pebble/src/libos/include/mcu/privilege_arm.inl.h
2025-01-27 11:38:16 -08:00

37 lines
1.4 KiB
C

/*
* Copyright 2024 Google LLC
*
* 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.
*/
#define CMSIS_COMPATIBLE
#include <mcu.h>
//! @file privilege_arm.inl.h
//! Helpful functions for dealing with our micros execution state.
//!
//! Functions in this file muck with the control register. This register is described here:
//! http://infocenter.arm.com/help/topic/com.arm.doc.dui0552a/DUI0552A_cortex_m3_dgug.pdf page 2-9
//! We only really care about the 0th bit.
//! [0] nPriv Defines the Thread mode privilege level
//! 0 = Privileged
//! 1 = Unprivileged
//! This variable can be read in both modes, but only may be written in privileged mode.
// See http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0552a/CHDIGFCA.html
// for a more detailed explanation of these various privilege states.
static inline bool mcu_state_is_thread_privileged(void) {
return (__get_CONTROL() & 0x1) == 0;
}