SPM: Deprecate the current implementation
The current SPM is a prototype that only supports one secure partition
in EL0. The objective of SPM is to have multiple partitions. The current
MM interface isn't adequate for this, so it is needed to modify heavily
the code to add proper support for it.
However, there are platforms which are already using this (like SGI) and
removing the code would break it. For this reason, the current SPM code
has been duplicated in order to temporarily preserve compatibility. All
new improvements/changes to SPM will be done in the non-deprecated copy,
that may change without notice.
The new build option SPM_DEPRECATED has been introduced to select the SPM
implementation. It defaults to 1, that selects the deprecated SPM.
Change-Id: Ic9f80b53b450e97b4d3f47e4ef4a138ee8d87443
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/services/std_svc/spm_deprecated/aarch64/spm_helpers.S b/services/std_svc/spm_deprecated/aarch64/spm_helpers.S
new file mode 100644
index 0000000..aa35811
--- /dev/null
+++ b/services/std_svc/spm_deprecated/aarch64/spm_helpers.S
@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <asm_macros.S>
+#include "../spm_private.h"
+
+ .global spm_secure_partition_enter
+ .global spm_secure_partition_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 spm_secure_partition_enter
+ /* Make space for the registers that we're going to save */
+ mov x3, sp
+ str x3, [x0, #0]
+ sub sp, sp, #SP_C_RT_CTX_SIZE
+
+ /* Save callee-saved registers on to the stack */
+ stp x19, x20, [sp, #SP_C_RT_CTX_X19]
+ stp x21, x22, [sp, #SP_C_RT_CTX_X21]
+ stp x23, x24, [sp, #SP_C_RT_CTX_X23]
+ stp x25, x26, [sp, #SP_C_RT_CTX_X25]
+ stp x27, x28, [sp, #SP_C_RT_CTX_X27]
+ stp x29, x30, [sp, #SP_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 spm_secure_partition_enter
+
+ /* ---------------------------------------------------------------------
+ * This function is called with 'x0' pointing to a C runtime context
+ * saved in spm_secure_partition_enter().
+ * 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 spm_secure_partition_exit
+ /* Restore the previous stack */
+ mov sp, x0
+
+ /* Restore callee-saved registers on to the stack */
+ ldp x19, x20, [x0, #(SP_C_RT_CTX_X19 - SP_C_RT_CTX_SIZE)]
+ ldp x21, x22, [x0, #(SP_C_RT_CTX_X21 - SP_C_RT_CTX_SIZE)]
+ ldp x23, x24, [x0, #(SP_C_RT_CTX_X23 - SP_C_RT_CTX_SIZE)]
+ ldp x25, x26, [x0, #(SP_C_RT_CTX_X25 - SP_C_RT_CTX_SIZE)]
+ ldp x27, x28, [x0, #(SP_C_RT_CTX_X27 - SP_C_RT_CTX_SIZE)]
+ ldp x29, x30, [x0, #(SP_C_RT_CTX_X29 - SP_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 spm_secure_partition_exit