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/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 #ifdef CONFIG_SGI_SN 77 static int is_sn2; 78 #else 79 #define is_sn2 0 80 #endif 81 82 /* 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 */ 87 struct vma_data { 88 atomic_t refcnt; /* Number of vmas sharing the data. */ 89 spinlock_t lock; /* Serialize access to the vma. */ 90 int count; /* Number of pages allocated. */ 91 int type; /* Type of pages allocated. */ 92 unsigned long maddr[0]; /* Array of MSPEC addresses. */ 93 }; 94 95 /* used on shub2 to clear FOP cache in the HUB */ 96 static unsigned long scratch_page[MAX_NUMNODES]; 97 #define SH2_AMO_CACHE_ENTRIES 4 98 99 static inline int 100 mspec_zero_block(unsigned long addr, int len) 101 { 102 int status; 103 104 if (is_sn2) { 105 if (is_shub2()) { 106 int nid; 107 void *p; 108 int i; 109 110 nid = nasid_to_cnodeid(get_node_number(__pa(addr))); 111 p = (void *)TO_AMO(scratch_page[nid]); 112 113 for (i=0; i < SH2_AMO_CACHE_ENTRIES; i++) { 114 FETCHOP_LOAD_OP(p, FETCHOP_LOAD); 115 p += FETCHOP_VAR_SIZE; 116 } 117 } 118 119 status = bte_copy(0, addr & ~__IA64_UNCACHED_OFFSET, len, 120 BTE_WACQUIRE | BTE_ZERO_FILL, NULL); 121 } else { 122 memset((char *) addr, 0, len); 123 status = 0; 124 } 125 return status; 126 } 127 128 /* 129 * mspec_open 130 * 131 * Called when a device mapping is created by a means other than mmap 132 * (via fork, etc.). Increments the reference count on the underlying 133 * mspec data so it is not freed prematurely. 134 */ 135 static void 136 mspec_open(struct vm_area_struct *vma) 137 { 138 struct vma_data *vdata; 139 140 vdata = vma->vm_private_data; 141 atomic_inc(&vdata->refcnt); 142 } 143 144 /* 145 * mspec_close 146 * 147 * Called when unmapping a device mapping. Frees all mspec pages 148 * belonging to the vma. 149 */ 150 static void 151 mspec_close(struct vm_area_struct *vma) 152 { 153 struct vma_data *vdata; 154 int i, pages, result, vdata_size; 155 156 vdata = vma->vm_private_data; 157 if (!atomic_dec_and_test(&vdata->refcnt)) 158 return; 159 160 pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; 161 vdata_size = sizeof(struct vma_data) + pages * sizeof(long); 162 for (i = 0; i < pages; i++) { 163 if (vdata->maddr[i] == 0) 164 continue; 165 /* 166 * Clear the page before sticking it back 167 * into the pool. 168 */ 169 result = mspec_zero_block(vdata->maddr[i], PAGE_SIZE); 170 if (!result) 171 uncached_free_page(vdata->maddr[i]); 172 else 173 printk(KERN_WARNING "mspec_close(): " 174 "failed to zero page %i\n", 175 result); 176 } 177 178 if (vdata_size <= PAGE_SIZE) 179 kfree(vdata); 180 else 181 vfree(vdata); 182 } 183 184 185 /* 186 * mspec_nopfn 187 * 188 * Creates a mspec page and maps it to user space. 189 */ 190 static unsigned long 191 mspec_nopfn(struct vm_area_struct *vma, unsigned long address) 192 { 193 unsigned long paddr, maddr; 194 unsigned long pfn; 195 int index; 196 struct vma_data *vdata = vma->vm_private_data; 197 198 index = (address - vma->vm_start) >> PAGE_SHIFT; 199 maddr = (volatile unsigned long) vdata->maddr[index]; 200 if (maddr == 0) { 201 maddr = uncached_alloc_page(numa_node_id()); 202 if (maddr == 0) 203 return NOPFN_OOM; 204 205 spin_lock(&vdata->lock); 206 if (vdata->maddr[index] == 0) { 207 vdata->count++; 208 vdata->maddr[index] = maddr; 209 } else { 210 uncached_free_page(maddr); 211 maddr = vdata->maddr[index]; 212 } 213 spin_unlock(&vdata->lock); 214 } 215 216 if (vdata->type == MSPEC_FETCHOP) 217 paddr = TO_AMO(maddr); 218 else 219 paddr = maddr & ~__IA64_UNCACHED_OFFSET; 220 221 pfn = paddr >> PAGE_SHIFT; 222 223 return pfn; 224 } 225 226 static struct vm_operations_struct mspec_vm_ops = { 227 .open = mspec_open, 228 .close = mspec_close, 229 .nopfn = mspec_nopfn 230 }; 231 232 /* 233 * mspec_mmap 234 * 235 * Called when mmaping the device. Initializes the vma with a fault handler 236 * and private data structure necessary to allocate, track, and free the 237 * underlying pages. 238 */ 239 static int 240 mspec_mmap(struct file *file, struct vm_area_struct *vma, int type) 241 { 242 struct vma_data *vdata; 243 int pages, vdata_size; 244 245 if (vma->vm_pgoff != 0) 246 return -EINVAL; 247 248 if ((vma->vm_flags & VM_SHARED) == 0) 249 return -EINVAL; 250 251 if ((vma->vm_flags & VM_WRITE) == 0) 252 return -EPERM; 253 254 pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; 255 vdata_size = sizeof(struct vma_data) + pages * sizeof(long); 256 if (vdata_size <= PAGE_SIZE) 257 vdata = kmalloc(vdata_size, GFP_KERNEL); 258 else 259 vdata = vmalloc(vdata_size); 260 if (!vdata) 261 return -ENOMEM; 262 memset(vdata, 0, vdata_size); 263 264 vdata->type = type; 265 spin_lock_init(&vdata->lock); 266 vdata->refcnt = ATOMIC_INIT(1); 267 vma->vm_private_data = vdata; 268 269 vma->vm_flags |= (VM_IO | VM_RESERVED | VM_PFNMAP); 270 if (vdata->type == MSPEC_FETCHOP || vdata->type == MSPEC_UNCACHED) 271 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); 272 vma->vm_ops = &mspec_vm_ops; 273 274 return 0; 275 } 276 277 static int 278 fetchop_mmap(struct file *file, struct vm_area_struct *vma) 279 { 280 return mspec_mmap(file, vma, MSPEC_FETCHOP); 281 } 282 283 static int 284 cached_mmap(struct file *file, struct vm_area_struct *vma) 285 { 286 return mspec_mmap(file, vma, MSPEC_CACHED); 287 } 288 289 static int 290 uncached_mmap(struct file *file, struct vm_area_struct *vma) 291 { 292 return mspec_mmap(file, vma, MSPEC_UNCACHED); 293 } 294 295 static const struct file_operations fetchop_fops = { 296 .owner = THIS_MODULE, 297 .mmap = fetchop_mmap 298 }; 299 300 static struct miscdevice fetchop_miscdev = { 301 .minor = MISC_DYNAMIC_MINOR, 302 .name = "sgi_fetchop", 303 .fops = &fetchop_fops 304 }; 305 306 static const struct file_operations cached_fops = { 307 .owner = THIS_MODULE, 308 .mmap = cached_mmap 309 }; 310 311 static struct miscdevice cached_miscdev = { 312 .minor = MISC_DYNAMIC_MINOR, 313 .name = "mspec_cached", 314 .fops = &cached_fops 315 }; 316 317 static const struct file_operations uncached_fops = { 318 .owner = THIS_MODULE, 319 .mmap = uncached_mmap 320 }; 321 322 static struct miscdevice uncached_miscdev = { 323 .minor = MISC_DYNAMIC_MINOR, 324 .name = "mspec_uncached", 325 .fops = &uncached_fops 326 }; 327 328 /* 329 * mspec_init 330 * 331 * Called at boot time to initialize the mspec facility. 332 */ 333 static int __init 334 mspec_init(void) 335 { 336 int ret; 337 int nid; 338 339 /* 340 * The fetchop device only works on SN2 hardware, uncached and cached 341 * memory drivers should both be valid on all ia64 hardware 342 */ 343 #ifdef CONFIG_SGI_SN 344 if (ia64_platform_is("sn2")) { 345 is_sn2 = 1; 346 if (is_shub2()) { 347 ret = -ENOMEM; 348 for_each_online_node(nid) { 349 int actual_nid; 350 int nasid; 351 unsigned long phys; 352 353 scratch_page[nid] = uncached_alloc_page(nid); 354 if (scratch_page[nid] == 0) 355 goto free_scratch_pages; 356 phys = __pa(scratch_page[nid]); 357 nasid = get_node_number(phys); 358 actual_nid = nasid_to_cnodeid(nasid); 359 if (actual_nid != nid) 360 goto free_scratch_pages; 361 } 362 } 363 364 ret = misc_register(&fetchop_miscdev); 365 if (ret) { 366 printk(KERN_ERR 367 "%s: failed to register device %i\n", 368 FETCHOP_ID, ret); 369 goto free_scratch_pages; 370 } 371 } 372 #endif 373 ret = misc_register(&cached_miscdev); 374 if (ret) { 375 printk(KERN_ERR "%s: failed to register device %i\n", 376 CACHED_ID, ret); 377 if (is_sn2) 378 misc_deregister(&fetchop_miscdev); 379 goto free_scratch_pages; 380 } 381 ret = misc_register(&uncached_miscdev); 382 if (ret) { 383 printk(KERN_ERR "%s: failed to register device %i\n", 384 UNCACHED_ID, ret); 385 misc_deregister(&cached_miscdev); 386 if (is_sn2) 387 misc_deregister(&fetchop_miscdev); 388 goto free_scratch_pages; 389 } 390 391 printk(KERN_INFO "%s %s initialized devices: %s %s %s\n", 392 MSPEC_BASENAME, REVISION, is_sn2 ? FETCHOP_ID : "", 393 CACHED_ID, UNCACHED_ID); 394 395 return 0; 396 397 free_scratch_pages: 398 for_each_node(nid) { 399 if (scratch_page[nid] != 0) 400 uncached_free_page(scratch_page[nid]); 401 } 402 return ret; 403 } 404 405 static void __exit 406 mspec_exit(void) 407 { 408 int nid; 409 410 misc_deregister(&uncached_miscdev); 411 misc_deregister(&cached_miscdev); 412 if (is_sn2) { 413 misc_deregister(&fetchop_miscdev); 414 415 for_each_node(nid) { 416 if (scratch_page[nid] != 0) 417 uncached_free_page(scratch_page[nid]); 418 } 419 } 420 } 421 422 module_init(mspec_init); 423 module_exit(mspec_exit); 424 425 MODULE_AUTHOR("Silicon Graphics, Inc. <linux-altix@sgi.com>"); 426 MODULE_DESCRIPTION("Driver for SGI SN special memory operations"); 427 MODULE_LICENSE("GPL"); 428