mirror of
https://github.com/torvalds/linux.git
synced 2024-12-18 00:53:40 +00:00
119 lines
3.4 KiB
C
119 lines
3.4 KiB
C
/*
|
|
* fixmap.h: compile-time virtual memory allocation
|
|
*
|
|
* This file is subject to the terms and conditions of the GNU General Public
|
|
* License. See the file "COPYING" in the main directory of this archive
|
|
* for more details.
|
|
*
|
|
* Copyright (C) 1998 Ingo Molnar
|
|
*
|
|
* Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
|
|
*/
|
|
|
|
#ifndef _ASM_FIXMAP_H
|
|
#define _ASM_FIXMAP_H
|
|
|
|
#include <asm/page.h>
|
|
#ifdef CONFIG_HIGHMEM
|
|
#include <linux/threads.h>
|
|
#include <asm/kmap_types.h>
|
|
#endif
|
|
|
|
/*
|
|
* Here we define all the compile-time 'special' virtual
|
|
* addresses. The point is to have a constant address at
|
|
* compile time, but to set the physical address only
|
|
* in the boot process. We allocate these special addresses
|
|
* from the end of virtual memory (0xfffff000) backwards.
|
|
* Also this lets us do fail-safe vmalloc(), we
|
|
* can guarantee that these special addresses and
|
|
* vmalloc()-ed addresses never overlap.
|
|
*
|
|
* these 'compile-time allocated' memory buffers are
|
|
* fixed-size 4k pages. (or larger if used with an increment
|
|
* highger than 1) use fixmap_set(idx,phys) to associate
|
|
* physical memory with fixmap indices.
|
|
*
|
|
* TLB entries of such buffers will not be flushed across
|
|
* task switches.
|
|
*/
|
|
|
|
/*
|
|
* on UP currently we will have no trace of the fixmap mechanizm,
|
|
* no page table allocations, etc. This might change in the
|
|
* future, say framebuffers for the console driver(s) could be
|
|
* fix-mapped?
|
|
*/
|
|
enum fixed_addresses {
|
|
#define FIX_N_COLOURS 8
|
|
FIX_CMAP_BEGIN,
|
|
#ifdef CONFIG_MIPS_MT_SMTC
|
|
FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * NR_CPUS),
|
|
#else
|
|
FIX_CMAP_END = FIX_CMAP_BEGIN + FIX_N_COLOURS,
|
|
#endif
|
|
#ifdef CONFIG_HIGHMEM
|
|
/* reserved pte's for temporary kernel mappings */
|
|
FIX_KMAP_BEGIN = FIX_CMAP_END + 1,
|
|
FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
|
|
#endif
|
|
__end_of_fixed_addresses
|
|
};
|
|
|
|
/*
|
|
* used by vmalloc.c.
|
|
*
|
|
* Leave one empty page between vmalloc'ed areas and
|
|
* the start of the fixmap, and leave one page empty
|
|
* at the top of mem..
|
|
*/
|
|
#if defined(CONFIG_CPU_TX39XX) || defined(CONFIG_CPU_TX49XX)
|
|
#define FIXADDR_TOP ((unsigned long)(long)(int)(0xff000000 - 0x20000))
|
|
#else
|
|
#define FIXADDR_TOP ((unsigned long)(long)(int)0xfffe0000)
|
|
#endif
|
|
#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
|
|
#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
|
|
|
|
#define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
|
|
#define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
|
|
|
|
extern void __this_fixmap_does_not_exist(void);
|
|
|
|
/*
|
|
* 'index to address' translation. If anyone tries to use the idx
|
|
* directly without tranlation, we catch the bug with a NULL-deference
|
|
* kernel oops. Illegal ranges of incoming indices are caught too.
|
|
*/
|
|
static inline unsigned long fix_to_virt(const unsigned int idx)
|
|
{
|
|
/*
|
|
* this branch gets completely eliminated after inlining,
|
|
* except when someone tries to use fixaddr indices in an
|
|
* illegal way. (such as mixing up address types or using
|
|
* out-of-range indices).
|
|
*
|
|
* If it doesn't get removed, the linker will complain
|
|
* loudly with a reasonably clear error message..
|
|
*/
|
|
if (idx >= __end_of_fixed_addresses)
|
|
__this_fixmap_does_not_exist();
|
|
|
|
return __fix_to_virt(idx);
|
|
}
|
|
|
|
static inline unsigned long virt_to_fix(const unsigned long vaddr)
|
|
{
|
|
BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
|
|
return __virt_to_fix(vaddr);
|
|
}
|
|
|
|
/*
|
|
* Called from pgtable_init()
|
|
*/
|
|
extern void fixrange_init(unsigned long start, unsigned long end,
|
|
pgd_t *pgd_base);
|
|
|
|
|
|
#endif
|