mirror of
https://github.com/memtest86plus/memtest86plus.git
synced 2024-11-23 08:26:23 -06:00
396 lines
8.2 KiB
ArmAsm
396 lines
8.2 KiB
ArmAsm
// SPDX-License-Identifier: GPL-2.0
|
|
//
|
|
// setup.S collects the memory map information from the BIOS, disables APM,
|
|
// enables A20, and performs the switch from real mode to protected mode
|
|
// before jumping to the main program entry point.
|
|
//
|
|
// The memory map information is stored in the 4KB block of memory immediately
|
|
// following the setup code. The layout of the information matches the Linux
|
|
// boot_params struct. A pointer to this block is passed to the main program,
|
|
// for compatiblity with the Linux 32-bit boot protocol.
|
|
//
|
|
// Copyright (C) 2020-2021 Martin Whitaker.
|
|
//
|
|
// Derived from memtest86+ setup.S and head.S:
|
|
//
|
|
// 1-Jan-96 Modified by Chris Brady for use as a boot/loader for memtest-86.
|
|
|
|
#define __ASSEMBLY__
|
|
|
|
#include "boot.h"
|
|
#include "build_version.h"
|
|
|
|
#define BOOT_PARAMS_START (SETUP_SECS * 512)
|
|
#define BOOT_PARAMS_END (BOOT_PARAMS_START + 4096)
|
|
|
|
.section ".setup", "ax", @progbits
|
|
.code16
|
|
|
|
# Emulate the Linux boot header, to allow loading by other boot loaders.
|
|
# Indicate that the main program code should be loaded in high memory.
|
|
# bootsect.S will fix up the values if we are booted directly from the BIOS.
|
|
|
|
.globl setup
|
|
setup:
|
|
jmp do_setup
|
|
header:
|
|
.ascii "HdrS"
|
|
version:
|
|
.word 0x020c
|
|
realmode_swtch:
|
|
.long 0
|
|
start_sys_seg:
|
|
.word 0x1000
|
|
kernel_version:
|
|
.word mt86plus_version-512
|
|
type_of_loader:
|
|
.byte 0
|
|
loadflags:
|
|
.byte 0x1 # LOADED_HIGH
|
|
setup_move_size:
|
|
.word 0
|
|
.globl code32_start
|
|
code32_start:
|
|
.long HIGH_LOAD_ADDR
|
|
ramdisk_image:
|
|
.long 0
|
|
ramdisk_size:
|
|
.long 0
|
|
bootsect_kludge:
|
|
.long 0
|
|
heap_end_ptr:
|
|
.word 0
|
|
ext_loader_ver:
|
|
.byte 0
|
|
ext_loader_type:
|
|
.byte 0
|
|
cmd_line_ptr:
|
|
.long 0
|
|
initrd_addr_max:
|
|
.long 0xffffffff
|
|
kernel_alignment:
|
|
.long 4096
|
|
relocatable_kernel:
|
|
.byte 0
|
|
min_alignment:
|
|
.byte 12
|
|
xload_flags:
|
|
#ifdef __x86_64__
|
|
.word 0x9 # XLF_KERNEL_64,XLF_EFI_HANDOVER_64
|
|
#else
|
|
.word 0x4 # XLF_EFI_HANDOVER_32
|
|
#endif
|
|
cmd_line_size:
|
|
.long 255
|
|
hardware_subarch:
|
|
.long 0
|
|
hardware_subarch_data:
|
|
.quad 0
|
|
payload_offset:
|
|
.long 0
|
|
payload_length:
|
|
.long 0
|
|
setup_data:
|
|
.quad 0
|
|
pref_address:
|
|
.quad HIGH_LOAD_ADDR
|
|
init_size:
|
|
.long _init_size
|
|
handover_offset:
|
|
.long 0x10
|
|
|
|
do_setup:
|
|
# Reload the segment registers, except for the stack.
|
|
|
|
movw %cs, %ax
|
|
movw %ax, %ds
|
|
movw %ax, %es
|
|
|
|
# Get the memory map and disable APM.
|
|
|
|
call get_mem_info
|
|
call disable_apm
|
|
|
|
# Disable interrupts.
|
|
|
|
cli
|
|
movb $0x80, %al # disable NMI
|
|
outb %al, $0x70
|
|
|
|
# Enable A20.
|
|
|
|
# Try to switch using the fast A20 gate.
|
|
movw $0x92, %dx
|
|
inb %dx, %al
|
|
# Skip if it's unimplemented (read returns 0xff).
|
|
cmpb $0xff, %al
|
|
jz 0f
|
|
orb $0x02, %al # set the ALT_A20_GATE bit
|
|
andb $0xfe, %al # clear the INIT_NOW bit
|
|
outb %al, %dx
|
|
0:
|
|
# Use the keyboard controller method anyway.
|
|
call empty_8042
|
|
movb $0xd1, %al # send write command
|
|
outb %al, $0x64
|
|
call empty_8042
|
|
movb $0xdf, %al # A20 on
|
|
outb %al, $0x60
|
|
call empty_8042
|
|
|
|
# Set up a minimal GDT and IDT.
|
|
|
|
xorl %eax, %eax
|
|
movw %cs, %ax
|
|
shll $4, %eax
|
|
addl %eax, gdt_descr - setup + 2
|
|
lgdt gdt_descr - setup
|
|
lidt idt_descr - setup
|
|
|
|
# Load a pointer to the boot_params block into ESI.
|
|
|
|
xorl %esi, %esi
|
|
movw %cs, %si
|
|
shll $4, %esi
|
|
addl $BOOT_PARAMS_START, %esi
|
|
|
|
# Fix up the jump address.
|
|
|
|
movl (code32_start - setup), %eax
|
|
movl %eax, (jump - setup + 2)
|
|
|
|
# Copy code32_start to the boot_params struct.
|
|
|
|
movl %eax, (BOOT_PARAMS_START + 0x214)
|
|
|
|
# Copy cmd_line_ptr and cmd_line_size to the boot_params struct.
|
|
|
|
movl (cmd_line_ptr - setup), %eax
|
|
movl %eax, (BOOT_PARAMS_START + 0x228)
|
|
movl (cmd_line_size - setup), %eax
|
|
movl %eax, (BOOT_PARAMS_START + 0x238)
|
|
|
|
# Switch to protected mode.
|
|
|
|
movl %cr0, %eax
|
|
orl $1, %eax
|
|
movl %eax, %cr0
|
|
jmp flush
|
|
flush:
|
|
# Reload the segment registers and jump to the main test program.
|
|
|
|
movw $KERNEL_DS, %ax
|
|
movw %ax, %ds
|
|
movw %ax, %es
|
|
movw %ax, %ss
|
|
movw %ax, %fs
|
|
movw %ax, %gs
|
|
jump:
|
|
data32 ljmp $KERNEL_CS, $0
|
|
|
|
|
|
# This subroutine queries the BIOS to determine the system memory map
|
|
# and stores the results in the boot_params structure that we pass to
|
|
# the startup code.
|
|
|
|
#define SMAP 0x534d4150
|
|
|
|
get_mem_info:
|
|
push %ds
|
|
push %es
|
|
|
|
# Set DS and ES to point to the start of the boot_params structure.
|
|
|
|
movw %ds, %ax
|
|
addw $(BOOT_PARAMS_START >> 4), %ax
|
|
movw %ax, %ds
|
|
movw %ax, %es
|
|
|
|
# Zero the entire boot_params structure.
|
|
|
|
movw $0x0000, %di
|
|
movw $0x0400, %cx
|
|
xorl %eax, %eax
|
|
cld
|
|
rep stosl
|
|
|
|
# First try method E820. E820 returns memory classified into a whole
|
|
# bunch of different types, and allows memory holes and everything.
|
|
|
|
mem_e820:
|
|
movw $E820_MAP, %di # destination pointer
|
|
xorl %ebx, %ebx # continuation counter
|
|
|
|
loop_e820:
|
|
movl $0x0000e820, %eax # e820, upper word zeroed
|
|
movl $SMAP, %edx # ASCII 'SMAP'
|
|
movl $20, %ecx # size of the e820 record
|
|
int $0x15 # make the call
|
|
jc done_e820 # bail out if it fails
|
|
|
|
cmpl $SMAP, %eax # check the return is 'SMAP'
|
|
jne done_e820 # bail out if it fails
|
|
|
|
incb (E820_ENTRIES)
|
|
addw $E820_ENTRY_SIZE, %di
|
|
|
|
movb (E820_ENTRIES), %al # check for table full
|
|
cmpb $E820_MAP_SIZE, %al
|
|
je done_e820
|
|
|
|
cmpl $0, %ebx # any more entries?
|
|
jne loop_e820
|
|
|
|
done_e820:
|
|
cmpb $0, (E820_ENTRIES)
|
|
jnz get_mem_done
|
|
|
|
# Next try method E801.
|
|
|
|
mem_e801:
|
|
stc # Fix to work around buggy BIOSs
|
|
xorw %cx,%cx # which don't clear/set carry on
|
|
xorw %dx,%dx # pass/error of e801h memory size
|
|
# call or merely pass cx,dx through
|
|
# without changing them.
|
|
movw $0xe801, %ax
|
|
int $0x15
|
|
jc mem_88
|
|
|
|
cmpw $0x0, %cx # Kludge to handle BIOSes which
|
|
jne 0f # report their extended memory in
|
|
cmpw $0x0, %dx # AX/BX rather than CX/DX. The spec
|
|
jne 0f # I have read seems to indicate that
|
|
movw %ax, %cx # AX/BX are more reasonable anyway.
|
|
movw %bx, %dx
|
|
0:
|
|
jmp fake_e820
|
|
|
|
# Finally try method 88.
|
|
|
|
mem_88:
|
|
movb $0x88, %ah
|
|
int $0x15
|
|
movw %ax, %cx
|
|
movw $0, %dx
|
|
|
|
fake_e820:
|
|
# Write entry for memory below 1MB.
|
|
movl $0x0, E820_ADDR(%di)
|
|
movl $0xa0000, E820_SIZE(%di)
|
|
movl $1, E820_TYPE(%di)
|
|
incb (E820_ENTRIES)
|
|
addw $E820_ENTRY_SIZE, %di
|
|
|
|
# Write entry for memory between 1MB and 16MB.
|
|
|
|
andl $0xffff, %ecx # convert to 32-bits
|
|
jz 0f
|
|
shll $10, %ecx # convert to bytes
|
|
movl $0x100000, E820_ADDR(%di)
|
|
movl %ecx, E820_SIZE(%di)
|
|
movl $1, E820_TYPE(%di)
|
|
incb (E820_ENTRIES)
|
|
addw $E820_ENTRY_SIZE, %di
|
|
0:
|
|
# Write entry for memory above 16MB.
|
|
|
|
andl $0xffff, %edx # convert to 32-bits
|
|
jz 1f
|
|
shll $16, %edx # convert to bytes
|
|
movl $0x1000000, E820_ADDR(%di)
|
|
movl %edx, E820_SIZE(%di)
|
|
movl $1, E820_TYPE(%di)
|
|
incb (E820_ENTRIES)
|
|
addw $E820_ENTRY_SIZE, %di
|
|
1:
|
|
|
|
get_mem_done:
|
|
pop %es
|
|
pop %ds
|
|
ret
|
|
|
|
# This subroutine disables APM if it is present.
|
|
|
|
disable_apm:
|
|
movw $0x5300, %ax # APM BIOS installation check
|
|
xorw %bx, %bx
|
|
int $0x15
|
|
jc disable_apm_done # error -> no APM BIOS
|
|
|
|
cmpw $0x504d, %bx # check for "PM" signature
|
|
jne disable_apm_done # no signature -> no APM BIOS
|
|
|
|
movw $0x5304, %ax # Disconnect first just in case
|
|
xorw %bx, %bx
|
|
int $0x15 # ignore return code
|
|
|
|
movw $0x5301, %ax # Real Mode connect
|
|
xorw %bx, %bx
|
|
int $0x15
|
|
jc disable_apm_done # error
|
|
|
|
movw $0x5308, %ax # Disable APM
|
|
mov $0xffff, %bx
|
|
xorw %cx, %cx
|
|
int $0x15
|
|
|
|
disable_apm_done:
|
|
ret
|
|
|
|
# This subroutine checks that the keyboard command queue is empty (after
|
|
# emptying the output buffers). No timeout is used - if this hangs there
|
|
# is something wrong with the machine, and we probably couldn't proceed
|
|
# anyway.
|
|
|
|
empty_8042:
|
|
call delay
|
|
inb $0x64, %al # 8042 status port
|
|
cmpb $0xff, %al # skip if not implemented
|
|
jz empty_8042_ret
|
|
testb $1, %al # anything in the output buffer?
|
|
jz no_output
|
|
call delay
|
|
inb $0x60, %al # read it
|
|
jmp empty_8042
|
|
|
|
no_output:
|
|
testb $2, %al # is input buffer full?
|
|
jnz empty_8042 # yes - loop
|
|
empty_8042_ret:
|
|
ret
|
|
|
|
# This subroutine provides a short delay.
|
|
|
|
delay:
|
|
.word 0x00eb # jmp $+2
|
|
ret
|
|
|
|
# A minimal GDT and IDT.
|
|
|
|
.align 4
|
|
gdt:
|
|
.quad 0x0000000000000000 # NULL descriptor
|
|
.quad 0x0000000000000000 # not used
|
|
.quad 0x00c09a0000007fff # 128MB 32-bit code at 0x000000
|
|
.quad 0x00c0920000007fff # 128MB 32-bit code at 0x000000
|
|
gdt_end:
|
|
|
|
.word 0 # for alignment
|
|
gdt_descr:
|
|
.word gdt_end - gdt - 1 # gdt limit
|
|
.long gdt - setup # gdt base - relocated at run time
|
|
|
|
.word 0 # for alignment
|
|
idt_descr:
|
|
.word 0 # idt limit=0
|
|
.long 0 # idt base=0
|
|
|
|
mt86plus_version:
|
|
.ascii "Memtest86+ v" , MT_VERSION
|
|
.byte 0
|
|
|
|
# Pad to the declared size.
|
|
|
|
.org (SETUP_SECS*512)
|