[PATCH v1 09/14] tee: optee: add registered buffers handling into RPC calls

From: Volodymyr Babchuk
Date: Fri Oct 13 2017 - 15:34:21 EST

From: Volodymyr Babchuk <vlad.babchuk@xxxxxxxxx>

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@xxxxxxxxx>
---

* free_pages_array() and friends were renamed to free_pages_list()

---
drivers/tee/optee/call.c | 19 +++++++++-
drivers/tee/optee/core.c | 2 +
drivers/tee/optee/optee_private.h | 15 +++++++-
drivers/tee/optee/rpc.c | 77 ++++++++++++++++++++++++++++++++++-----
4 files changed, 102 insertions(+), 11 deletions(-)

diff --git a/drivers/tee/optee/call.c b/drivers/tee/optee/call.c
index a22f5f0..ed5e82d 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 3729ebb..d22433c 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 d7bc77d..61a0052 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 cef417f..7bd18e3 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",
--
2.7.4