1/* SPDX-License-Identifier: GPL-2.0-only */ 2/* 3 * Copyright (C) 2012 Regents of the University of California 4 * 5 * Derived from arch/x86/include/asm/word-at-a-time.h 6 */ 7 8#ifndef _ASM_RISCV_WORD_AT_A_TIME_H 9#define _ASM_RISCV_WORD_AT_A_TIME_H 10 11 12#include <asm/asm-extable.h> 13#include <linux/bitops.h> 14#include <linux/wordpart.h> 15 16struct word_at_a_time { 17 const unsigned long one_bits, high_bits; 18}; 19 20#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) } 21 22static inline unsigned long has_zero(unsigned long val, 23 unsigned long *bits, const struct word_at_a_time *c) 24{ 25 unsigned long mask = ((val - c->one_bits) & ~val) & c->high_bits; 26 *bits = mask; 27 return mask; 28} 29 30static inline unsigned long prep_zero_mask(unsigned long val, 31 unsigned long bits, const struct word_at_a_time *c) 32{ 33 return bits; 34} 35 36static inline unsigned long create_zero_mask(unsigned long bits) 37{ 38 bits = (bits - 1) & ~bits; 39 return bits >> 7; 40} 41 42static inline unsigned long find_zero(unsigned long mask) 43{ 44 return fls64(mask) >> 3; 45} 46 47/* The mask we created is directly usable as a bytemask */ 48#define zero_bytemask(mask) (mask) 49 50#ifdef CONFIG_DCACHE_WORD_ACCESS 51 52/* 53 * Load an unaligned word from kernel space. 54 * 55 * In the (very unlikely) case of the word being a page-crosser 56 * and the next page not being mapped, take the exception and 57 * return zeroes in the non-existing part. 58 */ 59static inline unsigned long load_unaligned_zeropad(const void *addr) 60{ 61 unsigned long ret; 62 63 /* Load word from unaligned pointer addr */ 64 asm( 65 "1: " REG_L " %0, %2\n" 66 "2:\n" 67 _ASM_EXTABLE_LOAD_UNALIGNED_ZEROPAD(1b, 2b, %0, %1) 68 : "=&r" (ret) 69 : "r" (addr), "m" (*(unsigned long *)addr)); 70 71 return ret; 72} 73 74#endif /* CONFIG_DCACHE_WORD_ACCESS */ 75 76#endif /* _ASM_RISCV_WORD_AT_A_TIME_H */ 77