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 return 0; 101 } 102 103 static int cxl_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 104 { 105 struct cxl_context *ctx = vma->vm_file->private_data; 106 unsigned long address = (unsigned long)vmf->virtual_address; 107 u64 area, offset; 108 109 offset = vmf->pgoff << PAGE_SHIFT; 110 111 pr_devel("%s: pe: %i address: 0x%lx offset: 0x%llx\n", 112 __func__, ctx->pe, address, offset); 113 114 if (ctx->afu->current_mode == CXL_MODE_DEDICATED) { 115 area = ctx->afu->psn_phys; 116 if (offset > ctx->afu->adapter->ps_size) 117 return VM_FAULT_SIGBUS; 118 } else { 119 area = ctx->psn_phys; 120 if (offset > ctx->psn_size) 121 return VM_FAULT_SIGBUS; 122 } 123 124 mutex_lock(&ctx->status_mutex); 125 126 if (ctx->status != STARTED) { 127 mutex_unlock(&ctx->status_mutex); 128 pr_devel("%s: Context not started, failing problem state access\n", __func__); 129 return VM_FAULT_SIGBUS; 130 } 131 132 vm_insert_pfn(vma, address, (area + offset) >> PAGE_SHIFT); 133 134 mutex_unlock(&ctx->status_mutex); 135 136 return VM_FAULT_NOPAGE; 137 } 138 139 static const struct vm_operations_struct cxl_mmap_vmops = { 140 .fault = cxl_mmap_fault, 141 }; 142 143 /* 144 * Map a per-context mmio space into the given vma. 145 */ 146 int cxl_context_iomap(struct cxl_context *ctx, struct vm_area_struct *vma) 147 { 148 u64 len = vma->vm_end - vma->vm_start; 149 len = min(len, ctx->psn_size); 150 151 if (ctx->afu->current_mode != CXL_MODE_DEDICATED) { 152 /* make sure there is a valid per process space for this AFU */ 153 if ((ctx->master && !ctx->afu->psa) || (!ctx->afu->pp_psa)) { 154 pr_devel("AFU doesn't support mmio space\n"); 155 return -EINVAL; 156 } 157 158 /* Can't mmap until the AFU is enabled */ 159 if (!ctx->afu->enabled) 160 return -EBUSY; 161 } 162 163 pr_devel("%s: mmio physical: %llx pe: %i master:%i\n", __func__, 164 ctx->psn_phys, ctx->pe , ctx->master); 165 166 vma->vm_flags |= VM_IO | VM_PFNMAP; 167 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); 168 vma->vm_ops = &cxl_mmap_vmops; 169 return 0; 170 } 171 172 /* 173 * Detach a context from the hardware. This disables interrupts and doesn't 174 * return until all outstanding interrupts for this context have completed. The 175 * hardware should no longer access *ctx after this has returned. 176 */ 177 int __detach_context(struct cxl_context *ctx) 178 { 179 enum cxl_context_status status; 180 181 mutex_lock(&ctx->status_mutex); 182 status = ctx->status; 183 ctx->status = CLOSED; 184 mutex_unlock(&ctx->status_mutex); 185 if (status != STARTED) 186 return -EBUSY; 187 188 WARN_ON(cxl_detach_process(ctx)); 189 flush_work(&ctx->fault_work); /* Only needed for dedicated process */ 190 put_pid(ctx->pid); 191 cxl_ctx_put(); 192 return 0; 193 } 194 195 /* 196 * Detach the given context from the AFU. This doesn't actually 197 * free the context but it should stop the context running in hardware 198 * (ie. prevent this context from generating any further interrupts 199 * so that it can be freed). 200 */ 201 void cxl_context_detach(struct cxl_context *ctx) 202 { 203 int rc; 204 205 rc = __detach_context(ctx); 206 if (rc) 207 return; 208 209 afu_release_irqs(ctx, ctx); 210 wake_up_all(&ctx->wq); 211 } 212 213 /* 214 * Detach all contexts on the given AFU. 215 */ 216 void cxl_context_detach_all(struct cxl_afu *afu) 217 { 218 struct cxl_context *ctx; 219 int tmp; 220 221 mutex_lock(&afu->contexts_lock); 222 idr_for_each_entry(&afu->contexts_idr, ctx, tmp) { 223 /* 224 * Anything done in here needs to be setup before the IDR is 225 * created and torn down after the IDR removed 226 */ 227 cxl_context_detach(ctx); 228 229 /* 230 * We are force detaching - remove any active PSA mappings so 231 * userspace cannot interfere with the card if it comes back. 232 * Easiest way to exercise this is to unbind and rebind the 233 * driver via sysfs while it is in use. 234 */ 235 mutex_lock(&ctx->mapping_lock); 236 if (ctx->mapping) 237 unmap_mapping_range(ctx->mapping, 0, 0, 1); 238 mutex_unlock(&ctx->mapping_lock); 239 } 240 mutex_unlock(&afu->contexts_lock); 241 } 242 243 static void reclaim_ctx(struct rcu_head *rcu) 244 { 245 struct cxl_context *ctx = container_of(rcu, struct cxl_context, rcu); 246 247 free_page((u64)ctx->sstp); 248 ctx->sstp = NULL; 249 250 kfree(ctx); 251 } 252 253 void cxl_context_free(struct cxl_context *ctx) 254 { 255 mutex_lock(&ctx->afu->contexts_lock); 256 idr_remove(&ctx->afu->contexts_idr, ctx->pe); 257 mutex_unlock(&ctx->afu->contexts_lock); 258 call_rcu(&ctx->rcu, reclaim_ctx); 259 } 260