/**************************************************************************** * arch/arm/src/armv7-a/arm_dataabort.c * * Copyright (C) 2013, 2016 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 "sched/sched.h" #include "up_internal.h" #ifdef CONFIG_PAGING # include # include "arm.h" #endif /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: arm_dataabort * * Input Parameters: * regs - The standard, ARM register save array. * * If CONFIG_PAGING is selected in the NuttX configuration file, then these * additional input values are expected: * * dfar - Fault address register. On a data abort, the ARM MMU places the * miss virtual address (MVA) into the DFAR register. This is the address * of the data which, when accessed, caused the fault. * dfsr - Fault status register. On a data a abort, the ARM MMU places an * encoded four-bit value, the fault status, along with the four-bit * encoded domain number, in the data DFSR * * Description: * This is the data abort exception handler. The ARM data abort exception * occurs when a memory fault is detected during a data transfer. * ****************************************************************************/ #ifdef CONFIG_PAGING uint32_t *arm_dataabort(uint32_t *regs, uint32_t dfar, uint32_t dfsr) { struct tcb_s *tcb = this_task(); uint32_t *savestate; /* Save the saved processor context in CURRENT_REGS where it can be accessed * for register dumps and possibly context switching. */ savestate = (uint32_t *)CURRENT_REGS; CURRENT_REGS = regs; /* In the NuttX on-demand paging implementation, only the read-only, .text * section is paged. However, the ARM compiler generated PC-relative data * fetches from within the .text sections. Also, it is customary to locate * read-only data (.rodata) within the same section as .text so that it * does not require copying to RAM. Misses in either of these case should * cause a data abort. * * We are only interested in data aborts due to page translations faults. * Sections should already be in place and permissions should already be * be set correctly (to read-only) so any other data abort reason is a * fatal error. */ pginfo("DFSR: %08x DFAR: %08x\n", dfsr, dfar); if ((dfsr & FSR_MASK) != FSR_PAGE) { goto segfault; } /* Check the (virtual) address of data that caused the data abort. When * the exception occurred, this address was provided in the DFAR register. * (It has not yet been saved in the register context save area). */ pginfo("VBASE: %08x VEND: %08x\n", PG_PAGED_VBASE, PG_PAGED_VEND); if (dfar < PG_PAGED_VBASE || dfar >= PG_PAGED_VEND) { goto segfault; } /* Save the offending data address as the fault address in the TCB of * the currently task. This fault address is also used by the prefetch * abort handling; this will allow common paging logic for both * prefetch and data aborts. */ tcb->xcp.dfar = regs[REG_R15]; /* Call pg_miss() to schedule the page fill. A consequences of this * call are: * * (1) The currently executing task will be blocked and saved on * on the g_waitingforfill task list. * (2) An interrupt-level context switch will occur so that when * this function returns, it will return to a different task, * most likely the page fill worker thread. * (3) The page fill worker task has been signalled and should * execute immediately when we return from this exception. */ pg_miss(); /* Restore the previous value of CURRENT_REGS. NULL would indicate that * we are no longer in an interrupt handler. It will be non-NULL if we * are returning from a nested interrupt. */ CURRENT_REGS = savestate; return regs; segfault: _alert("Data abort. PC: %08x DFAR: %08x DFSR: %08x\n", regs[REG_PC], dfar, dfsr); PANIC(); return regs; /* To keep the compiler happy */ } #else /* CONFIG_PAGING */ uint32_t *arm_dataabort(uint32_t *regs, uint32_t dfar, uint32_t dfsr) { /* Save the saved processor context in CURRENT_REGS where it can be accessed * for register dumps and possibly context switching. */ CURRENT_REGS = regs; /* Crash -- possibly showing diagnostic debug information. */ _alert("Data abort. PC: %08x DFAR: %08x DFSR: %08x\n", regs[REG_PC], dfar, dfsr); PANIC(); return regs; /* To keep the compiler happy */ } #endif /* CONFIG_PAGING */