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Merged
merged 5 commits into from
Dec 11, 2018
Merged

Reduce ROM impact of MPU code #9030

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e2f6025
Exclude MPU manager code if MPU disabled
kjbracey Dec 10, 2018
842587d
Save ROM by specifying initial MPU state
kjbracey Dec 10, 2018
1289406
Use MBED_ASSERT in MPU manager
kjbracey Dec 10, 2018
13a24bc
Test MPU is enabled by init
kjbracey Dec 10, 2018
390ef30
Add header to fix compile failures
c1728p9 Dec 10, 2018
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8 changes: 3 additions & 5 deletions TESTS/mbed_hal/mpu/main.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -72,11 +72,9 @@ static void hard_fault_handler_test()

static void mpu_fault_test(const volatile uint16_t *mem_function)
{
mbed_mpu_init();

// Verify that the mpu causes faults when executing ram
// Verify that the mpu causes faults when executing ram after init
fault_count = 0;
mbed_mpu_enable_ram_xn(true);
mbed_mpu_init();
call_mem(mem_function);
TEST_ASSERT_EQUAL(1, fault_count);

Expand All @@ -86,7 +84,7 @@ static void mpu_fault_test(const volatile uint16_t *mem_function)
call_mem(mem_function);
TEST_ASSERT_EQUAL(0, fault_count);

// Verify that the mpu causes faults when executing ram
// Verify that the mpu can be turned back on
fault_count = 0;
mbed_mpu_enable_ram_xn(true);
call_mem(mem_function);
Expand Down
12 changes: 8 additions & 4 deletions hal/mpu/mbed_mpu_v8m.c
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Expand Up @@ -78,7 +78,8 @@ void mbed_mpu_init()
(3 << MPU_RBAR_AP_Pos) | // RO allowed by all privilege levels
(0 << MPU_RBAR_XN_Pos); // Execute Never disabled
MPU->RLAR = (0x1FFFFFFF & MPU_RLAR_LIMIT_Msk) | // Last address is 0x1FFFFFFF
(region << MPU_RLAR_AttrIndx_Pos); // Attribute index - configured to be the same as the region number
(region << MPU_RLAR_AttrIndx_Pos) | // Attribute index - configured to be the same as the region number
(1 << MPU_RLAR_EN_Pos); // Region enabled

region = 1;
MPU->RNR = region;
Expand All @@ -90,7 +91,8 @@ void mbed_mpu_init()
(1 << MPU_RBAR_AP_Pos) | // RW allowed by all privilege levels
(1 << MPU_RBAR_XN_Pos); // Execute Never enabled
MPU->RLAR = (0x3FFFFFFF & MPU_RLAR_LIMIT_Msk) | // Last address is 0x3FFFFFFF
(region << MPU_RLAR_AttrIndx_Pos); // Attribute index - configured to be the same as the region number
(region << MPU_RLAR_AttrIndx_Pos) | // Attribute index - configured to be the same as the region number
(1 << MPU_RLAR_EN_Pos); // Region enabled

region = 2;
MPU->RNR = region;
Expand All @@ -102,7 +104,8 @@ void mbed_mpu_init()
(1 << MPU_RBAR_AP_Pos) | // RW allowed by all privilege levels
(1 << MPU_RBAR_XN_Pos); // Execute Never enabled
MPU->RLAR = (0x7FFFFFFF & MPU_RLAR_LIMIT_Msk) | // Last address is 0x7FFFFFFF
(region << MPU_RLAR_AttrIndx_Pos); // Attribute index - configured to be the same as the region number
(region << MPU_RLAR_AttrIndx_Pos) | // Attribute index - configured to be the same as the region number
(1 << MPU_RLAR_EN_Pos); // Region enabled

region = 3;
MPU->RNR = region;
Expand All @@ -114,7 +117,8 @@ void mbed_mpu_init()
(1 << MPU_RBAR_AP_Pos) | // RW allowed by all privilege levels
(1 << MPU_RBAR_XN_Pos); // Execute Never enabled
MPU->RLAR = (0x9FFFFFFF & MPU_RLAR_LIMIT_Msk) | // Last address is 0x9FFFFFFF
(region << MPU_RLAR_AttrIndx_Pos); // Attribute index - configured to be the same as the region number
(region << MPU_RLAR_AttrIndx_Pos) | // Attribute index - configured to be the same as the region number
(1 << MPU_RLAR_EN_Pos); // Region enabled

// Enable the MPU
MPU->CTRL =
Expand Down
12 changes: 8 additions & 4 deletions hal/mpu_api.h
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Expand Up @@ -64,8 +64,8 @@ extern "C" {
* Initialize the MPU
*
* Initialize or re-initialize the memory protection unit.
* It is implementation defined what region are protected
* by the MPU after initialization.
* After initialization or re-initialization, ROM and RAM protection
* are both enabled.
*/
void mbed_mpu_init(void);

Expand All @@ -75,7 +75,9 @@ void mbed_mpu_init(void);
* This function is used to mark all of ROM as read and execute only.
* When enabled writes to ROM cause a fault.
*
* @param enable true to disable execution in ram, false otherwise
* By default writes to ROM are disabled.
*
* @param enable true to disable writes to ROM, false otherwise
*/
void mbed_mpu_enable_rom_wn(bool enable);

Expand All @@ -85,7 +87,9 @@ void mbed_mpu_enable_rom_wn(bool enable);
* This function is used to mark all of RAM as execute never.
* When enabled code is only allowed to execute from flash.
*
* @param enable true to disable execution in ram, false otherwise
* By default execution from RAM is disabled.
*
* @param enable true to disable execution from RAM, false otherwise
*/
void mbed_mpu_enable_ram_xn(bool enable);

Expand Down
25 changes: 9 additions & 16 deletions platform/mbed_mpu_mgmt.c
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Original file line number Diff line number Diff line change
Expand Up @@ -17,19 +17,19 @@
#include "platform/mbed_mpu_mgmt.h"
#include "platform/mbed_critical.h"
#include "platform/mbed_error.h"
#include "platform/mbed_assert.h"
#include "hal/mpu_api.h"
#include <limits.h>

#if DEVICE_MPU

static uint16_t mem_xn_lock;
static uint16_t mem_wn_lock;

void mbed_mpu_manager_lock_ram_execution()
{
core_util_critical_section_enter();
if (mem_xn_lock == USHRT_MAX) {
core_util_critical_section_exit();
MBED_ERROR1(MBED_MAKE_ERROR(MBED_MODULE_PLATFORM, MBED_ERROR_CODE_OVERFLOW), "Ram execute never lock overflow (> USHRT_MAX)", mem_xn_lock);
}
MBED_ASSERT(mem_xn_lock != USHRT_MAX);
if (mem_xn_lock == 0) {
mbed_mpu_enable_ram_xn(false);
}
Expand All @@ -40,10 +40,7 @@ void mbed_mpu_manager_lock_ram_execution()
void mbed_mpu_manager_unlock_ram_execution()
{
core_util_critical_section_enter();
if (mem_xn_lock == 0) {
core_util_critical_section_exit();
MBED_ERROR1(MBED_MAKE_ERROR(MBED_MODULE_PLATFORM, MBED_ERROR_CODE_UNDERFLOW), "Ram execute never lock underflow (< 0)", mem_xn_lock);
}
MBED_ASSERT(mem_xn_lock != 0);
mem_xn_lock--;
if (mem_xn_lock == 0) {
mbed_mpu_enable_ram_xn(true);
Expand All @@ -54,10 +51,7 @@ void mbed_mpu_manager_unlock_ram_execution()
void mbed_mpu_manager_lock_rom_write()
{
core_util_critical_section_enter();
if (mem_wn_lock == USHRT_MAX) {
core_util_critical_section_exit();
MBED_ERROR1(MBED_MAKE_ERROR(MBED_MODULE_PLATFORM, MBED_ERROR_CODE_OVERFLOW), "Rom write never lock overflow (> USHRT_MAX)", mem_wn_lock);
}
MBED_ASSERT(mem_wn_lock != USHRT_MAX);
if (mem_wn_lock == 0) {
mbed_mpu_enable_rom_wn(false);
}
Expand All @@ -68,13 +62,12 @@ void mbed_mpu_manager_lock_rom_write()
void mbed_mpu_manager_unlock_rom_write()
{
core_util_critical_section_enter();
if (mem_wn_lock == 0) {
core_util_critical_section_exit();
MBED_ERROR1(MBED_MAKE_ERROR(MBED_MODULE_PLATFORM, MBED_ERROR_CODE_UNDERFLOW), "Rom write never lock underflow (< 0)", mem_wn_lock);
}
MBED_ASSERT(mem_wn_lock != 0);
mem_wn_lock--;
if (mem_wn_lock == 0) {
mbed_mpu_enable_rom_wn(true);
}
core_util_critical_section_exit();
}

#endif
14 changes: 14 additions & 0 deletions platform/mbed_mpu_mgmt.h
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Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,8 @@
extern "C" {
#endif

#if DEVICE_MPU

/** Lock ram execute never mode off
*
* This disables the MPU's execute never ram protection and allows
Expand Down Expand Up @@ -80,6 +82,18 @@ void mbed_mpu_manager_lock_rom_write(void);
*/
void mbed_mpu_manager_unlock_rom_write(void);

#else

#define mbed_mpu_manager_lock_ram_execution() (void)0

#define mbed_mpu_manager_unlock_ram_execution() (void)0

#define mbed_mpu_manager_lock_rom_write() (void)0

#define mbed_mpu_manager_unlock_rom_write() (void)0

#endif

#ifdef __cplusplus
}
#endif
Expand Down
2 changes: 0 additions & 2 deletions rtos/TARGET_CORTEX/mbed_boot.c
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Expand Up @@ -89,8 +89,6 @@ uint32_t mbed_stack_isr_size = 0;
void mbed_init(void)
{
mbed_mpu_init();
mbed_mpu_enable_ram_xn(true);
mbed_mpu_enable_rom_wn(true);
mbed_cpy_nvic();
mbed_sdk_init();
mbed_rtos_init();
Expand Down