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.h (2488B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2#ifndef _LINUX_DELAY_H
      3#define _LINUX_DELAY_H
      4
      5/*
      6 * Copyright (C) 1993 Linus Torvalds
      7 *
      8 * Delay routines, using a pre-computed "loops_per_jiffy" value.
      9 *
     10 * Please note that ndelay(), udelay() and mdelay() may return early for
     11 * several reasons:
     12 *  1. computed loops_per_jiffy too low (due to the time taken to
     13 *     execute the timer interrupt.)
     14 *  2. cache behaviour affecting the time it takes to execute the
     15 *     loop function.
     16 *  3. CPU clock rate changes.
     17 *
     18 * Please see this thread:
     19 *   https://lists.openwall.net/linux-kernel/2011/01/09/56
     20 */
     21
     22#include <linux/math.h>
     23#include <linux/sched.h>
     24
     25extern unsigned long loops_per_jiffy;
     26
     27#include <asm/delay.h>
     28
     29/*
     30 * Using udelay() for intervals greater than a few milliseconds can
     31 * risk overflow for high loops_per_jiffy (high bogomips) machines. The
     32 * mdelay() provides a wrapper to prevent this.  For delays greater
     33 * than MAX_UDELAY_MS milliseconds, the wrapper is used.  Architecture
     34 * specific values can be defined in asm-???/delay.h as an override.
     35 * The 2nd mdelay() definition ensures GCC will optimize away the 
     36 * while loop for the common cases where n <= MAX_UDELAY_MS  --  Paul G.
     37 */
     38
     39#ifndef MAX_UDELAY_MS
     40#define MAX_UDELAY_MS	5
     41#endif
     42
     43#ifndef mdelay
     44#define mdelay(n) (\
     45	(__builtin_constant_p(n) && (n)<=MAX_UDELAY_MS) ? udelay((n)*1000) : \
     46	({unsigned long __ms=(n); while (__ms--) udelay(1000);}))
     47#endif
     48
     49#ifndef ndelay
     50static inline void ndelay(unsigned long x)
     51{
     52	udelay(DIV_ROUND_UP(x, 1000));
     53}
     54#define ndelay(x) ndelay(x)
     55#endif
     56
     57extern unsigned long lpj_fine;
     58void calibrate_delay(void);
     59void __attribute__((weak)) calibration_delay_done(void);
     60void msleep(unsigned int msecs);
     61unsigned long msleep_interruptible(unsigned int msecs);
     62void usleep_range_state(unsigned long min, unsigned long max,
     63			unsigned int state);
     64
     65static inline void usleep_range(unsigned long min, unsigned long max)
     66{
     67	usleep_range_state(min, max, TASK_UNINTERRUPTIBLE);
     68}
     69
     70static inline void usleep_idle_range(unsigned long min, unsigned long max)
     71{
     72	usleep_range_state(min, max, TASK_IDLE);
     73}
     74
     75static inline void ssleep(unsigned int seconds)
     76{
     77	msleep(seconds * 1000);
     78}
     79
     80/* see Documentation/timers/timers-howto.rst for the thresholds */
     81static inline void fsleep(unsigned long usecs)
     82{
     83	if (usecs <= 10)
     84		udelay(usecs);
     85	else if (usecs <= 20000)
     86		usleep_range(usecs, 2 * usecs);
     87	else
     88		msleep(DIV_ROUND_UP(usecs, 1000));
     89}
     90
     91#endif /* defined(_LINUX_DELAY_H) */