mbed-os/platform/mbed_critical.c

321 lines
9.1 KiB
C

/*
* Copyright (c) 2015-2016, ARM Limited, All Rights Reserved
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "platform/critical.h"
#include "cmsis.h"
#include "platform/mbed_assert.h"
#include "platform/toolchain.h"
#define EXCLUSIVE_ACCESS (!defined (__CORTEX_M0) && !defined (__CORTEX_M0PLUS))
static volatile uint32_t interrupt_enable_counter = 0;
static volatile bool critical_interrupts_disabled = false;
bool core_util_are_interrupts_enabled(void)
{
#if defined(__CORTEX_A9)
return ((__get_CPSR() & 0x80) == 0);
#else
return ((__get_PRIMASK() & 0x1) == 0);
#endif
}
MBED_WEAK void core_util_critical_section_enter(void)
{
bool interrupts_disabled = !core_util_are_interrupts_enabled();
__disable_irq();
/* Save the interrupt disabled state as it was prior to any nested critical section lock use */
if (!interrupt_enable_counter) {
critical_interrupts_disabled = interrupts_disabled;
}
/* If the interrupt_enable_counter overflows or we are in a nested critical section and interrupts
are enabled, then something has gone badly wrong thus assert an error.
*/
MBED_ASSERT(interrupt_enable_counter < UINT32_MAX);
// FIXME
#ifndef FEATURE_UVISOR
if (interrupt_enable_counter > 0) {
MBED_ASSERT(interrupts_disabled);
}
#else
#warning "core_util_critical_section_enter needs fixing to work from unprivileged code"
#endif /* FEATURE_UVISOR */
interrupt_enable_counter++;
}
MBED_WEAK void core_util_critical_section_exit(void)
{
/* If critical_section_enter has not previously been called, do nothing */
if (interrupt_enable_counter) {
// FIXME
#ifndef FEATURE_UVISOR
bool interrupts_disabled = !core_util_are_interrupts_enabled(); /* get the current interrupt disabled state */
MBED_ASSERT(interrupts_disabled); /* Interrupts must be disabled on invoking an exit from a critical section */
#else
#warning "core_util_critical_section_exit needs fixing to work from unprivileged code"
#endif /* FEATURE_UVISOR */
interrupt_enable_counter--;
/* Only re-enable interrupts if we are exiting the last of the nested critical sections and
interrupts were enabled on entry to the first critical section.
*/
if (!interrupt_enable_counter && !critical_interrupts_disabled) {
__enable_irq();
}
}
}
#if EXCLUSIVE_ACCESS
/* Supress __ldrex and __strex deprecated warnings - "#3731-D: intrinsic is deprecated" */
#if defined (__CC_ARM)
#pragma diag_suppress 3731
#endif
bool core_util_atomic_cas_u8(uint8_t *ptr, uint8_t *expectedCurrentValue, uint8_t desiredValue)
{
uint8_t currentValue = __LDREXB((volatile uint8_t*)ptr);
if (currentValue != *expectedCurrentValue) {
*expectedCurrentValue = currentValue;
__CLREX();
return false;
}
return !__STREXB(desiredValue, (volatile uint8_t*)ptr);
}
bool core_util_atomic_cas_u16(uint16_t *ptr, uint16_t *expectedCurrentValue, uint16_t desiredValue)
{
uint16_t currentValue = __LDREXH((volatile uint16_t*)ptr);
if (currentValue != *expectedCurrentValue) {
*expectedCurrentValue = currentValue;
__CLREX();
return false;
}
return !__STREXH(desiredValue, (volatile uint16_t*)ptr);
}
bool core_util_atomic_cas_u32(uint32_t *ptr, uint32_t *expectedCurrentValue, uint32_t desiredValue)
{
uint32_t currentValue = __LDREXW((volatile uint32_t*)ptr);
if (currentValue != *expectedCurrentValue) {
*expectedCurrentValue = currentValue;
__CLREX();
return false;
}
return !__STREXW(desiredValue, (volatile uint32_t*)ptr);
}
uint8_t core_util_atomic_incr_u8(uint8_t *valuePtr, uint8_t delta)
{
uint8_t newValue;
do {
newValue = __LDREXB((volatile uint8_t*)valuePtr) + delta;
} while (__STREXB(newValue, (volatile uint8_t*)valuePtr));
return newValue;
}
uint16_t core_util_atomic_incr_u16(uint16_t *valuePtr, uint16_t delta)
{
uint16_t newValue;
do {
newValue = __LDREXH((volatile uint16_t*)valuePtr) + delta;
} while (__STREXH(newValue, (volatile uint16_t*)valuePtr));
return newValue;
}
uint32_t core_util_atomic_incr_u32(uint32_t *valuePtr, uint32_t delta)
{
uint32_t newValue;
do {
newValue = __LDREXW((volatile uint32_t*)valuePtr) + delta;
} while (__STREXW(newValue, (volatile uint32_t*)valuePtr));
return newValue;
}
uint8_t core_util_atomic_decr_u8(uint8_t *valuePtr, uint8_t delta)
{
uint8_t newValue;
do {
newValue = __LDREXB((volatile uint8_t*)valuePtr) - delta;
} while (__STREXB(newValue, (volatile uint8_t*)valuePtr));
return newValue;
}
uint16_t core_util_atomic_decr_u16(uint16_t *valuePtr, uint16_t delta)
{
uint16_t newValue;
do {
newValue = __LDREXH((volatile uint16_t*)valuePtr) - delta;
} while (__STREXH(newValue, (volatile uint16_t*)valuePtr));
return newValue;
}
uint32_t core_util_atomic_decr_u32(uint32_t *valuePtr, uint32_t delta)
{
uint32_t newValue;
do {
newValue = __LDREXW((volatile uint32_t*)valuePtr) - delta;
} while (__STREXW(newValue, (volatile uint32_t*)valuePtr));
return newValue;
}
#else
bool core_util_atomic_cas_u8(uint8_t *ptr, uint8_t *expectedCurrentValue, uint8_t desiredValue)
{
bool success;
uint8_t currentValue;
core_util_critical_section_enter();
currentValue = *ptr;
if (currentValue == *expectedCurrentValue) {
*ptr = desiredValue;
success = true;
} else {
*expectedCurrentValue = currentValue;
success = false;
}
core_util_critical_section_exit();
return success;
}
bool core_util_atomic_cas_u16(uint16_t *ptr, uint16_t *expectedCurrentValue, uint16_t desiredValue)
{
bool success;
uint16_t currentValue;
core_util_critical_section_enter();
currentValue = *ptr;
if (currentValue == *expectedCurrentValue) {
*ptr = desiredValue;
success = true;
} else {
*expectedCurrentValue = currentValue;
success = false;
}
core_util_critical_section_exit();
return success;
}
bool core_util_atomic_cas_u32(uint32_t *ptr, uint32_t *expectedCurrentValue, uint32_t desiredValue)
{
bool success;
uint32_t currentValue;
core_util_critical_section_enter();
currentValue = *ptr;
if (currentValue == *expectedCurrentValue) {
*ptr = desiredValue;
success = true;
} else {
*expectedCurrentValue = currentValue;
success = false;
}
core_util_critical_section_exit();
return success;
}
uint8_t core_util_atomic_incr_u8(uint8_t *valuePtr, uint8_t delta)
{
uint8_t newValue;
core_util_critical_section_enter();
newValue = *valuePtr + delta;
*valuePtr = newValue;
core_util_critical_section_exit();
return newValue;
}
uint16_t core_util_atomic_incr_u16(uint16_t *valuePtr, uint16_t delta)
{
uint16_t newValue;
core_util_critical_section_enter();
newValue = *valuePtr + delta;
*valuePtr = newValue;
core_util_critical_section_exit();
return newValue;
}
uint32_t core_util_atomic_incr_u32(uint32_t *valuePtr, uint32_t delta)
{
uint32_t newValue;
core_util_critical_section_enter();
newValue = *valuePtr + delta;
*valuePtr = newValue;
core_util_critical_section_exit();
return newValue;
}
uint8_t core_util_atomic_decr_u8(uint8_t *valuePtr, uint8_t delta)
{
uint8_t newValue;
core_util_critical_section_enter();
newValue = *valuePtr - delta;
*valuePtr = newValue;
core_util_critical_section_exit();
return newValue;
}
uint16_t core_util_atomic_decr_u16(uint16_t *valuePtr, uint16_t delta)
{
uint16_t newValue;
core_util_critical_section_enter();
newValue = *valuePtr - delta;
*valuePtr = newValue;
core_util_critical_section_exit();
return newValue;
}
uint32_t core_util_atomic_decr_u32(uint32_t *valuePtr, uint32_t delta)
{
uint32_t newValue;
core_util_critical_section_enter();
newValue = *valuePtr - delta;
*valuePtr = newValue;
core_util_critical_section_exit();
return newValue;
}
#endif
bool core_util_atomic_cas_ptr(void **ptr, void **expectedCurrentValue, void *desiredValue) {
return core_util_atomic_cas_u32(
(uint32_t *)ptr,
(uint32_t *)expectedCurrentValue,
(uint32_t)desiredValue);
}
void *core_util_atomic_incr_ptr(void **valuePtr, ptrdiff_t delta) {
return (void *)core_util_atomic_incr_u32((uint32_t *)valuePtr, (uint32_t)delta);
}
void *core_util_atomic_decr_ptr(void **valuePtr, ptrdiff_t delta) {
return (void *)core_util_atomic_decr_u32((uint32_t *)valuePtr, (uint32_t)delta);
}