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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2012 Regents of the University of California
*
* Derived from arch/x86/include/asm/word-at-a-time.h
*/
#ifndef _ASM_RISCV_WORD_AT_A_TIME_H
#define _ASM_RISCV_WORD_AT_A_TIME_H
#include <asm/asm-extable.h>
#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 val,
unsigned long *bits, const struct word_at_a_time *c)
{
unsigned long mask = ((val - c->one_bits) & ~val) & c->high_bits;
*bits = mask;
return mask;
}
static inline unsigned long prep_zero_mask(unsigned long val,
unsigned long bits, const struct word_at_a_time *c)
{
return 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;
}
/* The mask we created is directly usable as a bytemask */
#define zero_bytemask(mask) (mask)
#ifdef CONFIG_DCACHE_WORD_ACCESS
/*
* 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;
/* Load word from unaligned pointer addr */
asm(
"1: " REG_L " %0, %2\n"
"2:\n"
_ASM_EXTABLE_LOAD_UNALIGNED_ZEROPAD(1b, 2b, %0, %1)
: "=&r" (ret)
: "r" (addr), "m" (*(unsigned long *)addr));
return ret;
}
#endif /* CONFIG_DCACHE_WORD_ACCESS */
#endif /* _ASM_RISCV_WORD_AT_A_TIME_H */
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