SPMD: add SPM dispatcher based upon SPCI Beta 0 spec
This patch adds a rudimentary SPM dispatcher component in EL3.
It does the following:
- Consumes the TOS_FW_CONFIG to determine properties of the SPM core
component
- Initialises the SPM core component which resides in the BL32 image
- Implements a handler for SPCI calls from either security state. Some
basic validation is done for each call but in most cases it is simply
forwarded as-is to the "other" security state.
Signed-off-by: Achin Gupta <achin.gupta@arm.com>
Signed-off-by: Artsem Artsemenka <artsem.artsemenka@arm.com>
Change-Id: I7d116814557f7255f4f4ebb797d1619d4fbab590
diff --git a/services/std_svc/spmd/aarch64/spmd_helpers.S b/services/std_svc/spmd/aarch64/spmd_helpers.S
new file mode 100644
index 0000000..d7bffca
--- /dev/null
+++ b/services/std_svc/spmd/aarch64/spmd_helpers.S
@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2020, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <asm_macros.S>
+#include "../spmd_private.h"
+
+ .global spmd_spm_core_enter
+ .global spmd_spm_core_exit
+
+ /* ---------------------------------------------------------------------
+ * This function is called with SP_EL0 as stack. Here we stash our EL3
+ * callee-saved registers on to the stack as a part of saving the C
+ * runtime and enter the secure payload.
+ * 'x0' contains a pointer to the memory where the address of the C
+ * runtime context is to be saved.
+ * ---------------------------------------------------------------------
+ */
+func spmd_spm_core_enter
+ /* Make space for the registers that we're going to save */
+ mov x3, sp
+ str x3, [x0, #0]
+ sub sp, sp, #SPMD_C_RT_CTX_SIZE
+
+ /* Save callee-saved registers on to the stack */
+ stp x19, x20, [sp, #SPMD_C_RT_CTX_X19]
+ stp x21, x22, [sp, #SPMD_C_RT_CTX_X21]
+ stp x23, x24, [sp, #SPMD_C_RT_CTX_X23]
+ stp x25, x26, [sp, #SPMD_C_RT_CTX_X25]
+ stp x27, x28, [sp, #SPMD_C_RT_CTX_X27]
+ stp x29, x30, [sp, #SPMD_C_RT_CTX_X29]
+
+ /* ---------------------------------------------------------------------
+ * Everything is setup now. el3_exit() will use the secure context to
+ * restore to the general purpose and EL3 system registers to ERET
+ * into the secure payload.
+ * ---------------------------------------------------------------------
+ */
+ b el3_exit
+endfunc spmd_spm_core_enter
+
+ /* ---------------------------------------------------------------------
+ * This function is called with 'x0' pointing to a C runtime context.
+ * It restores the saved registers and jumps to that runtime with 'x0'
+ * as the new SP register. This destroys the C runtime context that had
+ * been built on the stack below the saved context by the caller. Later
+ * the second parameter 'x1' is passed as a return value to the caller.
+ * ---------------------------------------------------------------------
+ */
+func spmd_spm_core_exit
+ /* Restore the previous stack */
+ mov sp, x0
+
+ /* Restore callee-saved registers on to the stack */
+ ldp x19, x20, [x0, #(SPMD_C_RT_CTX_X19 - SPMD_C_RT_CTX_SIZE)]
+ ldp x21, x22, [x0, #(SPMD_C_RT_CTX_X21 - SPMD_C_RT_CTX_SIZE)]
+ ldp x23, x24, [x0, #(SPMD_C_RT_CTX_X23 - SPMD_C_RT_CTX_SIZE)]
+ ldp x25, x26, [x0, #(SPMD_C_RT_CTX_X25 - SPMD_C_RT_CTX_SIZE)]
+ ldp x27, x28, [x0, #(SPMD_C_RT_CTX_X27 - SPMD_C_RT_CTX_SIZE)]
+ ldp x29, x30, [x0, #(SPMD_C_RT_CTX_X29 - SPMD_C_RT_CTX_SIZE)]
+
+ /* ---------------------------------------------------------------------
+ * This should take us back to the instruction after the call to the
+ * last spm_secure_partition_enter().* Place the second parameter to x0
+ * so that the caller will see it as a return value from the original
+ * entry call.
+ * ---------------------------------------------------------------------
+ */
+ mov x0, x1
+ ret
+endfunc spmd_spm_core_exit