tee: optee: add registered buffers handling into RPC calls

With latest changes to OP-TEE we can use any buffers as a shared memory.
Thus, it is possible for supplicant to provide part of own memory
when OP-TEE asks to allocate a shared buffer.

This patch adds support for such feature into RPC handling code.
Now when OP-TEE asks supplicant to allocate shared buffer, supplicant
can use TEE_IOC_SHM_REGISTER to provide such buffer. RPC handler is
aware of this, so it will pass list of allocated pages to OP-TEE.

Signed-off-by: Volodymyr Babchuk <vlad.babchuk@gmail.com>
[jw: fix parenthesis alignment in free_pages_list()]
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

4 files changed, 102 insertions, 11 deletions

diff --git a/drivers/tee/optee/call.c b/drivers/tee/optee/call.c
index a05e9e61105f..e675e82ff095 100644
--- a/drivers/tee/optee/call.c
+++ b/drivers/tee/optee/call.c
@@ -136,6 +136,7 @@ u32 optee_do_call_with_arg(struct tee_context *ctx, phys_addr_t parg)
         struct optee *optee = tee_get_drvdata(ctx->teedev);
         struct optee_call_waiter w;
         struct optee_rpc_param param = { };
+        struct optee_call_ctx call_ctx = { };
         u32 ret;
 
         param.a0 = OPTEE_SMC_CALL_WITH_ARG;
@@ -160,13 +161,14 @@ u32 optee_do_call_with_arg(struct tee_context *ctx, phys_addr_t parg)
                         param.a1 = res.a1;
                         param.a2 = res.a2;
                         param.a3 = res.a3;
-                        optee_handle_rpc(ctx, &param);
+                        optee_handle_rpc(ctx, &param, &call_ctx);
                 } else {
                         ret = res.a0;
                         break;
                 }
         }
 
+        optee_rpc_finalize_call(&call_ctx);
         /*
          * We're done with our thread in secure world, if there's any
          * thread waiters wake up one.
@@ -602,3 +604,18 @@ int optee_shm_unregister(struct tee_context *ctx, struct tee_shm *shm)
         tee_shm_free(shm_arg);
         return rc;
 }
+
+int optee_shm_register_supp(struct tee_context *ctx, struct tee_shm *shm,
+                            struct page **pages, size_t num_pages)
+{
+        /*
+         * We don't want to register supplicant memory in OP-TEE.
+         * Instead information about it will be passed in RPC code.
+         */
+        return 0;
+}
+
+int optee_shm_unregister_supp(struct tee_context *ctx, struct tee_shm *shm)
+{
+        return 0;
+}
diff --git a/drivers/tee/optee/core.c b/drivers/tee/optee/core.c
index 494ad0a23403..ef8e35e4ad88 100644
--- a/drivers/tee/optee/core.c
+++ b/drivers/tee/optee/core.c
@@ -331,6 +331,8 @@ static const struct tee_driver_ops optee_supp_ops = {
         .release = optee_release,
         .supp_recv = optee_supp_recv,
         .supp_send = optee_supp_send,
+        .shm_register = optee_shm_register_supp,
+        .shm_unregister = optee_shm_unregister_supp,
 };
 
 static const struct tee_desc optee_supp_desc = {
diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h
index d7bc77d95022..61a0052f6a54 100644
--- a/drivers/tee/optee/optee_private.h
+++ b/drivers/tee/optee/optee_private.h
@@ -130,7 +130,16 @@ struct optee_rpc_param {
         u32     a7;
 };
 
-void optee_handle_rpc(struct tee_context *ctx, struct optee_rpc_param *param);
+/* Holds context that is preserved during one STD call */
+struct optee_call_ctx {
+        /* information about pages list used in last allocation */
+        void *pages_list;
+        size_t num_entries;
+};
+
+void optee_handle_rpc(struct tee_context *ctx, struct optee_rpc_param *param,
+                      struct optee_call_ctx *call_ctx);
+void optee_rpc_finalize_call(struct optee_call_ctx *call_ctx);
 
 void optee_wait_queue_init(struct optee_wait_queue *wq);
 void optee_wait_queue_exit(struct optee_wait_queue *wq);
@@ -164,6 +173,10 @@ int optee_shm_register(struct tee_context *ctx, struct tee_shm *shm,
                        struct page **pages, size_t num_pages);
 int optee_shm_unregister(struct tee_context *ctx, struct tee_shm *shm);
 
+int optee_shm_register_supp(struct tee_context *ctx, struct tee_shm *shm,
+                            struct page **pages, size_t num_pages);
+int optee_shm_unregister_supp(struct tee_context *ctx, struct tee_shm *shm);
+
 int optee_from_msg_param(struct tee_param *params, size_t num_params,
                          const struct optee_msg_param *msg_params);
 int optee_to_msg_param(struct optee_msg_param *msg_params, size_t num_params,
diff --git a/drivers/tee/optee/rpc.c b/drivers/tee/optee/rpc.c
index cef417f4f4d2..690e48a61aca 100644
--- a/drivers/tee/optee/rpc.c
+++ b/drivers/tee/optee/rpc.c
@@ -200,7 +200,8 @@ static struct tee_shm *cmd_alloc_suppl(struct tee_context *ctx, size_t sz)
 }
 
 static void handle_rpc_func_cmd_shm_alloc(struct tee_context *ctx,
-                                          struct optee_msg_arg *arg)
+                                          struct optee_msg_arg *arg,
+                                          struct optee_call_ctx *call_ctx)
 {
         phys_addr_t pa;
         struct tee_shm *shm;
@@ -245,10 +246,49 @@ static void handle_rpc_func_cmd_shm_alloc(struct tee_context *ctx,
                 goto bad;
         }
 
-        arg->params[0].attr = OPTEE_MSG_ATTR_TYPE_TMEM_OUTPUT;
-        arg->params[0].u.tmem.buf_ptr = pa;
-        arg->params[0].u.tmem.size = sz;
-        arg->params[0].u.tmem.shm_ref = (unsigned long)shm;
+        sz = tee_shm_get_size(shm);
+
+        if (tee_shm_is_registered(shm)) {
+                struct page **pages;
+                u64 *pages_list;
+                size_t page_num;
+
+                pages = tee_shm_get_pages(shm, &page_num);
+                if (!pages || !page_num) {
+                        arg->ret = TEEC_ERROR_OUT_OF_MEMORY;
+                        goto bad;
+                }
+
+                pages_list = optee_allocate_pages_list(page_num);
+                if (!pages_list) {
+                        arg->ret = TEEC_ERROR_OUT_OF_MEMORY;
+                        goto bad;
+                }
+
+                call_ctx->pages_list = pages_list;
+                call_ctx->num_entries = page_num;
+
+                arg->params[0].attr = OPTEE_MSG_ATTR_TYPE_TMEM_OUTPUT |
+                                      OPTEE_MSG_ATTR_NONCONTIG;
+                /*
+                 * In the least bits of u.tmem.buf_ptr we store buffer offset
+                 * from 4k page, as described in OP-TEE ABI.
+                 */
+                arg->params[0].u.tmem.buf_ptr = virt_to_phys(pages_list) |
+                        (tee_shm_get_page_offset(shm) &
+                         (OPTEE_MSG_NONCONTIG_PAGE_SIZE - 1));
+                arg->params[0].u.tmem.size = tee_shm_get_size(shm);
+                arg->params[0].u.tmem.shm_ref = (unsigned long)shm;
+
+                optee_fill_pages_list(pages_list, pages, page_num,
+                                      tee_shm_get_page_offset(shm));
+        } else {
+                arg->params[0].attr = OPTEE_MSG_ATTR_TYPE_TMEM_OUTPUT;
+                arg->params[0].u.tmem.buf_ptr = pa;
+                arg->params[0].u.tmem.size = sz;
+                arg->params[0].u.tmem.shm_ref = (unsigned long)shm;
+        }
+
         arg->ret = TEEC_SUCCESS;
         return;
 bad:
@@ -307,8 +347,24 @@ static void handle_rpc_func_cmd_shm_free(struct tee_context *ctx,
         arg->ret = TEEC_SUCCESS;
 }
 
+static void free_pages_list(struct optee_call_ctx *call_ctx)
+{
+        if (call_ctx->pages_list) {
+                optee_free_pages_list(call_ctx->pages_list,
+                                      call_ctx->num_entries);
+                call_ctx->pages_list = NULL;
+                call_ctx->num_entries = 0;
+        }
+}
+
+void optee_rpc_finalize_call(struct optee_call_ctx *call_ctx)
+{
+        free_pages_list(call_ctx);
+}
+
 static void handle_rpc_func_cmd(struct tee_context *ctx, struct optee *optee,
-                                struct tee_shm *shm)
+                                struct tee_shm *shm,
+                                struct optee_call_ctx *call_ctx)
 {
         struct optee_msg_arg *arg;
 
@@ -329,7 +385,8 @@ static void handle_rpc_func_cmd(struct tee_context *ctx, struct optee *optee,
                 handle_rpc_func_cmd_wait(arg);
                 break;
         case OPTEE_MSG_RPC_CMD_SHM_ALLOC:
-                handle_rpc_func_cmd_shm_alloc(ctx, arg);
+                free_pages_list(call_ctx);
+                handle_rpc_func_cmd_shm_alloc(ctx, arg, call_ctx);
                 break;
         case OPTEE_MSG_RPC_CMD_SHM_FREE:
                 handle_rpc_func_cmd_shm_free(ctx, arg);
@@ -343,10 +400,12 @@ static void handle_rpc_func_cmd(struct tee_context *ctx, struct optee *optee,
  * optee_handle_rpc() - handle RPC from secure world
  * @ctx:        context doing the RPC
  * @param:      value of registers for the RPC
+ * @call_ctx:   call context. Preserved during one OP-TEE invocation
  *
  * Result of RPC is written back into @param.
  */
-void optee_handle_rpc(struct tee_context *ctx, struct optee_rpc_param *param)
+void optee_handle_rpc(struct tee_context *ctx, struct optee_rpc_param *param,
+                      struct optee_call_ctx *call_ctx)
 {
         struct tee_device *teedev = ctx->teedev;
         struct optee *optee = tee_get_drvdata(teedev);
@@ -381,7 +440,7 @@ void optee_handle_rpc(struct tee_context *ctx, struct optee_rpc_param *param)
                 break;
         case OPTEE_SMC_RPC_FUNC_CMD:
                 shm = reg_pair_to_ptr(param->a1, param->a2);
-                handle_rpc_func_cmd(ctx, optee, shm);
+                handle_rpc_func_cmd(ctx, optee, shm, call_ctx);
                 break;
         default:
                 pr_warn("Unknown RPC func 0x%x\n",