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//
// Copyright (c) 2011 - 2020, Arm Limited. All rights reserved.<BR>
//
// SPDX-License-Identifier: BSD-2-Clause-Patent
//
//
#include <AsmMacroLib.h>
ASM_FUNC(_ModuleEntryPoint)
// Do early platform specific actions
bl ASM_PFX(ArmPlatformPeiBootAction)
_SetSVCMode:
// 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)
_SystemMemoryEndInit:
ldr x1, mSystemMemoryEnd
_SetupStackPosition:
// r1 = SystemMemoryTop
// Calculate Top of the Firmware Device
MOV64 (x2, FixedPcdGet64(PcdFdBaseAddress))
MOV32 (x3, FixedPcdGet32(PcdFdSize) - 1)
sub x3, x3, #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 SEC 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 x11, x1, #1
b.cs _SetupOverflowStack
_SetupAlignedStack:
mov x1, x11
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 x0, x1, x4
_GetStackBase:
// r1 = The top of the stack
mov sp, x1
// Stack for the primary core = PrimaryCoreStack
MOV32 (x2, FixedPcdGet32(PcdCPUCorePrimaryStackSize))
sub x1, x1, x2
// Move sec startup address into a data register
// Ensure we're jumping to FV version of the code (not boot remapped alias)
ldr x4, =ASM_PFX(CEntryPoint)
// Set the frame pointer to NULL so any backtraces terminate here
mov x29, xzr
// Jump to SEC C code
// x0 = UefiMemoryBase
// x1 = StacksBase
blr x4
_NeverReturn:
b _NeverReturn
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