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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /arch/arm64/include/asm/word-at-a-time.h | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/arm64/include/asm/word-at-a-time.h')
-rw-r--r-- | arch/arm64/include/asm/word-at-a-time.h | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/word-at-a-time.h b/arch/arm64/include/asm/word-at-a-time.h new file mode 100644 index 000000000..1c8e4f249 --- /dev/null +++ b/arch/arm64/include/asm/word-at-a-time.h @@ -0,0 +1,73 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2013 ARM Ltd. + */ +#ifndef __ASM_WORD_AT_A_TIME_H +#define __ASM_WORD_AT_A_TIME_H + +#include <linux/uaccess.h> + +#ifndef __AARCH64EB__ + +#include <linux/kernel.h> + +struct word_at_a_time { + const unsigned long one_bits, high_bits; +}; + +#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) } + +static inline unsigned long has_zero(unsigned long a, unsigned long *bits, + const struct word_at_a_time *c) +{ + unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits; + *bits = mask; + return mask; +} + +#define prep_zero_mask(a, bits, c) (bits) + +static inline unsigned long create_zero_mask(unsigned long bits) +{ + bits = (bits - 1) & ~bits; + return bits >> 7; +} + +static inline unsigned long find_zero(unsigned long mask) +{ + return fls64(mask) >> 3; +} + +#define zero_bytemask(mask) (mask) + +#else /* __AARCH64EB__ */ +#include <asm-generic/word-at-a-time.h> +#endif + +/* + * Load an unaligned word from kernel space. + * + * In the (very unlikely) case of the word being a page-crosser + * and the next page not being mapped, take the exception and + * return zeroes in the non-existing part. + */ +static inline unsigned long load_unaligned_zeropad(const void *addr) +{ + unsigned long ret; + + __uaccess_enable_tco_async(); + + /* Load word from unaligned pointer addr */ + asm( + "1: ldr %0, %2\n" + "2:\n" + _ASM_EXTABLE_LOAD_UNALIGNED_ZEROPAD(1b, 2b, %0, %1) + : "=&r" (ret) + : "r" (addr), "Q" (*(unsigned long *)addr)); + + __uaccess_disable_tco_async(); + + return ret; +} + +#endif /* __ASM_WORD_AT_A_TIME_H */ |