[PATCH v4 5/6] optee: FF-A: dynamic restricted memory allocation

Jens Wiklander
2024-12-17T10:07:41Z

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Add support in the OP-TEE backend driver dynamic restricted memory
allocation with FF-A.

The restricted memory pools for dynamically allocated restrict memory
are instantiated when requested by user-space. This instantiation can
fail if OP-TEE doesn't support the requested use-case of restricted
memory.

Restricted memory pools based on a static carveout or dynamic allocation
can coexist for different use-cases. We use only dynamic allocation with
FF-A.

Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
---
drivers/tee/optee/ffa_abi.c | 135 ++++++++++++-
drivers/tee/optee/optee_private.h | 10 +-
drivers/tee/optee/rstmem.c | 316 +++++++++++++++++++++++++++++-
3 files changed, 457 insertions(+), 4 deletions(-)

diff --git a/drivers/tee/optee/ffa_abi.c b/drivers/tee/optee/ffa_abi.c
index 02e6175ac5f0..f500cf101c8d 100644
--- a/drivers/tee/optee/ffa_abi.c
+++ b/drivers/tee/optee/ffa_abi.c
@@ -672,6 +672,122 @@ static int optee_ffa_do_call_with_arg(struct tee_context *ctx,
return optee_ffa_yielding_call(ctx, &data, rpc_arg, system_thread);
}

+static int do_call_lend_rstmem(struct optee *optee, u64 cookie, u32 use_case)
+{
+ struct optee_shm_arg_entry *entry;
+ struct optee_msg_arg *msg_arg;
+ struct tee_shm *shm;
+ u_int offs;
+ int rc;
+
+ msg_arg = optee_get_msg_arg(optee->ctx, 1, &entry, &shm, &offs);
+ if (IS_ERR(msg_arg))
+ return PTR_ERR(msg_arg);
+
+ msg_arg->cmd = OPTEE_MSG_CMD_ASSIGN_RSTMEM;
+ msg_arg->params[0].attr = OPTEE_MSG_ATTR_TYPE_VALUE_INPUT;
+ msg_arg->params[0].u.value.a = cookie;
+ msg_arg->params[0].u.value.b = use_case;
+
+ rc = optee->ops->do_call_with_arg(optee->ctx, shm, offs, false);
+ if (rc)
+ goto out;
+ if (msg_arg->ret != TEEC_SUCCESS) {
+ rc = -EINVAL;
+ goto out;
+ }
+
+out:
+ optee_free_msg_arg(optee->ctx, entry, offs);
+ return rc;
+}
+
+static int optee_ffa_lend_rstmem(struct optee *optee, struct tee_shm *rstmem,
+ u16 *end_points, unsigned int ep_count)
+{
+ struct ffa_device *ffa_dev = optee->ffa.ffa_dev;
+ const struct ffa_mem_ops *mem_ops = ffa_dev->ops->mem_ops;
+ const struct ffa_msg_ops *msg_ops = ffa_dev->ops->msg_ops;
+ struct ffa_send_direct_data data;
+ struct ffa_mem_region_attributes *mem_attr;
+ struct ffa_mem_ops_args args = {
+ .use_txbuf = true,
+ .tag = rstmem->use_case,
+ };
+ struct page *page;
+ struct scatterlist sgl;
+ unsigned int n;
+ int rc;
+
+ mem_attr = kcalloc(ep_count, sizeof(*mem_attr), GFP_KERNEL);
+ for (n = 0; n < ep_count; n++) {
+ mem_attr[n].receiver = end_points[n];
+ mem_attr[n].attrs = FFA_MEM_RW;
+ }
+ args.attrs = mem_attr;
+ args.nattrs = ep_count;
+
+ page = phys_to_page(rstmem->paddr);
+ sg_init_table(&sgl, 1);
+ sg_set_page(&sgl, page, rstmem->size, 0);
+
+ args.sg = &sgl;
+ rc = mem_ops->memory_lend(&args);
+ kfree(mem_attr);
+ if (rc)
+ return rc;
+
+ rc = do_call_lend_rstmem(optee, args.g_handle, rstmem->use_case);
+ if (rc)
+ goto err_reclaim;
+
+ rc = optee_shm_add_ffa_handle(optee, rstmem, args.g_handle);
+ if (rc)
+ goto err_unreg;
+
+ rstmem->sec_world_id = args.g_handle;
+
+ return 0;
+
+err_unreg:
+ data = (struct ffa_send_direct_data){
+ .data0 = OPTEE_FFA_RELEASE_RSTMEM,
+ .data1 = (u32)args.g_handle,
+ .data2 = (u32)(args.g_handle >> 32),
+ };
+ msg_ops->sync_send_receive(ffa_dev, &data);
+err_reclaim:
+ mem_ops->memory_reclaim(args.g_handle, 0);
+ return rc;
+}
+
+static int optee_ffa_reclaim_rstmem(struct optee *optee, struct tee_shm *rstmem)
+{
+ struct ffa_device *ffa_dev = optee->ffa.ffa_dev;
+ const struct ffa_msg_ops *msg_ops = ffa_dev->ops->msg_ops;
+ const struct ffa_mem_ops *mem_ops = ffa_dev->ops->mem_ops;
+ u64 global_handle = rstmem->sec_world_id;
+ struct ffa_send_direct_data data = {
+ .data0 = OPTEE_FFA_RELEASE_RSTMEM,
+ .data1 = (u32)global_handle,
+ .data2 = (u32)(global_handle >> 32)
+ };
+ int rc;
+
+ optee_shm_rem_ffa_handle(optee, global_handle);
+ rstmem->sec_world_id = 0;
+
+ rc = msg_ops->sync_send_receive(ffa_dev, &data);
+ if (rc)
+ pr_err("Release SHM id 0x%llx rc %d\n", global_handle, rc);
+
+ rc = mem_ops->memory_reclaim(global_handle, 0);
+ if (rc)
+ pr_err("mem_reclaim: 0x%llx %d", global_handle, rc);
+
+ return rc;
+}
+
/*
* 6. Driver initialization
*
@@ -785,7 +901,10 @@ static void optee_ffa_get_version(struct tee_device *teedev,
.gen_caps = TEE_GEN_CAP_GP | TEE_GEN_CAP_REG_MEM |
TEE_GEN_CAP_MEMREF_NULL,
};
+ struct optee *optee = tee_get_drvdata(teedev);

+ if (optee->rstmem_pools)
+ v.gen_caps |= TEE_GEN_CAP_RSTMEM;
*vers = v;
}

@@ -804,6 +923,8 @@ static const struct tee_driver_ops optee_ffa_clnt_ops = {
.cancel_req = optee_cancel_req,
.shm_register = optee_ffa_shm_register,
.shm_unregister = optee_ffa_shm_unregister,
+ .rstmem_alloc = optee_rstmem_alloc,
+ .rstmem_free = optee_rstmem_free,
};

static const struct tee_desc optee_ffa_clnt_desc = {
@@ -820,6 +941,8 @@ static const struct tee_driver_ops optee_ffa_supp_ops = {
.supp_send = optee_supp_send,
.shm_register = optee_ffa_shm_register, /* same as for clnt ops */
.shm_unregister = optee_ffa_shm_unregister_supp,
+ .rstmem_alloc = optee_rstmem_alloc,
+ .rstmem_free = optee_rstmem_free,
};

static const struct tee_desc optee_ffa_supp_desc = {
@@ -833,6 +956,8 @@ static const struct optee_ops optee_ffa_ops = {
.do_call_with_arg = optee_ffa_do_call_with_arg,
.to_msg_param = optee_ffa_to_msg_param,
.from_msg_param = optee_ffa_from_msg_param,
+ .lend_rstmem = optee_ffa_lend_rstmem,
+ .reclaim_rstmem = optee_ffa_reclaim_rstmem,
};

static void optee_ffa_remove(struct ffa_device *ffa_dev)
@@ -937,11 +1062,17 @@ static int optee_ffa_probe(struct ffa_device *ffa_dev)
(sec_caps & OPTEE_FFA_SEC_CAP_RPMB_PROBE))
optee->in_kernel_rpmb_routing = true;

+ if (sec_caps & OPTEE_FFA_SEC_CAP_RSTMEM) {
+ rc = optee_rstmem_pools_init(optee);
+ if (rc)
+ goto err_free_pool;
+ }
+
teedev = tee_device_alloc(&optee_ffa_clnt_desc, NULL, optee->pool,
optee);
if (IS_ERR(teedev)) {
rc = PTR_ERR(teedev);
- goto err_free_pool;
+ goto err_free_rstmem_pools;
}
optee->teedev = teedev;

@@ -1020,6 +1151,8 @@ static int optee_ffa_probe(struct ffa_device *ffa_dev)
tee_device_unregister(optee->teedev);
err_free_pool:
tee_shm_pool_free(pool);
+err_free_rstmem_pools:
+ optee_rstmem_pools_uninit(optee);
err_free_optee:
kfree(optee);
return rc;
diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h
index 0491889e5b0e..dd2a3a2224bc 100644
--- a/drivers/tee/optee/optee_private.h
+++ b/drivers/tee/optee/optee_private.h
@@ -174,9 +174,14 @@ struct optee;
* @do_call_with_arg: enters OP-TEE in secure world
* @to_msg_param: converts from struct tee_param to OPTEE_MSG parameters
* @from_msg_param: converts from OPTEE_MSG parameters to struct tee_param
+ * @lend_rstmem: lends physically contiguous memory as restricted
+ * memory, inaccessible by the kernel
+ * @reclaim_rstmem: reclaims restricted memory previously lent with
+ * @lend_rstmem() and makes it accessible by the
+ * kernel again
*
* These OPs are only supposed to be used internally in the OP-TEE driver
- * as a way of abstracting the different methogs of entering OP-TEE in
+ * as a way of abstracting the different methods of entering OP-TEE in
* secure world.
*/
struct optee_ops {
@@ -191,6 +196,9 @@ struct optee_ops {
size_t num_params,
const struct optee_msg_param *msg_params,
bool update_out);
+ int (*lend_rstmem)(struct optee *optee, struct tee_shm *rstmem,
+ u16 *end_points, unsigned int ep_count);
+ int (*reclaim_rstmem)(struct optee *optee, struct tee_shm *rstmem);
};

/**
diff --git a/drivers/tee/optee/rstmem.c b/drivers/tee/optee/rstmem.c
index 01456bc3e2f6..8c561d638733 100644
--- a/drivers/tee/optee/rstmem.c
+++ b/drivers/tee/optee/rstmem.c
@@ -4,6 +4,7 @@
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

+#include <linux/cma.h>
#include <linux/dma-map-ops.h>
#include <linux/errno.h>
#include <linux/genalloc.h>
@@ -13,11 +14,313 @@
#include <linux/types.h>
#include "optee_private.h"

+#ifdef CONFIG_CMA
+struct optee_rstmem_cma_pool {
+ struct tee_shm_pool pool;
+ struct page *page;
+ struct optee *optee;
+ size_t page_count;
+ u16 *end_points;
+ u_int end_point_count;
+ u_int align;
+ refcount_t refcount;
+ struct tee_shm rstmem;
+ /* Protects when initializing and tearing down this struct */
+ struct mutex mutex;
+};
+
+static struct optee_rstmem_cma_pool *
+to_rstmem_cma_pool(struct tee_shm_pool *pool)
+{
+ return container_of(pool, struct optee_rstmem_cma_pool, pool);
+}
+
+static int init_cma_rstmem(struct optee_rstmem_cma_pool *rp)
+{
+ struct cma *cma = dev_get_cma_area(&rp->optee->teedev->dev);
+ int rc;
+
+ rp->page = cma_alloc(cma, rp->page_count, rp->align, true/*no_warn*/);
+ if (!rp->page)
+ return -ENOMEM;
+
+ /*
+ * TODO unmap the memory range since the physical memory will
+ * become inaccesible after the lend_rstmem() call.
+ */
+
+ rp->rstmem.paddr = page_to_phys(rp->page);
+ rp->rstmem.size = rp->page_count * PAGE_SIZE;
+ rc = rp->optee->ops->lend_rstmem(rp->optee, &rp->rstmem,
+ rp->end_points, rp->end_point_count);
+ if (rc)
+ goto err_release;
+
+ rp->pool.private_data = gen_pool_create(PAGE_SHIFT, -1);
+ if (!rp->pool.private_data) {
+ rc = -ENOMEM;
+ goto err_reclaim;
+ }
+
+ rc = gen_pool_add(rp->pool.private_data, rp->rstmem.paddr,
+ rp->rstmem.size, -1);
+ if (rc)
+ goto err_free_pool;
+
+ refcount_set(&rp->refcount, 1);
+ return 0;
+
+err_free_pool:
+ gen_pool_destroy(rp->pool.private_data);
+err_reclaim:
+ rp->optee->ops->reclaim_rstmem(rp->optee, &rp->rstmem);
+err_release:
+ cma_release(cma, rp->page, rp->page_count);
+ rp->rstmem.paddr = 0;
+ rp->rstmem.size = 0;
+ rp->rstmem.sec_world_id = 0;
+ return rc;
+}
+
+static int get_cma_rstmem(struct optee_rstmem_cma_pool *rp)
+{
+ int rc = 0;
+
+ if (!refcount_inc_not_zero(&rp->refcount)) {
+ mutex_lock(&rp->mutex);
+ if (rp->pool.private_data) {
+ /*
+ * Another thread has already initialized the pool
+ * before us, or the pool was just about to be torn
+ * down. Either way we only need to increase the
+ * refcount and we're done.
+ */
+ refcount_inc(&rp->refcount);
+ } else {
+ rc = init_cma_rstmem(rp);
+ }
+ mutex_unlock(&rp->mutex);
+ }
+
+ return rc;
+}
+
+static void release_cma_rstmem(struct optee_rstmem_cma_pool *rp)
+{
+ gen_pool_destroy(rp->pool.private_data);
+ rp->optee->ops->reclaim_rstmem(rp->optee, &rp->rstmem);
+ cma_release(dev_get_cma_area(&rp->optee->teedev->dev), rp->page,
+ rp->page_count);
+
+ rp->pool.private_data = NULL;
+ rp->page = NULL;
+ rp->rstmem.paddr = 0;
+ rp->rstmem.size = 0;
+ rp->rstmem.sec_world_id = 0;
+}
+
+static void put_cma_rstmem(struct optee_rstmem_cma_pool *rp)
+{
+ if (refcount_dec_and_test(&rp->refcount)) {
+ mutex_lock(&rp->mutex);
+ if (rp->pool.private_data)
+ release_cma_rstmem(rp);
+ mutex_unlock(&rp->mutex);
+ }
+}
+
+static int rstmem_pool_op_cma_alloc(struct tee_shm_pool *pool,
+ struct tee_shm *shm, size_t size,
+ size_t align)
+{
+ struct optee_rstmem_cma_pool *rp = to_rstmem_cma_pool(pool);
+ size_t sz = ALIGN(size, PAGE_SIZE);
+ phys_addr_t pa;
+ int rc;
+
+ rc = get_cma_rstmem(rp);
+ if (rc)
+ return rc;
+
+ pa = gen_pool_alloc(rp->pool.private_data, sz);
+ if (!pa) {
+ put_cma_rstmem(rp);
+ return -ENOMEM;
+ }
+
+ shm->size = sz;
+ shm->paddr = pa;
+ shm->offset = pa - page_to_phys(rp->page);
+ shm->sec_world_id = rp->rstmem.sec_world_id;
+
+ return 0;
+}
+
+static void rstmem_pool_op_cma_free(struct tee_shm_pool *pool,
+ struct tee_shm *shm)
+{
+ struct optee_rstmem_cma_pool *rp = to_rstmem_cma_pool(pool);
+
+ gen_pool_free(rp->pool.private_data, shm->paddr, shm->size);
+ shm->size = 0;
+ shm->paddr = 0;
+ shm->offset = 0;
+ shm->sec_world_id = 0;
+ put_cma_rstmem(rp);
+}
+
+static void pool_op_cma_destroy_pool(struct tee_shm_pool *pool)
+{
+ struct optee_rstmem_cma_pool *rp = to_rstmem_cma_pool(pool);
+
+ mutex_destroy(&rp->mutex);
+ kfree(rp);
+}
+
+static struct tee_shm_pool_ops rstmem_pool_ops_cma = {
+ .alloc = rstmem_pool_op_cma_alloc,
+ .free = rstmem_pool_op_cma_free,
+ .destroy_pool = pool_op_cma_destroy_pool,
+};
+
+static int get_rstmem_config(struct optee *optee, u32 use_case,
+ size_t *min_size, u_int *min_align,
+ u16 *end_points, u_int *ep_count)
+{
+ struct tee_param params[2] = {
+ [0] = {
+ .attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT,
+ .u.value.a = use_case,
+ },
+ [1] = {
+ .attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT,
+ },
+ };
+ struct optee_shm_arg_entry *entry;
+ struct tee_shm *shm_param = NULL;
+ struct optee_msg_arg *msg_arg;
+ struct tee_shm *shm;
+ u_int offs;
+ int rc;
+
+ if (end_points && *ep_count) {
+ params[1].u.memref.size = *ep_count * sizeof(*end_points);
+ shm_param = tee_shm_alloc_priv_buf(optee->ctx,
+ params[1].u.memref.size);
+ if (IS_ERR(shm_param))
+ return PTR_ERR(shm_param);
+ params[1].u.memref.shm = shm_param;
+ }
+
+ msg_arg = optee_get_msg_arg(optee->ctx, ARRAY_SIZE(params), &entry,
+ &shm, &offs);
+ if (IS_ERR(msg_arg)) {
+ rc = PTR_ERR(msg_arg);
+ goto out_free_shm;
+ }
+ msg_arg->cmd = OPTEE_MSG_CMD_GET_RSTMEM_CONFIG;
+
+ rc = optee->ops->to_msg_param(optee, msg_arg->params,
+ ARRAY_SIZE(params), params,
+ false /*!update_out*/);
+ if (rc)
+ goto out_free_msg;
+
+ rc = optee->ops->do_call_with_arg(optee->ctx, shm, offs, false);
+ if (rc)
+ goto out_free_msg;
+ if (msg_arg->ret && msg_arg->ret != TEEC_ERROR_SHORT_BUFFER) {
+ rc = -EINVAL;
+ goto out_free_msg;
+ }
+
+ rc = optee->ops->from_msg_param(optee, params, ARRAY_SIZE(params),
+ msg_arg->params, true /*update_out*/);
+ if (rc)
+ goto out_free_msg;
+
+ if (!msg_arg->ret && end_points &&
+ *ep_count < params[1].u.memref.size / sizeof(u16)) {
+ rc = -EINVAL;
+ goto out_free_msg;
+ }
+
+ *min_size = params[0].u.value.a;
+ *min_align = params[0].u.value.b;
+ *ep_count = params[1].u.memref.size / sizeof(u16);
+
+ if (msg_arg->ret == TEEC_ERROR_SHORT_BUFFER) {
+ rc = -ENOSPC;
+ goto out_free_msg;
+ }
+
+ if (end_points)
+ memcpy(end_points, tee_shm_get_va(shm_param, 0),
+ params[1].u.memref.size);
+
+out_free_msg:
+ optee_free_msg_arg(optee->ctx, entry, offs);
+out_free_shm:
+ if (shm_param)
+ tee_shm_free(shm_param);
+ return rc;
+}
+
+static struct tee_shm_pool *alloc_rstmem_pool(struct optee *optee, u32 use_case)
+{
+ struct optee_rstmem_cma_pool *rp;
+ size_t min_size;
+ int rc;
+
+ rp = kzalloc(sizeof(*rp), GFP_KERNEL);
+ if (!rp)
+ return ERR_PTR(-ENOMEM);
+ rp->rstmem.use_case = use_case;
+
+ rc = get_rstmem_config(optee, use_case, &min_size, &rp->align, NULL,
+ &rp->end_point_count);
+ if (rc) {
+ if (rc != -ENOSPC)
+ goto err;
+ rp->end_points = kcalloc(rp->end_point_count,
+ sizeof(*rp->end_points), GFP_KERNEL);
+ if (!rp->end_points) {
+ rc = -ENOMEM;
+ goto err;
+ }
+ rc = get_rstmem_config(optee, use_case, &min_size, &rp->align,
+ rp->end_points, &rp->end_point_count);
+ if (rc)
+ goto err_kfree_eps;
+ }
+
+ rp->pool.ops = &rstmem_pool_ops_cma;
+ rp->optee = optee;
+ rp->page_count = min_size / PAGE_SIZE;
+ mutex_init(&rp->mutex);
+
+ return &rp->pool;
+
+err_kfree_eps:
+ kfree(rp->end_points);
+err:
+ kfree(rp);
+ return ERR_PTR(rc);
+}
+#else /*CONFIG_CMA*/
+static struct tee_shm_pool *alloc_rstmem_pool(struct optee *optee __unused,
+ u32 use_case __unused)
+{
+ return ERR_PTR(-EINVAL);
+}
+#endif /*CONFIG_CMA*/
+
int optee_rstmem_alloc(struct tee_context *ctx, struct tee_shm *shm,
u32 flags, u32 use_case, size_t size)
{
struct optee *optee = tee_get_drvdata(ctx->teedev);
struct tee_shm_pool *pool;
+ int rc;

if (!optee->rstmem_pools)
return -EINVAL;
@@ -25,8 +328,17 @@ int optee_rstmem_alloc(struct tee_context *ctx, struct tee_shm *shm,
return -EINVAL;

pool = xa_load(&optee->rstmem_pools->xa, use_case);
- if (!pool)
- return -EINVAL;
+ if (!pool) {
+ pool = alloc_rstmem_pool(optee, use_case);
+ if (IS_ERR(pool))
+ return PTR_ERR(pool);
+ rc = xa_insert(&optee->rstmem_pools->xa, use_case, pool,
+ GFP_KERNEL);
+ if (rc) {
+ pool->ops->destroy_pool(pool);
+ return rc;
+ }
+ }

return pool->ops->alloc(pool, shm, size, 0);
}
--
2.43.0