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kernel add
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/*
* Copyright (C) 2013 ARM Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __ASM_WORD_AT_A_TIME_H
#define __ASM_WORD_AT_A_TIME_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, offset;
/* Load word from unaligned pointer addr */
asm(
"1: ldr %0, %3
"
"2:
"
" .pushsection .fixup,\"ax\"
"
" .align 2
"
"3: and %1, %2, #0x7
"
" bic %2, %2, #0x7
"
" ldr %0, [%2]
"
" lsl %1, %1, #0x3
"
#ifndef __AARCH64EB__
" lsr %0, %0, %1
"
#else
" lsl %0, %0, %1
"
#endif
" b 2b
"
" .popsection
"
" .pushsection __ex_table,\"a\"
"
" .align 3
"
" .quad 1b, 3b
"
" .popsection"
: "=&r" (ret), "=&r" (offset)
: "r" (addr), "Q" (*(unsigned long *)addr));
return ret;
}
#endif /* __ASM_WORD_AT_A_TIME_H */
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