blob: aa35811f14af8079c6f9ca36aa8c408d910ca490 [file] [log] [blame]
Antonio Nino Diazc41f2062017-10-24 10:07:35 +01001/*
2 * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
3 *
4 * SPDX-License-Identifier: BSD-3-Clause
5 */
6
7#include <asm_macros.S>
8#include "../spm_private.h"
9
10 .global spm_secure_partition_enter
11 .global spm_secure_partition_exit
12
13 /* ---------------------------------------------------------------------
14 * This function is called with SP_EL0 as stack. Here we stash our EL3
15 * callee-saved registers on to the stack as a part of saving the C
16 * runtime and enter the secure payload.
17 * 'x0' contains a pointer to the memory where the address of the C
18 * runtime context is to be saved.
19 * ---------------------------------------------------------------------
20 */
21func spm_secure_partition_enter
22 /* Make space for the registers that we're going to save */
23 mov x3, sp
24 str x3, [x0, #0]
25 sub sp, sp, #SP_C_RT_CTX_SIZE
26
27 /* Save callee-saved registers on to the stack */
28 stp x19, x20, [sp, #SP_C_RT_CTX_X19]
29 stp x21, x22, [sp, #SP_C_RT_CTX_X21]
30 stp x23, x24, [sp, #SP_C_RT_CTX_X23]
31 stp x25, x26, [sp, #SP_C_RT_CTX_X25]
32 stp x27, x28, [sp, #SP_C_RT_CTX_X27]
33 stp x29, x30, [sp, #SP_C_RT_CTX_X29]
34
35 /* ---------------------------------------------------------------------
36 * Everything is setup now. el3_exit() will use the secure context to
37 * restore to the general purpose and EL3 system registers to ERET
38 * into the secure payload.
39 * ---------------------------------------------------------------------
40 */
41 b el3_exit
42endfunc spm_secure_partition_enter
43
44 /* ---------------------------------------------------------------------
45 * This function is called with 'x0' pointing to a C runtime context
46 * saved in spm_secure_partition_enter().
47 * It restores the saved registers and jumps to that runtime with 'x0'
48 * as the new SP register. This destroys the C runtime context that had
49 * been built on the stack below the saved context by the caller. Later
50 * the second parameter 'x1' is passed as a return value to the caller.
51 * ---------------------------------------------------------------------
52 */
53func spm_secure_partition_exit
54 /* Restore the previous stack */
55 mov sp, x0
56
57 /* Restore callee-saved registers on to the stack */
58 ldp x19, x20, [x0, #(SP_C_RT_CTX_X19 - SP_C_RT_CTX_SIZE)]
59 ldp x21, x22, [x0, #(SP_C_RT_CTX_X21 - SP_C_RT_CTX_SIZE)]
60 ldp x23, x24, [x0, #(SP_C_RT_CTX_X23 - SP_C_RT_CTX_SIZE)]
61 ldp x25, x26, [x0, #(SP_C_RT_CTX_X25 - SP_C_RT_CTX_SIZE)]
62 ldp x27, x28, [x0, #(SP_C_RT_CTX_X27 - SP_C_RT_CTX_SIZE)]
63 ldp x29, x30, [x0, #(SP_C_RT_CTX_X29 - SP_C_RT_CTX_SIZE)]
64
65 /* ---------------------------------------------------------------------
66 * This should take us back to the instruction after the call to the
67 * last spm_secure_partition_enter().* Place the second parameter to x0
68 * so that the caller will see it as a return value from the original
69 * entry call.
70 * ---------------------------------------------------------------------
71 */
72 mov x0, x1
73 ret
74endfunc spm_secure_partition_exit