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Jes Sorensen17a3b052006-09-27 01:50:11 -07001/*
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
Jes Sorensen17a3b052006-09-27 01:50:11 -070033#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>
Alexey Dobriyan4e950f62007-07-30 02:36:13 +040041#include <linux/fs.h>
Jes Sorensen17a3b052006-09-27 01:50:11 -070042#include <linux/vmalloc.h>
43#include <linux/string.h>
44#include <linux/slab.h>
45#include <linux/numa.h>
46#include <asm/page.h>
Jes Sorensen17a3b052006-09-27 01:50:11 -070047#include <asm/pgtable.h>
Arun Sharma600634972011-07-26 16:09:06 -070048#include <linux/atomic.h>
Jes Sorensen17a3b052006-09-27 01:50:11 -070049#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 */
Cliff Wickman4191ba22007-09-18 22:46:31 -070069enum mspec_page_type {
Jes Sorensen17a3b052006-09-27 01:50:11 -070070 MSPEC_FETCHOP = 1,
71 MSPEC_CACHED,
72 MSPEC_UNCACHED
73};
74
Jes Sorensen1a4b0fc2006-11-10 12:27:49 -080075#ifdef CONFIG_SGI_SN
Jes Sorensen17a3b052006-09-27 01:50:11 -070076static int is_sn2;
Jes Sorensen1a4b0fc2006-11-10 12:27:49 -080077#else
78#define is_sn2 0
79#endif
Jes Sorensen17a3b052006-09-27 01:50:11 -070080
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.
Cliff Wickman4191ba22007-09-18 22:46:31 -070085 * 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.
Jes Sorensen17a3b052006-09-27 01:50:11 -070090 */
91struct vma_data {
92 atomic_t refcnt; /* Number of vmas sharing the data. */
Cliff Wickman4191ba22007-09-18 22:46:31 -070093 spinlock_t lock; /* Serialize access to this structure. */
Jes Sorensen17a3b052006-09-27 01:50:11 -070094 int count; /* Number of pages allocated. */
Cliff Wickman4191ba22007-09-18 22:46:31 -070095 enum mspec_page_type type; /* Type of pages allocated. */
96 int flags; /* See VMD_xxx below. */
97 unsigned long vm_start; /* Original (unsplit) base. */
98 unsigned long vm_end; /* Original (unsplit) end. */
Jes Sorensen17a3b052006-09-27 01:50:11 -070099 unsigned long maddr[0]; /* Array of MSPEC addresses. */
100};
101
Cliff Wickman4191ba22007-09-18 22:46:31 -0700102#define VMD_VMALLOCED 0x1 /* vmalloc'd rather than kmalloc'd */
103
Jes Sorensen17a3b052006-09-27 01:50:11 -0700104/* used on shub2 to clear FOP cache in the HUB */
105static unsigned long scratch_page[MAX_NUMNODES];
106#define SH2_AMO_CACHE_ENTRIES 4
107
108static inline int
109mspec_zero_block(unsigned long addr, int len)
110{
111 int status;
112
113 if (is_sn2) {
114 if (is_shub2()) {
115 int nid;
116 void *p;
117 int i;
118
119 nid = nasid_to_cnodeid(get_node_number(__pa(addr)));
120 p = (void *)TO_AMO(scratch_page[nid]);
121
122 for (i=0; i < SH2_AMO_CACHE_ENTRIES; i++) {
123 FETCHOP_LOAD_OP(p, FETCHOP_LOAD);
124 p += FETCHOP_VAR_SIZE;
125 }
126 }
127
128 status = bte_copy(0, addr & ~__IA64_UNCACHED_OFFSET, len,
129 BTE_WACQUIRE | BTE_ZERO_FILL, NULL);
130 } else {
131 memset((char *) addr, 0, len);
132 status = 0;
133 }
134 return status;
135}
136
137/*
138 * mspec_open
139 *
140 * Called when a device mapping is created by a means other than mmap
Cliff Wickman4191ba22007-09-18 22:46:31 -0700141 * (via fork, munmap, etc.). Increments the reference count on the
142 * underlying mspec data so it is not freed prematurely.
Jes Sorensen17a3b052006-09-27 01:50:11 -0700143 */
144static void
145mspec_open(struct vm_area_struct *vma)
146{
147 struct vma_data *vdata;
148
149 vdata = vma->vm_private_data;
150 atomic_inc(&vdata->refcnt);
151}
152
153/*
154 * mspec_close
155 *
156 * Called when unmapping a device mapping. Frees all mspec pages
Cliff Wickmanafa684f2007-09-24 21:24:41 -0700157 * belonging to all the vma's sharing this vma_data structure.
Jes Sorensen17a3b052006-09-27 01:50:11 -0700158 */
159static void
160mspec_close(struct vm_area_struct *vma)
161{
162 struct vma_data *vdata;
Cliff Wickmanafa684f2007-09-24 21:24:41 -0700163 int index, last_index;
Cliff Wickman4191ba22007-09-18 22:46:31 -0700164 unsigned long my_page;
Jes Sorensen17a3b052006-09-27 01:50:11 -0700165
166 vdata = vma->vm_private_data;
Jes Sorensen17a3b052006-09-27 01:50:11 -0700167
Cliff Wickmanafa684f2007-09-24 21:24:41 -0700168 if (!atomic_dec_and_test(&vdata->refcnt))
169 return;
Cliff Wickman4191ba22007-09-18 22:46:31 -0700170
Cliff Wickmanafa684f2007-09-24 21:24:41 -0700171 last_index = (vdata->vm_end - vdata->vm_start) >> PAGE_SHIFT;
172 for (index = 0; index < last_index; index++) {
Cliff Wickman4191ba22007-09-18 22:46:31 -0700173 if (vdata->maddr[index] == 0)
Jes Sorensen17a3b052006-09-27 01:50:11 -0700174 continue;
175 /*
176 * Clear the page before sticking it back
177 * into the pool.
178 */
Cliff Wickman4191ba22007-09-18 22:46:31 -0700179 my_page = vdata->maddr[index];
180 vdata->maddr[index] = 0;
Cliff Wickmanafa684f2007-09-24 21:24:41 -0700181 if (!mspec_zero_block(my_page, PAGE_SIZE))
Dean Nelsone4a064d2008-04-25 15:22:19 -0500182 uncached_free_page(my_page, 1);
Jes Sorensen17a3b052006-09-27 01:50:11 -0700183 else
184 printk(KERN_WARNING "mspec_close(): "
Cliff Wickmanafa684f2007-09-24 21:24:41 -0700185 "failed to zero page %ld\n", my_page);
Jes Sorensen17a3b052006-09-27 01:50:11 -0700186 }
Cliff Wickman4191ba22007-09-18 22:46:31 -0700187
188 if (vdata->flags & VMD_VMALLOCED)
Jes Sorensen17a3b052006-09-27 01:50:11 -0700189 vfree(vdata);
Cliff Wickman4191ba22007-09-18 22:46:31 -0700190 else
191 kfree(vdata);
Jes Sorensen17a3b052006-09-27 01:50:11 -0700192}
193
Jes Sorensen17a3b052006-09-27 01:50:11 -0700194/*
Nick Pigginefe9e772008-07-23 21:27:00 -0700195 * mspec_fault
Jes Sorensen17a3b052006-09-27 01:50:11 -0700196 *
197 * Creates a mspec page and maps it to user space.
198 */
Nick Pigginefe9e772008-07-23 21:27:00 -0700199static int
200mspec_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
Jes Sorensen17a3b052006-09-27 01:50:11 -0700201{
202 unsigned long paddr, maddr;
203 unsigned long pfn;
Nick Pigginefe9e772008-07-23 21:27:00 -0700204 pgoff_t index = vmf->pgoff;
Jes Sorensen17a3b052006-09-27 01:50:11 -0700205 struct vma_data *vdata = vma->vm_private_data;
206
Jes Sorensen17a3b052006-09-27 01:50:11 -0700207 maddr = (volatile unsigned long) vdata->maddr[index];
208 if (maddr == 0) {
Dean Nelsone4a064d2008-04-25 15:22:19 -0500209 maddr = uncached_alloc_page(numa_node_id(), 1);
Jes Sorensen17a3b052006-09-27 01:50:11 -0700210 if (maddr == 0)
Nick Pigginefe9e772008-07-23 21:27:00 -0700211 return VM_FAULT_OOM;
Jes Sorensen17a3b052006-09-27 01:50:11 -0700212
213 spin_lock(&vdata->lock);
214 if (vdata->maddr[index] == 0) {
215 vdata->count++;
216 vdata->maddr[index] = maddr;
217 } else {
Dean Nelsone4a064d2008-04-25 15:22:19 -0500218 uncached_free_page(maddr, 1);
Jes Sorensen17a3b052006-09-27 01:50:11 -0700219 maddr = vdata->maddr[index];
220 }
221 spin_unlock(&vdata->lock);
222 }
223
224 if (vdata->type == MSPEC_FETCHOP)
225 paddr = TO_AMO(maddr);
226 else
Jes Sorensen1a4b0fc2006-11-10 12:27:49 -0800227 paddr = maddr & ~__IA64_UNCACHED_OFFSET;
Jes Sorensen17a3b052006-09-27 01:50:11 -0700228
229 pfn = paddr >> PAGE_SHIFT;
230
Nick Pigginefe9e772008-07-23 21:27:00 -0700231 /*
232 * vm_insert_pfn can fail with -EBUSY, but in that case it will
233 * be because another thread has installed the pte first, so it
234 * is no problem.
235 */
236 vm_insert_pfn(vma, (unsigned long)vmf->virtual_address, pfn);
237
238 return VM_FAULT_NOPAGE;
Jes Sorensen17a3b052006-09-27 01:50:11 -0700239}
240
Alexey Dobriyanf0f37e22009-09-27 22:29:37 +0400241static const struct vm_operations_struct mspec_vm_ops = {
Jes Sorensen17a3b052006-09-27 01:50:11 -0700242 .open = mspec_open,
243 .close = mspec_close,
Nick Pigginefe9e772008-07-23 21:27:00 -0700244 .fault = mspec_fault,
Jes Sorensen17a3b052006-09-27 01:50:11 -0700245};
246
247/*
248 * mspec_mmap
249 *
André Goddard Rosaaf901ca2009-11-14 13:09:05 -0200250 * Called when mmapping the device. Initializes the vma with a fault handler
Jes Sorensen17a3b052006-09-27 01:50:11 -0700251 * and private data structure necessary to allocate, track, and free the
252 * underlying pages.
253 */
254static int
Cliff Wickman4191ba22007-09-18 22:46:31 -0700255mspec_mmap(struct file *file, struct vm_area_struct *vma,
256 enum mspec_page_type type)
Jes Sorensen17a3b052006-09-27 01:50:11 -0700257{
258 struct vma_data *vdata;
Cliff Wickman4191ba22007-09-18 22:46:31 -0700259 int pages, vdata_size, flags = 0;
Jes Sorensen17a3b052006-09-27 01:50:11 -0700260
261 if (vma->vm_pgoff != 0)
262 return -EINVAL;
263
264 if ((vma->vm_flags & VM_SHARED) == 0)
265 return -EINVAL;
266
267 if ((vma->vm_flags & VM_WRITE) == 0)
268 return -EPERM;
269
270 pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
271 vdata_size = sizeof(struct vma_data) + pages * sizeof(long);
272 if (vdata_size <= PAGE_SIZE)
Rakib Mullick658c74c2011-05-26 16:25:56 -0700273 vdata = kzalloc(vdata_size, GFP_KERNEL);
Cliff Wickman4191ba22007-09-18 22:46:31 -0700274 else {
Rakib Mullick658c74c2011-05-26 16:25:56 -0700275 vdata = vzalloc(vdata_size);
Cliff Wickman4191ba22007-09-18 22:46:31 -0700276 flags = VMD_VMALLOCED;
277 }
Jes Sorensen17a3b052006-09-27 01:50:11 -0700278 if (!vdata)
279 return -ENOMEM;
Jes Sorensen17a3b052006-09-27 01:50:11 -0700280
Cliff Wickman4191ba22007-09-18 22:46:31 -0700281 vdata->vm_start = vma->vm_start;
282 vdata->vm_end = vma->vm_end;
283 vdata->flags = flags;
Jes Sorensen17a3b052006-09-27 01:50:11 -0700284 vdata->type = type;
285 spin_lock_init(&vdata->lock);
Tony Lucka1193652012-07-26 10:55:26 -0700286 atomic_set(&vdata->refcnt, 1);
Jes Sorensen17a3b052006-09-27 01:50:11 -0700287 vma->vm_private_data = vdata;
288
Konstantin Khlebnikov314e51b2012-10-08 16:29:02 -0700289 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
Jes Sorensen17a3b052006-09-27 01:50:11 -0700290 if (vdata->type == MSPEC_FETCHOP || vdata->type == MSPEC_UNCACHED)
291 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
292 vma->vm_ops = &mspec_vm_ops;
293
294 return 0;
295}
296
297static int
298fetchop_mmap(struct file *file, struct vm_area_struct *vma)
299{
300 return mspec_mmap(file, vma, MSPEC_FETCHOP);
301}
302
303static int
304cached_mmap(struct file *file, struct vm_area_struct *vma)
305{
306 return mspec_mmap(file, vma, MSPEC_CACHED);
307}
308
309static int
310uncached_mmap(struct file *file, struct vm_area_struct *vma)
311{
312 return mspec_mmap(file, vma, MSPEC_UNCACHED);
313}
314
Arjan van de Ven2b8693c2007-02-12 00:55:32 -0800315static const struct file_operations fetchop_fops = {
Jes Sorensen17a3b052006-09-27 01:50:11 -0700316 .owner = THIS_MODULE,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200317 .mmap = fetchop_mmap,
318 .llseek = noop_llseek,
Jes Sorensen17a3b052006-09-27 01:50:11 -0700319};
320
321static struct miscdevice fetchop_miscdev = {
322 .minor = MISC_DYNAMIC_MINOR,
323 .name = "sgi_fetchop",
324 .fops = &fetchop_fops
325};
326
Arjan van de Ven2b8693c2007-02-12 00:55:32 -0800327static const struct file_operations cached_fops = {
Jes Sorensen17a3b052006-09-27 01:50:11 -0700328 .owner = THIS_MODULE,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200329 .mmap = cached_mmap,
330 .llseek = noop_llseek,
Jes Sorensen17a3b052006-09-27 01:50:11 -0700331};
332
333static struct miscdevice cached_miscdev = {
334 .minor = MISC_DYNAMIC_MINOR,
335 .name = "mspec_cached",
336 .fops = &cached_fops
337};
338
Arjan van de Ven2b8693c2007-02-12 00:55:32 -0800339static const struct file_operations uncached_fops = {
Jes Sorensen17a3b052006-09-27 01:50:11 -0700340 .owner = THIS_MODULE,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200341 .mmap = uncached_mmap,
342 .llseek = noop_llseek,
Jes Sorensen17a3b052006-09-27 01:50:11 -0700343};
344
345static struct miscdevice uncached_miscdev = {
346 .minor = MISC_DYNAMIC_MINOR,
347 .name = "mspec_uncached",
348 .fops = &uncached_fops
349};
350
351/*
352 * mspec_init
353 *
354 * Called at boot time to initialize the mspec facility.
355 */
356static int __init
357mspec_init(void)
358{
359 int ret;
360 int nid;
361
362 /*
363 * The fetchop device only works on SN2 hardware, uncached and cached
364 * memory drivers should both be valid on all ia64 hardware
365 */
Jes Sorensen1a4b0fc2006-11-10 12:27:49 -0800366#ifdef CONFIG_SGI_SN
Jes Sorensen17a3b052006-09-27 01:50:11 -0700367 if (ia64_platform_is("sn2")) {
368 is_sn2 = 1;
369 if (is_shub2()) {
370 ret = -ENOMEM;
Christoph Lameter2dca53a2007-10-16 01:25:33 -0700371 for_each_node_state(nid, N_ONLINE) {
Jes Sorensen17a3b052006-09-27 01:50:11 -0700372 int actual_nid;
373 int nasid;
374 unsigned long phys;
375
Dean Nelsone4a064d2008-04-25 15:22:19 -0500376 scratch_page[nid] = uncached_alloc_page(nid, 1);
Jes Sorensen17a3b052006-09-27 01:50:11 -0700377 if (scratch_page[nid] == 0)
378 goto free_scratch_pages;
379 phys = __pa(scratch_page[nid]);
380 nasid = get_node_number(phys);
381 actual_nid = nasid_to_cnodeid(nasid);
382 if (actual_nid != nid)
383 goto free_scratch_pages;
384 }
385 }
386
387 ret = misc_register(&fetchop_miscdev);
388 if (ret) {
389 printk(KERN_ERR
390 "%s: failed to register device %i\n",
391 FETCHOP_ID, ret);
392 goto free_scratch_pages;
393 }
394 }
Jes Sorensen1a4b0fc2006-11-10 12:27:49 -0800395#endif
Jes Sorensen17a3b052006-09-27 01:50:11 -0700396 ret = misc_register(&cached_miscdev);
397 if (ret) {
398 printk(KERN_ERR "%s: failed to register device %i\n",
399 CACHED_ID, ret);
400 if (is_sn2)
401 misc_deregister(&fetchop_miscdev);
402 goto free_scratch_pages;
403 }
404 ret = misc_register(&uncached_miscdev);
405 if (ret) {
406 printk(KERN_ERR "%s: failed to register device %i\n",
407 UNCACHED_ID, ret);
408 misc_deregister(&cached_miscdev);
409 if (is_sn2)
410 misc_deregister(&fetchop_miscdev);
411 goto free_scratch_pages;
412 }
413
414 printk(KERN_INFO "%s %s initialized devices: %s %s %s\n",
415 MSPEC_BASENAME, REVISION, is_sn2 ? FETCHOP_ID : "",
416 CACHED_ID, UNCACHED_ID);
417
418 return 0;
419
420 free_scratch_pages:
421 for_each_node(nid) {
422 if (scratch_page[nid] != 0)
Dean Nelsone4a064d2008-04-25 15:22:19 -0500423 uncached_free_page(scratch_page[nid], 1);
Jes Sorensen17a3b052006-09-27 01:50:11 -0700424 }
425 return ret;
426}
427
428static void __exit
429mspec_exit(void)
430{
431 int nid;
432
433 misc_deregister(&uncached_miscdev);
434 misc_deregister(&cached_miscdev);
435 if (is_sn2) {
436 misc_deregister(&fetchop_miscdev);
437
438 for_each_node(nid) {
439 if (scratch_page[nid] != 0)
Dean Nelsone4a064d2008-04-25 15:22:19 -0500440 uncached_free_page(scratch_page[nid], 1);
Jes Sorensen17a3b052006-09-27 01:50:11 -0700441 }
442 }
443}
444
445module_init(mspec_init);
446module_exit(mspec_exit);
447
448MODULE_AUTHOR("Silicon Graphics, Inc. <linux-altix@sgi.com>");
449MODULE_DESCRIPTION("Driver for SGI SN special memory operations");
450MODULE_LICENSE("GPL");