2 // Copyright (c) 2011-2013, ARM Limited. All rights reserved.
3 // Copyright (c) 2015-2016, Linaro Limited. All rights reserved.
5 // This program and the accompanying materials
6 // are licensed and made available under the terms and conditions of the BSD License
7 // which accompanies this distribution. The full text of the license may be found at
8 // http://opensource.org/licenses/bsd-license.php
10 // THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
15 #include <AsmMacroIoLib.h>
17 ASM_FUNC(_ModuleEntryPoint)
19 // We are built as a ET_DYN PIE executable, so we need to process all
20 // relative relocations if we are executing from a different offset than we
21 // were linked at. This is only possible if we are running from RAM.
23 ADRL (r4, __reloc_base)
24 ADRL (r5, __reloc_start)
25 ADRL (r6, __reloc_end)
32 // AArch32 uses the ELF32 REL format, which means each entry in the
33 // relocation table consists of
35 // UINT32 offset : the relative offset of the value that needs to
37 // UINT32 info : relocation type and symbol index (the latter is
38 // not used for R_ARM_RELATIVE relocations)
40 ldrd r8, r9, [r5], #8 // read offset into r8 and info into r9
41 cmp r9, #23 // check info == R_ARM_RELATIVE?
42 bne .Lreloc_loop // not a relative relocation? then skip
44 ldr r9, [r8, r4] // read addend into r9
45 add r9, r9, r1 // add image base to addend to get relocated value
46 str r9, [r8, r4] // write relocated value at offset
50 // Do early platform specific actions
51 bl ASM_PFX(ArmPlatformPeiBootAction)
53 // Get ID of this CPU in Multicore system
54 bl ASM_PFX(ArmReadMpidr)
55 // Keep a copy of the MpId register value
58 // Check if we can install the stack at the top of the System Memory or if we need
59 // to install the stacks at the bottom of the Firmware Device (case the FD is located
60 // at the top of the DRAM)
62 // Compute Top of System Memory
63 LDRL (r1, PcdGet64 (PcdSystemMemoryBase))
64 ADRL (r12, PcdGet64 (PcdSystemMemorySize))
67 // calculate the top of memory
72 // truncate the memory used by UEFI to 4 GB range
77 // Calculate Top of the Firmware Device
78 LDRL (r2, PcdGet64 (PcdFdBaseAddress))
79 MOV32 (r3, FixedPcdGet32 (PcdFdSize) - 1)
80 add r3, r3, r2 // r3 = FdTop = PcdFdBaseAddress + PcdFdSize
82 // UEFI Memory Size (stacks are allocated in this region)
83 MOV32 (r4, FixedPcdGet32(PcdSystemMemoryUefiRegionSize))
86 // Reserve the memory for the UEFI region (contain stacks on its top)
89 // Calculate how much space there is between the top of the Firmware and the Top of the System Memory
90 subs r0, r1, r3 // r0 = SystemMemoryTop - FdTop
91 bmi _SetupStack // Jump if negative (FdTop > SystemMemoryTop). Case when the PrePi is in XIP memory outside of the DRAM
95 // Case the top of stacks is the FdBaseAddress
99 // r1 contains the top of the stack (and the UEFI Memory)
101 // Because the 'push' instruction is equivalent to 'stmdb' (decrement before), we need to increment
102 // one to the top of the stack. We check if incrementing one does not overflow (case of DRAM at the
103 // top of the memory space)
105 bcs _SetupOverflowStack
112 // Case memory at the top of the address space. Ensure the top of the stack is EFI_PAGE_SIZE
114 MOV32 (r11, (~EFI_PAGE_MASK) & 0xffffffff)
118 // Calculate the Base of the UEFI Memory
122 // r1 = The top of the Mpcore Stacks
125 // Stack for the primary core = PrimaryCoreStack
126 MOV32 (r2, FixedPcdGet32(PcdCPUCorePrimaryStackSize))
133 // Jump to PrePiCore C code
135 // r1 = UefiMemoryBase
137 bl ASM_PFX(CEntryPoint)
142 ASM_PFX(ArmPlatformPeiBootAction):
144 // If we are booting from RAM using the Linux kernel boot protocol, r0 will
145 // point to the DTB image in memory. Otherwise, use the default value defined
150 LDRL (r0, PcdGet64 (PcdDeviceTreeInitialBaseAddress))
152 0:mov r11, r14 // preserve LR
153 mov r10, r0 // preserve DTB pointer
154 mov r9, r1 // preserve base of image pointer
157 // The base of the runtime image has been preserved in r1. Check whether
158 // the expected magic number can be found in the header.
160 ldr r8, .LArm32LinuxMagic
167 // OK, so far so good. We have confirmed that we likely have a DTB and are
168 // booting via the ARM Linux boot protocol. Update the base-of-image PCD
169 // to the actual relocated value, and add the shift of PcdFdBaseAddress to
170 // PcdFvBaseAddress as well
172 ADRL (r8, PcdGet64 (PcdFdBaseAddress))
173 ADRL (r7, PcdGet64 (PcdFvBaseAddress))
182 // Discover the memory size and offset from the DTB, and record in the
183 // respective PCDs. This will also return false if a corrupt DTB is
184 // encountered. Since we are calling a C function, use the window at the
185 // beginning of the FD image as a temp stack.
187 ADRL (r1, PcdGet64 (PcdSystemMemoryBase))
188 ADRL (r2, PcdGet64 (PcdSystemMemorySize))
195 // Copy the DTB to the slack space right after the 64 byte arm64/Linux style
196 // image header at the base of this image (defined in the FDF), and record the
197 // pointer in PcdDeviceTreeInitialBaseAddress.
199 ADRL (r8, PcdGet64 (PcdDeviceTreeInitialBaseAddress))
211 .byte 0x18, 0x28, 0x6f, 0x01