AArch32: Add API to invoke runtime service handler

This patch adds an API in runtime service framework to
invoke the registered handler corresponding to the SMC function
identifier. This is helpful for AArch32 because the number of
arguments required by the handler is more than registers
available as per AArch32 program calling conventions and
requires the use of stack. Hence this new API will do the
necessary argument setup and invoke the appropriate
handler. Although this API is primarily intended for AArch32,
it can be used for AArch64 as well.

Change-Id: Iefa15947fe5a1df55b0859886e677446a0fd7241

1 files changed, 28 insertions, 0 deletions

diff --git a/common/runtime_svc.c b/common/runtime_svc.c
index b8af6cd8..df0d64ca 100644
--- a/common/runtime_svc.c
+++ b/common/runtime_svc.c
@@ -52,6 +52,34 @@ static rt_svc_desc_t *rt_svc_descs;
 					/ sizeof(rt_svc_desc_t))
 
 /*******************************************************************************
+ * Function to invoke the registered `handle` corresponding to the smc_fid.
+ ******************************************************************************/
+uintptr_t handle_runtime_svc(uint32_t smc_fid,
+			     void *cookie,
+			     void *handle,
+			     unsigned int flags)
+{
+	u_register_t x1, x2, x3, x4;
+	int index, idx;
+	const rt_svc_desc_t *rt_svc_descs;
+
+	assert(handle);
+	idx = get_unique_oen_from_smc_fid(smc_fid);
+	assert(idx >= 0 && idx < MAX_RT_SVCS);
+
+	index = rt_svc_descs_indices[idx];
+	if (index < 0 || index >= RT_SVC_DECS_NUM)
+		SMC_RET1(handle, SMC_UNK);
+
+	rt_svc_descs = (rt_svc_desc_t *) RT_SVC_DESCS_START;
+
+	get_smc_params_from_ctx(handle, x1, x2, x3, x4);
+
+	return rt_svc_descs[index].handle(smc_fid, x1, x2, x3, x4, cookie,
+						handle, flags);
+}
+
+/*******************************************************************************
  * Simple routine to sanity check a runtime service descriptor before using it
  ******************************************************************************/
 static int32_t validate_rt_svc_desc(const rt_svc_desc_t *desc)