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//
// Copyright (c) 2011-2013, ARM Limited. All rights reserved.
// Copyright (c) 2015-2016, Linaro Limited. All rights reserved.
//
// SPDX-License-Identifier: BSD-2-Clause-Patent
//
//
#include <AsmMacroIoLib.h>
ASM_FUNC(_ModuleEntryPoint)
//
// We are built as a ET_DYN PIE executable, so we need to process all
// relative relocations if we are executing from a different offset than we
// were linked at. This is only possible if we are running from RAM.
//
ADRL (r4, __reloc_base)
ADRL (r5, __reloc_start)
ADRL (r6, __reloc_end)
.Lreloc_loop:
cmp r5, r6
bhs .Lreloc_done
//
// AArch32 uses the ELF32 REL format, which means each entry in the
// relocation table consists of
//
// UINT32 offset : the relative offset of the value that needs to
// be relocated
// UINT32 info : relocation type and symbol index (the latter is
// not used for R_ARM_RELATIVE relocations)
//
ldrd r8, r9, [r5], #8 // read offset into r8 and info into r9
cmp r9, #23 // check info == R_ARM_RELATIVE?
bne .Lreloc_loop // not a relative relocation? then skip
ldr r9, [r8, r4] // read addend into r9
add r9, r9, r1 // add image base to addend to get relocated value
str r9, [r8, r4] // write relocated value at offset
b .Lreloc_loop
.Lreloc_done:
// Do early platform specific actions
bl ASM_PFX(ArmPlatformPeiBootAction)
// Get ID of this CPU in Multicore system
bl ASM_PFX(ArmReadMpidr)
// Keep a copy of the MpId register value
mov r10, r0
// Check if we can install the stack at the top of the System Memory or if we need
// to install the stacks at the bottom of the Firmware Device (case the FD is located
// at the top of the DRAM)
_SetupStackPosition:
// Compute Top of System Memory
LDRL (r1, PcdGet64 (PcdSystemMemoryBase))
ADRL (r12, PcdGet64 (PcdSystemMemorySize))
ldrd r2, r3, [r12]
// calculate the top of memory
adds r2, r2, r1
sub r2, r2, #1
addcs r3, r3, #1
// truncate the memory used by UEFI to 4 GB range
teq r3, #0
movne r1, #-1
moveq r1, r2
// Calculate Top of the Firmware Device
LDRL (r2, PcdGet64 (PcdFdBaseAddress))
MOV32 (r3, FixedPcdGet32 (PcdFdSize) - 1)
add r3, r3, r2 // r3 = FdTop = PcdFdBaseAddress + PcdFdSize
// UEFI Memory Size (stacks are allocated in this region)
MOV32 (r4, FixedPcdGet32(PcdSystemMemoryUefiRegionSize))
//
// Reserve the memory for the UEFI region (contain stacks on its top)
//
// Calculate how much space there is between the top of the Firmware and the Top of the System Memory
subs r0, r1, r3 // r0 = SystemMemoryTop - FdTop
bmi _SetupStack // Jump if negative (FdTop > SystemMemoryTop). Case when the PrePi is in XIP memory outside of the DRAM
cmp r0, r4
bge _SetupStack
// Case the top of stacks is the FdBaseAddress
mov r1, r2
_SetupStack:
// r1 contains the top of the stack (and the UEFI Memory)
// Because the 'push' instruction is equivalent to 'stmdb' (decrement before), we need to increment
// one to the top of the stack. We check if incrementing one does not overflow (case of DRAM at the
// top of the memory space)
adds r11, r1, #1
bcs _SetupOverflowStack
_SetupAlignedStack:
mov r1, r11
b _GetBaseUefiMemory
_SetupOverflowStack:
// Case memory at the top of the address space. Ensure the top of the stack is EFI_PAGE_SIZE
// aligned (4KB)
MOV32 (r11, (~EFI_PAGE_MASK) & 0xffffffff)
and r1, r1, r11
_GetBaseUefiMemory:
// Calculate the Base of the UEFI Memory
sub r11, r1, r4
_GetStackBase:
// r1 = The top of the Mpcore Stacks
mov sp, r1
// Stack for the primary core = PrimaryCoreStack
MOV32 (r2, FixedPcdGet32(PcdCPUCorePrimaryStackSize))
sub r9, r1, r2
mov r0, r10
mov r1, r11
mov r2, r9
// Jump to PrePiCore C code
// r0 = MpId
// r1 = UefiMemoryBase
// r2 = StacksBase
bl ASM_PFX(CEntryPoint)
_NeverReturn:
b _NeverReturn
ASM_PFX(ArmPlatformPeiBootAction):
//
// If we are booting from RAM using the Linux kernel boot protocol, r0 will
// point to the DTB image in memory. Otherwise, use the default value defined
// by the platform.
//
teq r0, #0
bne 0f
LDRL (r0, PcdGet64 (PcdDeviceTreeInitialBaseAddress))
0:mov r11, r14 // preserve LR
mov r10, r0 // preserve DTB pointer
mov r9, r1 // preserve base of image pointer
//
// The base of the runtime image has been preserved in r1. Check whether
// the expected magic number can be found in the header.
//
ldr r8, .LArm32LinuxMagic
ldr r7, [r1, #0x24]
cmp r7, r8
bne .Lout
//
//
// OK, so far so good. We have confirmed that we likely have a DTB and are
// booting via the ARM Linux boot protocol. Update the base-of-image PCD
// to the actual relocated value, and add the shift of PcdFdBaseAddress to
// PcdFvBaseAddress as well
//
ADRL (r8, PcdGet64 (PcdFdBaseAddress))
ADRL (r7, PcdGet64 (PcdFvBaseAddress))
ldr r6, [r8]
ldr r5, [r7]
sub r5, r5, r6
add r5, r5, r1
str r1, [r8]
str r5, [r7]
//
// Discover the memory size and offset from the DTB, and record in the
// respective PCDs. This will also return false if a corrupt DTB is
// encountered. Since we are calling a C function, use the window at the
// beginning of the FD image as a temp stack.
//
ADRL (r1, PcdGet64 (PcdSystemMemoryBase))
ADRL (r2, PcdGet64 (PcdSystemMemorySize))
mov sp, r5
bl FindMemnode
teq r0, #0
beq .Lout
//
// Copy the DTB to the slack space right after the 64 byte arm64/Linux style
// image header at the base of this image (defined in the FDF), and record the
// pointer in PcdDeviceTreeInitialBaseAddress.
//
ADRL (r8, PcdGet64 (PcdDeviceTreeInitialBaseAddress))
add r9, r9, #0x40
str r9, [r8]
mov r0, r9
mov r1, r10
bl CopyFdt
.Lout:
bx r11
.LArm32LinuxMagic:
.byte 0x18, 0x28, 0x6f, 0x01
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