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Commit c352e8b6 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Linus Torvalds
Browse files

s390/extable: use generic search and sort routines 



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: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e77986b5

arch/s390/include/asm/uaccess.h

+1 −7
Original line number Diff line number Diff line
@@ -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.

arch/s390/mm/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -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

arch/s390/mm/extable.c

deleted100644 → 0
+0 −85
Original line number Diff line number Diff line 
#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 */