1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright 2014 IBM Corp. 4 */ 5 6 #include <linux/module.h> 7 #include <linux/kernel.h> 8 #include <linux/bitmap.h> 9 #include <linux/sched.h> 10 #include <linux/pid.h> 11 #include <linux/fs.h> 12 #include <linux/mm.h> 13 #include <linux/debugfs.h> 14 #include <linux/slab.h> 15 #include <linux/idr.h> 16 #include <linux/sched/mm.h> 17 #include <linux/mmu_context.h> 18 #include <asm/cputable.h> 19 #include <asm/current.h> 20 #include <asm/copro.h> 21 22 #include "cxl.h" 23 24 /* 25 * Allocates space for a CXL context. 26 */ 27 struct cxl_context *cxl_context_alloc(void) 28 { 29 return kzalloc(sizeof(struct cxl_context), GFP_KERNEL); 30 } 31 32 /* 33 * Initialises a CXL context. 34 */ 35 int cxl_context_init(struct cxl_context *ctx, struct cxl_afu *afu, bool master) 36 { 37 int i; 38 39 ctx->afu = afu; 40 ctx->master = master; 41 ctx->pid = NULL; /* Set in start work ioctl */ 42 mutex_init(&ctx->mapping_lock); 43 ctx->mapping = NULL; 44 ctx->tidr = 0; 45 ctx->assign_tidr = false; 46 47 if (cxl_is_power8()) { 48 spin_lock_init(&ctx->sste_lock); 49 50 /* 51 * Allocate the segment table before we put it in the IDR so that we 52 * can always access it when dereferenced from IDR. For the same 53 * reason, the segment table is only destroyed after the context is 54 * removed from the IDR. Access to this in the IOCTL is protected by 55 * Linux filesystem semantics (can't IOCTL until open is complete). 56 */ 57 i = cxl_alloc_sst(ctx); 58 if (i) 59 return i; 60 } 61 62 INIT_WORK(&ctx->fault_work, cxl_handle_fault); 63 64 init_waitqueue_head(&ctx->wq); 65 spin_lock_init(&ctx->lock); 66 67 ctx->irq_bitmap = NULL; 68 ctx->pending_irq = false; 69 ctx->pending_fault = false; 70 ctx->pending_afu_err = false; 71 72 INIT_LIST_HEAD(&ctx->irq_names); 73 74 /* 75 * When we have to destroy all contexts in cxl_context_detach_all() we 76 * end up with afu_release_irqs() called from inside a 77 * idr_for_each_entry(). Hence we need to make sure that anything 78 * dereferenced from this IDR is ok before we allocate the IDR here. 79 * This clears out the IRQ ranges to ensure this. 80 */ 81 for (i = 0; i < CXL_IRQ_RANGES; i++) 82 ctx->irqs.range[i] = 0; 83 84 mutex_init(&ctx->status_mutex); 85 86 ctx->status = OPENED; 87 88 /* 89 * Allocating IDR! We better make sure everything's setup that 90 * dereferences from it. 91 */ 92 mutex_lock(&afu->contexts_lock); 93 idr_preload(GFP_KERNEL); 94 i = idr_alloc(&ctx->afu->contexts_idr, ctx, 0, 95 ctx->afu->num_procs, GFP_NOWAIT); 96 idr_preload_end(); 97 mutex_unlock(&afu->contexts_lock); 98 if (i < 0) 99 return i; 100 101 ctx->pe = i; 102 if (cpu_has_feature(CPU_FTR_HVMODE)) { 103 ctx->elem = &ctx->afu->native->spa[i]; 104 ctx->external_pe = ctx->pe; 105 } else { 106 ctx->external_pe = -1; /* assigned when attaching */ 107 } 108 ctx->pe_inserted = false; 109 110 /* 111 * take a ref on the afu so that it stays alive at-least till 112 * this context is reclaimed inside reclaim_ctx. 113 */ 114 cxl_afu_get(afu); 115 return 0; 116 } 117 118 void cxl_context_set_mapping(struct cxl_context *ctx, 119 struct address_space *mapping) 120 { 121 mutex_lock(&ctx->mapping_lock); 122 ctx->mapping = mapping; 123 mutex_unlock(&ctx->mapping_lock); 124 } 125 126 static vm_fault_t cxl_mmap_fault(struct vm_fault *vmf) 127 { 128 struct vm_area_struct *vma = vmf->vma; 129 struct cxl_context *ctx = vma->vm_file->private_data; 130 u64 area, offset; 131 vm_fault_t ret; 132 133 offset = vmf->pgoff << PAGE_SHIFT; 134 135 pr_devel("%s: pe: %i address: 0x%lx offset: 0x%llx\n", 136 __func__, ctx->pe, vmf->address, offset); 137 138 if (ctx->afu->current_mode == CXL_MODE_DEDICATED) { 139 area = ctx->afu->psn_phys; 140 if (offset >= ctx->afu->adapter->ps_size) 141 return VM_FAULT_SIGBUS; 142 } else { 143 area = ctx->psn_phys; 144 if (offset >= ctx->psn_size) 145 return VM_FAULT_SIGBUS; 146 } 147 148 mutex_lock(&ctx->status_mutex); 149 150 if (ctx->status != STARTED) { 151 mutex_unlock(&ctx->status_mutex); 152 pr_devel("%s: Context not started, failing problem state access\n", __func__); 153 if (ctx->mmio_err_ff) { 154 if (!ctx->ff_page) { 155 ctx->ff_page = alloc_page(GFP_USER); 156 if (!ctx->ff_page) 157 return VM_FAULT_OOM; 158 memset(page_address(ctx->ff_page), 0xff, PAGE_SIZE); 159 } 160 get_page(ctx->ff_page); 161 vmf->page = ctx->ff_page; 162 vma->vm_page_prot = pgprot_cached(vma->vm_page_prot); 163 return 0; 164 } 165 return VM_FAULT_SIGBUS; 166 } 167 168 ret = vmf_insert_pfn(vma, vmf->address, (area + offset) >> PAGE_SHIFT); 169 170 mutex_unlock(&ctx->status_mutex); 171 172 return ret; 173 } 174 175 static const struct vm_operations_struct cxl_mmap_vmops = { 176 .fault = cxl_mmap_fault, 177 }; 178 179 /* 180 * Map a per-context mmio space into the given vma. 181 */ 182 int cxl_context_iomap(struct cxl_context *ctx, struct vm_area_struct *vma) 183 { 184 u64 start = vma->vm_pgoff << PAGE_SHIFT; 185 u64 len = vma->vm_end - vma->vm_start; 186 187 if (ctx->afu->current_mode == CXL_MODE_DEDICATED) { 188 if (start + len > ctx->afu->adapter->ps_size) 189 return -EINVAL; 190 191 if (cxl_is_power9()) { 192 /* 193 * Make sure there is a valid problem state 194 * area space for this AFU. 195 */ 196 if (ctx->master && !ctx->afu->psa) { 197 pr_devel("AFU doesn't support mmio space\n"); 198 return -EINVAL; 199 } 200 201 /* Can't mmap until the AFU is enabled */ 202 if (!ctx->afu->enabled) 203 return -EBUSY; 204 } 205 } else { 206 if (start + len > ctx->psn_size) 207 return -EINVAL; 208 209 /* Make sure there is a valid per process space for this AFU */ 210 if ((ctx->master && !ctx->afu->psa) || (!ctx->afu->pp_psa)) { 211 pr_devel("AFU doesn't support mmio space\n"); 212 return -EINVAL; 213 } 214 215 /* Can't mmap until the AFU is enabled */ 216 if (!ctx->afu->enabled) 217 return -EBUSY; 218 } 219 220 pr_devel("%s: mmio physical: %llx pe: %i master:%i\n", __func__, 221 ctx->psn_phys, ctx->pe , ctx->master); 222 223 vma->vm_flags |= VM_IO | VM_PFNMAP; 224 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); 225 vma->vm_ops = &cxl_mmap_vmops; 226 return 0; 227 } 228 229 /* 230 * Detach a context from the hardware. This disables interrupts and doesn't 231 * return until all outstanding interrupts for this context have completed. The 232 * hardware should no longer access *ctx after this has returned. 233 */ 234 int __detach_context(struct cxl_context *ctx) 235 { 236 enum cxl_context_status status; 237 238 mutex_lock(&ctx->status_mutex); 239 status = ctx->status; 240 ctx->status = CLOSED; 241 mutex_unlock(&ctx->status_mutex); 242 if (status != STARTED) 243 return -EBUSY; 244 245 /* Only warn if we detached while the link was OK. 246 * If detach fails when hw is down, we don't care. 247 */ 248 WARN_ON(cxl_ops->detach_process(ctx) && 249 cxl_ops->link_ok(ctx->afu->adapter, ctx->afu)); 250 flush_work(&ctx->fault_work); /* Only needed for dedicated process */ 251 252 /* 253 * Wait until no further interrupts are presented by the PSL 254 * for this context. 255 */ 256 if (cxl_ops->irq_wait) 257 cxl_ops->irq_wait(ctx); 258 259 /* release the reference to the group leader and mm handling pid */ 260 put_pid(ctx->pid); 261 262 cxl_ctx_put(); 263 264 /* Decrease the attached context count on the adapter */ 265 cxl_adapter_context_put(ctx->afu->adapter); 266 267 /* Decrease the mm count on the context */ 268 cxl_context_mm_count_put(ctx); 269 if (ctx->mm) 270 mm_context_remove_copro(ctx->mm); 271 ctx->mm = NULL; 272 273 return 0; 274 } 275 276 /* 277 * Detach the given context from the AFU. This doesn't actually 278 * free the context but it should stop the context running in hardware 279 * (ie. prevent this context from generating any further interrupts 280 * so that it can be freed). 281 */ 282 void cxl_context_detach(struct cxl_context *ctx) 283 { 284 int rc; 285 286 rc = __detach_context(ctx); 287 if (rc) 288 return; 289 290 afu_release_irqs(ctx, ctx); 291 wake_up_all(&ctx->wq); 292 } 293 294 /* 295 * Detach all contexts on the given AFU. 296 */ 297 void cxl_context_detach_all(struct cxl_afu *afu) 298 { 299 struct cxl_context *ctx; 300 int tmp; 301 302 mutex_lock(&afu->contexts_lock); 303 idr_for_each_entry(&afu->contexts_idr, ctx, tmp) { 304 /* 305 * Anything done in here needs to be setup before the IDR is 306 * created and torn down after the IDR removed 307 */ 308 cxl_context_detach(ctx); 309 310 /* 311 * We are force detaching - remove any active PSA mappings so 312 * userspace cannot interfere with the card if it comes back. 313 * Easiest way to exercise this is to unbind and rebind the 314 * driver via sysfs while it is in use. 315 */ 316 mutex_lock(&ctx->mapping_lock); 317 if (ctx->mapping) 318 unmap_mapping_range(ctx->mapping, 0, 0, 1); 319 mutex_unlock(&ctx->mapping_lock); 320 } 321 mutex_unlock(&afu->contexts_lock); 322 } 323 324 static void reclaim_ctx(struct rcu_head *rcu) 325 { 326 struct cxl_context *ctx = container_of(rcu, struct cxl_context, rcu); 327 328 if (cxl_is_power8()) 329 free_page((u64)ctx->sstp); 330 if (ctx->ff_page) 331 __free_page(ctx->ff_page); 332 ctx->sstp = NULL; 333 334 bitmap_free(ctx->irq_bitmap); 335 336 /* Drop ref to the afu device taken during cxl_context_init */ 337 cxl_afu_put(ctx->afu); 338 339 kfree(ctx); 340 } 341 342 void cxl_context_free(struct cxl_context *ctx) 343 { 344 if (ctx->kernelapi && ctx->mapping) 345 cxl_release_mapping(ctx); 346 mutex_lock(&ctx->afu->contexts_lock); 347 idr_remove(&ctx->afu->contexts_idr, ctx->pe); 348 mutex_unlock(&ctx->afu->contexts_lock); 349 call_rcu(&ctx->rcu, reclaim_ctx); 350 } 351 352 void cxl_context_mm_count_get(struct cxl_context *ctx) 353 { 354 if (ctx->mm) 355 mmgrab(ctx->mm); 356 } 357 358 void cxl_context_mm_count_put(struct cxl_context *ctx) 359 { 360 if (ctx->mm) 361 mmdrop(ctx->mm); 362 } 363