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, ctx->afu->adapter->min_pe, 94 ctx->afu->num_procs, GFP_NOWAIT); 95 idr_preload_end(); 96 mutex_unlock(&afu->contexts_lock); 97 if (i < 0) 98 return i; 99 100 ctx->pe = i; 101 if (cpu_has_feature(CPU_FTR_HVMODE)) { 102 ctx->elem = &ctx->afu->native->spa[i]; 103 ctx->external_pe = ctx->pe; 104 } else { 105 ctx->external_pe = -1; /* assigned when attaching */ 106 } 107 ctx->pe_inserted = false; 108 109 /* 110 * take a ref on the afu so that it stays alive at-least till 111 * this context is reclaimed inside reclaim_ctx. 112 */ 113 cxl_afu_get(afu); 114 return 0; 115 } 116 117 static int cxl_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 118 { 119 struct cxl_context *ctx = vma->vm_file->private_data; 120 unsigned long address = (unsigned long)vmf->virtual_address; 121 u64 area, offset; 122 123 offset = vmf->pgoff << PAGE_SHIFT; 124 125 pr_devel("%s: pe: %i address: 0x%lx offset: 0x%llx\n", 126 __func__, ctx->pe, address, offset); 127 128 if (ctx->afu->current_mode == CXL_MODE_DEDICATED) { 129 area = ctx->afu->psn_phys; 130 if (offset >= ctx->afu->adapter->ps_size) 131 return VM_FAULT_SIGBUS; 132 } else { 133 area = ctx->psn_phys; 134 if (offset >= ctx->psn_size) 135 return VM_FAULT_SIGBUS; 136 } 137 138 mutex_lock(&ctx->status_mutex); 139 140 if (ctx->status != STARTED) { 141 mutex_unlock(&ctx->status_mutex); 142 pr_devel("%s: Context not started, failing problem state access\n", __func__); 143 if (ctx->mmio_err_ff) { 144 if (!ctx->ff_page) { 145 ctx->ff_page = alloc_page(GFP_USER); 146 if (!ctx->ff_page) 147 return VM_FAULT_OOM; 148 memset(page_address(ctx->ff_page), 0xff, PAGE_SIZE); 149 } 150 get_page(ctx->ff_page); 151 vmf->page = ctx->ff_page; 152 vma->vm_page_prot = pgprot_cached(vma->vm_page_prot); 153 return 0; 154 } 155 return VM_FAULT_SIGBUS; 156 } 157 158 vm_insert_pfn(vma, address, (area + offset) >> PAGE_SHIFT); 159 160 mutex_unlock(&ctx->status_mutex); 161 162 return VM_FAULT_NOPAGE; 163 } 164 165 static const struct vm_operations_struct cxl_mmap_vmops = { 166 .fault = cxl_mmap_fault, 167 }; 168 169 /* 170 * Map a per-context mmio space into the given vma. 171 */ 172 int cxl_context_iomap(struct cxl_context *ctx, struct vm_area_struct *vma) 173 { 174 u64 start = vma->vm_pgoff << PAGE_SHIFT; 175 u64 len = vma->vm_end - vma->vm_start; 176 177 if (ctx->afu->current_mode == CXL_MODE_DEDICATED) { 178 if (start + len > ctx->afu->adapter->ps_size) 179 return -EINVAL; 180 } else { 181 if (start + len > ctx->psn_size) 182 return -EINVAL; 183 } 184 185 if (ctx->afu->current_mode != CXL_MODE_DEDICATED) { 186 /* make sure there is a valid per process space for this AFU */ 187 if ((ctx->master && !ctx->afu->psa) || (!ctx->afu->pp_psa)) { 188 pr_devel("AFU doesn't support mmio space\n"); 189 return -EINVAL; 190 } 191 192 /* Can't mmap until the AFU is enabled */ 193 if (!ctx->afu->enabled) 194 return -EBUSY; 195 } 196 197 pr_devel("%s: mmio physical: %llx pe: %i master:%i\n", __func__, 198 ctx->psn_phys, ctx->pe , ctx->master); 199 200 vma->vm_flags |= VM_IO | VM_PFNMAP; 201 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); 202 vma->vm_ops = &cxl_mmap_vmops; 203 return 0; 204 } 205 206 /* 207 * Detach a context from the hardware. This disables interrupts and doesn't 208 * return until all outstanding interrupts for this context have completed. The 209 * hardware should no longer access *ctx after this has returned. 210 */ 211 int __detach_context(struct cxl_context *ctx) 212 { 213 enum cxl_context_status status; 214 215 mutex_lock(&ctx->status_mutex); 216 status = ctx->status; 217 ctx->status = CLOSED; 218 mutex_unlock(&ctx->status_mutex); 219 if (status != STARTED) 220 return -EBUSY; 221 222 /* Only warn if we detached while the link was OK. 223 * If detach fails when hw is down, we don't care. 224 */ 225 WARN_ON(cxl_ops->detach_process(ctx) && 226 cxl_ops->link_ok(ctx->afu->adapter, ctx->afu)); 227 flush_work(&ctx->fault_work); /* Only needed for dedicated process */ 228 229 /* 230 * Wait until no further interrupts are presented by the PSL 231 * for this context. 232 */ 233 if (cxl_ops->irq_wait) 234 cxl_ops->irq_wait(ctx); 235 236 /* release the reference to the group leader and mm handling pid */ 237 put_pid(ctx->pid); 238 put_pid(ctx->glpid); 239 240 cxl_ctx_put(); 241 return 0; 242 } 243 244 /* 245 * Detach the given context from the AFU. This doesn't actually 246 * free the context but it should stop the context running in hardware 247 * (ie. prevent this context from generating any further interrupts 248 * so that it can be freed). 249 */ 250 void cxl_context_detach(struct cxl_context *ctx) 251 { 252 int rc; 253 254 rc = __detach_context(ctx); 255 if (rc) 256 return; 257 258 afu_release_irqs(ctx, ctx); 259 wake_up_all(&ctx->wq); 260 } 261 262 /* 263 * Detach all contexts on the given AFU. 264 */ 265 void cxl_context_detach_all(struct cxl_afu *afu) 266 { 267 struct cxl_context *ctx; 268 int tmp; 269 270 mutex_lock(&afu->contexts_lock); 271 idr_for_each_entry(&afu->contexts_idr, ctx, tmp) { 272 /* 273 * Anything done in here needs to be setup before the IDR is 274 * created and torn down after the IDR removed 275 */ 276 cxl_context_detach(ctx); 277 278 /* 279 * We are force detaching - remove any active PSA mappings so 280 * userspace cannot interfere with the card if it comes back. 281 * Easiest way to exercise this is to unbind and rebind the 282 * driver via sysfs while it is in use. 283 */ 284 mutex_lock(&ctx->mapping_lock); 285 if (ctx->mapping) 286 unmap_mapping_range(ctx->mapping, 0, 0, 1); 287 mutex_unlock(&ctx->mapping_lock); 288 } 289 mutex_unlock(&afu->contexts_lock); 290 } 291 292 static void reclaim_ctx(struct rcu_head *rcu) 293 { 294 struct cxl_context *ctx = container_of(rcu, struct cxl_context, rcu); 295 296 free_page((u64)ctx->sstp); 297 if (ctx->ff_page) 298 __free_page(ctx->ff_page); 299 ctx->sstp = NULL; 300 if (ctx->kernelapi) 301 kfree(ctx->mapping); 302 303 kfree(ctx->irq_bitmap); 304 305 /* Drop ref to the afu device taken during cxl_context_init */ 306 cxl_afu_put(ctx->afu); 307 308 kfree(ctx); 309 } 310 311 void cxl_context_free(struct cxl_context *ctx) 312 { 313 mutex_lock(&ctx->afu->contexts_lock); 314 idr_remove(&ctx->afu->contexts_idr, ctx->pe); 315 mutex_unlock(&ctx->afu->contexts_lock); 316 call_rcu(&ctx->rcu, reclaim_ctx); 317 } 318