feat(services): add a SPD for ProvenCore
Adds a dispatcher for ProvenCore based on the test secure payload
dispatcher.
Signed-off-by: Florian Lugou <florian.lugou@provenrun.com>
Change-Id: I978afc3af6a6f65791655685a7bc80070673c9f3
diff --git a/services/spd/pncd/pncd_helpers.S b/services/spd/pncd/pncd_helpers.S
new file mode 100644
index 0000000..736b30f
--- /dev/null
+++ b/services/spd/pncd/pncd_helpers.S
@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2021-2022, ProvenRun S.A.S. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <asm_macros.S>
+#include "pncd_private.h"
+
+ .global pncd_enter_sp
+ /* ---------------------------------------------
+ * 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 pncd_enter_sp
+ /* Make space for the registers that we're going to save */
+ mov x3, sp
+ str x3, [x0, #0]
+ sub sp, sp, #PNCD_C_RT_CTX_SIZE
+
+ /* Save callee-saved registers on to the stack */
+ stp x19, x20, [sp, #PNCD_C_RT_CTX_X19]
+ stp x21, x22, [sp, #PNCD_C_RT_CTX_X21]
+ stp x23, x24, [sp, #PNCD_C_RT_CTX_X23]
+ stp x25, x26, [sp, #PNCD_C_RT_CTX_X25]
+ stp x27, x28, [sp, #PNCD_C_RT_CTX_X27]
+ stp x29, x30, [sp, #PNCD_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 pncd_enter_sp
+
+ /* ---------------------------------------------
+ * This function is called 'x0' pointing to a C
+ * runtime context saved in pncd_enter_sp(). It
+ * restores the saved registers and jumps to
+ * that runtime with 'x0' as the new sp. 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 return value to the caller
+ * ---------------------------------------------
+ */
+ .global pncd_exit_sp
+func pncd_exit_sp
+ /* Restore the previous stack */
+ mov sp, x0
+
+ /* Restore callee-saved registers on to the stack */
+ ldp x19, x20, [x0, #(PNCD_C_RT_CTX_X19 - PNCD_C_RT_CTX_SIZE)]
+ ldp x21, x22, [x0, #(PNCD_C_RT_CTX_X21 - PNCD_C_RT_CTX_SIZE)]
+ ldp x23, x24, [x0, #(PNCD_C_RT_CTX_X23 - PNCD_C_RT_CTX_SIZE)]
+ ldp x25, x26, [x0, #(PNCD_C_RT_CTX_X25 - PNCD_C_RT_CTX_SIZE)]
+ ldp x27, x28, [x0, #(PNCD_C_RT_CTX_X27 - PNCD_C_RT_CTX_SIZE)]
+ ldp x29, x30, [x0, #(PNCD_C_RT_CTX_X29 - PNCD_C_RT_CTX_SIZE)]
+
+ /* ---------------------------------------------
+ * This should take us back to the instruction
+ * after the call to the last pncd_enter_sp().
+ * 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 pncd_exit_sp