2 // Copyright (c) 2011-2013, ARM Limited. All rights reserved.
3 // Copyright (c) 2015-2016, Linaro Limited. All rights reserved.
5 // SPDX-License-Identifier: BSD-2-Clause-Patent
9 #include <AsmMacroIoLib.h>
11 ASM_FUNC(_ModuleEntryPoint)
13 // We are built as a ET_DYN PIE executable, so we need to process all
14 // relative relocations if we are executing from a different offset than we
15 // were linked at. This is only possible if we are running from RAM.
17 ADRL (r4, __reloc_base)
18 ADRL (r5, __reloc_start)
19 ADRL (r6, __reloc_end)
26 // AArch32 uses the ELF32 REL format, which means each entry in the
27 // relocation table consists of
29 // UINT32 offset : the relative offset of the value that needs to
31 // UINT32 info : relocation type and symbol index (the latter is
32 // not used for R_ARM_RELATIVE relocations)
34 ldrd r8, r9, [r5], #8 // read offset into r8 and info into r9
35 cmp r9, #23 // check info == R_ARM_RELATIVE?
36 bne .Lreloc_loop // not a relative relocation? then skip
38 ldr r9, [r8, r4] // read addend into r9
39 add r9, r9, r1 // add image base to addend to get relocated value
40 str r9, [r8, r4] // write relocated value at offset
44 // Do early platform specific actions
45 bl ASM_PFX(ArmPlatformPeiBootAction)
47 // Get ID of this CPU in Multicore system
48 bl ASM_PFX(ArmReadMpidr)
49 // Keep a copy of the MpId register value
52 // Check if we can install the stack at the top of the System Memory or if we need
53 // to install the stacks at the bottom of the Firmware Device (case the FD is located
54 // at the top of the DRAM)
56 // Compute Top of System Memory
57 LDRL (r1, PcdGet64 (PcdSystemMemoryBase))
58 ADRL (r12, PcdGet64 (PcdSystemMemorySize))
61 // calculate the top of memory
66 // truncate the memory used by UEFI to 4 GB range
71 // Calculate Top of the Firmware Device
72 LDRL (r2, PcdGet64 (PcdFdBaseAddress))
73 MOV32 (r3, FixedPcdGet32 (PcdFdSize) - 1)
74 add r3, r3, r2 // r3 = FdTop = PcdFdBaseAddress + PcdFdSize
76 // UEFI Memory Size (stacks are allocated in this region)
77 MOV32 (r4, FixedPcdGet32(PcdSystemMemoryUefiRegionSize))
80 // Reserve the memory for the UEFI region (contain stacks on its top)
83 // Calculate how much space there is between the top of the Firmware and the Top of the System Memory
84 subs r0, r1, r3 // r0 = SystemMemoryTop - FdTop
85 bmi _SetupStack // Jump if negative (FdTop > SystemMemoryTop). Case when the PrePi is in XIP memory outside of the DRAM
89 // Case the top of stacks is the FdBaseAddress
93 // r1 contains the top of the stack (and the UEFI Memory)
95 // Because the 'push' instruction is equivalent to 'stmdb' (decrement before), we need to increment
96 // one to the top of the stack. We check if incrementing one does not overflow (case of DRAM at the
97 // top of the memory space)
99 bcs _SetupOverflowStack
106 // Case memory at the top of the address space. Ensure the top of the stack is EFI_PAGE_SIZE
108 MOV32 (r11, (~EFI_PAGE_MASK) & 0xffffffff)
112 // Calculate the Base of the UEFI Memory
116 // r1 = The top of the Mpcore Stacks
119 // Stack for the primary core = PrimaryCoreStack
120 MOV32 (r2, FixedPcdGet32(PcdCPUCorePrimaryStackSize))
127 // Jump to PrePiCore C code
129 // r1 = UefiMemoryBase
131 bl ASM_PFX(CEntryPoint)
136 ASM_PFX(ArmPlatformPeiBootAction):
138 // If we are booting from RAM using the Linux kernel boot protocol, r0 will
139 // point to the DTB image in memory. Otherwise, use the default value defined
144 LDRL (r0, PcdGet64 (PcdDeviceTreeInitialBaseAddress))
146 0:mov r11, r14 // preserve LR
147 mov r10, r0 // preserve DTB pointer
148 mov r9, r1 // preserve base of image pointer
151 // The base of the runtime image has been preserved in r1. Check whether
152 // the expected magic number can be found in the header.
154 ldr r8, .LArm32LinuxMagic
161 // OK, so far so good. We have confirmed that we likely have a DTB and are
162 // booting via the ARM Linux boot protocol. Update the base-of-image PCD
163 // to the actual relocated value, and add the shift of PcdFdBaseAddress to
164 // PcdFvBaseAddress as well
166 ADRL (r8, PcdGet64 (PcdFdBaseAddress))
167 ADRL (r7, PcdGet64 (PcdFvBaseAddress))
176 // Discover the memory size and offset from the DTB, and record in the
177 // respective PCDs. This will also return false if a corrupt DTB is
178 // encountered. Since we are calling a C function, use the window at the
179 // beginning of the FD image as a temp stack.
181 ADRL (r1, PcdGet64 (PcdSystemMemoryBase))
182 ADRL (r2, PcdGet64 (PcdSystemMemorySize))
189 // Copy the DTB to the slack space right after the 64 byte arm64/Linux style
190 // image header at the base of this image (defined in the FDF), and record the
191 // pointer in PcdDeviceTreeInitialBaseAddress.
193 ADRL (r8, PcdGet64 (PcdDeviceTreeInitialBaseAddress))
205 .byte 0x18, 0x28, 0x6f, 0x01