87 lines
2.3 KiB
ArmAsm
87 lines
2.3 KiB
ArmAsm
/*-
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* Copyright (c) 2008 Semihalf, Rafal Czubak
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* All rights reserved.
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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
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* 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 AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <machine/asm.h>
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/*
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* Entry point to the loader that U-Boot passes control to.
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*/
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.text
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.globl _start
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_start:
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/* Hint where to look for the API signature */
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ldr ip, =uboot_address
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str sp, [ip]
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/* Save U-Boot's r8 */
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ldr ip, =saved_regs
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str r8, [ip, #0]
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/* Start loader */
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b main
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/*
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* syscall()
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*/
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ENTRY(syscall)
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/* Save caller's lr and r8 */
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ldr ip, =saved_regs
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str lr, [ip, #4]
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str r8, [ip, #8]
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/* Restore U-Boot's r8 */
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ldr r8, [ip, #0]
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/* Call into U-Boot */
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ldr lr, =return_from_syscall
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ldr ip, =syscall_ptr
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ldr pc, [ip]
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return_from_syscall:
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/* Restore loader's r8 and lr */
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ldr ip, =saved_regs
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ldr r8, [ip, #8]
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ldr lr, [ip, #4]
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/* Return to caller */
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mov pc, lr
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/*
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* Data section
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*/
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.data
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.align 4
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.globl syscall_ptr
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syscall_ptr:
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.long 0
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.globl uboot_address
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uboot_address:
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.long 0
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saved_regs:
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.long 0 /* U-Boot's r8 */
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.long 0 /* Loader's r8 */
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.long 0 /* Loader's lr */
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