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/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 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 */ 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 218 paddr = maddr & ~__IA64_UNCACHED_OFFSET; 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 } 293 294 static const struct file_operations fetchop_fops = { 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 }; 304 305 static const struct file_operations cached_fops = { 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 }; 315 316 static const struct file_operations uncached_fops = { 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 */ 342 #ifdef CONFIG_SGI_SN 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 } 371 #endif 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"); 427