1/*
2 * FreeRTOS Kernel V11.1.0
3 * Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
4 *
5 * SPDX-License-Identifier: MIT
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining a copy of
8 * this software and associated documentation files (the "Software"), to deal in
9 * the Software without restriction, including without limitation the rights to
10 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
11 * the Software, and to permit persons to whom the Software is furnished to do so,
12 * subject to the following conditions:
13 *
14 * The above copyright notice and this permission notice shall be included in all
15 * copies or substantial portions of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
19 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
20 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
21 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
22 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
23 *
24 * https://www.FreeRTOS.org
25 * https://github.com/FreeRTOS
26 *
27 */
28
29    SECTION .text:CODE:NOROOT(2)
30    THUMB
31
32/* Including FreeRTOSConfig.h here will cause build errors if the header file
33contains code not understood by the assembler - for example the 'extern' keyword.
34To avoid errors place any such code inside a #ifdef __ICCARM__/#endif block so
35the code is included in C files but excluded by the preprocessor in assembly
36files (__ICCARM__ is defined by the IAR C compiler but not by the IAR assembler. */
37#include "FreeRTOSConfig.h"
38
39    PUBLIC SecureContext_LoadContextAsm
40    PUBLIC SecureContext_SaveContextAsm
41
42#if ( configENABLE_FPU == 1 )
43    #error Cortex-M23 does not have a Floating Point Unit (FPU) and therefore configENABLE_FPU must be set to 0.
44#endif
45/*-----------------------------------------------------------*/
46
47SecureContext_LoadContextAsm:
48    /* pxSecureContext value is in r0. */
49    mrs r1, ipsr                    /* r1 = IPSR. */
50    cbz r1, load_ctx_therad_mode    /* Do nothing if the processor is running in the Thread Mode. */
51    ldmia r0!, {r1, r2}             /* r1 = pxSecureContext->pucCurrentStackPointer, r2 = pxSecureContext->pucStackLimit. */
52
53#if ( configENABLE_MPU == 1 )
54    ldmia r1!, {r3}                 /* Read CONTROL register value from task's stack. r3 = CONTROL. */
55    msr control, r3                 /* CONTROL = r3. */
56#endif /* configENABLE_MPU */
57
58    msr psplim, r2                  /* PSPLIM = r2. */
59    msr psp, r1                     /* PSP = r1. */
60
61    load_ctx_therad_mode:
62        bx lr
63/*-----------------------------------------------------------*/
64
65SecureContext_SaveContextAsm:
66    /* pxSecureContext value is in r0. */
67    mrs r1, ipsr                    /* r1 = IPSR. */
68    cbz r1, save_ctx_therad_mode    /* Do nothing if the processor is running in the Thread Mode. */
69    mrs r1, psp                     /* r1 = PSP. */
70
71#if ( configENABLE_MPU == 1 )
72    mrs r2, control                 /* r2 = CONTROL. */
73    subs r1, r1, #4                 /* Make space for the CONTROL value on the stack. */
74    str r1, [r0]                    /* Save the top of stack in context. pxSecureContext->pucCurrentStackPointer = r1. */
75    stmia r1!, {r2}                 /* Store CONTROL value on the stack. */
76#else /* configENABLE_MPU */
77    str r1, [r0]                    /* Save the top of stack in context. pxSecureContext->pucCurrentStackPointer = r1. */
78#endif /* configENABLE_MPU */
79
80    movs r1, #0                     /* r1 = securecontextNO_STACK. */
81    msr psplim, r1                  /* PSPLIM = securecontextNO_STACK. */
82    msr psp, r1                     /* PSP = securecontextNO_STACK i.e. No stack for thread mode until next task's context is loaded. */
83
84    save_ctx_therad_mode:
85        bx lr
86/*-----------------------------------------------------------*/
87
88    END
89