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 * Copyright 2018 Joyent, Inc. 28 */ 29 30 #ifndef _VM_HTABLE_H 31 #define _VM_HTABLE_H 32 33 #ifdef __cplusplus 34 extern "C" { 35 #endif 36 37 #if defined(__GNUC__) && defined(_ASM_INLINES) && defined(_KERNEL) 38 #include <asm/htable.h> 39 #endif 40 41 extern void atomic_andb(uint8_t *addr, uint8_t value); 42 extern void atomic_orb(uint8_t *addr, uint8_t value); 43 extern void atomic_inc16(uint16_t *addr); 44 extern void atomic_dec16(uint16_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_COPIED - This is the top level htable of a HAT being used with per-CPU 89 * pagetables. 90 * 91 * HTABLE_SHARED_PFN - this htable had its PFN assigned from sharing another 92 * htable. Used by hat_share() for ISM. 93 */ 94 #define HTABLE_COPIED (0x01) 95 #define HTABLE_SHARED_PFN (0x02) 96 97 /* 98 * The htable hash table hashing function. The 28 is so that high 99 * order bits are include in the hash index to skew the wrap 100 * around of addresses. Even though the hash buckets are stored per 101 * hat we include the value of hat pointer in the hash function so 102 * that the secondary hash for the htable mutex winds up begin different in 103 * every address space. 104 */ 105 #define HTABLE_HASH(hat, va, lvl) \ 106 ((((va) >> LEVEL_SHIFT(1)) + ((va) >> 28) + (lvl) + \ 107 ((uintptr_t)(hat) >> 4)) & ((hat)->hat_num_hash - 1)) 108 109 /* 110 * Each CPU gets a unique hat_cpu_info structure in cpu_hat_info. For more 111 * information on its use and members, see uts/i86pc/vm/hat_i86.c. 112 */ 113 struct hat_cpu_info { 114 kmutex_t hci_mutex; /* mutex to ensure sequential usage */ 115 #if defined(__amd64) 116 pfn_t hci_pcp_l3pfn; /* pfn of hci_pcp_l3ptes */ 117 pfn_t hci_pcp_l2pfn; /* pfn of hci_pcp_l2ptes */ 118 x86pte_t *hci_pcp_l3ptes; /* PCP Level==3 pagetable (top) */ 119 x86pte_t *hci_pcp_l2ptes; /* PCP Level==2 pagetable */ 120 struct hat *hci_user_hat; /* CPU specific HAT */ 121 pfn_t hci_user_l3pfn; /* pfn of hci_user_l3ptes */ 122 x86pte_t *hci_user_l3ptes; /* PCP User L3 pagetable */ 123 #endif /* __amd64 */ 124 }; 125 126 127 /* 128 * Compute the last page aligned VA mapped by an htable. 129 * 130 * Given a va and a level, compute the virtual address of the start of the 131 * next page at that level. 132 * 133 * XX64 - The check for the VA hole needs to be better generalized. 134 */ 135 #if defined(__amd64) 136 #define HTABLE_NUM_PTES(ht) (((ht)->ht_flags & HTABLE_COPIED) ? \ 137 (((ht)->ht_level == mmu.max_level) ? 512 : 4) : 512) 138 139 #define HTABLE_LAST_PAGE(ht) \ 140 ((ht)->ht_level == mmu.max_level ? ((uintptr_t)0UL - MMU_PAGESIZE) :\ 141 ((ht)->ht_vaddr - MMU_PAGESIZE + \ 142 ((uintptr_t)HTABLE_NUM_PTES(ht) << LEVEL_SHIFT((ht)->ht_level)))) 143 144 #define NEXT_ENTRY_VA(va, l) \ 145 ((va & LEVEL_MASK(l)) + LEVEL_SIZE(l) == mmu.hole_start ? \ 146 mmu.hole_end : (va & LEVEL_MASK(l)) + LEVEL_SIZE(l)) 147 148 #elif defined(__i386) 149 150 #define HTABLE_NUM_PTES(ht) \ 151 (!mmu.pae_hat ? 1024 : ((ht)->ht_level == 2 ? 4 : 512)) 152 153 #define HTABLE_LAST_PAGE(ht) ((ht)->ht_vaddr - MMU_PAGESIZE + \ 154 ((uintptr_t)HTABLE_NUM_PTES(ht) << LEVEL_SHIFT((ht)->ht_level))) 155 156 #define NEXT_ENTRY_VA(va, l) ((va & LEVEL_MASK(l)) + LEVEL_SIZE(l)) 157 158 #endif 159 160 #if defined(_KERNEL) 161 162 /* 163 * initialization function called from hat_init() 164 */ 165 extern void htable_init(void); 166 167 /* 168 * Functions to lookup, or "lookup and create", the htable corresponding 169 * to the virtual address "vaddr" in the "hat" at the given "level" of 170 * page tables. htable_lookup() may return NULL if no such entry exists. 171 * 172 * On return the given htable is marked busy (a shared lock) - this prevents 173 * the htable from being stolen or freed) until htable_release() is called. 174 * 175 * If kalloc_flag is set on an htable_create() we can't call kmem allocation 176 * routines for this htable, since it's for the kernel hat itself. 177 * 178 * htable_acquire() is used when an htable pointer has been extracted from 179 * an hment and we need to get a reference to the htable. 180 */ 181 extern htable_t *htable_lookup(struct hat *hat, uintptr_t vaddr, level_t level); 182 extern htable_t *htable_create(struct hat *hat, uintptr_t vaddr, level_t level, 183 htable_t *shared); 184 extern void htable_acquire(htable_t *); 185 186 extern void htable_release(htable_t *ht); 187 extern void htable_destroy(htable_t *ht); 188 189 /* 190 * Code to free all remaining htables for a hat. Called after the hat is no 191 * longer in use by any thread. 192 */ 193 extern void htable_purge_hat(struct hat *hat); 194 195 /* 196 * Find the htable, page table entry index, and PTE of the given virtual 197 * address. If not found returns NULL. When found, returns the htable_t *, 198 * sets entry, and has a hold on the htable. 199 */ 200 extern htable_t *htable_getpte(struct hat *, uintptr_t, uint_t *, x86pte_t *, 201 level_t); 202 203 /* 204 * Similar to hat_getpte(), except that this only succeeds if a valid 205 * page mapping is present. 206 */ 207 extern htable_t *htable_getpage(struct hat *hat, uintptr_t va, uint_t *entry); 208 209 /* 210 * Called to allocate initial/additional htables for reserve. 211 */ 212 extern void htable_initial_reserve(uint_t); 213 extern void htable_reserve(uint_t); 214 215 /* 216 * Used to readjust the htable reserve after the reserve list has been used. 217 * Also called after boot to release left over boot reserves. 218 */ 219 extern void htable_adjust_reserve(void); 220 221 /* 222 * return number of bytes mapped by all the htables in a given hat 223 */ 224 extern size_t htable_mapped(struct hat *); 225 226 227 /* 228 * Attach initial pagetables as htables 229 */ 230 extern void htable_attach(struct hat *, uintptr_t, level_t, struct htable *, 231 pfn_t); 232 233 /* 234 * Routine to find the next populated htable at or above a given virtual 235 * address. Can specify an upper limit, or HTABLE_WALK_TO_END to indicate 236 * that it should search the entire address space. Similar to 237 * hat_getpte(), but used for walking through address ranges. It can be 238 * used like this: 239 * 240 * va = ... 241 * ht = NULL; 242 * while (va < end_va) { 243 * pte = htable_walk(hat, &ht, &va, end_va); 244 * if (!pte) 245 * break; 246 * 247 * ... code to operate on page at va ... 248 * 249 * va += LEVEL_SIZE(ht->ht_level); 250 * } 251 * if (ht) 252 * htable_release(ht); 253 * 254 */ 255 extern x86pte_t htable_walk(struct hat *hat, htable_t **ht, uintptr_t *va, 256 uintptr_t eaddr); 257 258 #define HTABLE_WALK_TO_END ((uintptr_t)-1) 259 260 /* 261 * Utilities convert between virtual addresses and page table entry indeces. 262 */ 263 extern uint_t htable_va2entry(uintptr_t va, htable_t *ht); 264 extern uintptr_t htable_e2va(htable_t *ht, uint_t entry); 265 266 /* 267 * Interfaces that provide access to page table entries via the htable. 268 * 269 * Note that all accesses except x86pte_copy() and x86pte_zero() are atomic. 270 */ 271 extern void x86pte_cpu_init(cpu_t *); 272 extern void x86pte_cpu_fini(cpu_t *); 273 274 extern x86pte_t x86pte_get(htable_t *, uint_t entry); 275 276 /* 277 * x86pte_set returns LPAGE_ERROR if it's asked to overwrite a page table 278 * link with a large page mapping. 279 */ 280 #define LPAGE_ERROR (-(x86pte_t)1) 281 extern x86pte_t x86pte_set(htable_t *, uint_t entry, x86pte_t new, void *); 282 283 extern x86pte_t x86pte_inval(htable_t *ht, uint_t entry, 284 x86pte_t old, x86pte_t *ptr, boolean_t tlb); 285 286 extern x86pte_t x86pte_update(htable_t *ht, uint_t entry, 287 x86pte_t old, x86pte_t new); 288 289 extern void x86pte_copy(htable_t *src, htable_t *dest, uint_t entry, 290 uint_t cnt); 291 292 /* 293 * access to a pagetable knowing only the pfn 294 */ 295 extern x86pte_t *x86pte_mapin(pfn_t, uint_t, htable_t *); 296 extern void x86pte_mapout(void); 297 298 /* 299 * these are actually inlines for "lock; incw", "lock; decw", etc. instructions. 300 */ 301 #define HTABLE_INC(x) atomic_inc16((uint16_t *)&x) 302 #define HTABLE_DEC(x) atomic_dec16((uint16_t *)&x) 303 #define HTABLE_LOCK_INC(ht) atomic_inc_32(&(ht)->ht_lock_cnt) 304 #define HTABLE_LOCK_DEC(ht) atomic_dec_32(&(ht)->ht_lock_cnt) 305 306 #ifdef __xpv 307 extern void xen_flush_va(caddr_t va); 308 extern void xen_gflush_va(caddr_t va, cpuset_t); 309 extern void xen_flush_tlb(void); 310 extern void xen_gflush_tlb(cpuset_t); 311 extern void xen_pin(pfn_t, level_t); 312 extern void xen_unpin(pfn_t); 313 extern int xen_kpm_page(pfn_t, uint_t); 314 315 /* 316 * The hypervisor maps all page tables into our address space read-only. 317 * Under normal circumstances, the hypervisor then handles all updates to 318 * the page tables underneath the covers for us. However, when we are 319 * trying to dump core after a hypervisor panic, the hypervisor is no 320 * longer available to do these updates. To work around the protection 321 * problem, we simply disable write-protect checking for the duration of a 322 * pagetable update operation. 323 */ 324 #define XPV_ALLOW_PAGETABLE_UPDATES() \ 325 { \ 326 if (IN_XPV_PANIC()) \ 327 setcr0((getcr0() & ~CR0_WP) & 0xffffffff); \ 328 } 329 #define XPV_DISALLOW_PAGETABLE_UPDATES() \ 330 { \ 331 if (IN_XPV_PANIC() > 0) \ 332 setcr0((getcr0() | CR0_WP) & 0xffffffff); \ 333 } 334 335 #else /* __xpv */ 336 337 #define XPV_ALLOW_PAGETABLE_UPDATES() 338 #define XPV_DISALLOW_PAGETABLE_UPDATES() 339 340 #endif 341 342 #endif /* _KERNEL */ 343 344 345 #ifdef __cplusplus 346 } 347 #endif 348 349 #endif /* _VM_HTABLE_H */ 350