diff options
Diffstat (limited to 'EmbeddedPkg/Library/GdbDebugAgent/Arm/ExceptionSupport.ARMv6.S')
| -rwxr-xr-x | EmbeddedPkg/Library/GdbDebugAgent/Arm/ExceptionSupport.ARMv6.S | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/EmbeddedPkg/Library/GdbDebugAgent/Arm/ExceptionSupport.ARMv6.S b/EmbeddedPkg/Library/GdbDebugAgent/Arm/ExceptionSupport.ARMv6.S new file mode 100755 index 0000000000..bb4d17c5ad --- /dev/null +++ b/EmbeddedPkg/Library/GdbDebugAgent/Arm/ExceptionSupport.ARMv6.S @@ -0,0 +1,258 @@ +#------------------------------------------------------------------------------ +# +# Use ARMv6 instruction to operate on a single stack +# +# Copyright (c) 2008-2010 Apple Inc. All rights reserved. +# +# 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. +# +#------------------------------------------------------------------------------ + +/* + +This is the stack constructed by the exception handler (low address to high address) + # R0 - IFAR is EFI_SYSTEM_CONTEXT for ARM + Reg Offset + === ====== + R0 0x00 # stmfd SP!,{R0-R12} + R1 0x04 + R2 0x08 + R3 0x0c + R4 0x10 + R5 0x14 + R6 0x18 + R7 0x1c + R8 0x20 + R9 0x24 + R10 0x28 + R11 0x2c + R12 0x30 + SP 0x34 # reserved via adding 0x20 (32) to the SP + LR 0x38 + PC 0x3c + CPSR 0x40 + DFSR 0x44 + DFAR 0x48 + IFSR 0x4c + IFAR 0x50 + + LR 0x54 # SVC Link register (we need to restore it) + + LR 0x58 # pushed by srsfd + CPSR 0x5c + + */ + + +.globl ASM_PFX(ExceptionHandlersStart) +.globl ASM_PFX(ExceptionHandlersEnd) +.globl ASM_PFX(CommonExceptionEntry) +.globl ASM_PFX(AsmCommonExceptionEntry) +.globl ASM_PFX(GdbExceptionHandler) + +.text +.align 3 + + +// +// This code gets copied to the ARM vector table +// ExceptionHandlersStart - ExceptionHandlersEnd gets copied +// +ASM_PFX(ExceptionHandlersStart): + +ASM_PFX(Reset): + b ASM_PFX(Reset) + +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(Irq) + +ASM_PFX(Fiq): + b ASM_PFX(FiqEntry) + + +ASM_PFX(UndefinedInstructionEntry): + sub LR, LR, #4 @ Only -2 for Thumb, adjust in CommonExceptionEntry + 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 @ ExceptionType + ldr R1,ASM_PFX(CommonExceptionEntry) + bx R1 + +ASM_PFX(SoftwareInterruptEntry): + sub LR, LR, #4 @ Only -2 for Thumb, adjust in CommonExceptionEntry + srsdb #0x13! @ Store return state on SVC stack + @ We are already in SVC mode + 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 @ ExceptionType + 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 @ ExceptionType + 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(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 + @ Since we have already switch to SVC R8_fiq - R12_fiq + @ never get used or saved + mov R0,#7 @ ExceptionType + ldr R1,ASM_PFX(CommonExceptionEntry) + bx R1 + +// +// This gets patched by the C code that patches in the vector table +// +ASM_PFX(CommonExceptionEntry): + .byte 0x12 + .byte 0x34 + .byte 0x56 + .byte 0x78 + +ASM_PFX(ExceptionHandlersEnd): + +// +// This code runs from CpuDxe driver loaded address. It is patched into +// CommonExceptionEntry. +// +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 + + add R2, SP, #0x38 @ Make R2 point to EFI_SYSTEM_CONTEXT_ARM.LR + and R3, R1, #0x1f @ Check CPSR to see if User or System Mode + cmp R3, #0x1f @ if ((CPSR == 0x10) || (CPSR == 0x1df)) + cmpne R3, #0x10 @ + stmeqed R2, {lr}^ @ save unbanked lr + @ else + stmneed R2, {lr} @ save SVC lr + + + ldr R5, [SP, #0x58] @ PC is the LR pushed by srsfd + @ Check to see if we have to adjust for Thumb entry + sub r4, r0, #1 @ if (ExceptionType == 1 || ExceptionType ==2)) { + cmp r4, #1 @ // UND & SVC have differnt LR adjust for Thumb + bhi NoAdjustNeeded + + tst r1, #0x20 @ if ((CPSR & T)) == T) { // Thumb Mode on entry + addne R5, R5, #2 @ PC += 2@ + str R5,[SP,#0x58] @ Update LR value pused by srsfd + +NoAdjustNeeded: + + str R5, [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 ExceptionType + mov R1,SP @ R1 is SystemContext + +/* +VOID +EFIAPI +GdbExceptionHandler ( + IN EFI_EXCEPTION_TYPE ExceptionType, R0 + IN OUT EFI_SYSTEM_CONTEXT SystemContext R1 + ) + +*/ + blx ASM_PFX(GdbExceptionHandler) @ Call exception handler + + ldr R1,[SP,#0x3c] @ EFI_SYSTEM_CONTEXT_ARM.PC + str R1,[SP,#0x58] @ Store it back to srsfd stack slot so it can be restored + + ldr R1,[SP,#0x40] @ EFI_SYSTEM_CONTEXT_ARM.CPSR + str R1,[SP,#0x5c] @ Store it back to srsfd stack slot so it can be restored + + add R3, SP, #0x54 @ Make R3 point to SVC LR saved on entry + add R2, SP, #0x38 @ Make R2 point to EFI_SYSTEM_CONTEXT_ARM.LR + and R1, R1, #0x1f @ Check to see if User or System Mode + cmp R1, #0x1f @ if ((CPSR == 0x10) || (CPSR == 0x1f)) + cmpne R1, #0x10 @ + ldmeqed R2, {lr}^ @ restore unbanked lr + @ else + ldmneed R3, {lr} @ restore SVC lr, via ldmfd SP!, {LR} + + ldmfd SP!,{R0-R12} @ Restore general purpose registers + @ Exception handler can not change SP + + 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 srsfd stack slot + |