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CloverBootloader/MemoryFix/OsxAptioFixDrv/X64/AsmFuncsX64.nasm
Sergey Isakov f35acfa5ab restructure sources, preliminary include AptioMemoryFix from OC 
Signed-off-by: Sergey Isakov <isakov-sl@bk.ru>
2019-10-04 16:19:40 +03:00

667 lines
19 KiB
NASM
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;------------------------------------------------------------------------------
;
; Some assembler helper functions plus boot.efi kernel jump callback
;
; by dmazar
;
; converted to nasm by Slice, finished by dmazar
;------------------------------------------------------------------------------
struc XDTR
Limit resw 1
Base resq 1
endstruc
; C callback method called on jump to kernel after boot.efi finishes
extern ASM_PFX(KernelEntryPatchJumpBack)
; saved 64bit state
global ASM_PFX(SavedGDTR)
global ASM_PFX(SavedIDTR)
global ASM_PFX(SavedCR3)
; addresses of relocated MyAsmCopyAndJumpToKernel code - filled by PrepareJumpFromKernel()
global ASM_PFX(MyAsmCopyAndJumpToKernel32Addr)
global ASM_PFX(MyAsmCopyAndJumpToKernel64Addr)
; kernel entry address - filled by KernelEntryPatchJump()
global ASM_PFX(AsmKernelEntry)
; params for kernel image relocation - filled by KernelEntryPatchJumpBack()
global ASM_PFX(AsmKernelImageStartReloc)
global ASM_PFX(AsmKernelImageStart)
global ASM_PFX(AsmKernelImageSize)
; end of MyAsmEntryPatchCode func
global ASM_PFX(MyAsmEntryPatchCodeEnd)
; start and end of MyAsmCopyAndJumpToKernel
global ASM_PFX(MyAsmCopyAndJumpToKernel)
global ASM_PFX(MyAsmCopyAndJumpToKernel32)
global ASM_PFX(MyAsmCopyAndJumpToKernel64)
global ASM_PFX(MyAsmCopyAndJumpToKernelEnd)
;SECTION .data
SECTION .text
;
; Adding data to code segment to avoid some error:
; Undefined symbols for architecture x86_64:
; "_SavedGDTR", referenced from:
; _MyAsmPrepareJumpFromKernel in OsxAptioFixDrv.lib(AsmFuncsX64.obj)
;
; variables accessed from both 32 and 64 bit code
; need to have this exactly in this order
DataBase:
; 64 bit state
SavedGDTROff EQU $-DataBase
ASM_PFX(SavedGDTR):
dw 0
dq 0
SavedIDTROff EQU $-DataBase
ASM_PFX(SavedIDTR):
dw 0
dq 0
align 08h, db 0
SavedCR3Off EQU $-DataBase
ASM_PFX(SavedCR3): DQ 0
SavedCSOff EQU $-DataBase
SavedCS: DW 0
SavedDSOff EQU $-DataBase
SavedDS: DW 0
; 32 bit state
SavedGDTR32Off EQU $-DataBase
SavedGDTR32:
dw 0
dq 0
SavedIDTR32Off EQU $-DataBase
SavedIDTR32:
dw 0
dq 0
SavedCS32Off EQU $-DataBase
SavedCS32: DW 0
SavedDS32Off EQU $-DataBase
SavedDS32: DW 0
SavedESP32Off EQU $-DataBase
SavedESP32: DD 0
align 08h, db 0
; address of relocated MyAsmCopyAndJumpToKernel32 - 64 bit
MyAsmCopyAndJumpToKernel32AddrOff EQU $-DataBase
ASM_PFX(MyAsmCopyAndJumpToKernel32Addr): DQ 0
; address of relocated MyAsmCopyAndJumpToKernel64 - 64 bit
MyAsmCopyAndJumpToKernel64AddrOff EQU $-DataBase
ASM_PFX(MyAsmCopyAndJumpToKernel64Addr): DQ 0
; kernel entry - 64 bit
AsmKernelEntryOff EQU $-DataBase
ASM_PFX(AsmKernelEntry): DQ 0
;
; for copying kernel image from reloc block to proper mem place
;
; kernel image start in reloc block (source) - 64 bit
AsmKernelImageStartRelocOff EQU $-DataBase
ASM_PFX(AsmKernelImageStartReloc): DQ 0
; kernel image start (destination) - 64 bit
AsmKernelImageStartOff EQU $-DataBase
ASM_PFX(AsmKernelImageStart): DQ 0
; kernel image size - 64 bit
AsmKernelImageSizeOff EQU $-DataBase
ASM_PFX(AsmKernelImageSize): DQ 0
align 08h, db 0
; GDT not used since we are reusing UEFI state
; but left here in case will be needed.
;
; GDR record
GDTROff EQU $-DataBase
GDTR dw GDT_END - GDT_BASE - 1 ; GDT limit
GDTR_BASE dq 0 ; GDT base - needs to be set in code
align 08h, db 0
; GDT
GDT_BASE:
; null descriptor
NULL_SEL equ $-GDT_BASE ; 0x00
dw 0 ; limit 15:0
dw 0 ; base 15:0
db 0 ; base 23:16
db 0 ; type
db 0 ; limit 19:16, flags
db 0 ; base 31:24
; 64 bit code segment descriptor
CODE64_SEL equ $-GDT_BASE ; 0x08
dw 0FFFFh ; limit 0xFFFFF
dw 0 ; base 0
db 0
db 09Ah ; P=1 | DPL=00 | S=1 (User) # Type=A=1010: Code/Data=1 | C:Conforming=0 | R:Readable=1 | A:Accessed=0
db 0AFh ; Flags=A=1010: G:Granularity=1 (4K) | D:Default Operand Size=0 (in long mode) | L:Long=1 (64 bit) | AVL=0
db 0
; 32 bit and 64 bit data segment descriptor (in 64 bit almost all is ignored, so can be reused)
DATA_SEL equ $-GDT_BASE ; 0x10
dw 0FFFFh ; limit 0xFFFFF
dw 0 ; base 0
db 0
db 092h ; P=1 | DPL=00 | S=1 (User) # Type=2=0010: Code/Data=0 | E:Expand-Down=0 | W:Writable=1 | A:Accessed=0
db 0CFh ; Flags=C=1100: G:Granularity=1 (4K) | D/B=1 D not used when E=0, for stack B=1 means 32 bit stack | L:Long=0 not used | AVL=0
db 0
; 32 bit code segment descriptor
CODE32_SEL equ $-GDT_BASE ; 0x18
dw 0FFFFh ; limit 0xFFFFF
dw 0 ; base 0
db 0
db 09Ah ; P=1 | DPL=00 | S=1 (User) # Type=A=1010: Code/Data=1 | C:Conforming=0 | R:Readable=1 | A:Accessed=0
db 0CFh ; Flags=C=1100: G:Granularity=1 (4K) | D:Default Operand Size=0 (in long mode) | L:Long=0 (32 bit) | AVL=0
db 0
GDT_END:
;SECTION .text
BITS 64
;------------------------------------------------------------------------------
; UINT64
; EFIAPI
; MyAsmReadSp (
; VOID
; );
;------------------------------------------------------------------------------
GLOBAL ASM_PFX(MyAsmReadSp)
ASM_PFX(MyAsmReadSp):
mov rax, rsp
add rax, 8 ; return SP as caller see it
ret
;------------------------------------------------------------------------------
; VOID
; EFIAPI
; MyAsmPrepareJumpFromKernel (
; );
;------------------------------------------------------------------------------
GLOBAL ASM_PFX(MyAsmPrepareJumpFromKernel)
ASM_PFX(MyAsmPrepareJumpFromKernel):
; save 64 bit state
sgdt [REL ASM_PFX(SavedGDTR)]
sidt [REL ASM_PFX(SavedIDTR)]
mov rax, cr3
mov [REL ASM_PFX(SavedCR3)], rax
mov word [REL SavedCS], cs
mov word [REL SavedDS], ds
; pass DataBase to 32 bit code
lea rax, [REL DataBase]
mov dword [REL DataBaseAdr], eax;
; prepare MyAsmEntryPatchCode:
; patch MyAsmEntryPatchCode with address of MyAsmJumpFromKernel
lea rax, [REL ASM_PFX(MyAsmJumpFromKernel)]
mov dword [REL MyAsmEntryPatchCodeJumpFromKernelPlaceholder], eax
ret
;------------------------------------------------------------------------------
; Code that is used for patching kernel entry to jump back
; to our code (to MyAsmJumpFromKernel):
; - load ecx (rcx) with address to MyAsmJumpFromKernel
; - jump to MyAsmJumpFromKernel
; The same generated opcode must run properly in both 32 and 64 bit.
; 64 bit:
; - we must set rcx to 0 (upper 4 bytes) before loading ecx with address (lower 4 bytes of rcx)
; - this requires xor %rcx, %rcx
; - and that opcode contains 0x48 in front of 32 bit xor %ecx, %ecx
; 32 bit:
; - 0x48 opcode is dec %eax in 32 bit
; - and then we must inc %eax later if 32 bit is detected in MyAsmJumpFromKernel
;
; This code is patched with address of MyAsmJumpFromKernel
; (into MyAsmEntryPatchCodeJumpFromKernelPlaceholder)
; and then copied to kernel entry address by KernelEntryPatchJump()
;------------------------------------------------------------------------------
GLOBAL ASM_PFX(MyAsmEntryPatchCode)
ASM_PFX(MyAsmEntryPatchCode):
BITS 32
dec eax ; -> 48
xor ecx, ecx ; -> 31 C9
db 0b9h ; movl $0x11223344, %ecx -> B9 44 33 22 11
MyAsmEntryPatchCodeJumpFromKernelPlaceholder dd 011223344h
call ecx ; -> FF D1
; jmp ecx ; -> FF E1
;BITS 64
; xor rcx, rcx ; -> 48 31 C9
; mov dword ecx, 011223344h ; -> B9 44 33 22 11
; call rcx ; -> FF D1
; jmp rcx ; -> FF E1
ASM_PFX(MyAsmEntryPatchCodeEnd):
;------------------------------------------------------------------------------
; MyAsmJumpFromKernel
;
; Callback from boot.efi - this is where we jump when boot.efi jumps to kernel.
;
; - test if we are in 32 bit or in 64 bit
; - if 64 bit, then jump to MyAsmJumpFromKernel64
; - else just continue with MyAsmJumpFromKernel32
;------------------------------------------------------------------------------
GLOBAL ASM_PFX(MyAsmJumpFromKernel)
ASM_PFX(MyAsmJumpFromKernel):
; writing in 32 bit, but code must run in 64 bit also
BITS 32
push eax ; save bootArgs pointer to stack
mov dword ecx, 0c0000080h ; EFER MSR number.
rdmsr ; Read EFER.
bt eax, 8 ; Check if LME==1 -> CF=1.
pop eax
jc MyAsmJumpFromKernel64 ; LME==1 -> jump to 64 bit code
; otherwise, continue with MyAsmJumpFromKernel32
; but first add 1 to it since it was decremented in 32 bit
; in MyAsmEntryPatchCode
inc eax
; test the above code in 64 bit - above 32 bit code gives opcode
; that is equivalent to following in 64 bit
;BITS 64
; push rax ; save bootArgs pointer to stack
; movl ecx, 0c0000080h ; EFER MSR number.
; rdmsr ; Read EFER.
; bt eax, 8 ; Check if LME==1 -> CF=1.
; pop rax
; jnc MyAsmJumpFromKernel64 ; LME==1 -> jump to 64 bit code
;------------------------------------------------------------------------------
; MyAsmJumpFromKernel32
;
; Callback from boot.efi in 32 bit mode.
; State is prepared for kernel: 32 bit, no paging, pointer to bootArgs in eax.
;
; MS 64 bit compiler generates only 64 bit opcode, but this function needs
; combined 32 and 64 bit code. Code can be written only with 64 bit instructions,
; but generated opcode must be valid 32 bit. This is a big issue.
; Well, I guess I know now how the guys in Intel are feeling when
; they have to work with MS tools on a similar code.
;
; Another problem is that it's not possible to access saved variables
; from 32 bit code (64 bit code has relative addresses, but 32 bit does not
; and depends on fixes during load and that is not happening sice
; generated code is marked 64 bit, or something similar).
; To overcome this, starting address of ou DataBase is passed in runtime - stored
; to DataBaseAdr below as an argument to mov.
;------------------------------------------------------------------------------
MyAsmJumpFromKernel32:
BITS 32
;hlt ; uncomment to stop here for test
; save bootArgs pointer to edi
mov edi, eax
; load ebx with DataBase - we'll access our saved data with it
db 0BBh ; mov ebx, OFFSET DataBase
DataBaseAdr dd 0
; let's find out kernel entry point - we'll need it to jump back.
; we are called with
; dec eax
; xor ecx, ecx
; mov ecx, 011223344h
; call ecx
; and that left return addr on stack. those instructions
; are 10 bytes long, and if we take address from stack and
; substitute 10 from it, we will get kernel entry point.
pop ecx ; 32 bit: pop ecx
sub ecx, 10
; and save it
mov dword [ebx + AsmKernelEntryOff], ecx
; lets save 32 bit state to be able to recover it later
sgdt [ebx + SavedGDTR32Off]
sidt [ebx + SavedIDTR32Off]
mov word [ebx + SavedCS32Off], cs
mov word [ebx + SavedDS32Off], ds
mov dword [ebx + SavedESP32Off], esp
;
; move to 64 bit mode ...
;
; FIXME: all this with interrupts enabled? no-no
; load saved UEFI GDT, IDT
; will become active after code segment is changed in long jump
; rbx is ebx in 32 bit
lgdt [ebx + SavedGDTROff]
lidt [ebx + SavedIDTROff]
; enable the 64-bit page-translation-table entries by setting CR4.PAE=1
mov eax, cr4
bts eax, 5
mov cr4, eax
; set the long-mode page tables - reuse saved UEFI tables
mov eax, dword [ebx +SavedCR3Off]
mov cr3, eax
; enable long mode (set EFER.LME=1).
mov ecx, 0c0000080h ; EFER MSR number.
rdmsr ; Read EFER.
bts eax, 8 ; Set LME=1.
wrmsr ; Write EFER.
; enable paging to activate long mode (set CR0.PG=1)
mov eax, cr0 ; Read CR0.
bts eax, 31 ; Set PG=1.
mov cr0, eax ; Write CR0.
; jump to the 64-bit code segment
mov ax, word [ebx + SavedCSOff]
push eax
call _RETF32
;
; aloha!
; if there is any luck, we are in 64 bit mode now
;
;hlt ; uncomment to stop here for test
BITS 64
; set segmens
mov ax, word [rbx + SavedDSOff]
mov ds, ax
; set up stack ...
; not sure if needed, but lets set ss to ds
mov ss, ax ; disables interrupts for 1 instruction to load rsp
; lets align the stack
; mov rax, rsp
; and rax, 0fffffffffffffff0h
; mov rsp, rax
and rsp, 0fffffffffffffff0h
; call our C code
; (calling conv.: always reserve place for 4 args on stack)
; KernelEntryPatchJumpBack (rcx = rax = bootArgs, rdx = 0 = 32 bit kernel jump)
mov rcx, rdi
xor rdx, rdx
push rdx
push rdx
push rdx
push rcx
; TEST 64 bit jump
; mov rax, rdi
; mov rdx, qword [AsmKernelEntry]
; jmp rdx
; TEST end
; KernelEntryPatchJumpBack should be EFIAPI
; and rbx should not be changed by EFIAPI calling convention
call ASM_PFX(KernelEntryPatchJumpBack)
;hlt ; uncomment to stop here for test
; return value in rax is bootArgs pointer
mov rdi, rax
;
; time to go back to 32 bit
;
; FIXME: all this with interrupts enabled? no-no
; load saved 32 bit gdtr
lgdt [rbx + SavedGDTR32Off]
; push saved cs and rip (with call) to stack and do retf
mov ax, WORD [rbx + SavedCS32Off]
push rax
call _RETF64
;
; ok, 32 bit opcode again from here
;
BITS 32
; disable paging (set CR0.PG=0)
mov eax, cr0 ; Read CR0.
btr eax, 31 ; Set PG=0.
mov cr0, eax ; Write CR0.
; disable long mode (set EFER.LME=0).
mov ecx, 0c0000080h ; EFER MSR number.
rdmsr ; Read EFER.
btr eax, 8 ; Set LME=0.
wrmsr ; Write EFER.
jmp toNext
toNext:
;
; we are in 32 bit protected mode, no paging
;
; now reload saved 32 bit state data
lidt [ebx + SavedIDTR32Off]
mov ax, word [ebx + SavedDS32Off]
mov ds, ax
mov es, ax
mov fs, ax
mov gs, ax
mov ss, ax ; disables interrupts for 1 instruction to load esp
mov esp, dword [ebx + SavedESP32Off]
;
; prepare vars for copying kernel to proper mem
; and jump to kernel: set registers as needed
; by MyAsmCopyAndJumpToKernel32
;
; boot args back from edi
mov eax, edi
; kernel entry point
mov edx, dword [ebx + AsmKernelEntryOff]
; source, destination and size for kernel copy
mov esi, dword [ebx + AsmKernelImageStartRelocOff]
mov edi, dword [ebx + AsmKernelImageStartOff]
mov ecx, dword [ebx + AsmKernelImageSizeOff]
; address of relocated MyAsmCopyAndJumpToKernel32
mov ebx, dword [ebx + MyAsmCopyAndJumpToKernel32AddrOff]
; note: ebx not valid as a pointer to DataBase any more
;
; jump to MyAsmCopyAndJumpToKernel32
;
jmp ebx
_RETF64:
DB 048h
_RETF32:
retf
;------------------------------------------------------------------------------
; MyAsmJumpFromKernel64
;
; Callback from boot.efi in 64 bit mode.
; State is prepared for kernel: 64 bit, pointer to bootArgs in rax.
;------------------------------------------------------------------------------
MyAsmJumpFromKernel64:
BITS 64
; let's find out kernel entry point - we'll need it to jump back.
pop rcx
sub rcx, 10
; and save it
mov qword [REL ASM_PFX(AsmKernelEntry)], rcx
; call our C code
; (calling conv.: always reserve place for 4 args on stack)
; KernelEntryPatchJumpBack (rcx = rax = bootArgs, rdx = 1 = 64 bit kernel jump)
mov rcx, rax
xor rdx, rdx
inc edx
push rdx
push rdx
push rdx
push rcx
; KernelEntryPatchJumpBack should be EFIAPI
call ASM_PFX(KernelEntryPatchJumpBack)
;hlt ; uncomment to stop here for test
; return value in rax is bootArgs pointer
;
; prepare vars for copying kernel to proper mem
; and jump to kernel: set registers as needed
; by MyAsmCopyAndJumpToKernel64
;
; kernel entry point
mov rdx, [REL ASM_PFX(AsmKernelEntry)]
; source, destination and size for kernel copy
mov rsi, [REL ASM_PFX(AsmKernelImageStartReloc)]
mov rdi, [REL ASM_PFX(AsmKernelImageStart)]
mov rcx, [REL ASM_PFX(AsmKernelImageSize)]
; address of relocated MyAsmCopyAndJumpToKernel64
mov rbx, [REL ASM_PFX(MyAsmCopyAndJumpToKernel64Addr)]
;
; jump to MyAsmCopyAndJumpToKernel64
;
jmp rbx
ret
;MyAsmJumpFromKernel64 ENDP
;------------------------------------------------------------------------------
; MyAsmCopyAndJumpToKernel
;
; This is the last part of the code - it will copy kernel image from reloc
; block to proper mem place and jump to kernel.
; There are separate versions for 32 and 64 bit.
; This code will be relocated (copied) to higher mem by PrepareJumpFromKernel().
;------------------------------------------------------------------------------
align 08h
GLOBAL ASM_PFX(MyAsmCopyAndJumpToKernel)
ASM_PFX(MyAsmCopyAndJumpToKernel):
;------------------------------------------------------------------------------
; MyAsmCopyAndJumpToKernel32
;
; Expects:
; EAX = address of boot args (proper address, not from reloc block)
; EDX = kernel entry point
; ESI = start of kernel image in reloc block (source)
; EDI = proper start of kernel image (destination)
; ECX = kernel image size in bytes
;------------------------------------------------------------------------------
GLOBAL ASM_PFX(MyAsmCopyAndJumpToKernel32)
ASM_PFX(MyAsmCopyAndJumpToKernel32):
BITS 32
;
; we will move double words (4 bytes)
; so ajust ECX to number of double words.
; just in case ECX is not multiple of 4 - inc by 1
;
shr ecx, 2
inc ecx
;
; copy kernel image from reloc block to proper mem place.
; all params should be already set:
; ECX = number of double words
; DS:ESI = source
; ES:EDI = destination
;
cld ; direction is up
rep movsd
;
; and finally jump to kernel:
; EAX already contains bootArgs pointer,
; and EDX contains kernel entry point
;
;hlt
jmp edx
;MyAsmCopyAndJumpToKernel32 ENDP
MyAsmCopyAndJumpToKernel32End:
;------------------------------------------------------------------------------
; MyAsmCopyAndJumpToKernel64
;
; Expects:
; RAX = address of boot args (proper address, not from reloc block)
; RDX = kernel entry point
; RSI = start of kernel image in reloc block (source)
; RDI = proper start of kernel image (destination)
; RCX = kernel image size in bytes
;------------------------------------------------------------------------------
align 08h
GLOBAL ASM_PFX(MyAsmCopyAndJumpToKernel64)
ASM_PFX(MyAsmCopyAndJumpToKernel64):
BITS 64
;
; we will move quad words (8 bytes)
; so ajust RCX to number of double words.
; just in case RCX is not multiple of 8 - inc by 1
;
shr rcx, 3
inc rcx
;
; copy kernel image from reloc block to proper mem place.
; all params should be already set:
; RCX = number of double words
; RSI = source
; RDI = destination
;
cld ; direction is up
rep movsq
;
; and finally jump to kernel:
; RAX already contains bootArgs pointer,
; and RDX contains kernel entry point
;
; hlt
jmp rdx
;MyAsmCopyAndJumpToKernel64 ENDP
MyAsmCopyAndJumpToKernel64End:
GLOBAL ASM_PFX(MyAsmCopyAndJumpToKernelEnd)
ASM_PFX(MyAsmCopyAndJumpToKernelEnd):
;END
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