ARC: entry.S: split into ARCompact ISA specific, common bits

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

1 files changed, 7 insertions, 382 deletions

diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S
index 286d7dc0723b..75cdc56351d9 100644
--- a/arch/arc/kernel/entry.S
+++ b/arch/arc/kernel/entry.S
@@ -1,60 +1,13 @@
 /*
- * 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
  */
 
 /*------------------------------------------------------------------
@@ -67,187 +20,10 @@
  *  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)
-
-	INTERRUPT_PROLOGUE 2
-
-	;------------------------------------------------------
-	; if L2 IRQ interrupted a L1 ISR, disable preemption
-	;------------------------------------------------------
-
-	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
-
-	; 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]
-
-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)
-
-	INTERRUPT_PROLOGUE 1
-
-	lr  r0, [icause1]
-	and r0, r0, 0x1f
-
-#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
-#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 #############################
 
 ; ---------------------------------------------
@@ -315,70 +91,6 @@ ENTRY(EV_MachineCheck)
 END(EV_MachineCheck)
 
 ; ---------------------------------------------
-; Protection Violation Exception Handler
-; ---------------------------------------------
-
-ENTRY(EV_TLBProtV)
-
-	EXCEPTION_PROLOGUE
-
-	lr  r2, [ecr]
-	lr  r0, [efa]	; Faulting Data addr (not part of pt_regs saved above)
-
-	; Exception auto-disables further Intr/exceptions.
-	; Re-enable them by pretending to return from exception
-	; (so rest of handler executes in pure K mode)
-
-	FAKE_RET_FROM_EXCPN
-
-	mov   r1, sp	; Handle to pt_regs
-
-	;------ (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)
-
-; Wrapper for Linux page fault handler called from EV_TLBMiss*
-; Very similar to ProtV handler case (6a) above, but avoids the extra checks
-; for Misaligned access
-;
-ENTRY(call_do_page_fault)
-
-	EXCEPTION_PROLOGUE
-	lr  r0, [efa]	; Faulting Data address
-	mov   r1, sp
-	FAKE_RET_FROM_EXCPN
-
-	mov blink, ret_from_exception
-	b  do_page_fault
-
-END(call_do_page_fault)
-
-; ---------------------------------------------
 ; Privilege Violation Exception Handler
 ; ---------------------------------------------
 ENTRY(EV_PrivilegeV)
@@ -625,97 +337,7 @@ resume_kernel_mode:
 	; 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
-
-.Lrestore_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
-	EXCEPTION_EPILOGUE
-	rtie
-
-	; Not Exception so maybe Interrupts (Level 1 or 2)
-
-not_exception:
-
-#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
-	INTERRUPT_EPILOGUE 2
-debug_marker_l2:
-	rtie
-
-not_level2_interrupt:
-
-#endif
-
-	bbit0  r10, STATUS_A1_BIT, not_level1_interrupt
-
-	;return from level 1
-	INTERRUPT_EPILOGUE 1
-debug_marker_l1:
-	rtie
-
-not_level1_interrupt:
-
-	;this case is for syscalls or Exceptions (with fake rtie)
-
-	EXCEPTION_EPILOGUE
-debug_marker_syscall:
-	rtie
-
+	b	.Lrestore_regs
 END(ret_from_exception)
 
 ENTRY(ret_from_fork)
@@ -762,4 +384,7 @@ END(sys_clone_wrapper)
 ; 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
+
+; Reset to .text as this file is included in entry-<isa>.S
+.section .text, "ax",@progbits
 #endif