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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fixmap.h (2596B)

      1/* SPDX-License-Identifier: GPL-2.0-or-later */
      2/*
      3 * OpenRISC Linux
      4 *
      5 * Linux architectural port borrowing liberally from similar works of
      6 * others.  All original copyrights apply as per the original source
      7 * declaration.
      8 *
      9 * OpenRISC implementation:
     10 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
     11 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
     12 * et al.
     13 */
     14
     15#ifndef __ASM_OPENRISC_FIXMAP_H
     16#define __ASM_OPENRISC_FIXMAP_H
     17
     18/* Why exactly do we need 2 empty pages between the top of the fixed
     19 * addresses and the top of virtual memory?  Something is using that
     20 * memory space but not sure what right now... If you find it, leave
     21 * a comment here.
     22 */
     23#define FIXADDR_TOP	((unsigned long) (-2*PAGE_SIZE))
     24
     25#include <linux/kernel.h>
     26#include <linux/bug.h>
     27#include <asm/page.h>
     28
     29/*
     30 * On OpenRISC we use these special fixed_addresses for doing ioremap
     31 * early in the boot process before memory initialization is complete.
     32 * This is used, in particular, by the early serial console code.
     33 *
     34 * It's not really 'fixmap', per se, but fits loosely into the same
     35 * paradigm.
     36 */
     37enum fixed_addresses {
     38	/*
     39	 * FIX_IOREMAP entries are useful for mapping physical address
     40	 * space before ioremap() is useable, e.g. really early in boot
     41	 * before kmalloc() is working.
     42	 */
     43#define FIX_N_IOREMAPS  32
     44	FIX_IOREMAP_BEGIN,
     45	FIX_IOREMAP_END = FIX_IOREMAP_BEGIN + FIX_N_IOREMAPS - 1,
     46	__end_of_fixed_addresses
     47};
     48
     49#define FIXADDR_SIZE		(__end_of_fixed_addresses << PAGE_SHIFT)
     50/* FIXADDR_BOTTOM might be a better name here... */
     51#define FIXADDR_START		(FIXADDR_TOP - FIXADDR_SIZE)
     52
     53#define __fix_to_virt(x)	(FIXADDR_TOP - ((x) << PAGE_SHIFT))
     54#define __virt_to_fix(x)	((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
     55
     56/*
     57 * 'index to address' translation. If anyone tries to use the idx
     58 * directly without tranlation, we catch the bug with a NULL-deference
     59 * kernel oops. Illegal ranges of incoming indices are caught too.
     60 */
     61static __always_inline unsigned long fix_to_virt(const unsigned int idx)
     62{
     63	/*
     64	 * this branch gets completely eliminated after inlining,
     65	 * except when someone tries to use fixaddr indices in an
     66	 * illegal way. (such as mixing up address types or using
     67	 * out-of-range indices).
     68	 *
     69	 * If it doesn't get removed, the linker will complain
     70	 * loudly with a reasonably clear error message..
     71	 */
     72	if (idx >= __end_of_fixed_addresses)
     73		BUG();
     74
     75	return __fix_to_virt(idx);
     76}
     77
     78static inline unsigned long virt_to_fix(const unsigned long vaddr)
     79{
     80	BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
     81	return __virt_to_fix(vaddr);
     82}
     83
     84#endif