74 lines
1.5 KiB
C
74 lines
1.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
|
|
/*
|
|
* Copyright (C) 2013 ARM Ltd.
|
|
*/
|
|
#ifndef __ASM_WORD_AT_A_TIME_H
|
|
#define __ASM_WORD_AT_A_TIME_H
|
|
|
|
#include <linux/uaccess.h>
|
|
|
|
#ifndef __AARCH64EB__
|
|
|
|
#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)
|
|
{
|
|
return fls64(mask) >> 3;
|
|
}
|
|
|
|
#define zero_bytemask(mask) (mask)
|
|
|
|
#else /* __AARCH64EB__ */
|
|
#include <asm-generic/word-at-a-time.h>
|
|
#endif
|
|
|
|
/*
|
|
* 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;
|
|
|
|
__uaccess_enable_tco_async();
|
|
|
|
/* Load word from unaligned pointer addr */
|
|
asm(
|
|
"1: ldr %0, %2\n"
|
|
"2:\n"
|
|
_ASM_EXTABLE_LOAD_UNALIGNED_ZEROPAD(1b, 2b, %0, %1)
|
|
: "=&r" (ret)
|
|
: "r" (addr), "Q" (*(unsigned long *)addr));
|
|
|
|
__uaccess_disable_tco_async();
|
|
|
|
return ret;
|
|
}
|
|
|
|
#endif /* __ASM_WORD_AT_A_TIME_H */
|