2 * Copyright (C) 2001-2006 Silicon Graphics, Inc. All rights
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.
11 * SN Platform Special Memory (mspec) Support
13 * This driver exports the SN special memory (mspec) facility to user
15 * There are three types of memory made available thru this driver:
16 * fetchops, uncached and cached.
18 * Fetchops are atomic memory operations that are implemented in the
19 * memory controller on SGI SN hardware.
21 * Uncached are used for memory write combining feature of the ia64
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.
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>
42 #include <linux/vmalloc.h>
43 #include <linux/string.h>
44 #include <linux/slab.h>
45 #include <linux/numa.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>
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"
68 * Page types allocated by the device.
70 enum mspec_page_type {
83 * One of these structures is allocated when an mspec region is mmaped. The
84 * structure is pointed to by the vma->vm_private_data field in the vma struct.
85 * This structure is used to record the addresses of the mspec pages.
86 * This structure is shared by all vma's that are split off from the
87 * original vma when split_vma()'s are done.
89 * The refcnt is incremented atomically because mm->mmap_sem does not
90 * protect in fork case where multiple tasks share the vma_data.
93 atomic_t refcnt; /* Number of vmas sharing the data. */
94 spinlock_t lock; /* Serialize access to this structure. */
95 int count; /* Number of pages allocated. */
96 enum mspec_page_type type; /* Type of pages allocated. */
97 int flags; /* See VMD_xxx below. */
98 unsigned long vm_start; /* Original (unsplit) base. */
99 unsigned long vm_end; /* Original (unsplit) end. */
100 unsigned long maddr[0]; /* Array of MSPEC addresses. */
103 #define VMD_VMALLOCED 0x1 /* vmalloc'd rather than kmalloc'd */
105 /* used on shub2 to clear FOP cache in the HUB */
106 static unsigned long scratch_page[MAX_NUMNODES];
107 #define SH2_AMO_CACHE_ENTRIES 4
110 mspec_zero_block(unsigned long addr, int len)
120 nid = nasid_to_cnodeid(get_node_number(__pa(addr)));
121 p = (void *)TO_AMO(scratch_page[nid]);
123 for (i=0; i < SH2_AMO_CACHE_ENTRIES; i++) {
124 FETCHOP_LOAD_OP(p, FETCHOP_LOAD);
125 p += FETCHOP_VAR_SIZE;
129 status = bte_copy(0, addr & ~__IA64_UNCACHED_OFFSET, len,
130 BTE_WACQUIRE | BTE_ZERO_FILL, NULL);
132 memset((char *) addr, 0, len);
141 * Called when a device mapping is created by a means other than mmap
142 * (via fork, munmap, etc.). Increments the reference count on the
143 * underlying mspec data so it is not freed prematurely.
146 mspec_open(struct vm_area_struct *vma)
148 struct vma_data *vdata;
150 vdata = vma->vm_private_data;
151 atomic_inc(&vdata->refcnt);
157 * Called when unmapping a device mapping. Frees all mspec pages
158 * belonging to the vma.
161 mspec_close(struct vm_area_struct *vma)
163 struct vma_data *vdata;
164 int index, last_index, result;
165 unsigned long my_page;
167 vdata = vma->vm_private_data;
169 BUG_ON(vma->vm_start < vdata->vm_start || vma->vm_end > vdata->vm_end);
171 spin_lock(&vdata->lock);
172 index = (vma->vm_start - vdata->vm_start) >> PAGE_SHIFT;
173 last_index = (vma->vm_end - vdata->vm_start) >> PAGE_SHIFT;
174 for (; index < last_index; index++) {
175 if (vdata->maddr[index] == 0)
178 * Clear the page before sticking it back
181 my_page = vdata->maddr[index];
182 vdata->maddr[index] = 0;
183 spin_unlock(&vdata->lock);
184 result = mspec_zero_block(my_page, PAGE_SIZE);
186 uncached_free_page(my_page);
188 printk(KERN_WARNING "mspec_close(): "
189 "failed to zero page %i\n",
191 spin_lock(&vdata->lock);
193 spin_unlock(&vdata->lock);
195 if (!atomic_dec_and_test(&vdata->refcnt))
198 if (vdata->flags & VMD_VMALLOCED)
208 * Creates a mspec page and maps it to user space.
211 mspec_nopfn(struct vm_area_struct *vma, unsigned long address)
213 unsigned long paddr, maddr;
216 struct vma_data *vdata = vma->vm_private_data;
218 BUG_ON(address < vdata->vm_start || address >= vdata->vm_end);
219 index = (address - vdata->vm_start) >> PAGE_SHIFT;
220 maddr = (volatile unsigned long) vdata->maddr[index];
222 maddr = uncached_alloc_page(numa_node_id());
226 spin_lock(&vdata->lock);
227 if (vdata->maddr[index] == 0) {
229 vdata->maddr[index] = maddr;
231 uncached_free_page(maddr);
232 maddr = vdata->maddr[index];
234 spin_unlock(&vdata->lock);
237 if (vdata->type == MSPEC_FETCHOP)
238 paddr = TO_AMO(maddr);
240 paddr = maddr & ~__IA64_UNCACHED_OFFSET;
242 pfn = paddr >> PAGE_SHIFT;
247 static struct vm_operations_struct mspec_vm_ops = {
249 .close = mspec_close,
256 * Called when mmaping the device. Initializes the vma with a fault handler
257 * and private data structure necessary to allocate, track, and free the
261 mspec_mmap(struct file *file, struct vm_area_struct *vma,
262 enum mspec_page_type type)
264 struct vma_data *vdata;
265 int pages, vdata_size, flags = 0;
267 if (vma->vm_pgoff != 0)
270 if ((vma->vm_flags & VM_SHARED) == 0)
273 if ((vma->vm_flags & VM_WRITE) == 0)
276 pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
277 vdata_size = sizeof(struct vma_data) + pages * sizeof(long);
278 if (vdata_size <= PAGE_SIZE)
279 vdata = kmalloc(vdata_size, GFP_KERNEL);
281 vdata = vmalloc(vdata_size);
282 flags = VMD_VMALLOCED;
286 memset(vdata, 0, vdata_size);
288 vdata->vm_start = vma->vm_start;
289 vdata->vm_end = vma->vm_end;
290 vdata->flags = flags;
292 spin_lock_init(&vdata->lock);
293 vdata->refcnt = ATOMIC_INIT(1);
294 vma->vm_private_data = vdata;
296 vma->vm_flags |= (VM_IO | VM_RESERVED | VM_PFNMAP);
297 if (vdata->type == MSPEC_FETCHOP || vdata->type == MSPEC_UNCACHED)
298 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
299 vma->vm_ops = &mspec_vm_ops;
305 fetchop_mmap(struct file *file, struct vm_area_struct *vma)
307 return mspec_mmap(file, vma, MSPEC_FETCHOP);
311 cached_mmap(struct file *file, struct vm_area_struct *vma)
313 return mspec_mmap(file, vma, MSPEC_CACHED);
317 uncached_mmap(struct file *file, struct vm_area_struct *vma)
319 return mspec_mmap(file, vma, MSPEC_UNCACHED);
322 static const struct file_operations fetchop_fops = {
323 .owner = THIS_MODULE,
327 static struct miscdevice fetchop_miscdev = {
328 .minor = MISC_DYNAMIC_MINOR,
329 .name = "sgi_fetchop",
330 .fops = &fetchop_fops
333 static const struct file_operations cached_fops = {
334 .owner = THIS_MODULE,
338 static struct miscdevice cached_miscdev = {
339 .minor = MISC_DYNAMIC_MINOR,
340 .name = "mspec_cached",
344 static const struct file_operations uncached_fops = {
345 .owner = THIS_MODULE,
346 .mmap = uncached_mmap
349 static struct miscdevice uncached_miscdev = {
350 .minor = MISC_DYNAMIC_MINOR,
351 .name = "mspec_uncached",
352 .fops = &uncached_fops
358 * Called at boot time to initialize the mspec facility.
367 * The fetchop device only works on SN2 hardware, uncached and cached
368 * memory drivers should both be valid on all ia64 hardware
371 if (ia64_platform_is("sn2")) {
375 for_each_online_node(nid) {
380 scratch_page[nid] = uncached_alloc_page(nid);
381 if (scratch_page[nid] == 0)
382 goto free_scratch_pages;
383 phys = __pa(scratch_page[nid]);
384 nasid = get_node_number(phys);
385 actual_nid = nasid_to_cnodeid(nasid);
386 if (actual_nid != nid)
387 goto free_scratch_pages;
391 ret = misc_register(&fetchop_miscdev);
394 "%s: failed to register device %i\n",
396 goto free_scratch_pages;
400 ret = misc_register(&cached_miscdev);
402 printk(KERN_ERR "%s: failed to register device %i\n",
405 misc_deregister(&fetchop_miscdev);
406 goto free_scratch_pages;
408 ret = misc_register(&uncached_miscdev);
410 printk(KERN_ERR "%s: failed to register device %i\n",
412 misc_deregister(&cached_miscdev);
414 misc_deregister(&fetchop_miscdev);
415 goto free_scratch_pages;
418 printk(KERN_INFO "%s %s initialized devices: %s %s %s\n",
419 MSPEC_BASENAME, REVISION, is_sn2 ? FETCHOP_ID : "",
420 CACHED_ID, UNCACHED_ID);
426 if (scratch_page[nid] != 0)
427 uncached_free_page(scratch_page[nid]);
437 misc_deregister(&uncached_miscdev);
438 misc_deregister(&cached_miscdev);
440 misc_deregister(&fetchop_miscdev);
443 if (scratch_page[nid] != 0)
444 uncached_free_page(scratch_page[nid]);
449 module_init(mspec_init);
450 module_exit(mspec_exit);
452 MODULE_AUTHOR("Silicon Graphics, Inc. <linux-altix@sgi.com>");
453 MODULE_DESCRIPTION("Driver for SGI SN special memory operations");
454 MODULE_LICENSE("GPL");