summaryrefslogtreecommitdiff
path: root/ArmVirtPkg/PrePi/AArch64/ModuleEntryPoint.S
blob: 568d0086d662927c4aa9dcdbea0758744742e8a6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
//
//  Copyright (c) 2011-2013, ARM Limited. All rights reserved.
//  Copyright (c) 2015, 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>
#include <Base.h>
#include <Library/PcdLib.h>
#include <AutoGen.h>

.text
.align 3

GCC_ASM_IMPORT(ArmPlatformIsPrimaryCore)
GCC_ASM_IMPORT(ArmReadMpidr)
GCC_ASM_IMPORT(ArmPlatformPeiBootAction)
GCC_ASM_IMPORT(ArmPlatformStackSet)
GCC_ASM_EXPORT(_ModuleEntryPoint)

StartupAddr:        .8byte ASM_PFX(CEntryPoint)

ASM_PFX(_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   x10, 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

  // Calculate Top of the Firmware Device
  ldr   x2, PcdGet64 (PcdFdBaseAddress)
  ldr   w3, PcdGet32 (PcdFdSize)
  sub   x3, x3, #1
  add   x3, x3, x2      // x3 = FdTop = PcdFdBaseAddress + PcdFdSize

  // UEFI Memory Size (stacks are allocated in this region)
  LoadConstantToReg (FixedPcdGet32(PcdSystemMemoryUefiRegionSize), x4)

  //
  // 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  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)
  LoadConstantToReg (EFI_PAGE_MASK, x11)
  and   x11, x11, x1
  sub   x1, x1, x11

_GetBaseUefiMemory:
  // Calculate the Base of the UEFI Memory
  sub   x11, x1, x4

_GetStackBase:
  // r1 = The top of the Mpcore Stacks
  // Stack for the primary core = PrimaryCoreStack
  LoadConstantToReg (FixedPcdGet32(PcdCPUCorePrimaryStackSize), x2)
  sub   x12, x1, x2

  // Stack for the secondary core = Number of Cores - 1
  LoadConstantToReg (FixedPcdGet32(PcdCoreCount), x0)
  sub   x0, x0, #1
  LoadConstantToReg (FixedPcdGet32(PcdCPUCoreSecondaryStackSize), x1)
  mul   x1, x1, x0
  sub   x12, x12, x1

  // x12 = The base of the MpCore Stacks (primary stack & secondary stacks)
  mov   x0, x12
  mov   x1, x10
  //ArmPlatformStackSet(StackBase, MpId, PrimaryStackSize, SecondaryStackSize)
  LoadConstantToReg (FixedPcdGet32(PcdCPUCorePrimaryStackSize), x2)
  LoadConstantToReg (FixedPcdGet32(PcdCPUCoreSecondaryStackSize), x3)
  bl    ASM_PFX(ArmPlatformStackSet)

  // Is it the Primary Core ?
  mov   x0, x10
  bl    ASM_PFX(ArmPlatformIsPrimaryCore)
  cmp   x0, #1
  bne   _PrepareArguments

_ReserveGlobalVariable:
  LoadConstantToReg (FixedPcdGet32(PcdPeiGlobalVariableSize), x0)
  // InitializePrimaryStack($GlobalVariableSize, $Tmp1, $Tmp2)
  InitializePrimaryStack(x0, x1, x2)

_PrepareArguments:
  mov   x0, x10
  mov   x1, x11
  mov   x2, x12
  mov   x3, sp

  // Move sec startup address into a data register
  // Ensure we're jumping to FV version of the code (not boot remapped alias)
  ldr   x4, StartupAddr

  // Jump to PrePiCore C code
  //    x0 = MpId
  //    x1 = UefiMemoryBase
  //    x2 = StacksBase
  //    x3 = GlobalVariableBase
  blr   x4

_NeverReturn:
  b _NeverReturn