andrius
/
stage0-uefi
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

hex0.S: Use push rax to allocate stack space instead of sub rsp, 32. 

Easier to encode to hex0 and also more efficient for smaller allocations
such as sub rsp, 16.
This commit is contained in:
Andrius Štikonas 2022-07-17 12:49:03 +01:00
parent 1d3ea9e5c0
commit e7bd0b67ab
1 changed files with 27 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
amd64/Development/hex0.S
View File

@ -37,7 +37,10 @@ _start:
push 0 # arg5 = NULL
mov r9, rcx # arg4 = image_handle
# arg1 = ImageHandle (already set)
sub rsp, 32 # allocate stack
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
push rax # allocate shadow stack space for UEFI function
call r14 # system->boot->open_protocol(image_handle, &guid, &image, image_handle, 0, EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL);
mov rax, [rsp+64] # get image
@ -76,14 +79,18 @@ loop_options2: # Skip argv[1]
push 0 # arg5 = NULL
mov r9, r15 # arg4 = image_handle
mov rcx, [rcx+24] # arg1 = root_device = image->device
sub rsp, 32 # allocate stack
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
push rax # allocate shadow stack space for UEFI function
call r14 # system->boot->open_protocol(root_device, &guid, &rootfs, image_handle, 0, EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL);
mov rcx, [rsp+64] # get rootfs
# Get rootfs
push rdx # allocate stack for rootdir
mov rdx, rsp # arg2 = &rootdir
sub rsp, 16 # allocate stack
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)
mov r14, [rsp+16] # save &rootdir
@ -94,7 +101,10 @@ loop_options2: # Skip argv[1]
mov r9, 0x8000000000000003 # arg4 = EFI_FILE_MODE_CREATE| EFI_FILE_MODE_WRITE | EFI_FILE_MODE_READ
mov r8, r13 # arg3 = out
mov rcx, r14 # arg1 = rootdir
sub rsp, 32 # allocate stack
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
push rax # allocate shadow stack space for UEFI function
call [rcx+8] # rootdir->open()
mov r13, [rsp+40] # get fout
@ -105,7 +115,10 @@ loop_options2: # Skip argv[1]
mov r9, 1 # arg4 = EFI_FILE_MODE_READ
mov r8, r12 # arg3 = in
mov rcx, r14 # arg1 = rootdir
sub rsp, 32 # allocate stack
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
push rax # allocate shadow stack space for UEFI function
call [rcx+8] # rootdir->open()
mov r12, [rsp+40] # get fin
@ -232,9 +245,13 @@ read_byte:
mov rdx, rsp # arg2 = &size
push rbx # allocate stack
mov r8, rsp # arg3 = &input
sub rsp, 24 # allocate stack
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()
add rsp, 24 # deallocate stack
pop rax # deallocate stack
pop rax # deallocate stack
pop rax # deallocate stack
pop rax # save input to rax
pop rbx # save size to rbx
@ -251,7 +268,9 @@ write_byte:
mov rdx, rsp # arg2 = &size
push rax # allocate stack
mov r8, rsp # arg3 = &output
sub rsp, 24 # allocate stack
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