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