[mirror_edk2.git] / ArmPkg / Drivers / CpuDxe / ExceptionSupport.S

#------------------------------------------------------------------------------ 
#
# Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
#
# 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.
#
#------------------------------------------------------------------------------

.text
.align 3

GCC_ASM_EXPORT(ExceptionHandlersStart)
GCC_ASM_EXPORT(ExceptionHandlersEnd)
GCC_ASM_EXPORT(CommonExceptionEntry)
GCC_ASM_EXPORT(AsmCommonExceptionEntry)
GCC_ASM_EXPORT(CommonCExceptionHandler)

ASM_PFX(ExceptionHandlersStart):

ASM_PFX(Reset):
  b ASM_PFX(ResetEntry)

ASM_PFX(UndefinedInstruction):
  b ASM_PFX(UndefinedInstructionEntry)

ASM_PFX(SoftwareInterrupt):
  b ASM_PFX(SoftwareInterruptEntry)

ASM_PFX(PrefetchAbort):
  b ASM_PFX(PrefetchAbortEntry)

ASM_PFX(DataAbort):
  b ASM_PFX(DataAbortEntry)

ASM_PFX(ReservedException):
  b ASM_PFX(ReservedExceptionEntry)

ASM_PFX(Irq):
  b ASM_PFX(IrqEntry)

ASM_PFX(Fiq):
  b ASM_PFX(FiqEntry)

ASM_PFX(ResetEntry):
  srsdb     #0x13!                    @ Store return state on SVC stack
  stmfd     SP!,{LR}                  @ Store the link register for the current mode
  sub       SP,SP,#0x20               @ Save space for SP, LR, PC, IFAR - CPSR
  stmfd     SP!,{R0-R12}              @ Store the register state
  
  mov       R0,#0
  ldr       R1,ASM_PFX(CommonExceptionEntry)
  bx        R1

ASM_PFX(UndefinedInstructionEntry):
  srsdb     #0x13!                    @ Store return state on SVC stack
  cps       #0x13                     @ Switch to SVC for common stack
  stmfd     SP!,{LR}                  @ Store the link register for the current mode
  sub       SP,SP,#0x20               @ Save space for SP, LR, PC, IFAR - CPSR
  stmfd     SP!,{R0-R12}              @ Store the register state

  mov       r0,#1
  ldr       r1,ASM_PFX(CommonExceptionEntry)
  bx        r1

ASM_PFX(SoftwareInterruptEntry):
  srsdb     #0x13!                    @ Store return state on SVC stack
  stmfd     SP!,{LR}                  @ Store the link register for the current mode
  sub       SP,SP,#0x20               @ Save space for SP, LR, PC, IFAR - CPSR
  stmfd     SP!,{R0-R12}              @ Store the register state

  mov       r0,#2
  ldr       r1,ASM_PFX(CommonExceptionEntry)
  bx        r1

ASM_PFX(PrefetchAbortEntry):
  sub       LR,LR,#4
  srsdb     #0x13!                    @ Store return state on SVC stack
  cps       #0x13                     @ Switch to SVC for common stack
  stmfd     SP!,{LR}                  @ Store the link register for the current mode
  sub       SP,SP,#0x20               @ Save space for SP, LR, PC, IFAR - CPSR
  stmfd     SP!,{R0-R12}              @ Store the register state

  mov       r0,#3
  ldr       r1,ASM_PFX(CommonExceptionEntry)
  bx        r1

ASM_PFX(DataAbortEntry):
  sub       LR,LR,#8
  srsdb     #0x13!                    @ Store return state on SVC stack
  cps       #0x13                     @ Switch to SVC for common stack
  stmfd     SP!,{LR}                  @ Store the link register for the current mode
  sub       SP,SP,#0x20               @ Save space for SP, LR, PC, IFAR - CPSR
  stmfd     SP!,{R0-R12}              @ Store the register state

  mov       r0,#4
  ldr       r1,ASM_PFX(CommonExceptionEntry)
  bx        r1

ASM_PFX(ReservedExceptionEntry):
  srsdb     #0x13!                    @ Store return state on SVC stack
  cps       #0x13                     @ Switch to SVC for common stack
  stmfd     SP!,{LR}                  @ Store the link register for the current mode
  sub       SP,SP,#0x20               @ Save space for SP, LR, PC, IFAR - CPSR
  stmfd     SP!,{R0-R12}              @ Store the register state

  mov       r0,#5
  ldr       r1,ASM_PFX(CommonExceptionEntry)
  bx        r1

ASM_PFX(IrqEntry):
  sub       LR,LR,#4
  srsdb     #0x13!                    @ Store return state on SVC stack
  cps       #0x13                     @ Switch to SVC for common stack
  stmfd     SP!,{LR}                  @ Store the link register for the current mode
  sub       SP,SP,#0x20               @ Save space for SP, LR, PC, IFAR - CPSR
  stmfd     SP!,{R0-R12}              @ Store the register state

  mov       r0,#6
  ldr       r1,ASM_PFX(CommonExceptionEntry)
  bx        r1

ASM_PFX(FiqEntry):
  sub       LR,LR,#4
  srsdb     #0x13!                    @ Store return state on SVC stack
  cps       #0x13                     @ Switch to SVC for common stack
  stmfd     SP!,{LR}                  @ Store the link register for the current mode
  sub       SP,SP,#0x20               @ Save space for SP, LR, PC, IFAR - CPSR
  stmfd     SP!,{R0-R12}              @ Store the register state

  mov       r0,#7
  ldr       r1,ASM_PFX(CommonExceptionEntry)
  bx        r1

ASM_PFX(CommonExceptionEntry):
  .byte       0x12
  .byte       0x34
  .byte       0x56
  .byte       0x78

ASM_PFX(ExceptionHandlersEnd):

ASM_PFX(AsmCommonExceptionEntry):
  mrc       p15, 0, R1, c6, c0, 2   @ Read IFAR
  str       R1, [SP, #0x50]         @ Store it in EFI_SYSTEM_CONTEXT_ARM.IFAR 
  
  mrc       p15, 0, R1, c5, c0, 1   @ Read IFSR
  str       R1, [SP, #0x4c]         @ Store it in EFI_SYSTEM_CONTEXT_ARM.IFSR
  
  mrc       p15, 0, R1, c6, c0, 0   @ Read DFAR
  str       R1, [SP, #0x48]         @ Store it in EFI_SYSTEM_CONTEXT_ARM.DFAR
  
  mrc       p15, 0, R1, c5, c0, 0   @ Read DFSR
  str       R1, [SP, #0x44]         @ Store it in EFI_SYSTEM_CONTEXT_ARM.DFSR
  
  ldr       R1, [SP, #0x5c]         @ srsdb saved pre-exception CPSR on the stack 
  str       R1, [SP, #0x40]         @ Store it in EFI_SYSTEM_CONTEXT_ARM.CPSR
  and       r1, r1, #0x1f           @ Check to see if User or System Mode
  cmp       r1, #0x1f
  cmpne     r1, #0x10
  add       R2, SP, #0x38           @ Store it in EFI_SYSTEM_CONTEXT_ARM.LR
  ldmneed   r2, {lr}^               @ User or System mode, use unbanked register
  ldmneed   r2, {lr}                @ All other modes used banked register

  ldr       R1, [SP, #0x58]         @ PC is the LR pushed by srsdb 
  str       R1, [SP, #0x3c]         @ Store it in EFI_SYSTEM_CONTEXT_ARM.PC
  
  sub       R1, SP, #0x60           @ We pused 0x60 bytes on the stack 
  str       R1, [SP, #0x34]         @ Store it in EFI_SYSTEM_CONTEXT_ARM.SP
  
                                              @ R0 is exception type 
  mov       R1,SP                             @ Prepare System Context pointer as an argument for the exception handler
  blx       ASM_PFX(CommonCExceptionHandler)  @ Call exception handler
  
  ldr       R2,[SP,#0x40]           @ EFI_SYSTEM_CONTEXT_ARM.CPSR
  str       R2,[SP,#0x5c]           @ Store it back to srsdb stack slot so it can be restored 

  ldr       R2,[SP,#0x3c]           @ EFI_SYSTEM_CONTEXT_ARM.PC
  str       R2,[SP,#0x58]           @ Store it back to srsdb stack slot so it can be restored 

  ldmfd     SP!,{R0-R12}            @ Restore general purpose registers
                                    @ Exception handler can not change SP or LR as we would blow chunks
                                    
  add       SP,SP,#0x20             @ Clear out the remaining stack space
  ldmfd     SP!,{LR}                @ restore the link register for this context
  rfefd     SP!                     @ return from exception via srsdb stack slot
Commit	Line	Data
2ef2b01e A	1	#------------------------------------------------------------------------------
2ef2b01e A	2	#
d6ebcab7	3	# Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
2ef2b01e	4	#
d6ebcab7	5	# This program and the accompanying materials
2ef2b01e A	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
1bfda055	18	GCC_ASM_EXPORT(ExceptionHandlersStart)
	19	GCC_ASM_EXPORT(ExceptionHandlersEnd)
	20	GCC_ASM_EXPORT(CommonExceptionEntry)
	21	GCC_ASM_EXPORT(AsmCommonExceptionEntry)
	22	GCC_ASM_EXPORT(CommonCExceptionHandler)
2ef2b01e A	23
	24	ASM_PFX(ExceptionHandlersStart):
	25
	26	ASM_PFX(Reset):
	27	b ASM_PFX(ResetEntry)
	28
	29	ASM_PFX(UndefinedInstruction):
	30	b ASM_PFX(UndefinedInstructionEntry)
	31
	32	ASM_PFX(SoftwareInterrupt):
	33	b ASM_PFX(SoftwareInterruptEntry)
	34
	35	ASM_PFX(PrefetchAbort):
	36	b ASM_PFX(PrefetchAbortEntry)
	37
	38	ASM_PFX(DataAbort):
	39	b ASM_PFX(DataAbortEntry)
	40
	41	ASM_PFX(ReservedException):
	42	b ASM_PFX(ReservedExceptionEntry)
	43
	44	ASM_PFX(Irq):
	45	b ASM_PFX(IrqEntry)
	46
	47	ASM_PFX(Fiq):
	48	b ASM_PFX(FiqEntry)
	49
	50	ASM_PFX(ResetEntry):
8a4d81e6 A	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
2ef2b01e A	59
2ef2b01e A	60	ASM_PFX(UndefinedInstructionEntry):
8a4d81e6 A	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
2ef2b01e A	67	mov r0,#1
	68	ldr r1,ASM_PFX(CommonExceptionEntry)
	69	bx r1
	70
	71	ASM_PFX(SoftwareInterruptEntry):
8a4d81e6 A	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
2ef2b01e A	77	mov r0,#2
	78	ldr r1,ASM_PFX(CommonExceptionEntry)
	79	bx r1
	80
	81	ASM_PFX(PrefetchAbortEntry):
8a4d81e6 A	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
2ef2b01e	89	mov r0,#3
2ef2b01e A	90	ldr r1,ASM_PFX(CommonExceptionEntry)
	91	bx r1
	92
	93	ASM_PFX(DataAbortEntry):
8a4d81e6 A	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
2ef2b01e	101	mov r0,#4
2ef2b01e A	102	ldr r1,ASM_PFX(CommonExceptionEntry)
	103	bx r1
	104
	105	ASM_PFX(ReservedExceptionEntry):
8a4d81e6 A	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
2ef2b01e A	112	mov r0,#5
	113	ldr r1,ASM_PFX(CommonExceptionEntry)
	114	bx r1
	115
	116	ASM_PFX(IrqEntry):
8a4d81e6 A	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
2ef2b01e	124	mov r0,#6
2ef2b01e A	125	ldr r1,ASM_PFX(CommonExceptionEntry)
	126	bx r1
	127
	128	ASM_PFX(FiqEntry):
8a4d81e6 A	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
2ef2b01e	136	mov r0,#7
2ef2b01e A	137	ldr r1,ASM_PFX(CommonExceptionEntry)
	138	bx r1
	139
	140	ASM_PFX(CommonExceptionEntry):
	141	.byte 0x12
	142	.byte 0x34
	143	.byte 0x56
	144	.byte 0x78
	145
	146	ASM_PFX(ExceptionHandlersEnd):
	147
	148	ASM_PFX(AsmCommonExceptionEntry):
8a4d81e6 A	149	mrc p15, 0, R1, c6, c0, 2 @ Read IFAR
8a4d81e6 A	150	str R1, [SP, #0x50] @ Store it in EFI_SYSTEM_CONTEXT_ARM.IFAR
2ef2b01e	151
8a4d81e6 A	152	mrc p15, 0, R1, c5, c0, 1 @ Read IFSR
8a4d81e6 A	153	str R1, [SP, #0x4c] @ Store it in EFI_SYSTEM_CONTEXT_ARM.IFSR
2ef2b01e	154
8a4d81e6 A	155	mrc p15, 0, R1, c6, c0, 0 @ Read DFAR
8a4d81e6 A	156	str R1, [SP, #0x48] @ Store it in EFI_SYSTEM_CONTEXT_ARM.DFAR
2ef2b01e	157
8a4d81e6 A	158	mrc p15, 0, R1, c5, c0, 0 @ Read DFSR
8a4d81e6 A	159	str R1, [SP, #0x44] @ Store it in EFI_SYSTEM_CONTEXT_ARM.DFSR
2ef2b01e	160
8a4d81e6 A	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
2ef2b01e	172
8a4d81e6 A	173	sub R1, SP, #0x60 @ We pused 0x60 bytes on the stack
8a4d81e6 A	174	str R1, [SP, #0x34] @ Store it in EFI_SYSTEM_CONTEXT_ARM.SP
2ef2b01e	175
8a4d81e6 A	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
2ef2b01e	179
8a4d81e6 A	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