drivers/tee/tee_shm.c

   1 /*
   2  * Copyright (c) 2015-2016, Linaro Limited
   3  *
   4  * This software is licensed under the terms of the GNU General Public
   5  * License version 2, as published by the Free Software Foundation, and
   6  * may be copied, distributed, and modified under those terms.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  */
  14 #include <linux/device.h>
  15 #include <linux/dma-buf.h>
  16 #include <linux/fdtable.h>
  17 #include <linux/idr.h>
  18 #include <linux/sched.h>
  19 #include <linux/slab.h>
  20 #include <linux/tee_drv.h>
  21 #include "tee_private.h"
  22
  23 static void tee_shm_release(struct tee_shm *shm)
  24 {
  25         struct tee_device *teedev = shm->teedev;
  26         struct tee_shm_pool_mgr *poolm;
  27
  28         mutex_lock(&teedev->mutex);
  29         idr_remove(&teedev->idr, shm->id);
  30         if (shm->ctx)
  31                 list_del(&shm->link);
  32         mutex_unlock(&teedev->mutex);
  33
  34         if (shm->flags & TEE_SHM_DMA_BUF)
  35                 poolm = &teedev->pool->dma_buf_mgr;
  36         else
  37                 poolm = &teedev->pool->private_mgr;
  38
  39         poolm->ops->free(poolm, shm);
  40         kfree(shm);
  41
  42         tee_device_put(teedev);
  43 }
  44
  45 static struct sg_table *tee_shm_op_map_dma_buf(struct dma_buf_attachment
  46                         *attach, enum dma_data_direction dir)
  47 {
  48         return NULL;
  49 }
  50
  51 static void tee_shm_op_unmap_dma_buf(struct dma_buf_attachment *attach,
  52                                      struct sg_table *table,
  53                                      enum dma_data_direction dir)
  54 {
  55 }
  56
  57 static void tee_shm_op_release(struct dma_buf *dmabuf)
  58 {
  59         struct tee_shm *shm = dmabuf->priv;
  60
  61         tee_shm_release(shm);
  62 }
  63
  64 static void *tee_shm_op_map_atomic(struct dma_buf *dmabuf, unsigned long pgnum)
  65 {
  66         return NULL;
  67 }
  68
  69 static void *tee_shm_op_map(struct dma_buf *dmabuf, unsigned long pgnum)
  70 {
  71         return NULL;
  72 }
  73
  74 static int tee_shm_op_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
  75 {
  76         struct tee_shm *shm = dmabuf->priv;
  77         size_t size = vma->vm_end - vma->vm_start;
  78
  79         return remap_pfn_range(vma, vma->vm_start, shm->paddr >> PAGE_SHIFT,
  80                                size, vma->vm_page_prot);
  81 }
  82
  83 static const struct dma_buf_ops tee_shm_dma_buf_ops = {
  84         .map_dma_buf = tee_shm_op_map_dma_buf,
  85         .unmap_dma_buf = tee_shm_op_unmap_dma_buf,
  86         .release = tee_shm_op_release,
  87         .map_atomic = tee_shm_op_map_atomic,
  88         .map = tee_shm_op_map,
  89         .mmap = tee_shm_op_mmap,
  90 };
  91
  92 /**
  93  * tee_shm_alloc() - Allocate shared memory
  94  * @ctx:        Context that allocates the shared memory
  95  * @size:       Requested size of shared memory
  96  * @flags:      Flags setting properties for the requested shared memory.
  97  *
  98  * Memory allocated as global shared memory is automatically freed when the
  99  * TEE file pointer is closed. The @flags field uses the bits defined by
 100  * TEE_SHM_* in <linux/tee_drv.h>. TEE_SHM_MAPPED must currently always be
 101  * set. If TEE_SHM_DMA_BUF global shared memory will be allocated and
 102  * associated with a dma-buf handle, else driver private memory.
 103  */
 104 struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags)
 105 {
 106         struct tee_device *teedev = ctx->teedev;
 107         struct tee_shm_pool_mgr *poolm = NULL;
 108         struct tee_shm *shm;
 109         void *ret;
 110         int rc;
 111
 112         if (!(flags & TEE_SHM_MAPPED)) {
 113                 dev_err(teedev->dev.parent,
 114                         "only mapped allocations supported\n");
 115                 return ERR_PTR(-EINVAL);
 116         }
 117
 118         if ((flags & ~(TEE_SHM_MAPPED | TEE_SHM_DMA_BUF))) {
 119                 dev_err(teedev->dev.parent, "invalid shm flags 0x%x", flags);
 120                 return ERR_PTR(-EINVAL);
 121         }
 122
 123         if (!tee_device_get(teedev))
 124                 return ERR_PTR(-EINVAL);
 125
 126         if (!teedev->pool) {
 127                 /* teedev has been detached from driver */
 128                 ret = ERR_PTR(-EINVAL);
 129                 goto err_dev_put;
 130         }
 131
 132         shm = kzalloc(sizeof(*shm), GFP_KERNEL);
 133         if (!shm) {
 134                 ret = ERR_PTR(-ENOMEM);
 135                 goto err_dev_put;
 136         }
 137
 138         shm->flags = flags;
 139         shm->teedev = teedev;
 140         shm->ctx = ctx;
 141         if (flags & TEE_SHM_DMA_BUF)
 142                 poolm = &teedev->pool->dma_buf_mgr;
 143         else
 144                 poolm = &teedev->pool->private_mgr;
 145
 146         rc = poolm->ops->alloc(poolm, shm, size);
 147         if (rc) {
 148                 ret = ERR_PTR(rc);
 149                 goto err_kfree;
 150         }
 151
 152         mutex_lock(&teedev->mutex);
 153         shm->id = idr_alloc(&teedev->idr, shm, 1, 0, GFP_KERNEL);
 154         mutex_unlock(&teedev->mutex);
 155         if (shm->id < 0) {
 156                 ret = ERR_PTR(shm->id);
 157                 goto err_pool_free;
 158         }
 159
 160         if (flags & TEE_SHM_DMA_BUF) {
 161                 DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
 162
 163                 exp_info.ops = &tee_shm_dma_buf_ops;
 164                 exp_info.size = shm->size;
 165                 exp_info.flags = O_RDWR;
 166                 exp_info.priv = shm;
 167
 168                 shm->dmabuf = dma_buf_export(&exp_info);
 169                 if (IS_ERR(shm->dmabuf)) {
 170                         ret = ERR_CAST(shm->dmabuf);
 171                         goto err_rem;
 172                 }
 173         }
 174         mutex_lock(&teedev->mutex);
 175         list_add_tail(&shm->link, &ctx->list_shm);
 176         mutex_unlock(&teedev->mutex);
 177
 178         return shm;
 179 err_rem:
 180         mutex_lock(&teedev->mutex);
 181         idr_remove(&teedev->idr, shm->id);
 182         mutex_unlock(&teedev->mutex);
 183 err_pool_free:
 184         poolm->ops->free(poolm, shm);
 185 err_kfree:
 186         kfree(shm);
 187 err_dev_put:
 188         tee_device_put(teedev);
 189         return ret;
 190 }
 191 EXPORT_SYMBOL_GPL(tee_shm_alloc);
 192
 193 /**
 194  * tee_shm_get_fd() - Increase reference count and return file descriptor
 195  * @shm:        Shared memory handle
 196  * @returns user space file descriptor to shared memory
 197  */
 198 int tee_shm_get_fd(struct tee_shm *shm)
 199 {
 200         u32 req_flags = TEE_SHM_MAPPED | TEE_SHM_DMA_BUF;
 201         int fd;
 202
 203         if ((shm->flags & req_flags) != req_flags)
 204                 return -EINVAL;
 205
 206         fd = dma_buf_fd(shm->dmabuf, O_CLOEXEC);
 207         if (fd >= 0)
 208                 get_dma_buf(shm->dmabuf);
 209         return fd;
 210 }
 211
 212 /**
 213  * tee_shm_free() - Free shared memory
 214  * @shm:        Handle to shared memory to free
 215  */
 216 void tee_shm_free(struct tee_shm *shm)
 217 {
 218         /*
 219          * dma_buf_put() decreases the dmabuf reference counter and will
 220          * call tee_shm_release() when the last reference is gone.
 221          *
 222          * In the case of driver private memory we call tee_shm_release
 223          * directly instead as it doesn't have a reference counter.
 224          */
 225         if (shm->flags & TEE_SHM_DMA_BUF)
 226                 dma_buf_put(shm->dmabuf);
 227         else
 228                 tee_shm_release(shm);
 229 }
 230 EXPORT_SYMBOL_GPL(tee_shm_free);
 231
 232 /**
 233  * tee_shm_va2pa() - Get physical address of a virtual address
 234  * @shm:        Shared memory handle
 235  * @va:         Virtual address to tranlsate
 236  * @pa:         Returned physical address
 237  * @returns 0 on success and < 0 on failure
 238  */
 239 int tee_shm_va2pa(struct tee_shm *shm, void *va, phys_addr_t *pa)
 240 {
 241         /* Check that we're in the range of the shm */
 242         if ((char *)va < (char *)shm->kaddr)
 243                 return -EINVAL;
 244         if ((char *)va >= ((char *)shm->kaddr + shm->size))
 245                 return -EINVAL;
 246
 247         return tee_shm_get_pa(
 248                         shm, (unsigned long)va - (unsigned long)shm->kaddr, pa);
 249 }
 250 EXPORT_SYMBOL_GPL(tee_shm_va2pa);
 251
 252 /**
 253  * tee_shm_pa2va() - Get virtual address of a physical address
 254  * @shm:        Shared memory handle
 255  * @pa:         Physical address to tranlsate
 256  * @va:         Returned virtual address
 257  * @returns 0 on success and < 0 on failure
 258  */
 259 int tee_shm_pa2va(struct tee_shm *shm, phys_addr_t pa, void **va)
 260 {
 261         /* Check that we're in the range of the shm */
 262         if (pa < shm->paddr)
 263                 return -EINVAL;
 264         if (pa >= (shm->paddr + shm->size))
 265                 return -EINVAL;
 266
 267         if (va) {
 268                 void *v = tee_shm_get_va(shm, pa - shm->paddr);
 269
 270                 if (IS_ERR(v))
 271                         return PTR_ERR(v);
 272                 *va = v;
 273         }
 274         return 0;
 275 }
 276 EXPORT_SYMBOL_GPL(tee_shm_pa2va);
 277
 278 /**
 279  * tee_shm_get_va() - Get virtual address of a shared memory plus an offset
 280  * @shm:        Shared memory handle
 281  * @offs:       Offset from start of this shared memory
 282  * @returns virtual address of the shared memory + offs if offs is within
 283  *      the bounds of this shared memory, else an ERR_PTR
 284  */
 285 void *tee_shm_get_va(struct tee_shm *shm, size_t offs)
 286 {
 287         if (offs >= shm->size)
 288                 return ERR_PTR(-EINVAL);
 289         return (char *)shm->kaddr + offs;
 290 }
 291 EXPORT_SYMBOL_GPL(tee_shm_get_va);
 292
 293 /**
 294  * tee_shm_get_pa() - Get physical address of a shared memory plus an offset
 295  * @shm:        Shared memory handle
 296  * @offs:       Offset from start of this shared memory
 297  * @pa:         Physical address to return
 298  * @returns 0 if offs is within the bounds of this shared memory, else an
 299  *      error code.
 300  */
 301 int tee_shm_get_pa(struct tee_shm *shm, size_t offs, phys_addr_t *pa)
 302 {
 303         if (offs >= shm->size)
 304                 return -EINVAL;
 305         if (pa)
 306                 *pa = shm->paddr + offs;
 307         return 0;
 308 }
 309 EXPORT_SYMBOL_GPL(tee_shm_get_pa);
 310
 311 /**
 312  * tee_shm_get_from_id() - Find shared memory object and increase reference
 313  * count
 314  * @ctx:        Context owning the shared memory
 315  * @id:         Id of shared memory object
 316  * @returns a pointer to 'struct tee_shm' on success or an ERR_PTR on failure
 317  */
 318 struct tee_shm *tee_shm_get_from_id(struct tee_context *ctx, int id)
 319 {
 320         struct tee_device *teedev;
 321         struct tee_shm *shm;
 322
 323         if (!ctx)
 324                 return ERR_PTR(-EINVAL);
 325
 326         teedev = ctx->teedev;
 327         mutex_lock(&teedev->mutex);
 328         shm = idr_find(&teedev->idr, id);
 329         if (!shm || shm->ctx != ctx)
 330                 shm = ERR_PTR(-EINVAL);
 331         else if (shm->flags & TEE_SHM_DMA_BUF)
 332                 get_dma_buf(shm->dmabuf);
 333         mutex_unlock(&teedev->mutex);
 334         return shm;
 335 }
 336 EXPORT_SYMBOL_GPL(tee_shm_get_from_id);
 337
 338 /**
 339  * tee_shm_get_id() - Get id of a shared memory object
 340  * @shm:        Shared memory handle
 341  * @returns id
 342  */
 343 int tee_shm_get_id(struct tee_shm *shm)
 344 {
 345         return shm->id;
 346 }
 347 EXPORT_SYMBOL_GPL(tee_shm_get_id);
 348
 349 /**
 350  * tee_shm_put() - Decrease reference count on a shared memory handle
 351  * @shm:        Shared memory handle
 352  */
 353 void tee_shm_put(struct tee_shm *shm)
 354 {
 355         if (shm->flags & TEE_SHM_DMA_BUF)
 356                 dma_buf_put(shm->dmabuf);
 357 }
 358 EXPORT_SYMBOL_GPL(tee_shm_put);