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