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         get_dma_buf(shm->dmabuf);
 207         fd = dma_buf_fd(shm->dmabuf, O_CLOEXEC);
 208         if (fd < 0)
 209                 dma_buf_put(shm->dmabuf);
 210         return fd;
 211 }
 212
 213 /**
 214  * tee_shm_free() - Free shared memory
 215  * @shm:        Handle to shared memory to free
 216  */
 217 void tee_shm_free(struct tee_shm *shm)
 218 {
 219         /*
 220          * dma_buf_put() decreases the dmabuf reference counter and will
 221          * call tee_shm_release() when the last reference is gone.
 222          *
 223          * In the case of driver private memory we call tee_shm_release
 224          * directly instead as it doesn't have a reference counter.
 225          */
 226         if (shm->flags & TEE_SHM_DMA_BUF)
 227                 dma_buf_put(shm->dmabuf);
 228         else
 229                 tee_shm_release(shm);
 230 }
 231 EXPORT_SYMBOL_GPL(tee_shm_free);
 232
 233 /**
 234  * tee_shm_va2pa() - Get physical address of a virtual address
 235  * @shm:        Shared memory handle
 236  * @va:         Virtual address to tranlsate
 237  * @pa:         Returned physical address
 238  * @returns 0 on success and < 0 on failure
 239  */
 240 int tee_shm_va2pa(struct tee_shm *shm, void *va, phys_addr_t *pa)
 241 {
 242         /* Check that we're in the range of the shm */
 243         if ((char *)va < (char *)shm->kaddr)
 244                 return -EINVAL;
 245         if ((char *)va >= ((char *)shm->kaddr + shm->size))
 246                 return -EINVAL;
 247
 248         return tee_shm_get_pa(
 249                         shm, (unsigned long)va - (unsigned long)shm->kaddr, pa);
 250 }
 251 EXPORT_SYMBOL_GPL(tee_shm_va2pa);
 252
 253 /**
 254  * tee_shm_pa2va() - Get virtual address of a physical address
 255  * @shm:        Shared memory handle
 256  * @pa:         Physical address to tranlsate
 257  * @va:         Returned virtual address
 258  * @returns 0 on success and < 0 on failure
 259  */
 260 int tee_shm_pa2va(struct tee_shm *shm, phys_addr_t pa, void **va)
 261 {
 262         /* Check that we're in the range of the shm */
 263         if (pa < shm->paddr)
 264                 return -EINVAL;
 265         if (pa >= (shm->paddr + shm->size))
 266                 return -EINVAL;
 267
 268         if (va) {
 269                 void *v = tee_shm_get_va(shm, pa - shm->paddr);
 270
 271                 if (IS_ERR(v))
 272                         return PTR_ERR(v);
 273                 *va = v;
 274         }
 275         return 0;
 276 }
 277 EXPORT_SYMBOL_GPL(tee_shm_pa2va);
 278
 279 /**
 280  * tee_shm_get_va() - Get virtual address of a shared memory plus an offset
 281  * @shm:        Shared memory handle
 282  * @offs:       Offset from start of this shared memory
 283  * @returns virtual address of the shared memory + offs if offs is within
 284  *      the bounds of this shared memory, else an ERR_PTR
 285  */
 286 void *tee_shm_get_va(struct tee_shm *shm, size_t offs)
 287 {
 288         if (offs >= shm->size)
 289                 return ERR_PTR(-EINVAL);
 290         return (char *)shm->kaddr + offs;
 291 }
 292 EXPORT_SYMBOL_GPL(tee_shm_get_va);
 293
 294 /**
 295  * tee_shm_get_pa() - Get physical address of a shared memory plus an offset
 296  * @shm:        Shared memory handle
 297  * @offs:       Offset from start of this shared memory
 298  * @pa:         Physical address to return
 299  * @returns 0 if offs is within the bounds of this shared memory, else an
 300  *      error code.
 301  */
 302 int tee_shm_get_pa(struct tee_shm *shm, size_t offs, phys_addr_t *pa)
 303 {
 304         if (offs >= shm->size)
 305                 return -EINVAL;
 306         if (pa)
 307                 *pa = shm->paddr + offs;
 308         return 0;
 309 }
 310 EXPORT_SYMBOL_GPL(tee_shm_get_pa);
 311
 312 /**
 313  * tee_shm_get_from_id() - Find shared memory object and increase reference
 314  * count
 315  * @ctx:        Context owning the shared memory
 316  * @id:         Id of shared memory object
 317  * @returns a pointer to 'struct tee_shm' on success or an ERR_PTR on failure
 318  */
 319 struct tee_shm *tee_shm_get_from_id(struct tee_context *ctx, int id)
 320 {
 321         struct tee_device *teedev;
 322         struct tee_shm *shm;
 323
 324         if (!ctx)
 325                 return ERR_PTR(-EINVAL);
 326
 327         teedev = ctx->teedev;
 328         mutex_lock(&teedev->mutex);
 329         shm = idr_find(&teedev->idr, id);
 330         if (!shm || shm->ctx != ctx)
 331                 shm = ERR_PTR(-EINVAL);
 332         else if (shm->flags & TEE_SHM_DMA_BUF)
 333                 get_dma_buf(shm->dmabuf);
 334         mutex_unlock(&teedev->mutex);
 335         return shm;
 336 }
 337 EXPORT_SYMBOL_GPL(tee_shm_get_from_id);
 338
 339 /**
 340  * tee_shm_get_id() - Get id of a shared memory object
 341  * @shm:        Shared memory handle
 342  * @returns id
 343  */
 344 int tee_shm_get_id(struct tee_shm *shm)
 345 {
 346         return shm->id;
 347 }
 348 EXPORT_SYMBOL_GPL(tee_shm_get_id);
 349
 350 /**
 351  * tee_shm_put() - Decrease reference count on a shared memory handle
 352  * @shm:        Shared memory handle
 353  */
 354 void tee_shm_put(struct tee_shm *shm)
 355 {
 356         if (shm->flags & TEE_SHM_DMA_BUF)
 357                 dma_buf_put(shm->dmabuf);
 358 }
 359 EXPORT_SYMBOL_GPL(tee_shm_put);