diff options
author | Chris Metcalf <cmetcalf@tilera.com> | 2011-05-04 18:38:26 (GMT) |
---|---|---|
committer | Chris Metcalf <cmetcalf@tilera.com> | 2011-05-12 19:52:12 (GMT) |
commit | 18aecc2b645bbb07851b196452a2af314222069b (patch) | |
tree | 959f765f69af01046c6e26db12b45c3390799d3e /arch/tile/lib/memchr_64.c | |
parent | be84cb43833ee40a42e08f5425d20310f16229c7 (diff) | |
download | linux-fsl-qoriq-18aecc2b645bbb07851b196452a2af314222069b.tar.xz |
arch/tile: finish enabling support for TILE-Gx 64-bit chip
This support was partially present in the existing code (look for
"__tilegx__" ifdefs) but with this change you can build a working
kernel using the TILE-Gx toolchain and ARCH=tilegx.
Most of these files are new, generally adding a foo_64.c file
where previously there was just a foo_32.c file.
The ARCH=tilegx directive redirects to arch/tile, not arch/tilegx,
using the existing SRCARCH mechanism in the top-level Makefile.
Changes to existing files:
- <asm/bitops.h> and <asm/bitops_32.h> changed to factor the
include of <asm-generic/bitops/non-atomic.h> in the common header.
- <asm/compat.h> and arch/tile/kernel/compat.c changed to remove
the "const" markers I had put on compat_sys_execve() when trying
to match some recent similar changes to the non-compat execve.
It turns out the compat version wasn't "upgraded" to use const.
- <asm/opcode-tile_64.h> and <asm/opcode_constants_64.h> were
previously included accidentally, with the 32-bit contents. Now
they have the proper 64-bit contents.
Finally, I had to hack the existing hacky drivers/input/input-compat.h
to add yet another "#ifdef" for INPUT_COMPAT_TEST (same as x86_64).
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> [drivers/input]
Diffstat (limited to 'arch/tile/lib/memchr_64.c')
-rw-r--r-- | arch/tile/lib/memchr_64.c | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/arch/tile/lib/memchr_64.c b/arch/tile/lib/memchr_64.c new file mode 100644 index 0000000..84fdc8d --- /dev/null +++ b/arch/tile/lib/memchr_64.c @@ -0,0 +1,71 @@ +/* + * Copyright 2011 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> + +void *memchr(const void *s, int c, size_t n) +{ + const uint64_t *last_word_ptr; + const uint64_t *p; + const char *last_byte_ptr; + uintptr_t s_int; + uint64_t goal, before_mask, v, bits; + char *ret; + + if (__builtin_expect(n == 0, 0)) { + /* Don't dereference any memory if the array is empty. */ + return NULL; + } + + /* Get an aligned pointer. */ + s_int = (uintptr_t) s; + p = (const uint64_t *)(s_int & -8); + + /* Create eight copies of the byte for which we are looking. */ + goal = 0x0101010101010101ULL * (uint8_t) c; + + /* Read the first word, but munge it so that bytes before the array + * will not match goal. + * + * Note that this shift count expression works because we know + * shift counts are taken mod 64. + */ + before_mask = (1ULL << (s_int << 3)) - 1; + v = (*p | before_mask) ^ (goal & before_mask); + + /* Compute the address of the last byte. */ + last_byte_ptr = (const char *)s + n - 1; + + /* Compute the address of the word containing the last byte. */ + last_word_ptr = (const uint64_t *)((uintptr_t) last_byte_ptr & -8); + + while ((bits = __insn_v1cmpeq(v, goal)) == 0) { + if (__builtin_expect(p == last_word_ptr, 0)) { + /* We already read the last word in the array, + * so give up. + */ + return NULL; + } + v = *++p; + } + + /* We found a match, but it might be in a byte past the end + * of the array. + */ + ret = ((char *)p) + (__insn_ctz(bits) >> 3); + return (ret <= last_byte_ptr) ? ret : NULL; +} +EXPORT_SYMBOL(memchr); |