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Achin Gupta86f23532019-10-11 15:41:16 +01001/*
2 * Copyright (c) 2020, ARM Limited and Contributors. All rights reserved.
3 *
4 * SPDX-License-Identifier: BSD-3-Clause
5 */
6
7#include <asm_macros.S>
8#include "../spmd_private.h"
9
10 .global spmd_spm_core_enter
11 .global spmd_spm_core_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 spmd_spm_core_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, #SPMD_C_RT_CTX_SIZE
26
27 /* Save callee-saved registers on to the stack */
28 stp x19, x20, [sp, #SPMD_C_RT_CTX_X19]
29 stp x21, x22, [sp, #SPMD_C_RT_CTX_X21]
30 stp x23, x24, [sp, #SPMD_C_RT_CTX_X23]
31 stp x25, x26, [sp, #SPMD_C_RT_CTX_X25]
32 stp x27, x28, [sp, #SPMD_C_RT_CTX_X27]
33 stp x29, x30, [sp, #SPMD_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 spmd_spm_core_enter
43
44 /* ---------------------------------------------------------------------
45 * This function is called with 'x0' pointing to a C runtime context.
46 * It restores the saved registers and jumps to that runtime with 'x0'
47 * as the new SP register. This destroys the C runtime context that had
48 * been built on the stack below the saved context by the caller. Later
49 * the second parameter 'x1' is passed as a return value to the caller.
50 * ---------------------------------------------------------------------
51 */
52func spmd_spm_core_exit
53 /* Restore the previous stack */
54 mov sp, x0
55
56 /* Restore callee-saved registers on to the stack */
57 ldp x19, x20, [x0, #(SPMD_C_RT_CTX_X19 - SPMD_C_RT_CTX_SIZE)]
58 ldp x21, x22, [x0, #(SPMD_C_RT_CTX_X21 - SPMD_C_RT_CTX_SIZE)]
59 ldp x23, x24, [x0, #(SPMD_C_RT_CTX_X23 - SPMD_C_RT_CTX_SIZE)]
60 ldp x25, x26, [x0, #(SPMD_C_RT_CTX_X25 - SPMD_C_RT_CTX_SIZE)]
61 ldp x27, x28, [x0, #(SPMD_C_RT_CTX_X27 - SPMD_C_RT_CTX_SIZE)]
62 ldp x29, x30, [x0, #(SPMD_C_RT_CTX_X29 - SPMD_C_RT_CTX_SIZE)]
63
64 /* ---------------------------------------------------------------------
65 * This should take us back to the instruction after the call to the
66 * last spm_secure_partition_enter().* Place the second parameter to x0
67 * so that the caller will see it as a return value from the original
68 * entry call.
69 * ---------------------------------------------------------------------
70 */
71 mov x0, x1
72 ret
73endfunc spmd_spm_core_exit