1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * Copyright (C) 2013 ARM Ltd. 4 */ 5 #ifndef __ASM_WORD_AT_A_TIME_H 6 #define __ASM_WORD_AT_A_TIME_H 7 8 #include <linux/uaccess.h> 9 10 #ifndef __AARCH64EB__ 11 12 #include <linux/bitops.h> 13 #include <linux/wordpart.h> 14 15 struct word_at_a_time { 16 const unsigned long one_bits, high_bits; 17 }; 18 19 #define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) } 20 21 static inline unsigned long has_zero(unsigned long a, unsigned long *bits, 22 const struct word_at_a_time *c) 23 { 24 unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits; 25 *bits = mask; 26 return mask; 27 } 28 29 #define prep_zero_mask(a, bits, c) (bits) 30 31 static inline unsigned long create_zero_mask(unsigned long bits) 32 { 33 bits = (bits - 1) & ~bits; 34 return bits >> 7; 35 } 36 37 static inline unsigned long find_zero(unsigned long mask) 38 { 39 return fls64(mask) >> 3; 40 } 41 42 #define zero_bytemask(mask) (mask) 43 44 #else /* __AARCH64EB__ */ 45 #include <asm-generic/word-at-a-time.h> 46 #endif 47 48 /* 49 * Load an unaligned word from kernel space. 50 * 51 * In the (very unlikely) case of the word being a page-crosser 52 * and the next page not being mapped, take the exception and 53 * return zeroes in the non-existing part. 54 */ 55 static inline unsigned long load_unaligned_zeropad(const void *addr) 56 { 57 unsigned long ret; 58 59 __mte_enable_tco_async(); 60 61 /* Load word from unaligned pointer addr */ 62 asm( 63 "1: ldr %0, %2\n" 64 "2:\n" 65 _ASM_EXTABLE_LOAD_UNALIGNED_ZEROPAD(1b, 2b, %0, %1) 66 : "=&r" (ret) 67 : "r" (addr), "Q" (*(unsigned long *)addr)); 68 69 __mte_disable_tco_async(); 70 71 return ret; 72 } 73 74 #endif /* __ASM_WORD_AT_A_TIME_H */ 75