1 /* 2 * Fixmap support for Hexagon - enough to support highmem features 3 * 4 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 and 8 * only version 2 as published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 18 * 02110-1301, USA. 19 */ 20 21 #ifndef _ASM_FIXMAP_H 22 #define _ASM_FIXMAP_H 23 24 /* 25 * A lot of the fixmap info is already in mem-layout.h 26 */ 27 #include <asm/mem-layout.h> 28 29 /* 30 * Full fixmap support involves set_fixmap() functions, but 31 * these may not be needed if all we're after is an area for 32 * highmem kernel mappings. 33 */ 34 #define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT)) 35 #define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT) 36 37 extern void __this_fixmap_does_not_exist(void); 38 39 /** 40 * fix_to_virt -- "index to address" translation. 41 * 42 * If anyone tries to use the idx directly without translation, 43 * we catch the bug with a NULL-deference kernel oops. Illegal 44 * ranges of incoming indices are caught too. 45 */ 46 static inline unsigned long fix_to_virt(const unsigned int idx) 47 { 48 /* 49 * This branch gets completely eliminated after inlining, 50 * except when someone tries to use fixaddr indices in an 51 * illegal way. (such as mixing up address types or using 52 * out-of-range indices). 53 * 54 * If it doesn't get removed, the linker will complain 55 * loudly with a reasonably clear error message.. 56 */ 57 if (idx >= __end_of_fixed_addresses) 58 __this_fixmap_does_not_exist(); 59 60 return __fix_to_virt(idx); 61 } 62 63 static inline unsigned long virt_to_fix(const unsigned long vaddr) 64 { 65 BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START); 66 return __virt_to_fix(vaddr); 67 } 68 69 #define kmap_get_fixmap_pte(vaddr) \ 70 pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), \ 71 (vaddr)), (vaddr)), (vaddr)) 72 73 #endif 74