Nicolas Pitre | d73cd42 | 2008-09-15 16:44:55 -0400 | [diff] [blame] | 1 | /* |
| 2 | * arch/arm/mm/highmem.c -- ARM highmem support |
| 3 | * |
| 4 | * Author: Nicolas Pitre |
| 5 | * Created: september 8, 2008 |
| 6 | * Copyright: Marvell Semiconductors Inc. |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU General Public License version 2 as |
| 10 | * published by the Free Software Foundation. |
| 11 | */ |
| 12 | |
| 13 | #include <linux/module.h> |
| 14 | #include <linux/highmem.h> |
| 15 | #include <linux/interrupt.h> |
| 16 | #include <asm/fixmap.h> |
| 17 | #include <asm/cacheflush.h> |
| 18 | #include <asm/tlbflush.h> |
| 19 | #include "mm.h" |
| 20 | |
| 21 | void *kmap(struct page *page) |
| 22 | { |
| 23 | might_sleep(); |
| 24 | if (!PageHighMem(page)) |
| 25 | return page_address(page); |
| 26 | return kmap_high(page); |
| 27 | } |
| 28 | EXPORT_SYMBOL(kmap); |
| 29 | |
| 30 | void kunmap(struct page *page) |
| 31 | { |
| 32 | BUG_ON(in_interrupt()); |
| 33 | if (!PageHighMem(page)) |
| 34 | return; |
| 35 | kunmap_high(page); |
| 36 | } |
| 37 | EXPORT_SYMBOL(kunmap); |
| 38 | |
| 39 | void *kmap_atomic(struct page *page, enum km_type type) |
| 40 | { |
| 41 | unsigned int idx; |
| 42 | unsigned long vaddr; |
| 43 | |
| 44 | pagefault_disable(); |
| 45 | if (!PageHighMem(page)) |
| 46 | return page_address(page); |
| 47 | |
| 48 | idx = type + KM_TYPE_NR * smp_processor_id(); |
| 49 | vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); |
| 50 | #ifdef CONFIG_DEBUG_HIGHMEM |
| 51 | /* |
| 52 | * With debugging enabled, kunmap_atomic forces that entry to 0. |
| 53 | * Make sure it was indeed properly unmapped. |
| 54 | */ |
| 55 | BUG_ON(!pte_none(*(TOP_PTE(vaddr)))); |
| 56 | #endif |
| 57 | set_pte_ext(TOP_PTE(vaddr), mk_pte(page, kmap_prot), 0); |
| 58 | /* |
| 59 | * When debugging is off, kunmap_atomic leaves the previous mapping |
| 60 | * in place, so this TLB flush ensures the TLB is updated with the |
| 61 | * new mapping. |
| 62 | */ |
| 63 | local_flush_tlb_kernel_page(vaddr); |
| 64 | |
| 65 | return (void *)vaddr; |
| 66 | } |
| 67 | EXPORT_SYMBOL(kmap_atomic); |
| 68 | |
| 69 | void kunmap_atomic(void *kvaddr, enum km_type type) |
| 70 | { |
| 71 | unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; |
| 72 | unsigned int idx = type + KM_TYPE_NR * smp_processor_id(); |
| 73 | |
| 74 | if (kvaddr >= (void *)FIXADDR_START) { |
| 75 | __cpuc_flush_dcache_page((void *)vaddr); |
| 76 | #ifdef CONFIG_DEBUG_HIGHMEM |
| 77 | BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx)); |
| 78 | set_pte_ext(TOP_PTE(vaddr), __pte(0), 0); |
| 79 | local_flush_tlb_kernel_page(vaddr); |
| 80 | #else |
| 81 | (void) idx; /* to kill a warning */ |
| 82 | #endif |
| 83 | } |
| 84 | pagefault_enable(); |
| 85 | } |
| 86 | EXPORT_SYMBOL(kunmap_atomic); |
| 87 | |
| 88 | void *kmap_atomic_pfn(unsigned long pfn, enum km_type type) |
| 89 | { |
| 90 | unsigned int idx; |
| 91 | unsigned long vaddr; |
| 92 | |
| 93 | pagefault_disable(); |
| 94 | |
| 95 | idx = type + KM_TYPE_NR * smp_processor_id(); |
| 96 | vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); |
| 97 | #ifdef CONFIG_DEBUG_HIGHMEM |
| 98 | BUG_ON(!pte_none(*(TOP_PTE(vaddr)))); |
| 99 | #endif |
| 100 | set_pte_ext(TOP_PTE(vaddr), pfn_pte(pfn, kmap_prot), 0); |
| 101 | local_flush_tlb_kernel_page(vaddr); |
| 102 | |
| 103 | return (void *)vaddr; |
| 104 | } |
| 105 | |
| 106 | struct page *kmap_atomic_to_page(const void *ptr) |
| 107 | { |
| 108 | unsigned long vaddr = (unsigned long)ptr; |
| 109 | pte_t *pte; |
| 110 | |
| 111 | if (vaddr < FIXADDR_START) |
| 112 | return virt_to_page(ptr); |
| 113 | |
| 114 | pte = TOP_PTE(vaddr); |
| 115 | return pte_page(*pte); |
| 116 | } |