/*
- * Low Level Interrupts/Traps/Exceptions(non-TLB) Handling for ARC
+ * Common Low Level Interrupts/Traps/Exceptions(non-TLB) Handling for ARC
+ * (included from entry-<isa>.S
*
+ * Copyright (C) 2014-15 Synopsys, Inc. (www.synopsys.com)
* Copyright (C) 2004, 2007-2010, 2011-2012 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.
- *
- * vineetg: May 2011
- * -Userspace unaligned access emulation
- *
- * vineetg: Feb 2011 (ptrace low level code fixes)
- * -traced syscall return code (r0) was not saved into pt_regs for restoring
- * into user reg-file when traded task rets to user space.
- * -syscalls needing arch-wrappers (mainly for passing sp as pt_regs)
- * were not invoking post-syscall trace hook (jumping directly into
- * ret_from_system_call)
- *
- * vineetg: Nov 2010:
- * -Vector table jumps (@8 bytes) converted into branches (@4 bytes)
- * -To maintain the slot size of 8 bytes/vector, added nop, which is
- * not executed at runtime.
- *
- * vineetg: Nov 2009 (Everything needed for TIF_RESTORE_SIGMASK)
- * -do_signal()invoked upon TIF_RESTORE_SIGMASK as well
- * -Wrappers for sys_{,rt_}sigsuspend() nolonger needed as they don't
- * need ptregs anymore
- *
- * Vineetg: Oct 2009
- * -In a rare scenario, Process gets a Priv-V exception and gets scheduled
- * out. Since we don't do FAKE RTIE for Priv-V, CPU excpetion state remains
- * active (AE bit enabled). This causes a double fault for a subseq valid
- * exception. Thus FAKE RTIE needed in low level Priv-Violation handler.
- * Instr Error could also cause similar scenario, so same there as well.
- *
- * Vineetg: March 2009 (Supporting 2 levels of Interrupts)
- *
- * Vineetg: Aug 28th 2008: Bug #94984
- * -Zero Overhead Loop Context shd be cleared when entering IRQ/EXcp/Trap
- * Normally CPU does this automatically, however when doing FAKE rtie,
- * we need to explicitly do this. The problem in macros
- * FAKE_RET_FROM_EXCPN and FAKE_RET_FROM_EXCPN_LOCK_IRQ was that this bit
- * was being "CLEARED" rather then "SET". Since it is Loop INHIBIT Bit,
- * setting it and not clearing it clears ZOL context
- *
- * Vineetg: May 16th, 2008
- * - r25 now contains the Current Task when in kernel
- *
- * Vineetg: Dec 22, 2007
- * Minor Surgery of Low Level ISR to make it SMP safe
- * - MMU_SCRATCH0 Reg used for freeing up r9 in Level 1 ISR
- * - _current_task is made an array of NR_CPUS
- * - Access of _current_task wrapped inside a macro so that if hardware
- * team agrees for a dedicated reg, no other code is touched
- *
- * Amit Bhor, Rahul Trivedi, Kanika Nema, Sameer Dhavale : Codito Tech 2004
*/
/*------------------------------------------------------------------
* Global Pointer (gp) r26
* Frame Pointer (fp) r27
* Stack Pointer (sp) r28
- * Interrupt link register (ilink1) r29
- * Interrupt link register (ilink2) r30
* Branch link register (blink) r31
*------------------------------------------------------------------
*/
- .cpu A7
-
-;############################ Vector Table #################################
-
-.macro VECTOR lbl
-#if 1 /* Just in case, build breaks */
- j \lbl
-#else
- b \lbl
- nop
-#endif
-.endm
-
- .section .vector, "ax",@progbits
- .align 4
-
-/* Each entry in the vector table must occupy 2 words. Since it is a jump
- * across sections (.vector to .text) we are gauranteed that 'j somewhere'
- * will use the 'j limm' form of the intrsuction as long as somewhere is in
- * a section other than .vector.
- */
-
-; ********* Critical System Events **********************
-VECTOR res_service ; 0x0, Restart Vector (0x0)
-VECTOR mem_service ; 0x8, Mem exception (0x1)
-VECTOR instr_service ; 0x10, Instrn Error (0x2)
-
-; ******************** Device ISRs **********************
-#ifdef CONFIG_ARC_IRQ3_LV2
-VECTOR handle_interrupt_level2
-#else
-VECTOR handle_interrupt_level1
-#endif
-
-VECTOR handle_interrupt_level1
-
-#ifdef CONFIG_ARC_IRQ5_LV2
-VECTOR handle_interrupt_level2
-#else
-VECTOR handle_interrupt_level1
-#endif
-
-#ifdef CONFIG_ARC_IRQ6_LV2
-VECTOR handle_interrupt_level2
-#else
-VECTOR handle_interrupt_level1
-#endif
-
-.rept 25
-VECTOR handle_interrupt_level1 ; Other devices
-.endr
-
-/* FOR ARC600: timer = 0x3, uart = 0x8, emac = 0x10 */
-
-; ******************** Exceptions **********************
-VECTOR EV_MachineCheck ; 0x100, Fatal Machine check (0x20)
-VECTOR EV_TLBMissI ; 0x108, Intruction TLB miss (0x21)
-VECTOR EV_TLBMissD ; 0x110, Data TLB miss (0x22)
-VECTOR EV_TLBProtV ; 0x118, Protection Violation (0x23)
- ; or Misaligned Access
-VECTOR EV_PrivilegeV ; 0x120, Privilege Violation (0x24)
-VECTOR EV_Trap ; 0x128, Trap exception (0x25)
-VECTOR EV_Extension ; 0x130, Extn Intruction Excp (0x26)
-
-.rept 24
-VECTOR reserved ; Reserved Exceptions
-.endr
-
-#include <linux/linkage.h> /* {EXTRY,EXIT} */
-#include <asm/entry.h> /* SAVE_ALL_{INT1,INT2,SYS...} */
-#include <asm/errno.h>
-#include <asm/arcregs.h>
-#include <asm/irqflags.h>
-
-;##################### Scratch Mem for IRQ stack switching #############
-
-ARCFP_DATA int1_saved_reg
- .align 32
- .type int1_saved_reg, @object
- .size int1_saved_reg, 4
-int1_saved_reg:
- .zero 4
-
-/* Each Interrupt level needs its own scratch */
-#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS
-
-ARCFP_DATA int2_saved_reg
- .type int2_saved_reg, @object
- .size int2_saved_reg, 4
-int2_saved_reg:
- .zero 4
-
-#endif
-
-; ---------------------------------------------
- .section .text, "ax",@progbits
-
-res_service: ; processor restart
- flag 0x1 ; not implemented
- nop
- nop
-
-reserved: ; processor restart
- rtie ; jump to processor initializations
-
-;##################### Interrupt Handling ##############################
-
-#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS
-; ---------------------------------------------
-; Level 2 ISR: Can interrupt a Level 1 ISR
-; ---------------------------------------------
-ENTRY(handle_interrupt_level2)
+;################### Special Sys Call Wrappers ##########################
- ; TODO-vineetg for SMP this wont work
- ; free up r9 as scratchpad
- st r9, [@int2_saved_reg]
+ENTRY(sys_clone_wrapper)
+ SAVE_CALLEE_SAVED_USER
+ bl @sys_clone
+ DISCARD_CALLEE_SAVED_USER
- ;Which mode (user/kernel) was the system in when intr occured
- lr r9, [status32_l2]
+ GET_CURR_THR_INFO_FLAGS r10
+ btst r10, TIF_SYSCALL_TRACE
+ bnz tracesys_exit
- SWITCH_TO_KERNEL_STK
- SAVE_ALL_INT2
+ b ret_from_system_call
+END(sys_clone_wrapper)
- ;------------------------------------------------------
- ; if L2 IRQ interrupted a L1 ISR, disable preemption
- ;------------------------------------------------------
+ENTRY(ret_from_fork)
+ ; when the forked child comes here from the __switch_to function
+ ; r0 has the last task pointer.
+ ; put last task in scheduler queue
+ jl @schedule_tail
- ld r9, [sp, PT_status32] ; get statu32_l2 (saved in pt_regs)
- bbit0 r9, STATUS_A1_BIT, 1f ; L1 not active when L2 IRQ, so normal
+ ld r9, [sp, PT_status32]
+ brne r9, 0, 1f
- ; A1 is set in status32_l2
- ; bump thread_info->preempt_count (Disable preemption)
- GET_CURR_THR_INFO_FROM_SP r10
- ld r9, [r10, THREAD_INFO_PREEMPT_COUNT]
- add r9, r9, 1
- st r9, [r10, THREAD_INFO_PREEMPT_COUNT]
+ jl.d [r14] ; kernel thread entry point
+ mov r0, r13 ; (see PF_KTHREAD block in copy_thread)
1:
- ;------------------------------------------------------
- ; setup params for Linux common ISR and invoke it
- ;------------------------------------------------------
- lr r0, [icause2]
- and r0, r0, 0x1f
-
- bl.d @arch_do_IRQ
- mov r1, sp
-
- mov r8,0x2
- sr r8, [AUX_IRQ_LV12] ; clear bit in Sticky Status Reg
-
- b ret_from_exception
-
-END(handle_interrupt_level2)
-
-#endif
-
-; ---------------------------------------------
-; Level 1 ISR
-; ---------------------------------------------
-ENTRY(handle_interrupt_level1)
-
- /* free up r9 as scratchpad */
-#ifdef CONFIG_SMP
- sr r9, [ARC_REG_SCRATCH_DATA0]
-#else
- st r9, [@int1_saved_reg]
-#endif
-
- ;Which mode (user/kernel) was the system in when intr occured
- lr r9, [status32_l1]
-
- SWITCH_TO_KERNEL_STK
- SAVE_ALL_INT1
+ ; Return to user space
+ ; 1. Any forked task (Reach here via BRne above)
+ ; 2. First ever init task (Reach here via return from JL above)
+ ; This is the historic "kernel_execve" use-case, to return to init
+ ; user mode, in a round about way since that is always done from
+ ; a kernel thread which is executed via JL above but always returns
+ ; out whenever kernel_execve (now inline do_fork()) is involved
+ b ret_from_exception
+END(ret_from_fork)
- lr r0, [icause1]
- and r0, r0, 0x1f
+#ifdef CONFIG_ARC_DW2_UNWIND
+; Workaround for bug 94179 (STAR ):
+; Despite -fasynchronous-unwind-tables, linker is not making dwarf2 unwinder
+; section (.debug_frame) as loadable. So we force it here.
+; This also fixes STAR 9000487933 where the prev-workaround (objcopy --setflag)
+; would not work after a clean build due to kernel build system dependencies.
+.section .debug_frame, "wa",@progbits
-#ifdef CONFIG_TRACE_IRQFLAGS
- ; icause1 needs to be read early, before calling tracing, which
- ; can clobber scratch regs, hence use of stack to stash it
- push r0
- TRACE_ASM_IRQ_DISABLE
- pop r0
+; Reset to .text as this file is included in entry-<isa>.S
+.section .text, "ax",@progbits
#endif
- bl.d @arch_do_IRQ
- mov r1, sp
-
- mov r8,0x1
- sr r8, [AUX_IRQ_LV12] ; clear bit in Sticky Status Reg
-
- b ret_from_exception
-END(handle_interrupt_level1)
-
;################### Non TLB Exception Handling #############################
; ---------------------------------------------
lr r0, [efa]
mov r1, sp
- FAKE_RET_FROM_EXCPN r9
+ FAKE_RET_FROM_EXCPN
bl do_insterror_or_kprobe
b ret_from_exception
END(instr_service)
-; ---------------------------------------------
-; Memory Error Exception Handler
-; ---------------------------------------------
-
-ENTRY(mem_service)
-
- EXCEPTION_PROLOGUE
-
- lr r0, [efa]
- mov r1, sp
-
- FAKE_RET_FROM_EXCPN r9
-
- bl do_memory_error
- b ret_from_exception
-END(mem_service)
-
; ---------------------------------------------
; Machine Check Exception Handler
; ---------------------------------------------
END(EV_MachineCheck)
-; ---------------------------------------------
-; Protection Violation Exception Handler
-; ---------------------------------------------
-
-ENTRY(EV_TLBProtV)
-
- EXCEPTION_PROLOGUE
-
- ;---------(3) Save some more regs-----------------
- ; vineetg: Mar 6th: Random Seg Fault issue #1
- ; ecr and efa were not saved in case an Intr sneaks in
- ; after fake rtie
-
- lr r2, [ecr]
- lr r0, [efa] ; Faulting Data address
-
- ; --------(4) Return from CPU Exception Mode ---------
- ; Fake a rtie, but rtie to next label
- ; That way, subsequently, do_page_fault ( ) executes in pure kernel
- ; mode with further Exceptions enabled
-
- FAKE_RET_FROM_EXCPN r9
-
- mov r1, sp
-
- ;------ (5) Type of Protection Violation? ----------
- ;
- ; ProtV Hardware Exception is triggered for Access Faults of 2 types
- ; -Access Violaton : 00_23_(00|01|02|03)_00
- ; x r w r+w
- ; -Unaligned Access : 00_23_04_00
- ;
- bbit1 r2, ECR_C_BIT_PROTV_MISALIG_DATA, 4f
-
- ;========= (6a) Access Violation Processing ========
- bl do_page_fault
- b ret_from_exception
-
- ;========== (6b) Non aligned access ============
-4:
-
- 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_TLBProtV)
-
; ---------------------------------------------
; Privilege Violation Exception Handler
; ---------------------------------------------
lr r0, [efa]
mov r1, sp
- FAKE_RET_FROM_EXCPN r9
+ FAKE_RET_FROM_EXCPN
bl do_privilege_fault
b ret_from_exception
lr r0, [efa]
mov r1, sp
- FAKE_RET_FROM_EXCPN r9
+ FAKE_RET_FROM_EXCPN
bl do_extension_fault
b ret_from_exception
END(EV_Extension)
-;######################### System Call Tracing #########################
+;################ Trap Handling (Syscall, Breakpoint) ##################
+; ---------------------------------------------
+; syscall Tracing
+; ---------------------------------------------
tracesys:
; save EFA in case tracer wants the PC of traced task
; using ERET won't work since next-PC has already committed
b ret_from_exception ; NOT ret_from_system_call at is saves r0 which
; we'd done before calling post hook above
-;################### Break Point TRAP ##########################
-
- ; ======= (5b) Trap is due to Break-Point =========
-
+; ---------------------------------------------
+; Breakpoint TRAP
+; ---------------------------------------------
trap_with_param:
; stop_pc info by gdb needs this info
; Now that we have read EFA, it is safe to do "fake" rtie
; and get out of CPU exception mode
- FAKE_RET_FROM_EXCPN r11
+ FAKE_RET_FROM_EXCPN
; Save callee regs in case gdb wants to have a look
; SP will grow up by size of CALLEE Reg-File
b ret_from_exception
-;##################### Trap Handling ##############################
-;
-; EV_Trap caused by TRAP_S and TRAP0 instructions.
-;------------------------------------------------------------------
-; (1) System Calls
-; :parameters in r0-r7.
-; :r8 has the system call number
-; (2) Break Points
-;------------------------------------------------------------------
+; ---------------------------------------------
+; syscall TRAP
+; ABI: (r0-r7) upto 8 args, (r8) syscall number
+; ---------------------------------------------
ENTRY(EV_Trap)
EXCEPTION_PROLOGUE
- ;------- (4) What caused the Trap --------------
- lr r12, [ecr]
- bmsk.f 0, r12, 7
+ ;============ TRAP 1 :breakpoints
+ ; Check ECR for trap with arg (PROLOGUE ensures r9 has ECR)
+ bmsk.f 0, r9, 7
bnz trap_with_param
- ; ======= (5a) Trap is due to System Call ========
+ ;============ TRAP (no param): syscall top level
- ; Before doing anything, return from CPU Exception Mode
- FAKE_RET_FROM_EXCPN r11
+ ; First return from Exception to pure K mode (Exception/IRQs renabled)
+ FAKE_RET_FROM_EXCPN
- ; If syscall tracing ongoing, invoke pre-pos-hooks
+ ; If syscall tracing ongoing, invoke pre-post-hooks
GET_CURR_THR_INFO_FLAGS r10
btst r10, TIF_SYSCALL_TRACE
bnz tracesys ; this never comes back
- ;============ This is normal System Call case ==========
- ; Sys-call num shd not exceed the total system calls avail
+ ;============ Normal syscall case
+
+ ; syscall num shd not exceed the total system calls avail
cmp r8, NR_syscalls
mov.hi r0, -ENOSYS
bhi ret_from_system_call
; Fast Path return to user mode if no pending work
GET_CURR_THR_INFO_FLAGS r9
and.f 0, r9, _TIF_WORK_MASK
- bz restore_regs
+ bz .Lrestore_regs
; --- (Slow Path #1) task preemption ---
bbit0 r9, TIF_NEED_RESCHED, .Lchk_pend_signals
mov blink, resume_user_mode_begin ; tail-call to U mode ret chks
- b @schedule ; BTST+Bnz causes relo error in link
+ j @schedule ; BTST+Bnz causes relo error in link
.Lchk_pend_signals:
IRQ_ENABLE r10
; Can't preempt if preemption disabled
GET_CURR_THR_INFO_FROM_SP r10
ld r8, [r10, THREAD_INFO_PREEMPT_COUNT]
- brne r8, 0, restore_regs
+ brne r8, 0, .Lrestore_regs
; check if this task's NEED_RESCHED flag set
ld r9, [r10, THREAD_INFO_FLAGS]
- bbit0 r9, TIF_NEED_RESCHED, restore_regs
+ bbit0 r9, TIF_NEED_RESCHED, .Lrestore_regs
; Invoke PREEMPTION
- bl preempt_schedule_irq
+ jl preempt_schedule_irq
; preempt_schedule_irq() always returns with IRQ disabled
#endif
- ; fall through
-
-;############# Return from Intr/Excp/Trap (ARC 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
-
-restore_regs :
-
- TRACE_ASM_IRQ_ENABLE
-
- lr r10, [status32]
-
- ; Restore REG File. In case multiple Events outstanding,
- ; use the same priorty as rtie: EXCPN, L2 IRQ, L1 IRQ, None
- ; Note that we use realtime STATUS32 (not pt_regs->status32) to
- ; decide that.
-
- ; if Returning from Exception
- bbit0 r10, STATUS_AE_BIT, not_exception
- RESTORE_ALL_SYS
- rtie
-
- ; Not Exception so maybe Interrupts (Level 1 or 2)
+ b .Lrestore_regs
-not_exception:
+##### DONT ADD CODE HERE - .Lrestore_regs actually follows in entry-<isa>.S
-#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS
-
- ; Level 2 interrupt return Path - from hardware standpoint
- bbit0 r10, STATUS_A2_BIT, not_level2_interrupt
-
- ;------------------------------------------------------------------
- ; However the context returning might not have taken L2 intr itself
- ; e.g. Task'A' user-code -> L2 intr -> schedule -> 'B' user-code ret
- ; Special considerations needed for the context which took L2 intr
-
- ld r9, [sp, PT_event] ; Ensure this is L2 intr context
- brne r9, event_IRQ2, 149f
-
- ;------------------------------------------------------------------
- ; if L2 IRQ interrupted an L1 ISR, we'd disabled preemption earlier
- ; so that sched doesn't move to new task, causing L1 to be delayed
- ; undeterministically. Now that we've achieved that, let's reset
- ; things to what they were, before returning from L2 context
- ;----------------------------------------------------------------
-
- ld r9, [sp, PT_status32] ; get statu32_l2 (saved in pt_regs)
- bbit0 r9, STATUS_A1_BIT, 149f ; L1 not active when L2 IRQ, so normal
-
- ; decrement thread_info->preempt_count (re-enable preemption)
- GET_CURR_THR_INFO_FROM_SP r10
- ld r9, [r10, THREAD_INFO_PREEMPT_COUNT]
-
- ; paranoid check, given A1 was active when A2 happened, preempt count
- ; must not be 0 because we would have incremented it.
- ; If this does happen we simply HALT as it means a BUG !!!
- cmp r9, 0
- bnz 2f
- flag 1
-
-2:
- sub r9, r9, 1
- st r9, [r10, THREAD_INFO_PREEMPT_COUNT]
-
-149:
- ;return from level 2
- RESTORE_ALL_INT2
-debug_marker_l2:
- rtie
-
-not_level2_interrupt:
-
-#endif
-
- bbit0 r10, STATUS_A1_BIT, not_level1_interrupt
-
- ;return from level 1
-
- RESTORE_ALL_INT1
-debug_marker_l1:
- rtie
-
-not_level1_interrupt:
-
- ;this case is for syscalls or Exceptions (with fake rtie)
-
- RESTORE_ALL_SYS
-debug_marker_syscall:
- rtie
-
-END(ret_from_exception)
-
-ENTRY(ret_from_fork)
- ; when the forked child comes here from the __switch_to function
- ; r0 has the last task pointer.
- ; put last task in scheduler queue
- bl @schedule_tail
-
- ld r9, [sp, PT_status32]
- brne r9, 0, 1f
-
- jl.d [r14] ; kernel thread entry point
- mov r0, r13 ; (see PF_KTHREAD block in copy_thread)
-
-1:
- ; Return to user space
- ; 1. Any forked task (Reach here via BRne above)
- ; 2. First ever init task (Reach here via return from JL above)
- ; This is the historic "kernel_execve" use-case, to return to init
- ; user mode, in a round about way since that is always done from
- ; a kernel thread which is executed via JL above but always returns
- ; out whenever kernel_execve (now inline do_fork()) is involved
- b ret_from_exception
-END(ret_from_fork)
-
-;################### Special Sys Call Wrappers ##########################
-
-ENTRY(sys_clone_wrapper)
- SAVE_CALLEE_SAVED_USER
- bl @sys_clone
- DISCARD_CALLEE_SAVED_USER
-
- GET_CURR_THR_INFO_FLAGS r10
- btst r10, TIF_SYSCALL_TRACE
- bnz tracesys_exit
-
- b ret_from_system_call
-END(sys_clone_wrapper)
-
-#ifdef CONFIG_ARC_DW2_UNWIND
-; Workaround for bug 94179 (STAR ):
-; Despite -fasynchronous-unwind-tables, linker is not making dwarf2 unwinder
-; section (.debug_frame) as loadable. So we force it here.
-; This also fixes STAR 9000487933 where the prev-workaround (objcopy --setflag)
-; would not work after a clean build due to kernel build system dependencies.
-.section .debug_frame, "wa",@progbits
-#endif
Code Review / kvmfornfv.git / blobdiff