Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * highmem.c: virtual kernel memory mappings for high memory |
| 3 | * |
| 4 | * Provides kernel-static versions of atomic kmap functions originally |
| 5 | * found as inlines in include/asm-sparc/highmem.h. These became |
| 6 | * needed as kmap_atomic() and kunmap_atomic() started getting |
| 7 | * called from within modules. |
| 8 | * -- Tomas Szepe <szepe@pinerecords.com>, September 2002 |
| 9 | * |
| 10 | * But kmap_atomic() and kunmap_atomic() cannot be inlined in |
| 11 | * modules because they are loaded with btfixup-ped functions. |
| 12 | */ |
| 13 | |
| 14 | /* |
| 15 | * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap |
| 16 | * gives a more generic (and caching) interface. But kmap_atomic can |
| 17 | * be used in IRQ contexts, so in some (very limited) cases we need it. |
| 18 | * |
| 19 | * XXX This is an old text. Actually, it's good to use atomic kmaps, |
| 20 | * provided you remember that they are atomic and not try to sleep |
| 21 | * with a kmap taken, much like a spinlock. Non-atomic kmaps are |
| 22 | * shared by CPUs, and so precious, and establishing them requires IPI. |
| 23 | * Atomic kmaps are lightweight and we may have NCPUS more of them. |
| 24 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | #include <linux/highmem.h> |
Paul Gortmaker | 7b64db6 | 2011-07-18 15:57:46 -0400 | [diff] [blame] | 26 | #include <linux/export.h> |
Sam Ravnborg | 1b6d06d8 | 2012-07-26 11:02:19 +0000 | [diff] [blame] | 27 | #include <linux/mm.h> |
| 28 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | #include <asm/cacheflush.h> |
| 30 | #include <asm/tlbflush.h> |
Sam Ravnborg | 1b6d06d8 | 2012-07-26 11:02:19 +0000 | [diff] [blame] | 31 | #include <asm/pgalloc.h> |
| 32 | #include <asm/vaddrs.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 33 | |
Sam Ravnborg | 9a4d5b9 | 2012-07-26 11:02:27 +0000 | [diff] [blame] | 34 | pgprot_t kmap_prot; |
| 35 | |
| 36 | static pte_t *kmap_pte; |
| 37 | |
| 38 | void __init kmap_init(void) |
| 39 | { |
| 40 | unsigned long address; |
| 41 | pmd_t *dir; |
| 42 | |
| 43 | address = __fix_to_virt(FIX_KMAP_BEGIN); |
| 44 | dir = pmd_offset(pgd_offset_k(address), address); |
| 45 | |
| 46 | /* cache the first kmap pte */ |
| 47 | kmap_pte = pte_offset_kernel(dir, address); |
| 48 | kmap_prot = __pgprot(SRMMU_ET_PTE | SRMMU_PRIV | SRMMU_CACHE); |
| 49 | } |
| 50 | |
Cong Wang | a24401b | 2011-11-26 10:53:39 +0800 | [diff] [blame] | 51 | void *kmap_atomic(struct page *page) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 52 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 53 | unsigned long vaddr; |
Peter Zijlstra | 3e4d3af | 2010-10-26 14:21:51 -0700 | [diff] [blame] | 54 | long idx, type; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 55 | |
David Hildenbrand | 2cb7c9c | 2015-05-11 17:52:09 +0200 | [diff] [blame] | 56 | preempt_disable(); |
Peter Zijlstra | a866374 | 2006-12-06 20:32:20 -0800 | [diff] [blame] | 57 | pagefault_disable(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 58 | if (!PageHighMem(page)) |
| 59 | return page_address(page); |
| 60 | |
Peter Zijlstra | 3e4d3af | 2010-10-26 14:21:51 -0700 | [diff] [blame] | 61 | type = kmap_atomic_idx_push(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 62 | idx = type + KM_TYPE_NR*smp_processor_id(); |
| 63 | vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); |
| 64 | |
| 65 | /* XXX Fix - Anton */ |
| 66 | #if 0 |
| 67 | __flush_cache_one(vaddr); |
| 68 | #else |
| 69 | flush_cache_all(); |
| 70 | #endif |
| 71 | |
| 72 | #ifdef CONFIG_DEBUG_HIGHMEM |
| 73 | BUG_ON(!pte_none(*(kmap_pte-idx))); |
| 74 | #endif |
| 75 | set_pte(kmap_pte-idx, mk_pte(page, kmap_prot)); |
| 76 | /* XXX Fix - Anton */ |
| 77 | #if 0 |
| 78 | __flush_tlb_one(vaddr); |
| 79 | #else |
| 80 | flush_tlb_all(); |
| 81 | #endif |
| 82 | |
| 83 | return (void*) vaddr; |
| 84 | } |
Cong Wang | a24401b | 2011-11-26 10:53:39 +0800 | [diff] [blame] | 85 | EXPORT_SYMBOL(kmap_atomic); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 86 | |
Peter Zijlstra | 3e4d3af | 2010-10-26 14:21:51 -0700 | [diff] [blame] | 87 | void __kunmap_atomic(void *kvaddr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 88 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 89 | unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; |
Peter Zijlstra | 3e4d3af | 2010-10-26 14:21:51 -0700 | [diff] [blame] | 90 | int type; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 91 | |
| 92 | if (vaddr < FIXADDR_START) { // FIXME |
Peter Zijlstra | a866374 | 2006-12-06 20:32:20 -0800 | [diff] [blame] | 93 | pagefault_enable(); |
David Hildenbrand | 2cb7c9c | 2015-05-11 17:52:09 +0200 | [diff] [blame] | 94 | preempt_enable(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 95 | return; |
| 96 | } |
| 97 | |
Peter Zijlstra | 2027394 | 2010-10-27 15:32:58 -0700 | [diff] [blame] | 98 | type = kmap_atomic_idx(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 99 | |
Peter Zijlstra | 3e4d3af | 2010-10-26 14:21:51 -0700 | [diff] [blame] | 100 | #ifdef CONFIG_DEBUG_HIGHMEM |
| 101 | { |
| 102 | unsigned long idx; |
| 103 | |
| 104 | idx = type + KM_TYPE_NR * smp_processor_id(); |
| 105 | BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN+idx)); |
| 106 | |
| 107 | /* XXX Fix - Anton */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 108 | #if 0 |
Peter Zijlstra | 3e4d3af | 2010-10-26 14:21:51 -0700 | [diff] [blame] | 109 | __flush_cache_one(vaddr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 110 | #else |
Peter Zijlstra | 3e4d3af | 2010-10-26 14:21:51 -0700 | [diff] [blame] | 111 | flush_cache_all(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 112 | #endif |
| 113 | |
Peter Zijlstra | 3e4d3af | 2010-10-26 14:21:51 -0700 | [diff] [blame] | 114 | /* |
| 115 | * force other mappings to Oops if they'll try to access |
| 116 | * this pte without first remap it |
| 117 | */ |
| 118 | pte_clear(&init_mm, vaddr, kmap_pte-idx); |
| 119 | /* XXX Fix - Anton */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 120 | #if 0 |
Peter Zijlstra | 3e4d3af | 2010-10-26 14:21:51 -0700 | [diff] [blame] | 121 | __flush_tlb_one(vaddr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 122 | #else |
Peter Zijlstra | 3e4d3af | 2010-10-26 14:21:51 -0700 | [diff] [blame] | 123 | flush_tlb_all(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 124 | #endif |
Peter Zijlstra | 3e4d3af | 2010-10-26 14:21:51 -0700 | [diff] [blame] | 125 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | #endif |
Peter Zijlstra | 2027394 | 2010-10-27 15:32:58 -0700 | [diff] [blame] | 127 | |
| 128 | kmap_atomic_idx_pop(); |
Peter Zijlstra | a866374 | 2006-12-06 20:32:20 -0800 | [diff] [blame] | 129 | pagefault_enable(); |
David Hildenbrand | 2cb7c9c | 2015-05-11 17:52:09 +0200 | [diff] [blame] | 130 | preempt_enable(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 131 | } |
Peter Zijlstra | 3e4d3af | 2010-10-26 14:21:51 -0700 | [diff] [blame] | 132 | EXPORT_SYMBOL(__kunmap_atomic); |