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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 | ||
17a3b050 JS |
33 | #include <linux/types.h> |
34 | #include <linux/kernel.h> | |
35 | #include <linux/module.h> | |
36 | #include <linux/init.h> | |
37 | #include <linux/errno.h> | |
38 | #include <linux/miscdevice.h> | |
39 | #include <linux/spinlock.h> | |
40 | #include <linux/mm.h> | |
41 | #include <linux/vmalloc.h> | |
42 | #include <linux/string.h> | |
43 | #include <linux/slab.h> | |
44 | #include <linux/numa.h> | |
45 | #include <asm/page.h> | |
46 | #include <asm/system.h> | |
47 | #include <asm/pgtable.h> | |
48 | #include <asm/atomic.h> | |
49 | #include <asm/tlbflush.h> | |
50 | #include <asm/uncached.h> | |
51 | #include <asm/sn/addrs.h> | |
52 | #include <asm/sn/arch.h> | |
53 | #include <asm/sn/mspec.h> | |
54 | #include <asm/sn/sn_cpuid.h> | |
55 | #include <asm/sn/io.h> | |
56 | #include <asm/sn/bte.h> | |
57 | #include <asm/sn/shubio.h> | |
58 | ||
59 | ||
60 | #define FETCHOP_ID "SGI Fetchop," | |
61 | #define CACHED_ID "Cached," | |
62 | #define UNCACHED_ID "Uncached" | |
63 | #define REVISION "4.0" | |
64 | #define MSPEC_BASENAME "mspec" | |
65 | ||
66 | /* | |
67 | * Page types allocated by the device. | |
68 | */ | |
69 | enum { | |
70 | MSPEC_FETCHOP = 1, | |
71 | MSPEC_CACHED, | |
72 | MSPEC_UNCACHED | |
73 | }; | |
74 | ||
1a4b0fc5 | 75 | #ifdef CONFIG_SGI_SN |
17a3b050 | 76 | static int is_sn2; |
1a4b0fc5 JS |
77 | #else |
78 | #define is_sn2 0 | |
79 | #endif | |
17a3b050 JS |
80 | |
81 | /* | |
82 | * One of these structures is allocated when an mspec region is mmaped. The | |
83 | * structure is pointed to by the vma->vm_private_data field in the vma struct. | |
84 | * This structure is used to record the addresses of the mspec pages. | |
85 | */ | |
86 | struct vma_data { | |
87 | atomic_t refcnt; /* Number of vmas sharing the data. */ | |
88 | spinlock_t lock; /* Serialize access to the vma. */ | |
89 | int count; /* Number of pages allocated. */ | |
90 | int type; /* Type of pages allocated. */ | |
91 | unsigned long maddr[0]; /* Array of MSPEC addresses. */ | |
92 | }; | |
93 | ||
94 | /* used on shub2 to clear FOP cache in the HUB */ | |
95 | static unsigned long scratch_page[MAX_NUMNODES]; | |
96 | #define SH2_AMO_CACHE_ENTRIES 4 | |
97 | ||
98 | static inline int | |
99 | mspec_zero_block(unsigned long addr, int len) | |
100 | { | |
101 | int status; | |
102 | ||
103 | if (is_sn2) { | |
104 | if (is_shub2()) { | |
105 | int nid; | |
106 | void *p; | |
107 | int i; | |
108 | ||
109 | nid = nasid_to_cnodeid(get_node_number(__pa(addr))); | |
110 | p = (void *)TO_AMO(scratch_page[nid]); | |
111 | ||
112 | for (i=0; i < SH2_AMO_CACHE_ENTRIES; i++) { | |
113 | FETCHOP_LOAD_OP(p, FETCHOP_LOAD); | |
114 | p += FETCHOP_VAR_SIZE; | |
115 | } | |
116 | } | |
117 | ||
118 | status = bte_copy(0, addr & ~__IA64_UNCACHED_OFFSET, len, | |
119 | BTE_WACQUIRE | BTE_ZERO_FILL, NULL); | |
120 | } else { | |
121 | memset((char *) addr, 0, len); | |
122 | status = 0; | |
123 | } | |
124 | return status; | |
125 | } | |
126 | ||
127 | /* | |
128 | * mspec_open | |
129 | * | |
130 | * Called when a device mapping is created by a means other than mmap | |
131 | * (via fork, etc.). Increments the reference count on the underlying | |
132 | * mspec data so it is not freed prematurely. | |
133 | */ | |
134 | static void | |
135 | mspec_open(struct vm_area_struct *vma) | |
136 | { | |
137 | struct vma_data *vdata; | |
138 | ||
139 | vdata = vma->vm_private_data; | |
140 | atomic_inc(&vdata->refcnt); | |
141 | } | |
142 | ||
143 | /* | |
144 | * mspec_close | |
145 | * | |
146 | * Called when unmapping a device mapping. Frees all mspec pages | |
147 | * belonging to the vma. | |
148 | */ | |
149 | static void | |
150 | mspec_close(struct vm_area_struct *vma) | |
151 | { | |
152 | struct vma_data *vdata; | |
153 | int i, pages, result, vdata_size; | |
154 | ||
155 | vdata = vma->vm_private_data; | |
156 | if (!atomic_dec_and_test(&vdata->refcnt)) | |
157 | return; | |
158 | ||
159 | pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; | |
160 | vdata_size = sizeof(struct vma_data) + pages * sizeof(long); | |
161 | for (i = 0; i < pages; i++) { | |
162 | if (vdata->maddr[i] == 0) | |
163 | continue; | |
164 | /* | |
165 | * Clear the page before sticking it back | |
166 | * into the pool. | |
167 | */ | |
168 | result = mspec_zero_block(vdata->maddr[i], PAGE_SIZE); | |
169 | if (!result) | |
170 | uncached_free_page(vdata->maddr[i]); | |
171 | else | |
172 | printk(KERN_WARNING "mspec_close(): " | |
173 | "failed to zero page %i\n", | |
174 | result); | |
175 | } | |
176 | ||
177 | if (vdata_size <= PAGE_SIZE) | |
178 | kfree(vdata); | |
179 | else | |
180 | vfree(vdata); | |
181 | } | |
182 | ||
183 | ||
184 | /* | |
185 | * mspec_nopfn | |
186 | * | |
187 | * Creates a mspec page and maps it to user space. | |
188 | */ | |
189 | static unsigned long | |
190 | mspec_nopfn(struct vm_area_struct *vma, unsigned long address) | |
191 | { | |
192 | unsigned long paddr, maddr; | |
193 | unsigned long pfn; | |
194 | int index; | |
195 | struct vma_data *vdata = vma->vm_private_data; | |
196 | ||
197 | index = (address - vma->vm_start) >> PAGE_SHIFT; | |
198 | maddr = (volatile unsigned long) vdata->maddr[index]; | |
199 | if (maddr == 0) { | |
200 | maddr = uncached_alloc_page(numa_node_id()); | |
201 | if (maddr == 0) | |
202 | return NOPFN_OOM; | |
203 | ||
204 | spin_lock(&vdata->lock); | |
205 | if (vdata->maddr[index] == 0) { | |
206 | vdata->count++; | |
207 | vdata->maddr[index] = maddr; | |
208 | } else { | |
209 | uncached_free_page(maddr); | |
210 | maddr = vdata->maddr[index]; | |
211 | } | |
212 | spin_unlock(&vdata->lock); | |
213 | } | |
214 | ||
215 | if (vdata->type == MSPEC_FETCHOP) | |
216 | paddr = TO_AMO(maddr); | |
217 | else | |
1a4b0fc5 | 218 | paddr = maddr & ~__IA64_UNCACHED_OFFSET; |
17a3b050 JS |
219 | |
220 | pfn = paddr >> PAGE_SHIFT; | |
221 | ||
222 | return pfn; | |
223 | } | |
224 | ||
225 | static struct vm_operations_struct mspec_vm_ops = { | |
226 | .open = mspec_open, | |
227 | .close = mspec_close, | |
228 | .nopfn = mspec_nopfn | |
229 | }; | |
230 | ||
231 | /* | |
232 | * mspec_mmap | |
233 | * | |
234 | * Called when mmaping the device. Initializes the vma with a fault handler | |
235 | * and private data structure necessary to allocate, track, and free the | |
236 | * underlying pages. | |
237 | */ | |
238 | static int | |
239 | mspec_mmap(struct file *file, struct vm_area_struct *vma, int type) | |
240 | { | |
241 | struct vma_data *vdata; | |
242 | int pages, vdata_size; | |
243 | ||
244 | if (vma->vm_pgoff != 0) | |
245 | return -EINVAL; | |
246 | ||
247 | if ((vma->vm_flags & VM_SHARED) == 0) | |
248 | return -EINVAL; | |
249 | ||
250 | if ((vma->vm_flags & VM_WRITE) == 0) | |
251 | return -EPERM; | |
252 | ||
253 | pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; | |
254 | vdata_size = sizeof(struct vma_data) + pages * sizeof(long); | |
255 | if (vdata_size <= PAGE_SIZE) | |
256 | vdata = kmalloc(vdata_size, GFP_KERNEL); | |
257 | else | |
258 | vdata = vmalloc(vdata_size); | |
259 | if (!vdata) | |
260 | return -ENOMEM; | |
261 | memset(vdata, 0, vdata_size); | |
262 | ||
263 | vdata->type = type; | |
264 | spin_lock_init(&vdata->lock); | |
265 | vdata->refcnt = ATOMIC_INIT(1); | |
266 | vma->vm_private_data = vdata; | |
267 | ||
268 | vma->vm_flags |= (VM_IO | VM_LOCKED | VM_RESERVED | VM_PFNMAP); | |
269 | if (vdata->type == MSPEC_FETCHOP || vdata->type == MSPEC_UNCACHED) | |
270 | vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); | |
271 | vma->vm_ops = &mspec_vm_ops; | |
272 | ||
273 | return 0; | |
274 | } | |
275 | ||
276 | static int | |
277 | fetchop_mmap(struct file *file, struct vm_area_struct *vma) | |
278 | { | |
279 | return mspec_mmap(file, vma, MSPEC_FETCHOP); | |
280 | } | |
281 | ||
282 | static int | |
283 | cached_mmap(struct file *file, struct vm_area_struct *vma) | |
284 | { | |
285 | return mspec_mmap(file, vma, MSPEC_CACHED); | |
286 | } | |
287 | ||
288 | static int | |
289 | uncached_mmap(struct file *file, struct vm_area_struct *vma) | |
290 | { | |
291 | return mspec_mmap(file, vma, MSPEC_UNCACHED); | |
292 | } | |
293 | ||
2b8693c0 | 294 | static const struct file_operations fetchop_fops = { |
17a3b050 JS |
295 | .owner = THIS_MODULE, |
296 | .mmap = fetchop_mmap | |
297 | }; | |
298 | ||
299 | static struct miscdevice fetchop_miscdev = { | |
300 | .minor = MISC_DYNAMIC_MINOR, | |
301 | .name = "sgi_fetchop", | |
302 | .fops = &fetchop_fops | |
303 | }; | |
304 | ||
2b8693c0 | 305 | static const struct file_operations cached_fops = { |
17a3b050 JS |
306 | .owner = THIS_MODULE, |
307 | .mmap = cached_mmap | |
308 | }; | |
309 | ||
310 | static struct miscdevice cached_miscdev = { | |
311 | .minor = MISC_DYNAMIC_MINOR, | |
312 | .name = "mspec_cached", | |
313 | .fops = &cached_fops | |
314 | }; | |
315 | ||
2b8693c0 | 316 | static const struct file_operations uncached_fops = { |
17a3b050 JS |
317 | .owner = THIS_MODULE, |
318 | .mmap = uncached_mmap | |
319 | }; | |
320 | ||
321 | static struct miscdevice uncached_miscdev = { | |
322 | .minor = MISC_DYNAMIC_MINOR, | |
323 | .name = "mspec_uncached", | |
324 | .fops = &uncached_fops | |
325 | }; | |
326 | ||
327 | /* | |
328 | * mspec_init | |
329 | * | |
330 | * Called at boot time to initialize the mspec facility. | |
331 | */ | |
332 | static int __init | |
333 | mspec_init(void) | |
334 | { | |
335 | int ret; | |
336 | int nid; | |
337 | ||
338 | /* | |
339 | * The fetchop device only works on SN2 hardware, uncached and cached | |
340 | * memory drivers should both be valid on all ia64 hardware | |
341 | */ | |
1a4b0fc5 | 342 | #ifdef CONFIG_SGI_SN |
17a3b050 JS |
343 | if (ia64_platform_is("sn2")) { |
344 | is_sn2 = 1; | |
345 | if (is_shub2()) { | |
346 | ret = -ENOMEM; | |
347 | for_each_online_node(nid) { | |
348 | int actual_nid; | |
349 | int nasid; | |
350 | unsigned long phys; | |
351 | ||
352 | scratch_page[nid] = uncached_alloc_page(nid); | |
353 | if (scratch_page[nid] == 0) | |
354 | goto free_scratch_pages; | |
355 | phys = __pa(scratch_page[nid]); | |
356 | nasid = get_node_number(phys); | |
357 | actual_nid = nasid_to_cnodeid(nasid); | |
358 | if (actual_nid != nid) | |
359 | goto free_scratch_pages; | |
360 | } | |
361 | } | |
362 | ||
363 | ret = misc_register(&fetchop_miscdev); | |
364 | if (ret) { | |
365 | printk(KERN_ERR | |
366 | "%s: failed to register device %i\n", | |
367 | FETCHOP_ID, ret); | |
368 | goto free_scratch_pages; | |
369 | } | |
370 | } | |
1a4b0fc5 | 371 | #endif |
17a3b050 JS |
372 | ret = misc_register(&cached_miscdev); |
373 | if (ret) { | |
374 | printk(KERN_ERR "%s: failed to register device %i\n", | |
375 | CACHED_ID, ret); | |
376 | if (is_sn2) | |
377 | misc_deregister(&fetchop_miscdev); | |
378 | goto free_scratch_pages; | |
379 | } | |
380 | ret = misc_register(&uncached_miscdev); | |
381 | if (ret) { | |
382 | printk(KERN_ERR "%s: failed to register device %i\n", | |
383 | UNCACHED_ID, ret); | |
384 | misc_deregister(&cached_miscdev); | |
385 | if (is_sn2) | |
386 | misc_deregister(&fetchop_miscdev); | |
387 | goto free_scratch_pages; | |
388 | } | |
389 | ||
390 | printk(KERN_INFO "%s %s initialized devices: %s %s %s\n", | |
391 | MSPEC_BASENAME, REVISION, is_sn2 ? FETCHOP_ID : "", | |
392 | CACHED_ID, UNCACHED_ID); | |
393 | ||
394 | return 0; | |
395 | ||
396 | free_scratch_pages: | |
397 | for_each_node(nid) { | |
398 | if (scratch_page[nid] != 0) | |
399 | uncached_free_page(scratch_page[nid]); | |
400 | } | |
401 | return ret; | |
402 | } | |
403 | ||
404 | static void __exit | |
405 | mspec_exit(void) | |
406 | { | |
407 | int nid; | |
408 | ||
409 | misc_deregister(&uncached_miscdev); | |
410 | misc_deregister(&cached_miscdev); | |
411 | if (is_sn2) { | |
412 | misc_deregister(&fetchop_miscdev); | |
413 | ||
414 | for_each_node(nid) { | |
415 | if (scratch_page[nid] != 0) | |
416 | uncached_free_page(scratch_page[nid]); | |
417 | } | |
418 | } | |
419 | } | |
420 | ||
421 | module_init(mspec_init); | |
422 | module_exit(mspec_exit); | |
423 | ||
424 | MODULE_AUTHOR("Silicon Graphics, Inc. <linux-altix@sgi.com>"); | |
425 | MODULE_DESCRIPTION("Driver for SGI SN special memory operations"); | |
426 | MODULE_LICENSE("GPL"); |