cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

delay.c (1571B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Delay loops based on the OpenRISC implementation.
      4 *
      5 * Copyright (C) 2012 ARM Limited
      6 *
      7 * Author: Will Deacon <will.deacon@arm.com>
      8 */
      9
     10#include <linux/delay.h>
     11#include <linux/init.h>
     12#include <linux/kernel.h>
     13#include <linux/module.h>
     14#include <linux/timex.h>
     15
     16#include <clocksource/arm_arch_timer.h>
     17
     18#define USECS_TO_CYCLES(time_usecs)			\
     19	xloops_to_cycles((time_usecs) * 0x10C7UL)
     20
     21static inline unsigned long xloops_to_cycles(unsigned long xloops)
     22{
     23	return (xloops * loops_per_jiffy * HZ) >> 32;
     24}
     25
     26void __delay(unsigned long cycles)
     27{
     28	cycles_t start = get_cycles();
     29
     30	if (cpus_have_const_cap(ARM64_HAS_WFXT)) {
     31		u64 end = start + cycles;
     32
     33		/*
     34		 * Start with WFIT. If an interrupt makes us resume
     35		 * early, use a WFET loop to complete the delay.
     36		 */
     37		wfit(end);
     38		while ((get_cycles() - start) < cycles)
     39			wfet(end);
     40	} else 	if (arch_timer_evtstrm_available()) {
     41		const cycles_t timer_evt_period =
     42			USECS_TO_CYCLES(ARCH_TIMER_EVT_STREAM_PERIOD_US);
     43
     44		while ((get_cycles() - start + timer_evt_period) < cycles)
     45			wfe();
     46	}
     47
     48	while ((get_cycles() - start) < cycles)
     49		cpu_relax();
     50}
     51EXPORT_SYMBOL(__delay);
     52
     53inline void __const_udelay(unsigned long xloops)
     54{
     55	__delay(xloops_to_cycles(xloops));
     56}
     57EXPORT_SYMBOL(__const_udelay);
     58
     59void __udelay(unsigned long usecs)
     60{
     61	__const_udelay(usecs * 0x10C7UL); /* 2**32 / 1000000 (rounded up) */
     62}
     63EXPORT_SYMBOL(__udelay);
     64
     65void __ndelay(unsigned long nsecs)
     66{
     67	__const_udelay(nsecs * 0x5UL); /* 2**32 / 1000000000 (rounded up) */
     68}
     69EXPORT_SYMBOL(__ndelay);