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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delay.c (1045B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
      4 */
      5#include <linux/delay.h>
      6#include <linux/export.h>
      7#include <linux/smp.h>
      8#include <linux/timex.h>
      9
     10#include <asm/compiler.h>
     11#include <asm/processor.h>
     12
     13void __delay(unsigned long cycles)
     14{
     15	u64 t0 = get_cycles();
     16
     17	while ((unsigned long)(get_cycles() - t0) < cycles)
     18		cpu_relax();
     19}
     20EXPORT_SYMBOL(__delay);
     21
     22/*
     23 * Division by multiplication: you don't have to worry about
     24 * loss of precision.
     25 *
     26 * Use only for very small delays ( < 1 msec).	Should probably use a
     27 * lookup table, really, as the multiplications take much too long with
     28 * short delays.  This is a "reasonable" implementation, though (and the
     29 * first constant multiplications gets optimized away if the delay is
     30 * a constant)
     31 */
     32
     33void __udelay(unsigned long us)
     34{
     35	__delay((us * 0x000010c7ull * HZ * lpj_fine) >> 32);
     36}
     37EXPORT_SYMBOL(__udelay);
     38
     39void __ndelay(unsigned long ns)
     40{
     41	__delay((ns * 0x00000005ull * HZ * lpj_fine) >> 32);
     42}
     43EXPORT_SYMBOL(__ndelay);