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authorAlexander Shmelev <ashmelev@task.sun.mcst.ru>2007-08-30 06:05:29 +0200
committerAdrian Bunk <bunk@stusta.de>2007-08-30 06:05:29 +0200
commit7380487e55320420da6277820f2825ec456406eb (patch)
tree040ca512d5d582ae3dafcdd7733b72c54ca85563
parent646edb4b5b9c472944af7d6016722fa4895f3bca (diff)
downloadlinux-linaro-stable-7380487e55320420da6277820f2825ec456406eb.tar.gz
[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> Signed-off-by: Adrian Bunk <bunk@kernel.org>
-rw-r--r--arch/sparc/lib/memset.S2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/sparc/lib/memset.S b/arch/sparc/lib/memset.S
index a65eba41097c..1c37ea892deb 100644
--- a/arch/sparc/lib/memset.S
+++ b/arch/sparc/lib/memset.S
@@ -162,7 +162,7 @@ __bzero:
8:
add %o0, 1, %o0
subcc %o1, 1, %o1
- bne,a 8b
+ bne 8b
EX(stb %g3, [%o0 - 1], add %o1, 1)
0:
retl