From f61698e6489f229f9fcfe29e68f228389a772993 Mon Sep 17 00:00:00 2001 From: Alexander Shmelev Date: Tue, 24 Jul 2007 13:41:44 -0700 Subject: [PATCH] [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 #include #include #include #include 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 Signed-off-by: David S. Miller --- arch/sparc/lib/memset.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/sparc/lib/memset.S b/arch/sparc/lib/memset.S index a65eba41097..1c37ea892de 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 -- 2.20.1