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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/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/fs.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/pgtable.h> | |
48 | #include <linux/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 mspec_page_type { | |
70 | MSPEC_FETCHOP = 1, | |
71 | MSPEC_CACHED, | |
72 | MSPEC_UNCACHED | |
73 | }; | |
74 | ||
75 | #ifdef CONFIG_SGI_SN | |
76 | static int is_sn2; | |
77 | #else | |
78 | #define is_sn2 0 | |
79 | #endif | |
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 | * This structure is shared by all vma's that are split off from the | |
86 | * original vma when split_vma()'s are done. | |
87 | * | |
88 | * The refcnt is incremented atomically because mm->mmap_sem does not | |
89 | * protect in fork case where multiple tasks share the vma_data. | |
90 | */ | |
91 | struct vma_data { | |
92 | atomic_t refcnt; /* Number of vmas sharing the data. */ | |
93 | spinlock_t lock; /* Serialize access to this structure. */ | |
94 | int count; /* Number of pages allocated. */ | |
95 | enum mspec_page_type type; /* Type of pages allocated. */ | |
96 | unsigned long vm_start; /* Original (unsplit) base. */ | |
97 | unsigned long vm_end; /* Original (unsplit) end. */ | |
98 | unsigned long maddr[0]; /* Array of MSPEC addresses. */ | |
99 | }; | |
100 | ||
101 | /* used on shub2 to clear FOP cache in the HUB */ | |
102 | static unsigned long scratch_page[MAX_NUMNODES]; | |
103 | #define SH2_AMO_CACHE_ENTRIES 4 | |
104 | ||
105 | static inline int | |
106 | mspec_zero_block(unsigned long addr, int len) | |
107 | { | |
108 | int status; | |
109 | ||
110 | if (is_sn2) { | |
111 | if (is_shub2()) { | |
112 | int nid; | |
113 | void *p; | |
114 | int i; | |
115 | ||
116 | nid = nasid_to_cnodeid(get_node_number(__pa(addr))); | |
117 | p = (void *)TO_AMO(scratch_page[nid]); | |
118 | ||
119 | for (i=0; i < SH2_AMO_CACHE_ENTRIES; i++) { | |
120 | FETCHOP_LOAD_OP(p, FETCHOP_LOAD); | |
121 | p += FETCHOP_VAR_SIZE; | |
122 | } | |
123 | } | |
124 | ||
125 | status = bte_copy(0, addr & ~__IA64_UNCACHED_OFFSET, len, | |
126 | BTE_WACQUIRE | BTE_ZERO_FILL, NULL); | |
127 | } else { | |
128 | memset((char *) addr, 0, len); | |
129 | status = 0; | |
130 | } | |
131 | return status; | |
132 | } | |
133 | ||
134 | /* | |
135 | * mspec_open | |
136 | * | |
137 | * Called when a device mapping is created by a means other than mmap | |
138 | * (via fork, munmap, etc.). Increments the reference count on the | |
139 | * underlying mspec data so it is not freed prematurely. | |
140 | */ | |
141 | static void | |
142 | mspec_open(struct vm_area_struct *vma) | |
143 | { | |
144 | struct vma_data *vdata; | |
145 | ||
146 | vdata = vma->vm_private_data; | |
147 | atomic_inc(&vdata->refcnt); | |
148 | } | |
149 | ||
150 | /* | |
151 | * mspec_close | |
152 | * | |
153 | * Called when unmapping a device mapping. Frees all mspec pages | |
154 | * belonging to all the vma's sharing this vma_data structure. | |
155 | */ | |
156 | static void | |
157 | mspec_close(struct vm_area_struct *vma) | |
158 | { | |
159 | struct vma_data *vdata; | |
160 | int index, last_index; | |
161 | unsigned long my_page; | |
162 | ||
163 | vdata = vma->vm_private_data; | |
164 | ||
165 | if (!atomic_dec_and_test(&vdata->refcnt)) | |
166 | return; | |
167 | ||
168 | last_index = (vdata->vm_end - vdata->vm_start) >> PAGE_SHIFT; | |
169 | for (index = 0; index < last_index; index++) { | |
170 | if (vdata->maddr[index] == 0) | |
171 | continue; | |
172 | /* | |
173 | * Clear the page before sticking it back | |
174 | * into the pool. | |
175 | */ | |
176 | my_page = vdata->maddr[index]; | |
177 | vdata->maddr[index] = 0; | |
178 | if (!mspec_zero_block(my_page, PAGE_SIZE)) | |
179 | uncached_free_page(my_page, 1); | |
180 | else | |
181 | printk(KERN_WARNING "mspec_close(): " | |
182 | "failed to zero page %ld\n", my_page); | |
183 | } | |
184 | ||
185 | kvfree(vdata); | |
186 | } | |
187 | ||
188 | /* | |
189 | * mspec_fault | |
190 | * | |
191 | * Creates a mspec page and maps it to user space. | |
192 | */ | |
193 | static int | |
194 | mspec_fault(struct vm_area_struct *vma, struct vm_fault *vmf) | |
195 | { | |
196 | unsigned long paddr, maddr; | |
197 | unsigned long pfn; | |
198 | pgoff_t index = vmf->pgoff; | |
199 | struct vma_data *vdata = vma->vm_private_data; | |
200 | ||
201 | maddr = (volatile unsigned long) vdata->maddr[index]; | |
202 | if (maddr == 0) { | |
203 | maddr = uncached_alloc_page(numa_node_id(), 1); | |
204 | if (maddr == 0) | |
205 | return VM_FAULT_OOM; | |
206 | ||
207 | spin_lock(&vdata->lock); | |
208 | if (vdata->maddr[index] == 0) { | |
209 | vdata->count++; | |
210 | vdata->maddr[index] = maddr; | |
211 | } else { | |
212 | uncached_free_page(maddr, 1); | |
213 | maddr = vdata->maddr[index]; | |
214 | } | |
215 | spin_unlock(&vdata->lock); | |
216 | } | |
217 | ||
218 | if (vdata->type == MSPEC_FETCHOP) | |
219 | paddr = TO_AMO(maddr); | |
220 | else | |
221 | paddr = maddr & ~__IA64_UNCACHED_OFFSET; | |
222 | ||
223 | pfn = paddr >> PAGE_SHIFT; | |
224 | ||
225 | /* | |
226 | * vm_insert_pfn can fail with -EBUSY, but in that case it will | |
227 | * be because another thread has installed the pte first, so it | |
228 | * is no problem. | |
229 | */ | |
230 | vm_insert_pfn(vma, (unsigned long)vmf->virtual_address, pfn); | |
231 | ||
232 | return VM_FAULT_NOPAGE; | |
233 | } | |
234 | ||
235 | static const struct vm_operations_struct mspec_vm_ops = { | |
236 | .open = mspec_open, | |
237 | .close = mspec_close, | |
238 | .fault = mspec_fault, | |
239 | }; | |
240 | ||
241 | /* | |
242 | * mspec_mmap | |
243 | * | |
244 | * Called when mmapping the device. Initializes the vma with a fault handler | |
245 | * and private data structure necessary to allocate, track, and free the | |
246 | * underlying pages. | |
247 | */ | |
248 | static int | |
249 | mspec_mmap(struct file *file, struct vm_area_struct *vma, | |
250 | enum mspec_page_type type) | |
251 | { | |
252 | struct vma_data *vdata; | |
253 | int pages, vdata_size; | |
254 | ||
255 | if (vma->vm_pgoff != 0) | |
256 | return -EINVAL; | |
257 | ||
258 | if ((vma->vm_flags & VM_SHARED) == 0) | |
259 | return -EINVAL; | |
260 | ||
261 | if ((vma->vm_flags & VM_WRITE) == 0) | |
262 | return -EPERM; | |
263 | ||
264 | pages = vma_pages(vma); | |
265 | vdata_size = sizeof(struct vma_data) + pages * sizeof(long); | |
266 | if (vdata_size <= PAGE_SIZE) | |
267 | vdata = kzalloc(vdata_size, GFP_KERNEL); | |
268 | else | |
269 | vdata = vzalloc(vdata_size); | |
270 | if (!vdata) | |
271 | return -ENOMEM; | |
272 | ||
273 | vdata->vm_start = vma->vm_start; | |
274 | vdata->vm_end = vma->vm_end; | |
275 | vdata->type = type; | |
276 | spin_lock_init(&vdata->lock); | |
277 | atomic_set(&vdata->refcnt, 1); | |
278 | vma->vm_private_data = vdata; | |
279 | ||
280 | vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; | |
281 | if (vdata->type == MSPEC_FETCHOP || vdata->type == MSPEC_UNCACHED) | |
282 | vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); | |
283 | vma->vm_ops = &mspec_vm_ops; | |
284 | ||
285 | return 0; | |
286 | } | |
287 | ||
288 | static int | |
289 | fetchop_mmap(struct file *file, struct vm_area_struct *vma) | |
290 | { | |
291 | return mspec_mmap(file, vma, MSPEC_FETCHOP); | |
292 | } | |
293 | ||
294 | static int | |
295 | cached_mmap(struct file *file, struct vm_area_struct *vma) | |
296 | { | |
297 | return mspec_mmap(file, vma, MSPEC_CACHED); | |
298 | } | |
299 | ||
300 | static int | |
301 | uncached_mmap(struct file *file, struct vm_area_struct *vma) | |
302 | { | |
303 | return mspec_mmap(file, vma, MSPEC_UNCACHED); | |
304 | } | |
305 | ||
306 | static const struct file_operations fetchop_fops = { | |
307 | .owner = THIS_MODULE, | |
308 | .mmap = fetchop_mmap, | |
309 | .llseek = noop_llseek, | |
310 | }; | |
311 | ||
312 | static struct miscdevice fetchop_miscdev = { | |
313 | .minor = MISC_DYNAMIC_MINOR, | |
314 | .name = "sgi_fetchop", | |
315 | .fops = &fetchop_fops | |
316 | }; | |
317 | ||
318 | static const struct file_operations cached_fops = { | |
319 | .owner = THIS_MODULE, | |
320 | .mmap = cached_mmap, | |
321 | .llseek = noop_llseek, | |
322 | }; | |
323 | ||
324 | static struct miscdevice cached_miscdev = { | |
325 | .minor = MISC_DYNAMIC_MINOR, | |
326 | .name = "mspec_cached", | |
327 | .fops = &cached_fops | |
328 | }; | |
329 | ||
330 | static const struct file_operations uncached_fops = { | |
331 | .owner = THIS_MODULE, | |
332 | .mmap = uncached_mmap, | |
333 | .llseek = noop_llseek, | |
334 | }; | |
335 | ||
336 | static struct miscdevice uncached_miscdev = { | |
337 | .minor = MISC_DYNAMIC_MINOR, | |
338 | .name = "mspec_uncached", | |
339 | .fops = &uncached_fops | |
340 | }; | |
341 | ||
342 | /* | |
343 | * mspec_init | |
344 | * | |
345 | * Called at boot time to initialize the mspec facility. | |
346 | */ | |
347 | static int __init | |
348 | mspec_init(void) | |
349 | { | |
350 | int ret; | |
351 | int nid; | |
352 | ||
353 | /* | |
354 | * The fetchop device only works on SN2 hardware, uncached and cached | |
355 | * memory drivers should both be valid on all ia64 hardware | |
356 | */ | |
357 | #ifdef CONFIG_SGI_SN | |
358 | if (ia64_platform_is("sn2")) { | |
359 | is_sn2 = 1; | |
360 | if (is_shub2()) { | |
361 | ret = -ENOMEM; | |
362 | for_each_node_state(nid, N_ONLINE) { | |
363 | int actual_nid; | |
364 | int nasid; | |
365 | unsigned long phys; | |
366 | ||
367 | scratch_page[nid] = uncached_alloc_page(nid, 1); | |
368 | if (scratch_page[nid] == 0) | |
369 | goto free_scratch_pages; | |
370 | phys = __pa(scratch_page[nid]); | |
371 | nasid = get_node_number(phys); | |
372 | actual_nid = nasid_to_cnodeid(nasid); | |
373 | if (actual_nid != nid) | |
374 | goto free_scratch_pages; | |
375 | } | |
376 | } | |
377 | ||
378 | ret = misc_register(&fetchop_miscdev); | |
379 | if (ret) { | |
380 | printk(KERN_ERR | |
381 | "%s: failed to register device %i\n", | |
382 | FETCHOP_ID, ret); | |
383 | goto free_scratch_pages; | |
384 | } | |
385 | } | |
386 | #endif | |
387 | ret = misc_register(&cached_miscdev); | |
388 | if (ret) { | |
389 | printk(KERN_ERR "%s: failed to register device %i\n", | |
390 | CACHED_ID, ret); | |
391 | if (is_sn2) | |
392 | misc_deregister(&fetchop_miscdev); | |
393 | goto free_scratch_pages; | |
394 | } | |
395 | ret = misc_register(&uncached_miscdev); | |
396 | if (ret) { | |
397 | printk(KERN_ERR "%s: failed to register device %i\n", | |
398 | UNCACHED_ID, ret); | |
399 | misc_deregister(&cached_miscdev); | |
400 | if (is_sn2) | |
401 | misc_deregister(&fetchop_miscdev); | |
402 | goto free_scratch_pages; | |
403 | } | |
404 | ||
405 | printk(KERN_INFO "%s %s initialized devices: %s %s %s\n", | |
406 | MSPEC_BASENAME, REVISION, is_sn2 ? FETCHOP_ID : "", | |
407 | CACHED_ID, UNCACHED_ID); | |
408 | ||
409 | return 0; | |
410 | ||
411 | free_scratch_pages: | |
412 | for_each_node(nid) { | |
413 | if (scratch_page[nid] != 0) | |
414 | uncached_free_page(scratch_page[nid], 1); | |
415 | } | |
416 | return ret; | |
417 | } | |
418 | ||
419 | static void __exit | |
420 | mspec_exit(void) | |
421 | { | |
422 | int nid; | |
423 | ||
424 | misc_deregister(&uncached_miscdev); | |
425 | misc_deregister(&cached_miscdev); | |
426 | if (is_sn2) { | |
427 | misc_deregister(&fetchop_miscdev); | |
428 | ||
429 | for_each_node(nid) { | |
430 | if (scratch_page[nid] != 0) | |
431 | uncached_free_page(scratch_page[nid], 1); | |
432 | } | |
433 | } | |
434 | } | |
435 | ||
436 | module_init(mspec_init); | |
437 | module_exit(mspec_exit); | |
438 | ||
439 | MODULE_AUTHOR("Silicon Graphics, Inc. <linux-altix@sgi.com>"); | |
440 | MODULE_DESCRIPTION("Driver for SGI SN special memory operations"); | |
441 | MODULE_LICENSE("GPL"); |