name : word-at-a-time.h /* 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; __mte_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)); __mte_disable_tco_async(); return ret; } #endif /* __ASM_WORD_AT_A_TIME_H */