Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 | /*
* highmem.h: virtual kernel memory mappings for high memory
*
* PowerPC version, stolen from the i386 version.
*
* Used in CONFIG_HIGHMEM systems for memory pages which
* are not addressable by direct kernel virtual addresses.
*
* Copyright (C) 1999 Gerhard Wichert, Siemens AG
* Gerhard.Wichert@pdb.siemens.de
*
*
* Redesigned the x86 32-bit VM architecture to deal with
* up to 16 Terrabyte physical memory. With current x86 CPUs
* we now support up to 64 Gigabytes physical RAM.
*
* Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
*/
#ifndef _ASM_HIGHMEM_H
#define _ASM_HIGHMEM_H
#ifdef __KERNEL__
#include <linux/init.h>
#include <linux/interrupt.h>
#include <asm/kmap_types.h>
#include <asm/tlbflush.h>
#include <asm/page.h>
#include <asm/fixmap.h>
extern pte_t *kmap_pte;
extern pgprot_t kmap_prot;
extern pte_t *pkmap_page_table;
/*
* Right now we initialize only a single pte table. It can be extended
* easily, subsequent pte tables have to be allocated in one physical
* chunk of RAM.
*/
#define LAST_PKMAP (1 << PTE_SHIFT)
#define LAST_PKMAP_MASK (LAST_PKMAP-1)
#define PKMAP_BASE ((FIXADDR_START - PAGE_SIZE*(LAST_PKMAP + 1)) & PMD_MASK)
#define PKMAP_NR(virt) ((virt-PKMAP_BASE) >> PAGE_SHIFT)
#define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))
extern void *kmap_high(struct page *page);
extern void kunmap_high(struct page *page);
static inline void *kmap(struct page *page)
{
might_sleep();
if (!PageHighMem(page))
return page_address(page);
return kmap_high(page);
}
static inline void kunmap(struct page *page)
{
BUG_ON(in_interrupt());
if (!PageHighMem(page))
return;
kunmap_high(page);
}
/*
* The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
* gives a more generic (and caching) interface. But kmap_atomic can
* be used in IRQ contexts, so in some (very limited) cases we need
* it.
*/
static inline void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot)
{
unsigned int idx;
unsigned long vaddr;
/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
pagefault_disable();
if (!PageHighMem(page))
return page_address(page);
idx = type + KM_TYPE_NR*smp_processor_id();
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
#ifdef CONFIG_DEBUG_HIGHMEM
BUG_ON(!pte_none(*(kmap_pte-idx)));
#endif
__set_pte_at(&init_mm, vaddr, kmap_pte-idx, mk_pte(page, prot));
flush_tlb_page(NULL, vaddr);
return (void*) vaddr;
}
static inline void *kmap_atomic(struct page *page, enum km_type type)
{
return kmap_atomic_prot(page, type, kmap_prot);
}
static inline void kunmap_atomic(void *kvaddr, enum km_type type)
{
#ifdef CONFIG_DEBUG_HIGHMEM
unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id();
if (vaddr < __fix_to_virt(FIX_KMAP_END)) {
pagefault_enable();
return;
}
BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
/*
* force other mappings to Oops if they'll try to access
* this pte without first remap it
*/
pte_clear(&init_mm, vaddr, kmap_pte-idx);
flush_tlb_page(NULL, vaddr);
#endif
pagefault_enable();
}
static inline struct page *kmap_atomic_to_page(void *ptr)
{
unsigned long idx, vaddr = (unsigned long) ptr;
pte_t *pte;
if (vaddr < FIXADDR_START)
return virt_to_page(ptr);
idx = virt_to_fix(vaddr);
pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
return pte_page(*pte);
}
#define flush_cache_kmaps() flush_cache_all()
#endif /* __KERNEL__ */
#endif /* _ASM_HIGHMEM_H */
|