1 /* MN10300 Virtual kernel memory mappings for high memory 2 * 3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. 4 * Written by David Howells (dhowells@redhat.com) 5 * - Derived from include/asm-i386/highmem.h 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public Licence 9 * as published by the Free Software Foundation; either version 10 * 2 of the Licence, or (at your option) any later version. 11 */ 12 #ifndef _ASM_HIGHMEM_H 13 #define _ASM_HIGHMEM_H 14 15 #ifdef __KERNEL__ 16 17 #include <linux/init.h> 18 #include <linux/interrupt.h> 19 #include <linux/highmem.h> 20 #include <asm/kmap_types.h> 21 #include <asm/pgtable.h> 22 23 /* undef for production */ 24 #undef HIGHMEM_DEBUG 25 26 /* declarations for highmem.c */ 27 extern unsigned long highstart_pfn, highend_pfn; 28 29 extern pte_t *kmap_pte; 30 extern pgprot_t kmap_prot; 31 extern pte_t *pkmap_page_table; 32 33 extern void __init kmap_init(void); 34 35 /* 36 * Right now we initialize only a single pte table. It can be extended 37 * easily, subsequent pte tables have to be allocated in one physical 38 * chunk of RAM. 39 */ 40 #define PKMAP_BASE 0xfe000000UL 41 #define LAST_PKMAP 1024 42 #define LAST_PKMAP_MASK (LAST_PKMAP - 1) 43 #define PKMAP_NR(virt) ((virt - PKMAP_BASE) >> PAGE_SHIFT) 44 #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT)) 45 46 extern unsigned long kmap_high(struct page *page); 47 extern void kunmap_high(struct page *page); 48 kmap(struct page * page)49static inline unsigned long kmap(struct page *page) 50 { 51 if (in_interrupt()) 52 BUG(); 53 if (page < highmem_start_page) 54 return page_address(page); 55 return kmap_high(page); 56 } 57 kunmap(struct page * page)58static inline void kunmap(struct page *page) 59 { 60 if (in_interrupt()) 61 BUG(); 62 if (page < highmem_start_page) 63 return; 64 kunmap_high(page); 65 } 66 67 /* 68 * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap 69 * gives a more generic (and caching) interface. But kmap_atomic can 70 * be used in IRQ contexts, so in some (very limited) cases we need 71 * it. 72 */ kmap_atomic(struct page * page)73static inline void *kmap_atomic(struct page *page) 74 { 75 unsigned long vaddr; 76 int idx, type; 77 78 preempt_disable(); 79 pagefault_disable(); 80 if (page < highmem_start_page) 81 return page_address(page); 82 83 type = kmap_atomic_idx_push(); 84 idx = type + KM_TYPE_NR * smp_processor_id(); 85 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); 86 #if HIGHMEM_DEBUG 87 if (!pte_none(*(kmap_pte - idx))) 88 BUG(); 89 #endif 90 set_pte(kmap_pte - idx, mk_pte(page, kmap_prot)); 91 local_flush_tlb_one(vaddr); 92 93 return (void *)vaddr; 94 } 95 __kunmap_atomic(unsigned long vaddr)96static inline void __kunmap_atomic(unsigned long vaddr) 97 { 98 int type; 99 100 if (vaddr < FIXADDR_START) { /* FIXME */ 101 pagefault_enable(); 102 preempt_enable(); 103 return; 104 } 105 106 type = kmap_atomic_idx(); 107 108 #if HIGHMEM_DEBUG 109 { 110 unsigned int idx; 111 idx = type + KM_TYPE_NR * smp_processor_id(); 112 113 if (vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx)) 114 BUG(); 115 116 /* 117 * force other mappings to Oops if they'll try to access 118 * this pte without first remap it 119 */ 120 pte_clear(kmap_pte - idx); 121 local_flush_tlb_one(vaddr); 122 } 123 #endif 124 125 kmap_atomic_idx_pop(); 126 pagefault_enable(); 127 preempt_enable(); 128 } 129 #endif /* __KERNEL__ */ 130 131 #endif /* _ASM_HIGHMEM_H */ 132