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, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22 /*
23 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 /*
28 * Kernel Physical Mapping (kpm) segment driver (segkpm).
29 *
30 * This driver delivers along with the hat_kpm* interfaces an alternative
31 * mechanism for kernel mappings within the 64-bit Solaris operating system,
32 * which allows the mapping of all physical memory into the kernel address
33 * space at once. This is feasible in 64 bit kernels, e.g. for Ultrasparc II
34 * and beyond processors, since the available VA range is much larger than
35 * possible physical memory. Momentarily all physical memory is supported,
36 * that is represented by the list of memory segments (memsegs).
37 *
38 * Segkpm mappings have also very low overhead and large pages are used
39 * (when possible) to minimize the TLB and TSB footprint. It is also
40 * extentable for other than Sparc architectures (e.g. AMD64). Main
41 * advantage is the avoidance of the TLB-shootdown X-calls, which are
42 * normally needed when a kernel (global) mapping has to be removed.
43 *
44 * First example of a kernel facility that uses the segkpm mapping scheme
45 * is seg_map, where it is used as an alternative to hat_memload().
46 * See also hat layer for more information about the hat_kpm* routines.
47 * The kpm facilty can be turned off at boot time (e.g. /etc/system).
48 */
49
50 #include <sys/types.h>
51 #include <sys/param.h>
52 #include <sys/sysmacros.h>
53 #include <sys/systm.h>
54 #include <sys/vnode.h>
55 #include <sys/cmn_err.h>
56 #include <sys/debug.h>
57 #include <sys/thread.h>
58 #include <sys/cpuvar.h>
59 #include <sys/bitmap.h>
60 #include <sys/atomic.h>
61 #include <sys/lgrp.h>
62
63 #include <vm/seg_kmem.h>
64 #include <vm/seg_kpm.h>
65 #include <vm/hat.h>
66 #include <vm/as.h>
67 #include <vm/seg.h>
68 #include <vm/page.h>
69
70 /*
71 * Global kpm controls.
72 * See also platform and mmu specific controls.
73 *
74 * kpm_enable -- global on/off switch for segkpm.
75 * . Set by default on 64bit platforms that have kpm support.
76 * . Will be disabled from platform layer if not supported.
77 * . Can be disabled via /etc/system.
78 *
79 * kpm_smallpages -- use only regular/system pagesize for kpm mappings.
80 * . Can be useful for critical debugging of kpm clients.
81 * . Set to zero by default for platforms that support kpm large pages.
82 * The use of kpm large pages reduces the footprint of kpm meta data
83 * and has all the other advantages of using large pages (e.g TLB
84 * miss reduction).
85 * . Set by default for platforms that don't support kpm large pages or
86 * where large pages cannot be used for other reasons (e.g. there are
87 * only few full associative TLB entries available for large pages).
88 *
89 * segmap_kpm -- separate on/off switch for segmap using segkpm:
90 * . Set by default.
91 * . Will be disabled when kpm_enable is zero.
92 * . Will be disabled when MAXBSIZE != PAGESIZE.
93 * . Can be disabled via /etc/system.
94 *
95 */
96 int kpm_enable = 1;
97 int kpm_smallpages = 0;
98 int segmap_kpm = 1;
99
100 /*
101 * Private seg op routines.
102 */
103 faultcode_t segkpm_fault(struct hat *hat, struct seg *seg, caddr_t addr,
104 size_t len, enum fault_type type, enum seg_rw rw);
105 static void segkpm_dump(struct seg *);
106 static int segkpm_pagelock(struct seg *seg, caddr_t addr, size_t len,
107 struct page ***page, enum lock_type type,
108 enum seg_rw rw);
109 static int segkpm_capable(struct seg *, segcapability_t);
110
111 static struct seg_ops segkpm_ops = {
112 .fault = segkpm_fault,
113 .dump = segkpm_dump,
114 .pagelock = segkpm_pagelock,
115 .capable = segkpm_capable,
116 .inherit = seg_inherit_notsup,
117 //#ifndef SEGKPM_SUPPORT
118 #if 0
119 #error FIXME: define nop
120 .dup = nop,
121 .unmap = nop,
122 .free = nop,
123 .faulta = nop,
124 .setprot = nop,
125 .checkprot = nop,
126 .kluster = nop,
127 .sync = nop,
128 .incore = nop,
129 .lockop = nop,
130 .getprot = nop,
131 .getoffset = nop,
132 .gettype = nop,
133 .getvp = nop,
134 .advise = nop,
135 .setpagesize = nop,
136 .getmemid = nop,
137 .getpolicy = nop,
138 #endif
139 };
140
141 /*
142 * kpm_pgsz and kpm_pgshft are set by platform layer.
143 */
144 size_t kpm_pgsz; /* kpm page size */
145 uint_t kpm_pgshft; /* kpm page shift */
146 u_offset_t kpm_pgoff; /* kpm page offset mask */
147 uint_t kpmp2pshft; /* kpm page to page shift */
148 pgcnt_t kpmpnpgs; /* how many pages per kpm page */
149
150
151 #ifdef SEGKPM_SUPPORT
152
153 int
154 segkpm_create(struct seg *seg, void *argsp)
155 {
156 struct segkpm_data *skd;
157 struct segkpm_crargs *b = (struct segkpm_crargs *)argsp;
158 ushort_t *p;
159 int i, j;
160
161 ASSERT(seg->s_as && RW_WRITE_HELD(&seg->s_as->a_lock));
162 ASSERT(btokpmp(seg->s_size) >= 1 &&
163 kpmpageoff((uintptr_t)seg->s_base) == 0 &&
164 kpmpageoff((uintptr_t)seg->s_base + seg->s_size) == 0);
165
166 skd = kmem_zalloc(sizeof (struct segkpm_data), KM_SLEEP);
167
168 seg->s_data = (void *)skd;
169 seg->s_ops = &segkpm_ops;
170 skd->skd_prot = b->prot;
171
172 /*
173 * (1) Segkpm virtual addresses are based on physical adresses.
174 * From this and in opposite to other segment drivers it is
175 * often required to allocate a page first to be able to
176 * calculate the final segkpm virtual address.
177 * (2) Page allocation is done by calling page_create_va(),
178 * one important input argument is a virtual address (also
179 * expressed by the "va" in the function name). This function
180 * is highly optimized to select the right page for an optimal
181 * processor and platform support (e.g. virtual addressed
182 * caches (VAC), physical addressed caches, NUMA).
183 *
184 * Because of (1) the approach is to generate a faked virtual
185 * address for calling page_create_va(). In order to exploit
186 * the abilities of (2), especially to utilize the cache
187 * hierarchy (3) and to avoid VAC alias conflicts (4) the
188 * selection has to be done carefully. For each virtual color
189 * a separate counter is provided (4). The count values are
190 * used for the utilization of all cache lines (3) and are
191 * corresponding to the cache bins.
192 */
193 skd->skd_nvcolors = b->nvcolors;
194
195 p = skd->skd_va_select =
196 kmem_zalloc(NCPU * b->nvcolors * sizeof (ushort_t), KM_SLEEP);
197
198 for (i = 0; i < NCPU; i++)
199 for (j = 0; j < b->nvcolors; j++, p++)
200 *p = j;
201
202 return (0);
203 }
204
205 /*
206 * This routine is called via a machine specific fault handling
207 * routine.
208 */
209 /* ARGSUSED */
210 faultcode_t
211 segkpm_fault(struct hat *hat, struct seg *seg, caddr_t addr, size_t len,
212 enum fault_type type, enum seg_rw rw)
213 {
214 ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
215
216 switch (type) {
217 case F_INVAL:
218 return (hat_kpm_fault(hat, addr));
219 case F_SOFTLOCK:
220 case F_SOFTUNLOCK:
221 return (0);
222 default:
223 return (FC_NOSUPPORT);
224 }
225 /*NOTREACHED*/
226 }
227
228 #define addr_to_vcolor(addr, vcolors) \
229 ((int)(((uintptr_t)(addr) & ((vcolors << PAGESHIFT) - 1)) >> PAGESHIFT))
230
231 /*
232 * Create a virtual address that can be used for invocations of
233 * page_create_va. Goal is to utilize the cache hierarchy (round
234 * robin bins) and to select the right color for virtual indexed
235 * caches. It isn't exact since we also increment the bin counter
236 * when the caller uses VOP_GETPAGE and gets a hit in the page
237 * cache, but we keep the bins turning for cache distribution
238 * (see also segkpm_create block comment).
239 */
240 caddr_t
241 segkpm_create_va(u_offset_t off)
242 {
243 int vcolor;
244 ushort_t *p;
245 struct segkpm_data *skd = (struct segkpm_data *)segkpm->s_data;
246 int nvcolors = skd->skd_nvcolors;
247 caddr_t va;
248
249 vcolor = (nvcolors > 1) ? addr_to_vcolor(off, nvcolors) : 0;
250 p = &skd->skd_va_select[(CPU->cpu_id * nvcolors) + vcolor];
251 va = (caddr_t)ptob(*p);
252
253 atomic_add_16(p, nvcolors);
254
255 return (va);
256 }
257
258 /*
259 * Unload mapping if the instance has an active kpm mapping.
260 */
261 void
262 segkpm_mapout_validkpme(struct kpme *kpme)
263 {
264 caddr_t vaddr;
265 page_t *pp;
266
267 retry:
268 if ((pp = kpme->kpe_page) == NULL) {
269 return;
270 }
271
272 if (page_lock(pp, SE_SHARED, (kmutex_t *)NULL, P_RECLAIM) == 0)
273 goto retry;
274
275 /*
276 * Check if segkpm mapping is not unloaded in the meantime
277 */
278 if (kpme->kpe_page == NULL) {
279 page_unlock(pp);
280 return;
281 }
282
283 vaddr = hat_kpm_page2va(pp, 1);
284 hat_kpm_mapout(pp, kpme, vaddr);
285 page_unlock(pp);
286 }
287
288 #else /* SEGKPM_SUPPORT */
289
290 /* segkpm stubs */
291
292 /*ARGSUSED*/
293 int segkpm_create(struct seg *seg, void *argsp)
294 {
295 return (0);
296 }
297
298 /* ARGSUSED */
299 faultcode_t
300 segkpm_fault(struct hat *hat, struct seg *seg, caddr_t addr, size_t len,
301 enum fault_type type, enum seg_rw rw)
302 {
303 return (0);
304 }
305
306 /* ARGSUSED */
307 caddr_t segkpm_create_va(u_offset_t off)
308 {
309 return (NULL);
310 }
311
312 /* ARGSUSED */
313 void segkpm_mapout_validkpme(struct kpme *kpme)
314 {
315 }
316
317 #endif /* SEGKPM_SUPPORT */
318
319 /* ARGSUSED */
320 static int
321 segkpm_pagelock(struct seg *seg, caddr_t addr, size_t len,
322 struct page ***page, enum lock_type type, enum seg_rw rw)
323 {
324 return (ENOTSUP);
325 }
326
327 /*
328 * segkpm pages are not dumped, so we just return
329 */
330 /*ARGSUSED*/
331 static void
332 segkpm_dump(struct seg *seg)
333 {
334 }
335
336 /*
337 * We claim to have no special capabilities.
338 */
339 /*ARGSUSED*/
340 static int
341 segkpm_capable(struct seg *seg, segcapability_t capability)
342 {
343 return (0);
344 }