/*
   * 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.
   */
  
  #ifndef __ASM_ARC_ENTRY_H
  #define __ASM_ARC_ENTRY_H
  
  #include <asm/unistd.h>		/* For NR_syscalls defination */
  #include <asm/arcregs.h>
  #include <asm/ptrace.h>
  #include <asm/processor.h>	/* For VMALLOC_START */
  #include <asm/mmu.h>
  
  #ifdef CONFIG_ISA_ARCOMPACT
  #include <asm/entry-compact.h>	/* ISA specific bits */
  #else
  #include <asm/entry-arcv2.h>
  #endif
  
  /* 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]
   */
  
  .macro PUSH reg
  	st.a	\reg, [sp, -4]
  .endm
  
  .macro PUSHAX aux
  	lr	r9, [\aux]
  	PUSH	r9
  .endm
  
  .macro POP reg
  	ld.ab	\reg, [sp, 4]
  .endm
  
  .macro POPAX aux
  	POP	r9
  	sr	r9, [\aux]
  .endm
  
  /*--------------------------------------------------------------
   * Helpers to save/restore Scratch Regs:
   * used by Interrupt/Exception Prologue/Epilogue
   *-------------------------------------------------------------*/
  .macro  SAVE_R0_TO_R12
  	PUSH	r0
  	PUSH	r1
  	PUSH	r2
  	PUSH	r3
  	PUSH	r4
  	PUSH	r5
  	PUSH	r6
  	PUSH	r7
  	PUSH	r8
  	PUSH	r9
  	PUSH	r10
  	PUSH	r11
  	PUSH	r12
  .endm
  
  .macro RESTORE_R12_TO_R0
  	POP	r12
  	POP	r11
  	POP	r10
  	POP	r9
  	POP	r8
  	POP	r7
  	POP	r6
  	POP	r5
  	POP	r4
  	POP	r3
  	POP	r2
  	POP	r1
  	POP	r0
  
  #ifdef CONFIG_ARC_CURR_IN_REG
  	ld	r25, [sp, 12]
  #endif
  .endm
  
  /*--------------------------------------------------------------
   * Helpers to save/restore callee-saved regs:
   * used by several macros below
   *-------------------------------------------------------------*/
  .macro SAVE_R13_TO_R24
  	PUSH	r13
  	PUSH	r14
  	PUSH	r15
  	PUSH	r16
  	PUSH	r17
  	PUSH	r18
  	PUSH	r19
  	PUSH	r20
  	PUSH	r21
  	PUSH	r22
  	PUSH	r23
  	PUSH	r24
  .endm
  
  .macro RESTORE_R24_TO_R13
  	POP	r24
  	POP	r23
  	POP	r22
  	POP	r21
  	POP	r20
  	POP	r19
  	POP	r18
  	POP	r17
  	POP	r16
  	POP	r15
  	POP	r14
  	POP	r13
  .endm
  
  /*--------------------------------------------------------------
   * Collect User Mode callee regs as struct callee_regs - needed by
   * fork/do_signal/unaligned-access-emulation.
   * (By default only scratch regs are saved on entry to kernel)
   *
   * Special handling for r25 if used for caching Task Pointer.
   * It would have been saved in task->thread.user_r25 already, but to keep
   * the interface same it is copied into regular r25 placeholder in
   * struct callee_regs.
   *-------------------------------------------------------------*/
  .macro SAVE_CALLEE_SAVED_USER
  
  	mov	r12, sp		; save SP as ref to pt_regs
  	SAVE_R13_TO_R24
  
  #ifdef CONFIG_ARC_CURR_IN_REG
  	; Retrieve orig r25 and save it with rest of callee_regs
  	ld	r12, [r12, PT_user_r25]
  	PUSH	r12
  #else
  	PUSH	r25
  #endif
  
  .endm
  
  /*--------------------------------------------------------------
   * Save kernel Mode callee regs at the time of Contect Switch.
   *
   * Special handling for r25 if used for caching Task Pointer.
   * Kernel simply skips saving it since it will be loaded with
   * incoming task pointer anyways
   *-------------------------------------------------------------*/
  .macro SAVE_CALLEE_SAVED_KERNEL
  
  	SAVE_R13_TO_R24
  
  #ifdef CONFIG_ARC_CURR_IN_REG
  	sub     sp, sp, 4
  #else
  	PUSH	r25
  #endif
  .endm
  
  /*--------------------------------------------------------------
   * Opposite of SAVE_CALLEE_SAVED_KERNEL
   *-------------------------------------------------------------*/
  .macro RESTORE_CALLEE_SAVED_KERNEL
  
  #ifdef CONFIG_ARC_CURR_IN_REG
  	add     sp, sp, 4  /* skip usual r25 placeholder */
  #else
  	POP	r25
  #endif
  	RESTORE_R24_TO_R13
  .endm
  
  /*--------------------------------------------------------------
   * Opposite of SAVE_CALLEE_SAVED_USER
   *
   * ptrace tracer or unaligned-access fixup might have changed a user mode
   * callee reg which is saved back to usual r25 storage location
   *-------------------------------------------------------------*/
  .macro RESTORE_CALLEE_SAVED_USER
  
  #ifdef CONFIG_ARC_CURR_IN_REG
  	POP	r12
  #else
  	POP	r25
  #endif
  	RESTORE_R24_TO_R13
  
  	; SP is back to start of pt_regs
  #ifdef CONFIG_ARC_CURR_IN_REG
  	st	r12, [sp, PT_user_r25]
  #endif
  .endm
  
  /*--------------------------------------------------------------
   * Super FAST Restore callee saved regs by simply re-adjusting SP
   *-------------------------------------------------------------*/
  .macro DISCARD_CALLEE_SAVED_USER
  	add     sp, sp, SZ_CALLEE_REGS
  .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
  
  .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
  
  #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  /* __ASM_ARC_ENTRY_H */