1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright 2007 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 /* 26 * Copyright (c) 2014 by Delphix. All rights reserved. 27 */ 28 29 #ifndef _VM_HTABLE_H 30 #define _VM_HTABLE_H 31 32 #ifdef __cplusplus 33 extern "C" { 34 #endif 35 36 #if defined(__GNUC__) && defined(_ASM_INLINES) && defined(_KERNEL) 37 #include <asm/htable.h> 38 #endif 39 40 extern void atomic_andb(uint8_t *addr, uint8_t value); 41 extern void atomic_orb(uint8_t *addr, uint8_t value); 42 extern void atomic_inc16(uint16_t *addr); 43 extern void atomic_dec16(uint16_t *addr); 44 extern void mmu_tlbflush_entry(caddr_t addr); 45 46 /* 47 * Each hardware page table has an htable_t describing it. 48 * 49 * We use a reference counter mechanism to detect when we can free an htable. 50 * In the implmentation the reference count is split into 2 separate counters: 51 * 52 * ht_busy is a traditional reference count of uses of the htable pointer 53 * 54 * ht_valid_cnt is a count of how references are implied by valid PTE/PTP 55 * entries in the pagetable 56 * 57 * ht_busy is only incremented by htable_lookup() or htable_create() 58 * while holding the appropriate hash_table mutex. While installing a new 59 * valid PTE or PTP, in order to increment ht_valid_cnt a thread must have 60 * done an htable_lookup() or htable_create() but not the htable_release yet. 61 * 62 * htable_release(), while holding the mutex, can know that if 63 * busy == 1 and valid_cnt == 0, the htable can be free'd. 64 * 65 * The fields have been ordered to make htable_lookup() fast. Hence, 66 * ht_hat, ht_vaddr, ht_level and ht_next need to be clustered together. 67 */ 68 struct htable { 69 struct htable *ht_next; /* forward link for hash table */ 70 struct hat *ht_hat; /* hat this mapping comes from */ 71 uintptr_t ht_vaddr; /* virt addr at start of this table */ 72 int8_t ht_level; /* page table level: 0=4K, 1=2M, ... */ 73 uint8_t ht_flags; /* see below */ 74 int16_t ht_busy; /* implements locking protocol */ 75 int16_t ht_valid_cnt; /* # of valid entries in this table */ 76 uint32_t ht_lock_cnt; /* # of locked entries in this table */ 77 /* never used for kernel hat */ 78 pfn_t ht_pfn; /* pfn of page of the pagetable */ 79 struct htable *ht_prev; /* backward link for hash table */ 80 struct htable *ht_parent; /* htable that points to this htable */ 81 struct htable *ht_shares; /* for HTABLE_SHARED_PFN only */ 82 }; 83 typedef struct htable htable_t; 84 85 /* 86 * Flags values for htable ht_flags field: 87 * 88 * HTABLE_VLP - this is the top level htable of a VLP HAT. 89 * 90 * HTABLE_SHARED_PFN - this htable had its PFN assigned from sharing another 91 * htable. Used by hat_share() for ISM. 92 */ 93 #define HTABLE_VLP (0x01) 94 #define HTABLE_SHARED_PFN (0x02) 95 96 /* 97 * The htable hash table hashing function. The 28 is so that high 98 * order bits are include in the hash index to skew the wrap 99 * around of addresses. Even though the hash buckets are stored per 100 * hat we include the value of hat pointer in the hash function so 101 * that the secondary hash for the htable mutex winds up begin different in 102 * every address space. 103 */ 104 #define HTABLE_HASH(hat, va, lvl) \ 105 ((((va) >> LEVEL_SHIFT(1)) + ((va) >> 28) + (lvl) + \ 106 ((uintptr_t)(hat) >> 4)) & ((hat)->hat_num_hash - 1)) 107 108 /* 109 * Each CPU gets a unique hat_cpu_info structure in cpu_hat_info. 110 */ 111 struct hat_cpu_info { 112 kmutex_t hci_mutex; /* mutex to ensure sequential usage */ 113 #if defined(__amd64) 114 pfn_t hci_vlp_pfn; /* pfn of hci_vlp_l3ptes */ 115 x86pte_t *hci_vlp_l3ptes; /* VLP Level==3 pagetable (top) */ 116 x86pte_t *hci_vlp_l2ptes; /* VLP Level==2 pagetable */ 117 #endif /* __amd64 */ 118 }; 119 120 121 /* 122 * Compute the last page aligned VA mapped by an htable. 123 * 124 * Given a va and a level, compute the virtual address of the start of the 125 * next page at that level. 126 * 127 * XX64 - The check for the VA hole needs to be better generalized. 128 */ 129 #if defined(__amd64) 130 #define HTABLE_NUM_PTES(ht) (((ht)->ht_flags & HTABLE_VLP) ? 4 : 512) 131 132 #define HTABLE_LAST_PAGE(ht) \ 133 ((ht)->ht_level == mmu.max_level ? ((uintptr_t)0UL - MMU_PAGESIZE) :\ 134 ((ht)->ht_vaddr - MMU_PAGESIZE + \ 135 ((uintptr_t)HTABLE_NUM_PTES(ht) << LEVEL_SHIFT((ht)->ht_level)))) 136 137 #define NEXT_ENTRY_VA(va, l) \ 138 ((va & LEVEL_MASK(l)) + LEVEL_SIZE(l) == mmu.hole_start ? \ 139 mmu.hole_end : (va & LEVEL_MASK(l)) + LEVEL_SIZE(l)) 140 141 #elif defined(__i386) 142 143 #define HTABLE_NUM_PTES(ht) \ 144 (!mmu.pae_hat ? 1024 : ((ht)->ht_level == 2 ? 4 : 512)) 145 146 #define HTABLE_LAST_PAGE(ht) ((ht)->ht_vaddr - MMU_PAGESIZE + \ 147 ((uintptr_t)HTABLE_NUM_PTES(ht) << LEVEL_SHIFT((ht)->ht_level))) 148 149 #define NEXT_ENTRY_VA(va, l) ((va & LEVEL_MASK(l)) + LEVEL_SIZE(l)) 150 151 #endif 152 153 #if defined(_KERNEL) 154 155 /* 156 * initialization function called from hat_init() 157 */ 158 extern void htable_init(void); 159 160 /* 161 * Functions to lookup, or "lookup and create", the htable corresponding 162 * to the virtual address "vaddr" in the "hat" at the given "level" of 163 * page tables. htable_lookup() may return NULL if no such entry exists. 164 * 165 * On return the given htable is marked busy (a shared lock) - this prevents 166 * the htable from being stolen or freed) until htable_release() is called. 167 * 168 * If kalloc_flag is set on an htable_create() we can't call kmem allocation 169 * routines for this htable, since it's for the kernel hat itself. 170 * 171 * htable_acquire() is used when an htable pointer has been extracted from 172 * an hment and we need to get a reference to the htable. 173 */ 174 extern htable_t *htable_lookup(struct hat *hat, uintptr_t vaddr, level_t level); 175 extern htable_t *htable_create(struct hat *hat, uintptr_t vaddr, level_t level, 176 htable_t *shared); 177 extern void htable_acquire(htable_t *); 178 179 extern void htable_release(htable_t *ht); 180 extern void htable_destroy(htable_t *ht); 181 182 /* 183 * Code to free all remaining htables for a hat. Called after the hat is no 184 * longer in use by any thread. 185 */ 186 extern void htable_purge_hat(struct hat *hat); 187 188 /* 189 * Find the htable, page table entry index, and PTE of the given virtual 190 * address. If not found returns NULL. When found, returns the htable_t *, 191 * sets entry, and has a hold on the htable. 192 */ 193 extern htable_t *htable_getpte(struct hat *, uintptr_t, uint_t *, x86pte_t *, 194 level_t); 195 196 /* 197 * Similar to hat_getpte(), except that this only succeeds if a valid 198 * page mapping is present. 199 */ 200 extern htable_t *htable_getpage(struct hat *hat, uintptr_t va, uint_t *entry); 201 202 /* 203 * Called to allocate initial/additional htables for reserve. 204 */ 205 extern void htable_initial_reserve(uint_t); 206 extern void htable_reserve(uint_t); 207 208 /* 209 * Used to readjust the htable reserve after the reserve list has been used. 210 * Also called after boot to release left over boot reserves. 211 */ 212 extern void htable_adjust_reserve(void); 213 214 /* 215 * return number of bytes mapped by all the htables in a given hat 216 */ 217 extern size_t htable_mapped(struct hat *); 218 219 220 /* 221 * Attach initial pagetables as htables 222 */ 223 extern void htable_attach(struct hat *, uintptr_t, level_t, struct htable *, 224 pfn_t); 225 226 /* 227 * Routine to find the next populated htable at or above a given virtual 228 * address. Can specify an upper limit, or HTABLE_WALK_TO_END to indicate 229 * that it should search the entire address space. Similar to 230 * hat_getpte(), but used for walking through address ranges. It can be 231 * used like this: 232 * 233 * va = ... 234 * ht = NULL; 235 * while (va < end_va) { 236 * pte = htable_walk(hat, &ht, &va, end_va); 237 * if (!pte) 238 * break; 239 * 240 * ... code to operate on page at va ... 241 * 242 * va += LEVEL_SIZE(ht->ht_level); 243 * } 244 * if (ht) 245 * htable_release(ht); 246 * 247 */ 248 extern x86pte_t htable_walk(struct hat *hat, htable_t **ht, uintptr_t *va, 249 uintptr_t eaddr); 250 251 #define HTABLE_WALK_TO_END ((uintptr_t)-1) 252 253 /* 254 * Utilities convert between virtual addresses and page table entry indeces. 255 */ 256 extern uint_t htable_va2entry(uintptr_t va, htable_t *ht); 257 extern uintptr_t htable_e2va(htable_t *ht, uint_t entry); 258 259 /* 260 * Interfaces that provide access to page table entries via the htable. 261 * 262 * Note that all accesses except x86pte_copy() and x86pte_zero() are atomic. 263 */ 264 extern void x86pte_cpu_init(cpu_t *); 265 extern void x86pte_cpu_fini(cpu_t *); 266 267 extern x86pte_t x86pte_get(htable_t *, uint_t entry); 268 269 /* 270 * x86pte_set returns LPAGE_ERROR if it's asked to overwrite a page table 271 * link with a large page mapping. 272 */ 273 #define LPAGE_ERROR (-(x86pte_t)1) 274 extern x86pte_t x86pte_set(htable_t *, uint_t entry, x86pte_t new, void *); 275 276 extern x86pte_t x86pte_inval(htable_t *ht, uint_t entry, 277 x86pte_t old, x86pte_t *ptr, boolean_t tlb); 278 279 extern x86pte_t x86pte_update(htable_t *ht, uint_t entry, 280 x86pte_t old, x86pte_t new); 281 282 extern void x86pte_copy(htable_t *src, htable_t *dest, uint_t entry, 283 uint_t cnt); 284 285 /* 286 * access to a pagetable knowing only the pfn 287 */ 288 extern x86pte_t *x86pte_mapin(pfn_t, uint_t, htable_t *); 289 extern void x86pte_mapout(void); 290 291 /* 292 * these are actually inlines for "lock; incw", "lock; decw", etc. instructions. 293 */ 294 #define HTABLE_INC(x) atomic_inc16((uint16_t *)&x) 295 #define HTABLE_DEC(x) atomic_dec16((uint16_t *)&x) 296 #define HTABLE_LOCK_INC(ht) atomic_inc_32(&(ht)->ht_lock_cnt) 297 #define HTABLE_LOCK_DEC(ht) atomic_dec_32(&(ht)->ht_lock_cnt) 298 299 #ifdef __xpv 300 extern void xen_flush_va(caddr_t va); 301 extern void xen_gflush_va(caddr_t va, cpuset_t); 302 extern void xen_flush_tlb(void); 303 extern void xen_gflush_tlb(cpuset_t); 304 extern void xen_pin(pfn_t, level_t); 305 extern void xen_unpin(pfn_t); 306 extern int xen_kpm_page(pfn_t, uint_t); 307 308 /* 309 * The hypervisor maps all page tables into our address space read-only. 310 * Under normal circumstances, the hypervisor then handles all updates to 311 * the page tables underneath the covers for us. However, when we are 312 * trying to dump core after a hypervisor panic, the hypervisor is no 313 * longer available to do these updates. To work around the protection 314 * problem, we simply disable write-protect checking for the duration of a 315 * pagetable update operation. 316 */ 317 #define XPV_ALLOW_PAGETABLE_UPDATES() \ 318 { \ 319 if (IN_XPV_PANIC()) \ 320 setcr0((getcr0() & ~CR0_WP) & 0xffffffff); \ 321 } 322 #define XPV_DISALLOW_PAGETABLE_UPDATES() \ 323 { \ 324 if (IN_XPV_PANIC() > 0) \ 325 setcr0((getcr0() | CR0_WP) & 0xffffffff); \ 326 } 327 328 #else /* __xpv */ 329 330 #define XPV_ALLOW_PAGETABLE_UPDATES() 331 #define XPV_DISALLOW_PAGETABLE_UPDATES() 332 333 #endif 334 335 #endif /* _KERNEL */ 336 337 338 #ifdef __cplusplus 339 } 340 #endif 341 342 #endif /* _VM_HTABLE_H */ 343