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 (2138B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2/*
      3 * Copyright (C) 2008 Michal Simek
      4 * Copyright (C) 2007 John Williams
      5 * Copyright (C) 2006 Atmark Techno, Inc.
      6 */
      7
      8#ifndef _ASM_MICROBLAZE_DELAY_H
      9#define _ASM_MICROBLAZE_DELAY_H
     10
     11#include <linux/param.h>
     12
     13static inline void __delay(unsigned long loops)
     14{
     15	asm volatile ("# __delay		\n\t"		\
     16			"1: addi	%0, %0, -1\t\n"		\
     17			"bneid	%0, 1b		\t\n"		\
     18			"nop			\t\n"
     19			: "=r" (loops)
     20			: "0" (loops));
     21}
     22
     23/*
     24 * Note that 19 * 226 == 4294 ==~ 2^32 / 10^6, so
     25 * loops = (4294 * usecs * loops_per_jiffy * HZ) / 2^32.
     26 *
     27 * The mul instruction gives us loops = (a * b) / 2^32.
     28 * We choose a = usecs * 19 * HZ and b = loops_per_jiffy * 226
     29 * because this lets us support a wide range of HZ and
     30 * loops_per_jiffy values without either a or b overflowing 2^32.
     31 * Thus we need usecs * HZ <= (2^32 - 1) / 19 = 226050910 and
     32 * loops_per_jiffy <= (2^32 - 1) / 226 = 19004280
     33 * (which corresponds to ~3800 bogomips at HZ = 100).
     34 * -- paulus
     35 */
     36#define __MAX_UDELAY	(226050910UL/HZ)	/* maximum udelay argument */
     37#define __MAX_NDELAY	(4294967295UL/HZ)	/* maximum ndelay argument */
     38
     39extern unsigned long loops_per_jiffy;
     40
     41static inline void __udelay(unsigned int x)
     42{
     43
     44	unsigned long long tmp =
     45		(unsigned long long)x * (unsigned long long)loops_per_jiffy \
     46			* 226LL;
     47	unsigned loops = tmp >> 32;
     48
     49/*
     50	__asm__("mulxuu %0,%1,%2" : "=r" (loops) :
     51		"r" (x), "r" (loops_per_jiffy * 226));
     52*/
     53	__delay(loops);
     54}
     55
     56extern void __bad_udelay(void);		/* deliberately undefined */
     57extern void __bad_ndelay(void);		/* deliberately undefined */
     58
     59#define udelay(n)						\
     60	({							\
     61		if (__builtin_constant_p(n)) {			\
     62			if ((n) / __MAX_UDELAY >= 1)		\
     63				__bad_udelay();			\
     64			else					\
     65				__udelay((n) * (19 * HZ));	\
     66		} else {					\
     67			__udelay((n) * (19 * HZ));		\
     68		}						\
     69	})
     70
     71#define ndelay(n)						\
     72	({							\
     73		if (__builtin_constant_p(n)) {			\
     74			if ((n) / __MAX_NDELAY >= 1)		\
     75				__bad_ndelay();			\
     76			else					\
     77				__udelay((n) * HZ);		\
     78		} else {					\
     79			__udelay((n) * HZ);			\
     80		}						\
     81	})
     82
     83#define muldiv(a, b, c)		(((a)*(b))/(c))
     84
     85#endif /* _ASM_MICROBLAZE_DELAY_H */