diff options
| author | Gustavo Padovan <gustavo.padovan@collabora.co.uk> | 2013-09-27 11:56:14 -0300 |
|---|---|---|
| committer | Gustavo Padovan <gustavo.padovan@collabora.co.uk> | 2013-09-27 11:56:14 -0300 |
| commit | 1025c04cecd19882e28f16c4004034b475c372c5 (patch) | |
| tree | 2b7402887e86d54bff5a123228c9059eae5e32bd /arch/tile/lib/strnlen_32.c | |
| parent | 4375f1037d52602413142e290608d0d84671ad36 (diff) | |
| parent | 5bcecf325378218a8e248bb6bcae96ec7362f8ef (diff) | |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth
Conflicts:
net/bluetooth/hci_core.c
Diffstat (limited to 'arch/tile/lib/strnlen_32.c')
| -rw-r--r-- | arch/tile/lib/strnlen_32.c | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/arch/tile/lib/strnlen_32.c b/arch/tile/lib/strnlen_32.c new file mode 100644 index 00000000000..1434141d9e0 --- /dev/null +++ b/arch/tile/lib/strnlen_32.c @@ -0,0 +1,47 @@ +/* + * Copyright 2013 Tilera Corporation. All Rights Reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation, version 2. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or + * NON INFRINGEMENT. See the GNU General Public License for + * more details. + */ + +#include <linux/types.h> +#include <linux/string.h> +#include <linux/module.h> + +size_t strnlen(const char *s, size_t count) +{ + /* Get an aligned pointer. */ + const uintptr_t s_int = (uintptr_t) s; + const uint32_t *p = (const uint32_t *)(s_int & -4); + size_t bytes_read = sizeof(*p) - (s_int & (sizeof(*p) - 1)); + size_t len; + uint32_t v, bits; + + /* Avoid page fault risk by not reading any bytes when count is 0. */ + if (count == 0) + return 0; + + /* Read first word, but force bytes before the string to be nonzero. */ + v = *p | ((1 << ((s_int << 3) & 31)) - 1); + + while ((bits = __insn_seqb(v, 0)) == 0) { + if (bytes_read >= count) { + /* Read COUNT bytes and didn't find the terminator. */ + return count; + } + v = *++p; + bytes_read += sizeof(v); + } + + len = ((const char *) p) + (__insn_ctz(bits) >> 3) - s; + return (len < count ? len : count); +} +EXPORT_SYMBOL(strnlen); |