2 * arch/arm/mm/highmem.c -- ARM highmem support
4 * Author: Nicolas Pitre
5 * Created: september 8, 2008
6 * Copyright: Marvell Semiconductors Inc.
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.
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>
21 void *kmap(struct page *page)
24 if (!PageHighMem(page))
25 return page_address(page);
26 return kmap_high(page);
30 void kunmap(struct page *page)
32 BUG_ON(in_interrupt());
33 if (!PageHighMem(page))
37 EXPORT_SYMBOL(kunmap);
39 void *kmap_atomic(struct page *page, enum km_type type)
46 if (!PageHighMem(page))
47 return page_address(page);
49 kmap = kmap_high_get(page);
53 idx = type + KM_TYPE_NR * smp_processor_id();
54 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
55 #ifdef CONFIG_DEBUG_HIGHMEM
57 * With debugging enabled, kunmap_atomic forces that entry to 0.
58 * Make sure it was indeed properly unmapped.
60 BUG_ON(!pte_none(*(TOP_PTE(vaddr))));
62 set_pte_ext(TOP_PTE(vaddr), mk_pte(page, kmap_prot), 0);
64 * When debugging is off, kunmap_atomic leaves the previous mapping
65 * in place, so this TLB flush ensures the TLB is updated with the
68 local_flush_tlb_kernel_page(vaddr);
72 EXPORT_SYMBOL(kmap_atomic);
74 void kunmap_atomic(void *kvaddr, enum km_type type)
76 unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
77 unsigned int idx = type + KM_TYPE_NR * smp_processor_id();
79 if (kvaddr >= (void *)FIXADDR_START) {
80 __cpuc_flush_dcache_page((void *)vaddr);
81 #ifdef CONFIG_DEBUG_HIGHMEM
82 BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
83 set_pte_ext(TOP_PTE(vaddr), __pte(0), 0);
84 local_flush_tlb_kernel_page(vaddr);
86 (void) idx; /* to kill a warning */
88 } else if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) {
89 /* this address was obtained through kmap_high_get() */
90 kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)]));
94 EXPORT_SYMBOL(kunmap_atomic);
96 void *kmap_atomic_pfn(unsigned long pfn, enum km_type type)
103 idx = type + KM_TYPE_NR * smp_processor_id();
104 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
105 #ifdef CONFIG_DEBUG_HIGHMEM
106 BUG_ON(!pte_none(*(TOP_PTE(vaddr))));
108 set_pte_ext(TOP_PTE(vaddr), pfn_pte(pfn, kmap_prot), 0);
109 local_flush_tlb_kernel_page(vaddr);
111 return (void *)vaddr;
114 struct page *kmap_atomic_to_page(const void *ptr)
116 unsigned long vaddr = (unsigned long)ptr;
119 if (vaddr < FIXADDR_START)
120 return virt_to_page(ptr);
122 pte = TOP_PTE(vaddr);
123 return pte_page(*pte);