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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __ASM_ARM_WORD_AT_A_TIME_H
#define __ASM_ARM_WORD_AT_A_TIME_H
#ifndef __ARMEB__
/*
* Little-endian word-at-a-time zero byte handling.
* Heavily based on the x86 algorithm.
*/
#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)
{
unsigned long ret;
#if __LINUX_ARM_ARCH__ >= 5
/* We have clz available. */
ret = fls(mask) >> 3;
#else
/* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */
ret = (0x0ff0001 + mask) >> 23;
/* Fix the 1 for 00 case */
ret &= mask;
#endif
return ret;
}
#define zero_bytemask(mask) (mask)
#else /* __ARMEB__ */
#include <asm-generic/word-at-a-time.h>
#endif
#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, offset;
/* Load word from unaligned pointer addr */
asm(
"1: ldr %0, [%2]\n"
"2:\n"
" .pushsection .text.fixup,\"ax\"\n"
" .align 2\n"
"3: and %1, %2, #0x3\n"
" bic %2, %2, #0x3\n"
" ldr %0, [%2]\n"
" lsl %1, %1, #0x3\n"
#ifndef __ARMEB__
" lsr %0, %0, %1\n"
#else
" lsl %0, %0, %1\n"
#endif
" b 2b\n"
" .popsection\n"
" .pushsection __ex_table,\"a\"\n"
" .align 3\n"
" .long 1b, 3b\n"
" .popsection"
: "=&r" (ret), "=&r" (offset)
: "r" (addr), "Qo" (*(unsigned long *)addr));
return ret;
}
#endif /* DCACHE_WORD_ACCESS */
#endif /* __ASM_ARM_WORD_AT_A_TIME_H */
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