diff options
Diffstat (limited to 'EmbeddedPkg/Library/GdbDebugAgent/Arm/ExceptionSupport.ARMv6.asm')
| -rwxr-xr-x | EmbeddedPkg/Library/GdbDebugAgent/Arm/ExceptionSupport.ARMv6.asm | 259 |
1 files changed, 259 insertions, 0 deletions
diff --git a/EmbeddedPkg/Library/GdbDebugAgent/Arm/ExceptionSupport.ARMv6.asm b/EmbeddedPkg/Library/GdbDebugAgent/Arm/ExceptionSupport.ARMv6.asm new file mode 100755 index 0000000000..3dccf5b077 --- /dev/null +++ b/EmbeddedPkg/Library/GdbDebugAgent/Arm/ExceptionSupport.ARMv6.asm @@ -0,0 +1,259 @@ +//------------------------------------------------------------------------------ +// +// 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 + + */ + + + EXPORT ExceptionHandlersStart + EXPORT ExceptionHandlersEnd + EXPORT CommonExceptionEntry + EXPORT AsmCommonExceptionEntry + IMPORT GdbExceptionHandler + + PRESERVE8 + AREA DxeExceptionHandlers, CODE, READONLY + +// +// This code gets copied to the ARM vector table +// ExceptionHandlersStart - ExceptionHandlersEnd gets copied +// +ExceptionHandlersStart + +Reset + b Reset + +UndefinedInstruction + b UndefinedInstructionEntry + +SoftwareInterrupt + b SoftwareInterruptEntry + +PrefetchAbort + b PrefetchAbortEntry + +DataAbort + b DataAbortEntry + +ReservedException + b ReservedExceptionEntry + +Irq + b Irq + +Fiq + b FiqEntry + + +UndefinedInstructionEntry + sub LR, LR, #4 ; Only -2 for Thumb, adjust in CommonExceptionEntry + srsfd #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,CommonExceptionEntry; + bx R1 + +SoftwareInterruptEntry + sub LR, LR, #4 ; Only -2 for Thumb, adjust in CommonExceptionEntry + srsfd #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,CommonExceptionEntry + bx R1 + +PrefetchAbortEntry + sub LR,LR,#4 + srsfd #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,CommonExceptionEntry + bx R1 + +DataAbortEntry + sub LR,LR,#8 + srsfd #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 ; ExceptionType + ldr R1,CommonExceptionEntry + bx R1 + +ReservedExceptionEntry + srsfd #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 ; ExceptionType + ldr R1,CommonExceptionEntry + bx R1 + +FiqEntry + sub LR,LR,#4 + srsfd #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,CommonExceptionEntry + bx R1 + +// +// This gets patched by the C code that patches in the vector table +// +CommonExceptionEntry + dcd 0x12345678 + +ExceptionHandlersEnd + +// +// This code runs from CpuDxe driver loaded address. It is patched into +// CommonExceptionEntry. +// +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] ; srsfd 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 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 + + END + + |