FreeBSD/Linux Kernel Cross Reference
sys/arm/arm/stack_machdep.c

     /*-
      * Copyright (c) 2005 Antoine Brodin
      * All rights reserved.
      *
      * 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.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/10.2/sys/arm/arm/stack_machdep.c 278614 2015-02-12 04:15:55Z ian $");
    
    #include <sys/systm.h>
    #include <sys/param.h>
    #include <sys/proc.h>
    #include <sys/stack.h>
    
    #include <machine/vmparam.h>
    #include <machine/pcb.h>
    #include <machine/stack.h>
    
    /*
     * This code makes assumptions about the stack layout. These are correct
     * when using APCS (the old ABI), but are no longer true with AAPCS and the
     * ARM EABI. There is also an issue with clang and llvm when building for
     * APCS where it lays out the stack incorrectly. Because of this we disable
     * this when building for ARM EABI or when building with clang.
     */
    
    extern vm_offset_t kernel_vm_end;
    
    static void
    stack_capture(struct stack *st, u_int32_t *frame)
    {
    #if !defined(__ARM_EABI__) && !defined(__clang__)
            vm_offset_t callpc;
    
            while (INKERNEL(frame) && (vm_offset_t)frame < kernel_vm_end) {
                    callpc = frame[FR_SCP];
                    if (stack_put(st, callpc) == -1)
                            break;
                    frame = (u_int32_t *)(frame[FR_RFP]);
            }
    #endif
    }
    
    void
    stack_save_td(struct stack *st, struct thread *td)
    {
            u_int32_t *frame;
    
            if (TD_IS_SWAPPED(td))
                    panic("stack_save_td: swapped");
            if (TD_IS_RUNNING(td))
                    panic("stack_save_td: running");
    
            /*
             * This register, the frame pointer, is incorrect for the ARM EABI
             * as it doesn't have a frame pointer, however it's value is not used
             * when building for EABI.
             */
            frame = (u_int32_t *)td->td_pcb->pcb_regs.sf_r11;
            stack_zero(st);
            stack_capture(st, frame);
    }
    
    void
    stack_save(struct stack *st)
    {
            u_int32_t *frame;
    
            frame = (u_int32_t *)__builtin_frame_address(0);
            stack_zero(st);
            stack_capture(st, frame);
    }

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