/**************************************************************************** * arch/arm/src/armv6-m/up_initialstate.c * * Copyright (C) 2013 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 "up_internal.h" #include "up_arch.h" #include "psr.h" #include "exc_return.h" /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ /**************************************************************************** * Private Data ****************************************************************************/ /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: up_initial_state * * Description: * A new thread is being started and a new TCB * has been created. This function is called to initialize * the processor specific portions of the new TCB. * * This function must setup the intial architecture registers * and/or stack so that execution will begin at tcb->start * on the next context switch. * ****************************************************************************/ void up_initial_state(struct tcb_s *tcb) { struct xcptcontext *xcp = &tcb->xcp; /* Initialize the initial exception register context structure */ memset(xcp, 0, sizeof(struct xcptcontext)); /* Save the initial stack pointer */ xcp->regs[REG_SP] = (uint32_t)tcb->adj_stack_ptr; /* Save the task entry point (stripping off the thumb bit) */ xcp->regs[REG_PC] = (uint32_t)tcb->start & ~1; /* Specify thumb mode */ xcp->regs[REG_XPSR] = ARMV6M_XPSR_T; /* If this task is running PIC, then set the PIC base register to the * address of the allocated D-Space region. */ #ifdef CONFIG_PIC if (tcb->dspace != NULL) { /* Set the PIC base register (probably R10) to the address of the * alloacated D-Space region. */ xcp->regs[REG_PIC] = (uint32_t)tcb->dspace->region; } /* Make certain that bit 0 is set in the main entry address. This is * only an issue when NXFLAT is enabled. NXFLAT doesn't know anything * about thumb; the addresses that NXFLAT sets are based on file header * info and won't have bit 0 set. */ #ifdef CONFIG_NXFLAT tcb->entry.main = (main_t)((uint32_t)tcb->entry.main | 1); #endif #endif /* CONFIG_PIC */ /* Set privileged- or unprivileged-mode, depending on how NuttX is * configured and what kind of thread is being started. */ #ifdef CONFIG_NUTTX_KERNEL if ((tcb->flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_KERNEL) { /* It is a normal task or a pthread. Set user mode */ xcp->regs[REG_EXC_RETURN] = EXC_RETURN_UNPRIVTHR; } else #endif /* CONFIG_NUTTX_KERNEL */ { /* If the kernel build is not selected -OR- if this is a kernel * thread, then start it in privileged thread mode. */ xcp->regs[REG_EXC_RETURN] = EXC_RETURN_PRIVTHR; } /* Enable or disable interrupts, based on user configuration */ #ifdef CONFIG_SUPPRESS_INTERRUPTS xcp->regs[REG_BASEPRI] = NVIC_SYSH_DISABLE_PRIORITY; #endif /* CONFIG_SUPPRESS_INTERRUPTS */ }