Jezura777/FlatEFILoader
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Makefile + fixed GetMemMap + updated readme

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Jezura777 2025-04-01 13:03:46 +02:00
parent 925aa01c9b
commit 9c3495c98a
5 changed files with 367 additions and 5 deletions
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8
Makefile Normal file
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@ -0,0 +1,8 @@
bootefi.efi: bootefi.asm uefi.inc
fasm bootefi.asm
run: bootefi.efi
uefi-run bootefi.efi -b /usr/share/ovmf/x64/OVMF.4m.fd
clean: bootefi.efi
rm bootefi.efi

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README Normal file
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FlatEFILoader
=============
FEFIL is a simple EFI bootloader written in flatassembler. It tries to be
understandable by mere mortals
TODO
====
- [X] Make GetMemoryMap and ExitBootServices work
- [ ] Get GOP frame buffer and load it to arbitrary memory space
- [ ] Indicate boot success with frame buffer
- [ ] EDID multiple screens and their resolution

3
README.md
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@ -1,3 +0,0 @@
# FlatEFILoader
FEFIL is a EFI bootloader written in flatassembler

22
bootefi.asm
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@ -60,7 +60,21 @@ main:
mov rdx, BootMsg mov rdx, BootMsg
call print call print
;.GetGOP:
; mov rcx, EFI_GRAPHICS_OUTPUT_UUID
; mov rdx, 3
; mov r8, Video
;
; mov rax, [BootSrvc]
; call_safe [rax + EFI_BOOT_SERVICES_TABLE.LocateProtocol]
;
; cmp rax, EFI_SUCCES
; jne .error
;
; mov rax, [Video]
; mov rbx, [rax + EFI_GRAPHICS_OUTPUT_PROTOCOL_MODE.MaxMode]
; jmp .
; TODO: Get and store framebuffer ; TODO: Get and store framebuffer
; Getting the memory map is kind of harder (not in this case), normally ; Getting the memory map is kind of harder (not in this case), normally
@ -76,6 +90,8 @@ main:
; *MemMapDescSize, ; *MemMapDescSize,
; *MemMapDescVer) ; *MemMapDescVer)
.GetMemMap: .GetMemMap:
mov rax, [BootSrvc]
lea rcx, [MemMapSize] lea rcx, [MemMapSize]
mov rdx, [MemMapBuff] mov rdx, [MemMapBuff]
lea r8, [MemMapKey] lea r8, [MemMapKey]
@ -85,7 +101,7 @@ main:
lea r10, [MemMapDescVer] lea r10, [MemMapDescVer]
mov [rsp+32], r10 mov [rsp+32], r10
call [BootSrvc + EFI_BOOT_SERVICES_TABLE.GetMemoryMap] call [rax + EFI_BOOT_SERVICES_TABLE.GetMemoryMap]
; if it returns buffer too small run the function again as it filled out ; if it returns buffer too small run the function again as it filled out
; the needed buffer length ; the needed buffer length
@ -106,7 +122,8 @@ main:
mov rcx, [ImgHdl] mov rcx, [ImgHdl]
mov rdx, [MemMapKey] mov rdx, [MemMapKey]
call_safe [BootSrvc + EFI_BOOT_SERVICES_TABLE.ExitBootServices] mov rax, [BootSrvc]
call_safe [rax + EFI_BOOT_SERVICES_TABLE.ExitBootServices]
cmp rax, EFI_SUCCESS cmp rax, EFI_SUCCESS
jne .error jne .error
@ -138,6 +155,7 @@ ImgHdl dq ?
SysTbl dq ? SysTbl dq ?
BootSrvc dq ? BootSrvc dq ?
Output dq ? Output dq ?
Video dq ?
MemMapSize dq 32768 MemMapSize dq 32768
MemMapKey dq ? MemMapKey dq ?

326
uefi.inc Normal file
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;*********************************************************************
;* *
;* UEFI library for fasm by bzt, Public Domain *
;* *
;*********************************************************************
; include x86asm.net's efi.inc
;include 'efi.inc'
struc int8 {
. db ?
}
struc int16 {
align 2
. dw ?
}
struc int32 {
align 4
. dd ?
}
struc int64 {
align 8
. dq ?
}
struc intn {
align 8
. dq ?
}
struc dptr {
align 8
. dq ?
}
;symbols
; EFIERR = 0x8000000000000000
EFI_SUCCESS = 0
EFI_LOAD_ERROR = 1 ;or EFIERR
EFI_INVALID_PARAMETER = 2 ;or EFIERR
EFI_UNSUPPORTED = 3;or EFIERR
EFI_BAD_BUFFER_SIZE = 4;or EFIERR
EFI_BUFFER_TOO_SMALL = 5;or EFIERR
EFI_NOT_READY = 6;or EFIERR
EFI_DEVICE_ERROR = 7;or EFIERR
EFI_WRITE_PROTECTED = 8;or EFIERR
EFI_OUT_OF_RESOURCES = 9;or EFIERR
EFI_VOLUME_CORRUPTED = 10;or EFIERR
EFI_VOLUME_FULL = 11;or EFIERR
EFI_NO_MEDIA = 12;or EFIERR
EFI_MEDIA_CHANGED = 13;or EFIERR
EFI_NOT_FOUND = 14;or EFIERR
EFI_ACCESS_DENIED = 15;or EFIERR
EFI_NO_RESPONSE = 16;or EFIERR
EFI_NO_MAPPING = 17;or EFIERR
EFI_TIMEOUT = 18;or EFIERR
EFI_NOT_STARTED = 19;or EFIERR
EFI_ALREADY_STARTED = 20;or EFIERR
EFI_ABORTED = 21;or EFIERR
EFI_ICMP_ERROR = 22;or EFIERR
EFI_TFTP_ERROR = 23;or EFIERR
EFI_PROTOCOL_ERROR = 24;or EFIERR
; ConOut Colors :)
EFI_BLACK = 0x00
EFI_BLUE = 0x01
EFI_GREEN = 0x02
EFI_CYAN = 0x03
EFI_RED = 0x04
EFI_MAGENTA = 0x05
EFI_BROWN = 0x06
EFI_LIGHTGRAY = 0x07
EFI_BRIGHT = 0x08
EFI_DARKGRAY = 0x08
EFI_LIGHTBLUE = 0x09
EFI_LIGHTGREEN = 0x0A
EFI_LIGHTCYAN = 0x0B
EFI_LIGHTRED = 0x0C
EFI_LIGHTMAGENTA = 0x0D
EFI_YELLOW = 0x0E
EFI_WHITE = 0x0F
EFI_BACKGROUND_BLACK = 0x00
EFI_BACKGROUND_BLUE = 0x10
EFI_BACKGROUND_GREEN = 0x20
EFI_BACKGROUND_CYAN = 0x30
EFI_BACKGROUND_RED = 0x40
EFI_BACKGROUND_MAGENTA = 0x50
EFI_BACKGROUND_BROWN = 0x60
EFI_BACKGROUND_LIGHTGRAY = 0x70
;helper macro for definition of relative structure member offsets
macro struct name
{
virtual at 0
name name
end virtual
}
;structures
EFI_SYSTEM_TABLE_SIGNATURE equ 49h,42h,49h,20h,53h,59h,53h,54h
struc EFI_TABLE_HEADER {
.Signature int64
.Revision int32
.HeaderSize int32
.CRC32 int32
.Reserved int32
}
struct EFI_TABLE_HEADER
struc EFI_SYSTEM_TABLE {
.Hdr EFI_TABLE_HEADER
.FirmwareVendor dptr
.FirmwareRevision int32
.ConsoleInHandle dptr
.ConIn dptr
.ConsoleOutHandle dptr
.ConOut dptr
.StandardErrorHandle dptr
.StdErr dptr
.RuntimeServices dptr
.BootServices dptr
.NumberOfTableEntries intn
.ConfigurationTable dptr
}
struct EFI_SYSTEM_TABLE
struc SIMPLE_TEXT_OUTPUT_INTERFACE {
.Reset dptr
.OutputString dptr
.TestString dptr
.QueryMode dptr
.SetMode dptr
.SetAttribute dptr
.ClearScreen dptr
.SetCursorPosition dptr
.EnableCursor dptr
.Mode dptr
}
struct SIMPLE_TEXT_OUTPUT_INTERFACE
;---include ends
struc SIMPLE_INPUT_INTERFACE {
.Reset dptr
.ReadKeyStroke dptr
.WaitForKey dptr
}
struct SIMPLE_INPUT_INTERFACE
struc EFI_BOOT_SERVICES_TABLE {
.Hdr EFI_TABLE_HEADER
.RaisePriority dptr
.RestorePriority dptr
.AllocatePages dptr
.FreePages dptr
.GetMemoryMap dptr
.AllocatePool dptr
.FreePool dptr
.CreateEvent dptr
.SetTimer dptr
.WaitForEvent dptr
.SignalEvent dptr
.CloseEvent dptr
.CheckEvent dptr
.InstallProtocolInterface dptr
.ReInstallProtocolInterface dptr
.UnInstallProtocolInterface dptr
.HandleProtocol dptr
.Void dptr
.RegisterProtocolNotify dptr
.LocateHandle dptr
.LocateDevicePath dptr
.InstallConfigurationTable dptr
.ImageLoad dptr
.ImageStart dptr
.Exit dptr
.ImageUnLoad dptr
.ExitBootServices dptr
.GetNextMonotonicCount dptr
.Stall dptr
.SetWatchdogTimer dptr
.ConnectController dptr
.DisConnectController dptr
.OpenProtocol dptr
.CloseProtocol dptr
.OpenProtocolInformation dptr
.ProtocolsPerHandle dptr
.LocateHandleBuffer dptr
.LocateProtocol dptr
.InstallMultipleProtocolInterfaces dptr
.UnInstallMultipleProtocolInterfaces dptr
.CalculateCrc32 dptr
.CopyMem dptr
.SetMem dptr
}
struct EFI_BOOT_SERVICES_TABLE
struc EFI_RUNTIME_SERVICES_TABLE {
.Hdr EFI_TABLE_HEADER
.GetTime dptr
.SetTime dptr
.GetWakeUpTime dptr
.SetWakeUpTime dptr
.SetVirtualAddressMap dptr
.ConvertPointer dptr
.GetVariable dptr
.GetNextVariableName dptr
.SetVariable dptr
.GetNextHighMonoCount dptr
.ResetSystem dptr
}
struct EFI_RUNTIME_SERVICES_TABLE
struc EFI_TIME {
.Year int16
.Month int8
.Day int8
.Hour int8
.Minute int8
.Second int8
.Pad1 int8
.Nanosecond int32
.TimeZone int16
.Daylight int8
.Pad2 int8
.sizeof rb 1
}
struct EFI_TIME
EFI_LOADED_IMAGE_PROTOCOL_UUID equ 0A1h,31h,1bh,5bh,62h,95h,0d2h,11h,8Eh,3Fh,0h,0A0h,0C9h,69h,72h,3Bh
struc EFI_LOADED_IMAGE_PROTOCOL {
.Revision int32
.ParentHandle int64
.SystemTable dptr
.DeviceHandle int64
.FilePath dptr
.Reserved int64
.LoadOptionsSize int32
.ImageBase dptr
.ImageSize int64
.ImageCodeType int32
.ImageDataType int32
.UnLoad dptr
}
struct EFI_LOADED_IMAGE_PROTOCOL
EFI_BLOCK_IO_PROTOCOL_UUID equ 21h,5bh,4eh,96h,59h,64h,0d2h,11h,8eh,39h,00h,0a0h,0c9h,69h,72h,3bh
struc EFI_BLOCK_IO_PROTOCOL {
.Revision int64
.Media dptr
.Reset dptr
.ReadBlocks dptr
.WriteBlocks dptr
.FlushBlocks dptr
}
struct EFI_BLOCK_IO_PROTOCOL
struc EFI_BLOCK_IO_MEDIA {
.MediaId int32
.RemovableMedia int8
.MediaPresent int8
.LogicalPartition int8
.ReadOnly int8
.WriteCaching int8
.BlockSize int32
.IoAlign int32
.LastBlock int64
}
struct EFI_BLOCK_IO_MEDIA
EFI_GRAPHICS_OUTPUT_PROTOCOL_UUID equ 0deh, 0a9h, 42h,90h,0dch,023h,38h,04ah,96h,0fbh,7ah,0deh,0d0h,80h,51h,6ah
struc EFI_GRAPHICS_OUTPUT_PROTOCOL {
.QueryMode dptr
.SetMode dptr
.Blt dptr
.Mode dptr
}
struct EFI_GRAPHICS_OUTPUT_PROTOCOL
struc EFI_GRAPHICS_OUTPUT_PROTOCOL_MODE {
.MaxMode int32
.CurrentMode int32
.ModeInfo dptr
.SizeOfModeInfo intn
.FrameBufferBase dptr
.FrameBufferSize intn
}
struct EFI_GRAPHICS_OUTPUT_PROTOCOL_MODE
struc EFI_GRAPHICS_OUTPUT_MODE_INFORMATION {
.Version int32
.HorizontalResolution int32
.VerticalResolution int32
.PixelFormat int32
.RedMask int32
.GreenMask int32
.BlueMask int32
.Reserved int32
.PixelsPerScanline int32
}
struct EFI_GRAPHICS_OUTPUT_MODE_INFORMATION
;---macros to make life easier---
;call it early, after entry point is the best
macro InitializeLib
{
clc
or rdx, rdx
jz .badout
cmp dword [rdx], 20494249h
je @f
.badout: xor rcx, rcx
xor rdx, rdx
stc
@@: mov [efi_handler], rcx ; ImageHandle
mov [efi_ptr], rdx ; pointer to SystemTable
}
;*********************************************************************
;* Library functions *
;*********************************************************************
section '.data' data readable writeable
efi_handler: dq 0
efi_ptr: dq 0
uefi_rsptmp: dq 0