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 void segkpm_badop(void);
107 static int segkpm_notsup(void);
108 static int segkpm_capable(struct seg *, segcapability_t);
109
110 #define SEGKPM_BADOP(t) (t(*)())segkpm_badop
111 #define SEGKPM_NOTSUP (int(*)())segkpm_notsup
112
113 static struct seg_ops segkpm_ops = {
114 SEGKPM_BADOP(int), /* dup */
115 SEGKPM_BADOP(int), /* unmap */
116 SEGKPM_BADOP(void), /* free */
117 segkpm_fault,
118 SEGKPM_BADOP(int), /* faulta */
119 SEGKPM_BADOP(int), /* setprot */
120 SEGKPM_BADOP(int), /* checkprot */
121 SEGKPM_BADOP(int), /* kluster */
122 SEGKPM_BADOP(size_t), /* swapout */
123 SEGKPM_BADOP(int), /* sync */
124 SEGKPM_BADOP(size_t), /* incore */
125 SEGKPM_BADOP(int), /* lockop */
126 SEGKPM_BADOP(int), /* getprot */
127 SEGKPM_BADOP(u_offset_t), /* getoffset */
128 SEGKPM_BADOP(int), /* gettype */
129 SEGKPM_BADOP(int), /* getvp */
130 SEGKPM_BADOP(int), /* advise */
131 segkpm_dump, /* dump */
132 SEGKPM_NOTSUP, /* pagelock */
133 SEGKPM_BADOP(int), /* setpgsz */
134 SEGKPM_BADOP(int), /* getmemid */
135 SEGKPM_BADOP(lgrp_mem_policy_info_t *), /* getpolicy */
136 segkpm_capable, /* capable */
137 seg_inherit_notsup /* inherit */
138 };
139
140 /*
141 * kpm_pgsz and kpm_pgshft are set by platform layer.
142 */
143 size_t kpm_pgsz; /* kpm page size */
144 uint_t kpm_pgshft; /* kpm page shift */
145 u_offset_t kpm_pgoff; /* kpm page offset mask */
146 uint_t kpmp2pshft; /* kpm page to page shift */
147 pgcnt_t kpmpnpgs; /* how many pages per kpm page */
148
149
150 #ifdef SEGKPM_SUPPORT
151
152 int
segkpm_create(struct seg * seg,void * argsp)153 segkpm_create(struct seg *seg, void *argsp)
154 {
155 struct segkpm_data *skd;
156 struct segkpm_crargs *b = (struct segkpm_crargs *)argsp;
157 ushort_t *p;
158 int i, j;
159
160 ASSERT(seg->s_as && RW_WRITE_HELD(&seg->s_as->a_lock));
161 ASSERT(btokpmp(seg->s_size) >= 1 &&
162 kpmpageoff((uintptr_t)seg->s_base) == 0 &&
163 kpmpageoff((uintptr_t)seg->s_base + seg->s_size) == 0);
164
165 skd = kmem_zalloc(sizeof (struct segkpm_data), KM_SLEEP);
166
167 seg->s_data = (void *)skd;
168 seg->s_ops = &segkpm_ops;
169 skd->skd_prot = b->prot;
170
171 /*
172 * (1) Segkpm virtual addresses are based on physical adresses.
173 * From this and in opposite to other segment drivers it is
174 * often required to allocate a page first to be able to
175 * calculate the final segkpm virtual address.
176 * (2) Page allocation is done by calling page_create_va(),
177 * one important input argument is a virtual address (also
178 * expressed by the "va" in the function name). This function
179 * is highly optimized to select the right page for an optimal
180 * processor and platform support (e.g. virtual addressed
181 * caches (VAC), physical addressed caches, NUMA).
182 *
183 * Because of (1) the approach is to generate a faked virtual
184 * address for calling page_create_va(). In order to exploit
185 * the abilities of (2), especially to utilize the cache
186 * hierarchy (3) and to avoid VAC alias conflicts (4) the
187 * selection has to be done carefully. For each virtual color
188 * a separate counter is provided (4). The count values are
189 * used for the utilization of all cache lines (3) and are
190 * corresponding to the cache bins.
191 */
192 skd->skd_nvcolors = b->nvcolors;
193
194 p = skd->skd_va_select =
195 kmem_zalloc(NCPU * b->nvcolors * sizeof (ushort_t), KM_SLEEP);
196
197 for (i = 0; i < NCPU; i++)
198 for (j = 0; j < b->nvcolors; j++, p++)
199 *p = j;
200
201 return (0);
202 }
203
204 /*
205 * This routine is called via a machine specific fault handling
206 * routine.
207 */
208 /* ARGSUSED */
209 faultcode_t
segkpm_fault(struct hat * hat,struct seg * seg,caddr_t addr,size_t len,enum fault_type type,enum seg_rw rw)210 segkpm_fault(struct hat *hat, struct seg *seg, caddr_t addr, size_t len,
211 enum fault_type type, enum seg_rw rw)
212 {
213 ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as));
214
215 switch (type) {
216 case F_INVAL:
217 return (hat_kpm_fault(hat, addr));
218 case F_SOFTLOCK:
219 case F_SOFTUNLOCK:
220 return (0);
221 default:
222 return (FC_NOSUPPORT);
223 }
224 /*NOTREACHED*/
225 }
226
227 #define addr_to_vcolor(addr, vcolors) \
228 ((int)(((uintptr_t)(addr) & ((vcolors << PAGESHIFT) - 1)) >> PAGESHIFT))
229
230 /*
231 * Create a virtual address that can be used for invocations of
232 * page_create_va. Goal is to utilize the cache hierarchy (round
233 * robin bins) and to select the right color for virtual indexed
234 * caches. It isn't exact since we also increment the bin counter
235 * when the caller uses VOP_GETPAGE and gets a hit in the page
236 * cache, but we keep the bins turning for cache distribution
237 * (see also segkpm_create block comment).
238 */
239 caddr_t
segkpm_create_va(u_offset_t off)240 segkpm_create_va(u_offset_t off)
241 {
242 int vcolor;
243 ushort_t *p;
244 struct segkpm_data *skd = (struct segkpm_data *)segkpm->s_data;
245 int nvcolors = skd->skd_nvcolors;
246 caddr_t va;
247
248 vcolor = (nvcolors > 1) ? addr_to_vcolor(off, nvcolors) : 0;
249 p = &skd->skd_va_select[(CPU->cpu_id * nvcolors) + vcolor];
250 va = (caddr_t)ptob(*p);
251
252 atomic_add_16(p, nvcolors);
253
254 return (va);
255 }
256
257 /*
258 * Unload mapping if the instance has an active kpm mapping.
259 */
260 void
segkpm_mapout_validkpme(struct kpme * kpme)261 segkpm_mapout_validkpme(struct kpme *kpme)
262 {
263 caddr_t vaddr;
264 page_t *pp;
265
266 retry:
267 if ((pp = kpme->kpe_page) == NULL) {
268 return;
269 }
270
271 if (page_lock(pp, SE_SHARED, (kmutex_t *)NULL, P_RECLAIM) == 0)
272 goto retry;
273
274 /*
275 * Check if segkpm mapping is not unloaded in the meantime
276 */
277 if (kpme->kpe_page == NULL) {
278 page_unlock(pp);
279 return;
280 }
281
282 vaddr = hat_kpm_page2va(pp, 1);
283 hat_kpm_mapout(pp, kpme, vaddr);
284 page_unlock(pp);
285 }
286
287 static void
segkpm_badop()288 segkpm_badop()
289 {
290 panic("segkpm_badop");
291 }
292
293 #else /* SEGKPM_SUPPORT */
294
295 /* segkpm stubs */
296
297 /*ARGSUSED*/
segkpm_create(struct seg * seg,void * argsp)298 int segkpm_create(struct seg *seg, void *argsp) { return (0); }
299
300 /* ARGSUSED */
301 faultcode_t
segkpm_fault(struct hat * hat,struct seg * seg,caddr_t addr,size_t len,enum fault_type type,enum seg_rw rw)302 segkpm_fault(struct hat *hat, struct seg *seg, caddr_t addr, size_t len,
303 enum fault_type type, enum seg_rw rw)
304 {
305 return ((faultcode_t)0);
306 }
307
308 /* ARGSUSED */
segkpm_create_va(u_offset_t off)309 caddr_t segkpm_create_va(u_offset_t off) { return (NULL); }
310
311 /* ARGSUSED */
segkpm_mapout_validkpme(struct kpme * kpme)312 void segkpm_mapout_validkpme(struct kpme *kpme) {}
313
314 static void
segkpm_badop()315 segkpm_badop() {}
316
317 #endif /* SEGKPM_SUPPORT */
318
319 static int
segkpm_notsup()320 segkpm_notsup()
321 {
322 return (ENOTSUP);
323 }
324
325 /*
326 * segkpm pages are not dumped, so we just return
327 */
328 /*ARGSUSED*/
329 static void
segkpm_dump(struct seg * seg)330 segkpm_dump(struct seg *seg)
331 {}
332
333 /*
334 * We claim to have no special capabilities.
335 */
336 /*ARGSUSED*/
337 static int
segkpm_capable(struct seg * seg,segcapability_t capability)338 segkpm_capable(struct seg *seg, segcapability_t capability)
339 {
340 return (0);
341 }
342