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