arch/frv/kernel/switch_to.S

   1 ###############################################################################
   2 #
   3 # switch_to.S: context switch operation
   4 #
   5 # Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
   6 # Written by David Howells (dhowells@redhat.com)
   7 #
   8 # This program is free software; you can redistribute it and/or
   9 # modify it under the terms of the GNU General Public License
  10 # as published by the Free Software Foundation; either version
  11 # 2 of the License, or (at your option) any later version.
  12 #
  13 ###############################################################################
  14 #include <linux/config.h>
  15 #include <linux/linkage.h>
  16 #include <asm/thread_info.h>
  17 #include <asm/processor.h>
  18 #include <asm/registers.h>
  19 #include <asm/spr-regs.h>
  20
  21 .macro LEDS val
  22         setlos          #~\val,gr27
  23         st              gr27,@(gr30,gr0)
  24         membar
  25         dcf             @(gr30,gr0)
  26 .endm
  27
  28         .section        .sdata
  29         .balign         8
  30
  31         # address of frame 0 (userspace) on current kernel stack
  32         .globl          __kernel_frame0_ptr
  33 __kernel_frame0_ptr:
  34         .long           init_thread_union + THREAD_SIZE - USER_CONTEXT_SIZE
  35
  36         # address of current task
  37         .globl          __kernel_current_task
  38 __kernel_current_task:
  39         .long           init_task
  40
  41         .section        .text
  42         .balign         4
  43
  44 ###############################################################################
  45 #
  46 # struct task_struct *__switch_to(struct thread_struct *prev_thread,
  47 #                                 struct thread_struct *next_thread,
  48 #                                 struct task_struct *prev)
  49 #
  50 ###############################################################################
  51         .globl          __switch_to
  52 __switch_to:
  53         # save outgoing process's context
  54         sethi.p         %hi(__switch_back),gr13
  55         setlo           %lo(__switch_back),gr13
  56         movsg           lr,gr12
  57
  58         stdi            gr28,@(gr8,#__THREAD_FRAME)
  59         sti             sp  ,@(gr8,#__THREAD_SP)
  60         sti             fp  ,@(gr8,#__THREAD_FP)
  61         stdi            gr12,@(gr8,#__THREAD_LR)
  62         stdi            gr16,@(gr8,#__THREAD_GR(16))
  63         stdi            gr18,@(gr8,#__THREAD_GR(18))
  64         stdi            gr20,@(gr8,#__THREAD_GR(20))
  65         stdi            gr22,@(gr8,#__THREAD_GR(22))
  66         stdi            gr24,@(gr8,#__THREAD_GR(24))
  67         stdi.p          gr26,@(gr8,#__THREAD_GR(26))
  68
  69         or              gr8,gr8,gr22
  70         ldi.p           @(gr8,#__THREAD_USER),gr8
  71         call            save_user_regs
  72         or              gr22,gr22,gr8
  73
  74         # retrieve the new context
  75         sethi.p         %hi(__kernel_frame0_ptr),gr6
  76         setlo           %lo(__kernel_frame0_ptr),gr6
  77         movsg           psr,gr4
  78
  79         lddi.p          @(gr9,#__THREAD_FRAME),gr10
  80         or              gr10,gr10,gr27          ; save prev for the return value
  81
  82         ldi             @(gr11,#4),gr19         ; get new_current->thread_info
  83
  84         lddi            @(gr9,#__THREAD_SP),gr12
  85         ldi             @(gr9,#__THREAD_LR),gr14
  86         ldi             @(gr9,#__THREAD_PC),gr18
  87         ldi.p           @(gr9,#__THREAD_FRAME0),gr7
  88
  89         # actually switch kernel contexts with ordinary exceptions disabled
  90         andi            gr4,#~PSR_ET,gr5
  91         movgs           gr5,psr
  92
  93         or.p            gr10,gr0,gr28           ; set __frame
  94         or              gr11,gr0,gr29           ; set __current
  95         or.p            gr12,gr0,sp
  96         or              gr13,gr0,fp
  97         or              gr19,gr0,gr15           ; set __current_thread_info
  98
  99         sti             gr7,@(gr6,#0)           ; set __kernel_frame0_ptr
 100         sti             gr29,@(gr6,#4)          ; set __kernel_current_task
 101
 102         movgs           gr14,lr
 103         bar
 104
 105         srli            gr15,#28,gr5
 106         subicc          gr5,#0xc,gr0,icc0
 107         beq             icc0,#0,111f
 108         break
 109         nop
 110 111:
 111
 112         # jump to __switch_back or ret_from_fork as appropriate
 113         # - move prev to GR8
 114         movgs           gr4,psr
 115         jmpl.p          @(gr18,gr0)
 116         or              gr27,gr27,gr8
 117
 118 ###############################################################################
 119 #
 120 # restore incoming process's context
 121 # - on entry:
 122 #   - SP, FP, LR, GR15, GR28 and GR29 will have been set up appropriately
 123 #   - GR8 will point to the outgoing task_struct
 124 #   - GR9 will point to the incoming thread_struct
 125 #
 126 ###############################################################################
 127 __switch_back:
 128         lddi            @(gr9,#__THREAD_GR(16)),gr16
 129         lddi            @(gr9,#__THREAD_GR(18)),gr18
 130         lddi            @(gr9,#__THREAD_GR(20)),gr20
 131         lddi            @(gr9,#__THREAD_GR(22)),gr22
 132         lddi            @(gr9,#__THREAD_GR(24)),gr24
 133         lddi            @(gr9,#__THREAD_GR(26)),gr26
 134
 135         # fall through into restore_user_regs()
 136         ldi.p           @(gr9,#__THREAD_USER),gr8
 137         or              gr8,gr8,gr9
 138
 139 ###############################################################################
 140 #
 141 # restore extra general regs and FP/Media regs
 142 # - void *restore_user_regs(const struct user_context *target, void *retval)
 143 # - on entry:
 144 #   - GR8 will point to the user context to swap in
 145 #   - GR9 will contain the value to be returned in GR8 (prev task on context switch)
 146 #
 147 ###############################################################################
 148         .globl          restore_user_regs
 149 restore_user_regs:
 150         movsg           hsr0,gr6
 151         ori             gr6,#HSR0_GRHE|HSR0_FRLE|HSR0_FRHE,gr6
 152         movgs           gr6,hsr0
 153         movsg           hsr0,gr6
 154
 155         movsg           psr,gr7
 156         ori             gr7,#PSR_EF|PSR_EM,gr7
 157         movgs           gr7,psr
 158         movsg           psr,gr7
 159         srli            gr7,#24,gr7
 160         bar
 161
 162         lddi            @(gr8,#__FPMEDIA_MSR(0)),gr4
 163
 164         movgs           gr4,msr0
 165         movgs           gr5,msr1
 166
 167         lddfi           @(gr8,#__FPMEDIA_ACC(0)),fr16
 168         lddfi           @(gr8,#__FPMEDIA_ACC(2)),fr18
 169         ldbfi           @(gr8,#__FPMEDIA_ACCG(0)),fr20
 170         ldbfi           @(gr8,#__FPMEDIA_ACCG(1)),fr21
 171         ldbfi           @(gr8,#__FPMEDIA_ACCG(2)),fr22
 172         ldbfi           @(gr8,#__FPMEDIA_ACCG(3)),fr23
 173
 174         mwtacc          fr16,acc0
 175         mwtacc          fr17,acc1
 176         mwtacc          fr18,acc2
 177         mwtacc          fr19,acc3
 178         mwtaccg         fr20,accg0
 179         mwtaccg         fr21,accg1
 180         mwtaccg         fr22,accg2
 181         mwtaccg         fr23,accg3
 182
 183         # some CPUs have extra ACCx and ACCGx regs and maybe FSRx regs
 184         subicc.p        gr7,#0x50,gr0,icc0
 185         subicc          gr7,#0x31,gr0,icc1
 186         beq             icc0,#0,__restore_acc_fr451
 187         beq             icc1,#0,__restore_acc_fr555
 188 __restore_acc_cont:
 189
 190         # some CPU's have GR32-GR63
 191         setlos          #HSR0_FRHE,gr4
 192         andcc           gr6,gr4,gr0,icc0
 193         beq             icc0,#1,__restore_skip_gr32_gr63
 194
 195         lddi            @(gr8,#__INT_GR(32)),gr32
 196         lddi            @(gr8,#__INT_GR(34)),gr34
 197         lddi            @(gr8,#__INT_GR(36)),gr36
 198         lddi            @(gr8,#__INT_GR(38)),gr38
 199         lddi            @(gr8,#__INT_GR(40)),gr40
 200         lddi            @(gr8,#__INT_GR(42)),gr42
 201         lddi            @(gr8,#__INT_GR(44)),gr44
 202         lddi            @(gr8,#__INT_GR(46)),gr46
 203         lddi            @(gr8,#__INT_GR(48)),gr48
 204         lddi            @(gr8,#__INT_GR(50)),gr50
 205         lddi            @(gr8,#__INT_GR(52)),gr52
 206         lddi            @(gr8,#__INT_GR(54)),gr54
 207         lddi            @(gr8,#__INT_GR(56)),gr56
 208         lddi            @(gr8,#__INT_GR(58)),gr58
 209         lddi            @(gr8,#__INT_GR(60)),gr60
 210         lddi            @(gr8,#__INT_GR(62)),gr62
 211 __restore_skip_gr32_gr63:
 212
 213         # all CPU's have FR0-FR31
 214         lddfi           @(gr8,#__FPMEDIA_FR( 0)),fr0
 215         lddfi           @(gr8,#__FPMEDIA_FR( 2)),fr2
 216         lddfi           @(gr8,#__FPMEDIA_FR( 4)),fr4
 217         lddfi           @(gr8,#__FPMEDIA_FR( 6)),fr6
 218         lddfi           @(gr8,#__FPMEDIA_FR( 8)),fr8
 219         lddfi           @(gr8,#__FPMEDIA_FR(10)),fr10
 220         lddfi           @(gr8,#__FPMEDIA_FR(12)),fr12
 221         lddfi           @(gr8,#__FPMEDIA_FR(14)),fr14
 222         lddfi           @(gr8,#__FPMEDIA_FR(16)),fr16
 223         lddfi           @(gr8,#__FPMEDIA_FR(18)),fr18
 224         lddfi           @(gr8,#__FPMEDIA_FR(20)),fr20
 225         lddfi           @(gr8,#__FPMEDIA_FR(22)),fr22
 226         lddfi           @(gr8,#__FPMEDIA_FR(24)),fr24
 227         lddfi           @(gr8,#__FPMEDIA_FR(26)),fr26
 228         lddfi           @(gr8,#__FPMEDIA_FR(28)),fr28
 229         lddfi.p         @(gr8,#__FPMEDIA_FR(30)),fr30
 230
 231         # some CPU's have FR32-FR63
 232         setlos          #HSR0_FRHE,gr4
 233         andcc           gr6,gr4,gr0,icc0
 234         beq             icc0,#1,__restore_skip_fr32_fr63
 235
 236         lddfi           @(gr8,#__FPMEDIA_FR(32)),fr32
 237         lddfi           @(gr8,#__FPMEDIA_FR(34)),fr34
 238         lddfi           @(gr8,#__FPMEDIA_FR(36)),fr36
 239         lddfi           @(gr8,#__FPMEDIA_FR(38)),fr38
 240         lddfi           @(gr8,#__FPMEDIA_FR(40)),fr40
 241         lddfi           @(gr8,#__FPMEDIA_FR(42)),fr42
 242         lddfi           @(gr8,#__FPMEDIA_FR(44)),fr44
 243         lddfi           @(gr8,#__FPMEDIA_FR(46)),fr46
 244         lddfi           @(gr8,#__FPMEDIA_FR(48)),fr48
 245         lddfi           @(gr8,#__FPMEDIA_FR(50)),fr50
 246         lddfi           @(gr8,#__FPMEDIA_FR(52)),fr52
 247         lddfi           @(gr8,#__FPMEDIA_FR(54)),fr54
 248         lddfi           @(gr8,#__FPMEDIA_FR(56)),fr56
 249         lddfi           @(gr8,#__FPMEDIA_FR(58)),fr58
 250         lddfi           @(gr8,#__FPMEDIA_FR(60)),fr60
 251         lddfi           @(gr8,#__FPMEDIA_FR(62)),fr62
 252 __restore_skip_fr32_fr63:
 253
 254         lddi            @(gr8,#__FPMEDIA_FNER(0)),gr4
 255         movsg           fner0,gr4
 256         movsg           fner1,gr5
 257         or.p            gr9,gr9,gr8
 258         bralr
 259
 260         # the FR451 also has ACC8-11/ACCG8-11 regs (but not 4-7...)
 261 __restore_acc_fr451:
 262         lddfi           @(gr8,#__FPMEDIA_ACC(4)),fr16
 263         lddfi           @(gr8,#__FPMEDIA_ACC(6)),fr18
 264         ldbfi           @(gr8,#__FPMEDIA_ACCG(4)),fr20
 265         ldbfi           @(gr8,#__FPMEDIA_ACCG(5)),fr21
 266         ldbfi           @(gr8,#__FPMEDIA_ACCG(6)),fr22
 267         ldbfi           @(gr8,#__FPMEDIA_ACCG(7)),fr23
 268
 269         mwtacc          fr16,acc8
 270         mwtacc          fr17,acc9
 271         mwtacc          fr18,acc10
 272         mwtacc          fr19,acc11
 273         mwtaccg         fr20,accg8
 274         mwtaccg         fr21,accg9
 275         mwtaccg         fr22,accg10
 276         mwtaccg         fr23,accg11
 277         bra             __restore_acc_cont
 278
 279         # the FR555 also has ACC4-7/ACCG4-7 regs and an FSR0 reg
 280 __restore_acc_fr555:
 281         lddfi           @(gr8,#__FPMEDIA_ACC(4)),fr16
 282         lddfi           @(gr8,#__FPMEDIA_ACC(6)),fr18
 283         ldbfi           @(gr8,#__FPMEDIA_ACCG(4)),fr20
 284         ldbfi           @(gr8,#__FPMEDIA_ACCG(5)),fr21
 285         ldbfi           @(gr8,#__FPMEDIA_ACCG(6)),fr22
 286         ldbfi           @(gr8,#__FPMEDIA_ACCG(7)),fr23
 287
 288         mnop.p
 289         mwtacc          fr16,acc4
 290         mnop.p
 291         mwtacc          fr17,acc5
 292         mnop.p
 293         mwtacc          fr18,acc6
 294         mnop.p
 295         mwtacc          fr19,acc7
 296         mnop.p
 297         mwtaccg         fr20,accg4
 298         mnop.p
 299         mwtaccg         fr21,accg5
 300         mnop.p
 301         mwtaccg         fr22,accg6
 302         mnop.p
 303         mwtaccg         fr23,accg7
 304
 305         ldi             @(gr8,#__FPMEDIA_FSR(0)),gr4
 306         movgs           gr4,fsr0
 307
 308         bra             __restore_acc_cont
 309
 310
 311 ###############################################################################
 312 #
 313 # save extra general regs and FP/Media regs
 314 # - void save_user_regs(struct user_context *target)
 315 #
 316 ###############################################################################
 317         .globl          save_user_regs
 318 save_user_regs:
 319         movsg           hsr0,gr6
 320         ori             gr6,#HSR0_GRHE|HSR0_FRLE|HSR0_FRHE,gr6
 321         movgs           gr6,hsr0
 322         movsg           hsr0,gr6
 323
 324         movsg           psr,gr7
 325         ori             gr7,#PSR_EF|PSR_EM,gr7
 326         movgs           gr7,psr
 327         movsg           psr,gr7
 328         srli            gr7,#24,gr7
 329         bar
 330
 331         movsg           fner0,gr4
 332         movsg           fner1,gr5
 333         stdi.p          gr4,@(gr8,#__FPMEDIA_FNER(0))
 334
 335         # some CPU's have GR32-GR63
 336         setlos          #HSR0_GRHE,gr4
 337         andcc           gr6,gr4,gr0,icc0
 338         beq             icc0,#1,__save_skip_gr32_gr63
 339
 340         stdi            gr32,@(gr8,#__INT_GR(32))
 341         stdi            gr34,@(gr8,#__INT_GR(34))
 342         stdi            gr36,@(gr8,#__INT_GR(36))
 343         stdi            gr38,@(gr8,#__INT_GR(38))
 344         stdi            gr40,@(gr8,#__INT_GR(40))
 345         stdi            gr42,@(gr8,#__INT_GR(42))
 346         stdi            gr44,@(gr8,#__INT_GR(44))
 347         stdi            gr46,@(gr8,#__INT_GR(46))
 348         stdi            gr48,@(gr8,#__INT_GR(48))
 349         stdi            gr50,@(gr8,#__INT_GR(50))
 350         stdi            gr52,@(gr8,#__INT_GR(52))
 351         stdi            gr54,@(gr8,#__INT_GR(54))
 352         stdi            gr56,@(gr8,#__INT_GR(56))
 353         stdi            gr58,@(gr8,#__INT_GR(58))
 354         stdi            gr60,@(gr8,#__INT_GR(60))
 355         stdi            gr62,@(gr8,#__INT_GR(62))
 356 __save_skip_gr32_gr63:
 357
 358         # all CPU's have FR0-FR31
 359         stdfi           fr0 ,@(gr8,#__FPMEDIA_FR( 0))
 360         stdfi           fr2 ,@(gr8,#__FPMEDIA_FR( 2))
 361         stdfi           fr4 ,@(gr8,#__FPMEDIA_FR( 4))
 362         stdfi           fr6 ,@(gr8,#__FPMEDIA_FR( 6))
 363         stdfi           fr8 ,@(gr8,#__FPMEDIA_FR( 8))
 364         stdfi           fr10,@(gr8,#__FPMEDIA_FR(10))
 365         stdfi           fr12,@(gr8,#__FPMEDIA_FR(12))
 366         stdfi           fr14,@(gr8,#__FPMEDIA_FR(14))
 367         stdfi           fr16,@(gr8,#__FPMEDIA_FR(16))
 368         stdfi           fr18,@(gr8,#__FPMEDIA_FR(18))
 369         stdfi           fr20,@(gr8,#__FPMEDIA_FR(20))
 370         stdfi           fr22,@(gr8,#__FPMEDIA_FR(22))
 371         stdfi           fr24,@(gr8,#__FPMEDIA_FR(24))
 372         stdfi           fr26,@(gr8,#__FPMEDIA_FR(26))
 373         stdfi           fr28,@(gr8,#__FPMEDIA_FR(28))
 374         stdfi.p         fr30,@(gr8,#__FPMEDIA_FR(30))
 375
 376         # some CPU's have FR32-FR63
 377         setlos          #HSR0_FRHE,gr4
 378         andcc           gr6,gr4,gr0,icc0
 379         beq             icc0,#1,__save_skip_fr32_fr63
 380
 381         stdfi           fr32,@(gr8,#__FPMEDIA_FR(32))
 382         stdfi           fr34,@(gr8,#__FPMEDIA_FR(34))
 383         stdfi           fr36,@(gr8,#__FPMEDIA_FR(36))
 384         stdfi           fr38,@(gr8,#__FPMEDIA_FR(38))
 385         stdfi           fr40,@(gr8,#__FPMEDIA_FR(40))
 386         stdfi           fr42,@(gr8,#__FPMEDIA_FR(42))
 387         stdfi           fr44,@(gr8,#__FPMEDIA_FR(44))
 388         stdfi           fr46,@(gr8,#__FPMEDIA_FR(46))
 389         stdfi           fr48,@(gr8,#__FPMEDIA_FR(48))
 390         stdfi           fr50,@(gr8,#__FPMEDIA_FR(50))
 391         stdfi           fr52,@(gr8,#__FPMEDIA_FR(52))
 392         stdfi           fr54,@(gr8,#__FPMEDIA_FR(54))
 393         stdfi           fr56,@(gr8,#__FPMEDIA_FR(56))
 394         stdfi           fr58,@(gr8,#__FPMEDIA_FR(58))
 395         stdfi           fr60,@(gr8,#__FPMEDIA_FR(60))
 396         stdfi           fr62,@(gr8,#__FPMEDIA_FR(62))
 397 __save_skip_fr32_fr63:
 398
 399         mrdacc          acc0 ,fr4
 400         mrdacc          acc1 ,fr5
 401
 402         stdfi.p         fr4 ,@(gr8,#__FPMEDIA_ACC(0))
 403
 404         mrdacc          acc2 ,fr6
 405         mrdacc          acc3 ,fr7
 406
 407         stdfi.p         fr6 ,@(gr8,#__FPMEDIA_ACC(2))
 408
 409         mrdaccg         accg0,fr4
 410         stbfi.p         fr4 ,@(gr8,#__FPMEDIA_ACCG(0))
 411
 412         mrdaccg         accg1,fr5
 413         stbfi.p         fr5 ,@(gr8,#__FPMEDIA_ACCG(1))
 414
 415         mrdaccg         accg2,fr6
 416         stbfi.p         fr6 ,@(gr8,#__FPMEDIA_ACCG(2))
 417
 418         mrdaccg         accg3,fr7
 419         stbfi           fr7 ,@(gr8,#__FPMEDIA_ACCG(3))
 420
 421         movsg           msr0 ,gr4
 422         movsg           msr1 ,gr5
 423
 424         stdi            gr4 ,@(gr8,#__FPMEDIA_MSR(0))
 425
 426         # some CPUs have extra ACCx and ACCGx regs and maybe FSRx regs
 427         subicc.p        gr7,#0x50,gr0,icc0
 428         subicc          gr7,#0x31,gr0,icc1
 429         beq             icc0,#0,__save_acc_fr451
 430         beq             icc1,#0,__save_acc_fr555
 431 __save_acc_cont:
 432
 433         lddfi           @(gr8,#__FPMEDIA_FR(4)),fr4
 434         lddfi.p         @(gr8,#__FPMEDIA_FR(6)),fr6
 435         bralr
 436
 437         # the FR451 also has ACC8-11/ACCG8-11 regs (but not 4-7...)
 438 __save_acc_fr451:
 439         mrdacc          acc8 ,fr4
 440         mrdacc          acc9 ,fr5
 441
 442         stdfi.p         fr4 ,@(gr8,#__FPMEDIA_ACC(4))
 443
 444         mrdacc          acc10,fr6
 445         mrdacc          acc11,fr7
 446
 447         stdfi.p         fr6 ,@(gr8,#__FPMEDIA_ACC(6))
 448
 449         mrdaccg         accg8,fr4
 450         stbfi.p         fr4 ,@(gr8,#__FPMEDIA_ACCG(4))
 451
 452         mrdaccg         accg9,fr5
 453         stbfi.p         fr5 ,@(gr8,#__FPMEDIA_ACCG(5))
 454
 455         mrdaccg         accg10,fr6
 456         stbfi.p         fr6 ,@(gr8,#__FPMEDIA_ACCG(6))
 457
 458         mrdaccg         accg11,fr7
 459         stbfi           fr7 ,@(gr8,#__FPMEDIA_ACCG(7))
 460         bra             __save_acc_cont
 461
 462         # the FR555 also has ACC4-7/ACCG4-7 regs and an FSR0 reg
 463 __save_acc_fr555:
 464         mnop.p
 465         mrdacc          acc4 ,fr4
 466         mnop.p
 467         mrdacc          acc5 ,fr5
 468
 469         stdfi           fr4 ,@(gr8,#__FPMEDIA_ACC(4))
 470
 471         mnop.p
 472         mrdacc          acc6 ,fr6
 473         mnop.p
 474         mrdacc          acc7 ,fr7
 475
 476         stdfi           fr6 ,@(gr8,#__FPMEDIA_ACC(6))
 477
 478         mnop.p
 479         mrdaccg         accg4,fr4
 480         stbfi           fr4 ,@(gr8,#__FPMEDIA_ACCG(4))
 481
 482         mnop.p
 483         mrdaccg         accg5,fr5
 484         stbfi           fr5 ,@(gr8,#__FPMEDIA_ACCG(5))
 485
 486         mnop.p
 487         mrdaccg         accg6,fr6
 488         stbfi           fr6 ,@(gr8,#__FPMEDIA_ACCG(6))
 489
 490         mnop.p
 491         mrdaccg         accg7,fr7
 492         stbfi           fr7 ,@(gr8,#__FPMEDIA_ACCG(7))
 493
 494         movsg           fsr0 ,gr4
 495         sti             gr4 ,@(gr8,#__FPMEDIA_FSR(0))
 496         bra             __save_acc_cont