highmem-internal.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef _LINUX_HIGHMEM_INTERNAL_H
  3#define _LINUX_HIGHMEM_INTERNAL_H
  4
  5/*
  6 * Outside of CONFIG_HIGHMEM to support X86 32bit iomap_atomic() cruft.
  7 */
  8#ifdef CONFIG_KMAP_LOCAL
  9void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot);
 10void *__kmap_local_page_prot(const struct page *page, pgprot_t prot);
 11void kunmap_local_indexed(const void *vaddr);
 12void kmap_local_fork(struct task_struct *tsk);
 13void __kmap_local_sched_out(void);
 14void __kmap_local_sched_in(void);
 15static inline void kmap_assert_nomap(void)
 16{
 17	DEBUG_LOCKS_WARN_ON(current->kmap_ctrl.idx);
 18}
 19#else
 20static inline void kmap_local_fork(struct task_struct *tsk) { }
 21static inline void kmap_assert_nomap(void) { }
 22#endif
 23
 24#ifdef CONFIG_HIGHMEM
 25#include <asm/highmem.h>
 26
 27#ifndef ARCH_HAS_KMAP_FLUSH_TLB
 28static inline void kmap_flush_tlb(unsigned long addr) { }
 29#endif
 30
 31#ifndef kmap_prot
 32#define kmap_prot PAGE_KERNEL
 33#endif
 34
 35void *kmap_high(struct page *page);
 36void kunmap_high(const struct page *page);
 37void __kmap_flush_unused(void);
 38struct page *__kmap_to_page(void *addr);
 39
 40static inline void *kmap(struct page *page)
 41{
 42	void *addr;
 43
 44	might_sleep();
 45	if (!PageHighMem(page))
 46		addr = page_address(page);
 47	else
 48		addr = kmap_high(page);
 49	kmap_flush_tlb((unsigned long)addr);
 50	return addr;
 51}
 52
 53static inline void kunmap(const struct page *page)
 54{
 55	might_sleep();
 56	if (!PageHighMem(page))
 57		return;
 58	kunmap_high(page);
 59}
 60
 61static inline struct page *kmap_to_page(void *addr)
 62{
 63	return __kmap_to_page(addr);
 64}
 65
 66static inline void kmap_flush_unused(void)
 67{
 68	__kmap_flush_unused();
 69}
 70
 71static inline void *kmap_local_page(const struct page *page)
 72{
 73	return __kmap_local_page_prot(page, kmap_prot);
 74}
 75
 76static inline void *kmap_local_page_try_from_panic(const struct page *page)
 77{
 78	if (!PageHighMem(page))
 79		return page_address(page);
 80	/* If the page is in HighMem, it's not safe to kmap it.*/
 81	return NULL;
 82}
 83
 84static inline void *kmap_local_folio(const struct folio *folio, size_t offset)
 85{
 86	const struct page *page = folio_page(folio, offset / PAGE_SIZE);
 87	return __kmap_local_page_prot(page, kmap_prot) + offset % PAGE_SIZE;
 88}
 89
 90static inline void *kmap_local_page_prot(const struct page *page, pgprot_t prot)
 91{
 92	return __kmap_local_page_prot(page, prot);
 93}
 94
 95static inline void *kmap_local_pfn(unsigned long pfn)
 96{
 97	return __kmap_local_pfn_prot(pfn, kmap_prot);
 98}
 99
100static inline void __kunmap_local(const void *vaddr)
101{
102	kunmap_local_indexed(vaddr);
103}
104
105static inline void *kmap_atomic_prot(const struct page *page, pgprot_t prot)
106{
107	if (IS_ENABLED(CONFIG_PREEMPT_RT))
108		migrate_disable();
109	else
110		preempt_disable();
111
112	pagefault_disable();
113	return __kmap_local_page_prot(page, prot);
114}
115
116static inline void *kmap_atomic(const struct page *page)
117{
118	return kmap_atomic_prot(page, kmap_prot);
119}
120
121static inline void *kmap_atomic_pfn(unsigned long pfn)
122{
123	if (IS_ENABLED(CONFIG_PREEMPT_RT))
124		migrate_disable();
125	else
126		preempt_disable();
127
128	pagefault_disable();
129	return __kmap_local_pfn_prot(pfn, kmap_prot);
130}
131
132static inline void __kunmap_atomic(const void *addr)
133{
134	kunmap_local_indexed(addr);
135	pagefault_enable();
136	if (IS_ENABLED(CONFIG_PREEMPT_RT))
137		migrate_enable();
138	else
139		preempt_enable();
140}
141
142unsigned long __nr_free_highpages(void);
143unsigned long __totalhigh_pages(void);
144
145static inline unsigned long nr_free_highpages(void)
146{
147	return __nr_free_highpages();
148}
149
150static inline unsigned long totalhigh_pages(void)
151{
152	return __totalhigh_pages();
153}
154
155static inline bool is_kmap_addr(const void *x)
156{
157	unsigned long addr = (unsigned long)x;
158
159	return (addr >= PKMAP_ADDR(0) && addr < PKMAP_ADDR(LAST_PKMAP)) ||
160		(addr >= __fix_to_virt(FIX_KMAP_END) &&
161		 addr < __fix_to_virt(FIX_KMAP_BEGIN));
162}
163#else /* CONFIG_HIGHMEM */
164
165static inline struct page *kmap_to_page(void *addr)
166{
167	return virt_to_page(addr);
168}
169
170static inline void *kmap(struct page *page)
171{
172	might_sleep();
173	return page_address(page);
174}
175
176static inline void kunmap_high(const struct page *page) { }
177static inline void kmap_flush_unused(void) { }
178
179static inline void kunmap(const struct page *page)
180{
181#ifdef ARCH_HAS_FLUSH_ON_KUNMAP
182	kunmap_flush_on_unmap(page_address(page));
183#endif
184}
185
186static inline void *kmap_local_page(const struct page *page)
187{
188	return page_address(page);
189}
190
191static inline void *kmap_local_page_try_from_panic(const struct page *page)
192{
193	return page_address(page);
194}
195
196static inline void *kmap_local_folio(const struct folio *folio, size_t offset)
197{
198	return folio_address(folio) + offset;
199}
200
201static inline void *kmap_local_page_prot(const struct page *page, pgprot_t prot)
202{
203	return kmap_local_page(page);
204}
205
206static inline void *kmap_local_pfn(unsigned long pfn)
207{
208	return kmap_local_page(pfn_to_page(pfn));
209}
210
211static inline void __kunmap_local(const void *addr)
212{
213#ifdef ARCH_HAS_FLUSH_ON_KUNMAP
214	kunmap_flush_on_unmap(PTR_ALIGN_DOWN(addr, PAGE_SIZE));
215#endif
216}
217
218static inline void *kmap_atomic(const struct page *page)
219{
220	if (IS_ENABLED(CONFIG_PREEMPT_RT))
221		migrate_disable();
222	else
223		preempt_disable();
224	pagefault_disable();
225	return page_address(page);
226}
227
228static inline void *kmap_atomic_prot(const struct page *page, pgprot_t prot)
229{
230	return kmap_atomic(page);
231}
232
233static inline void *kmap_atomic_pfn(unsigned long pfn)
234{
235	return kmap_atomic(pfn_to_page(pfn));
236}
237
238static inline void __kunmap_atomic(const void *addr)
239{
240#ifdef ARCH_HAS_FLUSH_ON_KUNMAP
241	kunmap_flush_on_unmap(PTR_ALIGN_DOWN(addr, PAGE_SIZE));
242#endif
243	pagefault_enable();
244	if (IS_ENABLED(CONFIG_PREEMPT_RT))
245		migrate_enable();
246	else
247		preempt_enable();
248}
249
250static inline unsigned long nr_free_highpages(void) { return 0; }
251static inline unsigned long totalhigh_pages(void) { return 0; }
252
253static inline bool is_kmap_addr(const void *x)
254{
255	return false;
256}
257
258#endif /* CONFIG_HIGHMEM */
259
260/**
261 * kunmap_atomic - Unmap the virtual address mapped by kmap_atomic() - deprecated!
262 * @__addr:       Virtual address to be unmapped
263 *
264 * Unmaps an address previously mapped by kmap_atomic() and re-enables
265 * pagefaults. Depending on PREEMP_RT configuration, re-enables also
266 * migration and preemption. Users should not count on these side effects.
267 *
268 * Mappings should be unmapped in the reverse order that they were mapped.
269 * See kmap_local_page() for details on nesting.
270 *
271 * @__addr can be any address within the mapped page, so there is no need
272 * to subtract any offset that has been added. In contrast to kunmap(),
273 * this function takes the address returned from kmap_atomic(), not the
274 * page passed to it. The compiler will warn you if you pass the page.
275 */
276#define kunmap_atomic(__addr)					\
277do {								\
278	BUILD_BUG_ON(__same_type((__addr), struct page *));	\
279	__kunmap_atomic(__addr);				\
280} while (0)
281
282/**
283 * kunmap_local - Unmap a page mapped via kmap_local_page().
284 * @__addr: An address within the page mapped
285 *
286 * @__addr can be any address within the mapped page.  Commonly it is the
287 * address return from kmap_local_page(), but it can also include offsets.
288 *
289 * Unmapping should be done in the reverse order of the mapping.  See
290 * kmap_local_page() for details.
291 */
292#define kunmap_local(__addr)					\
293do {								\
294	BUILD_BUG_ON(__same_type((__addr), struct page *));	\
295	__kunmap_local(__addr);					\
296} while (0)
297
298#endif