1#------------------------------------------------------------------------------
2#
3# Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
4#
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
9#
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.
12#
13#------------------------------------------------------------------------------
14
15.text
16.align 3
17
18GCC_ASM_EXPORT(ExceptionHandlersStart)
19GCC_ASM_EXPORT(ExceptionHandlersEnd)
20GCC_ASM_EXPORT(CommonExceptionEntry)
21GCC_ASM_EXPORT(AsmCommonExceptionEntry)
22GCC_ASM_EXPORT(CommonCExceptionHandler)
23
24ASM_PFX(ExceptionHandlersStart):
25
26ASM_PFX(Reset):
27  b ASM_PFX(ResetEntry)
28
29ASM_PFX(UndefinedInstruction):
30  b ASM_PFX(UndefinedInstructionEntry)
31
32ASM_PFX(SoftwareInterrupt):
33  b ASM_PFX(SoftwareInterruptEntry)
34
35ASM_PFX(PrefetchAbort):
36  b ASM_PFX(PrefetchAbortEntry)
37
38ASM_PFX(DataAbort):
39  b ASM_PFX(DataAbortEntry)
40
41ASM_PFX(ReservedException):
42  b ASM_PFX(ReservedExceptionEntry)
43
44ASM_PFX(Irq):
45  b ASM_PFX(IrqEntry)
46
47ASM_PFX(Fiq):
48  b ASM_PFX(FiqEntry)
49
50ASM_PFX(ResetEntry):
51  srsdb     #0x13!                    @ Store return state on SVC stack
52  stmfd     SP!,{LR}                  @ Store the link register for the current mode
53  sub       SP,SP,#0x20               @ Save space for SP, LR, PC, IFAR - CPSR
54  stmfd     SP!,{R0-R12}              @ Store the register state
55
56  mov       R0,#0
57  ldr       R1,ASM_PFX(CommonExceptionEntry)
58  bx        R1
59
60ASM_PFX(UndefinedInstructionEntry):
61  srsdb     #0x13!                    @ Store return state on SVC stack
62  cps       #0x13                     @ Switch to SVC for common stack
63  stmfd     SP!,{LR}                  @ Store the link register for the current mode
64  sub       SP,SP,#0x20               @ Save space for SP, LR, PC, IFAR - CPSR
65  stmfd     SP!,{R0-R12}              @ Store the register state
66
67  mov       r0,#1
68  ldr       r1,ASM_PFX(CommonExceptionEntry)
69  bx        r1
70
71ASM_PFX(SoftwareInterruptEntry):
72  srsdb     #0x13!                    @ Store return state on SVC stack
73  stmfd     SP!,{LR}                  @ Store the link register for the current mode
74  sub       SP,SP,#0x20               @ Save space for SP, LR, PC, IFAR - CPSR
75  stmfd     SP!,{R0-R12}              @ Store the register state
76
77  mov       r0,#2
78  ldr       r1,ASM_PFX(CommonExceptionEntry)
79  bx        r1
80
81ASM_PFX(PrefetchAbortEntry):
82  sub       LR,LR,#4
83  srsdb     #0x13!                    @ Store return state on SVC stack
84  cps       #0x13                     @ Switch to SVC for common stack
85  stmfd     SP!,{LR}                  @ Store the link register for the current mode
86  sub       SP,SP,#0x20               @ Save space for SP, LR, PC, IFAR - CPSR
87  stmfd     SP!,{R0-R12}              @ Store the register state
88
89  mov       r0,#3
90  ldr       r1,ASM_PFX(CommonExceptionEntry)
91  bx        r1
92
93ASM_PFX(DataAbortEntry):
94  sub       LR,LR,#8
95  srsdb     #0x13!                    @ Store return state on SVC stack
96  cps       #0x13                     @ Switch to SVC for common stack
97  stmfd     SP!,{LR}                  @ Store the link register for the current mode
98  sub       SP,SP,#0x20               @ Save space for SP, LR, PC, IFAR - CPSR
99  stmfd     SP!,{R0-R12}              @ Store the register state
100
101  mov       r0,#4
102  ldr       r1,ASM_PFX(CommonExceptionEntry)
103  bx        r1
104
105ASM_PFX(ReservedExceptionEntry):
106  srsdb     #0x13!                    @ Store return state on SVC stack
107  cps       #0x13                     @ Switch to SVC for common stack
108  stmfd     SP!,{LR}                  @ Store the link register for the current mode
109  sub       SP,SP,#0x20               @ Save space for SP, LR, PC, IFAR - CPSR
110  stmfd     SP!,{R0-R12}              @ Store the register state
111
112  mov       r0,#5
113  ldr       r1,ASM_PFX(CommonExceptionEntry)
114  bx        r1
115
116ASM_PFX(IrqEntry):
117  sub       LR,LR,#4
118  srsdb     #0x13!                    @ Store return state on SVC stack
119  cps       #0x13                     @ Switch to SVC for common stack
120  stmfd     SP!,{LR}                  @ Store the link register for the current mode
121  sub       SP,SP,#0x20               @ Save space for SP, LR, PC, IFAR - CPSR
122  stmfd     SP!,{R0-R12}              @ Store the register state
123
124  mov       r0,#6
125  ldr       r1,ASM_PFX(CommonExceptionEntry)
126  bx        r1
127
128ASM_PFX(FiqEntry):
129  sub       LR,LR,#4
130  srsdb     #0x13!                    @ Store return state on SVC stack
131  cps       #0x13                     @ Switch to SVC for common stack
132  stmfd     SP!,{LR}                  @ Store the link register for the current mode
133  sub       SP,SP,#0x20               @ Save space for SP, LR, PC, IFAR - CPSR
134  stmfd     SP!,{R0-R12}              @ Store the register state
135
136  mov       r0,#7
137  ldr       r1,ASM_PFX(CommonExceptionEntry)
138  bx        r1
139
140ASM_PFX(CommonExceptionEntry):
141  .byte       0x12
142  .byte       0x34
143  .byte       0x56
144  .byte       0x78
145
146ASM_PFX(ExceptionHandlersEnd):
147
148ASM_PFX(AsmCommonExceptionEntry):
149  mrc       p15, 0, R1, c6, c0, 2   @ Read IFAR
150  str       R1, [SP, #0x50]         @ Store it in EFI_SYSTEM_CONTEXT_ARM.IFAR
151
152  mrc       p15, 0, R1, c5, c0, 1   @ Read IFSR
153  str       R1, [SP, #0x4c]         @ Store it in EFI_SYSTEM_CONTEXT_ARM.IFSR
154
155  mrc       p15, 0, R1, c6, c0, 0   @ Read DFAR
156  str       R1, [SP, #0x48]         @ Store it in EFI_SYSTEM_CONTEXT_ARM.DFAR
157
158  mrc       p15, 0, R1, c5, c0, 0   @ Read DFSR
159  str       R1, [SP, #0x44]         @ Store it in EFI_SYSTEM_CONTEXT_ARM.DFSR
160
161  ldr       R1, [SP, #0x5c]         @ srsdb saved pre-exception CPSR on the stack
162  str       R1, [SP, #0x40]         @ Store it in EFI_SYSTEM_CONTEXT_ARM.CPSR
163  and       r1, r1, #0x1f           @ Check to see if User or System Mode
164  cmp       r1, #0x1f
165  cmpne     r1, #0x10
166  add       R2, SP, #0x38           @ Store it in EFI_SYSTEM_CONTEXT_ARM.LR
167  ldmneed   r2, {lr}^               @ User or System mode, use unbanked register
168  ldmneed   r2, {lr}                @ All other modes used banked register
169
170  ldr       R1, [SP, #0x58]         @ PC is the LR pushed by srsdb
171  str       R1, [SP, #0x3c]         @ Store it in EFI_SYSTEM_CONTEXT_ARM.PC
172
173  sub       R1, SP, #0x60           @ We pused 0x60 bytes on the stack
174  str       R1, [SP, #0x34]         @ Store it in EFI_SYSTEM_CONTEXT_ARM.SP
175
176                                              @ R0 is exception type
177  mov       R1,SP                             @ Prepare System Context pointer as an argument for the exception handler
178  blx       ASM_PFX(CommonCExceptionHandler)  @ Call exception handler
179
180  ldr       R2,[SP,#0x40]           @ EFI_SYSTEM_CONTEXT_ARM.CPSR
181  str       R2,[SP,#0x5c]           @ Store it back to srsdb stack slot so it can be restored
182
183  ldr       R2,[SP,#0x3c]           @ EFI_SYSTEM_CONTEXT_ARM.PC
184  str       R2,[SP,#0x58]           @ Store it back to srsdb stack slot so it can be restored
185
186  ldmfd     SP!,{R0-R12}            @ Restore general purpose registers
187                                    @ Exception handler can not change SP or LR as we would blow chunks
188
189  add       SP,SP,#0x20             @ Clear out the remaining stack space
190  ldmfd     SP!,{LR}                @ restore the link register for this context
191  rfefd     SP!                     @ return from exception via srsdb stack slot
192