drivers/misc/ocxl/context.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 // Copyright 2017 IBM Corp.
   3 #include <linux/sched/mm.h>
   4 #include "trace.h"
   5 #include "ocxl_internal.h"
   6
   7 struct ocxl_context *ocxl_context_alloc(void)
   8 {
   9         return kzalloc(sizeof(struct ocxl_context), GFP_KERNEL);
  10 }
  11
  12 int ocxl_context_init(struct ocxl_context *ctx, struct ocxl_afu *afu,
  13                 struct address_space *mapping)
  14 {
  15         int pasid;
  16
  17         ctx->afu = afu;
  18         mutex_lock(&afu->contexts_lock);
  19         pasid = idr_alloc(&afu->contexts_idr, ctx, afu->pasid_base,
  20                         afu->pasid_base + afu->pasid_max, GFP_KERNEL);
  21         if (pasid < 0) {
  22                 mutex_unlock(&afu->contexts_lock);
  23                 return pasid;
  24         }
  25         afu->pasid_count++;
  26         mutex_unlock(&afu->contexts_lock);
  27
  28         ctx->pasid = pasid;
  29         ctx->status = OPENED;
  30         mutex_init(&ctx->status_mutex);
  31         ctx->mapping = mapping;
  32         mutex_init(&ctx->mapping_lock);
  33         init_waitqueue_head(&ctx->events_wq);
  34         mutex_init(&ctx->xsl_error_lock);
  35         mutex_init(&ctx->irq_lock);
  36         idr_init(&ctx->irq_idr);
  37         ctx->tidr = 0;
  38
  39         /*
  40          * Keep a reference on the AFU to make sure it's valid for the
  41          * duration of the life of the context
  42          */
  43         ocxl_afu_get(afu);
  44         return 0;
  45 }
  46
  47 /*
  48  * Callback for when a translation fault triggers an error
  49  * data:        a pointer to the context which triggered the fault
  50  * addr:        the address that triggered the error
  51  * dsisr:       the value of the PPC64 dsisr register
  52  */
  53 static void xsl_fault_error(void *data, u64 addr, u64 dsisr)
  54 {
  55         struct ocxl_context *ctx = (struct ocxl_context *) data;
  56
  57         mutex_lock(&ctx->xsl_error_lock);
  58         ctx->xsl_error.addr = addr;
  59         ctx->xsl_error.dsisr = dsisr;
  60         ctx->xsl_error.count++;
  61         mutex_unlock(&ctx->xsl_error_lock);
  62
  63         wake_up_all(&ctx->events_wq);
  64 }
  65
  66 int ocxl_context_attach(struct ocxl_context *ctx, u64 amr)
  67 {
  68         int rc;
  69
  70         // Locks both status & tidr
  71         mutex_lock(&ctx->status_mutex);
  72         if (ctx->status != OPENED) {
  73                 rc = -EIO;
  74                 goto out;
  75         }
  76
  77         rc = ocxl_link_add_pe(ctx->afu->fn->link, ctx->pasid,
  78                         current->mm->context.id, ctx->tidr, amr, current->mm,
  79                         xsl_fault_error, ctx);
  80         if (rc)
  81                 goto out;
  82
  83         ctx->status = ATTACHED;
  84 out:
  85         mutex_unlock(&ctx->status_mutex);
  86         return rc;
  87 }
  88
  89 static int map_afu_irq(struct vm_area_struct *vma, unsigned long address,
  90                 u64 offset, struct ocxl_context *ctx)
  91 {
  92         u64 trigger_addr;
  93
  94         trigger_addr = ocxl_afu_irq_get_addr(ctx, offset);
  95         if (!trigger_addr)
  96                 return VM_FAULT_SIGBUS;
  97
  98         vm_insert_pfn(vma, address, trigger_addr >> PAGE_SHIFT);
  99         return VM_FAULT_NOPAGE;
 100 }
 101
 102 static int map_pp_mmio(struct vm_area_struct *vma, unsigned long address,
 103                 u64 offset, struct ocxl_context *ctx)
 104 {
 105         u64 pp_mmio_addr;
 106         int pasid_off;
 107
 108         if (offset >= ctx->afu->config.pp_mmio_stride)
 109                 return VM_FAULT_SIGBUS;
 110
 111         mutex_lock(&ctx->status_mutex);
 112         if (ctx->status != ATTACHED) {
 113                 mutex_unlock(&ctx->status_mutex);
 114                 pr_debug("%s: Context not attached, failing mmio mmap\n",
 115                         __func__);
 116                 return VM_FAULT_SIGBUS;
 117         }
 118
 119         pasid_off = ctx->pasid - ctx->afu->pasid_base;
 120         pp_mmio_addr = ctx->afu->pp_mmio_start +
 121                 pasid_off * ctx->afu->config.pp_mmio_stride +
 122                 offset;
 123
 124         vm_insert_pfn(vma, address, pp_mmio_addr >> PAGE_SHIFT);
 125         mutex_unlock(&ctx->status_mutex);
 126         return VM_FAULT_NOPAGE;
 127 }
 128
 129 static int ocxl_mmap_fault(struct vm_fault *vmf)
 130 {
 131         struct vm_area_struct *vma = vmf->vma;
 132         struct ocxl_context *ctx = vma->vm_file->private_data;
 133         u64 offset;
 134         int rc;
 135
 136         offset = vmf->pgoff << PAGE_SHIFT;
 137         pr_debug("%s: pasid %d address 0x%lx offset 0x%llx\n", __func__,
 138                 ctx->pasid, vmf->address, offset);
 139
 140         if (offset < ctx->afu->irq_base_offset)
 141                 rc = map_pp_mmio(vma, vmf->address, offset, ctx);
 142         else
 143                 rc = map_afu_irq(vma, vmf->address, offset, ctx);
 144         return rc;
 145 }
 146
 147 static const struct vm_operations_struct ocxl_vmops = {
 148         .fault = ocxl_mmap_fault,
 149 };
 150
 151 static int check_mmap_afu_irq(struct ocxl_context *ctx,
 152                         struct vm_area_struct *vma)
 153 {
 154         /* only one page */
 155         if (vma_pages(vma) != 1)
 156                 return -EINVAL;
 157
 158         /* check offset validty */
 159         if (!ocxl_afu_irq_get_addr(ctx, vma->vm_pgoff << PAGE_SHIFT))
 160                 return -EINVAL;
 161
 162         /*
 163          * trigger page should only be accessible in write mode.
 164          *
 165          * It's a bit theoretical, as a page mmaped with only
 166          * PROT_WRITE is currently readable, but it doesn't hurt.
 167          */
 168         if ((vma->vm_flags & VM_READ) || (vma->vm_flags & VM_EXEC) ||
 169                 !(vma->vm_flags & VM_WRITE))
 170                 return -EINVAL;
 171         vma->vm_flags &= ~(VM_MAYREAD | VM_MAYEXEC);
 172         return 0;
 173 }
 174
 175 static int check_mmap_mmio(struct ocxl_context *ctx,
 176                         struct vm_area_struct *vma)
 177 {
 178         if ((vma_pages(vma) + vma->vm_pgoff) >
 179                 (ctx->afu->config.pp_mmio_stride >> PAGE_SHIFT))
 180                 return -EINVAL;
 181         return 0;
 182 }
 183
 184 int ocxl_context_mmap(struct ocxl_context *ctx, struct vm_area_struct *vma)
 185 {
 186         int rc;
 187
 188         if ((vma->vm_pgoff << PAGE_SHIFT) < ctx->afu->irq_base_offset)
 189                 rc = check_mmap_mmio(ctx, vma);
 190         else
 191                 rc = check_mmap_afu_irq(ctx, vma);
 192         if (rc)
 193                 return rc;
 194
 195         vma->vm_flags |= VM_IO | VM_PFNMAP;
 196         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 197         vma->vm_ops = &ocxl_vmops;
 198         return 0;
 199 }
 200
 201 int ocxl_context_detach(struct ocxl_context *ctx)
 202 {
 203         struct pci_dev *dev;
 204         int afu_control_pos;
 205         enum ocxl_context_status status;
 206         int rc;
 207
 208         mutex_lock(&ctx->status_mutex);
 209         status = ctx->status;
 210         ctx->status = CLOSED;
 211         mutex_unlock(&ctx->status_mutex);
 212         if (status != ATTACHED)
 213                 return 0;
 214
 215         dev = to_pci_dev(ctx->afu->fn->dev.parent);
 216         afu_control_pos = ctx->afu->config.dvsec_afu_control_pos;
 217
 218         mutex_lock(&ctx->afu->afu_control_lock);
 219         rc = ocxl_config_terminate_pasid(dev, afu_control_pos, ctx->pasid);
 220         mutex_unlock(&ctx->afu->afu_control_lock);
 221         trace_ocxl_terminate_pasid(ctx->pasid, rc);
 222         if (rc) {
 223                 /*
 224                  * If we timeout waiting for the AFU to terminate the
 225                  * pasid, then it's dangerous to clean up the Process
 226                  * Element entry in the SPA, as it may be referenced
 227                  * in the future by the AFU. In which case, we would
 228                  * checkstop because of an invalid PE access (FIR
 229                  * register 2, bit 42). So leave the PE
 230                  * defined. Caller shouldn't free the context so that
 231                  * PASID remains allocated.
 232                  *
 233                  * A link reset will be required to cleanup the AFU
 234                  * and the SPA.
 235                  */
 236                 if (rc == -EBUSY)
 237                         return rc;
 238         }
 239         rc = ocxl_link_remove_pe(ctx->afu->fn->link, ctx->pasid);
 240         if (rc) {
 241                 dev_warn(&ctx->afu->dev,
 242                         "Couldn't remove PE entry cleanly: %d\n", rc);
 243         }
 244         return 0;
 245 }
 246
 247 void ocxl_context_detach_all(struct ocxl_afu *afu)
 248 {
 249         struct ocxl_context *ctx;
 250         int tmp;
 251
 252         mutex_lock(&afu->contexts_lock);
 253         idr_for_each_entry(&afu->contexts_idr, ctx, tmp) {
 254                 ocxl_context_detach(ctx);
 255                 /*
 256                  * We are force detaching - remove any active mmio
 257                  * mappings so userspace cannot interfere with the
 258                  * card if it comes back.  Easiest way to exercise
 259                  * this is to unbind and rebind the driver via sysfs
 260                  * while it is in use.
 261                  */
 262                 mutex_lock(&ctx->mapping_lock);
 263                 if (ctx->mapping)
 264                         unmap_mapping_range(ctx->mapping, 0, 0, 1);
 265                 mutex_unlock(&ctx->mapping_lock);
 266         }
 267         mutex_unlock(&afu->contexts_lock);
 268 }
 269
 270 void ocxl_context_free(struct ocxl_context *ctx)
 271 {
 272         mutex_lock(&ctx->afu->contexts_lock);
 273         ctx->afu->pasid_count--;
 274         idr_remove(&ctx->afu->contexts_idr, ctx->pasid);
 275         mutex_unlock(&ctx->afu->contexts_lock);
 276
 277         ocxl_afu_irq_free_all(ctx);
 278         idr_destroy(&ctx->irq_idr);
 279         /* reference to the AFU taken in ocxl_context_init */
 280         ocxl_afu_put(ctx->afu);
 281         kfree(ctx);
 282 }