1 // SPDX-License-Identifier: GPL-2.0-only
3 * arch/arm/mm/highmem.c -- ARM highmem support
5 * Author: Nicolas Pitre
6 * Created: september 8, 2008
7 * Copyright: Marvell Semiconductors Inc.
10 #include <linux/module.h>
11 #include <linux/highmem.h>
12 #include <linux/interrupt.h>
13 #include <asm/fixmap.h>
14 #include <asm/cacheflush.h>
15 #include <asm/tlbflush.h>
18 static inline void set_fixmap_pte(int idx, pte_t pte)
20 unsigned long vaddr = __fix_to_virt(idx);
21 pte_t *ptep = pte_offset_kernel(pmd_off_k(vaddr), vaddr);
23 set_pte_ext(ptep, pte, 0);
24 local_flush_tlb_kernel_page(vaddr);
27 static inline pte_t get_fixmap_pte(unsigned long vaddr)
29 pte_t *ptep = pte_offset_kernel(pmd_off_k(vaddr), vaddr);
34 void *kmap(struct page *page)
37 if (!PageHighMem(page))
38 return page_address(page);
39 return kmap_high(page);
43 void kunmap(struct page *page)
45 BUG_ON(in_interrupt());
46 if (!PageHighMem(page))
50 EXPORT_SYMBOL(kunmap);
52 void *kmap_atomic(struct page *page)
61 if (!PageHighMem(page))
62 return page_address(page);
64 #ifdef CONFIG_DEBUG_HIGHMEM
66 * There is no cache coherency issue when non VIVT, so force the
67 * dedicated kmap usage for better debugging purposes in that case.
73 kmap = kmap_high_get(page);
77 type = kmap_atomic_idx_push();
79 idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
80 vaddr = __fix_to_virt(idx);
81 #ifdef CONFIG_DEBUG_HIGHMEM
83 * With debugging enabled, kunmap_atomic forces that entry to 0.
84 * Make sure it was indeed properly unmapped.
86 BUG_ON(!pte_none(get_fixmap_pte(vaddr)));
89 * When debugging is off, kunmap_atomic leaves the previous mapping
90 * in place, so the contained TLB flush ensures the TLB is updated
91 * with the new mapping.
93 set_fixmap_pte(idx, mk_pte(page, kmap_prot));
97 EXPORT_SYMBOL(kmap_atomic);
99 void __kunmap_atomic(void *kvaddr)
101 unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
104 if (kvaddr >= (void *)FIXADDR_START) {
105 type = kmap_atomic_idx();
106 idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
109 __cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
110 #ifdef CONFIG_DEBUG_HIGHMEM
111 BUG_ON(vaddr != __fix_to_virt(idx));
112 set_fixmap_pte(idx, __pte(0));
114 (void) idx; /* to kill a warning */
116 kmap_atomic_idx_pop();
117 } else if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) {
118 /* this address was obtained through kmap_high_get() */
119 kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)]));
124 EXPORT_SYMBOL(__kunmap_atomic);
126 void *kmap_atomic_pfn(unsigned long pfn)
130 struct page *page = pfn_to_page(pfn);
134 if (!PageHighMem(page))
135 return page_address(page);
137 type = kmap_atomic_idx_push();
138 idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
139 vaddr = __fix_to_virt(idx);
140 #ifdef CONFIG_DEBUG_HIGHMEM
141 BUG_ON(!pte_none(get_fixmap_pte(vaddr)));
143 set_fixmap_pte(idx, pfn_pte(pfn, kmap_prot));
145 return (void *)vaddr;