Greg Kroah-Hartman | b244131 | 2017-11-01 15:07:57 +0100 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2 | /* |
| 3 | * High memory handling common code and variables. |
| 4 | * |
| 5 | * (C) 1999 Andrea Arcangeli, SuSE GmbH, andrea@suse.de |
| 6 | * Gerhard Wichert, Siemens AG, Gerhard.Wichert@pdb.siemens.de |
| 7 | * |
| 8 | * |
| 9 | * Redesigned the x86 32-bit VM architecture to deal with |
| 10 | * 64-bit physical space. With current x86 CPUs this |
| 11 | * means up to 64 Gigabytes physical RAM. |
| 12 | * |
| 13 | * Rewrote high memory support to move the page cache into |
| 14 | * high memory. Implemented permanent (schedulable) kmaps |
| 15 | * based on Linus' idea. |
| 16 | * |
| 17 | * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com> |
| 18 | */ |
| 19 | |
| 20 | #include <linux/mm.h> |
Paul Gortmaker | b95f1b31 | 2011-10-16 02:01:52 -0400 | [diff] [blame] | 21 | #include <linux/export.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 22 | #include <linux/swap.h> |
| 23 | #include <linux/bio.h> |
| 24 | #include <linux/pagemap.h> |
| 25 | #include <linux/mempool.h> |
| 26 | #include <linux/blkdev.h> |
| 27 | #include <linux/init.h> |
| 28 | #include <linux/hash.h> |
| 29 | #include <linux/highmem.h> |
Jason Wessel | eac79005 | 2010-08-05 09:22:24 -0500 | [diff] [blame] | 30 | #include <linux/kgdb.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 31 | #include <asm/tlbflush.h> |
Ingo Molnar | 186525b | 2019-11-29 08:17:25 +0100 | [diff] [blame] | 32 | #include <linux/vmalloc.h> |
Peter Zijlstra | a8e23a2 | 2010-10-27 15:32:57 -0700 | [diff] [blame] | 33 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | /* |
| 35 | * Virtual_count is not a pure "count". |
| 36 | * 0 means that it is not mapped, and has not been mapped |
| 37 | * since a TLB flush - it is usable. |
| 38 | * 1 means that there are no users, but it has been mapped |
| 39 | * since the last TLB flush - so we can't use it. |
| 40 | * n means that there are (n-1) current users of it. |
| 41 | */ |
| 42 | #ifdef CONFIG_HIGHMEM |
Al Viro | 260b236 | 2005-10-21 03:22:44 -0400 | [diff] [blame] | 43 | |
Max Filippov | 15de36a | 2014-08-06 16:08:23 -0700 | [diff] [blame] | 44 | /* |
| 45 | * Architecture with aliasing data cache may define the following family of |
| 46 | * helper functions in its asm/highmem.h to control cache color of virtual |
| 47 | * addresses where physical memory pages are mapped by kmap. |
| 48 | */ |
| 49 | #ifndef get_pkmap_color |
| 50 | |
| 51 | /* |
| 52 | * Determine color of virtual address where the page should be mapped. |
| 53 | */ |
| 54 | static inline unsigned int get_pkmap_color(struct page *page) |
| 55 | { |
| 56 | return 0; |
| 57 | } |
| 58 | #define get_pkmap_color get_pkmap_color |
| 59 | |
| 60 | /* |
| 61 | * Get next index for mapping inside PKMAP region for page with given color. |
| 62 | */ |
| 63 | static inline unsigned int get_next_pkmap_nr(unsigned int color) |
| 64 | { |
| 65 | static unsigned int last_pkmap_nr; |
| 66 | |
| 67 | last_pkmap_nr = (last_pkmap_nr + 1) & LAST_PKMAP_MASK; |
| 68 | return last_pkmap_nr; |
| 69 | } |
| 70 | |
| 71 | /* |
| 72 | * Determine if page index inside PKMAP region (pkmap_nr) of given color |
| 73 | * has wrapped around PKMAP region end. When this happens an attempt to |
| 74 | * flush all unused PKMAP slots is made. |
| 75 | */ |
| 76 | static inline int no_more_pkmaps(unsigned int pkmap_nr, unsigned int color) |
| 77 | { |
| 78 | return pkmap_nr == 0; |
| 79 | } |
| 80 | |
| 81 | /* |
| 82 | * Get the number of PKMAP entries of the given color. If no free slot is |
| 83 | * found after checking that many entries, kmap will sleep waiting for |
| 84 | * someone to call kunmap and free PKMAP slot. |
| 85 | */ |
| 86 | static inline int get_pkmap_entries_count(unsigned int color) |
| 87 | { |
| 88 | return LAST_PKMAP; |
| 89 | } |
| 90 | |
| 91 | /* |
| 92 | * Get head of a wait queue for PKMAP entries of the given color. |
| 93 | * Wait queues for different mapping colors should be independent to avoid |
| 94 | * unnecessary wakeups caused by freeing of slots of other colors. |
| 95 | */ |
| 96 | static inline wait_queue_head_t *get_pkmap_wait_queue_head(unsigned int color) |
| 97 | { |
| 98 | static DECLARE_WAIT_QUEUE_HEAD(pkmap_map_wait); |
| 99 | |
| 100 | return &pkmap_map_wait; |
| 101 | } |
| 102 | #endif |
| 103 | |
Arun KS | ca79b0c | 2018-12-28 00:34:29 -0800 | [diff] [blame] | 104 | atomic_long_t _totalhigh_pages __read_mostly; |
| 105 | EXPORT_SYMBOL(_totalhigh_pages); |
Peter Zijlstra | 3e4d3af | 2010-10-26 14:21:51 -0700 | [diff] [blame] | 106 | |
Thomas Gleixner | 13f876b | 2020-11-03 10:27:34 +0100 | [diff] [blame] | 107 | unsigned int __nr_free_highpages (void) |
Christoph Lameter | c1f60a5 | 2006-09-25 23:31:11 -0700 | [diff] [blame] | 108 | { |
Joonsoo Kim | 33499bf | 2016-05-19 17:12:26 -0700 | [diff] [blame] | 109 | struct zone *zone; |
Christoph Lameter | c1f60a5 | 2006-09-25 23:31:11 -0700 | [diff] [blame] | 110 | unsigned int pages = 0; |
| 111 | |
Joonsoo Kim | 33499bf | 2016-05-19 17:12:26 -0700 | [diff] [blame] | 112 | for_each_populated_zone(zone) { |
| 113 | if (is_highmem(zone)) |
| 114 | pages += zone_page_state(zone, NR_FREE_PAGES); |
Mel Gorman | 2a1e274 | 2007-07-17 04:03:12 -0700 | [diff] [blame] | 115 | } |
Christoph Lameter | c1f60a5 | 2006-09-25 23:31:11 -0700 | [diff] [blame] | 116 | |
| 117 | return pages; |
| 118 | } |
| 119 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 120 | static int pkmap_count[LAST_PKMAP]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 121 | static __cacheline_aligned_in_smp DEFINE_SPINLOCK(kmap_lock); |
| 122 | |
| 123 | pte_t * pkmap_page_table; |
| 124 | |
Nicolas Pitre | 3297e76 | 2009-03-04 22:49:41 -0500 | [diff] [blame] | 125 | /* |
| 126 | * Most architectures have no use for kmap_high_get(), so let's abstract |
| 127 | * the disabling of IRQ out of the locking in that case to save on a |
| 128 | * potential useless overhead. |
| 129 | */ |
| 130 | #ifdef ARCH_NEEDS_KMAP_HIGH_GET |
| 131 | #define lock_kmap() spin_lock_irq(&kmap_lock) |
| 132 | #define unlock_kmap() spin_unlock_irq(&kmap_lock) |
| 133 | #define lock_kmap_any(flags) spin_lock_irqsave(&kmap_lock, flags) |
| 134 | #define unlock_kmap_any(flags) spin_unlock_irqrestore(&kmap_lock, flags) |
| 135 | #else |
| 136 | #define lock_kmap() spin_lock(&kmap_lock) |
| 137 | #define unlock_kmap() spin_unlock(&kmap_lock) |
| 138 | #define lock_kmap_any(flags) \ |
| 139 | do { spin_lock(&kmap_lock); (void)(flags); } while (0) |
| 140 | #define unlock_kmap_any(flags) \ |
| 141 | do { spin_unlock(&kmap_lock); (void)(flags); } while (0) |
| 142 | #endif |
| 143 | |
Thomas Gleixner | 13f876b | 2020-11-03 10:27:34 +0100 | [diff] [blame] | 144 | struct page *__kmap_to_page(void *vaddr) |
Mel Gorman | 5a17811 | 2012-07-31 16:45:02 -0700 | [diff] [blame] | 145 | { |
| 146 | unsigned long addr = (unsigned long)vaddr; |
| 147 | |
Will Deacon | 498c228 | 2012-11-16 14:15:00 -0800 | [diff] [blame] | 148 | if (addr >= PKMAP_ADDR(0) && addr < PKMAP_ADDR(LAST_PKMAP)) { |
Joonsoo Kim | 4de22c0 | 2012-12-11 16:01:17 -0800 | [diff] [blame] | 149 | int i = PKMAP_NR(addr); |
Mel Gorman | 5a17811 | 2012-07-31 16:45:02 -0700 | [diff] [blame] | 150 | return pte_page(pkmap_page_table[i]); |
| 151 | } |
| 152 | |
| 153 | return virt_to_page(addr); |
| 154 | } |
Thomas Gleixner | 13f876b | 2020-11-03 10:27:34 +0100 | [diff] [blame] | 155 | EXPORT_SYMBOL(__kmap_to_page); |
Mel Gorman | 5a17811 | 2012-07-31 16:45:02 -0700 | [diff] [blame] | 156 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 157 | static void flush_all_zero_pkmaps(void) |
| 158 | { |
| 159 | int i; |
Nick Piggin | 5843d9a | 2008-08-01 03:15:21 +0200 | [diff] [blame] | 160 | int need_flush = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 161 | |
| 162 | flush_cache_kmaps(); |
| 163 | |
| 164 | for (i = 0; i < LAST_PKMAP; i++) { |
| 165 | struct page *page; |
| 166 | |
| 167 | /* |
| 168 | * zero means we don't have anything to do, |
| 169 | * >1 means that it is still in use. Only |
| 170 | * a count of 1 means that it is free but |
| 171 | * needs to be unmapped |
| 172 | */ |
| 173 | if (pkmap_count[i] != 1) |
| 174 | continue; |
| 175 | pkmap_count[i] = 0; |
| 176 | |
| 177 | /* sanity check */ |
Eric Sesterhenn | 75babca | 2006-04-02 13:47:35 +0200 | [diff] [blame] | 178 | BUG_ON(pte_none(pkmap_page_table[i])); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 179 | |
| 180 | /* |
| 181 | * Don't need an atomic fetch-and-clear op here; |
| 182 | * no-one has the page mapped, and cannot get at |
| 183 | * its virtual address (and hence PTE) without first |
| 184 | * getting the kmap_lock (which is held here). |
| 185 | * So no dangers, even with speculative execution. |
| 186 | */ |
| 187 | page = pte_page(pkmap_page_table[i]); |
Joonsoo Kim | eb2db43 | 2012-12-11 16:01:24 -0800 | [diff] [blame] | 188 | pte_clear(&init_mm, PKMAP_ADDR(i), &pkmap_page_table[i]); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 189 | |
| 190 | set_page_address(page, NULL); |
Nick Piggin | 5843d9a | 2008-08-01 03:15:21 +0200 | [diff] [blame] | 191 | need_flush = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 192 | } |
Nick Piggin | 5843d9a | 2008-08-01 03:15:21 +0200 | [diff] [blame] | 193 | if (need_flush) |
| 194 | flush_tlb_kernel_range(PKMAP_ADDR(0), PKMAP_ADDR(LAST_PKMAP)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 195 | } |
| 196 | |
Thomas Gleixner | 13f876b | 2020-11-03 10:27:34 +0100 | [diff] [blame] | 197 | void __kmap_flush_unused(void) |
Jeremy Fitzhardinge | ce6234b | 2007-05-02 19:27:15 +0200 | [diff] [blame] | 198 | { |
Nicolas Pitre | 3297e76 | 2009-03-04 22:49:41 -0500 | [diff] [blame] | 199 | lock_kmap(); |
Jeremy Fitzhardinge | ce6234b | 2007-05-02 19:27:15 +0200 | [diff] [blame] | 200 | flush_all_zero_pkmaps(); |
Nicolas Pitre | 3297e76 | 2009-03-04 22:49:41 -0500 | [diff] [blame] | 201 | unlock_kmap(); |
Jeremy Fitzhardinge | ce6234b | 2007-05-02 19:27:15 +0200 | [diff] [blame] | 202 | } |
| 203 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 204 | static inline unsigned long map_new_virtual(struct page *page) |
| 205 | { |
| 206 | unsigned long vaddr; |
| 207 | int count; |
Max Filippov | 15de36a | 2014-08-06 16:08:23 -0700 | [diff] [blame] | 208 | unsigned int last_pkmap_nr; |
| 209 | unsigned int color = get_pkmap_color(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 210 | |
| 211 | start: |
Max Filippov | 15de36a | 2014-08-06 16:08:23 -0700 | [diff] [blame] | 212 | count = get_pkmap_entries_count(color); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 213 | /* Find an empty entry */ |
| 214 | for (;;) { |
Max Filippov | 15de36a | 2014-08-06 16:08:23 -0700 | [diff] [blame] | 215 | last_pkmap_nr = get_next_pkmap_nr(color); |
| 216 | if (no_more_pkmaps(last_pkmap_nr, color)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 217 | flush_all_zero_pkmaps(); |
Max Filippov | 15de36a | 2014-08-06 16:08:23 -0700 | [diff] [blame] | 218 | count = get_pkmap_entries_count(color); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 219 | } |
| 220 | if (!pkmap_count[last_pkmap_nr]) |
| 221 | break; /* Found a usable entry */ |
| 222 | if (--count) |
| 223 | continue; |
| 224 | |
| 225 | /* |
| 226 | * Sleep for somebody else to unmap their entries |
| 227 | */ |
| 228 | { |
| 229 | DECLARE_WAITQUEUE(wait, current); |
Max Filippov | 15de36a | 2014-08-06 16:08:23 -0700 | [diff] [blame] | 230 | wait_queue_head_t *pkmap_map_wait = |
| 231 | get_pkmap_wait_queue_head(color); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 232 | |
| 233 | __set_current_state(TASK_UNINTERRUPTIBLE); |
Max Filippov | 15de36a | 2014-08-06 16:08:23 -0700 | [diff] [blame] | 234 | add_wait_queue(pkmap_map_wait, &wait); |
Nicolas Pitre | 3297e76 | 2009-03-04 22:49:41 -0500 | [diff] [blame] | 235 | unlock_kmap(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 236 | schedule(); |
Max Filippov | 15de36a | 2014-08-06 16:08:23 -0700 | [diff] [blame] | 237 | remove_wait_queue(pkmap_map_wait, &wait); |
Nicolas Pitre | 3297e76 | 2009-03-04 22:49:41 -0500 | [diff] [blame] | 238 | lock_kmap(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 239 | |
| 240 | /* Somebody else might have mapped it while we slept */ |
| 241 | if (page_address(page)) |
| 242 | return (unsigned long)page_address(page); |
| 243 | |
| 244 | /* Re-start */ |
| 245 | goto start; |
| 246 | } |
| 247 | } |
| 248 | vaddr = PKMAP_ADDR(last_pkmap_nr); |
| 249 | set_pte_at(&init_mm, vaddr, |
| 250 | &(pkmap_page_table[last_pkmap_nr]), mk_pte(page, kmap_prot)); |
| 251 | |
| 252 | pkmap_count[last_pkmap_nr] = 1; |
| 253 | set_page_address(page, (void *)vaddr); |
| 254 | |
| 255 | return vaddr; |
| 256 | } |
| 257 | |
Randy Dunlap | 77f6078 | 2008-03-19 17:00:42 -0700 | [diff] [blame] | 258 | /** |
| 259 | * kmap_high - map a highmem page into memory |
| 260 | * @page: &struct page to map |
| 261 | * |
| 262 | * Returns the page's virtual memory address. |
| 263 | * |
| 264 | * We cannot call this from interrupts, as it may block. |
| 265 | */ |
Harvey Harrison | 920c7a5 | 2008-02-04 22:29:26 -0800 | [diff] [blame] | 266 | void *kmap_high(struct page *page) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 267 | { |
| 268 | unsigned long vaddr; |
| 269 | |
| 270 | /* |
| 271 | * For highmem pages, we can't trust "virtual" until |
| 272 | * after we have the lock. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 273 | */ |
Nicolas Pitre | 3297e76 | 2009-03-04 22:49:41 -0500 | [diff] [blame] | 274 | lock_kmap(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 275 | vaddr = (unsigned long)page_address(page); |
| 276 | if (!vaddr) |
| 277 | vaddr = map_new_virtual(page); |
| 278 | pkmap_count[PKMAP_NR(vaddr)]++; |
Eric Sesterhenn | 75babca | 2006-04-02 13:47:35 +0200 | [diff] [blame] | 279 | BUG_ON(pkmap_count[PKMAP_NR(vaddr)] < 2); |
Nicolas Pitre | 3297e76 | 2009-03-04 22:49:41 -0500 | [diff] [blame] | 280 | unlock_kmap(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 281 | return (void*) vaddr; |
| 282 | } |
| 283 | |
| 284 | EXPORT_SYMBOL(kmap_high); |
| 285 | |
Nicolas Pitre | 3297e76 | 2009-03-04 22:49:41 -0500 | [diff] [blame] | 286 | #ifdef ARCH_NEEDS_KMAP_HIGH_GET |
| 287 | /** |
| 288 | * kmap_high_get - pin a highmem page into memory |
| 289 | * @page: &struct page to pin |
| 290 | * |
| 291 | * Returns the page's current virtual memory address, or NULL if no mapping |
Uwe Kleine-König | 5e39df5 | 2010-01-25 21:38:09 +0100 | [diff] [blame] | 292 | * exists. If and only if a non null address is returned then a |
Nicolas Pitre | 3297e76 | 2009-03-04 22:49:41 -0500 | [diff] [blame] | 293 | * matching call to kunmap_high() is necessary. |
| 294 | * |
| 295 | * This can be called from any context. |
| 296 | */ |
| 297 | void *kmap_high_get(struct page *page) |
| 298 | { |
| 299 | unsigned long vaddr, flags; |
| 300 | |
| 301 | lock_kmap_any(flags); |
| 302 | vaddr = (unsigned long)page_address(page); |
| 303 | if (vaddr) { |
| 304 | BUG_ON(pkmap_count[PKMAP_NR(vaddr)] < 1); |
| 305 | pkmap_count[PKMAP_NR(vaddr)]++; |
| 306 | } |
| 307 | unlock_kmap_any(flags); |
| 308 | return (void*) vaddr; |
| 309 | } |
| 310 | #endif |
| 311 | |
Randy Dunlap | 77f6078 | 2008-03-19 17:00:42 -0700 | [diff] [blame] | 312 | /** |
Li Haifeng | 4e9dc5d | 2011-10-31 17:09:09 -0700 | [diff] [blame] | 313 | * kunmap_high - unmap a highmem page into memory |
Randy Dunlap | 77f6078 | 2008-03-19 17:00:42 -0700 | [diff] [blame] | 314 | * @page: &struct page to unmap |
Nicolas Pitre | 3297e76 | 2009-03-04 22:49:41 -0500 | [diff] [blame] | 315 | * |
| 316 | * If ARCH_NEEDS_KMAP_HIGH_GET is not defined then this may be called |
| 317 | * only from user context. |
Randy Dunlap | 77f6078 | 2008-03-19 17:00:42 -0700 | [diff] [blame] | 318 | */ |
Harvey Harrison | 920c7a5 | 2008-02-04 22:29:26 -0800 | [diff] [blame] | 319 | void kunmap_high(struct page *page) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 320 | { |
| 321 | unsigned long vaddr; |
| 322 | unsigned long nr; |
Nicolas Pitre | 3297e76 | 2009-03-04 22:49:41 -0500 | [diff] [blame] | 323 | unsigned long flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 324 | int need_wakeup; |
Max Filippov | 15de36a | 2014-08-06 16:08:23 -0700 | [diff] [blame] | 325 | unsigned int color = get_pkmap_color(page); |
| 326 | wait_queue_head_t *pkmap_map_wait; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 327 | |
Nicolas Pitre | 3297e76 | 2009-03-04 22:49:41 -0500 | [diff] [blame] | 328 | lock_kmap_any(flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 329 | vaddr = (unsigned long)page_address(page); |
Eric Sesterhenn | 75babca | 2006-04-02 13:47:35 +0200 | [diff] [blame] | 330 | BUG_ON(!vaddr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 331 | nr = PKMAP_NR(vaddr); |
| 332 | |
| 333 | /* |
| 334 | * A count must never go down to zero |
| 335 | * without a TLB flush! |
| 336 | */ |
| 337 | need_wakeup = 0; |
| 338 | switch (--pkmap_count[nr]) { |
| 339 | case 0: |
| 340 | BUG(); |
| 341 | case 1: |
| 342 | /* |
| 343 | * Avoid an unnecessary wake_up() function call. |
| 344 | * The common case is pkmap_count[] == 1, but |
| 345 | * no waiters. |
| 346 | * The tasks queued in the wait-queue are guarded |
| 347 | * by both the lock in the wait-queue-head and by |
| 348 | * the kmap_lock. As the kmap_lock is held here, |
| 349 | * no need for the wait-queue-head's lock. Simply |
| 350 | * test if the queue is empty. |
| 351 | */ |
Max Filippov | 15de36a | 2014-08-06 16:08:23 -0700 | [diff] [blame] | 352 | pkmap_map_wait = get_pkmap_wait_queue_head(color); |
| 353 | need_wakeup = waitqueue_active(pkmap_map_wait); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 354 | } |
Nicolas Pitre | 3297e76 | 2009-03-04 22:49:41 -0500 | [diff] [blame] | 355 | unlock_kmap_any(flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 356 | |
| 357 | /* do wake-up, if needed, race-free outside of the spin lock */ |
| 358 | if (need_wakeup) |
Max Filippov | 15de36a | 2014-08-06 16:08:23 -0700 | [diff] [blame] | 359 | wake_up(pkmap_map_wait); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 360 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 361 | EXPORT_SYMBOL(kunmap_high); |
Matthew Wilcox (Oracle) | 0060ef3 | 2020-12-14 19:12:59 -0800 | [diff] [blame] | 362 | |
| 363 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
| 364 | void zero_user_segments(struct page *page, unsigned start1, unsigned end1, |
| 365 | unsigned start2, unsigned end2) |
| 366 | { |
| 367 | unsigned int i; |
| 368 | |
| 369 | BUG_ON(end1 > page_size(page) || end2 > page_size(page)); |
| 370 | |
OGAWA Hirofumi | 184cee5 | 2021-03-12 21:07:37 -0800 | [diff] [blame] | 371 | if (start1 >= end1) |
| 372 | start1 = end1 = 0; |
| 373 | if (start2 >= end2) |
| 374 | start2 = end2 = 0; |
| 375 | |
Matthew Wilcox (Oracle) | 0060ef3 | 2020-12-14 19:12:59 -0800 | [diff] [blame] | 376 | for (i = 0; i < compound_nr(page); i++) { |
| 377 | void *kaddr = NULL; |
| 378 | |
Matthew Wilcox (Oracle) | 0060ef3 | 2020-12-14 19:12:59 -0800 | [diff] [blame] | 379 | if (start1 >= PAGE_SIZE) { |
| 380 | start1 -= PAGE_SIZE; |
| 381 | end1 -= PAGE_SIZE; |
| 382 | } else { |
| 383 | unsigned this_end = min_t(unsigned, end1, PAGE_SIZE); |
| 384 | |
OGAWA Hirofumi | 184cee5 | 2021-03-12 21:07:37 -0800 | [diff] [blame] | 385 | if (end1 > start1) { |
| 386 | kaddr = kmap_atomic(page + i); |
Matthew Wilcox (Oracle) | 0060ef3 | 2020-12-14 19:12:59 -0800 | [diff] [blame] | 387 | memset(kaddr + start1, 0, this_end - start1); |
OGAWA Hirofumi | 184cee5 | 2021-03-12 21:07:37 -0800 | [diff] [blame] | 388 | } |
Matthew Wilcox (Oracle) | 0060ef3 | 2020-12-14 19:12:59 -0800 | [diff] [blame] | 389 | end1 -= this_end; |
| 390 | start1 = 0; |
| 391 | } |
| 392 | |
| 393 | if (start2 >= PAGE_SIZE) { |
| 394 | start2 -= PAGE_SIZE; |
| 395 | end2 -= PAGE_SIZE; |
| 396 | } else { |
| 397 | unsigned this_end = min_t(unsigned, end2, PAGE_SIZE); |
| 398 | |
OGAWA Hirofumi | 184cee5 | 2021-03-12 21:07:37 -0800 | [diff] [blame] | 399 | if (end2 > start2) { |
| 400 | if (!kaddr) |
| 401 | kaddr = kmap_atomic(page + i); |
Matthew Wilcox (Oracle) | 0060ef3 | 2020-12-14 19:12:59 -0800 | [diff] [blame] | 402 | memset(kaddr + start2, 0, this_end - start2); |
OGAWA Hirofumi | 184cee5 | 2021-03-12 21:07:37 -0800 | [diff] [blame] | 403 | } |
Matthew Wilcox (Oracle) | 0060ef3 | 2020-12-14 19:12:59 -0800 | [diff] [blame] | 404 | end2 -= this_end; |
| 405 | start2 = 0; |
| 406 | } |
| 407 | |
| 408 | if (kaddr) { |
| 409 | kunmap_atomic(kaddr); |
| 410 | flush_dcache_page(page + i); |
| 411 | } |
| 412 | |
| 413 | if (!end1 && !end2) |
| 414 | break; |
| 415 | } |
| 416 | |
| 417 | BUG_ON((start1 | start2 | end1 | end2) != 0); |
| 418 | } |
| 419 | EXPORT_SYMBOL(zero_user_segments); |
| 420 | #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ |
Thomas Gleixner | 298fa1a | 2020-11-03 10:27:18 +0100 | [diff] [blame] | 421 | #endif /* CONFIG_HIGHMEM */ |
| 422 | |
| 423 | #ifdef CONFIG_KMAP_LOCAL |
| 424 | |
| 425 | #include <asm/kmap_size.h> |
| 426 | |
Thomas Gleixner | 389755c | 2020-11-03 10:27:19 +0100 | [diff] [blame] | 427 | /* |
Thomas Gleixner | 6e799cb | 2020-11-18 20:48:39 +0100 | [diff] [blame] | 428 | * With DEBUG_KMAP_LOCAL the stack depth is doubled and every second |
Thomas Gleixner | 389755c | 2020-11-03 10:27:19 +0100 | [diff] [blame] | 429 | * slot is unused which acts as a guard page |
| 430 | */ |
Thomas Gleixner | 6e799cb | 2020-11-18 20:48:39 +0100 | [diff] [blame] | 431 | #ifdef CONFIG_DEBUG_KMAP_LOCAL |
Thomas Gleixner | 389755c | 2020-11-03 10:27:19 +0100 | [diff] [blame] | 432 | # define KM_INCR 2 |
| 433 | #else |
| 434 | # define KM_INCR 1 |
| 435 | #endif |
| 436 | |
Thomas Gleixner | 298fa1a | 2020-11-03 10:27:18 +0100 | [diff] [blame] | 437 | static inline int kmap_local_idx_push(void) |
| 438 | { |
Thomas Gleixner | 298fa1a | 2020-11-03 10:27:18 +0100 | [diff] [blame] | 439 | WARN_ON_ONCE(in_irq() && !irqs_disabled()); |
Thomas Gleixner | 5fbda3e | 2020-11-18 20:48:43 +0100 | [diff] [blame] | 440 | current->kmap_ctrl.idx += KM_INCR; |
| 441 | BUG_ON(current->kmap_ctrl.idx >= KM_MAX_IDX); |
| 442 | return current->kmap_ctrl.idx - 1; |
Thomas Gleixner | 298fa1a | 2020-11-03 10:27:18 +0100 | [diff] [blame] | 443 | } |
| 444 | |
| 445 | static inline int kmap_local_idx(void) |
| 446 | { |
Thomas Gleixner | 5fbda3e | 2020-11-18 20:48:43 +0100 | [diff] [blame] | 447 | return current->kmap_ctrl.idx - 1; |
Thomas Gleixner | 298fa1a | 2020-11-03 10:27:18 +0100 | [diff] [blame] | 448 | } |
| 449 | |
| 450 | static inline void kmap_local_idx_pop(void) |
| 451 | { |
Thomas Gleixner | 5fbda3e | 2020-11-18 20:48:43 +0100 | [diff] [blame] | 452 | current->kmap_ctrl.idx -= KM_INCR; |
| 453 | BUG_ON(current->kmap_ctrl.idx < 0); |
Thomas Gleixner | 298fa1a | 2020-11-03 10:27:18 +0100 | [diff] [blame] | 454 | } |
| 455 | |
| 456 | #ifndef arch_kmap_local_post_map |
| 457 | # define arch_kmap_local_post_map(vaddr, pteval) do { } while (0) |
| 458 | #endif |
Thomas Gleixner | 3c1016b | 2020-11-03 10:27:31 +0100 | [diff] [blame] | 459 | |
Thomas Gleixner | 298fa1a | 2020-11-03 10:27:18 +0100 | [diff] [blame] | 460 | #ifndef arch_kmap_local_pre_unmap |
| 461 | # define arch_kmap_local_pre_unmap(vaddr) do { } while (0) |
| 462 | #endif |
| 463 | |
| 464 | #ifndef arch_kmap_local_post_unmap |
| 465 | # define arch_kmap_local_post_unmap(vaddr) do { } while (0) |
| 466 | #endif |
| 467 | |
| 468 | #ifndef arch_kmap_local_map_idx |
| 469 | #define arch_kmap_local_map_idx(idx, pfn) kmap_local_calc_idx(idx) |
| 470 | #endif |
| 471 | |
| 472 | #ifndef arch_kmap_local_unmap_idx |
| 473 | #define arch_kmap_local_unmap_idx(idx, vaddr) kmap_local_calc_idx(idx) |
| 474 | #endif |
| 475 | |
| 476 | #ifndef arch_kmap_local_high_get |
| 477 | static inline void *arch_kmap_local_high_get(struct page *page) |
| 478 | { |
| 479 | return NULL; |
| 480 | } |
| 481 | #endif |
| 482 | |
Thomas Gleixner | a1dce7f | 2021-01-23 21:02:02 -0800 | [diff] [blame] | 483 | #ifndef arch_kmap_local_set_pte |
| 484 | #define arch_kmap_local_set_pte(mm, vaddr, ptep, ptev) \ |
| 485 | set_pte_at(mm, vaddr, ptep, ptev) |
| 486 | #endif |
| 487 | |
Thomas Gleixner | 298fa1a | 2020-11-03 10:27:18 +0100 | [diff] [blame] | 488 | /* Unmap a local mapping which was obtained by kmap_high_get() */ |
Thomas Gleixner | 2a656ca | 2020-11-12 11:59:32 +0100 | [diff] [blame] | 489 | static inline bool kmap_high_unmap_local(unsigned long vaddr) |
Thomas Gleixner | 298fa1a | 2020-11-03 10:27:18 +0100 | [diff] [blame] | 490 | { |
| 491 | #ifdef ARCH_NEEDS_KMAP_HIGH_GET |
Thomas Gleixner | 2a656ca | 2020-11-12 11:59:32 +0100 | [diff] [blame] | 492 | if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) { |
Thomas Gleixner | 298fa1a | 2020-11-03 10:27:18 +0100 | [diff] [blame] | 493 | kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)])); |
Thomas Gleixner | 2a656ca | 2020-11-12 11:59:32 +0100 | [diff] [blame] | 494 | return true; |
| 495 | } |
Thomas Gleixner | 298fa1a | 2020-11-03 10:27:18 +0100 | [diff] [blame] | 496 | #endif |
Thomas Gleixner | 2a656ca | 2020-11-12 11:59:32 +0100 | [diff] [blame] | 497 | return false; |
Thomas Gleixner | 298fa1a | 2020-11-03 10:27:18 +0100 | [diff] [blame] | 498 | } |
| 499 | |
| 500 | static inline int kmap_local_calc_idx(int idx) |
| 501 | { |
| 502 | return idx + KM_MAX_IDX * smp_processor_id(); |
| 503 | } |
| 504 | |
| 505 | static pte_t *__kmap_pte; |
| 506 | |
| 507 | static pte_t *kmap_get_pte(void) |
| 508 | { |
| 509 | if (!__kmap_pte) |
| 510 | __kmap_pte = virt_to_kpte(__fix_to_virt(FIX_KMAP_BEGIN)); |
| 511 | return __kmap_pte; |
| 512 | } |
| 513 | |
| 514 | void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot) |
| 515 | { |
| 516 | pte_t pteval, *kmap_pte = kmap_get_pte(); |
| 517 | unsigned long vaddr; |
| 518 | int idx; |
| 519 | |
Thomas Gleixner | f3ba3c7 | 2020-11-18 20:48:44 +0100 | [diff] [blame] | 520 | /* |
| 521 | * Disable migration so resulting virtual address is stable |
| 522 | * accross preemption. |
| 523 | */ |
| 524 | migrate_disable(); |
Thomas Gleixner | 298fa1a | 2020-11-03 10:27:18 +0100 | [diff] [blame] | 525 | preempt_disable(); |
| 526 | idx = arch_kmap_local_map_idx(kmap_local_idx_push(), pfn); |
| 527 | vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); |
| 528 | BUG_ON(!pte_none(*(kmap_pte - idx))); |
| 529 | pteval = pfn_pte(pfn, prot); |
Thomas Gleixner | a1dce7f | 2021-01-23 21:02:02 -0800 | [diff] [blame] | 530 | arch_kmap_local_set_pte(&init_mm, vaddr, kmap_pte - idx, pteval); |
Thomas Gleixner | 298fa1a | 2020-11-03 10:27:18 +0100 | [diff] [blame] | 531 | arch_kmap_local_post_map(vaddr, pteval); |
Thomas Gleixner | 5fbda3e | 2020-11-18 20:48:43 +0100 | [diff] [blame] | 532 | current->kmap_ctrl.pteval[kmap_local_idx()] = pteval; |
Thomas Gleixner | 298fa1a | 2020-11-03 10:27:18 +0100 | [diff] [blame] | 533 | preempt_enable(); |
| 534 | |
| 535 | return (void *)vaddr; |
| 536 | } |
| 537 | EXPORT_SYMBOL_GPL(__kmap_local_pfn_prot); |
| 538 | |
| 539 | void *__kmap_local_page_prot(struct page *page, pgprot_t prot) |
| 540 | { |
| 541 | void *kmap; |
| 542 | |
Thomas Gleixner | 0e91a0c | 2020-11-18 20:48:40 +0100 | [diff] [blame] | 543 | /* |
| 544 | * To broaden the usage of the actual kmap_local() machinery always map |
| 545 | * pages when debugging is enabled and the architecture has no problems |
| 546 | * with alias mappings. |
| 547 | */ |
| 548 | if (!IS_ENABLED(CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP) && !PageHighMem(page)) |
Thomas Gleixner | 298fa1a | 2020-11-03 10:27:18 +0100 | [diff] [blame] | 549 | return page_address(page); |
| 550 | |
| 551 | /* Try kmap_high_get() if architecture has it enabled */ |
| 552 | kmap = arch_kmap_local_high_get(page); |
| 553 | if (kmap) |
| 554 | return kmap; |
| 555 | |
| 556 | return __kmap_local_pfn_prot(page_to_pfn(page), prot); |
| 557 | } |
| 558 | EXPORT_SYMBOL(__kmap_local_page_prot); |
| 559 | |
| 560 | void kunmap_local_indexed(void *vaddr) |
| 561 | { |
| 562 | unsigned long addr = (unsigned long) vaddr & PAGE_MASK; |
| 563 | pte_t *kmap_pte = kmap_get_pte(); |
| 564 | int idx; |
| 565 | |
| 566 | if (addr < __fix_to_virt(FIX_KMAP_END) || |
| 567 | addr > __fix_to_virt(FIX_KMAP_BEGIN)) { |
Thomas Gleixner | 0e91a0c | 2020-11-18 20:48:40 +0100 | [diff] [blame] | 568 | if (IS_ENABLED(CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP)) { |
| 569 | /* This _should_ never happen! See above. */ |
| 570 | WARN_ON_ONCE(1); |
| 571 | return; |
| 572 | } |
Thomas Gleixner | 2a656ca | 2020-11-12 11:59:32 +0100 | [diff] [blame] | 573 | /* |
| 574 | * Handle mappings which were obtained by kmap_high_get() |
| 575 | * first as the virtual address of such mappings is below |
| 576 | * PAGE_OFFSET. Warn for all other addresses which are in |
| 577 | * the user space part of the virtual address space. |
| 578 | */ |
| 579 | if (!kmap_high_unmap_local(addr)) |
| 580 | WARN_ON_ONCE(addr < PAGE_OFFSET); |
Thomas Gleixner | 298fa1a | 2020-11-03 10:27:18 +0100 | [diff] [blame] | 581 | return; |
| 582 | } |
| 583 | |
| 584 | preempt_disable(); |
| 585 | idx = arch_kmap_local_unmap_idx(kmap_local_idx(), addr); |
| 586 | WARN_ON_ONCE(addr != __fix_to_virt(FIX_KMAP_BEGIN + idx)); |
| 587 | |
| 588 | arch_kmap_local_pre_unmap(addr); |
| 589 | pte_clear(&init_mm, addr, kmap_pte - idx); |
| 590 | arch_kmap_local_post_unmap(addr); |
Thomas Gleixner | 5fbda3e | 2020-11-18 20:48:43 +0100 | [diff] [blame] | 591 | current->kmap_ctrl.pteval[kmap_local_idx()] = __pte(0); |
Thomas Gleixner | 298fa1a | 2020-11-03 10:27:18 +0100 | [diff] [blame] | 592 | kmap_local_idx_pop(); |
| 593 | preempt_enable(); |
Thomas Gleixner | f3ba3c7 | 2020-11-18 20:48:44 +0100 | [diff] [blame] | 594 | migrate_enable(); |
Thomas Gleixner | 298fa1a | 2020-11-03 10:27:18 +0100 | [diff] [blame] | 595 | } |
| 596 | EXPORT_SYMBOL(kunmap_local_indexed); |
Thomas Gleixner | 5fbda3e | 2020-11-18 20:48:43 +0100 | [diff] [blame] | 597 | |
| 598 | /* |
| 599 | * Invoked before switch_to(). This is safe even when during or after |
| 600 | * clearing the maps an interrupt which needs a kmap_local happens because |
| 601 | * the task::kmap_ctrl.idx is not modified by the unmapping code so a |
| 602 | * nested kmap_local will use the next unused index and restore the index |
| 603 | * on unmap. The already cleared kmaps of the outgoing task are irrelevant |
| 604 | * because the interrupt context does not know about them. The same applies |
| 605 | * when scheduling back in for an interrupt which happens before the |
| 606 | * restore is complete. |
| 607 | */ |
| 608 | void __kmap_local_sched_out(void) |
| 609 | { |
| 610 | struct task_struct *tsk = current; |
| 611 | pte_t *kmap_pte = kmap_get_pte(); |
| 612 | int i; |
| 613 | |
| 614 | /* Clear kmaps */ |
| 615 | for (i = 0; i < tsk->kmap_ctrl.idx; i++) { |
| 616 | pte_t pteval = tsk->kmap_ctrl.pteval[i]; |
| 617 | unsigned long addr; |
| 618 | int idx; |
| 619 | |
| 620 | /* With debug all even slots are unmapped and act as guard */ |
Ira Weiny | 487cfad | 2021-03-24 21:37:53 -0700 | [diff] [blame] | 621 | if (IS_ENABLED(CONFIG_DEBUG_KMAP_LOCAL) && !(i & 0x01)) { |
Thomas Gleixner | 5fbda3e | 2020-11-18 20:48:43 +0100 | [diff] [blame] | 622 | WARN_ON_ONCE(!pte_none(pteval)); |
| 623 | continue; |
| 624 | } |
| 625 | if (WARN_ON_ONCE(pte_none(pteval))) |
| 626 | continue; |
| 627 | |
| 628 | /* |
| 629 | * This is a horrible hack for XTENSA to calculate the |
| 630 | * coloured PTE index. Uses the PFN encoded into the pteval |
| 631 | * and the map index calculation because the actual mapped |
| 632 | * virtual address is not stored in task::kmap_ctrl. |
| 633 | * For any sane architecture this is optimized out. |
| 634 | */ |
| 635 | idx = arch_kmap_local_map_idx(i, pte_pfn(pteval)); |
| 636 | |
| 637 | addr = __fix_to_virt(FIX_KMAP_BEGIN + idx); |
| 638 | arch_kmap_local_pre_unmap(addr); |
| 639 | pte_clear(&init_mm, addr, kmap_pte - idx); |
| 640 | arch_kmap_local_post_unmap(addr); |
| 641 | } |
| 642 | } |
| 643 | |
| 644 | void __kmap_local_sched_in(void) |
| 645 | { |
| 646 | struct task_struct *tsk = current; |
| 647 | pte_t *kmap_pte = kmap_get_pte(); |
| 648 | int i; |
| 649 | |
| 650 | /* Restore kmaps */ |
| 651 | for (i = 0; i < tsk->kmap_ctrl.idx; i++) { |
| 652 | pte_t pteval = tsk->kmap_ctrl.pteval[i]; |
| 653 | unsigned long addr; |
| 654 | int idx; |
| 655 | |
| 656 | /* With debug all even slots are unmapped and act as guard */ |
Ira Weiny | 487cfad | 2021-03-24 21:37:53 -0700 | [diff] [blame] | 657 | if (IS_ENABLED(CONFIG_DEBUG_KMAP_LOCAL) && !(i & 0x01)) { |
Thomas Gleixner | 5fbda3e | 2020-11-18 20:48:43 +0100 | [diff] [blame] | 658 | WARN_ON_ONCE(!pte_none(pteval)); |
| 659 | continue; |
| 660 | } |
| 661 | if (WARN_ON_ONCE(pte_none(pteval))) |
| 662 | continue; |
| 663 | |
| 664 | /* See comment in __kmap_local_sched_out() */ |
| 665 | idx = arch_kmap_local_map_idx(i, pte_pfn(pteval)); |
| 666 | addr = __fix_to_virt(FIX_KMAP_BEGIN + idx); |
| 667 | set_pte_at(&init_mm, addr, kmap_pte - idx, pteval); |
| 668 | arch_kmap_local_post_map(addr, pteval); |
| 669 | } |
| 670 | } |
| 671 | |
| 672 | void kmap_local_fork(struct task_struct *tsk) |
| 673 | { |
| 674 | if (WARN_ON_ONCE(tsk->kmap_ctrl.idx)) |
| 675 | memset(&tsk->kmap_ctrl, 0, sizeof(tsk->kmap_ctrl)); |
| 676 | } |
| 677 | |
Thomas Gleixner | 298fa1a | 2020-11-03 10:27:18 +0100 | [diff] [blame] | 678 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 679 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 680 | #if defined(HASHED_PAGE_VIRTUAL) |
| 681 | |
| 682 | #define PA_HASH_ORDER 7 |
| 683 | |
| 684 | /* |
| 685 | * Describes one page->virtual association |
| 686 | */ |
| 687 | struct page_address_map { |
| 688 | struct page *page; |
| 689 | void *virtual; |
| 690 | struct list_head list; |
| 691 | }; |
| 692 | |
Joonsoo Kim | a354e2c | 2012-12-11 16:01:23 -0800 | [diff] [blame] | 693 | static struct page_address_map page_address_maps[LAST_PKMAP]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 694 | |
| 695 | /* |
| 696 | * Hash table bucket |
| 697 | */ |
| 698 | static struct page_address_slot { |
| 699 | struct list_head lh; /* List of page_address_maps */ |
| 700 | spinlock_t lock; /* Protect this bucket's list */ |
| 701 | } ____cacheline_aligned_in_smp page_address_htable[1<<PA_HASH_ORDER]; |
| 702 | |
Ian Campbell | f991879 | 2011-08-17 13:45:09 +0100 | [diff] [blame] | 703 | static struct page_address_slot *page_slot(const struct page *page) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 704 | { |
| 705 | return &page_address_htable[hash_ptr(page, PA_HASH_ORDER)]; |
| 706 | } |
| 707 | |
Randy Dunlap | 77f6078 | 2008-03-19 17:00:42 -0700 | [diff] [blame] | 708 | /** |
| 709 | * page_address - get the mapped virtual address of a page |
| 710 | * @page: &struct page to get the virtual address of |
| 711 | * |
| 712 | * Returns the page's virtual address. |
| 713 | */ |
Ian Campbell | f991879 | 2011-08-17 13:45:09 +0100 | [diff] [blame] | 714 | void *page_address(const struct page *page) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 715 | { |
| 716 | unsigned long flags; |
| 717 | void *ret; |
| 718 | struct page_address_slot *pas; |
| 719 | |
| 720 | if (!PageHighMem(page)) |
| 721 | return lowmem_page_address(page); |
| 722 | |
| 723 | pas = page_slot(page); |
| 724 | ret = NULL; |
| 725 | spin_lock_irqsave(&pas->lock, flags); |
| 726 | if (!list_empty(&pas->lh)) { |
| 727 | struct page_address_map *pam; |
| 728 | |
| 729 | list_for_each_entry(pam, &pas->lh, list) { |
| 730 | if (pam->page == page) { |
| 731 | ret = pam->virtual; |
| 732 | goto done; |
| 733 | } |
| 734 | } |
| 735 | } |
| 736 | done: |
| 737 | spin_unlock_irqrestore(&pas->lock, flags); |
| 738 | return ret; |
| 739 | } |
| 740 | |
| 741 | EXPORT_SYMBOL(page_address); |
| 742 | |
Randy Dunlap | 77f6078 | 2008-03-19 17:00:42 -0700 | [diff] [blame] | 743 | /** |
| 744 | * set_page_address - set a page's virtual address |
| 745 | * @page: &struct page to set |
| 746 | * @virtual: virtual address to use |
| 747 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 748 | void set_page_address(struct page *page, void *virtual) |
| 749 | { |
| 750 | unsigned long flags; |
| 751 | struct page_address_slot *pas; |
| 752 | struct page_address_map *pam; |
| 753 | |
| 754 | BUG_ON(!PageHighMem(page)); |
| 755 | |
| 756 | pas = page_slot(page); |
| 757 | if (virtual) { /* Add */ |
Joonsoo Kim | a354e2c | 2012-12-11 16:01:23 -0800 | [diff] [blame] | 758 | pam = &page_address_maps[PKMAP_NR((unsigned long)virtual)]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 759 | pam->page = page; |
| 760 | pam->virtual = virtual; |
| 761 | |
| 762 | spin_lock_irqsave(&pas->lock, flags); |
| 763 | list_add_tail(&pam->list, &pas->lh); |
| 764 | spin_unlock_irqrestore(&pas->lock, flags); |
| 765 | } else { /* Remove */ |
| 766 | spin_lock_irqsave(&pas->lock, flags); |
| 767 | list_for_each_entry(pam, &pas->lh, list) { |
| 768 | if (pam->page == page) { |
| 769 | list_del(&pam->list); |
| 770 | spin_unlock_irqrestore(&pas->lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 771 | goto done; |
| 772 | } |
| 773 | } |
| 774 | spin_unlock_irqrestore(&pas->lock, flags); |
| 775 | } |
| 776 | done: |
| 777 | return; |
| 778 | } |
| 779 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 780 | void __init page_address_init(void) |
| 781 | { |
| 782 | int i; |
| 783 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 784 | for (i = 0; i < ARRAY_SIZE(page_address_htable); i++) { |
| 785 | INIT_LIST_HEAD(&page_address_htable[i].lh); |
| 786 | spin_lock_init(&page_address_htable[i].lock); |
| 787 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 788 | } |
| 789 | |
Ira Weiny | 955cc77 | 2020-10-15 20:09:52 -0700 | [diff] [blame] | 790 | #endif /* defined(HASHED_PAGE_VIRTUAL) */ |