arch/score/kernel/entry.S

   1 /*
   2  * arch/score/kernel/entry.S
   3  *
   4  * Score Processor version.
   5  *
   6  * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
   7  *  Chen Liqin <liqin.chen@sunplusct.com>
   8  *  Lennox Wu <lennox.wu@sunplusct.com>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, see the file COPYING, or write
  22  * to the Free Software Foundation, Inc.,
  23  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  24  */
  25
  26 #include <linux/err.h>
  27 #include <linux/init.h>
  28 #include <linux/linkage.h>
  29
  30 #include <asm/asmmacro.h>
  31 #include <asm/thread_info.h>
  32 #include <asm/unistd.h>
  33
  34 /*
  35  * disable interrupts.
  36  */
  37 .macro  disable_irq
  38         mfcr    r8, cr0
  39         srli    r8, r8, 1
  40         slli    r8, r8, 1
  41         mtcr    r8, cr0
  42         nop
  43         nop
  44         nop
  45         nop
  46         nop
  47 .endm
  48
  49 /*
  50  * enable interrupts.
  51  */
  52 .macro  enable_irq
  53         mfcr    r8, cr0
  54         ori     r8, 1
  55         mtcr    r8, cr0
  56         nop
  57         nop
  58         nop
  59         nop
  60         nop
  61 .endm
  62
  63 __INIT
  64 ENTRY(debug_exception_vector)
  65         nop!
  66         nop!
  67         nop!
  68         nop!
  69         nop!
  70         nop!
  71         nop!
  72         nop!
  73
  74 ENTRY(general_exception_vector)                 # should move to addr 0x200
  75         j       general_exception
  76         nop!
  77         nop!
  78         nop!
  79         nop!
  80         nop!
  81         nop!
  82
  83 ENTRY(interrupt_exception_vector)               # should move to addr 0x210
  84         j       interrupt_exception
  85         nop!
  86         nop!
  87         nop!
  88         nop!
  89         nop!
  90         nop!
  91
  92         .section ".text", "ax"
  93         .align  2;
  94 general_exception:
  95         mfcr    r31, cr2
  96         nop
  97         la      r30, exception_handlers
  98         andi    r31, 0x1f                       # get ecr.exc_code
  99         slli    r31, r31, 2
 100         add     r30, r30, r31
 101         lw      r30, [r30]
 102         br      r30
 103
 104 interrupt_exception:
 105         SAVE_ALL
 106         mfcr    r4, cr2
 107         nop
 108         lw      r16, [r28, TI_REGS]
 109         sw      r0, [r28, TI_REGS]
 110         la      r3, ret_from_irq
 111         srli    r4, r4, 18                      # get ecr.ip[7:2], interrupt No.
 112         mv      r5, r0
 113         j       do_IRQ
 114
 115 ENTRY(handle_nmi)                               # NMI #1
 116         SAVE_ALL
 117         mv      r4, r0
 118         la      r8, nmi_exception_handler
 119         brl     r8
 120         j       restore_all
 121
 122 ENTRY(handle_adelinsn)                          # AdEL-instruction #2
 123         SAVE_ALL
 124         mfcr    r8, cr6
 125         nop
 126         nop
 127         sw      r8, [r0, PT_EMA]
 128         mv      r4, r0
 129         la      r8, do_adelinsn
 130         brl     r8
 131         mv      r4, r0
 132         j       ret_from_exception
 133         nop
 134
 135 ENTRY(handle_ibe)                               # BusEL-instruction #5
 136         SAVE_ALL
 137         mv      r4, r0
 138         la      r8, do_be
 139         brl     r8
 140         mv      r4, r0
 141         j       ret_from_exception
 142         nop
 143
 144 ENTRY(handle_pel)                               # P-EL #6
 145         SAVE_ALL
 146         mv      r4, r0
 147         la      r8, do_pel
 148         brl     r8
 149         mv      r4, r0
 150         j       ret_from_exception
 151         nop
 152
 153 ENTRY(handle_ccu)                               # CCU #8
 154         SAVE_ALL
 155         mv      r4, r0
 156         la      r8, do_ccu
 157         brl     r8
 158         mv      r4, r0
 159         j       ret_from_exception
 160         nop
 161
 162 ENTRY(handle_ri)                                # RI #9
 163         SAVE_ALL
 164         mv      r4, r0
 165         la      r8, do_ri
 166         brl     r8
 167         mv      r4, r0
 168         j       ret_from_exception
 169         nop
 170
 171 ENTRY(handle_tr)                                # Trap #10
 172         SAVE_ALL
 173         mv      r4, r0
 174         la      r8, do_tr
 175         brl     r8
 176         mv      r4, r0
 177         j       ret_from_exception
 178         nop
 179
 180 ENTRY(handle_adedata)                           # AdES-instruction #12
 181         SAVE_ALL
 182         mfcr    r8, cr6
 183         nop
 184         nop
 185         sw      r8, [r0, PT_EMA]
 186         mv      r4, r0
 187         la      r8, do_adedata
 188         brl     r8
 189         mv      r4, r0
 190         j       ret_from_exception
 191         nop
 192
 193 ENTRY(handle_cee)                               # CeE #16
 194         SAVE_ALL
 195         mv      r4, r0
 196         la      r8, do_cee
 197         brl     r8
 198         mv      r4, r0
 199         j       ret_from_exception
 200         nop
 201
 202 ENTRY(handle_cpe)                               # CpE #17
 203         SAVE_ALL
 204         mv      r4, r0
 205         la      r8, do_cpe
 206         brl     r8
 207         mv      r4, r0
 208         j       ret_from_exception
 209         nop
 210
 211 ENTRY(handle_dbe)                               # BusEL-data #18
 212         SAVE_ALL
 213         mv      r4, r0
 214         la      r8, do_be
 215         brl     r8
 216         mv      r4, r0
 217         j       ret_from_exception
 218         nop
 219
 220 ENTRY(handle_reserved)                          # others
 221         SAVE_ALL
 222         mv      r4, r0
 223         la      r8, do_reserved
 224         brl     r8
 225         mv      r4, r0
 226         j       ret_from_exception
 227         nop
 228
 229 #ifndef CONFIG_PREEMPT
 230 #define resume_kernel   restore_all
 231 #else
 232 #define __ret_from_irq  ret_from_exception
 233 #endif
 234
 235         .align  2
 236 #ifndef CONFIG_PREEMPT
 237 ENTRY(ret_from_exception)
 238         disable_irq                     # preempt stop
 239         nop
 240         j       __ret_from_irq
 241         nop
 242 #endif
 243
 244 ENTRY(ret_from_irq)
 245         sw      r16, [r28, TI_REGS]
 246
 247 ENTRY(__ret_from_irq)
 248         lw      r8, [r0, PT_PSR]        # returning to kernel mode?
 249         andri.c r8, r8, KU_USER
 250         beq     resume_kernel
 251
 252 resume_userspace:
 253         disable_irq
 254         lw      r6, [r28, TI_FLAGS]     # current->work
 255         li      r8, _TIF_WORK_MASK
 256         and.c   r8, r8, r6              # ignoring syscall_trace
 257         bne     work_pending
 258         nop
 259         j       restore_all
 260         nop
 261
 262 #ifdef CONFIG_PREEMPT
 263 resume_kernel:
 264         disable_irq
 265         lw      r8, [r28, TI_PRE_COUNT]
 266         cmpz.c  r8
 267         bne     r8, restore_all
 268 need_resched:
 269         lw      r8, [r28, TI_FLAGS]
 270         andri.c r9, r8, _TIF_NEED_RESCHED
 271         beq     restore_all
 272         lw      r8, [r28, PT_PSR]               # Interrupts off?
 273         andri.c r8, r8, 1
 274         beq     restore_all
 275         bl      preempt_schedule_irq
 276         nop
 277         j       need_resched
 278         nop
 279 #endif
 280
 281 ENTRY(ret_from_kernel_thread)
 282         bl      schedule_tail                   # r4=struct task_struct *prev
 283         nop
 284         mv      r4, r13
 285         brl     r12
 286         j       syscall_exit
 287
 288 ENTRY(ret_from_fork)
 289         bl      schedule_tail                   # r4=struct task_struct *prev
 290
 291 ENTRY(syscall_exit)
 292         nop
 293         disable_irq
 294         lw      r6, [r28, TI_FLAGS]             # current->work
 295         li      r8, _TIF_WORK_MASK
 296         and.c   r8, r6, r8
 297         bne     syscall_exit_work
 298
 299 ENTRY(restore_all)                                      # restore full frame
 300         RESTORE_ALL_AND_RET
 301
 302 work_pending:
 303         andri.c r8, r6, _TIF_NEED_RESCHED # r6 is preloaded with TI_FLAGS
 304         beq     work_notifysig
 305 work_resched:
 306         bl      schedule
 307         nop
 308         disable_irq
 309         lw      r6, [r28, TI_FLAGS]
 310         li      r8, _TIF_WORK_MASK
 311         and.c   r8, r6, r8      # is there any work to be done
 312                                 # other than syscall tracing?
 313         beq     restore_all
 314         andri.c r8, r6, _TIF_NEED_RESCHED
 315         bne     work_resched
 316
 317 work_notifysig:
 318         mv      r4, r0
 319         li      r5, 0
 320         bl      do_notify_resume        # r6 already loaded
 321         nop
 322         j       resume_userspace
 323         nop
 324
 325 ENTRY(syscall_exit_work)
 326         li      r8, _TIF_SYSCALL_TRACE
 327         and.c   r8, r8, r6              # r6 is preloaded with TI_FLAGS
 328         beq     work_pending            # trace bit set?
 329         nop
 330         enable_irq
 331         mv      r4, r0
 332         li      r5, 1
 333         bl      do_syscall_trace
 334         nop
 335         b       resume_userspace
 336         nop
 337
 338 .macro  save_context    reg
 339         sw      r12, [\reg, THREAD_REG12];
 340         sw      r13, [\reg, THREAD_REG13];
 341         sw      r14, [\reg, THREAD_REG14];
 342         sw      r15, [\reg, THREAD_REG15];
 343         sw      r16, [\reg, THREAD_REG16];
 344         sw      r17, [\reg, THREAD_REG17];
 345         sw      r18, [\reg, THREAD_REG18];
 346         sw      r19, [\reg, THREAD_REG19];
 347         sw      r20, [\reg, THREAD_REG20];
 348         sw      r21, [\reg, THREAD_REG21];
 349         sw      r29, [\reg, THREAD_REG29];
 350         sw      r2, [\reg, THREAD_REG2];
 351         sw      r0, [\reg, THREAD_REG0]
 352 .endm
 353
 354 .macro  restore_context reg
 355         lw      r12, [\reg, THREAD_REG12];
 356         lw      r13, [\reg, THREAD_REG13];
 357         lw      r14, [\reg, THREAD_REG14];
 358         lw      r15, [\reg, THREAD_REG15];
 359         lw      r16, [\reg, THREAD_REG16];
 360         lw      r17, [\reg, THREAD_REG17];
 361         lw      r18, [\reg, THREAD_REG18];
 362         lw      r19, [\reg, THREAD_REG19];
 363         lw      r20, [\reg, THREAD_REG20];
 364         lw      r21, [\reg, THREAD_REG21];
 365         lw      r29, [\reg, THREAD_REG29];
 366         lw      r0, [\reg, THREAD_REG0];
 367         lw      r2, [\reg, THREAD_REG2];
 368         lw      r3, [\reg, THREAD_REG3]
 369 .endm
 370
 371 /*
 372  * task_struct *resume(task_struct *prev, task_struct *next,
 373  *                      struct thread_info *next_ti)
 374  */
 375 ENTRY(resume)
 376         mfcr    r9, cr0
 377         nop
 378         nop
 379         sw      r9, [r4, THREAD_PSR]
 380         save_context    r4
 381         sw      r3, [r4, THREAD_REG3]
 382
 383         mv      r28, r6
 384         restore_context r5
 385         mv      r8, r6
 386         addi    r8, KERNEL_STACK_SIZE
 387         subi    r8, 32
 388         la      r9, kernelsp;
 389         sw      r8, [r9];
 390
 391         mfcr    r9, cr0
 392         ldis    r7, 0x00ff
 393         nop
 394         and     r9, r9, r7
 395         lw      r6, [r5, THREAD_PSR]
 396         not     r7, r7
 397         and     r6, r6, r7
 398         or      r6, r6, r9
 399         mtcr    r6, cr0
 400         nop; nop; nop; nop; nop
 401         br      r3
 402
 403 ENTRY(handle_sys)
 404         SAVE_ALL
 405         sw      r8, [r0, 16]            # argument 5 from user r8
 406         sw      r9, [r0, 20]            # argument 6 from user r9
 407         enable_irq
 408
 409         sw      r4, [r0, PT_ORIG_R4]    #for restart syscall
 410         sw      r7, [r0, PT_ORIG_R7]    #for restart syscall
 411         sw      r27, [r0, PT_IS_SYSCALL] # it from syscall
 412
 413         lw      r9, [r0, PT_EPC]        # skip syscall on return
 414         addi    r9, 4
 415         sw      r9, [r0, PT_EPC]
 416
 417         cmpi.c  r27, __NR_syscalls      # check syscall number
 418         bgeu    illegal_syscall
 419
 420         slli    r8, r27, 2              # get syscall routine
 421         la      r11, sys_call_table
 422         add     r11, r11, r8
 423         lw      r10, [r11]              # get syscall entry
 424
 425         cmpz.c  r10
 426         beq     illegal_syscall
 427
 428         lw      r8, [r28, TI_FLAGS]
 429         li      r9, _TIF_SYSCALL_TRACE
 430         and.c   r8, r8, r9
 431         bne     syscall_trace_entry
 432
 433         brl     r10                     # Do The Real system call
 434
 435         cmpi.c  r4, 0
 436         blt     1f
 437         ldi     r8, 0
 438         sw      r8, [r0, PT_R7]
 439         b 2f
 440 1:
 441         cmpi.c  r4, -MAX_ERRNO - 1
 442         ble     2f
 443         ldi     r8, 0x1;
 444         sw      r8, [r0, PT_R7]
 445         neg     r4, r4
 446 2:
 447         sw      r4, [r0, PT_R4]         # save result
 448
 449 syscall_return:
 450         disable_irq
 451         lw      r6, [r28, TI_FLAGS]     # current->work
 452         li      r8, _TIF_WORK_MASK
 453         and.c   r8, r6, r8
 454         bne     syscall_return_work
 455         j       restore_all
 456
 457 syscall_return_work:
 458         j       syscall_exit_work
 459
 460 syscall_trace_entry:
 461         mv      r16, r10
 462         mv      r4, r0
 463         li      r5, 0
 464         bl      do_syscall_trace
 465
 466         mv      r8, r16
 467         lw      r4, [r0, PT_R4]         # Restore argument registers
 468         lw      r5, [r0, PT_R5]
 469         lw      r6, [r0, PT_R6]
 470         lw      r7, [r0, PT_R7]
 471         brl     r8
 472
 473         li      r8, -MAX_ERRNO - 1
 474         sw      r8, [r0, PT_R7]         # set error flag
 475
 476         neg     r4, r4                  # error
 477         sw      r4, [r0, PT_R0]         # set flag for syscall
 478                                         # restarting
 479 1:      sw      r4, [r0, PT_R2]         # result
 480         j       syscall_exit
 481
 482 illegal_syscall:
 483         ldi     r4, -ENOSYS             # error
 484         sw      r4, [r0, PT_ORIG_R4]
 485         sw      r4, [r0, PT_R4]
 486         ldi     r9, 1                   # set error flag
 487         sw      r9, [r0, PT_R7]
 488         j       syscall_return
 489
 490 ENTRY(sys_rt_sigreturn)
 491         mv      r4, r0
 492         la      r8, score_rt_sigreturn
 493         br      r8