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 = 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 /* 71 * When we have to destroy all contexts in cxl_context_detach_all() we 72 * end up with afu_release_irqs() called from inside a 73 * idr_for_each_entry(). Hence we need to make sure that anything 74 * dereferenced from this IDR is ok before we allocate the IDR here. 75 * This clears out the IRQ ranges to ensure this. 76 */ 77 for (i = 0; i < CXL_IRQ_RANGES; i++) 78 ctx->irqs.range[i] = 0; 79 80 mutex_init(&ctx->status_mutex); 81 82 ctx->status = OPENED; 83 84 /* 85 * Allocating IDR! We better make sure everything's setup that 86 * dereferences from it. 87 */ 88 mutex_lock(&afu->contexts_lock); 89 idr_preload(GFP_KERNEL); 90 i = idr_alloc(&ctx->afu->contexts_idr, ctx, 0, 91 ctx->afu->num_procs, GFP_NOWAIT); 92 idr_preload_end(); 93 mutex_unlock(&afu->contexts_lock); 94 if (i < 0) 95 return i; 96 97 ctx->pe = i; 98 ctx->elem = &ctx->afu->spa[i]; 99 ctx->pe_inserted = false; 100 101 /* 102 * take a ref on the afu so that it stays alive at-least till 103 * this context is reclaimed inside reclaim_ctx. 104 */ 105 cxl_afu_get(afu); 106 return 0; 107 } 108 109 static int cxl_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 110 { 111 struct cxl_context *ctx = vma->vm_file->private_data; 112 unsigned long address = (unsigned long)vmf->virtual_address; 113 u64 area, offset; 114 115 offset = vmf->pgoff << PAGE_SHIFT; 116 117 pr_devel("%s: pe: %i address: 0x%lx offset: 0x%llx\n", 118 __func__, ctx->pe, address, offset); 119 120 if (ctx->afu->current_mode == CXL_MODE_DEDICATED) { 121 area = ctx->afu->psn_phys; 122 if (offset >= ctx->afu->adapter->ps_size) 123 return VM_FAULT_SIGBUS; 124 } else { 125 area = ctx->psn_phys; 126 if (offset >= ctx->psn_size) 127 return VM_FAULT_SIGBUS; 128 } 129 130 mutex_lock(&ctx->status_mutex); 131 132 if (ctx->status != STARTED) { 133 mutex_unlock(&ctx->status_mutex); 134 pr_devel("%s: Context not started, failing problem state access\n", __func__); 135 if (ctx->mmio_err_ff) { 136 if (!ctx->ff_page) { 137 ctx->ff_page = alloc_page(GFP_USER); 138 if (!ctx->ff_page) 139 return VM_FAULT_OOM; 140 memset(page_address(ctx->ff_page), 0xff, PAGE_SIZE); 141 } 142 get_page(ctx->ff_page); 143 vmf->page = ctx->ff_page; 144 vma->vm_page_prot = pgprot_cached(vma->vm_page_prot); 145 return 0; 146 } 147 return VM_FAULT_SIGBUS; 148 } 149 150 vm_insert_pfn(vma, address, (area + offset) >> PAGE_SHIFT); 151 152 mutex_unlock(&ctx->status_mutex); 153 154 return VM_FAULT_NOPAGE; 155 } 156 157 static const struct vm_operations_struct cxl_mmap_vmops = { 158 .fault = cxl_mmap_fault, 159 }; 160 161 /* 162 * Map a per-context mmio space into the given vma. 163 */ 164 int cxl_context_iomap(struct cxl_context *ctx, struct vm_area_struct *vma) 165 { 166 u64 start = vma->vm_pgoff << PAGE_SHIFT; 167 u64 len = vma->vm_end - vma->vm_start; 168 169 if (ctx->afu->current_mode == CXL_MODE_DEDICATED) { 170 if (start + len > ctx->afu->adapter->ps_size) 171 return -EINVAL; 172 } else { 173 if (start + len > ctx->psn_size) 174 return -EINVAL; 175 } 176 177 if (ctx->afu->current_mode != CXL_MODE_DEDICATED) { 178 /* make sure there is a valid per process space for this AFU */ 179 if ((ctx->master && !ctx->afu->psa) || (!ctx->afu->pp_psa)) { 180 pr_devel("AFU doesn't support mmio space\n"); 181 return -EINVAL; 182 } 183 184 /* Can't mmap until the AFU is enabled */ 185 if (!ctx->afu->enabled) 186 return -EBUSY; 187 } 188 189 pr_devel("%s: mmio physical: %llx pe: %i master:%i\n", __func__, 190 ctx->psn_phys, ctx->pe , ctx->master); 191 192 vma->vm_flags |= VM_IO | VM_PFNMAP; 193 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); 194 vma->vm_ops = &cxl_mmap_vmops; 195 return 0; 196 } 197 198 /* 199 * Detach a context from the hardware. This disables interrupts and doesn't 200 * return until all outstanding interrupts for this context have completed. The 201 * hardware should no longer access *ctx after this has returned. 202 */ 203 int __detach_context(struct cxl_context *ctx) 204 { 205 enum cxl_context_status status; 206 207 mutex_lock(&ctx->status_mutex); 208 status = ctx->status; 209 ctx->status = CLOSED; 210 mutex_unlock(&ctx->status_mutex); 211 if (status != STARTED) 212 return -EBUSY; 213 214 /* Only warn if we detached while the link was OK. 215 * If detach fails when hw is down, we don't care. 216 */ 217 WARN_ON(cxl_detach_process(ctx) && 218 cxl_adapter_link_ok(ctx->afu->adapter)); 219 flush_work(&ctx->fault_work); /* Only needed for dedicated process */ 220 put_pid(ctx->pid); 221 cxl_ctx_put(); 222 return 0; 223 } 224 225 /* 226 * Detach the given context from the AFU. This doesn't actually 227 * free the context but it should stop the context running in hardware 228 * (ie. prevent this context from generating any further interrupts 229 * so that it can be freed). 230 */ 231 void cxl_context_detach(struct cxl_context *ctx) 232 { 233 int rc; 234 235 rc = __detach_context(ctx); 236 if (rc) 237 return; 238 239 afu_release_irqs(ctx, ctx); 240 wake_up_all(&ctx->wq); 241 } 242 243 /* 244 * Detach all contexts on the given AFU. 245 */ 246 void cxl_context_detach_all(struct cxl_afu *afu) 247 { 248 struct cxl_context *ctx; 249 int tmp; 250 251 mutex_lock(&afu->contexts_lock); 252 idr_for_each_entry(&afu->contexts_idr, ctx, tmp) { 253 /* 254 * Anything done in here needs to be setup before the IDR is 255 * created and torn down after the IDR removed 256 */ 257 cxl_context_detach(ctx); 258 259 /* 260 * We are force detaching - remove any active PSA mappings so 261 * userspace cannot interfere with the card if it comes back. 262 * Easiest way to exercise this is to unbind and rebind the 263 * driver via sysfs while it is in use. 264 */ 265 mutex_lock(&ctx->mapping_lock); 266 if (ctx->mapping) 267 unmap_mapping_range(ctx->mapping, 0, 0, 1); 268 mutex_unlock(&ctx->mapping_lock); 269 } 270 mutex_unlock(&afu->contexts_lock); 271 } 272 273 static void reclaim_ctx(struct rcu_head *rcu) 274 { 275 struct cxl_context *ctx = container_of(rcu, struct cxl_context, rcu); 276 277 free_page((u64)ctx->sstp); 278 if (ctx->ff_page) 279 __free_page(ctx->ff_page); 280 ctx->sstp = NULL; 281 if (ctx->kernelapi) 282 kfree(ctx->mapping); 283 284 if (ctx->irq_bitmap) 285 kfree(ctx->irq_bitmap); 286 287 /* Drop ref to the afu device taken during cxl_context_init */ 288 cxl_afu_put(ctx->afu); 289 290 kfree(ctx); 291 } 292 293 void cxl_context_free(struct cxl_context *ctx) 294 { 295 mutex_lock(&ctx->afu->contexts_lock); 296 idr_remove(&ctx->afu->contexts_idr, ctx->pe); 297 mutex_unlock(&ctx->afu->contexts_lock); 298 call_rcu(&ctx->rcu, reclaim_ctx); 299 } 300