cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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word-at-a-time.h (1566B)

      1/* SPDX-License-Identifier: GPL-2.0-only */
      2/*
      3 * Copyright (C) 2013 ARM Ltd.
      4 */
      5#ifndef __ASM_WORD_AT_A_TIME_H
      6#define __ASM_WORD_AT_A_TIME_H
      7
      8#include <linux/uaccess.h>
      9
     10#ifndef __AARCH64EB__
     11
     12#include <linux/kernel.h>
     13
     14struct word_at_a_time {
     15	const unsigned long one_bits, high_bits;
     16};
     17
     18#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
     19
     20static inline unsigned long has_zero(unsigned long a, unsigned long *bits,
     21				     const struct word_at_a_time *c)
     22{
     23	unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
     24	*bits = mask;
     25	return mask;
     26}
     27
     28#define prep_zero_mask(a, bits, c) (bits)
     29
     30static inline unsigned long create_zero_mask(unsigned long bits)
     31{
     32	bits = (bits - 1) & ~bits;
     33	return bits >> 7;
     34}
     35
     36static inline unsigned long find_zero(unsigned long mask)
     37{
     38	return fls64(mask) >> 3;
     39}
     40
     41#define zero_bytemask(mask) (mask)
     42
     43#else	/* __AARCH64EB__ */
     44#include <asm-generic/word-at-a-time.h>
     45#endif
     46
     47/*
     48 * Load an unaligned word from kernel space.
     49 *
     50 * In the (very unlikely) case of the word being a page-crosser
     51 * and the next page not being mapped, take the exception and
     52 * return zeroes in the non-existing part.
     53 */
     54static inline unsigned long load_unaligned_zeropad(const void *addr)
     55{
     56	unsigned long ret;
     57
     58	__uaccess_enable_tco_async();
     59
     60	/* Load word from unaligned pointer addr */
     61	asm(
     62	"1:	ldr	%0, %2\n"
     63	"2:\n"
     64	_ASM_EXTABLE_LOAD_UNALIGNED_ZEROPAD(1b, 2b, %0, %1)
     65	: "=&r" (ret)
     66	: "r" (addr), "Q" (*(unsigned long *)addr));
     67
     68	__uaccess_disable_tco_async();
     69
     70	return ret;
     71}
     72
     73#endif /* __ASM_WORD_AT_A_TIME_H */