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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xip.h (2556B)

      1/* SPDX-License-Identifier: GPL-2.0-only */
      2/*
      3 * MTD primitives for XIP support
      4 *
      5 * Author:	Nicolas Pitre
      6 * Created:	Nov 2, 2004
      7 * Copyright:	(C) 2004 MontaVista Software, Inc.
      8 *
      9 * This XIP support for MTD has been loosely inspired
     10 * by an earlier patch authored by David Woodhouse.
     11 */
     12
     13#ifndef __LINUX_MTD_XIP_H__
     14#define __LINUX_MTD_XIP_H__
     15
     16
     17#ifdef CONFIG_MTD_XIP
     18
     19/*
     20 * We really don't want gcc to guess anything.
     21 * We absolutely _need_ proper inlining.
     22 */
     23#include <linux/compiler.h>
     24
     25/*
     26 * Function that are modifying the flash state away from array mode must
     27 * obviously not be running from flash.  The __xipram is therefore marking
     28 * those functions so they get relocated to ram.
     29 */
     30#ifdef CONFIG_XIP_KERNEL
     31#define __xipram noinline __section(".xiptext")
     32#endif
     33
     34/*
     35 * Each architecture has to provide the following macros.  They must access
     36 * the hardware directly and not rely on any other (XIP) functions since they
     37 * won't be available when used (flash not in array mode).
     38 *
     39 * xip_irqpending()
     40 *
     41 * 	return non zero when any hardware interrupt is pending.
     42 *
     43 * xip_currtime()
     44 *
     45 * 	return a platform specific time reference to be used with
     46 * 	xip_elapsed_since().
     47 *
     48 * xip_elapsed_since(x)
     49 *
     50 * 	return in usecs the elapsed timebetween now and the reference x as
     51 * 	returned by xip_currtime().
     52 *
     53 * 	note 1: conversion to usec can be approximated, as long as the
     54 * 		returned value is <= the real elapsed time.
     55 * 	note 2: this should be able to cope with a few seconds without
     56 * 		overflowing.
     57 *
     58 * xip_iprefetch()
     59 *
     60 *      Macro to fill instruction prefetch
     61 *	e.g. a series of nops:  asm volatile (".rep 8; nop; .endr");
     62 */
     63
     64#include <asm/mtd-xip.h>
     65
     66#ifndef xip_irqpending
     67
     68#warning "missing IRQ and timer primitives for XIP MTD support"
     69#warning "some of the XIP MTD support code will be disabled"
     70#warning "your system will therefore be unresponsive when writing or erasing flash"
     71
     72#define xip_irqpending()	(0)
     73#define xip_currtime()		(0)
     74#define xip_elapsed_since(x)	(0)
     75
     76#endif
     77
     78#ifndef xip_iprefetch
     79#define xip_iprefetch()		do { } while (0)
     80#endif
     81
     82/*
     83 * xip_cpu_idle() is used when waiting for a delay equal or larger than
     84 * the system timer tick period.  This should put the CPU into idle mode
     85 * to save power and to be woken up only when some interrupts are pending.
     86 * This should not rely upon standard kernel code.
     87 */
     88#ifndef xip_cpu_idle
     89#define xip_cpu_idle()  do { } while (0)
     90#endif
     91
     92#endif /* CONFIG_MTD_XIP */
     93
     94#ifndef __xipram
     95#define __xipram
     96#endif
     97
     98#endif /* __LINUX_MTD_XIP_H__ */