freebsd-skq/sys/boot/mips/uboot/start.S
Stanislav Galabov a1b701d82b This review aims at introducing ubldr (loader with U-Boot interface) for MIPS
(32 and 64-bit, LE and BE).
The changes were tested with QEMU's 'mips' target.

Most of the implementation was lifted from the ARM version, the appropriate
MIPS-specific things were implemented.

With these changes I am able to go all the way through the u-boot->ubldr->kernel
boot chain in QEMU on all combinations of bit-ness and endian-ness.

For the tests I've used FAT32 disk images (as FAT32 is supported by U-boot),
which include /boot/kernel/kernel and /boot/kernel/ubldr.bin

In U-boot I do:
fatload ide 0 <LOAD_ADDR> /boot/kernel/ubldr.bin; go <LOAD_ADDR>
where LOAD_ADDR is 80800000 for 32-bit and ffffffff80800000 for 64-bit

Then it's the usual ubldr that takes over and loads and starts a kernel.

Approved by:	adrian (mentor)
Sponsored by:	Smartcom - Bulgaria AD
Differential Revision:	https://reviews.freebsd.org/D5313
2016-02-29 07:47:04 +00:00

72 lines
1.8 KiB
ArmAsm

/*-
* Copyright (c) 2016 Stanislav Galabov
* 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.
*
* $FreeBSD$
*/
#include <machine/asm.h>
.text
.extern _C_LABEL(main)
.weak _DYNAMIC
/*
* Entry point to the loader that U-Boot passes control to.
*/
ENTRY(_start)
PTR_S sp, uboot_address
j main
nop
END(_start)
/*
* syscall()
*/
ENTRY(syscall)
PTR_S ra, ret_address
PTR_L t9, syscall_ptr
jalr t9
nop
PTR_L ra, ret_address
jr ra
nop
END(syscall)
/*
* Data section
*/
.data
.align 8
.globl syscall_ptr
syscall_ptr:
.dword 0
.globl uboot_address
uboot_address:
.dword 0
ret_address:
.dword 0