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
  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 - FRV_FRAME0_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         # jump to __switch_back or ret_from_fork as appropriate
 106         # - move prev to GR8
 107         movgs           gr4,psr
 108         jmpl.p          @(gr18,gr0)
 109         or              gr27,gr27,gr8
 110
 111 ###############################################################################
 112 #
 113 # restore incoming process's context
 114 # - on entry:
 115 #   - SP, FP, LR, GR15, GR28 and GR29 will have been set up appropriately
 116 #   - GR8 will point to the outgoing task_struct
 117 #   - GR9 will point to the incoming thread_struct
 118 #
 119 ###############################################################################
 120 __switch_back:
 121         lddi            @(gr9,#__THREAD_GR(16)),gr16
 122         lddi            @(gr9,#__THREAD_GR(18)),gr18
 123         lddi            @(gr9,#__THREAD_GR(20)),gr20
 124         lddi            @(gr9,#__THREAD_GR(22)),gr22
 125         lddi            @(gr9,#__THREAD_GR(24)),gr24
 126         lddi            @(gr9,#__THREAD_GR(26)),gr26
 127
 128         # fall through into restore_user_regs()
 129         ldi.p           @(gr9,#__THREAD_USER),gr8
 130         or              gr8,gr8,gr9
 131
 132 ###############################################################################
 133 #
 134 # restore extra general regs and FP/Media regs
 135 # - void *restore_user_regs(const struct user_context *target, void *retval)
 136 # - on entry:
 137 #   - GR8 will point to the user context to swap in
 138 #   - GR9 will contain the value to be returned in GR8 (prev task on context switch)
 139 #
 140 ###############################################################################
 141         .globl          restore_user_regs
 142 restore_user_regs:
 143         movsg           hsr0,gr6
 144         ori             gr6,#HSR0_GRHE|HSR0_FRLE|HSR0_FRHE,gr6
 145         movgs           gr6,hsr0
 146         movsg           hsr0,gr6
 147
 148         movsg           psr,gr7
 149         ori             gr7,#PSR_EF|PSR_EM,gr7
 150         movgs           gr7,psr
 151         movsg           psr,gr7
 152         srli            gr7,#24,gr7
 153         bar
 154
 155         lddi            @(gr8,#__FPMEDIA_MSR(0)),gr4
 156
 157         movgs           gr4,msr0
 158         movgs           gr5,msr1
 159
 160         lddfi           @(gr8,#__FPMEDIA_ACC(0)),fr16
 161         lddfi           @(gr8,#__FPMEDIA_ACC(2)),fr18
 162         ldbfi           @(gr8,#__FPMEDIA_ACCG(0)),fr20
 163         ldbfi           @(gr8,#__FPMEDIA_ACCG(1)),fr21
 164         ldbfi           @(gr8,#__FPMEDIA_ACCG(2)),fr22
 165         ldbfi           @(gr8,#__FPMEDIA_ACCG(3)),fr23
 166
 167         mwtacc          fr16,acc0
 168         mwtacc          fr17,acc1
 169         mwtacc          fr18,acc2
 170         mwtacc          fr19,acc3
 171         mwtaccg         fr20,accg0
 172         mwtaccg         fr21,accg1
 173         mwtaccg         fr22,accg2
 174         mwtaccg         fr23,accg3
 175
 176         # some CPUs have extra ACCx and ACCGx regs and maybe FSRx regs
 177         subicc.p        gr7,#0x50,gr0,icc0
 178         subicc          gr7,#0x31,gr0,icc1
 179         beq             icc0,#0,__restore_acc_fr451
 180         beq             icc1,#0,__restore_acc_fr555
 181 __restore_acc_cont:
 182
 183         # some CPU's have GR32-GR63
 184         setlos          #HSR0_FRHE,gr4
 185         andcc           gr6,gr4,gr0,icc0
 186         beq             icc0,#1,__restore_skip_gr32_gr63
 187
 188         lddi            @(gr8,#__INT_GR(32)),gr32
 189         lddi            @(gr8,#__INT_GR(34)),gr34
 190         lddi            @(gr8,#__INT_GR(36)),gr36
 191         lddi            @(gr8,#__INT_GR(38)),gr38
 192         lddi            @(gr8,#__INT_GR(40)),gr40
 193         lddi            @(gr8,#__INT_GR(42)),gr42
 194         lddi            @(gr8,#__INT_GR(44)),gr44
 195         lddi            @(gr8,#__INT_GR(46)),gr46
 196         lddi            @(gr8,#__INT_GR(48)),gr48
 197         lddi            @(gr8,#__INT_GR(50)),gr50
 198         lddi            @(gr8,#__INT_GR(52)),gr52
 199         lddi            @(gr8,#__INT_GR(54)),gr54
 200         lddi            @(gr8,#__INT_GR(56)),gr56
 201         lddi            @(gr8,#__INT_GR(58)),gr58
 202         lddi            @(gr8,#__INT_GR(60)),gr60
 203         lddi            @(gr8,#__INT_GR(62)),gr62
 204 __restore_skip_gr32_gr63:
 205
 206         # all CPU's have FR0-FR31
 207         lddfi           @(gr8,#__FPMEDIA_FR( 0)),fr0
 208         lddfi           @(gr8,#__FPMEDIA_FR( 2)),fr2
 209         lddfi           @(gr8,#__FPMEDIA_FR( 4)),fr4
 210         lddfi           @(gr8,#__FPMEDIA_FR( 6)),fr6
 211         lddfi           @(gr8,#__FPMEDIA_FR( 8)),fr8
 212         lddfi           @(gr8,#__FPMEDIA_FR(10)),fr10
 213         lddfi           @(gr8,#__FPMEDIA_FR(12)),fr12
 214         lddfi           @(gr8,#__FPMEDIA_FR(14)),fr14
 215         lddfi           @(gr8,#__FPMEDIA_FR(16)),fr16
 216         lddfi           @(gr8,#__FPMEDIA_FR(18)),fr18
 217         lddfi           @(gr8,#__FPMEDIA_FR(20)),fr20
 218         lddfi           @(gr8,#__FPMEDIA_FR(22)),fr22
 219         lddfi           @(gr8,#__FPMEDIA_FR(24)),fr24
 220         lddfi           @(gr8,#__FPMEDIA_FR(26)),fr26
 221         lddfi           @(gr8,#__FPMEDIA_FR(28)),fr28
 222         lddfi.p         @(gr8,#__FPMEDIA_FR(30)),fr30
 223
 224         # some CPU's have FR32-FR63
 225         setlos          #HSR0_FRHE,gr4
 226         andcc           gr6,gr4,gr0,icc0
 227         beq             icc0,#1,__restore_skip_fr32_fr63
 228
 229         lddfi           @(gr8,#__FPMEDIA_FR(32)),fr32
 230         lddfi           @(gr8,#__FPMEDIA_FR(34)),fr34
 231         lddfi           @(gr8,#__FPMEDIA_FR(36)),fr36
 232         lddfi           @(gr8,#__FPMEDIA_FR(38)),fr38
 233         lddfi           @(gr8,#__FPMEDIA_FR(40)),fr40
 234         lddfi           @(gr8,#__FPMEDIA_FR(42)),fr42
 235         lddfi           @(gr8,#__FPMEDIA_FR(44)),fr44
 236         lddfi           @(gr8,#__FPMEDIA_FR(46)),fr46
 237         lddfi           @(gr8,#__FPMEDIA_FR(48)),fr48
 238         lddfi           @(gr8,#__FPMEDIA_FR(50)),fr50
 239         lddfi           @(gr8,#__FPMEDIA_FR(52)),fr52
 240         lddfi           @(gr8,#__FPMEDIA_FR(54)),fr54
 241         lddfi           @(gr8,#__FPMEDIA_FR(56)),fr56
 242         lddfi           @(gr8,#__FPMEDIA_FR(58)),fr58
 243         lddfi           @(gr8,#__FPMEDIA_FR(60)),fr60
 244         lddfi           @(gr8,#__FPMEDIA_FR(62)),fr62
 245 __restore_skip_fr32_fr63:
 246
 247         lddi            @(gr8,#__FPMEDIA_FNER(0)),gr4
 248         movsg           fner0,gr4
 249         movsg           fner1,gr5
 250         or.p            gr9,gr9,gr8
 251         bralr
 252
 253         # the FR451 also has ACC8-11/ACCG8-11 regs (but not 4-7...)
 254 __restore_acc_fr451:
 255         lddfi           @(gr8,#__FPMEDIA_ACC(4)),fr16
 256         lddfi           @(gr8,#__FPMEDIA_ACC(6)),fr18
 257         ldbfi           @(gr8,#__FPMEDIA_ACCG(4)),fr20
 258         ldbfi           @(gr8,#__FPMEDIA_ACCG(5)),fr21
 259         ldbfi           @(gr8,#__FPMEDIA_ACCG(6)),fr22
 260         ldbfi           @(gr8,#__FPMEDIA_ACCG(7)),fr23
 261
 262         mwtacc          fr16,acc8
 263         mwtacc          fr17,acc9
 264         mwtacc          fr18,acc10
 265         mwtacc          fr19,acc11
 266         mwtaccg         fr20,accg8
 267         mwtaccg         fr21,accg9
 268         mwtaccg         fr22,accg10
 269         mwtaccg         fr23,accg11
 270         bra             __restore_acc_cont
 271
 272         # the FR555 also has ACC4-7/ACCG4-7 regs and an FSR0 reg
 273 __restore_acc_fr555:
 274         lddfi           @(gr8,#__FPMEDIA_ACC(4)),fr16
 275         lddfi           @(gr8,#__FPMEDIA_ACC(6)),fr18
 276         ldbfi           @(gr8,#__FPMEDIA_ACCG(4)),fr20
 277         ldbfi           @(gr8,#__FPMEDIA_ACCG(5)),fr21
 278         ldbfi           @(gr8,#__FPMEDIA_ACCG(6)),fr22
 279         ldbfi           @(gr8,#__FPMEDIA_ACCG(7)),fr23
 280
 281         mnop.p
 282         mwtacc          fr16,acc4
 283         mnop.p
 284         mwtacc          fr17,acc5
 285         mnop.p
 286         mwtacc          fr18,acc6
 287         mnop.p
 288         mwtacc          fr19,acc7
 289         mnop.p
 290         mwtaccg         fr20,accg4
 291         mnop.p
 292         mwtaccg         fr21,accg5
 293         mnop.p
 294         mwtaccg         fr22,accg6
 295         mnop.p
 296         mwtaccg         fr23,accg7
 297
 298         ldi             @(gr8,#__FPMEDIA_FSR(0)),gr4
 299         movgs           gr4,fsr0
 300
 301         bra             __restore_acc_cont
 302
 303
 304 ###############################################################################
 305 #
 306 # save extra general regs and FP/Media regs
 307 # - void save_user_regs(struct user_context *target)
 308 #
 309 ###############################################################################
 310         .globl          save_user_regs
 311 save_user_regs:
 312         movsg           hsr0,gr6
 313         ori             gr6,#HSR0_GRHE|HSR0_FRLE|HSR0_FRHE,gr6
 314         movgs           gr6,hsr0
 315         movsg           hsr0,gr6
 316
 317         movsg           psr,gr7
 318         ori             gr7,#PSR_EF|PSR_EM,gr7
 319         movgs           gr7,psr
 320         movsg           psr,gr7
 321         srli            gr7,#24,gr7
 322         bar
 323
 324         movsg           fner0,gr4
 325         movsg           fner1,gr5
 326         stdi.p          gr4,@(gr8,#__FPMEDIA_FNER(0))
 327
 328         # some CPU's have GR32-GR63
 329         setlos          #HSR0_GRHE,gr4
 330         andcc           gr6,gr4,gr0,icc0
 331         beq             icc0,#1,__save_skip_gr32_gr63
 332
 333         stdi            gr32,@(gr8,#__INT_GR(32))
 334         stdi            gr34,@(gr8,#__INT_GR(34))
 335         stdi            gr36,@(gr8,#__INT_GR(36))
 336         stdi            gr38,@(gr8,#__INT_GR(38))
 337         stdi            gr40,@(gr8,#__INT_GR(40))
 338         stdi            gr42,@(gr8,#__INT_GR(42))
 339         stdi            gr44,@(gr8,#__INT_GR(44))
 340         stdi            gr46,@(gr8,#__INT_GR(46))
 341         stdi            gr48,@(gr8,#__INT_GR(48))
 342         stdi            gr50,@(gr8,#__INT_GR(50))
 343         stdi            gr52,@(gr8,#__INT_GR(52))
 344         stdi            gr54,@(gr8,#__INT_GR(54))
 345         stdi            gr56,@(gr8,#__INT_GR(56))
 346         stdi            gr58,@(gr8,#__INT_GR(58))
 347         stdi            gr60,@(gr8,#__INT_GR(60))
 348         stdi            gr62,@(gr8,#__INT_GR(62))
 349 __save_skip_gr32_gr63:
 350
 351         # all CPU's have FR0-FR31
 352         stdfi           fr0 ,@(gr8,#__FPMEDIA_FR( 0))
 353         stdfi           fr2 ,@(gr8,#__FPMEDIA_FR( 2))
 354         stdfi           fr4 ,@(gr8,#__FPMEDIA_FR( 4))
 355         stdfi           fr6 ,@(gr8,#__FPMEDIA_FR( 6))
 356         stdfi           fr8 ,@(gr8,#__FPMEDIA_FR( 8))
 357         stdfi           fr10,@(gr8,#__FPMEDIA_FR(10))
 358         stdfi           fr12,@(gr8,#__FPMEDIA_FR(12))
 359         stdfi           fr14,@(gr8,#__FPMEDIA_FR(14))
 360         stdfi           fr16,@(gr8,#__FPMEDIA_FR(16))
 361         stdfi           fr18,@(gr8,#__FPMEDIA_FR(18))
 362         stdfi           fr20,@(gr8,#__FPMEDIA_FR(20))
 363         stdfi           fr22,@(gr8,#__FPMEDIA_FR(22))
 364         stdfi           fr24,@(gr8,#__FPMEDIA_FR(24))
 365         stdfi           fr26,@(gr8,#__FPMEDIA_FR(26))
 366         stdfi           fr28,@(gr8,#__FPMEDIA_FR(28))
 367         stdfi.p         fr30,@(gr8,#__FPMEDIA_FR(30))
 368
 369         # some CPU's have FR32-FR63
 370         setlos          #HSR0_FRHE,gr4
 371         andcc           gr6,gr4,gr0,icc0
 372         beq             icc0,#1,__save_skip_fr32_fr63
 373
 374         stdfi           fr32,@(gr8,#__FPMEDIA_FR(32))
 375         stdfi           fr34,@(gr8,#__FPMEDIA_FR(34))
 376         stdfi           fr36,@(gr8,#__FPMEDIA_FR(36))
 377         stdfi           fr38,@(gr8,#__FPMEDIA_FR(38))
 378         stdfi           fr40,@(gr8,#__FPMEDIA_FR(40))
 379         stdfi           fr42,@(gr8,#__FPMEDIA_FR(42))
 380         stdfi           fr44,@(gr8,#__FPMEDIA_FR(44))
 381         stdfi           fr46,@(gr8,#__FPMEDIA_FR(46))
 382         stdfi           fr48,@(gr8,#__FPMEDIA_FR(48))
 383         stdfi           fr50,@(gr8,#__FPMEDIA_FR(50))
 384         stdfi           fr52,@(gr8,#__FPMEDIA_FR(52))
 385         stdfi           fr54,@(gr8,#__FPMEDIA_FR(54))
 386         stdfi           fr56,@(gr8,#__FPMEDIA_FR(56))
 387         stdfi           fr58,@(gr8,#__FPMEDIA_FR(58))
 388         stdfi           fr60,@(gr8,#__FPMEDIA_FR(60))
 389         stdfi           fr62,@(gr8,#__FPMEDIA_FR(62))
 390 __save_skip_fr32_fr63:
 391
 392         mrdacc          acc0 ,fr4
 393         mrdacc          acc1 ,fr5
 394
 395         stdfi.p         fr4 ,@(gr8,#__FPMEDIA_ACC(0))
 396
 397         mrdacc          acc2 ,fr6
 398         mrdacc          acc3 ,fr7
 399
 400         stdfi.p         fr6 ,@(gr8,#__FPMEDIA_ACC(2))
 401
 402         mrdaccg         accg0,fr4
 403         stbfi.p         fr4 ,@(gr8,#__FPMEDIA_ACCG(0))
 404
 405         mrdaccg         accg1,fr5
 406         stbfi.p         fr5 ,@(gr8,#__FPMEDIA_ACCG(1))
 407
 408         mrdaccg         accg2,fr6
 409         stbfi.p         fr6 ,@(gr8,#__FPMEDIA_ACCG(2))
 410
 411         mrdaccg         accg3,fr7
 412         stbfi           fr7 ,@(gr8,#__FPMEDIA_ACCG(3))
 413
 414         movsg           msr0 ,gr4
 415         movsg           msr1 ,gr5
 416
 417         stdi            gr4 ,@(gr8,#__FPMEDIA_MSR(0))
 418
 419         # some CPUs have extra ACCx and ACCGx regs and maybe FSRx regs
 420         subicc.p        gr7,#0x50,gr0,icc0
 421         subicc          gr7,#0x31,gr0,icc1
 422         beq             icc0,#0,__save_acc_fr451
 423         beq             icc1,#0,__save_acc_fr555
 424 __save_acc_cont:
 425
 426         lddfi           @(gr8,#__FPMEDIA_FR(4)),fr4
 427         lddfi.p         @(gr8,#__FPMEDIA_FR(6)),fr6
 428         bralr
 429
 430         # the FR451 also has ACC8-11/ACCG8-11 regs (but not 4-7...)
 431 __save_acc_fr451:
 432         mrdacc          acc8 ,fr4
 433         mrdacc          acc9 ,fr5
 434
 435         stdfi.p         fr4 ,@(gr8,#__FPMEDIA_ACC(4))
 436
 437         mrdacc          acc10,fr6
 438         mrdacc          acc11,fr7
 439
 440         stdfi.p         fr6 ,@(gr8,#__FPMEDIA_ACC(6))
 441
 442         mrdaccg         accg8,fr4
 443         stbfi.p         fr4 ,@(gr8,#__FPMEDIA_ACCG(4))
 444
 445         mrdaccg         accg9,fr5
 446         stbfi.p         fr5 ,@(gr8,#__FPMEDIA_ACCG(5))
 447
 448         mrdaccg         accg10,fr6
 449         stbfi.p         fr6 ,@(gr8,#__FPMEDIA_ACCG(6))
 450
 451         mrdaccg         accg11,fr7
 452         stbfi           fr7 ,@(gr8,#__FPMEDIA_ACCG(7))
 453         bra             __save_acc_cont
 454
 455         # the FR555 also has ACC4-7/ACCG4-7 regs and an FSR0 reg
 456 __save_acc_fr555:
 457         mnop.p
 458         mrdacc          acc4 ,fr4
 459         mnop.p
 460         mrdacc          acc5 ,fr5
 461
 462         stdfi           fr4 ,@(gr8,#__FPMEDIA_ACC(4))
 463
 464         mnop.p
 465         mrdacc          acc6 ,fr6
 466         mnop.p
 467         mrdacc          acc7 ,fr7
 468
 469         stdfi           fr6 ,@(gr8,#__FPMEDIA_ACC(6))
 470
 471         mnop.p
 472         mrdaccg         accg4,fr4
 473         stbfi           fr4 ,@(gr8,#__FPMEDIA_ACCG(4))
 474
 475         mnop.p
 476         mrdaccg         accg5,fr5
 477         stbfi           fr5 ,@(gr8,#__FPMEDIA_ACCG(5))
 478
 479         mnop.p
 480         mrdaccg         accg6,fr6
 481         stbfi           fr6 ,@(gr8,#__FPMEDIA_ACCG(6))
 482
 483         mnop.p
 484         mrdaccg         accg7,fr7
 485         stbfi           fr7 ,@(gr8,#__FPMEDIA_ACCG(7))
 486
 487         movsg           fsr0 ,gr4
 488         sti             gr4 ,@(gr8,#__FPMEDIA_FSR(0))
 489         bra             __save_acc_cont