvel 2016-03-22 14:28:14 -07:00 committed by Linus Torvalds
parent e77986b560
commit c352e8b6de
3 changed files with 2 additions and 93 deletions
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8
arch/s390/include/asm/uaccess.h
View file

@ -79,18 +79,12 @@ struct exception_table_entry
int insn, fixup;
};
static inline unsigned long extable_insn(const struct exception_table_entry *x)
{
return (unsigned long)&x->insn + x->insn;
}
static inline unsigned long extable_fixup(const struct exception_table_entry *x)
{
return (unsigned long)&x->fixup + x->fixup;
}
#define ARCH_HAS_SORT_EXTABLE
#define ARCH_HAS_SEARCH_EXTABLE
#define ARCH_HAS_RELATIVE_EXTABLE
/**
* __copy_from_user: - Copy a block of data from user space, with less checking.

2
arch/s390/mm/Makefile
View file

@ -3,7 +3,7 @@
#
obj-y := init.o fault.o extmem.o mmap.o vmem.o maccess.o
obj-y += page-states.o gup.o extable.o pageattr.o mem_detect.o
obj-y += page-states.o gup.o pageattr.o mem_detect.o
obj-y += pgtable.o pgalloc.o
obj-$(CONFIG_CMM) += cmm.o

85
arch/s390/mm/extable.c
View file

@ -1,85 +0,0 @@
#include <linux/module.h>
#include <linux/sort.h>
#include <asm/uaccess.h>
/*
* 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)
{
const struct exception_table_entry *mid;
unsigned long addr;
while (first <= last) {
mid = ((last - first) >> 1) + first;
addr = extable_insn(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 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;
/* Normalize entries to being relative to the start of the section */
for (p = start, i = 0; p < finish; p++, i += 8) {
p->insn += i;
p->fixup += i + 4;
}
sort(start, finish - start, sizeof(*start), cmp_ex, NULL);
/* Denormalize all entries */
for (p = start, i = 0; p < finish; p++, i += 8) {
p->insn -= i;
p->fixup -= 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(extable_insn(&m->extable[0]), m)) {
m->extable++;
m->num_exentries--;
}
/* Trim the end */
while (m->num_exentries &&
within_module_init(extable_insn(&m->extable[m->num_exentries-1]), m))
m->num_exentries--;
}
#endif /* CONFIG_MODULES */