16a0abce4SKuninori Morimoto /* SPDX-License-Identifier: GPL-2.0 2f15cbe6fSPaul Mundt * 36a0abce4SKuninori Morimoto * fixmap.h: compile-time virtual memory allocation 4f15cbe6fSPaul Mundt * 5f15cbe6fSPaul Mundt * Copyright (C) 1998 Ingo Molnar 6f15cbe6fSPaul Mundt * 7f15cbe6fSPaul Mundt * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999 8f15cbe6fSPaul Mundt */ 9f15cbe6fSPaul Mundt 10f15cbe6fSPaul Mundt #ifndef _ASM_FIXMAP_H 11f15cbe6fSPaul Mundt #define _ASM_FIXMAP_H 12f15cbe6fSPaul Mundt 13f15cbe6fSPaul Mundt #include <linux/kernel.h> 14f9e2bdfdSPaul Mundt #include <linux/threads.h> 15f15cbe6fSPaul Mundt #include <asm/page.h> 16f15cbe6fSPaul Mundt 17f15cbe6fSPaul Mundt /* 18f15cbe6fSPaul Mundt * Here we define all the compile-time 'special' virtual 19f15cbe6fSPaul Mundt * addresses. The point is to have a constant address at 20f15cbe6fSPaul Mundt * compile time, but to set the physical address only 21f15cbe6fSPaul Mundt * in the boot process. We allocate these special addresses 22f15cbe6fSPaul Mundt * from the end of P3 backwards. 23f15cbe6fSPaul Mundt * Also this lets us do fail-safe vmalloc(), we 24f15cbe6fSPaul Mundt * can guarantee that these special addresses and 25f15cbe6fSPaul Mundt * vmalloc()-ed addresses never overlap. 26f15cbe6fSPaul Mundt * 27f15cbe6fSPaul Mundt * these 'compile-time allocated' memory buffers are 28f15cbe6fSPaul Mundt * fixed-size 4k pages. (or larger if used with an increment 29f15cbe6fSPaul Mundt * highger than 1) use fixmap_set(idx,phys) to associate 30f15cbe6fSPaul Mundt * physical memory with fixmap indices. 31f15cbe6fSPaul Mundt * 32f15cbe6fSPaul Mundt * TLB entries of such buffers will not be flushed across 33f15cbe6fSPaul Mundt * task switches. 34f15cbe6fSPaul Mundt */ 35f15cbe6fSPaul Mundt 36f15cbe6fSPaul Mundt /* 37f15cbe6fSPaul Mundt * on UP currently we will have no trace of the fixmap mechanizm, 38f15cbe6fSPaul Mundt * no page table allocations, etc. This might change in the 39f15cbe6fSPaul Mundt * future, say framebuffers for the console driver(s) could be 40f15cbe6fSPaul Mundt * fix-mapped? 41f15cbe6fSPaul Mundt */ 42f15cbe6fSPaul Mundt enum fixed_addresses { 4339ac11c1SStuart Menefy /* 4439ac11c1SStuart Menefy * The FIX_CMAP entries are used by kmap_coherent() to get virtual 4539ac11c1SStuart Menefy * addresses which are of a known color, and so their values are 4639ac11c1SStuart Menefy * important. __fix_to_virt(FIX_CMAP_END - n) must give an address 4739ac11c1SStuart Menefy * which is the same color as a page (n<<PAGE_SHIFT). 4839ac11c1SStuart Menefy */ 49f9e2bdfdSPaul Mundt #define FIX_N_COLOURS 8 50f15cbe6fSPaul Mundt FIX_CMAP_BEGIN, 5139ac11c1SStuart Menefy FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * NR_CPUS) - 1, 522dc2f8e0SPaul Mundt 53a077e916SPaul Mundt #ifdef CONFIG_IOREMAP_FIXED 544d35b93aSMatt Fleming /* 554d35b93aSMatt Fleming * FIX_IOREMAP entries are useful for mapping physical address 564d35b93aSMatt Fleming * space before ioremap() is useable, e.g. really early in boot 574d35b93aSMatt Fleming * before kmalloc() is working. 584d35b93aSMatt Fleming */ 594d35b93aSMatt Fleming #define FIX_N_IOREMAPS 32 604d35b93aSMatt Fleming FIX_IOREMAP_BEGIN, 617210ed74SPaul Mundt FIX_IOREMAP_END = FIX_IOREMAP_BEGIN + FIX_N_IOREMAPS - 1, 62a077e916SPaul Mundt #endif 632dc2f8e0SPaul Mundt 64f15cbe6fSPaul Mundt __end_of_fixed_addresses 65f15cbe6fSPaul Mundt }; 66f15cbe6fSPaul Mundt 67f15cbe6fSPaul Mundt extern void __set_fixmap(enum fixed_addresses idx, 68f15cbe6fSPaul Mundt unsigned long phys, pgprot_t flags); 6907cad4dcSMatt Fleming extern void __clear_fixmap(enum fixed_addresses idx, pgprot_t flags); 70f15cbe6fSPaul Mundt 71f15cbe6fSPaul Mundt /* 72f15cbe6fSPaul Mundt * used by vmalloc.c. 73f15cbe6fSPaul Mundt * 74f15cbe6fSPaul Mundt * Leave one empty page between vmalloc'ed areas and 75f15cbe6fSPaul Mundt * the start of the fixmap, and leave one page empty 76f15cbe6fSPaul Mundt * at the top of mem.. 77f15cbe6fSPaul Mundt */ 78c3e0af98SPaul Mundt #define FIXADDR_TOP (P4SEG - PAGE_SIZE) 79f15cbe6fSPaul Mundt #define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) 80f15cbe6fSPaul Mundt #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) 81f15cbe6fSPaul Mundt 82083f7ba8SMark Salter #define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NOCACHE 83f15cbe6fSPaul Mundt 84083f7ba8SMark Salter #include <asm-generic/fixmap.h> 85f15cbe6fSPaul Mundt 86f15cbe6fSPaul Mundt #endif 87