include/linux/highmem-internal.h

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002 #ifndef _LINUX_HIGHMEM_INTERNAL_H
0003 #define _LINUX_HIGHMEM_INTERNAL_H
0004
0005 /*
0006  * Outside of CONFIG_HIGHMEM to support X86 32bit iomap_atomic() cruft.
0007  */
0008 #ifdef CONFIG_KMAP_LOCAL
0009 void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot);
0010 void *__kmap_local_page_prot(struct page *page, pgprot_t prot);
0011 void kunmap_local_indexed(const void *vaddr);
0012 void kmap_local_fork(struct task_struct *tsk);
0013 void __kmap_local_sched_out(void);
0014 void __kmap_local_sched_in(void);
0015 static inline void kmap_assert_nomap(void)
0016 {
0017     DEBUG_LOCKS_WARN_ON(current->kmap_ctrl.idx);
0018 }
0019 #else
0020 static inline void kmap_local_fork(struct task_struct *tsk) { }
0021 static inline void kmap_assert_nomap(void) { }
0022 #endif
0023
0024 #ifdef CONFIG_HIGHMEM
0025 #include <asm/highmem.h>
0026
0027 #ifndef ARCH_HAS_KMAP_FLUSH_TLB
0028 static inline void kmap_flush_tlb(unsigned long addr) { }
0029 #endif
0030
0031 #ifndef kmap_prot
0032 #define kmap_prot PAGE_KERNEL
0033 #endif
0034
0035 void *kmap_high(struct page *page);
0036 void kunmap_high(struct page *page);
0037 void __kmap_flush_unused(void);
0038 struct page *__kmap_to_page(void *addr);
0039
0040 static inline void *kmap(struct page *page)
0041 {
0042     void *addr;
0043
0044     might_sleep();
0045     if (!PageHighMem(page))
0046         addr = page_address(page);
0047     else
0048         addr = kmap_high(page);
0049     kmap_flush_tlb((unsigned long)addr);
0050     return addr;
0051 }
0052
0053 static inline void kunmap(struct page *page)
0054 {
0055     might_sleep();
0056     if (!PageHighMem(page))
0057         return;
0058     kunmap_high(page);
0059 }
0060
0061 static inline struct page *kmap_to_page(void *addr)
0062 {
0063     return __kmap_to_page(addr);
0064 }
0065
0066 static inline void kmap_flush_unused(void)
0067 {
0068     __kmap_flush_unused();
0069 }
0070
0071 static inline void *kmap_local_page(struct page *page)
0072 {
0073     return __kmap_local_page_prot(page, kmap_prot);
0074 }
0075
0076 static inline void *kmap_local_folio(struct folio *folio, size_t offset)
0077 {
0078     struct page *page = folio_page(folio, offset / PAGE_SIZE);
0079     return __kmap_local_page_prot(page, kmap_prot) + offset % PAGE_SIZE;
0080 }
0081
0082 static inline void *kmap_local_page_prot(struct page *page, pgprot_t prot)
0083 {
0084     return __kmap_local_page_prot(page, prot);
0085 }
0086
0087 static inline void *kmap_local_pfn(unsigned long pfn)
0088 {
0089     return __kmap_local_pfn_prot(pfn, kmap_prot);
0090 }
0091
0092 static inline void __kunmap_local(const void *vaddr)
0093 {
0094     kunmap_local_indexed(vaddr);
0095 }
0096
0097 static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
0098 {
0099     if (IS_ENABLED(CONFIG_PREEMPT_RT))
0100         migrate_disable();
0101     else
0102         preempt_disable();
0103
0104     pagefault_disable();
0105     return __kmap_local_page_prot(page, prot);
0106 }
0107
0108 static inline void *kmap_atomic(struct page *page)
0109 {
0110     return kmap_atomic_prot(page, kmap_prot);
0111 }
0112
0113 static inline void *kmap_atomic_pfn(unsigned long pfn)
0114 {
0115     if (IS_ENABLED(CONFIG_PREEMPT_RT))
0116         migrate_disable();
0117     else
0118         preempt_disable();
0119
0120     pagefault_disable();
0121     return __kmap_local_pfn_prot(pfn, kmap_prot);
0122 }
0123
0124 static inline void __kunmap_atomic(const void *addr)
0125 {
0126     kunmap_local_indexed(addr);
0127     pagefault_enable();
0128     if (IS_ENABLED(CONFIG_PREEMPT_RT))
0129         migrate_enable();
0130     else
0131         preempt_enable();
0132 }
0133
0134 unsigned int __nr_free_highpages(void);
0135 extern atomic_long_t _totalhigh_pages;
0136
0137 static inline unsigned int nr_free_highpages(void)
0138 {
0139     return __nr_free_highpages();
0140 }
0141
0142 static inline unsigned long totalhigh_pages(void)
0143 {
0144     return (unsigned long)atomic_long_read(&_totalhigh_pages);
0145 }
0146
0147 static inline void totalhigh_pages_add(long count)
0148 {
0149     atomic_long_add(count, &_totalhigh_pages);
0150 }
0151
0152 static inline bool is_kmap_addr(const void *x)
0153 {
0154     unsigned long addr = (unsigned long)x;
0155     return addr >= PKMAP_ADDR(0) && addr < PKMAP_ADDR(LAST_PKMAP);
0156 }
0157 #else /* CONFIG_HIGHMEM */
0158
0159 static inline struct page *kmap_to_page(void *addr)
0160 {
0161     return virt_to_page(addr);
0162 }
0163
0164 static inline void *kmap(struct page *page)
0165 {
0166     might_sleep();
0167     return page_address(page);
0168 }
0169
0170 static inline void kunmap_high(struct page *page) { }
0171 static inline void kmap_flush_unused(void) { }
0172
0173 static inline void kunmap(struct page *page)
0174 {
0175 #ifdef ARCH_HAS_FLUSH_ON_KUNMAP
0176     kunmap_flush_on_unmap(page_address(page));
0177 #endif
0178 }
0179
0180 static inline void *kmap_local_page(struct page *page)
0181 {
0182     return page_address(page);
0183 }
0184
0185 static inline void *kmap_local_folio(struct folio *folio, size_t offset)
0186 {
0187     return page_address(&folio->page) + offset;
0188 }
0189
0190 static inline void *kmap_local_page_prot(struct page *page, pgprot_t prot)
0191 {
0192     return kmap_local_page(page);
0193 }
0194
0195 static inline void *kmap_local_pfn(unsigned long pfn)
0196 {
0197     return kmap_local_page(pfn_to_page(pfn));
0198 }
0199
0200 static inline void __kunmap_local(const void *addr)
0201 {
0202 #ifdef ARCH_HAS_FLUSH_ON_KUNMAP
0203     kunmap_flush_on_unmap(addr);
0204 #endif
0205 }
0206
0207 static inline void *kmap_atomic(struct page *page)
0208 {
0209     if (IS_ENABLED(CONFIG_PREEMPT_RT))
0210         migrate_disable();
0211     else
0212         preempt_disable();
0213     pagefault_disable();
0214     return page_address(page);
0215 }
0216
0217 static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
0218 {
0219     return kmap_atomic(page);
0220 }
0221
0222 static inline void *kmap_atomic_pfn(unsigned long pfn)
0223 {
0224     return kmap_atomic(pfn_to_page(pfn));
0225 }
0226
0227 static inline void __kunmap_atomic(const void *addr)
0228 {
0229 #ifdef ARCH_HAS_FLUSH_ON_KUNMAP
0230     kunmap_flush_on_unmap(addr);
0231 #endif
0232     pagefault_enable();
0233     if (IS_ENABLED(CONFIG_PREEMPT_RT))
0234         migrate_enable();
0235     else
0236         preempt_enable();
0237 }
0238
0239 static inline unsigned int nr_free_highpages(void) { return 0; }
0240 static inline unsigned long totalhigh_pages(void) { return 0UL; }
0241
0242 static inline bool is_kmap_addr(const void *x)
0243 {
0244     return false;
0245 }
0246
0247 #endif /* CONFIG_HIGHMEM */
0248
0249 /**
0250  * kunmap_atomic - Unmap the virtual address mapped by kmap_atomic() - deprecated!
0251  * @__addr:       Virtual address to be unmapped
0252  *
0253  * Unmaps an address previously mapped by kmap_atomic() and re-enables
0254  * pagefaults. Depending on PREEMP_RT configuration, re-enables also
0255  * migration and preemption. Users should not count on these side effects.
0256  *
0257  * Mappings should be unmapped in the reverse order that they were mapped.
0258  * See kmap_local_page() for details on nesting.
0259  *
0260  * @__addr can be any address within the mapped page, so there is no need
0261  * to subtract any offset that has been added. In contrast to kunmap(),
0262  * this function takes the address returned from kmap_atomic(), not the
0263  * page passed to it. The compiler will warn you if you pass the page.
0264  */
0265 #define kunmap_atomic(__addr)                   \
0266 do {                                \
0267     BUILD_BUG_ON(__same_type((__addr), struct page *)); \
0268     __kunmap_atomic(__addr);                \
0269 } while (0)
0270
0271 /**
0272  * kunmap_local - Unmap a page mapped via kmap_local_page().
0273  * @__addr: An address within the page mapped
0274  *
0275  * @__addr can be any address within the mapped page.  Commonly it is the
0276  * address return from kmap_local_page(), but it can also include offsets.
0277  *
0278  * Unmapping should be done in the reverse order of the mapping.  See
0279  * kmap_local_page() for details.
0280  */
0281 #define kunmap_local(__addr)                    \
0282 do {                                \
0283     BUILD_BUG_ON(__same_type((__addr), struct page *)); \
0284     __kunmap_local(__addr);                 \
0285 } while (0)
0286
0287 #endif