[PATCH v2 2/4] optee: add OPTEE_SMC_CALL_WITH_RPC_ARG and OPTEE_SMC_CALL_WITH_REGD_ARG

From: Jens Wiklander
Date: Mon Mar 21 2022 - 09:04:06 EST

Adds OPTEE_SMC_CALL_WITH_RPC_ARG and OPTEE_SMC_CALL_WITH_REGD_ARG where
the struct optee_msg_arg to be used for RPC is appended in the memory
following the normal argument struct optee_msg_arg. This is an
optimization to avoid caching the RPC argument struct while still
maintaining similar performance as if it was cached.

OPTEE_SMC_CALL_WITH_REGD_ARG optimized one step further by using a
registered shared memory object instead. It's in other aspects identical
to OPTEE_SMC_CALL_WITH_RPC_ARG.

The presence of OPTEE_SMC_CALL_WITH_RPC_ARG and
OPTEE_SMC_CALL_WITH_REGD_ARG is indicated by the new
OPTEE_SMC_SEC_CAP_RPC_ARG bit returned by
OPTEE_SMC_EXCHANGE_CAPABILITIES. OPTEE_SMC_EXCHANGE_CAPABILITIES also
reports the number of arguments that the RPC argument struct must have
room for.

OPTEE_SMC_CALL_WITH_RPC_ARG and OPTEE_SMC_CALL_WITH_ARG can be used
interleaved with difference that when OPTEE_SMC_CALL_WITH_RPC_ARG is
used the RPC argument struct to be used is the one appended to the
normal argument struct. The same is true for
OPTEE_SMC_CALL_WITH_REGD_ARG.

Signed-off-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx>
---
drivers/tee/optee/call.c | 2 +-
drivers/tee/optee/optee_smc.h | 47 ++++++++++++++---
drivers/tee/optee/smc_abi.c | 99 ++++++++++++++++++++++++++---------
3 files changed, 116 insertions(+), 32 deletions(-)

diff --git a/drivers/tee/optee/call.c b/drivers/tee/optee/call.c
index a9a237d20c61..58ac15c02818 100644
--- a/drivers/tee/optee/call.c
+++ b/drivers/tee/optee/call.c
@@ -130,7 +130,7 @@ struct tee_shm *optee_get_msg_arg(struct tee_context *ctx, size_t num_params,
return (void *)ma;
}

- memset(ma, 0, OPTEE_MSG_GET_ARG_SIZE(num_params));
+ memset(ma, 0, sz);
ma->num_params = num_params;
*msg_arg = ma;

diff --git a/drivers/tee/optee/optee_smc.h b/drivers/tee/optee/optee_smc.h
index d44a6ae994f8..378741a459b6 100644
--- a/drivers/tee/optee/optee_smc.h
+++ b/drivers/tee/optee/optee_smc.h
@@ -107,14 +107,22 @@ struct optee_smc_call_get_os_revision_result {
/*
* Call with struct optee_msg_arg as argument
*
- * When calling this function normal world has a few responsibilities:
+ * When called with OPTEE_SMC_CALL_WITH_RPC_ARG or
+ * OPTEE_SMC_CALL_WITH_REGD_ARG in a0 there is one RPC struct optee_msg_arg
+ * following after the first struct optee_msg_arg. The RPC struct
+ * optee_msg_arg has reserved space for the number of RPC parameters as
+ * returned by OPTEE_SMC_EXCHANGE_CAPABILITIES.
+ *
+ * When calling these functions normal world has a few responsibilities:
* 1. It must be able to handle eventual RPCs
* 2. Non-secure interrupts should not be masked
* 3. If asynchronous notifications has been negotiated successfully, then
- * asynchronous notifications should be unmasked during this call.
+ * the interrupt for asynchronous notifications should be unmasked
+ * during this call.
*
- * Call register usage:
- * a0 SMC Function ID, OPTEE_SMC*CALL_WITH_ARG
+ * Call register usage, OPTEE_SMC_CALL_WITH_ARG and
+ * OPTEE_SMC_CALL_WITH_RPC_ARG:
+ * a0 SMC Function ID, OPTEE_SMC_CALL_WITH_ARG or OPTEE_SMC_CALL_WITH_RPC_ARG
* a1 Upper 32 bits of a 64-bit physical pointer to a struct optee_msg_arg
* a2 Lower 32 bits of a 64-bit physical pointer to a struct optee_msg_arg
* a3 Cache settings, not used if physical pointer is in a predefined shared
@@ -122,6 +130,15 @@ struct optee_smc_call_get_os_revision_result {
* a4-6 Not used
* a7 Hypervisor Client ID register
*
+ * Call register usage, OPTEE_SMC_CALL_WITH_REGD_ARG:
+ * a0 SMC Function ID, OPTEE_SMC_CALL_WITH_REGD_ARG
+ * a1 Upper 32 bits of a 64-bit shared memory cookie
+ * a2 Lower 32 bits of a 64-bit shared memory cookie
+ * a3 Offset of the struct optee_msg_arg in the shared memory with the
+ * supplied cookie
+ * a4-6 Not used
+ * a7 Hypervisor Client ID register
+ *
* Normal return register usage:
* a0 Return value, OPTEE_SMC_RETURN_*
* a1-3 Not used
@@ -154,6 +171,10 @@ struct optee_smc_call_get_os_revision_result {
#define OPTEE_SMC_FUNCID_CALL_WITH_ARG OPTEE_MSG_FUNCID_CALL_WITH_ARG
#define OPTEE_SMC_CALL_WITH_ARG \
OPTEE_SMC_STD_CALL_VAL(OPTEE_SMC_FUNCID_CALL_WITH_ARG)
+#define OPTEE_SMC_CALL_WITH_RPC_ARG \
+ OPTEE_SMC_STD_CALL_VAL(OPTEE_SMC_FUNCID_CALL_WITH_RPC_ARG)
+#define OPTEE_SMC_CALL_WITH_REGD_ARG \
+ OPTEE_SMC_STD_CALL_VAL(OPTEE_SMC_FUNCID_CALL_WITH_REGD_ARG)

/*
* Get Shared Memory Config
@@ -202,6 +223,10 @@ struct optee_smc_get_shm_config_result {
* a0 OPTEE_SMC_RETURN_OK
* a1 bitfield of secure world capabilities OPTEE_SMC_SEC_CAP_*
* a2 The maximum secure world notification number
+ * a3 Bit[7:0]: Number of parameters needed for RPC to be supplied
+ * as the second MSG arg struct for
+ * OPTEE_SMC_CALL_WITH_ARG
+ * Bit[31:8]: Reserved (MBZ)
* a3-7 Preserved
*
* Error return register usage:
@@ -215,7 +240,6 @@ struct optee_smc_get_shm_config_result {
#define OPTEE_SMC_SEC_CAP_HAVE_RESERVED_SHM BIT(0)
/* Secure world can communicate via previously unregistered shared memory */
#define OPTEE_SMC_SEC_CAP_UNREGISTERED_SHM BIT(1)
-
/*
* Secure world supports commands "register/unregister shared memory",
* secure world accepts command buffers located in any parts of non-secure RAM
@@ -227,6 +251,8 @@ struct optee_smc_get_shm_config_result {
#define OPTEE_SMC_SEC_CAP_MEMREF_NULL BIT(4)
/* Secure world supports asynchronous notification of normal world */
#define OPTEE_SMC_SEC_CAP_ASYNC_NOTIF BIT(5)
+/* Secure world supports pre-allocating RPC arg struct */
+#define OPTEE_SMC_SEC_CAP_RPC_ARG BIT(6)

#define OPTEE_SMC_FUNCID_EXCHANGE_CAPABILITIES 9
#define OPTEE_SMC_EXCHANGE_CAPABILITIES \
@@ -236,7 +262,7 @@ struct optee_smc_exchange_capabilities_result {
unsigned long status;
unsigned long capabilities;
unsigned long max_notif_value;
- unsigned long reserved0;
+ unsigned long data;
};

/*
@@ -358,6 +384,9 @@ struct optee_smc_disable_shm_cache_result {
* should be called until all pended values have been retrieved. When a
* value is retrieved, it's cleared from the record in secure world.
*
+ * It is expected that this function is called from an interrupt handler
+ * in normal world.
+ *
* Call requests usage:
* a0 SMC Function ID, OPTEE_SMC_GET_ASYNC_NOTIF_VALUE
* a1-6 Not used
@@ -390,6 +419,12 @@ struct optee_smc_disable_shm_cache_result {
#define OPTEE_SMC_GET_ASYNC_NOTIF_VALUE \
OPTEE_SMC_FAST_CALL_VAL(OPTEE_SMC_FUNCID_GET_ASYNC_NOTIF_VALUE)

+/* See OPTEE_SMC_CALL_WITH_RPC_ARG above */
+#define OPTEE_SMC_FUNCID_CALL_WITH_RPC_ARG 18
+
+/* See OPTEE_SMC_CALL_WITH_REGD_ARG above */
+#define OPTEE_SMC_FUNCID_CALL_WITH_REGD_ARG 19
+
/*
* Resume from RPC (for example after processing a foreign interrupt)
*
diff --git a/drivers/tee/optee/smc_abi.c b/drivers/tee/optee/smc_abi.c
index 67b7f7d2ff27..b258d7306042 100644
--- a/drivers/tee/optee/smc_abi.c
+++ b/drivers/tee/optee/smc_abi.c
@@ -732,16 +732,9 @@ static void optee_rpc_finalize_call(struct optee_call_ctx *call_ctx)
}

static void handle_rpc_func_cmd(struct tee_context *ctx, struct optee *optee,
- struct tee_shm *shm,
+ struct optee_msg_arg *arg,
struct optee_call_ctx *call_ctx)
{
- struct optee_msg_arg *arg;
-
- arg = tee_shm_get_va(shm, 0);
- if (IS_ERR(arg)) {
- pr_err("%s: tee_shm_get_va %p failed\n", __func__, shm);
- return;
- }

switch (arg->cmd) {
case OPTEE_RPC_CMD_SHM_ALLOC:
@@ -765,11 +758,13 @@ static void handle_rpc_func_cmd(struct tee_context *ctx, struct optee *optee,
* Result of RPC is written back into @param.
*/
static void optee_handle_rpc(struct tee_context *ctx,
+ struct optee_msg_arg *rpc_arg,
struct optee_rpc_param *param,
struct optee_call_ctx *call_ctx)
{
struct tee_device *teedev = ctx->teedev;
struct optee *optee = tee_get_drvdata(teedev);
+ struct optee_msg_arg *arg;
struct tee_shm *shm;
phys_addr_t pa;

@@ -801,8 +796,19 @@ static void optee_handle_rpc(struct tee_context *ctx,
*/
break;
case OPTEE_SMC_RPC_FUNC_CMD:
- shm = reg_pair_to_ptr(param->a1, param->a2);
- handle_rpc_func_cmd(ctx, optee, shm, call_ctx);
+ if (rpc_arg) {
+ arg = rpc_arg;
+ } else {
+ shm = reg_pair_to_ptr(param->a1, param->a2);
+ arg = tee_shm_get_va(shm, 0);
+ if (IS_ERR(arg)) {
+ pr_err("%s: tee_shm_get_va %p failed\n",
+ __func__, shm);
+ break;
+ }
+ }
+
+ handle_rpc_func_cmd(ctx, optee, arg, call_ctx);
break;
default:
pr_warn("Unknown RPC func 0x%x\n",
@@ -816,7 +822,7 @@ static void optee_handle_rpc(struct tee_context *ctx,
/**
* optee_smc_do_call_with_arg() - Do an SMC to OP-TEE in secure world
* @ctx: calling context
- * @arg: shared memory holding the message to pass to secure world
+ * @shm: shared memory holding the message to pass to secure world
*
* Does and SMC to OP-TEE in secure world and handles eventual resulting
* Remote Procedure Calls (RPC) from OP-TEE.
@@ -824,21 +830,46 @@ static void optee_handle_rpc(struct tee_context *ctx,
* Returns return code from secure world, 0 is OK
*/
static int optee_smc_do_call_with_arg(struct tee_context *ctx,
- struct tee_shm *arg)
+ struct tee_shm *shm)
{
struct optee *optee = tee_get_drvdata(ctx->teedev);
struct optee_call_waiter w;
struct optee_rpc_param param = { };
struct optee_call_ctx call_ctx = { };
- phys_addr_t parg;
+ struct optee_msg_arg *rpc_arg = NULL;
int rc;

- rc = tee_shm_get_pa(arg, 0, &parg);
- if (rc)
- return rc;
+ if (optee->rpc_param_count) {
+ struct optee_msg_arg *arg;
+ unsigned int rpc_arg_offs;
+
+ arg = tee_shm_get_va(shm, 0);
+ if (IS_ERR(arg))
+ return PTR_ERR(arg);

- param.a0 = OPTEE_SMC_CALL_WITH_ARG;
- reg_pair_from_64(&param.a1, &param.a2, parg);
+ rpc_arg_offs = OPTEE_MSG_GET_ARG_SIZE(arg->num_params);
+ rpc_arg = tee_shm_get_va(shm, rpc_arg_offs);
+ if (IS_ERR(arg))
+ return PTR_ERR(arg);
+ }
+
+ if (rpc_arg && tee_shm_is_dynamic(shm)) {
+ param.a0 = OPTEE_SMC_CALL_WITH_REGD_ARG;
+ reg_pair_from_64(&param.a1, &param.a2, (u_long)shm);
+ param.a3 = 0;
+ } else {
+ phys_addr_t parg;
+
+ rc = tee_shm_get_pa(shm, 0, &parg);
+ if (rc)
+ return rc;
+
+ if (rpc_arg)
+ param.a0 = OPTEE_SMC_CALL_WITH_RPC_ARG;
+ else
+ param.a0 = OPTEE_SMC_CALL_WITH_ARG;
+ reg_pair_from_64(&param.a1, &param.a2, parg);
+ }
/* Initialize waiter */
optee_cq_wait_init(&optee->call_queue, &w);
while (true) {
@@ -862,7 +893,7 @@ static int optee_smc_do_call_with_arg(struct tee_context *ctx,
param.a1 = res.a1;
param.a2 = res.a2;
param.a3 = res.a3;
- optee_handle_rpc(ctx, &param, &call_ctx);
+ optee_handle_rpc(ctx, rpc_arg, &param, &call_ctx);
} else {
rc = res.a0;
break;
@@ -1118,7 +1149,8 @@ static bool optee_msg_api_revision_is_compatible(optee_invoke_fn *invoke_fn)
}

static bool optee_msg_exchange_capabilities(optee_invoke_fn *invoke_fn,
- u32 *sec_caps, u32 *max_notif_value)
+ u32 *sec_caps, u32 *max_notif_value,
+ unsigned int *rpc_param_count)
{
union {
struct arm_smccc_res smccc;
@@ -1145,6 +1177,10 @@ static bool optee_msg_exchange_capabilities(optee_invoke_fn *invoke_fn,
*max_notif_value = res.result.max_notif_value;
else
*max_notif_value = OPTEE_DEFAULT_MAX_NOTIF_VALUE;
+ if (*sec_caps & OPTEE_SMC_SEC_CAP_RPC_ARG)
+ *rpc_param_count = (u8)res.result.data;
+ else
+ *rpc_param_count = 0;

return true;
}
@@ -1251,7 +1287,8 @@ static int optee_smc_remove(struct platform_device *pdev)
* reference counters and also avoid wild pointers in secure world
* into the old shared memory range.
*/
- optee_disable_shm_cache(optee);
+ if (!optee->rpc_param_count)
+ optee_disable_shm_cache(optee);

optee_smc_notif_uninit_irq(optee);

@@ -1274,7 +1311,10 @@ static int optee_smc_remove(struct platform_device *pdev)
*/
static void optee_shutdown(struct platform_device *pdev)
{
- optee_disable_shm_cache(platform_get_drvdata(pdev));
+ struct optee *optee = platform_get_drvdata(pdev);
+
+ if (!optee->rpc_param_count)
+ optee_disable_shm_cache(optee);
}

static int optee_probe(struct platform_device *pdev)
@@ -1283,6 +1323,7 @@ static int optee_probe(struct platform_device *pdev)
struct tee_shm_pool *pool = ERR_PTR(-EINVAL);
struct optee *optee = NULL;
void *memremaped_shm = NULL;
+ unsigned int rpc_param_count;
struct tee_device *teedev;
struct tee_context *ctx;
u32 max_notif_value;
@@ -1306,7 +1347,8 @@ static int optee_probe(struct platform_device *pdev)
}

if (!optee_msg_exchange_capabilities(invoke_fn, &sec_caps,
- &max_notif_value)) {
+ &max_notif_value,
+ &rpc_param_count)) {
pr_warn("capabilities mismatch\n");
return -EINVAL;
}
@@ -1335,6 +1377,7 @@ static int optee_probe(struct platform_device *pdev)
optee->ops = &optee_ops;
optee->smc.invoke_fn = invoke_fn;
optee->smc.sec_caps = sec_caps;
+ optee->rpc_param_count = rpc_param_count;

teedev = tee_device_alloc(&optee_clnt_desc, NULL, pool, optee);
if (IS_ERR(teedev)) {
@@ -1403,7 +1446,12 @@ static int optee_probe(struct platform_device *pdev)
*/
optee_disable_unmapped_shm_cache(optee);

- optee_enable_shm_cache(optee);
+ /*
+ * Only enable the shm cache in case we're not able to pass the RPC
+ * arg struct right after the normal arg struct.
+ */
+ if (!optee->rpc_param_count)
+ optee_enable_shm_cache(optee);

if (optee->smc.sec_caps & OPTEE_SMC_SEC_CAP_DYNAMIC_SHM)
pr_info("dynamic shared memory is enabled\n");
@@ -1416,7 +1464,8 @@ static int optee_probe(struct platform_device *pdev)
return 0;

err_disable_shm_cache:
- optee_disable_shm_cache(optee);
+ if (!optee->rpc_param_count)
+ optee_disable_shm_cache(optee);
optee_smc_notif_uninit_irq(optee);
optee_unregister_devices();
err_notif_uninit:
--
2.31.1