/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_WORD_AT_A_TIME_H
#define _ASM_WORD_AT_A_TIME_H

#include <linux/bitops.h>
#include <linux/wordpart.h>
#include <asm/asm-extable.h>
#include <asm/bitsperlong.h>

struct word_at_a_time {
        const unsigned long bits;
};

#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x7f) }

static inline unsigned long prep_zero_mask(unsigned long val, unsigned long data, const struct word_at_a_time *c)
{
        return data;
}

static inline unsigned long create_zero_mask(unsigned long data)
{
        return __fls(data);
}

static inline unsigned long find_zero(unsigned long data)
{
        return (data ^ (BITS_PER_LONG - 1)) >> 3;
}

static inline unsigned long has_zero(unsigned long val, unsigned long *data, const struct word_at_a_time *c)
{
        unsigned long mask = (val & c->bits) + c->bits;

        *data = ~(mask | val | c->bits);
        return *data;
}

static inline unsigned long zero_bytemask(unsigned long data)
{
        return ~1UL << data;
}

/*
 * 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 data;

        asm_inline volatile(
                "0:     lg      %[data],0(%[addr])\n"
                "1:     nopr    %%r7\n"
                EX_TABLE_ZEROPAD(0b, 1b, %[data], %[addr])
                EX_TABLE_ZEROPAD(1b, 1b, %[data], %[addr])
                : [data] "=d" (data)
                : [addr] "a" (addr), "m" (*(unsigned long *)addr));
        return data;
}

#endif /* _ASM_WORD_AT_A_TIME_H */