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