arch/arc/include/asm/entry.h - linux - Git at Google

 /*
  * 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: March 2009 (Supporting 2 levels of Interrupts)
  *  Stack switching code can no longer reliably rely on the fact that
  *  if we are NOT in user mode, stack is switched to kernel mode.
  *  e.g. L2 IRQ interrupted a L1 ISR which had not yet completed
  *  it's prologue including stack switching from user mode
  *
  * 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 also 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". Actually "SET" clears ZOL context
  *
  * Vineetg: May 5th 2008
  *  -Modified CALLEE_REG save/restore macros to handle the fact that
  *      r25 contains the kernel current task ptr
  *  - Defined Stack Switching Macro to be reused in all intr/excp hdlrs
  *  - Shaved off 11 instructions from RESTORE_ALL_INT1 by using the
  *      address Write back load ld.ab instead of seperate ld/add instn
  *
  * Amit Bhor, Sameer Dhavale: Codito Technologies 2004
  */

 #ifndef __ASM_ARC_ENTRY_H
 #define __ASM_ARC_ENTRY_H

 #ifdef __ASSEMBLY__
 #include <asm/unistd.h>		/* For NR_syscalls defination */
 #include <asm/asm-offsets.h>
 #include <asm/arcregs.h>
 #include <asm/ptrace.h>
 #include <asm/processor.h>	/* For VMALLOC_START */
 #include <asm/thread_info.h>	/* For THREAD_SIZE */

 /* Note on the LD/ST addr modes with addr reg wback
  *
  * LD.a same as LD.aw
  *
  * LD.a    reg1, [reg2, x]  => Pre Incr
  *      Eff Addr for load = [reg2 + x]
  *
  * LD.ab   reg1, [reg2, x]  => Post Incr
  *      Eff Addr for load = [reg2]
  */

 /*--------------------------------------------------------------
  * Save caller saved registers (scratch registers) ( r0 - r12 )
  * Registers are pushed / popped in the order defined in struct ptregs
  * in asm/ptrace.h
  *-------------------------------------------------------------*/
 .macro  SAVE_CALLER_SAVED
 	st.a    r0, [sp, -4]
 	st.a    r1, [sp, -4]
 	st.a    r2, [sp, -4]
 	st.a    r3, [sp, -4]
 	st.a    r4, [sp, -4]
 	st.a    r5, [sp, -4]
 	st.a    r6, [sp, -4]
 	st.a    r7, [sp, -4]
 	st.a    r8, [sp, -4]
 	st.a    r9, [sp, -4]
 	st.a    r10, [sp, -4]
 	st.a    r11, [sp, -4]
 	st.a    r12, [sp, -4]
 .endm

 /*--------------------------------------------------------------
  * Restore caller saved registers (scratch registers)
  *-------------------------------------------------------------*/
 .macro RESTORE_CALLER_SAVED
 	ld.ab   r12, [sp, 4]
 	ld.ab   r11, [sp, 4]
 	ld.ab   r10, [sp, 4]
 	ld.ab   r9, [sp, 4]
 	ld.ab   r8, [sp, 4]
 	ld.ab   r7, [sp, 4]
 	ld.ab   r6, [sp, 4]
 	ld.ab   r5, [sp, 4]
 	ld.ab   r4, [sp, 4]
 	ld.ab   r3, [sp, 4]
 	ld.ab   r2, [sp, 4]
 	ld.ab   r1, [sp, 4]
 	ld.ab   r0, [sp, 4]
 .endm


 /*--------------------------------------------------------------
  * Save callee saved registers (non scratch registers) ( r13 - r25 )
  *  on kernel stack.
  * User mode callee regs need to be saved in case of
  *    -fork and friends for replicating from parent to child
  *    -before going into do_signal( ) for ptrace/core-dump
  * Special case handling is required for r25 in case it is used by kernel
  *  for caching task ptr. Low level exception/ISR save user mode r25
  *  into task->thread.user_r25. So it needs to be retrieved from there and
  *  saved into kernel stack with rest of callee reg-file
  *-------------------------------------------------------------*/
 .macro SAVE_CALLEE_SAVED_USER
 	st.a    r13, [sp, -4]
 	st.a    r14, [sp, -4]
 	st.a    r15, [sp, -4]
 	st.a    r16, [sp, -4]
 	st.a    r17, [sp, -4]
 	st.a    r18, [sp, -4]
 	st.a    r19, [sp, -4]
 	st.a    r20, [sp, -4]
 	st.a    r21, [sp, -4]
 	st.a    r22, [sp, -4]
 	st.a    r23, [sp, -4]
 	st.a    r24, [sp, -4]

 #ifdef CONFIG_ARC_CURR_IN_REG
 	; Retrieve orig r25 and save it on stack
 	ld      r12, [r25, TASK_THREAD + THREAD_USER_R25]
 	st.a    r12, [sp, -4]
 #else
 	st.a    r25, [sp, -4]
 #endif

 	/* move up by 1 word to "create" callee_regs->"stack_place_holder" */
 	sub sp, sp, 4
 .endm

 /*--------------------------------------------------------------
  * Save callee saved registers (non scratch registers) ( r13 - r25 )
  * kernel mode callee regs needed to be saved in case of context switch
  * If r25 is used for caching task pointer then that need not be saved
  * as it can be re-created from current task global
  *-------------------------------------------------------------*/
 .macro SAVE_CALLEE_SAVED_KERNEL
 	st.a    r13, [sp, -4]
 	st.a    r14, [sp, -4]
 	st.a    r15, [sp, -4]
 	st.a    r16, [sp, -4]
 	st.a    r17, [sp, -4]
 	st.a    r18, [sp, -4]
 	st.a    r19, [sp, -4]
 	st.a    r20, [sp, -4]
 	st.a    r21, [sp, -4]
 	st.a    r22, [sp, -4]
 	st.a    r23, [sp, -4]
 	st.a    r24, [sp, -4]
 #ifdef CONFIG_ARC_CURR_IN_REG
 	sub     sp, sp, 8
 #else
 	st.a    r25, [sp, -4]
 	sub     sp, sp, 4
 #endif
 .endm

 /*--------------------------------------------------------------
  * RESTORE_CALLEE_SAVED_KERNEL:
  * Loads callee (non scratch) Reg File by popping from Kernel mode stack.
  *  This is reverse of SAVE_CALLEE_SAVED,
  *
  * NOTE:
  * Ideally this shd only be called in switch_to for loading
  *  switched-IN task's CALLEE Reg File.
  *  For all other cases RESTORE_CALLEE_SAVED_FAST must be used
  *  which simply pops the stack w/o touching regs.
  *-------------------------------------------------------------*/
 .macro RESTORE_CALLEE_SAVED_KERNEL


 #ifdef CONFIG_ARC_CURR_IN_REG
 	add     sp, sp, 8  /* skip callee_reg gutter and user r25 placeholder */
 #else
 	add     sp, sp, 4   /* skip "callee_regs->stack_place_holder" */
 	ld.ab   r25, [sp, 4]
 #endif

 	ld.ab   r24, [sp, 4]
 	ld.ab   r23, [sp, 4]
 	ld.ab   r22, [sp, 4]
 	ld.ab   r21, [sp, 4]
 	ld.ab   r20, [sp, 4]
 	ld.ab   r19, [sp, 4]
 	ld.ab   r18, [sp, 4]
 	ld.ab   r17, [sp, 4]
 	ld.ab   r16, [sp, 4]
 	ld.ab   r15, [sp, 4]
 	ld.ab   r14, [sp, 4]
 	ld.ab   r13, [sp, 4]

 .endm

 /*--------------------------------------------------------------
  * RESTORE_CALLEE_SAVED_USER:
  * This is called after do_signal where tracer might have changed callee regs
  * thus we need to restore the reg file.
  * Special case handling is required for r25 in case it is used by kernel
  *  for caching task ptr. Ptrace would have modified on-kernel-stack value of
  *  r25, which needs to be shoved back into task->thread.user_r25 where from
  *  Low level exception/ISR return code will retrieve to populate with rest of
  *  callee reg-file.
  *-------------------------------------------------------------*/
 .macro RESTORE_CALLEE_SAVED_USER

 	add     sp, sp, 4   /* skip "callee_regs->stack_place_holder" */

 #ifdef CONFIG_ARC_CURR_IN_REG
 	ld.ab   r12, [sp, 4]
 	st      r12, [r25, TASK_THREAD + THREAD_USER_R25]
 #else
 	ld.ab   r25, [sp, 4]
 #endif

 	ld.ab   r24, [sp, 4]
 	ld.ab   r23, [sp, 4]
 	ld.ab   r22, [sp, 4]
 	ld.ab   r21, [sp, 4]
 	ld.ab   r20, [sp, 4]
 	ld.ab   r19, [sp, 4]
 	ld.ab   r18, [sp, 4]
 	ld.ab   r17, [sp, 4]
 	ld.ab   r16, [sp, 4]
 	ld.ab   r15, [sp, 4]
 	ld.ab   r14, [sp, 4]
 	ld.ab   r13, [sp, 4]
 .endm

 /*--------------------------------------------------------------
  * Super FAST Restore callee saved regs by simply re-adjusting SP
  *-------------------------------------------------------------*/
 .macro DISCARD_CALLEE_SAVED_USER
 	add     sp, sp, 14 * 4
 .endm

 /*--------------------------------------------------------------
  * Restore User mode r25 saved in task_struct->thread.user_r25
  *-------------------------------------------------------------*/
 .macro RESTORE_USER_R25
 	ld  r25, [r25, TASK_THREAD + THREAD_USER_R25]
 .endm

 /*-------------------------------------------------------------
  * given a tsk struct, get to the base of it's kernel mode stack
  * tsk->thread_info is really a PAGE, whose bottom hoists stack
  * which grows upwards towards thread_info
  *------------------------------------------------------------*/

 .macro GET_TSK_STACK_BASE tsk, out

 	/* Get task->thread_info (this is essentially start of a PAGE) */
 	ld  \out, [\tsk, TASK_THREAD_INFO]

 	/* Go to end of page where stack begins (grows upwards) */
 	add2 \out, \out, (THREAD_SIZE - 4)/4   /* one word GUTTER */

 .endm

 /*--------------------------------------------------------------
  * Switch to Kernel Mode stack if SP points to User Mode stack
  *
  * Entry   : r9 contains pre-IRQ/exception/trap status32
  * Exit    : SP is set to kernel mode stack pointer
  *           If CURR_IN_REG, r25 set to "current" task pointer
  * Clobbers: r9
  *-------------------------------------------------------------*/

 .macro SWITCH_TO_KERNEL_STK

 	/* User Mode when this happened ? Yes: Proceed to switch stack */
 	bbit1   r9, STATUS_U_BIT, 88f

 	/* OK we were already in kernel mode when this event happened, thus can
 	 * assume SP is kernel mode SP. _NO_ need to do any stack switching
 	 */

 #ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS
 	/* However....
 	 * If Level 2 Interrupts enabled, we may end up with a corner case:
 	 * 1. User Task executing
 	 * 2. L1 IRQ taken, ISR starts (CPU auto-switched to KERNEL mode)
 	 * 3. But before it could switch SP from USER to KERNEL stack
 	 *      a L2 IRQ "Interrupts" L1
 	 * Thay way although L2 IRQ happened in Kernel mode, stack is still
 	 * not switched.
 	 * To handle this, we may need to switch stack even if in kernel mode
 	 * provided SP has values in range of USER mode stack ( < 0x7000_0000 )
 	 */
 	brlo sp, VMALLOC_START, 88f

 	/* TODO: vineetg:
 	 * We need to be a bit more cautious here. What if a kernel bug in
 	 * L1 ISR, caused SP to go whaco (some small value which looks like
 	 * USER stk) and then we take L2 ISR.
 	 * Above brlo alone would treat it as a valid L1-L2 sceanrio
 	 * instead of shouting alound
 	 * The only feasible way is to make sure this L2 happened in
 	 * L1 prelogue ONLY i.e. ilink2 is less than a pre-set marker in
 	 * L1 ISR before it switches stack
 	 */

 #endif

 	/* Save Pre Intr/Exception KERNEL MODE SP on kernel stack
 	 * safe-keeping not really needed, but it keeps the epilogue code
 	 * (SP restore) simpler/uniform.
 	 */
 	b.d	77f

 	st.a	sp, [sp, -12]	; Make room for orig_r0 and orig_r8

 88: /*------Intr/Ecxp happened in user mode, "switch" stack ------ */

 	GET_CURR_TASK_ON_CPU   r9

 #ifdef CONFIG_ARC_CURR_IN_REG

 	/* If current task pointer cached in r25, time to
 	 *  -safekeep USER r25 in task->thread_struct->user_r25
 	 *  -load r25 with current task ptr
 	 */
 	st.as	r25, [r9, (TASK_THREAD + THREAD_USER_R25)/4]
 	mov	r25, r9
 #endif

 	/* With current tsk in r9, get it's kernel mode stack base */
 	GET_TSK_STACK_BASE  r9, r9

 #ifdef PT_REGS_CANARY
 	st	0xabcdabcd, [r9, 0]
 #endif

 	/* Save Pre Intr/Exception User SP on kernel stack */
 	st.a    sp, [r9, -12]	; Make room for orig_r0 and orig_r8

 	/* CAUTION:
 	 * SP should be set at the very end when we are done with everything
 	 * In case of 2 levels of interrupt we depend on value of SP to assume
 	 * that everything else is done (loading r25 etc)
 	 */

 	/* set SP to point to kernel mode stack */
 	mov sp, r9

 77: /* ----- Stack Switched to kernel Mode, Now save REG FILE ----- */

 .endm

 /*------------------------------------------------------------
  * "FAKE" a rtie to return from CPU Exception context
  * This is to re-enable Exceptions within exception
  * Look at EV_ProtV to see how this is actually used
  *-------------------------------------------------------------*/

 .macro FAKE_RET_FROM_EXCPN  reg

 	ld  \reg, [sp, PT_status32]
 	bic  \reg, \reg, (STATUS_U_MASK|STATUS_DE_MASK)
 	bset \reg, \reg, STATUS_L_BIT
 	sr  \reg, [erstatus]
 	mov \reg, 55f
 	sr  \reg, [eret]

 	rtie
 55:
 .endm

 /*
  * @reg [OUT] &thread_info of "current"
  */
 .macro GET_CURR_THR_INFO_FROM_SP  reg
 	and \reg, sp, ~(THREAD_SIZE - 1)
 .endm

 /*
  * @reg [OUT] thread_info->flags of "current"
  */
 .macro GET_CURR_THR_INFO_FLAGS  reg
 	GET_CURR_THR_INFO_FROM_SP  \reg
 	ld  \reg, [\reg, THREAD_INFO_FLAGS]
 .endm

 /*--------------------------------------------------------------
  * For early Exception Prologue, a core reg is temporarily needed to
  * code the rest of prolog (stack switching). This is done by stashing
  * it to memory (non-SMP case) or SCRATCH0 Aux Reg (SMP).
  *
  * Before saving the full regfile - this reg is restored back, only
  * to be saved again on kernel mode stack, as part of ptregs.
  *-------------------------------------------------------------*/
 .macro EXCPN_PROLOG_FREEUP_REG	reg
 #ifdef CONFIG_SMP
 	sr  \reg, [ARC_REG_SCRATCH_DATA0]
 #else
 	st  \reg, [@ex_saved_reg1]
 #endif
 .endm

 .macro EXCPN_PROLOG_RESTORE_REG	reg
 #ifdef CONFIG_SMP
 	lr  \reg, [ARC_REG_SCRATCH_DATA0]
 #else
 	ld  \reg, [@ex_saved_reg1]
 #endif
 .endm

 /*--------------------------------------------------------------
  * Save all registers used by Exceptions (TLB Miss, Prot-V, Mem err etc)
  * Requires SP to be already switched to kernel mode Stack
  * sp points to the next free element on the stack at exit of this macro.
  * Registers are pushed / popped in the order defined in struct ptregs
  * in asm/ptrace.h
  * Note that syscalls are implemented via TRAP which is also a exception
  * from CPU's point of view
  *-------------------------------------------------------------*/
 .macro SAVE_ALL_EXCEPTION   marker

 	st      \marker, [sp, 8]	/* orig_r8 */
 	st      r0, [sp, 4]    /* orig_r0, needed only for sys calls */

 	/* Restore r9 used to code the early prologue */
 	EXCPN_PROLOG_RESTORE_REG  r9

 	SAVE_CALLER_SAVED
 	st.a    r26, [sp, -4]   /* gp */
 	st.a    fp, [sp, -4]
 	st.a    blink, [sp, -4]
 	lr	r9, [eret]
 	st.a    r9, [sp, -4]
 	lr	r9, [erstatus]
 	st.a    r9, [sp, -4]
 	st.a    lp_count, [sp, -4]
 	lr	r9, [lp_end]
 	st.a    r9, [sp, -4]
 	lr	r9, [lp_start]
 	st.a    r9, [sp, -4]
 	lr	r9, [erbta]
 	st.a    r9, [sp, -4]

 #ifdef PT_REGS_CANARY
 	mov   r9, 0xdeadbeef
 	st    r9, [sp, -4]
 #endif

 	/* move up by 1 word to "create" pt_regs->"stack_place_holder" */
 	sub sp, sp, 4
 .endm

 /*--------------------------------------------------------------
  * Save scratch regs for exceptions
  *-------------------------------------------------------------*/
 .macro SAVE_ALL_SYS
 	SAVE_ALL_EXCEPTION  orig_r8_IS_EXCPN
 .endm

 /*--------------------------------------------------------------
  * Save scratch regs for sys calls
  *-------------------------------------------------------------*/
 .macro SAVE_ALL_TRAP
 	/*
 	 * Setup pt_regs->orig_r8.
 	 * Encode syscall number (r8) in upper short word of event type (r9)
 	 * N.B. #1: This is already endian safe (see ptrace.h)
 	 *      #2: Only r9 can be used as scratch as it is already clobbered
 	 *          and it's contents are no longer needed by the latter part
 	 *          of exception prologue
 	 */
 	lsl  r9, r8, 16
 	or   r9, r9, orig_r8_IS_SCALL

 	SAVE_ALL_EXCEPTION  r9
 .endm

 /*--------------------------------------------------------------
  * Restore all registers used by system call or Exceptions
  * SP should always be pointing to the next free stack element
  * when entering this macro.
  *
  * NOTE:
  *
  * It is recommended that lp_count/ilink1/ilink2 not be used as a dest reg
  * for memory load operations. If used in that way interrupts are deffered
  * by hardware and that is not good.
  *-------------------------------------------------------------*/
 .macro RESTORE_ALL_SYS

 	add sp, sp, 4       /* hop over unused "pt_regs->stack_place_holder" */

 	ld.ab   r9, [sp, 4]
 	sr	r9, [erbta]
 	ld.ab   r9, [sp, 4]
 	sr	r9, [lp_start]
 	ld.ab   r9, [sp, 4]
 	sr	r9, [lp_end]
 	ld.ab   r9, [sp, 4]
 	mov	lp_count, r9
 	ld.ab   r9, [sp, 4]
 	sr	r9, [erstatus]
 	ld.ab   r9, [sp, 4]
 	sr	r9, [eret]
 	ld.ab   blink, [sp, 4]
 	ld.ab   fp, [sp, 4]
 	ld.ab   r26, [sp, 4]    /* gp */
 	RESTORE_CALLER_SAVED

 	ld  sp, [sp] /* restore original sp */
 	/* orig_r0 and orig_r8 skipped automatically */
 .endm


 /*--------------------------------------------------------------
  * Save all registers used by interrupt handlers.
  *-------------------------------------------------------------*/
 .macro SAVE_ALL_INT1

 	/* restore original r9 , saved in int1_saved_reg
 	* It will be saved on stack in macro: SAVE_CALLER_SAVED
 	*/
 #ifdef CONFIG_SMP
 	lr  r9, [ARC_REG_SCRATCH_DATA0]
 #else
 	ld  r9, [@int1_saved_reg]
 #endif

 	/* now we are ready to save the remaining context :) */
 	st      orig_r8_IS_IRQ1, [sp, 8]    /* Event Type */
 	st      0, [sp, 4]    /* orig_r0 , N/A for IRQ */
 	SAVE_CALLER_SAVED
 	st.a    r26, [sp, -4]   /* gp */
 	st.a    fp, [sp, -4]
 	st.a    blink, [sp, -4]
 	st.a    ilink1, [sp, -4]
 	lr	r9, [status32_l1]
 	st.a    r9, [sp, -4]
 	st.a    lp_count, [sp, -4]
 	lr	r9, [lp_end]
 	st.a    r9, [sp, -4]
 	lr	r9, [lp_start]
 	st.a    r9, [sp, -4]
 	lr	r9, [bta_l1]
 	st.a    r9, [sp, -4]

 #ifdef PT_REGS_CANARY
 	mov   r9, 0xdeadbee1
 	st    r9, [sp, -4]
 #endif
 	/* move up by 1 word to "create" pt_regs->"stack_place_holder" */
 	sub sp, sp, 4
 .endm

 .macro SAVE_ALL_INT2

 	/* TODO-vineetg: SMP we can't use global nor can we use
 	*   SCRATCH0 as we do for int1 because while int1 is using
 	*   it, int2 can come
 	*/
 	/* retsore original r9 , saved in sys_saved_r9 */
 	ld  r9, [@int2_saved_reg]

 	/* now we are ready to save the remaining context :) */
 	st      orig_r8_IS_IRQ2, [sp, 8]    /* Event Type */
 	st      0, [sp, 4]    /* orig_r0 , N/A for IRQ */
 	SAVE_CALLER_SAVED
 	st.a    r26, [sp, -4]   /* gp */
 	st.a    fp, [sp, -4]
 	st.a    blink, [sp, -4]
 	st.a    ilink2, [sp, -4]
 	lr	r9, [status32_l2]
 	st.a    r9, [sp, -4]
 	st.a    lp_count, [sp, -4]
 	lr	r9, [lp_end]
 	st.a    r9, [sp, -4]
 	lr	r9, [lp_start]
 	st.a    r9, [sp, -4]
 	lr	r9, [bta_l2]
 	st.a    r9, [sp, -4]

 #ifdef PT_REGS_CANARY
 	mov   r9, 0xdeadbee2
 	st    r9, [sp, -4]
 #endif

 	/* move up by 1 word to "create" pt_regs->"stack_place_holder" */
 	sub sp, sp, 4
 .endm

 /*--------------------------------------------------------------
  * Restore all registers used by interrupt handlers.
  *
  * NOTE:
  *
  * It is recommended that lp_count/ilink1/ilink2 not be used as a dest reg
  * for memory load operations. If used in that way interrupts are deffered
  * by hardware and that is not good.
  *-------------------------------------------------------------*/

 .macro RESTORE_ALL_INT1
 	add sp, sp, 4       /* hop over unused "pt_regs->stack_place_holder" */

 	ld.ab   r9, [sp, 4] /* Actual reg file */
 	sr	r9, [bta_l1]
 	ld.ab   r9, [sp, 4]
 	sr	r9, [lp_start]
 	ld.ab   r9, [sp, 4]
 	sr	r9, [lp_end]
 	ld.ab   r9, [sp, 4]
 	mov	lp_count, r9
 	ld.ab   r9, [sp, 4]
 	sr	r9, [status32_l1]
 	ld.ab   r9, [sp, 4]
 	mov	ilink1, r9
 	ld.ab   blink, [sp, 4]
 	ld.ab   fp, [sp, 4]
 	ld.ab   r26, [sp, 4]    /* gp */
 	RESTORE_CALLER_SAVED

 	ld  sp, [sp] /* restore original sp */
 	/* orig_r0 and orig_r8 skipped automatically */
 .endm

 .macro RESTORE_ALL_INT2
 	add sp, sp, 4       /* hop over unused "pt_regs->stack_place_holder" */

 	ld.ab   r9, [sp, 4]
 	sr	r9, [bta_l2]
 	ld.ab   r9, [sp, 4]
 	sr	r9, [lp_start]
 	ld.ab   r9, [sp, 4]
 	sr	r9, [lp_end]
 	ld.ab   r9, [sp, 4]
 	mov	lp_count, r9
 	ld.ab   r9, [sp, 4]
 	sr	r9, [status32_l2]
 	ld.ab   r9, [sp, 4]
 	mov	ilink2, r9
 	ld.ab   blink, [sp, 4]
 	ld.ab   fp, [sp, 4]
 	ld.ab   r26, [sp, 4]    /* gp */
 	RESTORE_CALLER_SAVED

 	ld  sp, [sp] /* restore original sp */
 	/* orig_r0 and orig_r8 skipped automatically */

 .endm


 /* Get CPU-ID of this core */
 .macro  GET_CPU_ID  reg
 	lr  \reg, [identity]
 	lsr \reg, \reg, 8
 	bmsk \reg, \reg, 7
 .endm

 #ifdef CONFIG_SMP

 /*-------------------------------------------------
  * Retrieve the current running task on this CPU
  * 1. Determine curr CPU id.
  * 2. Use it to index into _current_task[ ]
  */
 .macro  GET_CURR_TASK_ON_CPU   reg
 	GET_CPU_ID  \reg
 	ld.as  \reg, [@_current_task, \reg]
 .endm

 /*-------------------------------------------------
  * Save a new task as the "current" task on this CPU
  * 1. Determine curr CPU id.
  * 2. Use it to index into _current_task[ ]
  *
  * Coded differently than GET_CURR_TASK_ON_CPU (which uses LD.AS)
  * because ST r0, [r1, offset] can ONLY have s9 @offset
  * while   LD can take s9 (4 byte insn) or LIMM (8 byte insn)
  */

 .macro  SET_CURR_TASK_ON_CPU    tsk, tmp
 	GET_CPU_ID  \tmp
 	add2 \tmp, @_current_task, \tmp
 	st   \tsk, [\tmp]
 #ifdef CONFIG_ARC_CURR_IN_REG
 	mov r25, \tsk
 #endif

 .endm


 #else   /* Uniprocessor implementation of macros */

 .macro  GET_CURR_TASK_ON_CPU    reg
 	ld  \reg, [@_current_task]
 .endm

 .macro  SET_CURR_TASK_ON_CPU    tsk, tmp
 	st  \tsk, [@_current_task]
 #ifdef CONFIG_ARC_CURR_IN_REG
 	mov r25, \tsk
 #endif
 .endm

 #endif /* SMP / UNI */

 /* ------------------------------------------------------------------
  * Get the ptr to some field of Current Task at @off in task struct
  *  -Uses r25 for Current task ptr if that is enabled
  */

 #ifdef CONFIG_ARC_CURR_IN_REG

 .macro GET_CURR_TASK_FIELD_PTR  off,  reg
 	add \reg, r25, \off
 .endm

 #else

 .macro GET_CURR_TASK_FIELD_PTR  off,  reg
 	GET_CURR_TASK_ON_CPU  \reg
 	add \reg, \reg, \off
 .endm

 #endif	/* CONFIG_ARC_CURR_IN_REG */

 #endif  /* __ASSEMBLY__ */

 #endif  /* __ASM_ARC_ENTRY_H */
	/*
	* 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: March 2009 (Supporting 2 levels of Interrupts)
	* Stack switching code can no longer reliably rely on the fact that
	* if we are NOT in user mode, stack is switched to kernel mode.
	* e.g. L2 IRQ interrupted a L1 ISR which had not yet completed
	* it's prologue including stack switching from user mode
	*
	* 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 also 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". Actually "SET" clears ZOL context
	*
	* Vineetg: May 5th 2008
	* -Modified CALLEE_REG save/restore macros to handle the fact that
	* r25 contains the kernel current task ptr
	* - Defined Stack Switching Macro to be reused in all intr/excp hdlrs
	* - Shaved off 11 instructions from RESTORE_ALL_INT1 by using the
	* address Write back load ld.ab instead of seperate ld/add instn
	*
	* Amit Bhor, Sameer Dhavale: Codito Technologies 2004
	*/

	#ifndef __ASM_ARC_ENTRY_H
	#define __ASM_ARC_ENTRY_H

	#ifdef __ASSEMBLY__
	#include <asm/unistd.h> /* For NR_syscalls defination */
	#include <asm/asm-offsets.h>
	#include <asm/arcregs.h>
	#include <asm/ptrace.h>
	#include <asm/processor.h> /* For VMALLOC_START */
	#include <asm/thread_info.h> /* For THREAD_SIZE */

	/* Note on the LD/ST addr modes with addr reg wback
	*
	* LD.a same as LD.aw
	*
	* LD.a reg1, [reg2, x] => Pre Incr
	* Eff Addr for load = [reg2 + x]
	*
	* LD.ab reg1, [reg2, x] => Post Incr
	* Eff Addr for load = [reg2]
	*/

	/*--------------------------------------------------------------
	* Save caller saved registers (scratch registers) ( r0 - r12 )
	* Registers are pushed / popped in the order defined in struct ptregs
	* in asm/ptrace.h
	-------------------------------------------------------------/
	.macro SAVE_CALLER_SAVED
	st.a r0, [sp, -4]
	st.a r1, [sp, -4]
	st.a r2, [sp, -4]
	st.a r3, [sp, -4]
	st.a r4, [sp, -4]
	st.a r5, [sp, -4]
	st.a r6, [sp, -4]
	st.a r7, [sp, -4]
	st.a r8, [sp, -4]
	st.a r9, [sp, -4]
	st.a r10, [sp, -4]
	st.a r11, [sp, -4]
	st.a r12, [sp, -4]
	.endm

	/*--------------------------------------------------------------
	* Restore caller saved registers (scratch registers)
	-------------------------------------------------------------/
	.macro RESTORE_CALLER_SAVED
	ld.ab r12, [sp, 4]
	ld.ab r11, [sp, 4]
	ld.ab r10, [sp, 4]
	ld.ab r9, [sp, 4]
	ld.ab r8, [sp, 4]
	ld.ab r7, [sp, 4]
	ld.ab r6, [sp, 4]
	ld.ab r5, [sp, 4]
	ld.ab r4, [sp, 4]
	ld.ab r3, [sp, 4]
	ld.ab r2, [sp, 4]
	ld.ab r1, [sp, 4]
	ld.ab r0, [sp, 4]
	.endm


	/*--------------------------------------------------------------
	* Save callee saved registers (non scratch registers) ( r13 - r25 )
	* on kernel stack.
	* User mode callee regs need to be saved in case of
	* -fork and friends for replicating from parent to child
	* -before going into do_signal( ) for ptrace/core-dump
	* Special case handling is required for r25 in case it is used by kernel
	* for caching task ptr. Low level exception/ISR save user mode r25
	* into task->thread.user_r25. So it needs to be retrieved from there and
	* saved into kernel stack with rest of callee reg-file
	-------------------------------------------------------------/
	.macro SAVE_CALLEE_SAVED_USER
	st.a r13, [sp, -4]
	st.a r14, [sp, -4]
	st.a r15, [sp, -4]
	st.a r16, [sp, -4]
	st.a r17, [sp, -4]
	st.a r18, [sp, -4]
	st.a r19, [sp, -4]
	st.a r20, [sp, -4]
	st.a r21, [sp, -4]
	st.a r22, [sp, -4]
	st.a r23, [sp, -4]
	st.a r24, [sp, -4]

	#ifdef CONFIG_ARC_CURR_IN_REG
	; Retrieve orig r25 and save it on stack
	ld r12, [r25, TASK_THREAD + THREAD_USER_R25]
	st.a r12, [sp, -4]
	#else
	st.a r25, [sp, -4]
	#endif

	/* move up by 1 word to "create" callee_regs->"stack_place_holder" */
	sub sp, sp, 4
	.endm

	/*--------------------------------------------------------------
	* Save callee saved registers (non scratch registers) ( r13 - r25 )
	* kernel mode callee regs needed to be saved in case of context switch
	* If r25 is used for caching task pointer then that need not be saved
	* as it can be re-created from current task global
	-------------------------------------------------------------/
	.macro SAVE_CALLEE_SAVED_KERNEL
	st.a r13, [sp, -4]
	st.a r14, [sp, -4]
	st.a r15, [sp, -4]
	st.a r16, [sp, -4]
	st.a r17, [sp, -4]
	st.a r18, [sp, -4]
	st.a r19, [sp, -4]
	st.a r20, [sp, -4]
	st.a r21, [sp, -4]
	st.a r22, [sp, -4]
	st.a r23, [sp, -4]
	st.a r24, [sp, -4]
	#ifdef CONFIG_ARC_CURR_IN_REG
	sub sp, sp, 8
	#else
	st.a r25, [sp, -4]
	sub sp, sp, 4
	#endif
	.endm

	/*--------------------------------------------------------------
	* RESTORE_CALLEE_SAVED_KERNEL:
	* Loads callee (non scratch) Reg File by popping from Kernel mode stack.
	* This is reverse of SAVE_CALLEE_SAVED,
	*
	* NOTE:
	* Ideally this shd only be called in switch_to for loading
	* switched-IN task's CALLEE Reg File.
	* For all other cases RESTORE_CALLEE_SAVED_FAST must be used
	* which simply pops the stack w/o touching regs.
	-------------------------------------------------------------/
	.macro RESTORE_CALLEE_SAVED_KERNEL


	#ifdef CONFIG_ARC_CURR_IN_REG
	add sp, sp, 8 /* skip callee_reg gutter and user r25 placeholder */
	#else
	add sp, sp, 4 /* skip "callee_regs->stack_place_holder" */
	ld.ab r25, [sp, 4]
	#endif

	ld.ab r24, [sp, 4]
	ld.ab r23, [sp, 4]
	ld.ab r22, [sp, 4]
	ld.ab r21, [sp, 4]
	ld.ab r20, [sp, 4]
	ld.ab r19, [sp, 4]
	ld.ab r18, [sp, 4]
	ld.ab r17, [sp, 4]
	ld.ab r16, [sp, 4]
	ld.ab r15, [sp, 4]
	ld.ab r14, [sp, 4]
	ld.ab r13, [sp, 4]

	.endm

	/*--------------------------------------------------------------
	* RESTORE_CALLEE_SAVED_USER:
	* This is called after do_signal where tracer might have changed callee regs
	* thus we need to restore the reg file.
	* Special case handling is required for r25 in case it is used by kernel
	* for caching task ptr. Ptrace would have modified on-kernel-stack value of
	* r25, which needs to be shoved back into task->thread.user_r25 where from
	* Low level exception/ISR return code will retrieve to populate with rest of
	* callee reg-file.
	-------------------------------------------------------------/
	.macro RESTORE_CALLEE_SAVED_USER

	add sp, sp, 4 /* skip "callee_regs->stack_place_holder" */

	#ifdef CONFIG_ARC_CURR_IN_REG
	ld.ab r12, [sp, 4]
	st r12, [r25, TASK_THREAD + THREAD_USER_R25]
	#else
	ld.ab r25, [sp, 4]
	#endif

	ld.ab r24, [sp, 4]
	ld.ab r23, [sp, 4]
	ld.ab r22, [sp, 4]
	ld.ab r21, [sp, 4]
	ld.ab r20, [sp, 4]
	ld.ab r19, [sp, 4]
	ld.ab r18, [sp, 4]
	ld.ab r17, [sp, 4]
	ld.ab r16, [sp, 4]
	ld.ab r15, [sp, 4]
	ld.ab r14, [sp, 4]
	ld.ab r13, [sp, 4]
	.endm

	/*--------------------------------------------------------------
	* Super FAST Restore callee saved regs by simply re-adjusting SP
	-------------------------------------------------------------/
	.macro DISCARD_CALLEE_SAVED_USER
	add sp, sp, 14 * 4
	.endm

	/*--------------------------------------------------------------
	* Restore User mode r25 saved in task_struct->thread.user_r25
	-------------------------------------------------------------/
	.macro RESTORE_USER_R25
	ld r25, [r25, TASK_THREAD + THREAD_USER_R25]
	.endm

	/*-------------------------------------------------------------
	* given a tsk struct, get to the base of it's kernel mode stack
	* tsk->thread_info is really a PAGE, whose bottom hoists stack
	* which grows upwards towards thread_info
	------------------------------------------------------------/

	.macro GET_TSK_STACK_BASE tsk, out

	/* Get task->thread_info (this is essentially start of a PAGE) */
	ld \out, [\tsk, TASK_THREAD_INFO]

	/* Go to end of page where stack begins (grows upwards) */
	add2 \out, \out, (THREAD_SIZE - 4)/4 /* one word GUTTER */

	.endm

	/*--------------------------------------------------------------
	* Switch to Kernel Mode stack if SP points to User Mode stack
	*
	* Entry : r9 contains pre-IRQ/exception/trap status32
	* Exit : SP is set to kernel mode stack pointer
	* If CURR_IN_REG, r25 set to "current" task pointer
	* Clobbers: r9
	-------------------------------------------------------------/

	.macro SWITCH_TO_KERNEL_STK

	/* User Mode when this happened ? Yes: Proceed to switch stack */
	bbit1 r9, STATUS_U_BIT, 88f

	/* OK we were already in kernel mode when this event happened, thus can
	* assume SP is kernel mode SP. _NO_ need to do any stack switching
	*/

	#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS
	/* However....
	* If Level 2 Interrupts enabled, we may end up with a corner case:
	* 1. User Task executing
	* 2. L1 IRQ taken, ISR starts (CPU auto-switched to KERNEL mode)
	* 3. But before it could switch SP from USER to KERNEL stack
	* a L2 IRQ "Interrupts" L1
	* Thay way although L2 IRQ happened in Kernel mode, stack is still
	* not switched.
	* To handle this, we may need to switch stack even if in kernel mode
	* provided SP has values in range of USER mode stack ( < 0x7000_0000 )
	*/
	brlo sp, VMALLOC_START, 88f

	/* TODO: vineetg:
	* We need to be a bit more cautious here. What if a kernel bug in
	* L1 ISR, caused SP to go whaco (some small value which looks like
	* USER stk) and then we take L2 ISR.
	* Above brlo alone would treat it as a valid L1-L2 sceanrio
	* instead of shouting alound
	* The only feasible way is to make sure this L2 happened in
	* L1 prelogue ONLY i.e. ilink2 is less than a pre-set marker in
	* L1 ISR before it switches stack
	*/

	#endif

	/* Save Pre Intr/Exception KERNEL MODE SP on kernel stack
	* safe-keeping not really needed, but it keeps the epilogue code
	* (SP restore) simpler/uniform.
	*/
	b.d 77f

	st.a sp, [sp, -12] ; Make room for orig_r0 and orig_r8

	88: /------Intr/Ecxp happened in user mode, "switch" stack ------ /

	GET_CURR_TASK_ON_CPU r9

	#ifdef CONFIG_ARC_CURR_IN_REG

	/* If current task pointer cached in r25, time to
	* -safekeep USER r25 in task->thread_struct->user_r25
	* -load r25 with current task ptr
	*/
	st.as r25, [r9, (TASK_THREAD + THREAD_USER_R25)/4]
	mov r25, r9
	#endif

	/* With current tsk in r9, get it's kernel mode stack base */
	GET_TSK_STACK_BASE r9, r9

	#ifdef PT_REGS_CANARY
	st 0xabcdabcd, [r9, 0]
	#endif

	/* Save Pre Intr/Exception User SP on kernel stack */
	st.a sp, [r9, -12] ; Make room for orig_r0 and orig_r8

	/* CAUTION:
	* SP should be set at the very end when we are done with everything
	* In case of 2 levels of interrupt we depend on value of SP to assume
	* that everything else is done (loading r25 etc)
	*/

	/* set SP to point to kernel mode stack */
	mov sp, r9

	77: /* ----- Stack Switched to kernel Mode, Now save REG FILE ----- */

	.endm

	/*------------------------------------------------------------
	* "FAKE" a rtie to return from CPU Exception context
	* This is to re-enable Exceptions within exception
	* Look at EV_ProtV to see how this is actually used
	-------------------------------------------------------------/

	.macro FAKE_RET_FROM_EXCPN reg

	ld \reg, [sp, PT_status32]
	bic \reg, \reg, (STATUS_U_MASK\|STATUS_DE_MASK)
	bset \reg, \reg, STATUS_L_BIT
	sr \reg, [erstatus]
	mov \reg, 55f
	sr \reg, [eret]

	rtie
	55:
	.endm

	/*
	* @reg [OUT] &thread_info of "current"
	*/
	.macro GET_CURR_THR_INFO_FROM_SP reg
	and \reg, sp, ~(THREAD_SIZE - 1)
	.endm

	/*
	* @reg [OUT] thread_info->flags of "current"
	*/
	.macro GET_CURR_THR_INFO_FLAGS reg
	GET_CURR_THR_INFO_FROM_SP \reg
	ld \reg, [\reg, THREAD_INFO_FLAGS]
	.endm

	/*--------------------------------------------------------------
	* For early Exception Prologue, a core reg is temporarily needed to
	* code the rest of prolog (stack switching). This is done by stashing
	* it to memory (non-SMP case) or SCRATCH0 Aux Reg (SMP).
	*
	* Before saving the full regfile - this reg is restored back, only
	* to be saved again on kernel mode stack, as part of ptregs.
	-------------------------------------------------------------/
	.macro EXCPN_PROLOG_FREEUP_REG reg
	#ifdef CONFIG_SMP
	sr \reg, [ARC_REG_SCRATCH_DATA0]
	#else
	st \reg, [@ex_saved_reg1]
	#endif
	.endm

	.macro EXCPN_PROLOG_RESTORE_REG reg
	#ifdef CONFIG_SMP
	lr \reg, [ARC_REG_SCRATCH_DATA0]
	#else
	ld \reg, [@ex_saved_reg1]
	#endif
	.endm

	/*--------------------------------------------------------------
	* Save all registers used by Exceptions (TLB Miss, Prot-V, Mem err etc)
	* Requires SP to be already switched to kernel mode Stack
	* sp points to the next free element on the stack at exit of this macro.
	* Registers are pushed / popped in the order defined in struct ptregs
	* in asm/ptrace.h
	* Note that syscalls are implemented via TRAP which is also a exception
	* from CPU's point of view
	-------------------------------------------------------------/
	.macro SAVE_ALL_EXCEPTION marker

	st \marker, [sp, 8] /* orig_r8 */
	st r0, [sp, 4] /* orig_r0, needed only for sys calls */

	/* Restore r9 used to code the early prologue */
	EXCPN_PROLOG_RESTORE_REG r9

	SAVE_CALLER_SAVED
	st.a r26, [sp, -4] /* gp */
	st.a fp, [sp, -4]
	st.a blink, [sp, -4]
	lr r9, [eret]
	st.a r9, [sp, -4]
	lr r9, [erstatus]
	st.a r9, [sp, -4]
	st.a lp_count, [sp, -4]
	lr r9, [lp_end]
	st.a r9, [sp, -4]
	lr r9, [lp_start]
	st.a r9, [sp, -4]
	lr r9, [erbta]
	st.a r9, [sp, -4]

	#ifdef PT_REGS_CANARY
	mov r9, 0xdeadbeef
	st r9, [sp, -4]
	#endif

	/* move up by 1 word to "create" pt_regs->"stack_place_holder" */
	sub sp, sp, 4
	.endm

	/*--------------------------------------------------------------
	* Save scratch regs for exceptions
	-------------------------------------------------------------/
	.macro SAVE_ALL_SYS
	SAVE_ALL_EXCEPTION orig_r8_IS_EXCPN
	.endm

	/*--------------------------------------------------------------
	* Save scratch regs for sys calls
	-------------------------------------------------------------/
	.macro SAVE_ALL_TRAP
	/*
	* Setup pt_regs->orig_r8.
	* Encode syscall number (r8) in upper short word of event type (r9)
	* N.B. #1: This is already endian safe (see ptrace.h)
	* #2: Only r9 can be used as scratch as it is already clobbered
	* and it's contents are no longer needed by the latter part
	* of exception prologue
	*/
	lsl r9, r8, 16
	or r9, r9, orig_r8_IS_SCALL

	SAVE_ALL_EXCEPTION r9
	.endm

	/*--------------------------------------------------------------
	* Restore all registers used by system call or Exceptions
	* SP should always be pointing to the next free stack element
	* when entering this macro.
	*
	* NOTE:
	*
	* It is recommended that lp_count/ilink1/ilink2 not be used as a dest reg
	* for memory load operations. If used in that way interrupts are deffered
	* by hardware and that is not good.
	-------------------------------------------------------------/
	.macro RESTORE_ALL_SYS

	add sp, sp, 4 /* hop over unused "pt_regs->stack_place_holder" */

	ld.ab r9, [sp, 4]
	sr r9, [erbta]
	ld.ab r9, [sp, 4]
	sr r9, [lp_start]
	ld.ab r9, [sp, 4]
	sr r9, [lp_end]
	ld.ab r9, [sp, 4]
	mov lp_count, r9
	ld.ab r9, [sp, 4]
	sr r9, [erstatus]
	ld.ab r9, [sp, 4]
	sr r9, [eret]
	ld.ab blink, [sp, 4]
	ld.ab fp, [sp, 4]
	ld.ab r26, [sp, 4] /* gp */
	RESTORE_CALLER_SAVED

	ld sp, [sp] /* restore original sp */
	/* orig_r0 and orig_r8 skipped automatically */
	.endm


	/*--------------------------------------------------------------
	* Save all registers used by interrupt handlers.
	-------------------------------------------------------------/
	.macro SAVE_ALL_INT1

	/* restore original r9 , saved in int1_saved_reg
	* It will be saved on stack in macro: SAVE_CALLER_SAVED
	*/
	#ifdef CONFIG_SMP
	lr r9, [ARC_REG_SCRATCH_DATA0]
	#else
	ld r9, [@int1_saved_reg]
	#endif

	/* now we are ready to save the remaining context :) */
	st orig_r8_IS_IRQ1, [sp, 8] /* Event Type */
	st 0, [sp, 4] /* orig_r0 , N/A for IRQ */
	SAVE_CALLER_SAVED
	st.a r26, [sp, -4] /* gp */
	st.a fp, [sp, -4]
	st.a blink, [sp, -4]
	st.a ilink1, [sp, -4]
	lr r9, [status32_l1]
	st.a r9, [sp, -4]
	st.a lp_count, [sp, -4]
	lr r9, [lp_end]
	st.a r9, [sp, -4]
	lr r9, [lp_start]
	st.a r9, [sp, -4]
	lr r9, [bta_l1]
	st.a r9, [sp, -4]

	#ifdef PT_REGS_CANARY
	mov r9, 0xdeadbee1
	st r9, [sp, -4]
	#endif
	/* move up by 1 word to "create" pt_regs->"stack_place_holder" */
	sub sp, sp, 4
	.endm

	.macro SAVE_ALL_INT2

	/* TODO-vineetg: SMP we can't use global nor can we use
	* SCRATCH0 as we do for int1 because while int1 is using
	* it, int2 can come
	*/
	/* retsore original r9 , saved in sys_saved_r9 */
	ld r9, [@int2_saved_reg]

	/* now we are ready to save the remaining context :) */
	st orig_r8_IS_IRQ2, [sp, 8] /* Event Type */
	st 0, [sp, 4] /* orig_r0 , N/A for IRQ */
	SAVE_CALLER_SAVED
	st.a r26, [sp, -4] /* gp */
	st.a fp, [sp, -4]
	st.a blink, [sp, -4]
	st.a ilink2, [sp, -4]
	lr r9, [status32_l2]
	st.a r9, [sp, -4]
	st.a lp_count, [sp, -4]
	lr r9, [lp_end]
	st.a r9, [sp, -4]
	lr r9, [lp_start]
	st.a r9, [sp, -4]
	lr r9, [bta_l2]
	st.a r9, [sp, -4]

	#ifdef PT_REGS_CANARY
	mov r9, 0xdeadbee2
	st r9, [sp, -4]
	#endif

	/* move up by 1 word to "create" pt_regs->"stack_place_holder" */
	sub sp, sp, 4
	.endm

	/*--------------------------------------------------------------
	* Restore all registers used by interrupt handlers.
	*
	* NOTE:
	*
	* It is recommended that lp_count/ilink1/ilink2 not be used as a dest reg
	* for memory load operations. If used in that way interrupts are deffered
	* by hardware and that is not good.
	-------------------------------------------------------------/

	.macro RESTORE_ALL_INT1
	add sp, sp, 4 /* hop over unused "pt_regs->stack_place_holder" */

	ld.ab r9, [sp, 4] /* Actual reg file */
	sr r9, [bta_l1]
	ld.ab r9, [sp, 4]
	sr r9, [lp_start]
	ld.ab r9, [sp, 4]
	sr r9, [lp_end]
	ld.ab r9, [sp, 4]
	mov lp_count, r9
	ld.ab r9, [sp, 4]
	sr r9, [status32_l1]
	ld.ab r9, [sp, 4]
	mov ilink1, r9
	ld.ab blink, [sp, 4]
	ld.ab fp, [sp, 4]
	ld.ab r26, [sp, 4] /* gp */
	RESTORE_CALLER_SAVED

	ld sp, [sp] /* restore original sp */
	/* orig_r0 and orig_r8 skipped automatically */
	.endm

	.macro RESTORE_ALL_INT2
	add sp, sp, 4 /* hop over unused "pt_regs->stack_place_holder" */

	ld.ab r9, [sp, 4]
	sr r9, [bta_l2]
	ld.ab r9, [sp, 4]
	sr r9, [lp_start]
	ld.ab r9, [sp, 4]
	sr r9, [lp_end]
	ld.ab r9, [sp, 4]
	mov lp_count, r9
	ld.ab r9, [sp, 4]
	sr r9, [status32_l2]
	ld.ab r9, [sp, 4]
	mov ilink2, r9
	ld.ab blink, [sp, 4]
	ld.ab fp, [sp, 4]
	ld.ab r26, [sp, 4] /* gp */
	RESTORE_CALLER_SAVED

	ld sp, [sp] /* restore original sp */
	/* orig_r0 and orig_r8 skipped automatically */

	.endm


	/* Get CPU-ID of this core */
	.macro GET_CPU_ID reg
	lr \reg, [identity]
	lsr \reg, \reg, 8
	bmsk \reg, \reg, 7
	.endm

	#ifdef CONFIG_SMP

	/*-------------------------------------------------
	* Retrieve the current running task on this CPU
	* 1. Determine curr CPU id.
	* 2. Use it to index into _current_task[ ]
	*/
	.macro GET_CURR_TASK_ON_CPU reg
	GET_CPU_ID \reg
	ld.as \reg, [@_current_task, \reg]
	.endm

	/*-------------------------------------------------
	* Save a new task as the "current" task on this CPU
	* 1. Determine curr CPU id.
	* 2. Use it to index into _current_task[ ]
	*
	* Coded differently than GET_CURR_TASK_ON_CPU (which uses LD.AS)
	* because ST r0, [r1, offset] can ONLY have s9 @offset
	* while LD can take s9 (4 byte insn) or LIMM (8 byte insn)
	*/

	.macro SET_CURR_TASK_ON_CPU tsk, tmp
	GET_CPU_ID \tmp
	add2 \tmp, @_current_task, \tmp
	st \tsk, [\tmp]
	#ifdef CONFIG_ARC_CURR_IN_REG
	mov r25, \tsk
	#endif

	.endm


	#else /* Uniprocessor implementation of macros */

	.macro GET_CURR_TASK_ON_CPU reg
	ld \reg, [@_current_task]
	.endm

	.macro SET_CURR_TASK_ON_CPU tsk, tmp
	st \tsk, [@_current_task]
	#ifdef CONFIG_ARC_CURR_IN_REG
	mov r25, \tsk
	#endif
	.endm

	#endif /* SMP / UNI */

	/* ------------------------------------------------------------------
	* Get the ptr to some field of Current Task at @off in task struct
	* -Uses r25 for Current task ptr if that is enabled
	*/

	#ifdef CONFIG_ARC_CURR_IN_REG

	.macro GET_CURR_TASK_FIELD_PTR off, reg
	add \reg, r25, \off
	.endm

	#else

	.macro GET_CURR_TASK_FIELD_PTR off, reg
	GET_CURR_TASK_ON_CPU \reg
	add \reg, \reg, \off
	.endm

	#endif /* CONFIG_ARC_CURR_IN_REG */

	#endif /* __ASSEMBLY__ */

	#endif /* __ASM_ARC_ENTRY_H */