1b8b572e1SStephen Rothwell /* 2b8b572e1SStephen Rothwell * highmem.h: virtual kernel memory mappings for high memory 3b8b572e1SStephen Rothwell * 4b8b572e1SStephen Rothwell * PowerPC version, stolen from the i386 version. 5b8b572e1SStephen Rothwell * 6b8b572e1SStephen Rothwell * Used in CONFIG_HIGHMEM systems for memory pages which 7b8b572e1SStephen Rothwell * are not addressable by direct kernel virtual addresses. 8b8b572e1SStephen Rothwell * 9b8b572e1SStephen Rothwell * Copyright (C) 1999 Gerhard Wichert, Siemens AG 10b8b572e1SStephen Rothwell * Gerhard.Wichert@pdb.siemens.de 11b8b572e1SStephen Rothwell * 12b8b572e1SStephen Rothwell * 13b8b572e1SStephen Rothwell * Redesigned the x86 32-bit VM architecture to deal with 14b8b572e1SStephen Rothwell * up to 16 Terrabyte physical memory. With current x86 CPUs 15b8b572e1SStephen Rothwell * we now support up to 64 Gigabytes physical RAM. 16b8b572e1SStephen Rothwell * 17b8b572e1SStephen Rothwell * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com> 18b8b572e1SStephen Rothwell */ 19b8b572e1SStephen Rothwell 20b8b572e1SStephen Rothwell #ifndef _ASM_HIGHMEM_H 21b8b572e1SStephen Rothwell #define _ASM_HIGHMEM_H 22b8b572e1SStephen Rothwell 23b8b572e1SStephen Rothwell #ifdef __KERNEL__ 24b8b572e1SStephen Rothwell 25b8b572e1SStephen Rothwell #include <linux/init.h> 26b8b572e1SStephen Rothwell #include <linux/interrupt.h> 27b8b572e1SStephen Rothwell #include <asm/kmap_types.h> 28b8b572e1SStephen Rothwell #include <asm/tlbflush.h> 29b8b572e1SStephen Rothwell #include <asm/page.h> 30b8b572e1SStephen Rothwell #include <asm/fixmap.h> 31b8b572e1SStephen Rothwell 32b8b572e1SStephen Rothwell extern pte_t *kmap_pte; 33b8b572e1SStephen Rothwell extern pgprot_t kmap_prot; 34b8b572e1SStephen Rothwell extern pte_t *pkmap_page_table; 35b8b572e1SStephen Rothwell 36b8b572e1SStephen Rothwell /* 37b8b572e1SStephen Rothwell * Right now we initialize only a single pte table. It can be extended 38b8b572e1SStephen Rothwell * easily, subsequent pte tables have to be allocated in one physical 39b8b572e1SStephen Rothwell * chunk of RAM. 40b8b572e1SStephen Rothwell */ 41b8b572e1SStephen Rothwell #define LAST_PKMAP (1 << PTE_SHIFT) 42b8b572e1SStephen Rothwell #define LAST_PKMAP_MASK (LAST_PKMAP-1) 43b8b572e1SStephen Rothwell #define PKMAP_BASE ((FIXADDR_START - PAGE_SIZE*(LAST_PKMAP + 1)) & PMD_MASK) 44b8b572e1SStephen Rothwell #define PKMAP_NR(virt) ((virt-PKMAP_BASE) >> PAGE_SHIFT) 45b8b572e1SStephen Rothwell #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT)) 46b8b572e1SStephen Rothwell 47b8b572e1SStephen Rothwell extern void *kmap_high(struct page *page); 48b8b572e1SStephen Rothwell extern void kunmap_high(struct page *page); 49b8b572e1SStephen Rothwell 50b8b572e1SStephen Rothwell static inline void *kmap(struct page *page) 51b8b572e1SStephen Rothwell { 52b8b572e1SStephen Rothwell might_sleep(); 53b8b572e1SStephen Rothwell if (!PageHighMem(page)) 54b8b572e1SStephen Rothwell return page_address(page); 55b8b572e1SStephen Rothwell return kmap_high(page); 56b8b572e1SStephen Rothwell } 57b8b572e1SStephen Rothwell 58b8b572e1SStephen Rothwell static inline void kunmap(struct page *page) 59b8b572e1SStephen Rothwell { 60b8b572e1SStephen Rothwell BUG_ON(in_interrupt()); 61b8b572e1SStephen Rothwell if (!PageHighMem(page)) 62b8b572e1SStephen Rothwell return; 63b8b572e1SStephen Rothwell kunmap_high(page); 64b8b572e1SStephen Rothwell } 65b8b572e1SStephen Rothwell 66b8b572e1SStephen Rothwell /* 67b8b572e1SStephen Rothwell * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap 68b8b572e1SStephen Rothwell * gives a more generic (and caching) interface. But kmap_atomic can 69b8b572e1SStephen Rothwell * be used in IRQ contexts, so in some (very limited) cases we need 70b8b572e1SStephen Rothwell * it. 71b8b572e1SStephen Rothwell */ 72b8b572e1SStephen Rothwell static inline void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot) 73b8b572e1SStephen Rothwell { 74b8b572e1SStephen Rothwell unsigned int idx; 75b8b572e1SStephen Rothwell unsigned long vaddr; 76b8b572e1SStephen Rothwell 77b8b572e1SStephen Rothwell /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */ 78b8b572e1SStephen Rothwell pagefault_disable(); 79b8b572e1SStephen Rothwell if (!PageHighMem(page)) 80b8b572e1SStephen Rothwell return page_address(page); 81b8b572e1SStephen Rothwell 82b8b572e1SStephen Rothwell idx = type + KM_TYPE_NR*smp_processor_id(); 83b8b572e1SStephen Rothwell vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); 84b8b572e1SStephen Rothwell #ifdef CONFIG_DEBUG_HIGHMEM 85b8b572e1SStephen Rothwell BUG_ON(!pte_none(*(kmap_pte-idx))); 86b8b572e1SStephen Rothwell #endif 87b8b572e1SStephen Rothwell set_pte_at(&init_mm, vaddr, kmap_pte-idx, mk_pte(page, prot)); 88b8b572e1SStephen Rothwell flush_tlb_page(NULL, vaddr); 89b8b572e1SStephen Rothwell 90b8b572e1SStephen Rothwell return (void*) vaddr; 91b8b572e1SStephen Rothwell } 92b8b572e1SStephen Rothwell 93b8b572e1SStephen Rothwell static inline void *kmap_atomic(struct page *page, enum km_type type) 94b8b572e1SStephen Rothwell { 95b8b572e1SStephen Rothwell return kmap_atomic_prot(page, type, kmap_prot); 96b8b572e1SStephen Rothwell } 97b8b572e1SStephen Rothwell 98b8b572e1SStephen Rothwell static inline void kunmap_atomic(void *kvaddr, enum km_type type) 99b8b572e1SStephen Rothwell { 100b8b572e1SStephen Rothwell #ifdef CONFIG_DEBUG_HIGHMEM 101b8b572e1SStephen Rothwell unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; 102b8b572e1SStephen Rothwell enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id(); 103b8b572e1SStephen Rothwell 104b8b572e1SStephen Rothwell if (vaddr < __fix_to_virt(FIX_KMAP_END)) { 105b8b572e1SStephen Rothwell pagefault_enable(); 106b8b572e1SStephen Rothwell return; 107b8b572e1SStephen Rothwell } 108b8b572e1SStephen Rothwell 109b8b572e1SStephen Rothwell BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx)); 110b8b572e1SStephen Rothwell 111b8b572e1SStephen Rothwell /* 112b8b572e1SStephen Rothwell * force other mappings to Oops if they'll try to access 113b8b572e1SStephen Rothwell * this pte without first remap it 114b8b572e1SStephen Rothwell */ 115b8b572e1SStephen Rothwell pte_clear(&init_mm, vaddr, kmap_pte-idx); 116b8b572e1SStephen Rothwell flush_tlb_page(NULL, vaddr); 117b8b572e1SStephen Rothwell #endif 118b8b572e1SStephen Rothwell pagefault_enable(); 119b8b572e1SStephen Rothwell } 120b8b572e1SStephen Rothwell 121b8b572e1SStephen Rothwell static inline struct page *kmap_atomic_to_page(void *ptr) 122b8b572e1SStephen Rothwell { 123b8b572e1SStephen Rothwell unsigned long idx, vaddr = (unsigned long) ptr; 124b8b572e1SStephen Rothwell pte_t *pte; 125b8b572e1SStephen Rothwell 126b8b572e1SStephen Rothwell if (vaddr < FIXADDR_START) 127b8b572e1SStephen Rothwell return virt_to_page(ptr); 128b8b572e1SStephen Rothwell 129b8b572e1SStephen Rothwell idx = virt_to_fix(vaddr); 130b8b572e1SStephen Rothwell pte = kmap_pte - (idx - FIX_KMAP_BEGIN); 131b8b572e1SStephen Rothwell return pte_page(*pte); 132b8b572e1SStephen Rothwell } 133b8b572e1SStephen Rothwell 134b8b572e1SStephen Rothwell #define flush_cache_kmaps() flush_cache_all() 135b8b572e1SStephen Rothwell 136b8b572e1SStephen Rothwell #endif /* __KERNEL__ */ 137b8b572e1SStephen Rothwell 138b8b572e1SStephen Rothwell #endif /* _ASM_HIGHMEM_H */ 139