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