209 lines
5.1 KiB
ArmAsm
209 lines
5.1 KiB
ArmAsm
/* -*-Asm-*- */
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/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2009 Free Software Foundation, Inc.
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*
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <grub/boot.h>
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#include <grub/machine/boot.h>
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.text
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.align 4
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.globl _start
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_start:
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/* OF CIF entry point arrives in %o4 */
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pic_base:
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call boot_continue
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mov %o4, CIF_REG
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. = _start + GRUB_BOOT_MACHINE_VER_MAJ
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boot_version: .byte GRUB_BOOT_VERSION_MAJOR, GRUB_BOOT_VERSION_MINOR
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/* The offsets to these locations are defined by the
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* GRUB_BOOT_MACHINE_foo macros in include/grub/sparc/ieee1275/boot.h,
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* and grub-setup uses this to patch these next three values as needed.
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*
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* The boot_path will be the OF device path of the partition where the
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* rest of the GRUB kernel image resides. kernel_sector will be set to
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* the location of the first block of the GRUB kernel, and
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* kernel_address is the location where we should load that first block.
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*
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* After loading in that block we will execute it by jumping to the
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* load address plus the size of the prepended A.OUT header (32 bytes).
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*/
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boot_path:
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. = _start + GRUB_BOOT_MACHINE_KERNEL_BYTE
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boot_path_end:
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kernel_byte: .xword (2 << 9)
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kernel_address: .word GRUB_BOOT_MACHINE_KERNEL_ADDR
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prom_finddev_name: .asciz "finddevice"
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prom_chosen_path: .asciz "/chosen"
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prom_getprop_name: .asciz "getprop"
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prom_stdout_name: .asciz "stdout"
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prom_write_name: .asciz "write"
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prom_bootpath_name: .asciz "bootpath"
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prom_open_name: .asciz "open"
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prom_seek_name: .asciz "seek"
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prom_read_name: .asciz "read"
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prom_exit_name: .asciz "exit"
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grub_name: .asciz "GRUB "
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#define GRUB_NAME_LEN 5
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.align 4
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prom_open_error:
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GET_ABS(prom_open_name, %o2)
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call console_write
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mov 4, %o3
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/* fallthru */
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prom_error:
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GET_ABS(prom_exit_name, %o0)
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/* fallthru */
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/* %o0: OF call name
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* %o1: input arg 1
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*/
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prom_call_1_1_o2:
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clr %o2
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ba prom_call_x_1
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mov 1, %g1
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prom_call_getprop:
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mov 4, %g1
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stx %g1, [%l1 + 256]
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mov CHOSEN_NODE_REG, %o1
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ba prom_call_x_1
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GET_ABS(prom_getprop_name, %o0)
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prom_call_3_1_o1:
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ba prom_call_3_1
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mov BOOTDEV_REG, %o1
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/* %o2: message string
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* %o3: message length
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*/
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console_write:
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GET_ABS(prom_write_name, %o0)
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mov STDOUT_NODE_REG, %o1
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/* fallthru */
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/* %o0: OF call name
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* %o1: input arg 1
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* %o2: input arg 2
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* %o3: input arg 3
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*/
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prom_call_3_1:
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mov 3, %g1
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prom_call_x_1:
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mov 1, %o5
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/* fallthru */
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/* %o0: OF call name
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* %g1: num inputs
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* %o5: num outputs
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* %o1-%o4: inputs
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*/
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prom_call:
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stx %o0, [%l1 + 0x00]
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stx %g1, [%l1 + 0x08]
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stx %o5, [%l1 + 0x10]
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stx %o1, [%l1 + 0x18]
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stx %o2, [%l1 + 0x20]
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stx %o3, [%l1 + 0x28]
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stx %o4, [%l1 + 0x30]
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jmpl CIF_REG, %g0
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mov %l1, %o0
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boot_continue:
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mov %o7, PIC_REG /* PIC base */
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sethi %hi(SCRATCH_PAD_BOOT), %l1 /* OF argument slots */
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/* Find the /chosen node so we can fetch the stdout handle,
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* and thus perform console output.
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*
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* chosen_node = prom_finddevice("/chosen")
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*/
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GET_ABS(prom_finddev_name, %o0)
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call prom_call_1_1_o2
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GET_ABS(prom_chosen_path, %o1)
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ldx [%l1 + 0x20], CHOSEN_NODE_REG
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brz CHOSEN_NODE_REG, prom_error
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/* getprop(chosen_node, "stdout", &buffer, buffer_size) */
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GET_ABS(prom_stdout_name, %o2)
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add %l1, 256, %o3
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call prom_call_getprop
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mov 1024, %o4
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lduw [%l1 + 256], STDOUT_NODE_REG
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brz,pn STDOUT_NODE_REG, prom_error
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/* write(stdout_node, "GRUB ", strlen("GRUB ")) */
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GET_ABS(grub_name, %o2)
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call console_write
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mov GRUB_NAME_LEN, %o3
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GET_ABS(boot_path, %o3)
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ldub [%o3], %o1
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brnz,pn %o1, bootpath_known
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/* getprop(chosen_node, "bootpath", &buffer, buffer_size) */
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GET_ABS(prom_bootpath_name, %o2)
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call prom_call_getprop
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mov (boot_path_end - boot_path), %o4
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bootpath_known:
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/* Open up the boot_path, and use that handle to read the
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* first block of the GRUB kernel image.
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*
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* bootdev_handle = open(boot_path)
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*/
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GET_ABS(prom_open_name, %o0)
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call prom_call_1_1_o2
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GET_ABS(boot_path, %o1)
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ldx [%l1 + 0x20], BOOTDEV_REG
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brz,pn BOOTDEV_REG, prom_open_error
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/* Since we have 64-bit cells, the high cell of the seek offset
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* is zero and the low cell is the entire value.
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*
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* seek(bootdev, 0, *kernel_byte)
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*/
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GET_ABS(prom_seek_name, %o0)
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clr %o2
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call prom_call_3_1_o1
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LDX_ABS(kernel_byte, 0x00, %o3)
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/* read(bootdev, *kernel_address, 512) */
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GET_ABS(prom_read_name, %o0)
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LDUW_ABS(kernel_address, 0x00, %o2)
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call prom_call_3_1_o1
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mov 512, %o3
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LDUW_ABS(kernel_address, 0x00, %o2)
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jmpl %o2, %o7
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nop
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. = _start + GRUB_BOOT_MACHINE_CODE_END
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/* the last 4 bytes in the sector 0 contain the signature */
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.word GRUB_BOOT_MACHINE_SIGNATURE
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