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/** @file
Specific relocation fixups for ARM architecture.
Copyright (c) 2006 - 2009, Intel Corporation. All rights reserved.<BR>
Portions copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php.
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#include "BasePeCoffLibInternals.h"
#include <Library/BaseLib.h>
/**
Pass in a pointer to an ARM MOVT or MOVW immediate instruciton and
return the immediate data encoded in the instruction.
@param Instruction Pointer to ARM MOVT or MOVW immediate instruction
@return Immediate address encoded in the instruction
**/
UINT16
ThumbMovtImmediateAddress (
IN UINT16 *Instruction
)
{
UINT32 Movt;
UINT16 Address;
// Thumb2 is two 16-bit instructions working together. Not a single 32-bit instruction
// Example MOVT R0, #0 is 0x0000f2c0 or 0xf2c0 0x0000
Movt = (*Instruction << 16) | (*(Instruction + 1));
// imm16 = imm4:i:imm3:imm8
// imm4 -> Bit19:Bit16
// i -> Bit26
// imm3 -> Bit14:Bit12
// imm8 -> Bit7:Bit0
Address = (UINT16)(Movt & 0x000000ff); // imm8
Address |= (UINT16)((Movt >> 4) & 0x0000f700); // imm4 imm3
Address |= (((Movt & BIT26) != 0) ? BIT11 : 0); // i
return Address;
}
/**
Update an ARM MOVT or MOVW immediate instruction immediate data.
@param Instruction Pointer to ARM MOVT or MOVW immediate instruction
@param Address New addres to patch into the instruction
**/
VOID
ThumbMovtImmediatePatch (
IN OUT UINT16 *Instruction,
IN UINT16 Address
)
{
UINT16 Patch;
// First 16-bit chunk of instruciton
Patch = ((Address >> 12) & 0x000f); // imm4
Patch |= (((Address & BIT11) != 0) ? BIT10 : 0); // i
// Mask out instruction bits and or in address
*(Instruction) = (*Instruction & ~0x040f) | Patch;
// Second 16-bit chunk of instruction
Patch = Address & 0x000000ff; // imm8
Patch |= ((Address << 4) & 0x00007000); // imm3
// Mask out instruction bits and or in address
Instruction++;
*Instruction = (*Instruction & ~0x70ff) | Patch;
}
/**
Pass in a pointer to an ARM MOVW/MOVT instruciton pair and
return the immediate data encoded in the two` instruction.
@param Instructions Pointer to ARM MOVW/MOVT insturction pair
@return Immediate address encoded in the instructions
**/
UINT32
ThumbMovwMovtImmediateAddress (
IN UINT16 *Instructions
)
{
UINT16 *Word;
UINT16 *Top;
Word = Instructions; // MOVW
Top = Word + 2; // MOVT
return (ThumbMovtImmediateAddress (Top) << 16) + ThumbMovtImmediateAddress (Word);
}
/**
Update an ARM MOVW/MOVT immediate instruction instruction pair.
@param Instructions Pointer to ARM MOVW/MOVT instruction pair
@param Address New addres to patch into the instructions
**/
VOID
ThumbMovwMovtImmediatePatch (
IN OUT UINT16 *Instructions,
IN UINT32 Address
)
{
UINT16 *Word;
UINT16 *Top;
Word = Instructions; // MOVW
Top = Word + 2; // MOVT
ThumbMovtImmediatePatch (Word, (UINT16)(Address & 0xffff));
ThumbMovtImmediatePatch (Top, (UINT16)(Address >> 16));
}
/**
Performs an ARM-based specific relocation fixup and is a no-op on other
instruction sets.
@param Reloc The pointer to the relocation record.
@param Fixup The pointer to the address to fix up.
@param FixupData The pointer to a buffer to log the fixups.
@param Adjust The offset to adjust the fixup.
@return Status code.
**/
RETURN_STATUS
PeCoffLoaderRelocateImageEx (
IN UINT16 *Reloc,
IN OUT CHAR8 *Fixup,
IN OUT CHAR8 **FixupData,
IN UINT64 Adjust
)
{
UINT16 *Fixup16;
UINT32 FixupVal;
Fixup16 = (UINT16 *) Fixup;
switch ((*Reloc) >> 12) {
case EFI_IMAGE_REL_BASED_ARM_MOV32T:
FixupVal = ThumbMovwMovtImmediateAddress (Fixup16) + (UINT32)Adjust;
ThumbMovwMovtImmediatePatch (Fixup16, FixupVal);
if (*FixupData != NULL) {
*FixupData = ALIGN_POINTER(*FixupData, sizeof(UINT64));
// Fixup16 is not aligned so we must copy it. Thumb instructions are streams of 16 bytes.
CopyMem (*FixupData, Fixup16, sizeof (UINT64));
*FixupData = *FixupData + sizeof(UINT64);
}
break;
case EFI_IMAGE_REL_BASED_ARM_MOV32A:
ASSERT (FALSE);
// break omitted - ARM instruction encoding not implemented
default:
return RETURN_UNSUPPORTED;
}
return RETURN_SUCCESS;
}
/**
Returns TRUE if the machine type of PE/COFF image is supported. Supported
does not mean the image can be executed it means the PE/COFF loader supports
loading and relocating of the image type. It's up to the caller to support
the entry point.
@param Machine Machine type from the PE Header.
@return TRUE if this PE/COFF loader can load the image
**/
BOOLEAN
PeCoffLoaderImageFormatSupported (
IN UINT16 Machine
)
{
if ((Machine == IMAGE_FILE_MACHINE_ARMTHUMB_MIXED) || (Machine == IMAGE_FILE_MACHINE_EBC)) {
return TRUE;
}
return FALSE;
}
/**
Performs an ARM-based specific re-relocation fixup and is a no-op on other
instruction sets. This is used to re-relocated the image into the EFI virtual
space for runtime calls.
@param Reloc The pointer to the relocation record.
@param Fixup The pointer to the address to fix up.
@param FixupData The pointer to a buffer to log the fixups.
@param Adjust The offset to adjust the fixup.
@return Status code.
**/
RETURN_STATUS
PeHotRelocateImageEx (
IN UINT16 *Reloc,
IN OUT CHAR8 *Fixup,
IN OUT CHAR8 **FixupData,
IN UINT64 Adjust
)
{
UINT16 *Fixup16;
UINT32 FixupVal;
Fixup16 = (UINT16 *)Fixup;
switch ((*Reloc) >> 12) {
case EFI_IMAGE_REL_BASED_ARM_MOV32T:
*FixupData = ALIGN_POINTER (*FixupData, sizeof (UINT64));
if (*(UINT64 *) (*FixupData) == ReadUnaligned64 ((UINT64 *)Fixup16)) {
FixupVal = ThumbMovwMovtImmediateAddress (Fixup16) + (UINT32)Adjust;
ThumbMovwMovtImmediatePatch (Fixup16, FixupVal);
}
break;
case EFI_IMAGE_REL_BASED_ARM_MOV32A:
ASSERT (FALSE);
// break omitted - ARM instruction encoding not implemented
default:
DEBUG ((EFI_D_ERROR, "PeHotRelocateEx:unknown fixed type\n"));
return RETURN_UNSUPPORTED;
}
return RETURN_SUCCESS;
}
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