1 /* 2 * Copyright 2014 IBM Corp. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 7 * 2 of the License, or (at your option) any later version. 8 */ 9 10 #include <linux/module.h> 11 #include <linux/kernel.h> 12 #include <linux/bitmap.h> 13 #include <linux/sched.h> 14 #include <linux/pid.h> 15 #include <linux/fs.h> 16 #include <linux/mm.h> 17 #include <linux/debugfs.h> 18 #include <linux/slab.h> 19 #include <linux/idr.h> 20 #include <linux/sched/mm.h> 21 #include <linux/mmu_context.h> 22 #include <asm/cputable.h> 23 #include <asm/current.h> 24 #include <asm/copro.h> 25 26 #include "cxl.h" 27 28 /* 29 * Allocates space for a CXL context. 30 */ 31 struct cxl_context *cxl_context_alloc(void) 32 { 33 return kzalloc(sizeof(struct cxl_context), GFP_KERNEL); 34 } 35 36 /* 37 * Initialises a CXL context. 38 */ 39 int cxl_context_init(struct cxl_context *ctx, struct cxl_afu *afu, bool master) 40 { 41 int i; 42 43 ctx->afu = afu; 44 ctx->master = master; 45 ctx->pid = NULL; /* Set in start work ioctl */ 46 mutex_init(&ctx->mapping_lock); 47 ctx->mapping = NULL; 48 ctx->tidr = 0; 49 ctx->assign_tidr = false; 50 51 if (cxl_is_power8()) { 52 spin_lock_init(&ctx->sste_lock); 53 54 /* 55 * Allocate the segment table before we put it in the IDR so that we 56 * can always access it when dereferenced from IDR. For the same 57 * reason, the segment table is only destroyed after the context is 58 * removed from the IDR. Access to this in the IOCTL is protected by 59 * Linux filesytem symantics (can't IOCTL until open is complete). 60 */ 61 i = cxl_alloc_sst(ctx); 62 if (i) 63 return i; 64 } 65 66 INIT_WORK(&ctx->fault_work, cxl_handle_fault); 67 68 init_waitqueue_head(&ctx->wq); 69 spin_lock_init(&ctx->lock); 70 71 ctx->irq_bitmap = NULL; 72 ctx->pending_irq = false; 73 ctx->pending_fault = false; 74 ctx->pending_afu_err = false; 75 76 INIT_LIST_HEAD(&ctx->irq_names); 77 78 /* 79 * When we have to destroy all contexts in cxl_context_detach_all() we 80 * end up with afu_release_irqs() called from inside a 81 * idr_for_each_entry(). Hence we need to make sure that anything 82 * dereferenced from this IDR is ok before we allocate the IDR here. 83 * This clears out the IRQ ranges to ensure this. 84 */ 85 for (i = 0; i < CXL_IRQ_RANGES; i++) 86 ctx->irqs.range[i] = 0; 87 88 mutex_init(&ctx->status_mutex); 89 90 ctx->status = OPENED; 91 92 /* 93 * Allocating IDR! We better make sure everything's setup that 94 * dereferences from it. 95 */ 96 mutex_lock(&afu->contexts_lock); 97 idr_preload(GFP_KERNEL); 98 i = idr_alloc(&ctx->afu->contexts_idr, ctx, 0, 99 ctx->afu->num_procs, GFP_NOWAIT); 100 idr_preload_end(); 101 mutex_unlock(&afu->contexts_lock); 102 if (i < 0) 103 return i; 104 105 ctx->pe = i; 106 if (cpu_has_feature(CPU_FTR_HVMODE)) { 107 ctx->elem = &ctx->afu->native->spa[i]; 108 ctx->external_pe = ctx->pe; 109 } else { 110 ctx->external_pe = -1; /* assigned when attaching */ 111 } 112 ctx->pe_inserted = false; 113 114 /* 115 * take a ref on the afu so that it stays alive at-least till 116 * this context is reclaimed inside reclaim_ctx. 117 */ 118 cxl_afu_get(afu); 119 return 0; 120 } 121 122 void cxl_context_set_mapping(struct cxl_context *ctx, 123 struct address_space *mapping) 124 { 125 mutex_lock(&ctx->mapping_lock); 126 ctx->mapping = mapping; 127 mutex_unlock(&ctx->mapping_lock); 128 } 129 130 static vm_fault_t cxl_mmap_fault(struct vm_fault *vmf) 131 { 132 struct vm_area_struct *vma = vmf->vma; 133 struct cxl_context *ctx = vma->vm_file->private_data; 134 u64 area, offset; 135 vm_fault_t ret; 136 137 offset = vmf->pgoff << PAGE_SHIFT; 138 139 pr_devel("%s: pe: %i address: 0x%lx offset: 0x%llx\n", 140 __func__, ctx->pe, vmf->address, offset); 141 142 if (ctx->afu->current_mode == CXL_MODE_DEDICATED) { 143 area = ctx->afu->psn_phys; 144 if (offset >= ctx->afu->adapter->ps_size) 145 return VM_FAULT_SIGBUS; 146 } else { 147 area = ctx->psn_phys; 148 if (offset >= ctx->psn_size) 149 return VM_FAULT_SIGBUS; 150 } 151 152 mutex_lock(&ctx->status_mutex); 153 154 if (ctx->status != STARTED) { 155 mutex_unlock(&ctx->status_mutex); 156 pr_devel("%s: Context not started, failing problem state access\n", __func__); 157 if (ctx->mmio_err_ff) { 158 if (!ctx->ff_page) { 159 ctx->ff_page = alloc_page(GFP_USER); 160 if (!ctx->ff_page) 161 return VM_FAULT_OOM; 162 memset(page_address(ctx->ff_page), 0xff, PAGE_SIZE); 163 } 164 get_page(ctx->ff_page); 165 vmf->page = ctx->ff_page; 166 vma->vm_page_prot = pgprot_cached(vma->vm_page_prot); 167 return 0; 168 } 169 return VM_FAULT_SIGBUS; 170 } 171 172 ret = vmf_insert_pfn(vma, vmf->address, (area + offset) >> PAGE_SHIFT); 173 174 mutex_unlock(&ctx->status_mutex); 175 176 return ret; 177 } 178 179 static const struct vm_operations_struct cxl_mmap_vmops = { 180 .fault = cxl_mmap_fault, 181 }; 182 183 /* 184 * Map a per-context mmio space into the given vma. 185 */ 186 int cxl_context_iomap(struct cxl_context *ctx, struct vm_area_struct *vma) 187 { 188 u64 start = vma->vm_pgoff << PAGE_SHIFT; 189 u64 len = vma->vm_end - vma->vm_start; 190 191 if (ctx->afu->current_mode == CXL_MODE_DEDICATED) { 192 if (start + len > ctx->afu->adapter->ps_size) 193 return -EINVAL; 194 195 if (cxl_is_power9()) { 196 /* 197 * Make sure there is a valid problem state 198 * area space for this AFU. 199 */ 200 if (ctx->master && !ctx->afu->psa) { 201 pr_devel("AFU doesn't support mmio space\n"); 202 return -EINVAL; 203 } 204 205 /* Can't mmap until the AFU is enabled */ 206 if (!ctx->afu->enabled) 207 return -EBUSY; 208 } 209 } else { 210 if (start + len > ctx->psn_size) 211 return -EINVAL; 212 213 /* Make sure there is a valid per process space for this AFU */ 214 if ((ctx->master && !ctx->afu->psa) || (!ctx->afu->pp_psa)) { 215 pr_devel("AFU doesn't support mmio space\n"); 216 return -EINVAL; 217 } 218 219 /* Can't mmap until the AFU is enabled */ 220 if (!ctx->afu->enabled) 221 return -EBUSY; 222 } 223 224 pr_devel("%s: mmio physical: %llx pe: %i master:%i\n", __func__, 225 ctx->psn_phys, ctx->pe , ctx->master); 226 227 vma->vm_flags |= VM_IO | VM_PFNMAP; 228 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); 229 vma->vm_ops = &cxl_mmap_vmops; 230 return 0; 231 } 232 233 /* 234 * Detach a context from the hardware. This disables interrupts and doesn't 235 * return until all outstanding interrupts for this context have completed. The 236 * hardware should no longer access *ctx after this has returned. 237 */ 238 int __detach_context(struct cxl_context *ctx) 239 { 240 enum cxl_context_status status; 241 242 mutex_lock(&ctx->status_mutex); 243 status = ctx->status; 244 ctx->status = CLOSED; 245 mutex_unlock(&ctx->status_mutex); 246 if (status != STARTED) 247 return -EBUSY; 248 249 /* Only warn if we detached while the link was OK. 250 * If detach fails when hw is down, we don't care. 251 */ 252 WARN_ON(cxl_ops->detach_process(ctx) && 253 cxl_ops->link_ok(ctx->afu->adapter, ctx->afu)); 254 flush_work(&ctx->fault_work); /* Only needed for dedicated process */ 255 256 /* 257 * Wait until no further interrupts are presented by the PSL 258 * for this context. 259 */ 260 if (cxl_ops->irq_wait) 261 cxl_ops->irq_wait(ctx); 262 263 /* release the reference to the group leader and mm handling pid */ 264 put_pid(ctx->pid); 265 266 cxl_ctx_put(); 267 268 /* Decrease the attached context count on the adapter */ 269 cxl_adapter_context_put(ctx->afu->adapter); 270 271 /* Decrease the mm count on the context */ 272 cxl_context_mm_count_put(ctx); 273 if (ctx->mm) 274 mm_context_remove_copro(ctx->mm); 275 ctx->mm = NULL; 276 277 return 0; 278 } 279 280 /* 281 * Detach the given context from the AFU. This doesn't actually 282 * free the context but it should stop the context running in hardware 283 * (ie. prevent this context from generating any further interrupts 284 * so that it can be freed). 285 */ 286 void cxl_context_detach(struct cxl_context *ctx) 287 { 288 int rc; 289 290 rc = __detach_context(ctx); 291 if (rc) 292 return; 293 294 afu_release_irqs(ctx, ctx); 295 wake_up_all(&ctx->wq); 296 } 297 298 /* 299 * Detach all contexts on the given AFU. 300 */ 301 void cxl_context_detach_all(struct cxl_afu *afu) 302 { 303 struct cxl_context *ctx; 304 int tmp; 305 306 mutex_lock(&afu->contexts_lock); 307 idr_for_each_entry(&afu->contexts_idr, ctx, tmp) { 308 /* 309 * Anything done in here needs to be setup before the IDR is 310 * created and torn down after the IDR removed 311 */ 312 cxl_context_detach(ctx); 313 314 /* 315 * We are force detaching - remove any active PSA mappings so 316 * userspace cannot interfere with the card if it comes back. 317 * Easiest way to exercise this is to unbind and rebind the 318 * driver via sysfs while it is in use. 319 */ 320 mutex_lock(&ctx->mapping_lock); 321 if (ctx->mapping) 322 unmap_mapping_range(ctx->mapping, 0, 0, 1); 323 mutex_unlock(&ctx->mapping_lock); 324 } 325 mutex_unlock(&afu->contexts_lock); 326 } 327 328 static void reclaim_ctx(struct rcu_head *rcu) 329 { 330 struct cxl_context *ctx = container_of(rcu, struct cxl_context, rcu); 331 332 if (cxl_is_power8()) 333 free_page((u64)ctx->sstp); 334 if (ctx->ff_page) 335 __free_page(ctx->ff_page); 336 ctx->sstp = NULL; 337 338 kfree(ctx->irq_bitmap); 339 340 /* Drop ref to the afu device taken during cxl_context_init */ 341 cxl_afu_put(ctx->afu); 342 343 kfree(ctx); 344 } 345 346 void cxl_context_free(struct cxl_context *ctx) 347 { 348 if (ctx->kernelapi && ctx->mapping) 349 cxl_release_mapping(ctx); 350 mutex_lock(&ctx->afu->contexts_lock); 351 idr_remove(&ctx->afu->contexts_idr, ctx->pe); 352 mutex_unlock(&ctx->afu->contexts_lock); 353 call_rcu(&ctx->rcu, reclaim_ctx); 354 } 355 356 void cxl_context_mm_count_get(struct cxl_context *ctx) 357 { 358 if (ctx->mm) 359 atomic_inc(&ctx->mm->mm_count); 360 } 361 362 void cxl_context_mm_count_put(struct cxl_context *ctx) 363 { 364 if (ctx->mm) 365 mmdrop(ctx->mm); 366 } 367