/* * 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); /* * 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 ((unsigned long)(-PAGE_SIZE)) #endif #define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) #define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NOCACHE #include <asm-generic/fixmap.h> #endif