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17a3b050 JS |
1 | /* |
2 | * Copyright (C) 2001-2006 Silicon Graphics, Inc. All rights | |
3 | * reserved. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify it | |
6 | * under the terms of version 2 of the GNU General Public License | |
7 | * as published by the Free Software Foundation. | |
8 | */ | |
9 | ||
10 | /* | |
11 | * SN Platform Special Memory (mspec) Support | |
12 | * | |
13 | * This driver exports the SN special memory (mspec) facility to user | |
14 | * processes. | |
15 | * There are three types of memory made available thru this driver: | |
16 | * fetchops, uncached and cached. | |
17 | * | |
18 | * Fetchops are atomic memory operations that are implemented in the | |
19 | * memory controller on SGI SN hardware. | |
20 | * | |
21 | * Uncached are used for memory write combining feature of the ia64 | |
22 | * cpu. | |
23 | * | |
24 | * Cached are used for areas of memory that are used as cached addresses | |
25 | * on our partition and used as uncached addresses from other partitions. | |
26 | * Due to a design constraint of the SN2 Shub, you can not have processors | |
27 | * on the same FSB perform both a cached and uncached reference to the | |
28 | * same cache line. These special memory cached regions prevent the | |
29 | * kernel from ever dropping in a TLB entry and therefore prevent the | |
30 | * processor from ever speculating a cache line from this page. | |
31 | */ | |
32 | ||
33 | #include <linux/config.h> | |
34 | #include <linux/types.h> | |
35 | #include <linux/kernel.h> | |
36 | #include <linux/module.h> | |
37 | #include <linux/init.h> | |
38 | #include <linux/errno.h> | |
39 | #include <linux/miscdevice.h> | |
40 | #include <linux/spinlock.h> | |
41 | #include <linux/mm.h> | |
42 | #include <linux/vmalloc.h> | |
43 | #include <linux/string.h> | |
44 | #include <linux/slab.h> | |
45 | #include <linux/numa.h> | |
46 | #include <asm/page.h> | |
47 | #include <asm/system.h> | |
48 | #include <asm/pgtable.h> | |
49 | #include <asm/atomic.h> | |
50 | #include <asm/tlbflush.h> | |
51 | #include <asm/uncached.h> | |
52 | #include <asm/sn/addrs.h> | |
53 | #include <asm/sn/arch.h> | |
54 | #include <asm/sn/mspec.h> | |
55 | #include <asm/sn/sn_cpuid.h> | |
56 | #include <asm/sn/io.h> | |
57 | #include <asm/sn/bte.h> | |
58 | #include <asm/sn/shubio.h> | |
59 | ||
60 | ||
61 | #define FETCHOP_ID "SGI Fetchop," | |
62 | #define CACHED_ID "Cached," | |
63 | #define UNCACHED_ID "Uncached" | |
64 | #define REVISION "4.0" | |
65 | #define MSPEC_BASENAME "mspec" | |
66 | ||
67 | /* | |
68 | * Page types allocated by the device. | |
69 | */ | |
70 | enum { | |
71 | MSPEC_FETCHOP = 1, | |
72 | MSPEC_CACHED, | |
73 | MSPEC_UNCACHED | |
74 | }; | |
75 | ||
76 | static int is_sn2; | |
77 | ||
78 | /* | |
79 | * One of these structures is allocated when an mspec region is mmaped. The | |
80 | * structure is pointed to by the vma->vm_private_data field in the vma struct. | |
81 | * This structure is used to record the addresses of the mspec pages. | |
82 | */ | |
83 | struct vma_data { | |
84 | atomic_t refcnt; /* Number of vmas sharing the data. */ | |
85 | spinlock_t lock; /* Serialize access to the vma. */ | |
86 | int count; /* Number of pages allocated. */ | |
87 | int type; /* Type of pages allocated. */ | |
88 | unsigned long maddr[0]; /* Array of MSPEC addresses. */ | |
89 | }; | |
90 | ||
91 | /* used on shub2 to clear FOP cache in the HUB */ | |
92 | static unsigned long scratch_page[MAX_NUMNODES]; | |
93 | #define SH2_AMO_CACHE_ENTRIES 4 | |
94 | ||
95 | static inline int | |
96 | mspec_zero_block(unsigned long addr, int len) | |
97 | { | |
98 | int status; | |
99 | ||
100 | if (is_sn2) { | |
101 | if (is_shub2()) { | |
102 | int nid; | |
103 | void *p; | |
104 | int i; | |
105 | ||
106 | nid = nasid_to_cnodeid(get_node_number(__pa(addr))); | |
107 | p = (void *)TO_AMO(scratch_page[nid]); | |
108 | ||
109 | for (i=0; i < SH2_AMO_CACHE_ENTRIES; i++) { | |
110 | FETCHOP_LOAD_OP(p, FETCHOP_LOAD); | |
111 | p += FETCHOP_VAR_SIZE; | |
112 | } | |
113 | } | |
114 | ||
115 | status = bte_copy(0, addr & ~__IA64_UNCACHED_OFFSET, len, | |
116 | BTE_WACQUIRE | BTE_ZERO_FILL, NULL); | |
117 | } else { | |
118 | memset((char *) addr, 0, len); | |
119 | status = 0; | |
120 | } | |
121 | return status; | |
122 | } | |
123 | ||
124 | /* | |
125 | * mspec_open | |
126 | * | |
127 | * Called when a device mapping is created by a means other than mmap | |
128 | * (via fork, etc.). Increments the reference count on the underlying | |
129 | * mspec data so it is not freed prematurely. | |
130 | */ | |
131 | static void | |
132 | mspec_open(struct vm_area_struct *vma) | |
133 | { | |
134 | struct vma_data *vdata; | |
135 | ||
136 | vdata = vma->vm_private_data; | |
137 | atomic_inc(&vdata->refcnt); | |
138 | } | |
139 | ||
140 | /* | |
141 | * mspec_close | |
142 | * | |
143 | * Called when unmapping a device mapping. Frees all mspec pages | |
144 | * belonging to the vma. | |
145 | */ | |
146 | static void | |
147 | mspec_close(struct vm_area_struct *vma) | |
148 | { | |
149 | struct vma_data *vdata; | |
150 | int i, pages, result, vdata_size; | |
151 | ||
152 | vdata = vma->vm_private_data; | |
153 | if (!atomic_dec_and_test(&vdata->refcnt)) | |
154 | return; | |
155 | ||
156 | pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; | |
157 | vdata_size = sizeof(struct vma_data) + pages * sizeof(long); | |
158 | for (i = 0; i < pages; i++) { | |
159 | if (vdata->maddr[i] == 0) | |
160 | continue; | |
161 | /* | |
162 | * Clear the page before sticking it back | |
163 | * into the pool. | |
164 | */ | |
165 | result = mspec_zero_block(vdata->maddr[i], PAGE_SIZE); | |
166 | if (!result) | |
167 | uncached_free_page(vdata->maddr[i]); | |
168 | else | |
169 | printk(KERN_WARNING "mspec_close(): " | |
170 | "failed to zero page %i\n", | |
171 | result); | |
172 | } | |
173 | ||
174 | if (vdata_size <= PAGE_SIZE) | |
175 | kfree(vdata); | |
176 | else | |
177 | vfree(vdata); | |
178 | } | |
179 | ||
180 | ||
181 | /* | |
182 | * mspec_nopfn | |
183 | * | |
184 | * Creates a mspec page and maps it to user space. | |
185 | */ | |
186 | static unsigned long | |
187 | mspec_nopfn(struct vm_area_struct *vma, unsigned long address) | |
188 | { | |
189 | unsigned long paddr, maddr; | |
190 | unsigned long pfn; | |
191 | int index; | |
192 | struct vma_data *vdata = vma->vm_private_data; | |
193 | ||
194 | index = (address - vma->vm_start) >> PAGE_SHIFT; | |
195 | maddr = (volatile unsigned long) vdata->maddr[index]; | |
196 | if (maddr == 0) { | |
197 | maddr = uncached_alloc_page(numa_node_id()); | |
198 | if (maddr == 0) | |
199 | return NOPFN_OOM; | |
200 | ||
201 | spin_lock(&vdata->lock); | |
202 | if (vdata->maddr[index] == 0) { | |
203 | vdata->count++; | |
204 | vdata->maddr[index] = maddr; | |
205 | } else { | |
206 | uncached_free_page(maddr); | |
207 | maddr = vdata->maddr[index]; | |
208 | } | |
209 | spin_unlock(&vdata->lock); | |
210 | } | |
211 | ||
212 | if (vdata->type == MSPEC_FETCHOP) | |
213 | paddr = TO_AMO(maddr); | |
214 | else | |
215 | paddr = __pa(TO_CAC(maddr)); | |
216 | ||
217 | pfn = paddr >> PAGE_SHIFT; | |
218 | ||
219 | return pfn; | |
220 | } | |
221 | ||
222 | static struct vm_operations_struct mspec_vm_ops = { | |
223 | .open = mspec_open, | |
224 | .close = mspec_close, | |
225 | .nopfn = mspec_nopfn | |
226 | }; | |
227 | ||
228 | /* | |
229 | * mspec_mmap | |
230 | * | |
231 | * Called when mmaping the device. Initializes the vma with a fault handler | |
232 | * and private data structure necessary to allocate, track, and free the | |
233 | * underlying pages. | |
234 | */ | |
235 | static int | |
236 | mspec_mmap(struct file *file, struct vm_area_struct *vma, int type) | |
237 | { | |
238 | struct vma_data *vdata; | |
239 | int pages, vdata_size; | |
240 | ||
241 | if (vma->vm_pgoff != 0) | |
242 | return -EINVAL; | |
243 | ||
244 | if ((vma->vm_flags & VM_SHARED) == 0) | |
245 | return -EINVAL; | |
246 | ||
247 | if ((vma->vm_flags & VM_WRITE) == 0) | |
248 | return -EPERM; | |
249 | ||
250 | pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; | |
251 | vdata_size = sizeof(struct vma_data) + pages * sizeof(long); | |
252 | if (vdata_size <= PAGE_SIZE) | |
253 | vdata = kmalloc(vdata_size, GFP_KERNEL); | |
254 | else | |
255 | vdata = vmalloc(vdata_size); | |
256 | if (!vdata) | |
257 | return -ENOMEM; | |
258 | memset(vdata, 0, vdata_size); | |
259 | ||
260 | vdata->type = type; | |
261 | spin_lock_init(&vdata->lock); | |
262 | vdata->refcnt = ATOMIC_INIT(1); | |
263 | vma->vm_private_data = vdata; | |
264 | ||
265 | vma->vm_flags |= (VM_IO | VM_LOCKED | VM_RESERVED | VM_PFNMAP); | |
266 | if (vdata->type == MSPEC_FETCHOP || vdata->type == MSPEC_UNCACHED) | |
267 | vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); | |
268 | vma->vm_ops = &mspec_vm_ops; | |
269 | ||
270 | return 0; | |
271 | } | |
272 | ||
273 | static int | |
274 | fetchop_mmap(struct file *file, struct vm_area_struct *vma) | |
275 | { | |
276 | return mspec_mmap(file, vma, MSPEC_FETCHOP); | |
277 | } | |
278 | ||
279 | static int | |
280 | cached_mmap(struct file *file, struct vm_area_struct *vma) | |
281 | { | |
282 | return mspec_mmap(file, vma, MSPEC_CACHED); | |
283 | } | |
284 | ||
285 | static int | |
286 | uncached_mmap(struct file *file, struct vm_area_struct *vma) | |
287 | { | |
288 | return mspec_mmap(file, vma, MSPEC_UNCACHED); | |
289 | } | |
290 | ||
291 | static struct file_operations fetchop_fops = { | |
292 | .owner = THIS_MODULE, | |
293 | .mmap = fetchop_mmap | |
294 | }; | |
295 | ||
296 | static struct miscdevice fetchop_miscdev = { | |
297 | .minor = MISC_DYNAMIC_MINOR, | |
298 | .name = "sgi_fetchop", | |
299 | .fops = &fetchop_fops | |
300 | }; | |
301 | ||
302 | static struct file_operations cached_fops = { | |
303 | .owner = THIS_MODULE, | |
304 | .mmap = cached_mmap | |
305 | }; | |
306 | ||
307 | static struct miscdevice cached_miscdev = { | |
308 | .minor = MISC_DYNAMIC_MINOR, | |
309 | .name = "mspec_cached", | |
310 | .fops = &cached_fops | |
311 | }; | |
312 | ||
313 | static struct file_operations uncached_fops = { | |
314 | .owner = THIS_MODULE, | |
315 | .mmap = uncached_mmap | |
316 | }; | |
317 | ||
318 | static struct miscdevice uncached_miscdev = { | |
319 | .minor = MISC_DYNAMIC_MINOR, | |
320 | .name = "mspec_uncached", | |
321 | .fops = &uncached_fops | |
322 | }; | |
323 | ||
324 | /* | |
325 | * mspec_init | |
326 | * | |
327 | * Called at boot time to initialize the mspec facility. | |
328 | */ | |
329 | static int __init | |
330 | mspec_init(void) | |
331 | { | |
332 | int ret; | |
333 | int nid; | |
334 | ||
335 | /* | |
336 | * The fetchop device only works on SN2 hardware, uncached and cached | |
337 | * memory drivers should both be valid on all ia64 hardware | |
338 | */ | |
339 | if (ia64_platform_is("sn2")) { | |
340 | is_sn2 = 1; | |
341 | if (is_shub2()) { | |
342 | ret = -ENOMEM; | |
343 | for_each_online_node(nid) { | |
344 | int actual_nid; | |
345 | int nasid; | |
346 | unsigned long phys; | |
347 | ||
348 | scratch_page[nid] = uncached_alloc_page(nid); | |
349 | if (scratch_page[nid] == 0) | |
350 | goto free_scratch_pages; | |
351 | phys = __pa(scratch_page[nid]); | |
352 | nasid = get_node_number(phys); | |
353 | actual_nid = nasid_to_cnodeid(nasid); | |
354 | if (actual_nid != nid) | |
355 | goto free_scratch_pages; | |
356 | } | |
357 | } | |
358 | ||
359 | ret = misc_register(&fetchop_miscdev); | |
360 | if (ret) { | |
361 | printk(KERN_ERR | |
362 | "%s: failed to register device %i\n", | |
363 | FETCHOP_ID, ret); | |
364 | goto free_scratch_pages; | |
365 | } | |
366 | } | |
367 | ret = misc_register(&cached_miscdev); | |
368 | if (ret) { | |
369 | printk(KERN_ERR "%s: failed to register device %i\n", | |
370 | CACHED_ID, ret); | |
371 | if (is_sn2) | |
372 | misc_deregister(&fetchop_miscdev); | |
373 | goto free_scratch_pages; | |
374 | } | |
375 | ret = misc_register(&uncached_miscdev); | |
376 | if (ret) { | |
377 | printk(KERN_ERR "%s: failed to register device %i\n", | |
378 | UNCACHED_ID, ret); | |
379 | misc_deregister(&cached_miscdev); | |
380 | if (is_sn2) | |
381 | misc_deregister(&fetchop_miscdev); | |
382 | goto free_scratch_pages; | |
383 | } | |
384 | ||
385 | printk(KERN_INFO "%s %s initialized devices: %s %s %s\n", | |
386 | MSPEC_BASENAME, REVISION, is_sn2 ? FETCHOP_ID : "", | |
387 | CACHED_ID, UNCACHED_ID); | |
388 | ||
389 | return 0; | |
390 | ||
391 | free_scratch_pages: | |
392 | for_each_node(nid) { | |
393 | if (scratch_page[nid] != 0) | |
394 | uncached_free_page(scratch_page[nid]); | |
395 | } | |
396 | return ret; | |
397 | } | |
398 | ||
399 | static void __exit | |
400 | mspec_exit(void) | |
401 | { | |
402 | int nid; | |
403 | ||
404 | misc_deregister(&uncached_miscdev); | |
405 | misc_deregister(&cached_miscdev); | |
406 | if (is_sn2) { | |
407 | misc_deregister(&fetchop_miscdev); | |
408 | ||
409 | for_each_node(nid) { | |
410 | if (scratch_page[nid] != 0) | |
411 | uncached_free_page(scratch_page[nid]); | |
412 | } | |
413 | } | |
414 | } | |
415 | ||
416 | module_init(mspec_init); | |
417 | module_exit(mspec_exit); | |
418 | ||
419 | MODULE_AUTHOR("Silicon Graphics, Inc. <linux-altix@sgi.com>"); | |
420 | MODULE_DESCRIPTION("Driver for SGI SN special memory operations"); | |
421 | MODULE_LICENSE("GPL"); |