audk/ArmVirtPkg/PrePi/AArch64/ModuleEntryPoint.S

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//
// Copyright (c) 2011-2013, ARM Limited. All rights reserved.
// Copyright (c) 2015-2016, Linaro Limited. All rights reserved.
//
// 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 <AsmMacroIoLibV8.h>
ASM_GLOBAL ASM_PFX(mSystemMemoryEnd)
ASM_FUNC(_ModuleEntryPoint)
//
// We are built as a ET_DYN PIE executable, so we need to process all
// relative relocations regardless of whether or not we are executing from
// the same offset we were linked at. This is only possible if we are
// running from RAM.
//
adr x8, __reloc_base
adr x9, __reloc_start
adr x10, __reloc_end
.Lreloc_loop:
cmp x9, x10
bhs .Lreloc_done
//
// AArch64 uses the ELF64 RELA format, which means each entry in the
// relocation table consists of
//
// UINT64 offset : the relative offset of the value that needs to
// be relocated
// UINT64 info : relocation type and symbol index (the latter is
// not used for R_AARCH64_RELATIVE relocations)
// UINT64 addend : value to be added to the value being relocated
//
ldp x11, x12, [x9], #24 // read offset into x11 and info into x12
cmp x12, #0x403 // check info == R_AARCH64_RELATIVE?
bne .Lreloc_loop // not a relative relocation? then skip
ldr x12, [x9, #-8] // read addend into x12
add x12, x12, x8 // add reloc base to addend to get relocated value
str x12, [x11, x8] // 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 x20, x0
// 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
ldr x1, PcdGet64 (PcdSystemMemoryBase)
ldr x2, PcdGet64 (PcdSystemMemorySize)
sub x2, x2, #1
add x1, x1, x2 // x1 = SystemMemoryTop = PcdSystemMemoryBase + PcdSystemMemorySize
adr x2, mSystemMemoryEnd
str x1, [x2]
// Calculate Top of the Firmware Device
ldr x2, PcdGet64 (PcdFdBaseAddress)
MOV32 (w3, FixedPcdGet32 (PcdFdSize) - 1)
add x3, x3, x2 // x3 = FdTop = PcdFdBaseAddress + PcdFdSize
// UEFI Memory Size (stacks are allocated in this region)
MOV32 (x4, 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 x0, x1, x3 // x0 = SystemMemoryTop - FdTop
b.mi _SetupStack // Jump if negative (FdTop > SystemMemoryTop). Case when the PrePi is in XIP memory outside of the DRAM
cmp x0, x4
b.ge _SetupStack
// Case the top of stacks is the FdBaseAddress
mov x1, x2
_SetupStack:
// x1 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 x21, x1, #1
b.cs _SetupOverflowStack
_SetupAlignedStack:
mov x1, x21
b _GetBaseUefiMemory
_SetupOverflowStack:
// Case memory at the top of the address space. Ensure the top of the stack is EFI_PAGE_SIZE
// aligned (4KB)
and x1, x1, ~EFI_PAGE_MASK
_GetBaseUefiMemory:
// Calculate the Base of the UEFI Memory
sub x21, x1, x4
_GetStackBase:
// r1 = The top of the Mpcore Stacks
// Stack for the primary core = PrimaryCoreStack
MOV32 (x2, FixedPcdGet32(PcdCPUCorePrimaryStackSize))
sub x22, x1, x2
// Stack for the secondary core = Number of Cores - 1
MOV32 (x1, (FixedPcdGet32(PcdCoreCount) - 1) * FixedPcdGet32(PcdCPUCoreSecondaryStackSize))
sub x22, x22, x1
// x22 = The base of the MpCore Stacks (primary stack & secondary stacks)
mov x0, x22
mov x1, x20
//ArmPlatformStackSet(StackBase, MpId, PrimaryStackSize, SecondaryStackSize)
MOV32 (x2, FixedPcdGet32(PcdCPUCorePrimaryStackSize))
MOV32 (x3, FixedPcdGet32(PcdCPUCoreSecondaryStackSize))
bl ASM_PFX(ArmPlatformStackSet)
// Is it the Primary Core ?
mov x0, x10
bl ASM_PFX(ArmPlatformIsPrimaryCore)
cmp x0, #1
bne _PrepareArguments
_PrepareArguments:
mov x0, x20
mov x1, x21
mov x2, x22
// Jump to PrePiCore C code
// x0 = MpId
// x1 = UefiMemoryBase
// x2 = StacksBase
bl ASM_PFX(CEntryPoint)
_NeverReturn:
b _NeverReturn
ASM_PFX(mSystemMemoryEnd): .8byte 0