1 // SPDX-License-Identifier: GPL-2.0 2 // Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd. 3 4 #include <linux/module.h> 5 #include <linux/highmem.h> 6 #include <linux/smp.h> 7 #include <linux/memblock.h> 8 #include <asm/fixmap.h> 9 #include <asm/tlbflush.h> 10 #include <asm/cacheflush.h> 11 12 static pte_t *kmap_pte; 13 14 unsigned long highstart_pfn, highend_pfn; 15 16 void kmap_flush_tlb(unsigned long addr) 17 { 18 flush_tlb_one(addr); 19 } 20 EXPORT_SYMBOL(kmap_flush_tlb); 21 22 EXPORT_SYMBOL(kmap); 23 24 void kunmap(struct page *page) 25 { 26 might_sleep(); 27 if (!PageHighMem(page)) 28 return; 29 kunmap_high(page); 30 } 31 EXPORT_SYMBOL(kunmap); 32 33 void *kmap_atomic(struct page *page) 34 { 35 unsigned long vaddr; 36 int idx, type; 37 38 preempt_disable(); 39 pagefault_disable(); 40 if (!PageHighMem(page)) 41 return page_address(page); 42 43 type = kmap_atomic_idx_push(); 44 idx = type + KM_TYPE_NR*smp_processor_id(); 45 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); 46 #ifdef CONFIG_DEBUG_HIGHMEM 47 BUG_ON(!pte_none(*(kmap_pte - idx))); 48 #endif 49 set_pte(kmap_pte-idx, mk_pte(page, PAGE_KERNEL)); 50 flush_tlb_one((unsigned long)vaddr); 51 52 return (void *)vaddr; 53 } 54 EXPORT_SYMBOL(kmap_atomic); 55 56 void __kunmap_atomic(void *kvaddr) 57 { 58 unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; 59 int idx; 60 61 if (vaddr < FIXADDR_START) 62 goto out; 63 64 #ifdef CONFIG_DEBUG_HIGHMEM 65 idx = KM_TYPE_NR*smp_processor_id() + kmap_atomic_idx(); 66 67 BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx)); 68 69 pte_clear(&init_mm, vaddr, kmap_pte - idx); 70 flush_tlb_one(vaddr); 71 #else 72 (void) idx; /* to kill a warning */ 73 #endif 74 kmap_atomic_idx_pop(); 75 out: 76 pagefault_enable(); 77 preempt_enable(); 78 } 79 EXPORT_SYMBOL(__kunmap_atomic); 80 81 /* 82 * This is the same as kmap_atomic() but can map memory that doesn't 83 * have a struct page associated with it. 84 */ 85 void *kmap_atomic_pfn(unsigned long pfn) 86 { 87 unsigned long vaddr; 88 int idx, type; 89 90 pagefault_disable(); 91 92 type = kmap_atomic_idx_push(); 93 idx = type + KM_TYPE_NR*smp_processor_id(); 94 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); 95 set_pte(kmap_pte-idx, pfn_pte(pfn, PAGE_KERNEL)); 96 flush_tlb_one(vaddr); 97 98 return (void *) vaddr; 99 } 100 101 struct page *kmap_atomic_to_page(void *ptr) 102 { 103 unsigned long idx, vaddr = (unsigned long)ptr; 104 pte_t *pte; 105 106 if (vaddr < FIXADDR_START) 107 return virt_to_page(ptr); 108 109 idx = virt_to_fix(vaddr); 110 pte = kmap_pte - (idx - FIX_KMAP_BEGIN); 111 return pte_page(*pte); 112 } 113 114 static void __init kmap_pages_init(void) 115 { 116 unsigned long vaddr; 117 pgd_t *pgd; 118 pmd_t *pmd; 119 pud_t *pud; 120 pte_t *pte; 121 122 vaddr = PKMAP_BASE; 123 fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, swapper_pg_dir); 124 125 pgd = swapper_pg_dir + __pgd_offset(vaddr); 126 pud = (pud_t *)pgd; 127 pmd = pmd_offset(pud, vaddr); 128 pte = pte_offset_kernel(pmd, vaddr); 129 pkmap_page_table = pte; 130 } 131 132 void __init kmap_init(void) 133 { 134 unsigned long vaddr; 135 136 kmap_pages_init(); 137 138 vaddr = __fix_to_virt(FIX_KMAP_BEGIN); 139 140 kmap_pte = pte_offset_kernel((pmd_t *)pgd_offset_k(vaddr), vaddr); 141 } 142