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 <asm/cputable.h> 22 #include <asm/current.h> 23 #include <asm/copro.h> 24 25 #include "cxl.h" 26 27 /* 28 * Allocates space for a CXL context. 29 */ 30 struct cxl_context *cxl_context_alloc(void) 31 { 32 return kzalloc(sizeof(struct cxl_context), GFP_KERNEL); 33 } 34 35 /* 36 * Initialises a CXL context. 37 */ 38 int cxl_context_init(struct cxl_context *ctx, struct cxl_afu *afu, bool master) 39 { 40 int i; 41 42 ctx->afu = afu; 43 ctx->master = master; 44 ctx->pid = NULL; /* Set in start work ioctl */ 45 mutex_init(&ctx->mapping_lock); 46 ctx->mapping = NULL; 47 48 if (cxl_is_psl8(afu)) { 49 spin_lock_init(&ctx->sste_lock); 50 51 /* 52 * Allocate the segment table before we put it in the IDR so that we 53 * can always access it when dereferenced from IDR. For the same 54 * reason, the segment table is only destroyed after the context is 55 * removed from the IDR. Access to this in the IOCTL is protected by 56 * Linux filesytem symantics (can't IOCTL until open is complete). 57 */ 58 i = cxl_alloc_sst(ctx); 59 if (i) 60 return i; 61 } 62 63 INIT_WORK(&ctx->fault_work, cxl_handle_fault); 64 65 init_waitqueue_head(&ctx->wq); 66 spin_lock_init(&ctx->lock); 67 68 ctx->irq_bitmap = NULL; 69 ctx->pending_irq = false; 70 ctx->pending_fault = false; 71 ctx->pending_afu_err = false; 72 73 INIT_LIST_HEAD(&ctx->irq_names); 74 INIT_LIST_HEAD(&ctx->extra_irq_contexts); 75 76 /* 77 * When we have to destroy all contexts in cxl_context_detach_all() we 78 * end up with afu_release_irqs() called from inside a 79 * idr_for_each_entry(). Hence we need to make sure that anything 80 * dereferenced from this IDR is ok before we allocate the IDR here. 81 * This clears out the IRQ ranges to ensure this. 82 */ 83 for (i = 0; i < CXL_IRQ_RANGES; i++) 84 ctx->irqs.range[i] = 0; 85 86 mutex_init(&ctx->status_mutex); 87 88 ctx->status = OPENED; 89 90 /* 91 * Allocating IDR! We better make sure everything's setup that 92 * dereferences from it. 93 */ 94 mutex_lock(&afu->contexts_lock); 95 idr_preload(GFP_KERNEL); 96 i = idr_alloc(&ctx->afu->contexts_idr, ctx, ctx->afu->adapter->min_pe, 97 ctx->afu->num_procs, GFP_NOWAIT); 98 idr_preload_end(); 99 mutex_unlock(&afu->contexts_lock); 100 if (i < 0) 101 return i; 102 103 ctx->pe = i; 104 if (cpu_has_feature(CPU_FTR_HVMODE)) { 105 ctx->elem = &ctx->afu->native->spa[i]; 106 ctx->external_pe = ctx->pe; 107 } else { 108 ctx->external_pe = -1; /* assigned when attaching */ 109 } 110 ctx->pe_inserted = false; 111 112 /* 113 * take a ref on the afu so that it stays alive at-least till 114 * this context is reclaimed inside reclaim_ctx. 115 */ 116 cxl_afu_get(afu); 117 return 0; 118 } 119 120 void cxl_context_set_mapping(struct cxl_context *ctx, 121 struct address_space *mapping) 122 { 123 mutex_lock(&ctx->mapping_lock); 124 ctx->mapping = mapping; 125 mutex_unlock(&ctx->mapping_lock); 126 } 127 128 static int cxl_mmap_fault(struct vm_fault *vmf) 129 { 130 struct vm_area_struct *vma = vmf->vma; 131 struct cxl_context *ctx = vma->vm_file->private_data; 132 u64 area, offset; 133 134 offset = vmf->pgoff << PAGE_SHIFT; 135 136 pr_devel("%s: pe: %i address: 0x%lx offset: 0x%llx\n", 137 __func__, ctx->pe, vmf->address, offset); 138 139 if (ctx->afu->current_mode == CXL_MODE_DEDICATED) { 140 area = ctx->afu->psn_phys; 141 if (offset >= ctx->afu->adapter->ps_size) 142 return VM_FAULT_SIGBUS; 143 } else { 144 area = ctx->psn_phys; 145 if (offset >= ctx->psn_size) 146 return VM_FAULT_SIGBUS; 147 } 148 149 mutex_lock(&ctx->status_mutex); 150 151 if (ctx->status != STARTED) { 152 mutex_unlock(&ctx->status_mutex); 153 pr_devel("%s: Context not started, failing problem state access\n", __func__); 154 if (ctx->mmio_err_ff) { 155 if (!ctx->ff_page) { 156 ctx->ff_page = alloc_page(GFP_USER); 157 if (!ctx->ff_page) 158 return VM_FAULT_OOM; 159 memset(page_address(ctx->ff_page), 0xff, PAGE_SIZE); 160 } 161 get_page(ctx->ff_page); 162 vmf->page = ctx->ff_page; 163 vma->vm_page_prot = pgprot_cached(vma->vm_page_prot); 164 return 0; 165 } 166 return VM_FAULT_SIGBUS; 167 } 168 169 vm_insert_pfn(vma, vmf->address, (area + offset) >> PAGE_SHIFT); 170 171 mutex_unlock(&ctx->status_mutex); 172 173 return VM_FAULT_NOPAGE; 174 } 175 176 static const struct vm_operations_struct cxl_mmap_vmops = { 177 .fault = cxl_mmap_fault, 178 }; 179 180 /* 181 * Map a per-context mmio space into the given vma. 182 */ 183 int cxl_context_iomap(struct cxl_context *ctx, struct vm_area_struct *vma) 184 { 185 u64 start = vma->vm_pgoff << PAGE_SHIFT; 186 u64 len = vma->vm_end - vma->vm_start; 187 188 if (ctx->afu->current_mode == CXL_MODE_DEDICATED) { 189 if (start + len > ctx->afu->adapter->ps_size) 190 return -EINVAL; 191 192 if (cxl_is_psl9(ctx->afu)) { 193 /* 194 * Make sure there is a valid problem state 195 * area space for this AFU. 196 */ 197 if (ctx->master && !ctx->afu->psa) { 198 pr_devel("AFU doesn't support mmio space\n"); 199 return -EINVAL; 200 } 201 202 /* Can't mmap until the AFU is enabled */ 203 if (!ctx->afu->enabled) 204 return -EBUSY; 205 } 206 } else { 207 if (start + len > ctx->psn_size) 208 return -EINVAL; 209 210 /* Make sure there is a valid per process space for this AFU */ 211 if ((ctx->master && !ctx->afu->psa) || (!ctx->afu->pp_psa)) { 212 pr_devel("AFU doesn't support mmio space\n"); 213 return -EINVAL; 214 } 215 216 /* Can't mmap until the AFU is enabled */ 217 if (!ctx->afu->enabled) 218 return -EBUSY; 219 } 220 221 pr_devel("%s: mmio physical: %llx pe: %i master:%i\n", __func__, 222 ctx->psn_phys, ctx->pe , ctx->master); 223 224 vma->vm_flags |= VM_IO | VM_PFNMAP; 225 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); 226 vma->vm_ops = &cxl_mmap_vmops; 227 return 0; 228 } 229 230 /* 231 * Detach a context from the hardware. This disables interrupts and doesn't 232 * return until all outstanding interrupts for this context have completed. The 233 * hardware should no longer access *ctx after this has returned. 234 */ 235 int __detach_context(struct cxl_context *ctx) 236 { 237 enum cxl_context_status status; 238 239 mutex_lock(&ctx->status_mutex); 240 status = ctx->status; 241 ctx->status = CLOSED; 242 mutex_unlock(&ctx->status_mutex); 243 if (status != STARTED) 244 return -EBUSY; 245 246 /* Only warn if we detached while the link was OK. 247 * If detach fails when hw is down, we don't care. 248 */ 249 WARN_ON(cxl_ops->detach_process(ctx) && 250 cxl_ops->link_ok(ctx->afu->adapter, ctx->afu)); 251 flush_work(&ctx->fault_work); /* Only needed for dedicated process */ 252 253 /* 254 * Wait until no further interrupts are presented by the PSL 255 * for this context. 256 */ 257 if (cxl_ops->irq_wait) 258 cxl_ops->irq_wait(ctx); 259 260 /* release the reference to the group leader and mm handling pid */ 261 put_pid(ctx->pid); 262 263 cxl_ctx_put(); 264 265 /* Decrease the attached context count on the adapter */ 266 cxl_adapter_context_put(ctx->afu->adapter); 267 268 /* Decrease the mm count on the context */ 269 cxl_context_mm_count_put(ctx); 270 ctx->mm = NULL; 271 272 return 0; 273 } 274 275 /* 276 * Detach the given context from the AFU. This doesn't actually 277 * free the context but it should stop the context running in hardware 278 * (ie. prevent this context from generating any further interrupts 279 * so that it can be freed). 280 */ 281 void cxl_context_detach(struct cxl_context *ctx) 282 { 283 int rc; 284 285 rc = __detach_context(ctx); 286 if (rc) 287 return; 288 289 afu_release_irqs(ctx, ctx); 290 wake_up_all(&ctx->wq); 291 } 292 293 /* 294 * Detach all contexts on the given AFU. 295 */ 296 void cxl_context_detach_all(struct cxl_afu *afu) 297 { 298 struct cxl_context *ctx; 299 int tmp; 300 301 mutex_lock(&afu->contexts_lock); 302 idr_for_each_entry(&afu->contexts_idr, ctx, tmp) { 303 /* 304 * Anything done in here needs to be setup before the IDR is 305 * created and torn down after the IDR removed 306 */ 307 cxl_context_detach(ctx); 308 309 /* 310 * We are force detaching - remove any active PSA mappings so 311 * userspace cannot interfere with the card if it comes back. 312 * Easiest way to exercise this is to unbind and rebind the 313 * driver via sysfs while it is in use. 314 */ 315 mutex_lock(&ctx->mapping_lock); 316 if (ctx->mapping) 317 unmap_mapping_range(ctx->mapping, 0, 0, 1); 318 mutex_unlock(&ctx->mapping_lock); 319 } 320 mutex_unlock(&afu->contexts_lock); 321 } 322 323 static void reclaim_ctx(struct rcu_head *rcu) 324 { 325 struct cxl_context *ctx = container_of(rcu, struct cxl_context, rcu); 326 327 if (cxl_is_psl8(ctx->afu)) 328 free_page((u64)ctx->sstp); 329 if (ctx->ff_page) 330 __free_page(ctx->ff_page); 331 ctx->sstp = NULL; 332 333 kfree(ctx->irq_bitmap); 334 335 /* Drop ref to the afu device taken during cxl_context_init */ 336 cxl_afu_put(ctx->afu); 337 338 kfree(ctx); 339 } 340 341 void cxl_context_free(struct cxl_context *ctx) 342 { 343 if (ctx->kernelapi && ctx->mapping) 344 cxl_release_mapping(ctx); 345 mutex_lock(&ctx->afu->contexts_lock); 346 idr_remove(&ctx->afu->contexts_idr, ctx->pe); 347 mutex_unlock(&ctx->afu->contexts_lock); 348 call_rcu(&ctx->rcu, reclaim_ctx); 349 } 350 351 void cxl_context_mm_count_get(struct cxl_context *ctx) 352 { 353 if (ctx->mm) 354 atomic_inc(&ctx->mm->mm_count); 355 } 356 357 void cxl_context_mm_count_put(struct cxl_context *ctx) 358 { 359 if (ctx->mm) 360 mmdrop(ctx->mm); 361 } 362