aboutsummaryrefslogtreecommitdiff
path: root/services/spd/tspd/tspd_helpers.S
diff options
context:
space:
mode:
Diffstat (limited to 'services/spd/tspd/tspd_helpers.S')
-rw-r--r--services/spd/tspd/tspd_helpers.S103
1 files changed, 103 insertions, 0 deletions
diff --git a/services/spd/tspd/tspd_helpers.S b/services/spd/tspd/tspd_helpers.S
new file mode 100644
index 0000000..b56b2aa
--- /dev/null
+++ b/services/spd/tspd/tspd_helpers.S
@@ -0,0 +1,103 @@
+/*
+ * Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * Neither the name of ARM nor the names of its contributors may be used
+ * to endorse or promote products derived from this software without specific
+ * prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <context.h>
+#include <tspd_private.h>
+#include <asm_macros.S>
+#include <cm_macros.S>
+
+ .global tspd_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.
+ * ---------------------------------------------
+ */
+tspd_enter_sp:
+ /* Make space for the registers that we're going to save */
+ mov x3, sp
+ str x3, [x0, #0]
+ sub sp, sp, #TSPD_C_RT_CTX_SIZE
+
+ /* Save callee-saved registers on to the stack */
+ stp x19, x20, [sp, #TSPD_C_RT_CTX_X19]
+ stp x21, x22, [sp, #TSPD_C_RT_CTX_X21]
+ stp x23, x24, [sp, #TSPD_C_RT_CTX_X23]
+ stp x25, x26, [sp, #TSPD_C_RT_CTX_X25]
+ stp x27, x28, [sp, #TSPD_C_RT_CTX_X27]
+ stp x29, x30, [sp, #TSPD_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
+
+ /* ---------------------------------------------
+ * This function is called 'x0' pointing to a C
+ * runtime context saved in tspd_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 tspd_exit_sp
+tspd_exit_sp:
+ /* Restore the previous stack */
+ mov sp, x0
+
+ /* Restore callee-saved registers on to the stack */
+ ldp x19, x20, [x0, #(TSPD_C_RT_CTX_X19 - TSPD_C_RT_CTX_SIZE)]
+ ldp x21, x22, [x0, #(TSPD_C_RT_CTX_X21 - TSPD_C_RT_CTX_SIZE)]
+ ldp x23, x24, [x0, #(TSPD_C_RT_CTX_X23 - TSPD_C_RT_CTX_SIZE)]
+ ldp x25, x26, [x0, #(TSPD_C_RT_CTX_X25 - TSPD_C_RT_CTX_SIZE)]
+ ldp x27, x28, [x0, #(TSPD_C_RT_CTX_X27 - TSPD_C_RT_CTX_SIZE)]
+ ldp x29, x30, [x0, #(TSPD_C_RT_CTX_X29 - TSPD_C_RT_CTX_SIZE)]
+
+ /* ---------------------------------------------
+ * This should take us back to the instruction
+ * after the call to the last tspd_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