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/*
* ARCv2 ISA based core Low Level Intr/Traps/Exceptions(non-TLB) Handling
*
* Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/linkage.h> /* ARC_{EXTRY,EXIT} */
#include <asm/entry.h> /* SAVE_ALL_{INT1,INT2,TRAP...} */
#include <asm/errno.h>
#include <asm/arcregs.h>
#include <asm/irqflags.h>
.cpu HS
#define VECTOR .word
;############################ Vector Table #################################
.section .vector,"a",@progbits
.align 4
# Initial 16 slots are Exception Vectors
VECTOR stext ; Restart Vector (jump to entry point)
VECTOR mem_service ; Mem exception
VECTOR instr_service ; Instrn Error
VECTOR EV_MachineCheck ; Fatal Machine check
VECTOR EV_TLBMissI ; Intruction TLB miss
VECTOR EV_TLBMissD ; Data TLB miss
VECTOR EV_TLBProtV ; Protection Violation
VECTOR EV_PrivilegeV ; Privilege Violation
VECTOR EV_SWI ; Software Breakpoint
VECTOR EV_Trap ; Trap exception
VECTOR EV_Extension ; Extn Instruction Exception
VECTOR EV_DivZero ; Divide by Zero
VECTOR EV_DCError ; Data Cache Error
VECTOR EV_Misaligned ; Misaligned Data Access
VECTOR reserved ; Reserved slots
VECTOR reserved ; Reserved slots
# Begin Interrupt Vectors
VECTOR handle_interrupt ; (16) Timer0
VECTOR handle_interrupt ; unused (Timer1)
VECTOR handle_interrupt ; unused (WDT)
VECTOR handle_interrupt ; (19) ICI (inter core interrupt)
VECTOR handle_interrupt
VECTOR handle_interrupt
VECTOR handle_interrupt
VECTOR handle_interrupt ; (23) End of fixed IRQs
.rept CONFIG_ARC_NUMBER_OF_INTERRUPTS - 8
VECTOR handle_interrupt
.endr
.section .text, "ax",@progbits
res_service: ; processor restart
flag 0x1 ; not implemented
nop
nop
reserved: ; processor restart
rtie ; jump to processor initializations
;##################### Interrupt Handling ##############################
ENTRY(handle_interrupt)
INTERRUPT_PROLOGUE irq
clri ; To make status32.IE agree with CPU internal state
lr r0, [ICAUSE]
mov blink, ret_from_exception
b.d arch_do_IRQ
mov r1, sp
END(handle_interrupt)
;################### Non TLB Exception Handling #############################
ENTRY(EV_SWI)
flag 1
END(EV_SWI)
ENTRY(EV_DivZero)
flag 1
END(EV_DivZero)
ENTRY(EV_DCError)
flag 1
END(EV_DCError)
ENTRY(EV_Misaligned)
EXCEPTION_PROLOGUE
lr r0, [efa] ; Faulting Data address
mov r1, sp
FAKE_RET_FROM_EXCPN
SAVE_CALLEE_SAVED_USER
mov r2, sp ; callee_regs
bl do_misaligned_access
; TBD: optimize - do this only if a callee reg was involved
; either a dst of emulated LD/ST or src with address-writeback
RESTORE_CALLEE_SAVED_USER
b ret_from_exception
END(EV_Misaligned)
; ---------------------------------------------
; Protection Violation Exception Handler
; ---------------------------------------------
ENTRY(EV_TLBProtV)
EXCEPTION_PROLOGUE
lr r0, [efa] ; Faulting Data address
mov r1, sp ; pt_regs
FAKE_RET_FROM_EXCPN
mov blink, ret_from_exception
b do_page_fault
END(EV_TLBProtV)
; From Linux standpoint Slow Path I/D TLB Miss is same a ProtV as they
; need to call do_page_fault().
; ECR in pt_regs provides whether access was R/W/X
.global call_do_page_fault
.set call_do_page_fault, EV_TLBProtV
;############# Common Handlers for ARCompact and ARCv2 ##############
#include "entry.S"
;############# Return from Intr/Excp/Trap (ARCv2 ISA Specifics) ##############
;
; Restore the saved sys context (common exit-path for EXCPN/IRQ/Trap)
; IRQ shd definitely not happen between now and rtie
; All 2 entry points to here already disable interrupts
.Lrestore_regs:
ld r0, [sp, PT_status32] ; U/K mode at time of entry
lr r10, [AUX_IRQ_ACT]
bmsk r11, r10, 15 ; AUX_IRQ_ACT.ACTIVE
breq r11, 0, .Lexcept_ret ; No intr active, ret from Exception
;####### Return from Intr #######
debug_marker_l1:
; Handle special case #1: (Entry via Exception, Return via IRQ)
;
; Exception in U mode, preempted in kernel, Intr taken (K mode), orig
; task now returning to U mode (riding the Intr)
; AUX_IRQ_ACTIVE won't have U bit set (since intr in K mode), hence SP
; won't be switched to correct U mode value (from AUX_SP)
; So force AUX_IRQ_ACT.U for such a case
btst r0, STATUS_U_BIT ; Z flag set if K (Z clear for U)
bset.nz r11, r11, AUX_IRQ_ACT_BIT_U ; NZ means U
sr r11, [AUX_IRQ_ACT]
INTERRUPT_EPILOGUE irq
rtie
;####### Return from Exception / pure kernel mode #######
.Lexcept_ret: ; Expects r0 has PT_status32
debug_marker_syscall:
EXCEPTION_EPILOGUE
rtie
END(ret_from_exception)
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