/**************************************************************************** * arch/arm/src/cortexm3/up_svcall.c * * Copyright (C) 2009 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the name NuttX nor the names of its contributors may be * used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include "os_internal.h" #include "up_internal.h" /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ #undef DEBUG_SVCALL /* Define to debug SVCall */ /**************************************************************************** * Private Data ****************************************************************************/ /**************************************************************************** * Public Data ****************************************************************************/ /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: up_svcall * * Description: * This is SVCall exception handler that performs context switching * ****************************************************************************/ int up_svcall(int irq, FAR void *context) { uint32 *regs = (uint32*)context; DEBUGASSERT(regs && regs == current_regs); DEBUGASSERT(regs[REG_R1] != 0); /* The SVCall software interrupt is called with R0 = SVC command and R1 = * the TCB register save area. */ sllvdbg("Command: %d regs: %p R1: %08x R2: %08x\n", regs[REG_R0], regs, regs[REG_R1], regs[REG_R2]); #ifdef DEBUG_SVCALL lldbg("SVCall Entry:\n"); lldbg(" R0: %08x %08x %08x %08x %08x %08x %08x %08x\n", regs[REG_R0], regs[REG_R1], regs[REG_R2], regs[REG_R3], regs[REG_R4], regs[REG_R5], regs[REG_R6], regs[REG_R7]); lldbg(" R8: %08x %08x %08x %08x %08x %08x %08x %08x\n", regs[REG_R8], regs[REG_R9], regs[REG_R10], regs[REG_R11], regs[REG_R12], regs[REG_R13], regs[REG_R14], regs[REG_R15]); lldbg(" PSR=%08x\n", regs[REG_XPSR]); #endif /* Handle the SVCall according to the command in R0 */ switch (regs[REG_R0]) { /* R0=0: This is a save context command: * * int up_saveusercontext(uint32 *saveregs); * * At this point, the following values are saved in context: * * R0 = 0 * R1 = saveregs * * In this case, we simply need to copy the current regsters to the * save regiser space references in the saved R1 and return. */ case 0: { memcpy((uint32*)regs[REG_R1], regs, XCPTCONTEXT_SIZE); } break; /* R0=1: This a restore context command: * * void up_fullcontextrestore(uint32 *restoreregs) __attribute__ ((noreturn)); * * At this point, the following values are saved in context: * * R0 = 1 * R1 = restoreregs * * In this case, we simply need to set current_regs to restore register * area referenced in the saved R1. context == current_regs is the normal * exception return. By setting current_regs = context[R1], we force * the return to the saved context referenced in R1. */ case 1: { current_regs = (uint32*)regs[REG_R1]; } break; /* R0=2: This a switch context command: * * void up_switchcontext(uint32 *saveregs, uint32 *restoreregs); * * At this point, the following values are saved in context: * * R0 = 1 * R1 = saveregs * R2 = restoreregs * * In this case, we do both: We save the context registers to the save * register area reference by the saved contents of R1 nad then set * current_regs to to the save register area referenced by the saved * contents of R2. */ case 2: { DEBUGASSERT(regs[REG_R2] != 0); memcpy((uint32*)regs[REG_R1], regs, XCPTCONTEXT_SIZE); current_regs = (uint32*)regs[REG_R2]; } break; default: PANIC(OSERR_INTERNAL); break; } #ifdef DEBUG_SVCALL lldbg("SVCall Return:\n"); lldbg(" R0: %08x %08x %08x %08x %08x %08x %08x %08x\n", current_regs[REG_R0], current_regs[REG_R1], current_regs[REG_R2], current_regs[REG_R3], current_regs[REG_R4], current_regs[REG_R5], current_regs[REG_R6], current_regs[REG_R7]); lldbg(" R8: %08x %08x %08x %08x %08x %08x %08x %08x\n", current_regs[REG_R8], current_regs[REG_R9], current_regs[REG_R10], current_regs[REG_R11], current_regs[REG_R12], current_regs[REG_R13], current_regs[REG_R14], current_regs[REG_R15]); lldbg(" PSR=%08x\n", current_regs[REG_XPSR]); #endif return OK; }