mirror of
https://github.com/memtest86plus/memtest86plus.git
synced 2026-08-26 13:17:12 -05:00
Martin Whitaker
f98ceb1613
This shouldn't be needed because we don't set the relocatable_kernel flag, but the GRUB linuxefi command pays no attention to that. Currently the linuxefi command also ignores the alignment values, but set them now in case that changes in the future.
391 lines
8.1 KiB
ArmAsm
391 lines
8.1 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"
|
|
|
|
#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 0
|
|
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
|
|
|
|
# Pad to the declared size.
|
|
|
|
.org (SETUP_SECS*512)
|