linux/arch/sparc
Alexander Shmelev f61698e648 [SPARC32]: Fix bug in sparc optimized memset.
Sparc optimized memset (arch/sparc/lib/memset.S) does not fill last
byte of the memory area, if area size is less than 8 bytes and start
address is not word (4-bytes) aligned.

Here is code chunk where bug located:
/* %o0 - memory address, %o1 - size, %g3 - value */
8:
     add    %o0, 1, %o0
    subcc    %o1, 1, %o1
    bne,a    8b
     stb %g3, [%o0 - 1]

This code should write byte every loop iteration, but last time delay
instruction stb is not executed because branch instruction sets
"annul" bit.

Patch replaces bne,a by bne instruction.

Error can be reproduced by simple kernel module:

--------------------
#include <linux/module.h>
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <string.h>

static void do_memset(void **p, int size)
{
        memset(p, 0x00, size);
}

static int __init memset_test_init(void)
{
    char fooc[8];
    int *fooi;
    memset(fooc, 0xba, sizeof(fooc));

    do_memset((void**)(fooc + 3), 1);

    fooi = (int*) fooc;
    printk("%08X %08X\n", fooi[0], fooi[1]);

    return -1;
}

static void __exit memset_test_cleanup(void)
{
    return;
}

module_init(memset_test_init);
module_exit(memset_test_cleanup);

MODULE_LICENSE("GPL");
EXPORT_NO_SYMBOLS;
--------------------

Signed-off-by: Alexander Shmelev <ashmelev@task.sun.mcst.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-07-24 13:41:44 -07:00
..
boot Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
kernel [SPARC]: Add missing NOTES section. 2007-07-24 13:24:34 -07:00
lib [SPARC32]: Fix bug in sparc optimized memset. 2007-07-24 13:41:44 -07:00
math-emu kbuild: use relative path to -I 2006-04-04 16:56:10 +02:00
mm [SPARC32]: Make PAGE_SHARED a read-mostly variable. 2007-07-21 19:20:34 -07:00
oprofile [SPARC]: Add sparc profiling support 2006-10-17 19:28:53 -07:00
prom [SPARC32]: missing exports 2007-07-24 13:24:33 -07:00
Kconfig Start split out of common open firmware code 2007-07-20 13:28:41 +10:00
Kconfig.debug Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
Makefile [SPARC]: Add sparc profiling support 2006-10-17 19:28:53 -07:00
defconfig [SPARC32]: Deal with rtc/sun_mostek_rtc conflict. 2007-07-24 13:24:32 -07:00