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 int ocxl_context_alloc(struct ocxl_context **context, struct ocxl_afu *afu,
   8                 struct address_space *mapping)
   9 {
  10         int pasid;
  11         struct ocxl_context *ctx;
  12
  13         ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
  14         if (!ctx)
  15                 return -ENOMEM;
  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                 kfree(ctx);
  24                 return pasid;
  25         }
  26         afu->pasid_count++;
  27         mutex_unlock(&afu->contexts_lock);
  28
  29         ctx->pasid = pasid;
  30         ctx->status = OPENED;
  31         mutex_init(&ctx->status_mutex);
  32         ctx->mapping = mapping;
  33         mutex_init(&ctx->mapping_lock);
  34         init_waitqueue_head(&ctx->events_wq);
  35         mutex_init(&ctx->xsl_error_lock);
  36         mutex_init(&ctx->irq_lock);
  37         idr_init(&ctx->irq_idr);
  38         ctx->tidr = 0;
  39
  40         /*
  41          * Keep a reference on the AFU to make sure it's valid for the
  42          * duration of the life of the context
  43          */
  44         ocxl_afu_get(afu);
  45         *context = ctx;
  46         return 0;
  47 }
  48 EXPORT_SYMBOL_GPL(ocxl_context_alloc);
  49
  50 /*
  51  * Callback for when a translation fault triggers an error
  52  * data:        a pointer to the context which triggered the fault
  53  * addr:        the address that triggered the error
  54  * dsisr:       the value of the PPC64 dsisr register
  55  */
  56 static void xsl_fault_error(void *data, u64 addr, u64 dsisr)
  57 {
  58         struct ocxl_context *ctx = data;
  59
  60         mutex_lock(&ctx->xsl_error_lock);
  61         ctx->xsl_error.addr = addr;
  62         ctx->xsl_error.dsisr = dsisr;
  63         ctx->xsl_error.count++;
  64         mutex_unlock(&ctx->xsl_error_lock);
  65
  66         wake_up_all(&ctx->events_wq);
  67 }
  68
  69 int ocxl_context_attach(struct ocxl_context *ctx, u64 amr, struct mm_struct *mm)
  70 {
  71         int rc;
  72         unsigned long pidr = 0;
  73         struct pci_dev *dev;
  74
  75         // Locks both status & tidr
  76         mutex_lock(&ctx->status_mutex);
  77         if (ctx->status != OPENED) {
  78                 rc = -EIO;
  79                 goto out;
  80         }
  81
  82         if (mm)
  83                 pidr = mm->context.id;
  84
  85         dev = to_pci_dev(ctx->afu->fn->dev.parent);
  86         rc = ocxl_link_add_pe(ctx->afu->fn->link, ctx->pasid, pidr, ctx->tidr,
  87                               amr, pci_dev_id(dev), mm, xsl_fault_error, ctx);
  88         if (rc)
  89                 goto out;
  90
  91         ctx->status = ATTACHED;
  92 out:
  93         mutex_unlock(&ctx->status_mutex);
  94         return rc;
  95 }
  96 EXPORT_SYMBOL_GPL(ocxl_context_attach);
  97
  98 static vm_fault_t map_afu_irq(struct vm_area_struct *vma, unsigned long address,
  99                 u64 offset, struct ocxl_context *ctx)
 100 {
 101         u64 trigger_addr;
 102         int irq_id = ocxl_irq_offset_to_id(ctx, offset);
 103
 104         trigger_addr = ocxl_afu_irq_get_addr(ctx, irq_id);
 105         if (!trigger_addr)
 106                 return VM_FAULT_SIGBUS;
 107
 108         return vmf_insert_pfn(vma, address, trigger_addr >> PAGE_SHIFT);
 109 }
 110
 111 static vm_fault_t map_pp_mmio(struct vm_area_struct *vma, unsigned long address,
 112                 u64 offset, struct ocxl_context *ctx)
 113 {
 114         u64 pp_mmio_addr;
 115         int pasid_off;
 116         vm_fault_t ret;
 117
 118         if (offset >= ctx->afu->config.pp_mmio_stride)
 119                 return VM_FAULT_SIGBUS;
 120
 121         mutex_lock(&ctx->status_mutex);
 122         if (ctx->status != ATTACHED) {
 123                 mutex_unlock(&ctx->status_mutex);
 124                 pr_debug("%s: Context not attached, failing mmio mmap\n",
 125                         __func__);
 126                 return VM_FAULT_SIGBUS;
 127         }
 128
 129         pasid_off = ctx->pasid - ctx->afu->pasid_base;
 130         pp_mmio_addr = ctx->afu->pp_mmio_start +
 131                 pasid_off * ctx->afu->config.pp_mmio_stride +
 132                 offset;
 133
 134         ret = vmf_insert_pfn(vma, address, pp_mmio_addr >> PAGE_SHIFT);
 135         mutex_unlock(&ctx->status_mutex);
 136         return ret;
 137 }
 138
 139 static vm_fault_t ocxl_mmap_fault(struct vm_fault *vmf)
 140 {
 141         struct vm_area_struct *vma = vmf->vma;
 142         struct ocxl_context *ctx = vma->vm_file->private_data;
 143         u64 offset;
 144         vm_fault_t ret;
 145
 146         offset = vmf->pgoff << PAGE_SHIFT;
 147         pr_debug("%s: pasid %d address 0x%lx offset 0x%llx\n", __func__,
 148                 ctx->pasid, vmf->address, offset);
 149
 150         if (offset < ctx->afu->irq_base_offset)
 151                 ret = map_pp_mmio(vma, vmf->address, offset, ctx);
 152         else
 153                 ret = map_afu_irq(vma, vmf->address, offset, ctx);
 154         return ret;
 155 }
 156
 157 static const struct vm_operations_struct ocxl_vmops = {
 158         .fault = ocxl_mmap_fault,
 159 };
 160
 161 static int check_mmap_afu_irq(struct ocxl_context *ctx,
 162                         struct vm_area_struct *vma)
 163 {
 164         int irq_id = ocxl_irq_offset_to_id(ctx, vma->vm_pgoff << PAGE_SHIFT);
 165
 166         /* only one page */
 167         if (vma_pages(vma) != 1)
 168                 return -EINVAL;
 169
 170         /* check offset validty */
 171         if (!ocxl_afu_irq_get_addr(ctx, irq_id))
 172                 return -EINVAL;
 173
 174         /*
 175          * trigger page should only be accessible in write mode.
 176          *
 177          * It's a bit theoretical, as a page mmaped with only
 178          * PROT_WRITE is currently readable, but it doesn't hurt.
 179          */
 180         if ((vma->vm_flags & VM_READ) || (vma->vm_flags & VM_EXEC) ||
 181                 !(vma->vm_flags & VM_WRITE))
 182                 return -EINVAL;
 183         vm_flags_clear(vma, VM_MAYREAD | VM_MAYEXEC);
 184         return 0;
 185 }
 186
 187 static int check_mmap_mmio(struct ocxl_context *ctx,
 188                         struct vm_area_struct *vma)
 189 {
 190         if ((vma_pages(vma) + vma->vm_pgoff) >
 191                 (ctx->afu->config.pp_mmio_stride >> PAGE_SHIFT))
 192                 return -EINVAL;
 193         return 0;
 194 }
 195
 196 int ocxl_context_mmap(struct ocxl_context *ctx, struct vm_area_struct *vma)
 197 {
 198         int rc;
 199
 200         if ((vma->vm_pgoff << PAGE_SHIFT) < ctx->afu->irq_base_offset)
 201                 rc = check_mmap_mmio(ctx, vma);
 202         else
 203                 rc = check_mmap_afu_irq(ctx, vma);
 204         if (rc)
 205                 return rc;
 206
 207         vm_flags_set(vma, VM_IO | VM_PFNMAP);
 208         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 209         vma->vm_ops = &ocxl_vmops;
 210         return 0;
 211 }
 212
 213 int ocxl_context_detach(struct ocxl_context *ctx)
 214 {
 215         struct pci_dev *dev;
 216         int afu_control_pos;
 217         enum ocxl_context_status status;
 218         int rc;
 219
 220         mutex_lock(&ctx->status_mutex);
 221         status = ctx->status;
 222         ctx->status = CLOSED;
 223         mutex_unlock(&ctx->status_mutex);
 224         if (status != ATTACHED)
 225                 return 0;
 226
 227         dev = to_pci_dev(ctx->afu->fn->dev.parent);
 228         afu_control_pos = ctx->afu->config.dvsec_afu_control_pos;
 229
 230         mutex_lock(&ctx->afu->afu_control_lock);
 231         rc = ocxl_config_terminate_pasid(dev, afu_control_pos, ctx->pasid);
 232         mutex_unlock(&ctx->afu->afu_control_lock);
 233         trace_ocxl_terminate_pasid(ctx->pasid, rc);
 234         if (rc) {
 235                 /*
 236                  * If we timeout waiting for the AFU to terminate the
 237                  * pasid, then it's dangerous to clean up the Process
 238                  * Element entry in the SPA, as it may be referenced
 239                  * in the future by the AFU. In which case, we would
 240                  * checkstop because of an invalid PE access (FIR
 241                  * register 2, bit 42). So leave the PE
 242                  * defined. Caller shouldn't free the context so that
 243                  * PASID remains allocated.
 244                  *
 245                  * A link reset will be required to cleanup the AFU
 246                  * and the SPA.
 247                  */
 248                 if (rc == -EBUSY)
 249                         return rc;
 250         }
 251         rc = ocxl_link_remove_pe(ctx->afu->fn->link, ctx->pasid);
 252         if (rc) {
 253                 dev_warn(&dev->dev,
 254                         "Couldn't remove PE entry cleanly: %d\n", rc);
 255         }
 256         return 0;
 257 }
 258 EXPORT_SYMBOL_GPL(ocxl_context_detach);
 259
 260 void ocxl_context_detach_all(struct ocxl_afu *afu)
 261 {
 262         struct ocxl_context *ctx;
 263         int tmp;
 264
 265         mutex_lock(&afu->contexts_lock);
 266         idr_for_each_entry(&afu->contexts_idr, ctx, tmp) {
 267                 ocxl_context_detach(ctx);
 268                 /*
 269                  * We are force detaching - remove any active mmio
 270                  * mappings so userspace cannot interfere with the
 271                  * card if it comes back.  Easiest way to exercise
 272                  * this is to unbind and rebind the driver via sysfs
 273                  * while it is in use.
 274                  */
 275                 mutex_lock(&ctx->mapping_lock);
 276                 if (ctx->mapping)
 277                         unmap_mapping_range(ctx->mapping, 0, 0, 1);
 278                 mutex_unlock(&ctx->mapping_lock);
 279         }
 280         mutex_unlock(&afu->contexts_lock);
 281 }
 282
 283 void ocxl_context_free(struct ocxl_context *ctx)
 284 {
 285         mutex_lock(&ctx->afu->contexts_lock);
 286         ctx->afu->pasid_count--;
 287         idr_remove(&ctx->afu->contexts_idr, ctx->pasid);
 288         mutex_unlock(&ctx->afu->contexts_lock);
 289
 290         ocxl_afu_irq_free_all(ctx);
 291         idr_destroy(&ctx->irq_idr);
 292         /* reference to the AFU taken in ocxl_context_alloc() */
 293         ocxl_afu_put(ctx->afu);
 294         kfree(ctx);
 295 }
 296 EXPORT_SYMBOL_GPL(ocxl_context_free);