129 lines
4.1 KiB
ArmAsm
129 lines
4.1 KiB
ArmAsm
/* exc_exit.s - ARM CORTEX-M3 exception/interrupt exit API */
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/*
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* Copyright (c) 2013-2014 Wind River Systems, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1) Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* 2) Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* 3) Neither the name of Wind River Systems nor the names of its contributors
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* may be used to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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DESCRIPTION
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Provides functions for performing kernel handling when exiting exceptions or
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interrupts that are installed directly in the vector table (i.e. that are not
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wrapped around by _IsrWrapper()).
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*/
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#define _ASMLANGUAGE
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#include <nanok.h>
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#include <offsets.h>
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#include <toolchain.h>
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#include <nanokernel/cpu.h>
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_ASM_FILE_PROLOGUE
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GTEXT(_ExcExit)
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GTEXT(_IntExit)
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GDATA(_NanoKernel)
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#if CONFIG_GDB_INFO
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#define _EXIT_EXC_IF_FIBER_PREEMPTED beq _ExcExitWithGdbStub
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#else
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_EXIT_EXC_IF_FIBER_PREEMPTED: .macro
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it eq
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bxeq lr
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.endm
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#endif
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#define _EXIT_EXC_IF_FIBER_NOT_READY _EXIT_EXC_IF_FIBER_PREEMPTED
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/*******************************************************************************
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*
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* _IntExit - kernel housekeeping when exiting interrupt handler installed
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* directly in vector table
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*
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* VxMicro allows installing interrupt handlers (ISRs) directly into the vector
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* table to get the lowest interrupt latency possible. This allows the ISR to be
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* invoked directly without going through a software interrupt table. However,
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* upon exiting the ISR, some kernel work must still be performed, namely
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* possible context switching. While ISRs connected in the software interrupt
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* table do this automatically via a wrapper, ISRs connected directly in the
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* vector table must invoke _IntExit() as the *very last* action before
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* returning.
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*
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* e.g.
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*
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* void myISR(void)
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* {
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* printk("in %s\n", __FUNCTION__);
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* doStuff();
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* _IntExit();
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* }
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*
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* RETURNS: N/A
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*/
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SECTION_SUBSEC_FUNC(TEXT, _HandlerModeExit, _IntExit)
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/* _IntExit falls through to _ExcExit (they are aliases of each other) */
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/*******************************************************************************
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*
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* _ExcExit - kernel housekeeping when exiting exception handler installed
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* directly in vector table
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*
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* See _IntExit().
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*
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* RETURNS: N/A
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*/
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SECTION_SUBSEC_FUNC(TEXT, _HandlerModeExit, _ExcExit)
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ldr r1, =_NanoKernel
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/* is the current thread preemptible (task) ? */
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ldr r2, [r1, #__tNANO_flags_OFFSET]
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ands.w r2, #PREEMPTIBLE
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_EXIT_EXC_IF_FIBER_PREEMPTED
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/* is there a fiber ready ? */
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ldr r2, [r1, #__tNANO_fiber_OFFSET]
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cmp r2, #0
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_EXIT_EXC_IF_FIBER_NOT_READY
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/* context switch required, pend the PendSV exception */
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ldr r1, =_SCS_ICSR
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ldr r2, =_SCS_ICSR_PENDSV
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str r2, [r1]
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_ExcExitWithGdbStub:
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_GDB_STUB_EXC_EXIT
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bx lr
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