b2b88c5cb4
Global data (pointed by R2 on PowerPC) in principle is not guaranteed to be in proximity of U-Boot heap (where the API signature is placed) accross different architectures and platforms. Instead, use U-Boot stack pointer as a hint for the search instead of the global data; this method tends to be more uniform accross different platforms. Obtained from: Semihalf
95 lines
2.5 KiB
ArmAsm
95 lines
2.5 KiB
ArmAsm
/*-
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* Copyright (c) 2007 Semihalf, Rafal Jaworowski <raj@semihalf.com>
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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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lis %r11, uboot_address@ha
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addi %r11, %r11, uboot_address@l
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stw %r1, 0(%r11)
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/* Save U-Boot's r14 */
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lis %r11, saved_regs@ha
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addi %r11, %r11, saved_regs@l
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stw %r14, 0(%r11)
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/* Disable interrupts */
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mfmsr %r11
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andi. %r11, %r11, ~0x8000@l
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mtmsr %r11
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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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stwu %r1, -16(%r1)
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mflr %r0
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stw %r14, 8(%r1)
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stw %r0, 20(%r1)
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/* Restore U-Boot's r14 */
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lis %r11, saved_regs@ha
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addi %r11, %r11, saved_regs@l
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lwz %r14, 0(%r11)
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/* Enable interrupts */
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mfmsr %r11
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ori %r11, %r11, 0x8000@l
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mtmsr %r11
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/* Call into U-Boot */
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lis %r11, syscall_ptr@ha
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addi %r11, %r11, syscall_ptr@l
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lwz %r11, 0(%r11)
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mtctr %r11
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bctrl
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/* Disable interrupts */
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mfmsr %r11
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andi. %r11, %r11, ~0x8000@l
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mtmsr %r11
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/* Epilogue */
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lwz %r11, 0(%r1)
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lwz %r0, 4(%r11)
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mtlr %r0
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lwz %r14, 8(%r1)
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mr %r1, %r11
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blr
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/*
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* Data section
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*/
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.data
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GLOBAL(syscall_ptr)
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.long 0
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GLOBAL(saved_regs)
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.long 0 /* R14 */
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GLOBAL(uboot_address)
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.long 0
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