drivers/tee/tee_shm.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2015-2017, 2019-2021 Linaro Limited
   4  */
   5 #include <linux/anon_inodes.h>
   6 #include <linux/device.h>
   7 #include <linux/idr.h>
   8 #include <linux/mm.h>
   9 #include <linux/sched.h>
  10 #include <linux/slab.h>
  11 #include <linux/tee_drv.h>
  12 #include <linux/uio.h>
  13 #include "tee_private.h"
  14
  15 static void release_registered_pages(struct tee_shm *shm)
  16 {
  17         if (shm->pages) {
  18                 if (shm->flags & TEE_SHM_USER_MAPPED) {
  19                         unpin_user_pages(shm->pages, shm->num_pages);
  20                 } else {
  21                         size_t n;
  22
  23                         for (n = 0; n < shm->num_pages; n++)
  24                                 put_page(shm->pages[n]);
  25                 }
  26
  27                 kfree(shm->pages);
  28         }
  29 }
  30
  31 static void tee_shm_release(struct tee_device *teedev, struct tee_shm *shm)
  32 {
  33         if (shm->flags & TEE_SHM_POOL) {
  34                 struct tee_shm_pool_mgr *poolm;
  35
  36                 if (shm->flags & TEE_SHM_DMA_BUF)
  37                         poolm = teedev->pool->dma_buf_mgr;
  38                 else
  39                         poolm = teedev->pool->private_mgr;
  40
  41                 poolm->ops->free(poolm, shm);
  42         } else if (shm->flags & TEE_SHM_REGISTER) {
  43                 int rc = teedev->desc->ops->shm_unregister(shm->ctx, shm);
  44
  45                 if (rc)
  46                         dev_err(teedev->dev.parent,
  47                                 "unregister shm %p failed: %d", shm, rc);
  48
  49                 release_registered_pages(shm);
  50         }
  51
  52         teedev_ctx_put(shm->ctx);
  53
  54         kfree(shm);
  55
  56         tee_device_put(teedev);
  57 }
  58
  59 struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags)
  60 {
  61         struct tee_device *teedev = ctx->teedev;
  62         struct tee_shm_pool_mgr *poolm = NULL;
  63         struct tee_shm *shm;
  64         void *ret;
  65         int rc;
  66
  67         if (!(flags & TEE_SHM_MAPPED)) {
  68                 dev_err(teedev->dev.parent,
  69                         "only mapped allocations supported\n");
  70                 return ERR_PTR(-EINVAL);
  71         }
  72
  73         if ((flags & ~(TEE_SHM_MAPPED | TEE_SHM_DMA_BUF | TEE_SHM_PRIV))) {
  74                 dev_err(teedev->dev.parent, "invalid shm flags 0x%x", flags);
  75                 return ERR_PTR(-EINVAL);
  76         }
  77
  78         if (!tee_device_get(teedev))
  79                 return ERR_PTR(-EINVAL);
  80
  81         if (!teedev->pool) {
  82                 /* teedev has been detached from driver */
  83                 ret = ERR_PTR(-EINVAL);
  84                 goto err_dev_put;
  85         }
  86
  87         shm = kzalloc(sizeof(*shm), GFP_KERNEL);
  88         if (!shm) {
  89                 ret = ERR_PTR(-ENOMEM);
  90                 goto err_dev_put;
  91         }
  92
  93         refcount_set(&shm->refcount, 1);
  94         shm->flags = flags | TEE_SHM_POOL;
  95         shm->ctx = ctx;
  96         if (flags & TEE_SHM_DMA_BUF)
  97                 poolm = teedev->pool->dma_buf_mgr;
  98         else
  99                 poolm = teedev->pool->private_mgr;
 100
 101         rc = poolm->ops->alloc(poolm, shm, size);
 102         if (rc) {
 103                 ret = ERR_PTR(rc);
 104                 goto err_kfree;
 105         }
 106
 107         if (flags & TEE_SHM_DMA_BUF) {
 108                 mutex_lock(&teedev->mutex);
 109                 shm->id = idr_alloc(&teedev->idr, shm, 1, 0, GFP_KERNEL);
 110                 mutex_unlock(&teedev->mutex);
 111                 if (shm->id < 0) {
 112                         ret = ERR_PTR(shm->id);
 113                         goto err_pool_free;
 114                 }
 115         }
 116
 117         teedev_ctx_get(ctx);
 118
 119         return shm;
 120 err_pool_free:
 121         poolm->ops->free(poolm, shm);
 122 err_kfree:
 123         kfree(shm);
 124 err_dev_put:
 125         tee_device_put(teedev);
 126         return ret;
 127 }
 128 EXPORT_SYMBOL_GPL(tee_shm_alloc);
 129
 130 /**
 131  * tee_shm_alloc_kernel_buf() - Allocate shared memory for kernel buffer
 132  * @ctx:        Context that allocates the shared memory
 133  * @size:       Requested size of shared memory
 134  *
 135  * The returned memory registered in secure world and is suitable to be
 136  * passed as a memory buffer in parameter argument to
 137  * tee_client_invoke_func(). The memory allocated is later freed with a
 138  * call to tee_shm_free().
 139  *
 140  * @returns a pointer to 'struct tee_shm'
 141  */
 142 struct tee_shm *tee_shm_alloc_kernel_buf(struct tee_context *ctx, size_t size)
 143 {
 144         return tee_shm_alloc(ctx, size, TEE_SHM_MAPPED);
 145 }
 146 EXPORT_SYMBOL_GPL(tee_shm_alloc_kernel_buf);
 147
 148 struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr,
 149                                  size_t length, u32 flags)
 150 {
 151         struct tee_device *teedev = ctx->teedev;
 152         const u32 req_user_flags = TEE_SHM_DMA_BUF | TEE_SHM_USER_MAPPED;
 153         const u32 req_kernel_flags = TEE_SHM_DMA_BUF | TEE_SHM_KERNEL_MAPPED;
 154         struct tee_shm *shm;
 155         void *ret;
 156         int rc;
 157         int num_pages;
 158         unsigned long start;
 159
 160         if (flags != req_user_flags && flags != req_kernel_flags)
 161                 return ERR_PTR(-ENOTSUPP);
 162
 163         if (!tee_device_get(teedev))
 164                 return ERR_PTR(-EINVAL);
 165
 166         if (!teedev->desc->ops->shm_register ||
 167             !teedev->desc->ops->shm_unregister) {
 168                 tee_device_put(teedev);
 169                 return ERR_PTR(-ENOTSUPP);
 170         }
 171
 172         teedev_ctx_get(ctx);
 173
 174         shm = kzalloc(sizeof(*shm), GFP_KERNEL);
 175         if (!shm) {
 176                 ret = ERR_PTR(-ENOMEM);
 177                 goto err;
 178         }
 179
 180         refcount_set(&shm->refcount, 1);
 181         shm->flags = flags | TEE_SHM_REGISTER;
 182         shm->ctx = ctx;
 183         shm->id = -1;
 184         addr = untagged_addr(addr);
 185         start = rounddown(addr, PAGE_SIZE);
 186         shm->offset = addr - start;
 187         shm->size = length;
 188         num_pages = (roundup(addr + length, PAGE_SIZE) - start) / PAGE_SIZE;
 189         shm->pages = kcalloc(num_pages, sizeof(*shm->pages), GFP_KERNEL);
 190         if (!shm->pages) {
 191                 ret = ERR_PTR(-ENOMEM);
 192                 goto err;
 193         }
 194
 195         if (flags & TEE_SHM_USER_MAPPED) {
 196                 rc = pin_user_pages_fast(start, num_pages, FOLL_WRITE,
 197                                          shm->pages);
 198         } else {
 199                 struct kvec *kiov;
 200                 int i;
 201
 202                 kiov = kcalloc(num_pages, sizeof(*kiov), GFP_KERNEL);
 203                 if (!kiov) {
 204                         ret = ERR_PTR(-ENOMEM);
 205                         goto err;
 206                 }
 207
 208                 for (i = 0; i < num_pages; i++) {
 209                         kiov[i].iov_base = (void *)(start + i * PAGE_SIZE);
 210                         kiov[i].iov_len = PAGE_SIZE;
 211                 }
 212
 213                 rc = get_kernel_pages(kiov, num_pages, 0, shm->pages);
 214                 kfree(kiov);
 215         }
 216         if (rc > 0)
 217                 shm->num_pages = rc;
 218         if (rc != num_pages) {
 219                 if (rc >= 0)
 220                         rc = -ENOMEM;
 221                 ret = ERR_PTR(rc);
 222                 goto err;
 223         }
 224
 225         mutex_lock(&teedev->mutex);
 226         shm->id = idr_alloc(&teedev->idr, shm, 1, 0, GFP_KERNEL);
 227         mutex_unlock(&teedev->mutex);
 228
 229         if (shm->id < 0) {
 230                 ret = ERR_PTR(shm->id);
 231                 goto err;
 232         }
 233
 234         rc = teedev->desc->ops->shm_register(ctx, shm, shm->pages,
 235                                              shm->num_pages, start);
 236         if (rc) {
 237                 ret = ERR_PTR(rc);
 238                 goto err;
 239         }
 240
 241         return shm;
 242 err:
 243         if (shm) {
 244                 if (shm->id >= 0) {
 245                         mutex_lock(&teedev->mutex);
 246                         idr_remove(&teedev->idr, shm->id);
 247                         mutex_unlock(&teedev->mutex);
 248                 }
 249                 release_registered_pages(shm);
 250         }
 251         kfree(shm);
 252         teedev_ctx_put(ctx);
 253         tee_device_put(teedev);
 254         return ret;
 255 }
 256 EXPORT_SYMBOL_GPL(tee_shm_register);
 257
 258 static int tee_shm_fop_release(struct inode *inode, struct file *filp)
 259 {
 260         tee_shm_put(filp->private_data);
 261         return 0;
 262 }
 263
 264 static int tee_shm_fop_mmap(struct file *filp, struct vm_area_struct *vma)
 265 {
 266         struct tee_shm *shm = filp->private_data;
 267         size_t size = vma->vm_end - vma->vm_start;
 268
 269         /* Refuse sharing shared memory provided by application */
 270         if (shm->flags & TEE_SHM_USER_MAPPED)
 271                 return -EINVAL;
 272
 273         /* check for overflowing the buffer's size */
 274         if (vma->vm_pgoff + vma_pages(vma) > shm->size >> PAGE_SHIFT)
 275                 return -EINVAL;
 276
 277         return remap_pfn_range(vma, vma->vm_start, shm->paddr >> PAGE_SHIFT,
 278                                size, vma->vm_page_prot);
 279 }
 280
 281 static const struct file_operations tee_shm_fops = {
 282         .owner = THIS_MODULE,
 283         .release = tee_shm_fop_release,
 284         .mmap = tee_shm_fop_mmap,
 285 };
 286
 287 /**
 288  * tee_shm_get_fd() - Increase reference count and return file descriptor
 289  * @shm:        Shared memory handle
 290  * @returns user space file descriptor to shared memory
 291  */
 292 int tee_shm_get_fd(struct tee_shm *shm)
 293 {
 294         int fd;
 295
 296         if (!(shm->flags & TEE_SHM_DMA_BUF))
 297                 return -EINVAL;
 298
 299         /* matched by tee_shm_put() in tee_shm_op_release() */
 300         refcount_inc(&shm->refcount);
 301         fd = anon_inode_getfd("tee_shm", &tee_shm_fops, shm, O_RDWR);
 302         if (fd < 0)
 303                 tee_shm_put(shm);
 304         return fd;
 305 }
 306
 307 /**
 308  * tee_shm_free() - Free shared memory
 309  * @shm:        Handle to shared memory to free
 310  */
 311 void tee_shm_free(struct tee_shm *shm)
 312 {
 313         tee_shm_put(shm);
 314 }
 315 EXPORT_SYMBOL_GPL(tee_shm_free);
 316
 317 /**
 318  * tee_shm_va2pa() - Get physical address of a virtual address
 319  * @shm:        Shared memory handle
 320  * @va:         Virtual address to tranlsate
 321  * @pa:         Returned physical address
 322  * @returns 0 on success and < 0 on failure
 323  */
 324 int tee_shm_va2pa(struct tee_shm *shm, void *va, phys_addr_t *pa)
 325 {
 326         if (!(shm->flags & TEE_SHM_MAPPED))
 327                 return -EINVAL;
 328         /* Check that we're in the range of the shm */
 329         if ((char *)va < (char *)shm->kaddr)
 330                 return -EINVAL;
 331         if ((char *)va >= ((char *)shm->kaddr + shm->size))
 332                 return -EINVAL;
 333
 334         return tee_shm_get_pa(
 335                         shm, (unsigned long)va - (unsigned long)shm->kaddr, pa);
 336 }
 337 EXPORT_SYMBOL_GPL(tee_shm_va2pa);
 338
 339 /**
 340  * tee_shm_pa2va() - Get virtual address of a physical address
 341  * @shm:        Shared memory handle
 342  * @pa:         Physical address to tranlsate
 343  * @va:         Returned virtual address
 344  * @returns 0 on success and < 0 on failure
 345  */
 346 int tee_shm_pa2va(struct tee_shm *shm, phys_addr_t pa, void **va)
 347 {
 348         if (!(shm->flags & TEE_SHM_MAPPED))
 349                 return -EINVAL;
 350         /* Check that we're in the range of the shm */
 351         if (pa < shm->paddr)
 352                 return -EINVAL;
 353         if (pa >= (shm->paddr + shm->size))
 354                 return -EINVAL;
 355
 356         if (va) {
 357                 void *v = tee_shm_get_va(shm, pa - shm->paddr);
 358
 359                 if (IS_ERR(v))
 360                         return PTR_ERR(v);
 361                 *va = v;
 362         }
 363         return 0;
 364 }
 365 EXPORT_SYMBOL_GPL(tee_shm_pa2va);
 366
 367 /**
 368  * tee_shm_get_va() - Get virtual address of a shared memory plus an offset
 369  * @shm:        Shared memory handle
 370  * @offs:       Offset from start of this shared memory
 371  * @returns virtual address of the shared memory + offs if offs is within
 372  *      the bounds of this shared memory, else an ERR_PTR
 373  */
 374 void *tee_shm_get_va(struct tee_shm *shm, size_t offs)
 375 {
 376         if (!(shm->flags & TEE_SHM_MAPPED))
 377                 return ERR_PTR(-EINVAL);
 378         if (offs >= shm->size)
 379                 return ERR_PTR(-EINVAL);
 380         return (char *)shm->kaddr + offs;
 381 }
 382 EXPORT_SYMBOL_GPL(tee_shm_get_va);
 383
 384 /**
 385  * tee_shm_get_pa() - Get physical address of a shared memory plus an offset
 386  * @shm:        Shared memory handle
 387  * @offs:       Offset from start of this shared memory
 388  * @pa:         Physical address to return
 389  * @returns 0 if offs is within the bounds of this shared memory, else an
 390  *      error code.
 391  */
 392 int tee_shm_get_pa(struct tee_shm *shm, size_t offs, phys_addr_t *pa)
 393 {
 394         if (offs >= shm->size)
 395                 return -EINVAL;
 396         if (pa)
 397                 *pa = shm->paddr + offs;
 398         return 0;
 399 }
 400 EXPORT_SYMBOL_GPL(tee_shm_get_pa);
 401
 402 /**
 403  * tee_shm_get_from_id() - Find shared memory object and increase reference
 404  * count
 405  * @ctx:        Context owning the shared memory
 406  * @id:         Id of shared memory object
 407  * @returns a pointer to 'struct tee_shm' on success or an ERR_PTR on failure
 408  */
 409 struct tee_shm *tee_shm_get_from_id(struct tee_context *ctx, int id)
 410 {
 411         struct tee_device *teedev;
 412         struct tee_shm *shm;
 413
 414         if (!ctx)
 415                 return ERR_PTR(-EINVAL);
 416
 417         teedev = ctx->teedev;
 418         mutex_lock(&teedev->mutex);
 419         shm = idr_find(&teedev->idr, id);
 420         /*
 421          * If the tee_shm was found in the IDR it must have a refcount
 422          * larger than 0 due to the guarantee in tee_shm_put() below. So
 423          * it's safe to use refcount_inc().
 424          */
 425         if (!shm || shm->ctx != ctx)
 426                 shm = ERR_PTR(-EINVAL);
 427         else
 428                 refcount_inc(&shm->refcount);
 429         mutex_unlock(&teedev->mutex);
 430         return shm;
 431 }
 432 EXPORT_SYMBOL_GPL(tee_shm_get_from_id);
 433
 434 /**
 435  * tee_shm_put() - Decrease reference count on a shared memory handle
 436  * @shm:        Shared memory handle
 437  */
 438 void tee_shm_put(struct tee_shm *shm)
 439 {
 440         struct tee_device *teedev = shm->ctx->teedev;
 441         bool do_release = false;
 442
 443         mutex_lock(&teedev->mutex);
 444         if (refcount_dec_and_test(&shm->refcount)) {
 445                 /*
 446                  * refcount has reached 0, we must now remove it from the
 447                  * IDR before releasing the mutex. This will guarantee that
 448                  * the refcount_inc() in tee_shm_get_from_id() never starts
 449                  * from 0.
 450                  */
 451                 if (shm->flags & TEE_SHM_DMA_BUF)
 452                         idr_remove(&teedev->idr, shm->id);
 453                 do_release = true;
 454         }
 455         mutex_unlock(&teedev->mutex);
 456
 457         if (do_release)
 458                 tee_shm_release(teedev, shm);
 459 }
 460 EXPORT_SYMBOL_GPL(tee_shm_put);