arch/arc/include/asm/entry.h

   1 /*
   2  * Copyright (C) 2014-15 Synopsys, Inc. (www.synopsys.com)
   3  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  */
   9
  10 #ifndef __ASM_ARC_ENTRY_H
  11 #define __ASM_ARC_ENTRY_H
  12
  13 #include <asm/unistd.h>         /* For NR_syscalls defination */
  14 #include <asm/arcregs.h>
  15 #include <asm/ptrace.h>
  16 #include <asm/processor.h>      /* For VMALLOC_START */
  17 #include <asm/mmu.h>
  18
  19 #ifdef CONFIG_ISA_ARCOMPACT
  20 #include <asm/entry-compact.h>  /* ISA specific bits */
  21 #else
  22 #include <asm/entry-arcv2.h>
  23 #endif
  24
  25 /* Note on the LD/ST addr modes with addr reg wback
  26  *
  27  * LD.a same as LD.aw
  28  *
  29  * LD.a    reg1, [reg2, x]  => Pre Incr
  30  *      Eff Addr for load = [reg2 + x]
  31  *
  32  * LD.ab   reg1, [reg2, x]  => Post Incr
  33  *      Eff Addr for load = [reg2]
  34  */
  35
  36 .macro PUSH reg
  37         st.a    \reg, [sp, -4]
  38 .endm
  39
  40 .macro PUSHAX aux
  41         lr      r9, [\aux]
  42         PUSH    r9
  43 .endm
  44
  45 .macro POP reg
  46         ld.ab   \reg, [sp, 4]
  47 .endm
  48
  49 .macro POPAX aux
  50         POP     r9
  51         sr      r9, [\aux]
  52 .endm
  53
  54 /*--------------------------------------------------------------
  55  * Helpers to save/restore Scratch Regs:
  56  * used by Interrupt/Exception Prologue/Epilogue
  57  *-------------------------------------------------------------*/
  58 .macro  SAVE_R0_TO_R12
  59         PUSH    r0
  60         PUSH    r1
  61         PUSH    r2
  62         PUSH    r3
  63         PUSH    r4
  64         PUSH    r5
  65         PUSH    r6
  66         PUSH    r7
  67         PUSH    r8
  68         PUSH    r9
  69         PUSH    r10
  70         PUSH    r11
  71         PUSH    r12
  72 .endm
  73
  74 .macro RESTORE_R12_TO_R0
  75         POP     r12
  76         POP     r11
  77         POP     r10
  78         POP     r9
  79         POP     r8
  80         POP     r7
  81         POP     r6
  82         POP     r5
  83         POP     r4
  84         POP     r3
  85         POP     r2
  86         POP     r1
  87         POP     r0
  88
  89 .endm
  90
  91 /*--------------------------------------------------------------
  92  * Helpers to save/restore callee-saved regs:
  93  * used by several macros below
  94  *-------------------------------------------------------------*/
  95 .macro SAVE_R13_TO_R24
  96         PUSH    r13
  97         PUSH    r14
  98         PUSH    r15
  99         PUSH    r16
 100         PUSH    r17
 101         PUSH    r18
 102         PUSH    r19
 103         PUSH    r20
 104         PUSH    r21
 105         PUSH    r22
 106         PUSH    r23
 107         PUSH    r24
 108 .endm
 109
 110 .macro RESTORE_R24_TO_R13
 111         POP     r24
 112         POP     r23
 113         POP     r22
 114         POP     r21
 115         POP     r20
 116         POP     r19
 117         POP     r18
 118         POP     r17
 119         POP     r16
 120         POP     r15
 121         POP     r14
 122         POP     r13
 123 .endm
 124
 125 /*--------------------------------------------------------------
 126  * Collect User Mode callee regs as struct callee_regs - needed by
 127  * fork/do_signal/unaligned-access-emulation.
 128  * (By default only scratch regs are saved on entry to kernel)
 129  *
 130  * Special handling for r25 if used for caching Task Pointer.
 131  * It would have been saved in task->thread.user_r25 already, but to keep
 132  * the interface same it is copied into regular r25 placeholder in
 133  * struct callee_regs.
 134  *-------------------------------------------------------------*/
 135 .macro SAVE_CALLEE_SAVED_USER
 136
 137         mov     r12, sp         ; save SP as ref to pt_regs
 138         SAVE_R13_TO_R24
 139
 140 #ifdef CONFIG_ARC_CURR_IN_REG
 141         ; Retrieve orig r25 and save it with rest of callee_regs
 142         ld      r12, [r12, PT_user_r25]
 143         PUSH    r12
 144 #else
 145         PUSH    r25
 146 #endif
 147
 148 .endm
 149
 150 /*--------------------------------------------------------------
 151  * Save kernel Mode callee regs at the time of Contect Switch.
 152  *
 153  * Special handling for r25 if used for caching Task Pointer.
 154  * Kernel simply skips saving it since it will be loaded with
 155  * incoming task pointer anyways
 156  *-------------------------------------------------------------*/
 157 .macro SAVE_CALLEE_SAVED_KERNEL
 158
 159         SAVE_R13_TO_R24
 160
 161 #ifdef CONFIG_ARC_CURR_IN_REG
 162         sub     sp, sp, 4
 163 #else
 164         PUSH    r25
 165 #endif
 166 .endm
 167
 168 /*--------------------------------------------------------------
 169  * Opposite of SAVE_CALLEE_SAVED_KERNEL
 170  *-------------------------------------------------------------*/
 171 .macro RESTORE_CALLEE_SAVED_KERNEL
 172
 173 #ifdef CONFIG_ARC_CURR_IN_REG
 174         add     sp, sp, 4  /* skip usual r25 placeholder */
 175 #else
 176         POP     r25
 177 #endif
 178         RESTORE_R24_TO_R13
 179 .endm
 180
 181 /*--------------------------------------------------------------
 182  * Opposite of SAVE_CALLEE_SAVED_USER
 183  *
 184  * ptrace tracer or unaligned-access fixup might have changed a user mode
 185  * callee reg which is saved back to usual r25 storage location
 186  *-------------------------------------------------------------*/
 187 .macro RESTORE_CALLEE_SAVED_USER
 188
 189 #ifdef CONFIG_ARC_CURR_IN_REG
 190         POP     r12
 191 #else
 192         POP     r25
 193 #endif
 194         RESTORE_R24_TO_R13
 195
 196         ; SP is back to start of pt_regs
 197 #ifdef CONFIG_ARC_CURR_IN_REG
 198         st      r12, [sp, PT_user_r25]
 199 #endif
 200 .endm
 201
 202 /*--------------------------------------------------------------
 203  * Super FAST Restore callee saved regs by simply re-adjusting SP
 204  *-------------------------------------------------------------*/
 205 .macro DISCARD_CALLEE_SAVED_USER
 206         add     sp, sp, SZ_CALLEE_REGS
 207 .endm
 208
 209 /*-------------------------------------------------------------
 210  * given a tsk struct, get to the base of it's kernel mode stack
 211  * tsk->thread_info is really a PAGE, whose bottom hoists stack
 212  * which grows upwards towards thread_info
 213  *------------------------------------------------------------*/
 214
 215 .macro GET_TSK_STACK_BASE tsk, out
 216
 217         /* Get task->thread_info (this is essentially start of a PAGE) */
 218         ld  \out, [\tsk, TASK_THREAD_INFO]
 219
 220         /* Go to end of page where stack begins (grows upwards) */
 221         add2 \out, \out, (THREAD_SIZE)/4
 222
 223 .endm
 224
 225 /*
 226  * @reg [OUT] thread_info->flags of "current"
 227  */
 228 .macro GET_CURR_THR_INFO_FLAGS  reg
 229         GET_CURR_THR_INFO_FROM_SP  \reg
 230         ld  \reg, [\reg, THREAD_INFO_FLAGS]
 231 .endm
 232
 233 #ifdef CONFIG_SMP
 234
 235 /*-------------------------------------------------
 236  * Retrieve the current running task on this CPU
 237  * 1. Determine curr CPU id.
 238  * 2. Use it to index into _current_task[ ]
 239  */
 240 .macro  GET_CURR_TASK_ON_CPU   reg
 241         GET_CPU_ID  \reg
 242         ld.as  \reg, [@_current_task, \reg]
 243 .endm
 244
 245 /*-------------------------------------------------
 246  * Save a new task as the "current" task on this CPU
 247  * 1. Determine curr CPU id.
 248  * 2. Use it to index into _current_task[ ]
 249  *
 250  * Coded differently than GET_CURR_TASK_ON_CPU (which uses LD.AS)
 251  * because ST r0, [r1, offset] can ONLY have s9 @offset
 252  * while   LD can take s9 (4 byte insn) or LIMM (8 byte insn)
 253  */
 254
 255 .macro  SET_CURR_TASK_ON_CPU    tsk, tmp
 256         GET_CPU_ID  \tmp
 257         add2 \tmp, @_current_task, \tmp
 258         st   \tsk, [\tmp]
 259 #ifdef CONFIG_ARC_CURR_IN_REG
 260         mov r25, \tsk
 261 #endif
 262
 263 .endm
 264
 265
 266 #else   /* Uniprocessor implementation of macros */
 267
 268 .macro  GET_CURR_TASK_ON_CPU    reg
 269         ld  \reg, [@_current_task]
 270 .endm
 271
 272 .macro  SET_CURR_TASK_ON_CPU    tsk, tmp
 273         st  \tsk, [@_current_task]
 274 #ifdef CONFIG_ARC_CURR_IN_REG
 275         mov r25, \tsk
 276 #endif
 277 .endm
 278
 279 #endif /* SMP / UNI */
 280
 281 /* ------------------------------------------------------------------
 282  * Get the ptr to some field of Current Task at @off in task struct
 283  *  -Uses r25 for Current task ptr if that is enabled
 284  */
 285
 286 #ifdef CONFIG_ARC_CURR_IN_REG
 287
 288 .macro GET_CURR_TASK_FIELD_PTR  off,  reg
 289         add \reg, r25, \off
 290 .endm
 291
 292 #else
 293
 294 .macro GET_CURR_TASK_FIELD_PTR  off,  reg
 295         GET_CURR_TASK_ON_CPU  \reg
 296         add \reg, \reg, \off
 297 .endm
 298
 299 #endif  /* CONFIG_ARC_CURR_IN_REG */
 300
 301 #endif  /* __ASM_ARC_ENTRY_H */