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author | Linus Torvalds <torvalds@linux-foundation.org> | 2013-09-06 11:14:33 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-09-06 11:14:33 -0700 |
commit | 4de9ad9bc08b4953fc03336ad38908496e2f8826 (patch) | |
tree | bd44add223061a58317034a0d6c9686d95d12fba /arch/tile/lib/strnlen_64.c | |
parent | 576c25eb5954035b64112188d9a2683144600f3d (diff) | |
parent | 06da6629e68ddc8ffe2933d33b3681f09104b3f1 (diff) | |
download | op-kernel-dev-4de9ad9bc08b4953fc03336ad38908496e2f8826.zip op-kernel-dev-4de9ad9bc08b4953fc03336ad38908496e2f8826.tar.gz |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile
Pull Tile arch updates from Chris Metcalf:
"These changes bring in a bunch of new functionality that has been
maintained internally at Tilera over the last year, plus other stray
bits of work that I've taken into the tile tree from other folks.
The changes include some PCI root complex work, interrupt-driven
console support, support for performing fast-path unaligned data
fixups by kernel-based JIT code generation, CONFIG_PREEMPT support,
vDSO support for gettimeofday(), a serial driver for the tilegx
on-chip UART, KGDB support, more optimized string routines, support
for ftrace and kprobes, improved ASLR, and many bug fixes.
We also remove support for the old TILE64 chip, which is no longer
buildable"
* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile: (85 commits)
tile: refresh tile defconfig files
tile: rework <asm/cmpxchg.h>
tile PCI RC: make default consistent DMA mask 32-bit
tile: add null check for kzalloc in tile/kernel/setup.c
tile: make __write_once a synonym for __read_mostly
tile: remove support for TILE64
tile: use asm-generic/bitops/builtin-*.h
tile: eliminate no-op "noatomichash" boot argument
tile: use standard tile_bundle_bits type in traps.c
tile: simplify code referencing hypervisor API addresses
tile: change <asm/system.h> to <asm/switch_to.h> in comments
tile: mark pcibios_init() as __init
tile: check for correct compiler earlier in asm-offsets.c
tile: use standard 'generic-y' model for <asm/hw_irq.h>
tile: use asm-generic version of <asm/local64.h>
tile PCI RC: add comment about "PCI hole" problem
tile: remove DEBUG_EXTRA_FLAGS kernel config option
tile: add virt_to_kpte() API and clean up and document behavior
tile: support FRAME_POINTER
tile: support reporting Tilera hypervisor statistics
...
Diffstat (limited to 'arch/tile/lib/strnlen_64.c')
-rw-r--r-- | arch/tile/lib/strnlen_64.c | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/arch/tile/lib/strnlen_64.c b/arch/tile/lib/strnlen_64.c new file mode 100644 index 0000000..2e8de6a --- /dev/null +++ b/arch/tile/lib/strnlen_64.c @@ -0,0 +1,48 @@ +/* + * 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> +#include "string-endian.h" + +size_t strnlen(const char *s, size_t count) +{ + /* Get an aligned pointer. */ + const uintptr_t s_int = (uintptr_t) s; + const uint64_t *p = (const uint64_t *)(s_int & -8); + size_t bytes_read = sizeof(*p) - (s_int & (sizeof(*p) - 1)); + size_t len; + uint64_t v, bits; + + /* Avoid page fault risk by not reading any bytes when count is 0. */ + if (count == 0) + return 0; + + /* Read and MASK the first word. */ + v = *p | MASK(s_int); + + while ((bits = __insn_v1cmpeqi(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) + (CFZ(bits) >> 3) - s; + return (len < count ? len : count); +} +EXPORT_SYMBOL(strnlen); |