xref: /titanic_41/usr/src/uts/i86pc/vm/htable.h (revision 466bf4fee0f1a296eade2107ddeb4c66b825952f)
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