Diff: mbed-os/platform/mbed_critical.c

Revision:

0:380207fcb5c1

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-os/platform/mbed_critical.c	Thu Mar 29 07:02:09 2018 +0000
@@ -0,0 +1,347 @@
+/*
+ * 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.
+ */
+
+/* Declare __STDC_LIMIT_MACROS so stdint.h defines UINT32_MAX when using C++ */
+#define __STDC_LIMIT_MACROS
+#include "hal/critical_section_api.h"
+
+#include "cmsis.h"
+#include "platform/mbed_assert.h"
+#include "platform/mbed_critical.h"
+#include "platform/mbed_toolchain.h"
+
+// if __EXCLUSIVE_ACCESS rtx macro not defined, we need to get this via own-set architecture macros
+#ifndef MBED_EXCLUSIVE_ACCESS
+#ifndef __EXCLUSIVE_ACCESS
+#if ((__ARM_ARCH_7M__      == 1U) || \
+    (__ARM_ARCH_7EM__     == 1U) || \
+    (__ARM_ARCH_8M_BASE__ == 1U) || \
+    (__ARM_ARCH_8M_MAIN__ == 1U)) || \
+    (__ARM_ARCH_7A__ == 1U)
+#define MBED_EXCLUSIVE_ACCESS      1U
+#elif (__ARM_ARCH_6M__ == 1U)
+#define MBED_EXCLUSIVE_ACCESS      0U
+#else
+#error "Unknown architecture for exclusive access"
+#endif
+#else 
+#define MBED_EXCLUSIVE_ACCESS __EXCLUSIVE_ACCESS
+#endif
+#endif
+
+static volatile uint32_t critical_section_reentrancy_counter = 0;
+
+bool core_util_are_interrupts_enabled(void)
+{
+#if defined(__CORTEX_A9)
+    return ((__get_CPSR() & 0x80) == 0);
+#else
+    return ((__get_PRIMASK() & 0x1) == 0);
+#endif
+}
+
+bool core_util_is_isr_active(void)
+{
+#if defined(__CORTEX_A9)
+    switch(__get_CPSR() & 0x1FU) {
+        case CPSR_M_USR:
+        case CPSR_M_SYS:
+            return false;
+        case CPSR_M_SVC:
+        default:
+            return true;
+    }
+#else
+    return (__get_IPSR() != 0U);
+#endif
+}
+
+bool core_util_in_critical_section(void)
+{
+    return hal_in_critical_section();
+}
+
+void core_util_critical_section_enter(void)
+{
+// FIXME
+#ifdef FEATURE_UVISOR
+    #warning "core_util_critical_section_enter needs fixing to work from unprivileged code"
+#else
+    // If the reentrancy counter overflows something has gone badly wrong.
+    MBED_ASSERT(critical_section_reentrancy_counter < UINT32_MAX);
+#endif /* FEATURE_UVISOR */
+
+    hal_critical_section_enter();
+
+    ++critical_section_reentrancy_counter;
+}
+
+void core_util_critical_section_exit(void)
+{
+// FIXME
+#ifdef FEATURE_UVISOR
+    #warning "core_util_critical_section_exit needs fixing to work from unprivileged code"
+#endif /* FEATURE_UVISOR */
+
+    // If critical_section_enter has not previously been called, do nothing
+    if (critical_section_reentrancy_counter == 0) {
+        return;
+    }
+
+    --critical_section_reentrancy_counter;
+
+    if (critical_section_reentrancy_counter == 0) {
+        hal_critical_section_exit();
+    }
+}
+
+#if MBED_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(volatile uint8_t *ptr, uint8_t *expectedCurrentValue, uint8_t desiredValue)
+{
+    do {
+        uint8_t currentValue = __LDREXB(ptr);
+        if (currentValue != *expectedCurrentValue) {
+            *expectedCurrentValue = currentValue;
+            __CLREX();
+            return false;
+        }
+    } while (__STREXB(desiredValue, ptr));
+    return true;
+}
+
+bool core_util_atomic_cas_u16(volatile uint16_t *ptr, uint16_t *expectedCurrentValue, uint16_t desiredValue)
+{
+    do {
+        uint16_t currentValue = __LDREXH(ptr);
+        if (currentValue != *expectedCurrentValue) {
+            *expectedCurrentValue = currentValue;
+            __CLREX();
+            return false;
+        }
+    } while (__STREXH(desiredValue, ptr));
+    return true;
+}
+
+
+bool core_util_atomic_cas_u32(volatile uint32_t *ptr, uint32_t *expectedCurrentValue, uint32_t desiredValue)
+{
+    do {
+        uint32_t currentValue = __LDREXW(ptr);
+        if (currentValue != *expectedCurrentValue) {
+            *expectedCurrentValue = currentValue;
+            __CLREX();
+            return false;
+        }
+    } while (__STREXW(desiredValue, ptr));
+    return true;
+}
+
+uint8_t core_util_atomic_incr_u8(volatile uint8_t *valuePtr, uint8_t delta)
+{
+    uint8_t newValue;
+    do {
+        newValue = __LDREXB(valuePtr) + delta;
+    } while (__STREXB(newValue, valuePtr));
+    return newValue;
+}
+
+uint16_t core_util_atomic_incr_u16(volatile uint16_t *valuePtr, uint16_t delta)
+{
+    uint16_t newValue;
+    do {
+        newValue = __LDREXH(valuePtr) + delta;
+    } while (__STREXH(newValue, valuePtr));
+    return newValue;
+}
+
+uint32_t core_util_atomic_incr_u32(volatile uint32_t *valuePtr, uint32_t delta)
+{
+    uint32_t newValue;
+    do {
+        newValue = __LDREXW(valuePtr) + delta;
+    } while (__STREXW(newValue, valuePtr));
+    return newValue;
+}
+
+
+uint8_t core_util_atomic_decr_u8(volatile uint8_t *valuePtr, uint8_t delta)
+{
+    uint8_t newValue;
+    do {
+        newValue = __LDREXB(valuePtr) - delta;
+    } while (__STREXB(newValue, valuePtr));
+    return newValue;
+}
+
+uint16_t core_util_atomic_decr_u16(volatile uint16_t *valuePtr, uint16_t delta)
+{
+    uint16_t newValue;
+    do {
+        newValue = __LDREXH(valuePtr) - delta;
+    } while (__STREXH(newValue, valuePtr));
+    return newValue;
+}
+
+uint32_t core_util_atomic_decr_u32(volatile uint32_t *valuePtr, uint32_t delta)
+{
+    uint32_t newValue;
+    do {
+        newValue = __LDREXW(valuePtr) - delta;
+    } while (__STREXW(newValue, valuePtr));
+    return newValue;
+}
+
+#else
+
+bool core_util_atomic_cas_u8(volatile 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(volatile 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(volatile 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(volatile 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(volatile 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(volatile 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(volatile 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(volatile 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(volatile 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 * volatile *ptr, void **expectedCurrentValue, void *desiredValue) {
+    return core_util_atomic_cas_u32(
+            (volatile uint32_t *)ptr,
+            (uint32_t *)expectedCurrentValue,
+            (uint32_t)desiredValue);
+}
+
+void *core_util_atomic_incr_ptr(void * volatile *valuePtr, ptrdiff_t delta) {
+    return (void *)core_util_atomic_incr_u32((volatile uint32_t *)valuePtr, (uint32_t)delta);
+}
+
+void *core_util_atomic_decr_ptr(void * volatile *valuePtr, ptrdiff_t delta) {
+    return (void *)core_util_atomic_decr_u32((volatile uint32_t *)valuePtr, (uint32_t)delta);
+}
+