Commit | Line | Data |
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9a0deecc JS |
1 | /* |
2 | * SN Platform GRU Driver | |
3 | * | |
4 | * DRIVER TABLE MANAGER + GRU CONTEXT LOAD/UNLOAD | |
5 | * | |
8820f27a | 6 | * Copyright (c) 2008 Silicon Graphics, Inc. All Rights Reserved. |
9a0deecc | 7 | * |
8820f27a JS |
8 | * This program is free software; you can redistribute it and/or modify |
9 | * it under the terms of the GNU General Public License as published by | |
10 | * the Free Software Foundation; either version 2 of the License, or | |
11 | * (at your option) any later version. | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | * GNU General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU General Public License | |
19 | * along with this program; if not, write to the Free Software | |
20 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
9a0deecc JS |
21 | */ |
22 | ||
23 | #include <linux/kernel.h> | |
24 | #include <linux/slab.h> | |
25 | #include <linux/mm.h> | |
26 | #include <linux/spinlock.h> | |
27 | #include <linux/sched.h> | |
28 | #include <linux/device.h> | |
29 | #include <linux/list.h> | |
7f2251b1 | 30 | #include <linux/err.h> |
9a0deecc JS |
31 | #include <asm/uv/uv_hub.h> |
32 | #include "gru.h" | |
33 | #include "grutables.h" | |
34 | #include "gruhandles.h" | |
35 | ||
9ca8e40c | 36 | unsigned long gru_options __read_mostly; |
9a0deecc JS |
37 | |
38 | static struct device_driver gru_driver = { | |
39 | .name = "gru" | |
40 | }; | |
41 | ||
42 | static struct device gru_device = { | |
bb0dc43e | 43 | .init_name = "", |
9a0deecc JS |
44 | .driver = &gru_driver, |
45 | }; | |
46 | ||
47 | struct device *grudev = &gru_device; | |
48 | ||
49 | /* | |
50 | * Select a gru fault map to be used by the current cpu. Note that | |
51 | * multiple cpus may be using the same map. | |
9a0deecc JS |
52 | * ZZZ should be inline but did not work on emulator |
53 | */ | |
54 | int gru_cpu_fault_map_id(void) | |
55 | { | |
41314790 JS |
56 | #ifdef CONFIG_IA64 |
57 | return uv_blade_processor_id() % GRU_NUM_TFM; | |
58 | #else | |
4107e1d3 JS |
59 | int cpu = smp_processor_id(); |
60 | int id, core; | |
61 | ||
62 | core = uv_cpu_core_number(cpu); | |
63 | id = core + UV_MAX_INT_CORES * uv_cpu_socket_number(cpu); | |
64 | return id; | |
41314790 | 65 | #endif |
9a0deecc JS |
66 | } |
67 | ||
68 | /*--------- ASID Management ------------------------------------------- | |
69 | * | |
70 | * Initially, assign asids sequentially from MIN_ASID .. MAX_ASID. | |
71 | * Once MAX is reached, flush the TLB & start over. However, | |
72 | * some asids may still be in use. There won't be many (percentage wise) still | |
73 | * in use. Search active contexts & determine the value of the first | |
74 | * asid in use ("x"s below). Set "limit" to this value. | |
75 | * This defines a block of assignable asids. | |
76 | * | |
77 | * When "limit" is reached, search forward from limit+1 and determine the | |
78 | * next block of assignable asids. | |
79 | * | |
80 | * Repeat until MAX_ASID is reached, then start over again. | |
81 | * | |
82 | * Each time MAX_ASID is reached, increment the asid generation. Since | |
83 | * the search for in-use asids only checks contexts with GRUs currently | |
84 | * assigned, asids in some contexts will be missed. Prior to loading | |
85 | * a context, the asid generation of the GTS asid is rechecked. If it | |
86 | * doesn't match the current generation, a new asid will be assigned. | |
87 | * | |
88 | * 0---------------x------------x---------------------x----| | |
89 | * ^-next ^-limit ^-MAX_ASID | |
90 | * | |
91 | * All asid manipulation & context loading/unloading is protected by the | |
92 | * gs_lock. | |
93 | */ | |
94 | ||
95 | /* Hit the asid limit. Start over */ | |
96 | static int gru_wrap_asid(struct gru_state *gru) | |
97 | { | |
43884604 | 98 | gru_dbg(grudev, "gid %d\n", gru->gs_gid); |
9a0deecc JS |
99 | STAT(asid_wrap); |
100 | gru->gs_asid_gen++; | |
9a0deecc JS |
101 | return MIN_ASID; |
102 | } | |
103 | ||
104 | /* Find the next chunk of unused asids */ | |
105 | static int gru_reset_asid_limit(struct gru_state *gru, int asid) | |
106 | { | |
107 | int i, gid, inuse_asid, limit; | |
108 | ||
43884604 | 109 | gru_dbg(grudev, "gid %d, asid 0x%x\n", gru->gs_gid, asid); |
9a0deecc JS |
110 | STAT(asid_next); |
111 | limit = MAX_ASID; | |
112 | if (asid >= limit) | |
113 | asid = gru_wrap_asid(gru); | |
87419412 | 114 | gru_flush_all_tlb(gru); |
9a0deecc JS |
115 | gid = gru->gs_gid; |
116 | again: | |
117 | for (i = 0; i < GRU_NUM_CCH; i++) { | |
836ce679 | 118 | if (!gru->gs_gts[i] || is_kernel_context(gru->gs_gts[i])) |
9a0deecc JS |
119 | continue; |
120 | inuse_asid = gru->gs_gts[i]->ts_gms->ms_asids[gid].mt_asid; | |
43884604 JS |
121 | gru_dbg(grudev, "gid %d, gts %p, gms %p, inuse 0x%x, cxt %d\n", |
122 | gru->gs_gid, gru->gs_gts[i], gru->gs_gts[i]->ts_gms, | |
123 | inuse_asid, i); | |
9a0deecc JS |
124 | if (inuse_asid == asid) { |
125 | asid += ASID_INC; | |
126 | if (asid >= limit) { | |
127 | /* | |
128 | * empty range: reset the range limit and | |
129 | * start over | |
130 | */ | |
131 | limit = MAX_ASID; | |
132 | if (asid >= MAX_ASID) | |
133 | asid = gru_wrap_asid(gru); | |
134 | goto again; | |
135 | } | |
136 | } | |
137 | ||
138 | if ((inuse_asid > asid) && (inuse_asid < limit)) | |
139 | limit = inuse_asid; | |
140 | } | |
141 | gru->gs_asid_limit = limit; | |
142 | gru->gs_asid = asid; | |
43884604 JS |
143 | gru_dbg(grudev, "gid %d, new asid 0x%x, new_limit 0x%x\n", gru->gs_gid, |
144 | asid, limit); | |
9a0deecc JS |
145 | return asid; |
146 | } | |
147 | ||
148 | /* Assign a new ASID to a thread context. */ | |
149 | static int gru_assign_asid(struct gru_state *gru) | |
150 | { | |
151 | int asid; | |
152 | ||
9a0deecc JS |
153 | gru->gs_asid += ASID_INC; |
154 | asid = gru->gs_asid; | |
155 | if (asid >= gru->gs_asid_limit) | |
156 | asid = gru_reset_asid_limit(gru, asid); | |
9a0deecc | 157 | |
43884604 | 158 | gru_dbg(grudev, "gid %d, asid 0x%x\n", gru->gs_gid, asid); |
9a0deecc JS |
159 | return asid; |
160 | } | |
161 | ||
162 | /* | |
163 | * Clear n bits in a word. Return a word indicating the bits that were cleared. | |
164 | * Optionally, build an array of chars that contain the bit numbers allocated. | |
165 | */ | |
166 | static unsigned long reserve_resources(unsigned long *p, int n, int mmax, | |
167 | char *idx) | |
168 | { | |
169 | unsigned long bits = 0; | |
170 | int i; | |
171 | ||
3eac2e95 | 172 | while (n--) { |
9a0deecc JS |
173 | i = find_first_bit(p, mmax); |
174 | if (i == mmax) | |
175 | BUG(); | |
176 | __clear_bit(i, p); | |
177 | __set_bit(i, &bits); | |
178 | if (idx) | |
179 | *idx++ = i; | |
3eac2e95 | 180 | } |
9a0deecc JS |
181 | return bits; |
182 | } | |
183 | ||
9ca8e40c | 184 | unsigned long gru_reserve_cb_resources(struct gru_state *gru, int cbr_au_count, |
9a0deecc JS |
185 | char *cbmap) |
186 | { | |
187 | return reserve_resources(&gru->gs_cbr_map, cbr_au_count, GRU_CBR_AU, | |
188 | cbmap); | |
189 | } | |
190 | ||
9ca8e40c | 191 | unsigned long gru_reserve_ds_resources(struct gru_state *gru, int dsr_au_count, |
9a0deecc JS |
192 | char *dsmap) |
193 | { | |
194 | return reserve_resources(&gru->gs_dsr_map, dsr_au_count, GRU_DSR_AU, | |
195 | dsmap); | |
196 | } | |
197 | ||
198 | static void reserve_gru_resources(struct gru_state *gru, | |
199 | struct gru_thread_state *gts) | |
200 | { | |
201 | gru->gs_active_contexts++; | |
202 | gts->ts_cbr_map = | |
9ca8e40c | 203 | gru_reserve_cb_resources(gru, gts->ts_cbr_au_count, |
9a0deecc JS |
204 | gts->ts_cbr_idx); |
205 | gts->ts_dsr_map = | |
9ca8e40c | 206 | gru_reserve_ds_resources(gru, gts->ts_dsr_au_count, NULL); |
9a0deecc JS |
207 | } |
208 | ||
209 | static void free_gru_resources(struct gru_state *gru, | |
210 | struct gru_thread_state *gts) | |
211 | { | |
212 | gru->gs_active_contexts--; | |
213 | gru->gs_cbr_map |= gts->ts_cbr_map; | |
214 | gru->gs_dsr_map |= gts->ts_dsr_map; | |
215 | } | |
216 | ||
217 | /* | |
218 | * Check if a GRU has sufficient free resources to satisfy an allocation | |
219 | * request. Note: GRU locks may or may not be held when this is called. If | |
220 | * not held, recheck after acquiring the appropriate locks. | |
221 | * | |
222 | * Returns 1 if sufficient resources, 0 if not | |
223 | */ | |
224 | static int check_gru_resources(struct gru_state *gru, int cbr_au_count, | |
225 | int dsr_au_count, int max_active_contexts) | |
226 | { | |
227 | return hweight64(gru->gs_cbr_map) >= cbr_au_count | |
228 | && hweight64(gru->gs_dsr_map) >= dsr_au_count | |
229 | && gru->gs_active_contexts < max_active_contexts; | |
230 | } | |
231 | ||
232 | /* | |
233 | * TLB manangment requires tracking all GRU chiplets that have loaded a GSEG | |
234 | * context. | |
235 | */ | |
43884604 JS |
236 | static int gru_load_mm_tracker(struct gru_state *gru, |
237 | struct gru_thread_state *gts) | |
9a0deecc | 238 | { |
43884604 | 239 | struct gru_mm_struct *gms = gts->ts_gms; |
9a0deecc | 240 | struct gru_mm_tracker *asids = &gms->ms_asids[gru->gs_gid]; |
43884604 | 241 | unsigned short ctxbitmap = (1 << gts->ts_ctxnum); |
9a0deecc JS |
242 | int asid; |
243 | ||
244 | spin_lock(&gms->ms_asid_lock); | |
245 | asid = asids->mt_asid; | |
246 | ||
87419412 JS |
247 | spin_lock(&gru->gs_asid_lock); |
248 | if (asid == 0 || (asids->mt_ctxbitmap == 0 && asids->mt_asid_gen != | |
249 | gru->gs_asid_gen)) { | |
9a0deecc JS |
250 | asid = gru_assign_asid(gru); |
251 | asids->mt_asid = asid; | |
252 | asids->mt_asid_gen = gru->gs_asid_gen; | |
253 | STAT(asid_new); | |
254 | } else { | |
255 | STAT(asid_reuse); | |
256 | } | |
87419412 | 257 | spin_unlock(&gru->gs_asid_lock); |
9a0deecc JS |
258 | |
259 | BUG_ON(asids->mt_ctxbitmap & ctxbitmap); | |
260 | asids->mt_ctxbitmap |= ctxbitmap; | |
261 | if (!test_bit(gru->gs_gid, gms->ms_asidmap)) | |
262 | __set_bit(gru->gs_gid, gms->ms_asidmap); | |
263 | spin_unlock(&gms->ms_asid_lock); | |
264 | ||
265 | gru_dbg(grudev, | |
43884604 JS |
266 | "gid %d, gts %p, gms %p, ctxnum %d, asid 0x%x, asidmap 0x%lx\n", |
267 | gru->gs_gid, gts, gms, gts->ts_ctxnum, asid, | |
268 | gms->ms_asidmap[0]); | |
9a0deecc JS |
269 | return asid; |
270 | } | |
271 | ||
272 | static void gru_unload_mm_tracker(struct gru_state *gru, | |
43884604 | 273 | struct gru_thread_state *gts) |
9a0deecc | 274 | { |
43884604 | 275 | struct gru_mm_struct *gms = gts->ts_gms; |
9a0deecc JS |
276 | struct gru_mm_tracker *asids; |
277 | unsigned short ctxbitmap; | |
278 | ||
279 | asids = &gms->ms_asids[gru->gs_gid]; | |
43884604 | 280 | ctxbitmap = (1 << gts->ts_ctxnum); |
9a0deecc | 281 | spin_lock(&gms->ms_asid_lock); |
87419412 | 282 | spin_lock(&gru->gs_asid_lock); |
9a0deecc JS |
283 | BUG_ON((asids->mt_ctxbitmap & ctxbitmap) != ctxbitmap); |
284 | asids->mt_ctxbitmap ^= ctxbitmap; | |
43884604 JS |
285 | gru_dbg(grudev, "gid %d, gts %p, gms %p, ctxnum 0x%d, asidmap 0x%lx\n", |
286 | gru->gs_gid, gts, gms, gts->ts_ctxnum, gms->ms_asidmap[0]); | |
87419412 | 287 | spin_unlock(&gru->gs_asid_lock); |
9a0deecc JS |
288 | spin_unlock(&gms->ms_asid_lock); |
289 | } | |
290 | ||
291 | /* | |
292 | * Decrement the reference count on a GTS structure. Free the structure | |
293 | * if the reference count goes to zero. | |
294 | */ | |
295 | void gts_drop(struct gru_thread_state *gts) | |
296 | { | |
297 | if (gts && atomic_dec_return(>s->ts_refcnt) == 0) { | |
7f2251b1 JS |
298 | if (gts->ts_gms) |
299 | gru_drop_mmu_notifier(gts->ts_gms); | |
9a0deecc JS |
300 | kfree(gts); |
301 | STAT(gts_free); | |
302 | } | |
303 | } | |
304 | ||
305 | /* | |
306 | * Locate the GTS structure for the current thread. | |
307 | */ | |
308 | static struct gru_thread_state *gru_find_current_gts_nolock(struct gru_vma_data | |
309 | *vdata, int tsid) | |
310 | { | |
311 | struct gru_thread_state *gts; | |
312 | ||
313 | list_for_each_entry(gts, &vdata->vd_head, ts_next) | |
314 | if (gts->ts_tsid == tsid) | |
315 | return gts; | |
316 | return NULL; | |
317 | } | |
318 | ||
319 | /* | |
320 | * Allocate a thread state structure. | |
321 | */ | |
364b76df | 322 | struct gru_thread_state *gru_alloc_gts(struct vm_area_struct *vma, |
c550222f JS |
323 | int cbr_au_count, int dsr_au_count, |
324 | unsigned char tlb_preload_count, int options, int tsid) | |
9a0deecc JS |
325 | { |
326 | struct gru_thread_state *gts; | |
7f2251b1 | 327 | struct gru_mm_struct *gms; |
9a0deecc JS |
328 | int bytes; |
329 | ||
364b76df | 330 | bytes = DSR_BYTES(dsr_au_count) + CBR_BYTES(cbr_au_count); |
9a0deecc | 331 | bytes += sizeof(struct gru_thread_state); |
940229b9 | 332 | gts = kmalloc(bytes, GFP_KERNEL); |
9a0deecc | 333 | if (!gts) |
7f2251b1 | 334 | return ERR_PTR(-ENOMEM); |
9a0deecc JS |
335 | |
336 | STAT(gts_alloc); | |
940229b9 | 337 | memset(gts, 0, sizeof(struct gru_thread_state)); /* zero out header */ |
9a0deecc JS |
338 | atomic_set(>s->ts_refcnt, 1); |
339 | mutex_init(>s->ts_ctxlock); | |
364b76df JS |
340 | gts->ts_cbr_au_count = cbr_au_count; |
341 | gts->ts_dsr_au_count = dsr_au_count; | |
c550222f | 342 | gts->ts_tlb_preload_count = tlb_preload_count; |
364b76df | 343 | gts->ts_user_options = options; |
518e5cd4 JS |
344 | gts->ts_user_blade_id = -1; |
345 | gts->ts_user_chiplet_id = -1; | |
9a0deecc | 346 | gts->ts_tsid = tsid; |
9a0deecc | 347 | gts->ts_ctxnum = NULLCTX; |
9a0deecc | 348 | gts->ts_tlb_int_select = -1; |
b1b19fcf | 349 | gts->ts_cch_req_slice = -1; |
7b8274e9 | 350 | gts->ts_sizeavail = GRU_SIZEAVAIL(PAGE_SHIFT); |
364b76df JS |
351 | if (vma) { |
352 | gts->ts_mm = current->mm; | |
353 | gts->ts_vma = vma; | |
7f2251b1 JS |
354 | gms = gru_register_mmu_notifier(); |
355 | if (IS_ERR(gms)) | |
364b76df | 356 | goto err; |
7f2251b1 | 357 | gts->ts_gms = gms; |
364b76df | 358 | } |
9a0deecc | 359 | |
364b76df | 360 | gru_dbg(grudev, "alloc gts %p\n", gts); |
9a0deecc JS |
361 | return gts; |
362 | ||
363 | err: | |
364 | gts_drop(gts); | |
7f2251b1 | 365 | return ERR_CAST(gms); |
9a0deecc JS |
366 | } |
367 | ||
368 | /* | |
369 | * Allocate a vma private data structure. | |
370 | */ | |
371 | struct gru_vma_data *gru_alloc_vma_data(struct vm_area_struct *vma, int tsid) | |
372 | { | |
373 | struct gru_vma_data *vdata = NULL; | |
374 | ||
375 | vdata = kmalloc(sizeof(*vdata), GFP_KERNEL); | |
376 | if (!vdata) | |
377 | return NULL; | |
378 | ||
563447d7 | 379 | STAT(vdata_alloc); |
9a0deecc JS |
380 | INIT_LIST_HEAD(&vdata->vd_head); |
381 | spin_lock_init(&vdata->vd_lock); | |
382 | gru_dbg(grudev, "alloc vdata %p\n", vdata); | |
383 | return vdata; | |
384 | } | |
385 | ||
386 | /* | |
387 | * Find the thread state structure for the current thread. | |
388 | */ | |
389 | struct gru_thread_state *gru_find_thread_state(struct vm_area_struct *vma, | |
390 | int tsid) | |
391 | { | |
392 | struct gru_vma_data *vdata = vma->vm_private_data; | |
393 | struct gru_thread_state *gts; | |
394 | ||
395 | spin_lock(&vdata->vd_lock); | |
396 | gts = gru_find_current_gts_nolock(vdata, tsid); | |
397 | spin_unlock(&vdata->vd_lock); | |
398 | gru_dbg(grudev, "vma %p, gts %p\n", vma, gts); | |
399 | return gts; | |
400 | } | |
401 | ||
402 | /* | |
403 | * Allocate a new thread state for a GSEG. Note that races may allow | |
404 | * another thread to race to create a gts. | |
405 | */ | |
406 | struct gru_thread_state *gru_alloc_thread_state(struct vm_area_struct *vma, | |
407 | int tsid) | |
408 | { | |
409 | struct gru_vma_data *vdata = vma->vm_private_data; | |
410 | struct gru_thread_state *gts, *ngts; | |
411 | ||
c550222f JS |
412 | gts = gru_alloc_gts(vma, vdata->vd_cbr_au_count, |
413 | vdata->vd_dsr_au_count, | |
414 | vdata->vd_tlb_preload_count, | |
364b76df | 415 | vdata->vd_user_options, tsid); |
7f2251b1 JS |
416 | if (IS_ERR(gts)) |
417 | return gts; | |
9a0deecc JS |
418 | |
419 | spin_lock(&vdata->vd_lock); | |
420 | ngts = gru_find_current_gts_nolock(vdata, tsid); | |
421 | if (ngts) { | |
422 | gts_drop(gts); | |
423 | gts = ngts; | |
424 | STAT(gts_double_allocate); | |
425 | } else { | |
426 | list_add(>s->ts_next, &vdata->vd_head); | |
427 | } | |
428 | spin_unlock(&vdata->vd_lock); | |
429 | gru_dbg(grudev, "vma %p, gts %p\n", vma, gts); | |
430 | return gts; | |
431 | } | |
432 | ||
433 | /* | |
434 | * Free the GRU context assigned to the thread state. | |
435 | */ | |
436 | static void gru_free_gru_context(struct gru_thread_state *gts) | |
437 | { | |
438 | struct gru_state *gru; | |
439 | ||
440 | gru = gts->ts_gru; | |
43884604 | 441 | gru_dbg(grudev, "gts %p, gid %d\n", gts, gru->gs_gid); |
9a0deecc JS |
442 | |
443 | spin_lock(&gru->gs_lock); | |
444 | gru->gs_gts[gts->ts_ctxnum] = NULL; | |
445 | free_gru_resources(gru, gts); | |
446 | BUG_ON(test_bit(gts->ts_ctxnum, &gru->gs_context_map) == 0); | |
447 | __clear_bit(gts->ts_ctxnum, &gru->gs_context_map); | |
448 | gts->ts_ctxnum = NULLCTX; | |
449 | gts->ts_gru = NULL; | |
87419412 | 450 | gts->ts_blade = -1; |
9a0deecc JS |
451 | spin_unlock(&gru->gs_lock); |
452 | ||
453 | gts_drop(gts); | |
454 | STAT(free_context); | |
455 | } | |
456 | ||
457 | /* | |
458 | * Prefetching cachelines help hardware performance. | |
9ca8e40c | 459 | * (Strictly a performance enhancement. Not functionally required). |
9a0deecc JS |
460 | */ |
461 | static void prefetch_data(void *p, int num, int stride) | |
462 | { | |
463 | while (num-- > 0) { | |
464 | prefetchw(p); | |
465 | p += stride; | |
466 | } | |
467 | } | |
468 | ||
469 | static inline long gru_copy_handle(void *d, void *s) | |
470 | { | |
471 | memcpy(d, s, GRU_HANDLE_BYTES); | |
472 | return GRU_HANDLE_BYTES; | |
473 | } | |
474 | ||
fe5bb6b0 JS |
475 | static void gru_prefetch_context(void *gseg, void *cb, void *cbe, |
476 | unsigned long cbrmap, unsigned long length) | |
9a0deecc | 477 | { |
9a0deecc JS |
478 | int i, scr; |
479 | ||
9a0deecc JS |
480 | prefetch_data(gseg + GRU_DS_BASE, length / GRU_CACHE_LINE_BYTES, |
481 | GRU_CACHE_LINE_BYTES); | |
482 | ||
9a0deecc JS |
483 | for_each_cbr_in_allocation_map(i, &cbrmap, scr) { |
484 | prefetch_data(cb, 1, GRU_CACHE_LINE_BYTES); | |
485 | prefetch_data(cbe + i * GRU_HANDLE_STRIDE, 1, | |
486 | GRU_CACHE_LINE_BYTES); | |
487 | cb += GRU_HANDLE_STRIDE; | |
488 | } | |
923f7f69 JS |
489 | } |
490 | ||
491 | static void gru_load_context_data(void *save, void *grubase, int ctxnum, | |
940229b9 JS |
492 | unsigned long cbrmap, unsigned long dsrmap, |
493 | int data_valid) | |
923f7f69 JS |
494 | { |
495 | void *gseg, *cb, *cbe; | |
496 | unsigned long length; | |
497 | int i, scr; | |
9a0deecc | 498 | |
923f7f69 | 499 | gseg = grubase + ctxnum * GRU_GSEG_STRIDE; |
9a0deecc | 500 | cb = gseg + GRU_CB_BASE; |
923f7f69 JS |
501 | cbe = grubase + GRU_CBE_BASE; |
502 | length = hweight64(dsrmap) * GRU_DSR_AU_BYTES; | |
503 | gru_prefetch_context(gseg, cb, cbe, cbrmap, length); | |
504 | ||
9a0deecc | 505 | for_each_cbr_in_allocation_map(i, &cbrmap, scr) { |
940229b9 JS |
506 | if (data_valid) { |
507 | save += gru_copy_handle(cb, save); | |
508 | save += gru_copy_handle(cbe + i * GRU_HANDLE_STRIDE, | |
509 | save); | |
510 | } else { | |
511 | memset(cb, 0, GRU_CACHE_LINE_BYTES); | |
512 | memset(cbe + i * GRU_HANDLE_STRIDE, 0, | |
513 | GRU_CACHE_LINE_BYTES); | |
514 | } | |
67bf04a5 JS |
515 | /* Flush CBE to hide race in context restart */ |
516 | mb(); | |
517 | gru_flush_cache(cbe + i * GRU_HANDLE_STRIDE); | |
9a0deecc JS |
518 | cb += GRU_HANDLE_STRIDE; |
519 | } | |
520 | ||
940229b9 JS |
521 | if (data_valid) |
522 | memcpy(gseg + GRU_DS_BASE, save, length); | |
523 | else | |
524 | memset(gseg + GRU_DS_BASE, 0, length); | |
9a0deecc JS |
525 | } |
526 | ||
527 | static void gru_unload_context_data(void *save, void *grubase, int ctxnum, | |
528 | unsigned long cbrmap, unsigned long dsrmap) | |
529 | { | |
530 | void *gseg, *cb, *cbe; | |
531 | unsigned long length; | |
532 | int i, scr; | |
533 | ||
534 | gseg = grubase + ctxnum * GRU_GSEG_STRIDE; | |
9a0deecc JS |
535 | cb = gseg + GRU_CB_BASE; |
536 | cbe = grubase + GRU_CBE_BASE; | |
923f7f69 | 537 | length = hweight64(dsrmap) * GRU_DSR_AU_BYTES; |
67bf04a5 JS |
538 | |
539 | /* CBEs may not be coherent. Flush them from cache */ | |
540 | for_each_cbr_in_allocation_map(i, &cbrmap, scr) | |
541 | gru_flush_cache(cbe + i * GRU_HANDLE_STRIDE); | |
542 | mb(); /* Let the CL flush complete */ | |
543 | ||
923f7f69 JS |
544 | gru_prefetch_context(gseg, cb, cbe, cbrmap, length); |
545 | ||
9a0deecc JS |
546 | for_each_cbr_in_allocation_map(i, &cbrmap, scr) { |
547 | save += gru_copy_handle(save, cb); | |
548 | save += gru_copy_handle(save, cbe + i * GRU_HANDLE_STRIDE); | |
549 | cb += GRU_HANDLE_STRIDE; | |
550 | } | |
9a0deecc JS |
551 | memcpy(save, gseg + GRU_DS_BASE, length); |
552 | } | |
553 | ||
554 | void gru_unload_context(struct gru_thread_state *gts, int savestate) | |
555 | { | |
556 | struct gru_state *gru = gts->ts_gru; | |
557 | struct gru_context_configuration_handle *cch; | |
558 | int ctxnum = gts->ts_ctxnum; | |
559 | ||
836ce679 JS |
560 | if (!is_kernel_context(gts)) |
561 | zap_vma_ptes(gts->ts_vma, UGRUADDR(gts), GRU_GSEG_PAGESIZE); | |
9a0deecc JS |
562 | cch = get_cch(gru->gs_gru_base_vaddr, ctxnum); |
563 | ||
563447d7 JS |
564 | gru_dbg(grudev, "gts %p, cbrmap 0x%lx, dsrmap 0x%lx\n", |
565 | gts, gts->ts_cbr_map, gts->ts_dsr_map); | |
9a0deecc JS |
566 | lock_cch_handle(cch); |
567 | if (cch_interrupt_sync(cch)) | |
568 | BUG(); | |
9a0deecc | 569 | |
836ce679 JS |
570 | if (!is_kernel_context(gts)) |
571 | gru_unload_mm_tracker(gru, gts); | |
940229b9 | 572 | if (savestate) { |
9a0deecc JS |
573 | gru_unload_context_data(gts->ts_gdata, gru->gs_gru_base_vaddr, |
574 | ctxnum, gts->ts_cbr_map, | |
575 | gts->ts_dsr_map); | |
940229b9 JS |
576 | gts->ts_data_valid = 1; |
577 | } | |
9a0deecc JS |
578 | |
579 | if (cch_deallocate(cch)) | |
580 | BUG(); | |
9a0deecc JS |
581 | unlock_cch_handle(cch); |
582 | ||
583 | gru_free_gru_context(gts); | |
9a0deecc JS |
584 | } |
585 | ||
586 | /* | |
587 | * Load a GRU context by copying it from the thread data structure in memory | |
588 | * to the GRU. | |
589 | */ | |
d57c82b1 | 590 | void gru_load_context(struct gru_thread_state *gts) |
9a0deecc JS |
591 | { |
592 | struct gru_state *gru = gts->ts_gru; | |
593 | struct gru_context_configuration_handle *cch; | |
6e910074 | 594 | int i, err, asid, ctxnum = gts->ts_ctxnum; |
9a0deecc | 595 | |
9a0deecc | 596 | cch = get_cch(gru->gs_gru_base_vaddr, ctxnum); |
9a0deecc | 597 | lock_cch_handle(cch); |
9a0deecc JS |
598 | cch->tfm_fault_bit_enable = |
599 | (gts->ts_user_options == GRU_OPT_MISS_FMM_POLL | |
600 | || gts->ts_user_options == GRU_OPT_MISS_FMM_INTR); | |
601 | cch->tlb_int_enable = (gts->ts_user_options == GRU_OPT_MISS_FMM_INTR); | |
602 | if (cch->tlb_int_enable) { | |
603 | gts->ts_tlb_int_select = gru_cpu_fault_map_id(); | |
604 | cch->tlb_int_select = gts->ts_tlb_int_select; | |
605 | } | |
b1b19fcf JS |
606 | if (gts->ts_cch_req_slice >= 0) { |
607 | cch->req_slice_set_enable = 1; | |
608 | cch->req_slice = gts->ts_cch_req_slice; | |
609 | } else { | |
610 | cch->req_slice_set_enable =0; | |
611 | } | |
9a0deecc | 612 | cch->tfm_done_bit_enable = 0; |
6e910074 JS |
613 | cch->dsr_allocation_map = gts->ts_dsr_map; |
614 | cch->cbr_allocation_map = gts->ts_cbr_map; | |
836ce679 JS |
615 | |
616 | if (is_kernel_context(gts)) { | |
617 | cch->unmap_enable = 1; | |
4a7a17c1 JS |
618 | cch->tfm_done_bit_enable = 1; |
619 | cch->cb_int_enable = 1; | |
4107e1d3 | 620 | cch->tlb_int_select = 0; /* For now, ints go to cpu 0 */ |
836ce679 JS |
621 | } else { |
622 | cch->unmap_enable = 0; | |
4a7a17c1 JS |
623 | cch->tfm_done_bit_enable = 0; |
624 | cch->cb_int_enable = 0; | |
836ce679 JS |
625 | asid = gru_load_mm_tracker(gru, gts); |
626 | for (i = 0; i < 8; i++) { | |
627 | cch->asid[i] = asid + i; | |
628 | cch->sizeavail[i] = gts->ts_sizeavail; | |
629 | } | |
6e910074 JS |
630 | } |
631 | ||
632 | err = cch_allocate(cch); | |
9a0deecc JS |
633 | if (err) { |
634 | gru_dbg(grudev, | |
635 | "err %d: cch %p, gts %p, cbr 0x%lx, dsr 0x%lx\n", | |
636 | err, cch, gts, gts->ts_cbr_map, gts->ts_dsr_map); | |
637 | BUG(); | |
638 | } | |
639 | ||
640 | gru_load_context_data(gts->ts_gdata, gru->gs_gru_base_vaddr, ctxnum, | |
940229b9 | 641 | gts->ts_cbr_map, gts->ts_dsr_map, gts->ts_data_valid); |
9a0deecc JS |
642 | |
643 | if (cch_start(cch)) | |
644 | BUG(); | |
645 | unlock_cch_handle(cch); | |
563447d7 JS |
646 | |
647 | gru_dbg(grudev, "gid %d, gts %p, cbrmap 0x%lx, dsrmap 0x%lx, tie %d, tis %d\n", | |
648 | gts->ts_gru->gs_gid, gts, gts->ts_cbr_map, gts->ts_dsr_map, | |
649 | (gts->ts_user_options == GRU_OPT_MISS_FMM_INTR), gts->ts_tlb_int_select); | |
9a0deecc JS |
650 | } |
651 | ||
652 | /* | |
653 | * Update fields in an active CCH: | |
654 | * - retarget interrupts on local blade | |
7b8274e9 | 655 | * - update sizeavail mask |
9a0deecc | 656 | */ |
99f7c229 | 657 | int gru_update_cch(struct gru_thread_state *gts) |
9a0deecc JS |
658 | { |
659 | struct gru_context_configuration_handle *cch; | |
660 | struct gru_state *gru = gts->ts_gru; | |
661 | int i, ctxnum = gts->ts_ctxnum, ret = 0; | |
662 | ||
663 | cch = get_cch(gru->gs_gru_base_vaddr, ctxnum); | |
664 | ||
665 | lock_cch_handle(cch); | |
666 | if (cch->state == CCHSTATE_ACTIVE) { | |
667 | if (gru->gs_gts[gts->ts_ctxnum] != gts) | |
668 | goto exit; | |
669 | if (cch_interrupt(cch)) | |
670 | BUG(); | |
99f7c229 JS |
671 | for (i = 0; i < 8; i++) |
672 | cch->sizeavail[i] = gts->ts_sizeavail; | |
673 | gts->ts_tlb_int_select = gru_cpu_fault_map_id(); | |
674 | cch->tlb_int_select = gru_cpu_fault_map_id(); | |
675 | cch->tfm_fault_bit_enable = | |
676 | (gts->ts_user_options == GRU_OPT_MISS_FMM_POLL | |
677 | || gts->ts_user_options == GRU_OPT_MISS_FMM_INTR); | |
9a0deecc JS |
678 | if (cch_start(cch)) |
679 | BUG(); | |
680 | ret = 1; | |
681 | } | |
682 | exit: | |
683 | unlock_cch_handle(cch); | |
684 | return ret; | |
685 | } | |
686 | ||
687 | /* | |
688 | * Update CCH tlb interrupt select. Required when all the following is true: | |
689 | * - task's GRU context is loaded into a GRU | |
690 | * - task is using interrupt notification for TLB faults | |
691 | * - task has migrated to a different cpu on the same blade where | |
692 | * it was previously running. | |
693 | */ | |
694 | static int gru_retarget_intr(struct gru_thread_state *gts) | |
695 | { | |
696 | if (gts->ts_tlb_int_select < 0 | |
697 | || gts->ts_tlb_int_select == gru_cpu_fault_map_id()) | |
698 | return 0; | |
699 | ||
700 | gru_dbg(grudev, "retarget from %d to %d\n", gts->ts_tlb_int_select, | |
701 | gru_cpu_fault_map_id()); | |
99f7c229 | 702 | return gru_update_cch(gts); |
9a0deecc JS |
703 | } |
704 | ||
41314790 JS |
705 | /* |
706 | * Check if a GRU context is allowed to use a specific chiplet. By default | |
707 | * a context is assigned to any blade-local chiplet. However, users can | |
708 | * override this. | |
709 | * Returns 1 if assignment allowed, 0 otherwise | |
710 | */ | |
711 | static int gru_check_chiplet_assignment(struct gru_state *gru, | |
712 | struct gru_thread_state *gts) | |
713 | { | |
714 | int blade_id; | |
715 | int chiplet_id; | |
716 | ||
717 | blade_id = gts->ts_user_blade_id; | |
718 | if (blade_id < 0) | |
719 | blade_id = uv_numa_blade_id(); | |
720 | ||
721 | chiplet_id = gts->ts_user_chiplet_id; | |
722 | return gru->gs_blade_id == blade_id && | |
723 | (chiplet_id < 0 || chiplet_id == gru->gs_chiplet_id); | |
724 | } | |
725 | ||
55484c45 JS |
726 | /* |
727 | * Unload the gru context if it is not assigned to the correct blade or | |
728 | * chiplet. Misassignment can occur if the process migrates to a different | |
729 | * blade or if the user changes the selected blade/chiplet. | |
55484c45 JS |
730 | */ |
731 | void gru_check_context_placement(struct gru_thread_state *gts) | |
732 | { | |
733 | struct gru_state *gru; | |
55484c45 JS |
734 | |
735 | /* | |
736 | * If the current task is the context owner, verify that the | |
737 | * context is correctly placed. This test is skipped for non-owner | |
738 | * references. Pthread apps use non-owner references to the CBRs. | |
739 | */ | |
740 | gru = gts->ts_gru; | |
741 | if (!gru || gts->ts_tgid_owner != current->tgid) | |
742 | return; | |
743 | ||
41314790 | 744 | if (!gru_check_chiplet_assignment(gru, gts)) { |
55484c45 JS |
745 | STAT(check_context_unload); |
746 | gru_unload_context(gts, 1); | |
747 | } else if (gru_retarget_intr(gts)) { | |
748 | STAT(check_context_retarget_intr); | |
749 | } | |
750 | } | |
751 | ||
9a0deecc JS |
752 | |
753 | /* | |
754 | * Insufficient GRU resources available on the local blade. Steal a context from | |
755 | * a process. This is a hack until a _real_ resource scheduler is written.... | |
756 | */ | |
757 | #define next_ctxnum(n) ((n) < GRU_NUM_CCH - 2 ? (n) + 1 : 0) | |
758 | #define next_gru(b, g) (((g) < &(b)->bs_grus[GRU_CHIPLETS_PER_BLADE - 1]) ? \ | |
759 | ((g)+1) : &(b)->bs_grus[0]) | |
760 | ||
836ce679 JS |
761 | static int is_gts_stealable(struct gru_thread_state *gts, |
762 | struct gru_blade_state *bs) | |
763 | { | |
764 | if (is_kernel_context(gts)) | |
765 | return down_write_trylock(&bs->bs_kgts_sema); | |
766 | else | |
767 | return mutex_trylock(>s->ts_ctxlock); | |
768 | } | |
769 | ||
770 | static void gts_stolen(struct gru_thread_state *gts, | |
771 | struct gru_blade_state *bs) | |
772 | { | |
773 | if (is_kernel_context(gts)) { | |
774 | up_write(&bs->bs_kgts_sema); | |
775 | STAT(steal_kernel_context); | |
776 | } else { | |
777 | mutex_unlock(>s->ts_ctxlock); | |
778 | STAT(steal_user_context); | |
779 | } | |
780 | } | |
781 | ||
55484c45 | 782 | void gru_steal_context(struct gru_thread_state *gts) |
9a0deecc JS |
783 | { |
784 | struct gru_blade_state *blade; | |
785 | struct gru_state *gru, *gru0; | |
786 | struct gru_thread_state *ngts = NULL; | |
787 | int ctxnum, ctxnum0, flag = 0, cbr, dsr; | |
41314790 | 788 | int blade_id; |
9a0deecc | 789 | |
41314790 | 790 | blade_id = gts->ts_user_blade_id; |
55484c45 JS |
791 | if (blade_id < 0) |
792 | blade_id = uv_numa_blade_id(); | |
9a0deecc JS |
793 | cbr = gts->ts_cbr_au_count; |
794 | dsr = gts->ts_dsr_au_count; | |
795 | ||
364b76df | 796 | blade = gru_base[blade_id]; |
9a0deecc JS |
797 | spin_lock(&blade->bs_lock); |
798 | ||
799 | ctxnum = next_ctxnum(blade->bs_lru_ctxnum); | |
800 | gru = blade->bs_lru_gru; | |
801 | if (ctxnum == 0) | |
802 | gru = next_gru(blade, gru); | |
55484c45 JS |
803 | blade->bs_lru_gru = gru; |
804 | blade->bs_lru_ctxnum = ctxnum; | |
9a0deecc JS |
805 | ctxnum0 = ctxnum; |
806 | gru0 = gru; | |
807 | while (1) { | |
41314790 | 808 | if (gru_check_chiplet_assignment(gru, gts)) { |
55484c45 | 809 | if (check_gru_resources(gru, cbr, dsr, GRU_NUM_CCH)) |
9a0deecc | 810 | break; |
55484c45 JS |
811 | spin_lock(&gru->gs_lock); |
812 | for (; ctxnum < GRU_NUM_CCH; ctxnum++) { | |
813 | if (flag && gru == gru0 && ctxnum == ctxnum0) | |
814 | break; | |
815 | ngts = gru->gs_gts[ctxnum]; | |
816 | /* | |
817 | * We are grabbing locks out of order, so trylock is | |
818 | * needed. GTSs are usually not locked, so the odds of | |
819 | * success are high. If trylock fails, try to steal a | |
820 | * different GSEG. | |
821 | */ | |
822 | if (ngts && is_gts_stealable(ngts, blade)) | |
823 | break; | |
824 | ngts = NULL; | |
825 | } | |
826 | spin_unlock(&gru->gs_lock); | |
827 | if (ngts || (flag && gru == gru0 && ctxnum == ctxnum0)) | |
9a0deecc | 828 | break; |
9a0deecc | 829 | } |
55484c45 | 830 | if (flag && gru == gru0) |
9a0deecc | 831 | break; |
55484c45 | 832 | flag = 1; |
9a0deecc JS |
833 | ctxnum = 0; |
834 | gru = next_gru(blade, gru); | |
835 | } | |
9a0deecc | 836 | spin_unlock(&blade->bs_lock); |
9a0deecc JS |
837 | |
838 | if (ngts) { | |
7e796a72 | 839 | gts->ustats.context_stolen++; |
9a0deecc | 840 | ngts->ts_steal_jiffies = jiffies; |
836ce679 JS |
841 | gru_unload_context(ngts, is_kernel_context(ngts) ? 0 : 1); |
842 | gts_stolen(ngts, blade); | |
9a0deecc JS |
843 | } else { |
844 | STAT(steal_context_failed); | |
845 | } | |
846 | gru_dbg(grudev, | |
43884604 | 847 | "stole gid %d, ctxnum %d from gts %p. Need cb %d, ds %d;" |
9a0deecc JS |
848 | " avail cb %ld, ds %ld\n", |
849 | gru->gs_gid, ctxnum, ngts, cbr, dsr, hweight64(gru->gs_cbr_map), | |
850 | hweight64(gru->gs_dsr_map)); | |
851 | } | |
852 | ||
55484c45 JS |
853 | /* |
854 | * Assign a gru context. | |
855 | */ | |
856 | static int gru_assign_context_number(struct gru_state *gru) | |
857 | { | |
858 | int ctxnum; | |
859 | ||
860 | ctxnum = find_first_zero_bit(&gru->gs_context_map, GRU_NUM_CCH); | |
861 | __set_bit(ctxnum, &gru->gs_context_map); | |
862 | return ctxnum; | |
863 | } | |
864 | ||
9a0deecc JS |
865 | /* |
866 | * Scan the GRUs on the local blade & assign a GRU context. | |
867 | */ | |
55484c45 | 868 | struct gru_state *gru_assign_gru_context(struct gru_thread_state *gts) |
9a0deecc JS |
869 | { |
870 | struct gru_state *gru, *grux; | |
871 | int i, max_active_contexts; | |
55484c45 | 872 | int blade_id = gts->ts_user_blade_id; |
9a0deecc | 873 | |
55484c45 JS |
874 | if (blade_id < 0) |
875 | blade_id = uv_numa_blade_id(); | |
9a0deecc JS |
876 | again: |
877 | gru = NULL; | |
878 | max_active_contexts = GRU_NUM_CCH; | |
55484c45 | 879 | for_each_gru_on_blade(grux, blade_id, i) { |
41314790 | 880 | if (!gru_check_chiplet_assignment(grux, gts)) |
55484c45 | 881 | continue; |
9a0deecc JS |
882 | if (check_gru_resources(grux, gts->ts_cbr_au_count, |
883 | gts->ts_dsr_au_count, | |
884 | max_active_contexts)) { | |
885 | gru = grux; | |
886 | max_active_contexts = grux->gs_active_contexts; | |
887 | if (max_active_contexts == 0) | |
888 | break; | |
889 | } | |
890 | } | |
891 | ||
892 | if (gru) { | |
893 | spin_lock(&gru->gs_lock); | |
894 | if (!check_gru_resources(gru, gts->ts_cbr_au_count, | |
895 | gts->ts_dsr_au_count, GRU_NUM_CCH)) { | |
896 | spin_unlock(&gru->gs_lock); | |
897 | goto again; | |
898 | } | |
899 | reserve_gru_resources(gru, gts); | |
900 | gts->ts_gru = gru; | |
87419412 | 901 | gts->ts_blade = gru->gs_blade_id; |
55484c45 | 902 | gts->ts_ctxnum = gru_assign_context_number(gru); |
9a0deecc JS |
903 | atomic_inc(>s->ts_refcnt); |
904 | gru->gs_gts[gts->ts_ctxnum] = gts; | |
9a0deecc JS |
905 | spin_unlock(&gru->gs_lock); |
906 | ||
907 | STAT(assign_context); | |
908 | gru_dbg(grudev, | |
43884604 | 909 | "gseg %p, gts %p, gid %d, ctx %d, cbr %d, dsr %d\n", |
9a0deecc JS |
910 | gseg_virtual_address(gts->ts_gru, gts->ts_ctxnum), gts, |
911 | gts->ts_gru->gs_gid, gts->ts_ctxnum, | |
912 | gts->ts_cbr_au_count, gts->ts_dsr_au_count); | |
913 | } else { | |
914 | gru_dbg(grudev, "failed to allocate a GTS %s\n", ""); | |
915 | STAT(assign_context_failed); | |
916 | } | |
917 | ||
9a0deecc JS |
918 | return gru; |
919 | } | |
920 | ||
921 | /* | |
922 | * gru_nopage | |
923 | * | |
924 | * Map the user's GRU segment | |
9ca8e40c JS |
925 | * |
926 | * Note: gru segments alway mmaped on GRU_GSEG_PAGESIZE boundaries. | |
9a0deecc JS |
927 | */ |
928 | int gru_fault(struct vm_area_struct *vma, struct vm_fault *vmf) | |
929 | { | |
930 | struct gru_thread_state *gts; | |
931 | unsigned long paddr, vaddr; | |
932 | ||
933 | vaddr = (unsigned long)vmf->virtual_address; | |
934 | gru_dbg(grudev, "vma %p, vaddr 0x%lx (0x%lx)\n", | |
935 | vma, vaddr, GSEG_BASE(vaddr)); | |
936 | STAT(nopfn); | |
937 | ||
9ca8e40c | 938 | /* The following check ensures vaddr is a valid address in the VMA */ |
9a0deecc JS |
939 | gts = gru_find_thread_state(vma, TSID(vaddr, vma)); |
940 | if (!gts) | |
941 | return VM_FAULT_SIGBUS; | |
942 | ||
943 | again: | |
9a0deecc | 944 | mutex_lock(>s->ts_ctxlock); |
fe5bb6b0 | 945 | preempt_disable(); |
364b76df | 946 | |
55484c45 | 947 | gru_check_context_placement(gts); |
9a0deecc JS |
948 | |
949 | if (!gts->ts_gru) { | |
836ce679 | 950 | STAT(load_user_context); |
55484c45 | 951 | if (!gru_assign_gru_context(gts)) { |
9a0deecc | 952 | preempt_enable(); |
364b76df JS |
953 | mutex_unlock(>s->ts_ctxlock); |
954 | set_current_state(TASK_INTERRUPTIBLE); | |
9a0deecc JS |
955 | schedule_timeout(GRU_ASSIGN_DELAY); /* true hack ZZZ */ |
956 | if (gts->ts_steal_jiffies + GRU_STEAL_DELAY < jiffies) | |
55484c45 | 957 | gru_steal_context(gts); |
9a0deecc JS |
958 | goto again; |
959 | } | |
960 | gru_load_context(gts); | |
961 | paddr = gseg_physical_address(gts->ts_gru, gts->ts_ctxnum); | |
962 | remap_pfn_range(vma, vaddr & ~(GRU_GSEG_PAGESIZE - 1), | |
963 | paddr >> PAGE_SHIFT, GRU_GSEG_PAGESIZE, | |
964 | vma->vm_page_prot); | |
965 | } | |
966 | ||
9a0deecc | 967 | preempt_enable(); |
364b76df | 968 | mutex_unlock(>s->ts_ctxlock); |
9a0deecc JS |
969 | |
970 | return VM_FAULT_NOPAGE; | |
971 | } | |
972 |