cpu/arm/__aeabi_read_tp.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /**
0004  * @file
0005  *
0006  * @ingroup RTEMSScoreCPUARM
0007  *
0008  * @brief This source file contains the implementation of __aeabi_read_tp().
0009  */
0010
0011 /*
0012  * Copyright (c) 2014 embedded brains GmbH & Co. KG
0013  *
0014  * Redistribution and use in source and binary forms, with or without
0015  * modification, are permitted provided that the following conditions
0016  * are met:
0017  * 1. Redistributions of source code must retain the above copyright
0018  *    notice, this list of conditions and the following disclaimer.
0019  * 2. Redistributions in binary form must reproduce the above copyright
0020  *    notice, this list of conditions and the following disclaimer in the
0021  *    documentation and/or other materials provided with the distribution.
0022  *
0023  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0024  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0025  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0026  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0027  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0028  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0029  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0030  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0031  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0032  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0033  * POSSIBILITY OF SUCH DAMAGE.
0034  */
0035
0036 #ifdef HAVE_CONFIG_H
0037 #include "config.h"
0038 #endif
0039
0040 #include <rtems/score/thread.h>
0041 #include <rtems/score/percpu.h>
0042
0043 #ifndef RTEMS_SMP
0044
0045 void __attribute__((naked)) __aeabi_read_tp(void);
0046
0047 void __attribute__((naked)) __aeabi_read_tp(void)
0048 {
0049   __asm__ volatile (
0050     "ldr r0, =_Per_CPU_Information\n"
0051     "ldr r0, [r0, %[executingoff]]\n"
0052 #if defined(__thumb__) && !defined(__thumb2__)
0053     "add r0, %[threadidoff]\n"
0054     "ldr r0, [r0]\n"
0055 #else
0056     "ldr r0, [r0, %[threadidoff]]\n"
0057 #endif
0058     "bx lr\n"
0059     :
0060     : [executingoff] "I" (offsetof(Per_CPU_Control, executing)),
0061       [threadidoff] "I" (offsetof(Thread_Control, Registers.thread_id))
0062   );
0063 }
0064
0065 #endif /* RTEMS_SMP */