411 lines
16 KiB
ArmAsm
411 lines
16 KiB
ArmAsm
# SPDX-FileCopyrightText: 2022 Andrius Štikonas <andrius@stikonas.eu>
|
|
# SPDX-FileCopyrightText: 2017 Jeremiah Orians <jeremiah@pdp10.guru>
|
|
#
|
|
# SPDX-License-Identifier: GPL-3.0-or-later
|
|
|
|
# Some of the functions are deliberately inlined at the slight expense of
|
|
# binary size to avoid tricky jump calculations in hex0 code.
|
|
|
|
.global _start
|
|
.text
|
|
|
|
# efi_main(void *image_handle, struct efi_system_table *system)
|
|
_start:
|
|
mov rbp, rsp # save stack pointer
|
|
mov r15, rcx # save image_handle
|
|
mov r14, [rdx+96] # system->boot
|
|
|
|
# Open Loaded Image protocol
|
|
mov r9, r15 # arg4 = image_handle
|
|
lea rdx, [rip+LOADED_IMAGE_PROTOCOL] # guid = &LOADED_IMAGE_PROTOCOL
|
|
mov rcx, r9 # arg1 = image_handle
|
|
push rax # allocate stack for image
|
|
mov r8, rsp # arg3 = &image
|
|
push 1 # arg6 = EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL
|
|
push 0 # arg5 = NULL
|
|
sub rsp, 32 # allocate shadow stack space for UEFI function
|
|
call [r14+280] # system->boot->open_protocol(image_handle, &guid, &image, image_handle, 0, EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL)
|
|
mov rdi, [rsp+48] # save image
|
|
|
|
# Get root file system
|
|
mov r9, r15 # arg4 = image_handle
|
|
lea rdx, [rip+SIMPLE_FS_PROTOCOL] # guid = &SIMPLE_FS_PROTOCOL
|
|
mov rcx, [rdi+24] # arg1 = root_device = image->device
|
|
mov r13, rcx # save root_device
|
|
push rax # allocate stack for rootfs
|
|
mov r8, rsp # arg3 = &rootfs
|
|
push 1 # arg6 = EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL
|
|
push 0 # arg5 = NULL
|
|
sub rsp, 32 # allocate shadow stack space for UEFI function
|
|
call [r14+280] # system->boot->open_protocol(root_device, &guid, &rootfs, image_handle, 0, EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL)
|
|
mov rcx, [rsp+48] # get rootfs
|
|
|
|
# Get root directory
|
|
push rax # allocate stack for rootdir
|
|
mov rdx, rsp # arg2 = &rootdir
|
|
push rax # allocate shadow stack space for UEFI function
|
|
push rax # allocate shadow stack space for UEFI function
|
|
call [rcx+8] # rootfs->open_volume(rootfs, &rootdir)
|
|
pop rax # deallocate stack
|
|
pop rax # deallocate stack
|
|
pop rsi # get rootdir
|
|
|
|
# Push command line arguments onto stack
|
|
mov rbx, [rdi+56] # options = image->load_options
|
|
mov rdx, rbx # save beginning of load_options
|
|
add rbx, [rdi+48] # go to the end of load_options
|
|
push 0 # Save end of arguments (NULL) onto stack
|
|
loop_options:
|
|
cmp rbx, rdx # Check if we are done
|
|
je loop_options_done # We are done
|
|
sub rbx, 2 # --options
|
|
mov al, [rbx] # *options
|
|
cmp al, 0x20 # if *options != ' '
|
|
jne loop_options # then continue looping
|
|
mov BYTE PTR [rbx], 0 # zero it
|
|
add rbx, 2 # ++options
|
|
push rbx # push another argument onto stack
|
|
jmp loop_options # next argument
|
|
loop_options_done:
|
|
|
|
# Open file for reading
|
|
pop r8 # arg3 = in
|
|
push rdx # allocate stack for fin
|
|
mov rdx, rsp # arg2 = &fin
|
|
push 1 # arg5 = EFI_FILE_READ_ONLY
|
|
push 1 # prepare to set arg4 to EFI_FILE_MODE_READ
|
|
pop r9 # arg4 = EFI_FILE_MODE_READ
|
|
mov rcx, rsi # arg1 = rootdir
|
|
sub rsp, 32 # allocate shadow stack space for UEFI function
|
|
call [rcx+8] # rootdir->open()
|
|
add rsp, 40 # deallocate stack
|
|
pop rdi # get fin
|
|
|
|
# Open file for writing
|
|
pop r8 # arg3 = out
|
|
push rdx # allocate stack for fout
|
|
mov rdx, rsp # arg2 = &fout
|
|
push 0 # arg5 = 0
|
|
push 7 # to get 0x8000000000000003 we set the rightmost 3 bits
|
|
pop r9 # and then do right rotation by 1
|
|
ror r9 # arg4 = EFI_FILE_MODE_CREATE| EFI_FILE_MODE_WRITE | EFI_FILE_MODE_READ
|
|
mov rcx, rsi # arg1 = rootdir
|
|
sub rsp, 32 # allocate shadow stack space for UEFI function
|
|
call [rcx+8] # rootdir->open()
|
|
add rsp, 40 # deallocate stack
|
|
pop rbx # get fout
|
|
|
|
# Save variables that are needed for cleanup
|
|
push r13 # save root_device
|
|
push r14 # save system->boot
|
|
push r15 # save image_handle
|
|
push rsi # save rootdir
|
|
|
|
# Allocate pool for single-character label table
|
|
# pointer to table will be stored at the top of the stack
|
|
push rdx # allocate stack for table
|
|
mov r8, rsp # arg3 = &table
|
|
xor edx, edx # zero rdx
|
|
mov dh, 0x8 # arg2 = 256 * 8 = 2048 = 0x800
|
|
push 2
|
|
pop rcx # arg1 = EFI_LOADER_DATA
|
|
sub rsp, 24 # allocate shadow stack space for UEFI
|
|
call [r14+64] # system->boot->allocate_pool(EFI_LOADER_DATA, 2048, &table)
|
|
add rsp, 24 # deallocate stack
|
|
|
|
mov r15, -1 # Our flag for byte processing
|
|
mov r14, 0 # temp storage for the sum
|
|
mov r13, 0 # Our starting IP
|
|
call First_pass # Process it
|
|
|
|
# rewind input file
|
|
mov rcx, rdi # Using our input file
|
|
xor edx, edx # Offset Zero
|
|
push rax # allocate shadow stack space for UEFI function
|
|
push rax # allocate shadow stack space for UEFI function
|
|
call [rcx+56] # fin->set_position(fin, 0)
|
|
pop rax # deallocate stack
|
|
pop rax # deallocate stack
|
|
|
|
mov r15, -1 # Our flag for byte processing
|
|
mov r14, 0 # temp storage for the sum
|
|
mov r13, 0 # Our starting IP
|
|
call Second_pass # Process it
|
|
|
|
jmp Done
|
|
|
|
|
|
First_pass:
|
|
call Read_byte
|
|
|
|
# Deal with EOF
|
|
cmp rax, -4
|
|
je First_pass_done
|
|
|
|
# Check for :
|
|
cmp rax, 0x3a
|
|
jne First_pass_0
|
|
|
|
# Deal with label
|
|
call StoreLabel
|
|
|
|
First_pass_0:
|
|
# Check for %
|
|
cmp rax, 0x25
|
|
je First_pass_pointer
|
|
|
|
# Deal with everything else
|
|
call hex # Process our char
|
|
|
|
# Deal with EOF
|
|
cmp rax, -4
|
|
je First_pass_done
|
|
|
|
# deal with -1 values
|
|
cmp rax, 0
|
|
jl First_pass
|
|
|
|
# deal with toggle
|
|
cmp r15, 0
|
|
je First_pass_1
|
|
add r13, 1 # Increment IP
|
|
|
|
First_pass_1:
|
|
not r15
|
|
jmp First_pass
|
|
|
|
First_pass_pointer:
|
|
# Deal with Pointer to label
|
|
call Read_byte # Drop the char
|
|
add r13, 4 # Increment IP
|
|
jmp First_pass # Loop again
|
|
|
|
First_pass_done:
|
|
RET
|
|
|
|
hex:
|
|
# deal with EOF
|
|
cmp rax, -4
|
|
je EOF
|
|
# deal with line comments starting with #
|
|
cmp rax, 0x23
|
|
je ascii_comment
|
|
# deal with line comments starting with ;
|
|
cmp rax, 0x3b
|
|
je ascii_comment
|
|
# deal all ascii less than 0
|
|
cmp rax, 0x30
|
|
jl ascii_other
|
|
# deal with 0-9
|
|
cmp rax, 0x3a
|
|
jl ascii_num
|
|
# deal with all ascii less than A
|
|
cmp rax, 0x41
|
|
jl ascii_other
|
|
# deal with A-F
|
|
cmp rax, 0x47
|
|
jl ascii_high
|
|
# deal with all ascii less than a
|
|
cmp rax, 0x61
|
|
jl ascii_other
|
|
# deal with a-f
|
|
cmp rax, 0x67
|
|
jl ascii_low
|
|
# The rest that remains needs to be ignored
|
|
jmp ascii_other
|
|
|
|
Second_pass:
|
|
call Read_byte
|
|
|
|
# Deal with EOF
|
|
cmp rax, -4
|
|
je Second_pass_done
|
|
|
|
# Simply drop the label
|
|
cmp rax, 0x3a
|
|
jne Second_pass_0
|
|
|
|
call Read_byte
|
|
jmp Second_pass
|
|
|
|
Second_pass_0:
|
|
# Deal with pointer
|
|
cmp rax, 0x25
|
|
jne Second_pass_1
|
|
|
|
call StorePointer
|
|
jmp Second_pass
|
|
|
|
Second_pass_1:
|
|
# Deal with everything else
|
|
call hex # Process our char
|
|
|
|
# Deal with EOF
|
|
cmp rax, -4
|
|
je Second_pass_done
|
|
|
|
# deal with -1 values
|
|
cmp rax, 0
|
|
jl Second_pass
|
|
|
|
# deal with toggle
|
|
cmp r15, 0
|
|
je print
|
|
|
|
# process first byte of pair
|
|
mov r14, rax
|
|
mov r15, 0
|
|
jmp Second_pass
|
|
|
|
Second_pass_done:
|
|
EOF:
|
|
ret
|
|
ascii_num:
|
|
sub rax, 0x30
|
|
ret
|
|
ascii_low:
|
|
sub rax, 0x57
|
|
ret
|
|
ascii_high:
|
|
sub rax, 0x37
|
|
ret
|
|
ascii_other:
|
|
mov rax, -1
|
|
ret
|
|
ascii_comment:
|
|
call Read_byte
|
|
cmp rax, 0xd
|
|
je ascii_comment_cr
|
|
cmp rax, 0xa
|
|
jne ascii_comment
|
|
ascii_comment_cr:
|
|
mov rax, -1
|
|
ret
|
|
|
|
# process second byte of pair
|
|
print:
|
|
# update the sum and store in output
|
|
shl r14, 4
|
|
add rax, r14
|
|
|
|
# flip the toggle
|
|
not r15 # r15 = -1
|
|
|
|
mov rdx, 1 # set the size of chars we want
|
|
call print_chars
|
|
|
|
add r13, 1 # Increment IP
|
|
jmp Second_pass
|
|
|
|
|
|
Read_byte:
|
|
mov rcx, rdi # arg1 = fin
|
|
push 1 # size = 1
|
|
mov rdx, rsp # arg2 = &size
|
|
xor esi, esi # zero rsi
|
|
push rsi # allocate stack
|
|
mov r8, rsp # arg3 = &input
|
|
push rax # allocate shadow stack space for UEFI function
|
|
push rax # allocate shadow stack space for UEFI function
|
|
push rax # allocate shadow stack space for UEFI function
|
|
call [rcx+32] # fin->read()
|
|
pop rax # deallocate stack
|
|
pop rax # deallocate stack
|
|
pop rax # deallocate stack
|
|
pop rax # save input to rax
|
|
pop rsi # save size to rsi
|
|
|
|
# If the file ended (0 bytes read) return EOF
|
|
test esi, esi # if size == 0
|
|
jne Read_byte_1
|
|
mov rax, -4 # Put EOF in rax
|
|
|
|
Read_byte_1:
|
|
ret # return
|
|
|
|
# Writes bytes stored in rax
|
|
print_chars:
|
|
mov rcx, rbx # arg1 = fout
|
|
push rdx # set size
|
|
mov rdx, rsp # arg2 = &size
|
|
push rax # allocate stack
|
|
mov r8, rsp # arg3 = &output
|
|
push rax # allocate shadow stack space for UEFI function
|
|
push rax # allocate shadow stack space for UEFI function
|
|
push rax # allocate shadow stack space for UEFI function
|
|
call [rcx+40] # fout->write()
|
|
add rsp, 40 # deallocate stack
|
|
|
|
ret # return
|
|
|
|
Get_table_target:
|
|
call Read_byte # Get single char label
|
|
shl rax, 3 # Each label in table takes 8 bytes to store
|
|
mov rcx, [rsp+24] # Get table
|
|
add rax, rcx # Calculate offset
|
|
ret
|
|
|
|
StoreLabel:
|
|
call Get_table_target
|
|
mov [rax], r13 # Write out pointer to table
|
|
ret
|
|
|
|
StorePointer:
|
|
add r13, 4 # Increment IP
|
|
call Get_table_target # Get address of pointer
|
|
mov rax, [rax] # Get pointer
|
|
sub rax, r13 # target - ip
|
|
mov rdx, 4 # set the size of chars we want
|
|
call print_chars
|
|
ret
|
|
|
|
Done:
|
|
pop rcx # restore table
|
|
pop rsi # restore rootdir
|
|
pop r15 # restore image_handle
|
|
pop r14 # restore system->boot
|
|
pop r13 # restore root_device
|
|
|
|
# Free pool
|
|
# arg1 = table
|
|
push rax # allocate shadow stack space for UEFI function
|
|
call [r14+72] # system->boot->free_pool(table)
|
|
|
|
mov rcx, rdi # arg1 = fin
|
|
call [rcx+16] # fin->close()
|
|
mov rcx, rbx # arg1 = fout
|
|
call [rcx+16] # fout->close()
|
|
mov rcx, rsi # arg1 = rootdir
|
|
call [rcx+16] # rootdir->close()
|
|
|
|
mov r8, r15 # arg3 = image_handle
|
|
lea rdx, [rip+SIMPLE_FS_PROTOCOL] # guid = &SIMPLE_FS_PROTOCOL
|
|
mov rcx, r13 # arg1 = root_device
|
|
xor r9, r9 # arg4 = NULL
|
|
sub rsp, 32 # allocate shadow stack space for UEFI function
|
|
call [r14+288] # system->boot->close_protocol(root_device, &guid, image_handle, 0)
|
|
|
|
mov r8, r15 # arg3 = image_handle
|
|
lea rdx, [rip+LOADED_IMAGE_PROTOCOL] # guid = &LOADED_IMAGE_PROTOCOL
|
|
mov rcx, r8 # arg1 = image_handle
|
|
xor r9, r9 # arg4 = NULL
|
|
call [r14+288] # system->boot->close_protocol(image_handle, &guid, image_handle, 0)
|
|
|
|
abort: # used for debugging only
|
|
mov rsp, rbp # restore stack
|
|
ret # return to UEFI
|
|
|
|
|
|
# Protocol GUIDs
|
|
LOADED_IMAGE_PROTOCOL:
|
|
.long 0x5b1b31a1
|
|
.short 0x9562
|
|
.short 0x11d2
|
|
.byte 0x8e, 0x3f, 0x00, 0xa0, 0xc9, 0x69, 0x72, 0x3b
|
|
|
|
SIMPLE_FS_PROTOCOL:
|
|
.long 0x0964e5b22
|
|
.short 0x6459
|
|
.short 0x11d2
|
|
.byte 0x8e, 0x39, 0x00, 0xa0, 0xc9, 0x69, 0x72, 0x3b
|