You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
352 lines
14 KiB
C
352 lines
14 KiB
C
/*
|
|
* FreeRTOS Kernel <DEVELOPMENT BRANCH>
|
|
* Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
|
|
*
|
|
* SPDX-License-Identifier: MIT
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person obtaining a copy of
|
|
* this software and associated documentation files (the "Software"), to deal in
|
|
* the Software without restriction, including without limitation the rights to
|
|
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
|
|
* the Software, and to permit persons to whom the Software is furnished to do so,
|
|
* subject to the following conditions:
|
|
*
|
|
* The above copyright notice and this permission notice shall be included in all
|
|
* copies or substantial portions of the Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
|
|
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
|
|
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
|
|
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
|
|
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
|
|
*
|
|
* https://www.FreeRTOS.org
|
|
* https://github.com/FreeRTOS
|
|
*
|
|
*/
|
|
|
|
/* Secure context includes. */
|
|
#include "secure_context.h"
|
|
|
|
/* Secure heap includes. */
|
|
#include "secure_heap.h"
|
|
|
|
/* Secure port macros. */
|
|
#include "secure_port_macros.h"
|
|
|
|
/**
|
|
* @brief CONTROL value for privileged tasks.
|
|
*
|
|
* Bit[0] - 0 --> Thread mode is privileged.
|
|
* Bit[1] - 1 --> Thread mode uses PSP.
|
|
*/
|
|
#define securecontextCONTROL_VALUE_PRIVILEGED 0x02
|
|
|
|
/**
|
|
* @brief CONTROL value for un-privileged tasks.
|
|
*
|
|
* Bit[0] - 1 --> Thread mode is un-privileged.
|
|
* Bit[1] - 1 --> Thread mode uses PSP.
|
|
*/
|
|
#define securecontextCONTROL_VALUE_UNPRIVILEGED 0x03
|
|
|
|
/**
|
|
* @brief Size of stack seal values in bytes.
|
|
*/
|
|
#define securecontextSTACK_SEAL_SIZE 8
|
|
|
|
/**
|
|
* @brief Stack seal value as recommended by ARM.
|
|
*/
|
|
#define securecontextSTACK_SEAL_VALUE 0xFEF5EDA5
|
|
|
|
/**
|
|
* @brief Maximum number of secure contexts.
|
|
*/
|
|
#ifndef secureconfigMAX_SECURE_CONTEXTS
|
|
#define secureconfigMAX_SECURE_CONTEXTS 8UL
|
|
#endif
|
|
/*-----------------------------------------------------------*/
|
|
|
|
/**
|
|
* @brief Pre-allocated array of secure contexts.
|
|
*/
|
|
SecureContext_t xSecureContexts[ secureconfigMAX_SECURE_CONTEXTS ];
|
|
/*-----------------------------------------------------------*/
|
|
|
|
/**
|
|
* @brief Get a free secure context for a task from the secure context pool (xSecureContexts).
|
|
*
|
|
* This function ensures that only one secure context is allocated for a task.
|
|
*
|
|
* @param[in] pvTaskHandle The task handle for which the secure context is allocated.
|
|
*
|
|
* @return Index of a free secure context in the xSecureContexts array.
|
|
*/
|
|
static uint32_t ulGetSecureContext( void * pvTaskHandle );
|
|
|
|
/**
|
|
* @brief Return the secure context to the secure context pool (xSecureContexts).
|
|
*
|
|
* @param[in] ulSecureContextIndex Index of the context in the xSecureContexts array.
|
|
*/
|
|
static void vReturnSecureContext( uint32_t ulSecureContextIndex );
|
|
|
|
/* These are implemented in assembly. */
|
|
extern void SecureContext_LoadContextAsm( SecureContext_t * pxSecureContext );
|
|
extern void SecureContext_SaveContextAsm( SecureContext_t * pxSecureContext );
|
|
/*-----------------------------------------------------------*/
|
|
|
|
static uint32_t ulGetSecureContext( void * pvTaskHandle )
|
|
{
|
|
/* Start with invalid index. */
|
|
uint32_t i, ulSecureContextIndex = secureconfigMAX_SECURE_CONTEXTS;
|
|
|
|
for( i = 0; i < secureconfigMAX_SECURE_CONTEXTS; i++ )
|
|
{
|
|
if( ( xSecureContexts[ i ].pucCurrentStackPointer == NULL ) &&
|
|
( xSecureContexts[ i ].pucStackLimit == NULL ) &&
|
|
( xSecureContexts[ i ].pucStackStart == NULL ) &&
|
|
( xSecureContexts[ i ].pvTaskHandle == NULL ) &&
|
|
( ulSecureContextIndex == secureconfigMAX_SECURE_CONTEXTS ) )
|
|
{
|
|
ulSecureContextIndex = i;
|
|
}
|
|
else if( xSecureContexts[ i ].pvTaskHandle == pvTaskHandle )
|
|
{
|
|
/* A task can only have one secure context. Do not allocate a second
|
|
* context for the same task. */
|
|
ulSecureContextIndex = secureconfigMAX_SECURE_CONTEXTS;
|
|
break;
|
|
}
|
|
}
|
|
|
|
return ulSecureContextIndex;
|
|
}
|
|
/*-----------------------------------------------------------*/
|
|
|
|
static void vReturnSecureContext( uint32_t ulSecureContextIndex )
|
|
{
|
|
xSecureContexts[ ulSecureContextIndex ].pucCurrentStackPointer = NULL;
|
|
xSecureContexts[ ulSecureContextIndex ].pucStackLimit = NULL;
|
|
xSecureContexts[ ulSecureContextIndex ].pucStackStart = NULL;
|
|
xSecureContexts[ ulSecureContextIndex ].pvTaskHandle = NULL;
|
|
}
|
|
/*-----------------------------------------------------------*/
|
|
|
|
secureportNON_SECURE_CALLABLE void SecureContext_Init( void )
|
|
{
|
|
uint32_t ulIPSR, i;
|
|
static uint32_t ulSecureContextsInitialized = 0;
|
|
|
|
/* Read the Interrupt Program Status Register (IPSR) value. */
|
|
secureportREAD_IPSR( ulIPSR );
|
|
|
|
/* Do nothing if the processor is running in the Thread Mode. IPSR is zero
|
|
* when the processor is running in the Thread Mode. */
|
|
if( ( ulIPSR != 0 ) && ( ulSecureContextsInitialized == 0 ) )
|
|
{
|
|
/* Ensure to initialize secure contexts only once. */
|
|
ulSecureContextsInitialized = 1;
|
|
|
|
/* No stack for thread mode until a task's context is loaded. */
|
|
secureportSET_PSPLIM( securecontextNO_STACK );
|
|
secureportSET_PSP( securecontextNO_STACK );
|
|
|
|
/* Initialize all secure contexts. */
|
|
for( i = 0; i < secureconfigMAX_SECURE_CONTEXTS; i++ )
|
|
{
|
|
xSecureContexts[ i ].pucCurrentStackPointer = NULL;
|
|
xSecureContexts[ i ].pucStackLimit = NULL;
|
|
xSecureContexts[ i ].pucStackStart = NULL;
|
|
xSecureContexts[ i ].pvTaskHandle = NULL;
|
|
}
|
|
|
|
#if ( configENABLE_MPU == 1 )
|
|
{
|
|
/* Configure thread mode to use PSP and to be unprivileged. */
|
|
secureportSET_CONTROL( securecontextCONTROL_VALUE_UNPRIVILEGED );
|
|
}
|
|
#else /* configENABLE_MPU */
|
|
{
|
|
/* Configure thread mode to use PSP and to be privileged. */
|
|
secureportSET_CONTROL( securecontextCONTROL_VALUE_PRIVILEGED );
|
|
}
|
|
#endif /* configENABLE_MPU */
|
|
}
|
|
}
|
|
/*-----------------------------------------------------------*/
|
|
|
|
#if ( configENABLE_MPU == 1 )
|
|
secureportNON_SECURE_CALLABLE SecureContextHandle_t SecureContext_AllocateContext( uint32_t ulSecureStackSize,
|
|
uint32_t ulIsTaskPrivileged,
|
|
void * pvTaskHandle )
|
|
#else /* configENABLE_MPU */
|
|
secureportNON_SECURE_CALLABLE SecureContextHandle_t SecureContext_AllocateContext( uint32_t ulSecureStackSize,
|
|
void * pvTaskHandle )
|
|
#endif /* configENABLE_MPU */
|
|
{
|
|
uint8_t * pucStackMemory = NULL;
|
|
uint8_t * pucStackLimit;
|
|
uint32_t ulIPSR, ulSecureContextIndex;
|
|
SecureContextHandle_t xSecureContextHandle = securecontextINVALID_CONTEXT_ID;
|
|
|
|
#if ( configENABLE_MPU == 1 )
|
|
uint32_t * pulCurrentStackPointer = NULL;
|
|
#endif /* configENABLE_MPU */
|
|
|
|
/* Read the Interrupt Program Status Register (IPSR) and Process Stack Limit
|
|
* Register (PSPLIM) value. */
|
|
secureportREAD_IPSR( ulIPSR );
|
|
secureportREAD_PSPLIM( pucStackLimit );
|
|
|
|
/* Do nothing if the processor is running in the Thread Mode. IPSR is zero
|
|
* when the processor is running in the Thread Mode.
|
|
* Also do nothing, if a secure context us already loaded. PSPLIM is set to
|
|
* securecontextNO_STACK when no secure context is loaded. */
|
|
if( ( ulIPSR != 0 ) && ( pucStackLimit == securecontextNO_STACK ) )
|
|
{
|
|
/* Ontain a free secure context. */
|
|
ulSecureContextIndex = ulGetSecureContext( pvTaskHandle );
|
|
|
|
/* Were we able to get a free context? */
|
|
if( ulSecureContextIndex < secureconfigMAX_SECURE_CONTEXTS )
|
|
{
|
|
/* Allocate the stack space. */
|
|
pucStackMemory = pvPortMalloc( ulSecureStackSize + securecontextSTACK_SEAL_SIZE );
|
|
|
|
if( pucStackMemory != NULL )
|
|
{
|
|
/* Since stack grows down, the starting point will be the last
|
|
* location. Note that this location is next to the last
|
|
* allocated byte for stack (excluding the space for seal values)
|
|
* because the hardware decrements the stack pointer before
|
|
* writing i.e. if stack pointer is 0x2, a push operation will
|
|
* decrement the stack pointer to 0x1 and then write at 0x1. */
|
|
xSecureContexts[ ulSecureContextIndex ].pucStackStart = pucStackMemory + ulSecureStackSize;
|
|
|
|
/* Seal the created secure process stack. */
|
|
*( uint32_t * )( pucStackMemory + ulSecureStackSize ) = securecontextSTACK_SEAL_VALUE;
|
|
*( uint32_t * )( pucStackMemory + ulSecureStackSize + 4 ) = securecontextSTACK_SEAL_VALUE;
|
|
|
|
/* The stack cannot go beyond this location. This value is
|
|
* programmed in the PSPLIM register on context switch.*/
|
|
xSecureContexts[ ulSecureContextIndex ].pucStackLimit = pucStackMemory;
|
|
|
|
xSecureContexts[ ulSecureContextIndex ].pvTaskHandle = pvTaskHandle;
|
|
|
|
#if ( configENABLE_MPU == 1 )
|
|
{
|
|
/* Store the correct CONTROL value for the task on the stack.
|
|
* This value is programmed in the CONTROL register on
|
|
* context switch. */
|
|
pulCurrentStackPointer = ( uint32_t * ) xSecureContexts[ ulSecureContextIndex ].pucStackStart;
|
|
pulCurrentStackPointer--;
|
|
|
|
if( ulIsTaskPrivileged )
|
|
{
|
|
*( pulCurrentStackPointer ) = securecontextCONTROL_VALUE_PRIVILEGED;
|
|
}
|
|
else
|
|
{
|
|
*( pulCurrentStackPointer ) = securecontextCONTROL_VALUE_UNPRIVILEGED;
|
|
}
|
|
|
|
/* Store the current stack pointer. This value is programmed in
|
|
* the PSP register on context switch. */
|
|
xSecureContexts[ ulSecureContextIndex ].pucCurrentStackPointer = ( uint8_t * ) pulCurrentStackPointer;
|
|
}
|
|
#else /* configENABLE_MPU */
|
|
{
|
|
/* Current SP is set to the starting of the stack. This
|
|
* value programmed in the PSP register on context switch. */
|
|
xSecureContexts[ ulSecureContextIndex ].pucCurrentStackPointer = xSecureContexts[ ulSecureContextIndex ].pucStackStart;
|
|
}
|
|
#endif /* configENABLE_MPU */
|
|
|
|
/* Ensure to never return 0 as a valid context handle. */
|
|
xSecureContextHandle = ulSecureContextIndex + 1UL;
|
|
}
|
|
}
|
|
}
|
|
|
|
return xSecureContextHandle;
|
|
}
|
|
/*-----------------------------------------------------------*/
|
|
|
|
secureportNON_SECURE_CALLABLE void SecureContext_FreeContext( SecureContextHandle_t xSecureContextHandle, void * pvTaskHandle )
|
|
{
|
|
uint32_t ulIPSR, ulSecureContextIndex;
|
|
|
|
/* Read the Interrupt Program Status Register (IPSR) value. */
|
|
secureportREAD_IPSR( ulIPSR );
|
|
|
|
/* Do nothing if the processor is running in the Thread Mode. IPSR is zero
|
|
* when the processor is running in the Thread Mode. */
|
|
if( ulIPSR != 0 )
|
|
{
|
|
/* Only free if a valid context handle is passed. */
|
|
if( ( xSecureContextHandle > 0UL ) && ( xSecureContextHandle <= secureconfigMAX_SECURE_CONTEXTS ) )
|
|
{
|
|
ulSecureContextIndex = xSecureContextHandle - 1UL;
|
|
|
|
/* Ensure that the secure context being deleted is associated with
|
|
* the task. */
|
|
if( xSecureContexts[ ulSecureContextIndex ].pvTaskHandle == pvTaskHandle )
|
|
{
|
|
/* Free the stack space. */
|
|
vPortFree( xSecureContexts[ ulSecureContextIndex ].pucStackLimit );
|
|
|
|
/* Return the secure context back to the free secure contexts pool. */
|
|
vReturnSecureContext( ulSecureContextIndex );
|
|
}
|
|
}
|
|
}
|
|
}
|
|
/*-----------------------------------------------------------*/
|
|
|
|
secureportNON_SECURE_CALLABLE void SecureContext_LoadContext( SecureContextHandle_t xSecureContextHandle, void * pvTaskHandle )
|
|
{
|
|
uint8_t * pucStackLimit;
|
|
uint32_t ulSecureContextIndex;
|
|
|
|
if( ( xSecureContextHandle > 0UL ) && ( xSecureContextHandle <= secureconfigMAX_SECURE_CONTEXTS ) )
|
|
{
|
|
ulSecureContextIndex = xSecureContextHandle - 1UL;
|
|
|
|
secureportREAD_PSPLIM( pucStackLimit );
|
|
|
|
/* Ensure that no secure context is loaded and the task is loading it's
|
|
* own context. */
|
|
if( ( pucStackLimit == securecontextNO_STACK ) &&
|
|
( xSecureContexts[ ulSecureContextIndex ].pvTaskHandle == pvTaskHandle ) )
|
|
{
|
|
SecureContext_LoadContextAsm( &( xSecureContexts[ ulSecureContextIndex ] ) );
|
|
}
|
|
}
|
|
}
|
|
/*-----------------------------------------------------------*/
|
|
|
|
secureportNON_SECURE_CALLABLE void SecureContext_SaveContext( SecureContextHandle_t xSecureContextHandle, void * pvTaskHandle )
|
|
{
|
|
uint8_t * pucStackLimit;
|
|
uint32_t ulSecureContextIndex;
|
|
|
|
if( ( xSecureContextHandle > 0UL ) && ( xSecureContextHandle <= secureconfigMAX_SECURE_CONTEXTS ) )
|
|
{
|
|
ulSecureContextIndex = xSecureContextHandle - 1UL;
|
|
|
|
secureportREAD_PSPLIM( pucStackLimit );
|
|
|
|
/* Ensure that task's context is loaded and the task is saving it's own
|
|
* context. */
|
|
if( ( xSecureContexts[ ulSecureContextIndex ].pucStackLimit == pucStackLimit ) &&
|
|
( xSecureContexts[ ulSecureContextIndex ].pvTaskHandle == pvTaskHandle ) )
|
|
{
|
|
SecureContext_SaveContextAsm( &( xSecureContexts[ ulSecureContextIndex ] ) );
|
|
}
|
|
}
|
|
}
|
|
/*-----------------------------------------------------------*/
|