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- /*
- * 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 <linux/kernel.h>
- #include <linux/threads.h>
- #include <asm/page.h>
- #ifdef CONFIG_HIGHMEM
- #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 P3 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 {
- /*
- * The FIX_CMAP entries are used by kmap_coherent() to get virtual
- * addresses which are of a known color, and so their values are
- * important. __fix_to_virt(FIX_CMAP_END - n) must give an address
- * which is the same color as a page (n<<PAGE_SHIFT).
- */
- #define FIX_N_COLOURS 8
- FIX_CMAP_BEGIN,
- FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * NR_CPUS) - 1,
- #ifdef CONFIG_HIGHMEM
- FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
- FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * NR_CPUS) - 1,
- #endif
- #ifdef CONFIG_IOREMAP_FIXED
- /*
- * FIX_IOREMAP entries are useful for mapping physical address
- * space before ioremap() is useable, e.g. really early in boot
- * before kmalloc() is working.
- */
- #define FIX_N_IOREMAPS 32
- FIX_IOREMAP_BEGIN,
- FIX_IOREMAP_END = FIX_IOREMAP_BEGIN + FIX_N_IOREMAPS - 1,
- #endif
- __end_of_fixed_addresses
- };
- extern void __set_fixmap(enum fixed_addresses idx,
- unsigned long phys, pgprot_t flags);
- extern void __clear_fixmap(enum fixed_addresses idx, pgprot_t flags);
- #define set_fixmap(idx, phys) \
- __set_fixmap(idx, phys, PAGE_KERNEL)
- /*
- * Some hardware wants to get fixmapped without caching.
- */
- #define set_fixmap_nocache(idx, phys) \
- __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
- /*
- * 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..
- */
- #ifdef CONFIG_SUPERH32
- #define FIXADDR_TOP (P4SEG - PAGE_SIZE)
- #else
- #define FIXADDR_TOP (0xff000000 - PAGE_SIZE)
- #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);
- }
- #endif
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