arch/cris/arch-v10/kernel/entry.S

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  *  linux/arch/cris/entry.S
   4  *
   5  *  Copyright (C) 2000, 2001, 2002 Axis Communications AB
   6  *
   7  *  Authors:    Bjorn Wesen (bjornw@axis.com)
   8  */
   9
  10 /*
  11  * entry.S contains the system-call and fault low-level handling routines.
  12  *
  13  * NOTE: This code handles signal-recognition, which happens every time
  14  * after a timer-interrupt and after each system call.
  15  *
  16  * Stack layout in 'ret_from_system_call':
  17  *      ptrace needs to have all regs on the stack.
  18  *      if the order here is changed, it needs to be
  19  *      updated in fork.c:copy_process, signal.c:do_signal,
  20  *      ptrace.c and ptrace.h
  21  *
  22  */
  23
  24 #include <linux/linkage.h>
  25 #include <linux/sys.h>
  26 #include <asm/unistd.h>
  27 #include <arch/sv_addr_ag.h>
  28 #include <asm/errno.h>
  29 #include <asm/thread_info.h>
  30 #include <asm/asm-offsets.h>
  31 #include <asm/page.h>
  32 #include <asm/pgtable.h>
  33
  34         ;; functions exported from this file
  35
  36         .globl system_call
  37         .globl ret_from_intr
  38         .globl ret_from_fork
  39         .globl ret_from_kernel_thread
  40         .globl resume
  41         .globl multiple_interrupt
  42         .globl hwbreakpoint
  43         .globl IRQ1_interrupt
  44         .globl spurious_interrupt
  45         .globl hw_bp_trigs
  46         .globl mmu_bus_fault
  47         .globl do_sigtrap
  48         .globl gdb_handle_breakpoint
  49         .globl sys_call_table
  50
  51         ;; below are various parts of system_call which are not in the fast-path
  52
  53 #ifdef CONFIG_PREEMPT
  54         ; Check if preemptive kernel scheduling should be done
  55 _resume_kernel:
  56         di
  57         ; Load current task struct
  58         movs.w  -8192, $r0      ;  THREAD_SIZE = 8192
  59         and.d   $sp, $r0
  60         move.d  [$r0+TI_preempt_count], $r10    ;  Preemption disabled?
  61         bne     _Rexit
  62         nop
  63 _need_resched:
  64         move.d  [$r0+TI_flags], $r10
  65         btstq   TIF_NEED_RESCHED, $r10  ; Check if need_resched is set
  66         bpl     _Rexit
  67         nop
  68         ; Ok, lets's do some preemptive kernel scheduling
  69         jsr     preempt_schedule_irq
  70         ; Load new task struct
  71         movs.w  -8192, $r0      ;  THREAD_SIZE = 8192
  72         and.d   $sp, $r0
  73         ; One more time (with new task)
  74         ba      _need_resched
  75         nop
  76 #else
  77 #define _resume_kernel _Rexit
  78 #endif
  79
  80         ; Called at exit from fork. schedule_tail must be called to drop
  81         ; spinlock if CONFIG_PREEMPT
  82 ret_from_fork:
  83         jsr schedule_tail
  84         ba  ret_from_sys_call
  85         nop
  86
  87 ret_from_kernel_thread:
  88         jsr schedule_tail
  89         move.d  $r2, $r10       ; argument is here
  90         jsr     $r1             ; call the payload
  91         moveq   0, $r9          ; no syscall restarts, TYVM...
  92         ba  ret_from_sys_call
  93
  94 ret_from_intr:
  95         ;; check for resched if preemptive kernel or if we're going back to user-mode
  96         ;; this test matches the user_regs(regs) macro
  97         ;; we cannot simply test $dccr, because that does not necessarily
  98         ;; reflect what mode we'll return into.
  99
 100         move.d  [$sp + PT_dccr], $r0; regs->dccr
 101         btstq   8, $r0          ; U-flag
 102         bpl     _resume_kernel
 103         ; Note that di below is in delay slot
 104
 105 _resume_userspace:
 106         di                      ; so need_resched and sigpending don't change
 107
 108         movs.w  -8192, $r0      ; THREAD_SIZE == 8192
 109         and.d   $sp, $r0
 110
 111         move.d  [$r0+TI_flags], $r10    ; current->work
 112         and.d   _TIF_WORK_MASK, $r10    ; is there any work to be done on return
 113         bne     _work_pending
 114         nop
 115         ba      _Rexit
 116         nop
 117
 118         ;; The system_call is called by a BREAK instruction, which works like
 119         ;; an interrupt call but it stores the return PC in BRP instead of IRP.
 120         ;; Since we dont really want to have two epilogues (one for system calls
 121         ;; and one for interrupts) we push the contents of BRP instead of IRP in the
 122         ;; system call prologue, to make it look like an ordinary interrupt on the
 123         ;; stackframe.
 124         ;;
 125         ;; Since we can't have system calls inside interrupts, it should not matter
 126         ;; that we don't stack IRP.
 127         ;;
 128         ;; In r9 we have the wanted syscall number. Arguments come in r10,r11,r12,r13,mof,srp
 129         ;;
 130         ;; This function looks on the _surface_ like spaghetti programming, but it's
 131         ;; really designed so that the fast-path does not force cache-loading of non-used
 132         ;; instructions. Only the non-common cases cause the outlined code to run..
 133
 134 system_call:
 135         ;; stack-frame similar to the irq heads, which is reversed in ret_from_sys_call
 136         move    $brp,[$sp=$sp-16]; instruction pointer and room for a fake SBFS frame
 137         push    $srp
 138         push    $dccr
 139         push    $mof
 140         subq    14*4, $sp               ; make room for r0-r13
 141         movem   $r13, [$sp]     ; push r0-r13
 142         push    $r10            ; push orig_r10
 143         clear.d [$sp=$sp-4]     ; frametype == 0, normal stackframe
 144
 145         movs.w  -ENOSYS, $r0
 146         move.d  $r0, [$sp+PT_r10]       ; put the default return value in r10 in the frame
 147
 148         ;; check if this process is syscall-traced
 149
 150         movs.w  -8192, $r0      ; THREAD_SIZE == 8192
 151         and.d   $sp, $r0
 152
 153         move.d  [$r0+TI_flags], $r0
 154         btstq   TIF_SYSCALL_TRACE, $r0
 155         bmi     _syscall_trace_entry
 156         nop
 157
 158 _syscall_traced:
 159
 160         ;; check for sanity in the requested syscall number
 161
 162         cmpu.w  NR_syscalls, $r9
 163         bcc     ret_from_sys_call
 164         lslq    2, $r9          ;  multiply by 4, in the delay slot
 165
 166         ;; as a bonus 7th parameter, we give the location on the stack
 167         ;; of the register structure itself. some syscalls need this.
 168
 169         push    $sp
 170
 171         ;; the parameter carrying registers r10, r11, r12 and 13 are intact.
 172         ;; the fifth and sixth parameters (if any) was in mof and srp
 173         ;; respectively, and we need to put them on the stack.
 174
 175         push    $srp
 176         push    $mof
 177
 178         jsr     [$r9+sys_call_table]    ; actually do the system call
 179         addq    3*4, $sp                ; pop the mof, srp and regs parameters
 180         move.d  $r10, [$sp+PT_r10]      ; save the return value
 181
 182         moveq   1, $r9          ; "parameter" to ret_from_sys_call to show it was a sys call
 183
 184         ;; fall through into ret_from_sys_call to return
 185
 186 ret_from_sys_call:
 187         ;; r9 is a parameter - if >=1 we came from a syscall, if 0, from an irq
 188
 189         ;; get the current task-struct pointer (see top for defs)
 190
 191         movs.w  -8192, $r0      ; THREAD_SIZE == 8192
 192         and.d   $sp, $r0
 193
 194         di                      ; make sure need_resched and sigpending don't change
 195         move.d  [$r0+TI_flags],$r1
 196         and.d   _TIF_ALLWORK_MASK, $r1
 197         bne     _syscall_exit_work
 198         nop
 199
 200 _Rexit:
 201         ;; this epilogue MUST match the prologues in multiple_interrupt, irq.h and ptregs.h
 202         pop     $r10            ; frametype
 203         bne     _RBFexit        ; was not CRIS_FRAME_NORMAL, handle otherwise
 204         addq    4, $sp          ; skip orig_r10, in delayslot
 205         movem   [$sp+], $r13    ; registers r0-r13
 206         pop     $mof            ; multiply overflow register
 207         pop     $dccr           ; condition codes
 208         pop     $srp            ; subroutine return pointer
 209         ;; now we have a 4-word SBFS frame which we do not want to restore
 210         ;; using RBF since it was not stacked with SBFS. instead we would like to
 211         ;; just get the PC value to restart it with, and skip the rest of
 212         ;; the frame.
 213         ;; Also notice that it's important to use instructions here that
 214         ;; keep the interrupts disabled (since we've already popped DCCR)
 215         move    [$sp=$sp+16], $p8; pop the SBFS frame from the sp
 216         jmpu    [$sp-16]        ; return through the irp field in the sbfs frame
 217
 218 _RBFexit:
 219         movem   [$sp+], $r13    ; registers r0-r13, in delay slot
 220         pop     $mof            ; multiply overflow register
 221         pop     $dccr           ; condition codes
 222         pop     $srp            ; subroutine return pointer
 223         rbf     [$sp+]          ; return by popping the CPU status
 224
 225         ;; We get here after doing a syscall if extra work might need to be done
 226         ;; perform syscall exit tracing if needed
 227
 228 _syscall_exit_work:
 229         ;; $r0 contains current at this point and irq's are disabled
 230
 231         move.d  [$r0+TI_flags], $r1
 232         btstq   TIF_SYSCALL_TRACE, $r1
 233         bpl     _work_pending
 234         nop
 235
 236         ei
 237
 238         move.d  $r9, $r1        ; preserve r9
 239         jsr     do_syscall_trace
 240         move.d  $r1, $r9
 241
 242         ba      _resume_userspace
 243         nop
 244
 245 _work_pending:
 246         move.d  [$r0+TI_flags], $r1
 247         btstq   TIF_NEED_RESCHED, $r1
 248         bpl     _work_notifysig ; was neither trace nor sched, must be signal/notify
 249         nop
 250
 251 _work_resched:
 252         move.d  $r9, $r1        ; preserve r9
 253         jsr     schedule
 254         move.d  $r1, $r9
 255         di
 256
 257         move.d  [$r0+TI_flags], $r1
 258         and.d   _TIF_WORK_MASK, $r1; ignore the syscall trace counter
 259         beq     _Rexit
 260         nop
 261         btstq   TIF_NEED_RESCHED, $r1
 262         bmi     _work_resched   ; current->work.need_resched
 263         nop
 264
 265 _work_notifysig:
 266         ;; deal with pending signals and notify-resume requests
 267
 268         move.d  $r9, $r10       ; do_notify_resume syscall/irq param
 269         move.d  $sp, $r11       ; the regs param
 270         move.d  $r1, $r12       ; the thread_info_flags parameter
 271         jsr     do_notify_resume
 272
 273         ba _Rexit
 274         nop
 275
 276         ;; We get here as a sidetrack when we've entered a syscall with the
 277         ;; trace-bit set. We need to call do_syscall_trace and then continue
 278         ;; with the call.
 279
 280 _syscall_trace_entry:
 281         ;; PT_r10 in the frame contains -ENOSYS as required, at this point
 282
 283         jsr     do_syscall_trace
 284
 285         ;; now re-enter the syscall code to do the syscall itself
 286         ;; we need to restore $r9 here to contain the wanted syscall, and
 287         ;; the other parameter-bearing registers
 288
 289         move.d  [$sp+PT_r9], $r9
 290         move.d  [$sp+PT_orig_r10], $r10  ; PT_r10 is already filled with -ENOSYS.
 291         move.d  [$sp+PT_r11],      $r11
 292         move.d  [$sp+PT_r12],      $r12
 293         move.d  [$sp+PT_r13],      $r13
 294         move    [$sp+PT_mof],      $mof
 295         move    [$sp+PT_srp],      $srp
 296
 297         ba      _syscall_traced
 298         nop
 299
 300         ;; resume performs the actual task-switching, by switching stack pointers
 301         ;; input arguments: r10 = prev, r11 = next, r12 = thread offset in task struct
 302         ;; returns old current in r10
 303         ;;
 304         ;; TODO:  see the i386 version. The switch_to which calls resume in our version
 305         ;;        could really be an inline asm of this.
 306
 307 resume:
 308         push    $srp                     ; we keep the old/new PC on the stack
 309         add.d   $r12, $r10               ; r10 = current tasks tss
 310         move    $dccr, [$r10+THREAD_dccr]; save irq enable state
 311         di
 312
 313         move    $usp, [$r10+ THREAD_usp] ; save user-mode stackpointer
 314
 315         ;; See copy_thread for the reason why register R9 is saved.
 316         subq    10*4, $sp
 317         movem   $r9, [$sp]               ; save non-scratch registers and R9.
 318
 319         move.d  $sp, [$r10+THREAD_ksp]   ; save the kernel stack pointer for the old task
 320         move.d  $sp, $r10                ; return last running task in r10
 321         and.d   -8192, $r10              ; get thread_info from stackpointer
 322         move.d  [$r10+TI_task], $r10     ; get task
 323         add.d   $r12, $r11               ; find the new tasks tss
 324         move.d  [$r11+THREAD_ksp], $sp   ; switch into the new stackframe by restoring kernel sp
 325
 326         movem   [$sp+], $r9              ; restore non-scratch registers and R9.
 327
 328         move    [$r11+THREAD_usp], $usp ; restore user-mode stackpointer
 329
 330         move    [$r11+THREAD_dccr], $dccr ; restore irq enable status
 331         jump    [$sp+]                   ; restore PC
 332
 333         ;; This is the MMU bus fault handler.
 334         ;; It needs to stack the CPU status and overall is different
 335         ;; from the other interrupt handlers.
 336
 337 mmu_bus_fault:
 338         ;; For refills we try to do a quick page table lookup. If it is
 339         ;; a real fault we let the mm subsystem handle it.
 340
 341         ;; the first longword in the sbfs frame was the interrupted PC
 342         ;; which fits nicely with the "IRP" slot in pt_regs normally used to
 343         ;; contain the return address. used by Oops to print kernel errors.
 344         sbfs    [$sp=$sp-16]    ; push the internal CPU status
 345         push    $dccr
 346         di
 347         subq    2*4, $sp
 348         movem   $r1, [$sp]
 349         move.d  [R_MMU_CAUSE], $r1
 350         ;; ETRAX 100LX TR89 bugfix: if the second half of an unaligned
 351         ;; write causes a MMU-fault, it will not be restarted correctly.
 352         ;; This could happen if a write crosses a page-boundary and the
 353         ;; second page is not yet COW'ed or even loaded. The workaround
 354         ;; is to clear the unaligned bit in the CPU status record, so
 355         ;; that the CPU will rerun both the first and second halves of
 356         ;; the instruction. This will not have any sideeffects unless
 357         ;; the first half goes to any device or memory that can't be
 358         ;; written twice, and which is mapped through the MMU.
 359         ;;
 360         ;; We only need to do this for writes.
 361         btstq   8, $r1             ; Write access?
 362         bpl     1f
 363         nop
 364         move.d  [$sp+16], $r0      ; Clear unaligned bit in csrinstr
 365         and.d   ~(1<<5), $r0
 366         move.d  $r0, [$sp+16]
 367 1:      btstq   12, $r1            ; Refill?
 368         bpl     2f
 369         lsrq    24, $r1     ; Get PGD index (bit 24-31)
 370         move.d  [current_pgd], $r0 ; PGD for the current process
 371         move.d  [$r0+$r1.d], $r0   ; Get PMD
 372         beq     2f
 373         nop
 374         and.w   PAGE_MASK, $r0     ; Remove PMD flags
 375         move.d  [R_MMU_CAUSE], $r1
 376         lsrq    PAGE_SHIFT, $r1
 377         and.d   0x7ff, $r1         ; Get PTE index into PGD (bit 13-23)
 378         move.d  [$r0+$r1.d], $r1   ; Get PTE
 379         beq     2f
 380         nop
 381         ;; Store in TLB
 382         move.d  $r1, [R_TLB_LO]
 383         ;; Return
 384         movem   [$sp+], $r1
 385         pop     $dccr
 386         rbf     [$sp+]          ; return by popping the CPU status
 387
 388 2:      ; PMD or PTE missing, let the mm subsystem fix it up.
 389         movem   [$sp+], $r1
 390         pop     $dccr
 391
 392         ; Ok, not that easy, pass it on to the mm subsystem
 393         ; The MMU status record is now on the stack
 394         push    $srp            ; make a stackframe similar to pt_regs
 395         push    $dccr
 396         push    $mof
 397         di
 398         subq    14*4, $sp
 399         movem   $r13, [$sp]
 400         push    $r10            ; dummy orig_r10
 401         moveq   1, $r10
 402         push    $r10            ; frametype == 1, BUSFAULT frame type
 403
 404         move.d  $sp, $r10       ; pt_regs argument to handle_mmu_bus_fault
 405
 406         jsr     handle_mmu_bus_fault  ; in arch/cris/arch-v10/mm/fault.c
 407
 408         ;; now we need to return through the normal path, we cannot just
 409         ;; do the RBFexit since we might have killed off the running
 410         ;; process due to a SEGV, scheduled due to a page blocking or
 411         ;; whatever.
 412
 413         moveq   0, $r9          ; busfault is equivalent to an irq
 414
 415         ba      ret_from_intr
 416         nop
 417
 418         ;; special handlers for breakpoint and NMI
 419 hwbreakpoint:
 420         push    $dccr
 421         di
 422         push    $r10
 423         push    $r11
 424         move.d  [hw_bp_trig_ptr],$r10
 425         move    $brp,$r11
 426         move.d  $r11,[$r10+]
 427         move.d  $r10,[hw_bp_trig_ptr]
 428 1:      pop     $r11
 429         pop     $r10
 430         pop     $dccr
 431         retb
 432         nop
 433
 434 IRQ1_interrupt:
 435         ;; this prologue MUST match the one in irq.h and the struct in ptregs.h!!!
 436         move    $brp,[$sp=$sp-16]; instruction pointer and room for a fake SBFS frame
 437         push    $srp
 438         push    $dccr
 439         push    $mof
 440         di
 441         subq    14*4, $sp
 442         movem   $r13, [$sp]
 443         push    $r10            ; push orig_r10
 444         clear.d [$sp=$sp-4]     ; frametype == 0, normal frame
 445
 446         ;; If there is a glitch on the NMI pin shorter than ~100ns
 447         ;; (i.e. non-active by the time we get here) then the nmi_pin bit
 448         ;; in R_IRQ_MASK0_RD will already be cleared.  The watchdog_nmi bit
 449         ;; is cleared by us however (when feeding the watchdog), which is why
 450         ;; we use that bit to determine what brought us here.
 451
 452         move.d  [R_IRQ_MASK0_RD], $r1 ; External NMI or watchdog?
 453         and.d   (1<<30), $r1
 454         bne     wdog
 455         move.d  $sp, $r10
 456         jsr     handle_nmi
 457         setf m                  ; Enable NMI again
 458         ba      _Rexit          ; Return the standard way
 459         nop
 460 wdog:
 461 #if defined(CONFIG_ETRAX_WATCHDOG)
 462 ;; Check if we're waiting for reset to happen, as signalled by
 463 ;; hard_reset_now setting cause_of_death to a magic value.  If so, just
 464 ;; get stuck until reset happens.
 465         .comm   cause_of_death, 4       ;; Don't declare this anywhere.
 466         move.d  [cause_of_death], $r10
 467         cmp.d   0xbedead, $r10
 468 _killed_by_death:
 469         beq     _killed_by_death
 470         nop
 471
 472 ;; We'll see this in ksymoops dumps.
 473 Watchdog_bite:
 474
 475 #ifdef CONFIG_ETRAX_WATCHDOG_NICE_DOGGY
 476        ;; We just restart the watchdog here to be sure we dont get
 477        ;; hit while printing the watchdogmsg below
 478        ;; This restart is compatible with the rest of the C-code, so
 479        ;; the C-code can keep restarting the watchdog after this point.
 480        ;; The non-NICE_DOGGY code below though, disables the possibility
 481        ;; to restart since it changes the watchdog key, to avoid any
 482        ;; buggy loops etc. keeping the watchdog alive after this.
 483        jsr     reset_watchdog
 484 #else
 485
 486 ;; We need to extend the 3.3ms after the NMI at watchdog bite, so we have
 487 ;; time for an oops-dump over a 115k2 serial wire.  Another 100ms should do.
 488
 489 ;; Change the watchdog key to an arbitrary 3-bit value and restart the
 490 ;; watchdog.
 491 #define WD_INIT 2
 492         moveq     IO_FIELD (R_WATCHDOG, key, WD_INIT), $r10
 493         move.d  R_WATCHDOG, $r11
 494
 495         move.d  $r10, [$r11]
 496         moveq     IO_FIELD (R_WATCHDOG, key,                            \
 497                             IO_EXTRACT (R_WATCHDOG, key,                \
 498                                         IO_MASK (R_WATCHDOG, key))      \
 499                             ^ WD_INIT)                                  \
 500                 | IO_STATE (R_WATCHDOG, enable, start), $r10
 501         move.d  $r10, [$r11]
 502
 503 #endif
 504
 505 ;; Note that we don't do "setf m" here (or after two necessary NOPs),
 506 ;; since *not* doing that saves us from re-entrancy checks.  We don't want
 507 ;; to get here again due to possible subsequent NMIs; we want the watchdog
 508 ;; to reset us.
 509
 510         move.d  _watchdogmsg,$r10
 511         jsr     printk
 512
 513         move.d  $sp, $r10
 514         jsr     watchdog_bite_hook
 515
 516 ;; This nop is here so we see the "Watchdog_bite" label in ksymoops dumps
 517 ;; rather than "spurious_interrupt".
 518         nop
 519 ;; At this point we drop down into spurious_interrupt, which will do a
 520 ;; hard reset.
 521
 522         .section .rodata,"a"
 523 _watchdogmsg:
 524         .ascii  "Oops: bitten by watchdog\n\0"
 525         .previous
 526
 527 #endif /* CONFIG_ETRAX_WATCHDOG */
 528
 529 spurious_interrupt:
 530         di
 531         jump hard_reset_now
 532
 533         ;; this handles the case when multiple interrupts arrive at the same time
 534         ;; we jump to the first set interrupt bit in a priority fashion
 535         ;; the hardware will call the unserved interrupts after the handler finishes
 536
 537 multiple_interrupt:
 538         ;; this prologue MUST match the one in irq.h and the struct in ptregs.h!!!
 539         move    $irp,[$sp=$sp-16]; instruction pointer and room for a fake SBFS frame
 540         push    $srp
 541         push    $dccr
 542         push    $mof
 543         di
 544         subq    14*4, $sp
 545         movem   $r13, [$sp]
 546         push    $r10            ; push orig_r10
 547         clear.d [$sp=$sp-4]     ; frametype == 0, normal frame
 548
 549         move.d  $sp, $r10
 550         jsr     do_multiple_IRQ
 551
 552         jump    ret_from_intr
 553
 554 do_sigtrap:
 555         ;;
 556         ;; SIGTRAP the process that executed the break instruction.
 557         ;; Make a frame that Rexit in entry.S expects.
 558         ;;
 559         move    $brp, [$sp=$sp-16]      ; Push BRP while faking a cpu status record.
 560         push    $srp                    ; Push subroutine return pointer.
 561         push    $dccr                   ; Push condition codes.
 562         push    $mof                    ; Push multiply overflow reg.
 563         di                              ; Need to disable irq's at this point.
 564         subq    14*4, $sp               ; Make room for r0-r13.
 565         movem   $r13, [$sp]             ; Push the r0-r13 registers.
 566         push    $r10                    ; Push orig_r10.
 567         clear.d [$sp=$sp-4]             ; Frametype - this is a normal stackframe.
 568
 569         movs.w  -8192,$r9               ; THREAD_SIZE == 8192
 570         and.d   $sp, $r9
 571         move.d  [$r9+TI_task], $r10
 572         move.d  [$r10+TASK_pid], $r10   ; current->pid as arg1.
 573         moveq   5, $r11                 ; SIGTRAP as arg2.
 574         jsr     sys_kill
 575         jump    ret_from_intr           ; Use the return routine for interrupts.
 576
 577 gdb_handle_breakpoint:
 578         push    $dccr
 579         push    $r0
 580 #ifdef CONFIG_ETRAX_KGDB
 581         move    $dccr, $r0              ; U-flag not affected by previous insns.
 582         btstq   8, $r0                  ; Test the U-flag.
 583         bmi     _ugdb_handle_breakpoint ; Go to user mode debugging.
 584         nop                             ; Empty delay slot (cannot pop r0 here).
 585         pop     $r0                     ; Restore r0.
 586         ba      kgdb_handle_breakpoint  ; Go to kernel debugging.
 587         pop     $dccr                   ; Restore dccr in delay slot.
 588 #endif
 589
 590 _ugdb_handle_breakpoint:
 591         move    $brp, $r0               ; Use r0 temporarily for calculation.
 592         subq    2, $r0                  ; Set to address of previous instruction.
 593         move    $r0, $brp
 594         pop     $r0                     ; Restore r0.
 595         ba      do_sigtrap              ; SIGTRAP the offending process.
 596         pop     $dccr                   ; Restore dccr in delay slot.
 597
 598         .data
 599
 600 hw_bp_trigs:
 601         .space 64*4
 602 hw_bp_trig_ptr:
 603         .dword hw_bp_trigs
 604
 605         .section .rodata,"a"
 606 sys_call_table:
 607         .long sys_restart_syscall       /* 0 - old "setup()" system call, used for restarting */
 608         .long sys_exit
 609         .long sys_fork
 610         .long sys_read
 611         .long sys_write
 612         .long sys_open          /* 5 */
 613         .long sys_close
 614         .long sys_waitpid
 615         .long sys_creat
 616         .long sys_link
 617         .long sys_unlink        /* 10 */
 618         .long sys_execve
 619         .long sys_chdir
 620         .long sys_time
 621         .long sys_mknod
 622         .long sys_chmod         /* 15 */
 623         .long sys_lchown16
 624         .long sys_ni_syscall    /* old break syscall holder */
 625         .long sys_stat
 626         .long sys_lseek
 627         .long sys_getpid        /* 20 */
 628         .long sys_mount
 629         .long sys_oldumount
 630         .long sys_setuid16
 631         .long sys_getuid16
 632         .long sys_stime         /* 25 */
 633         .long sys_ptrace
 634         .long sys_alarm
 635         .long sys_fstat
 636         .long sys_pause
 637         .long sys_utime         /* 30 */
 638         .long sys_ni_syscall    /* old stty syscall holder */
 639         .long sys_ni_syscall    /* old gtty syscall holder */
 640         .long sys_access
 641         .long sys_nice
 642         .long sys_ni_syscall    /* 35  old ftime syscall holder */
 643         .long sys_sync
 644         .long sys_kill
 645         .long sys_rename
 646         .long sys_mkdir
 647         .long sys_rmdir         /* 40 */
 648         .long sys_dup
 649         .long sys_pipe
 650         .long sys_times
 651         .long sys_ni_syscall    /* old prof syscall holder */
 652         .long sys_brk           /* 45 */
 653         .long sys_setgid16
 654         .long sys_getgid16
 655         .long sys_signal
 656         .long sys_geteuid16
 657         .long sys_getegid16     /* 50 */
 658         .long sys_acct
 659         .long sys_umount        /* recycled never used phys( */
 660         .long sys_ni_syscall    /* old lock syscall holder */
 661         .long sys_ioctl
 662         .long sys_fcntl         /* 55 */
 663         .long sys_ni_syscall    /* old mpx syscall holder */
 664         .long sys_setpgid
 665         .long sys_ni_syscall    /* old ulimit syscall holder */
 666         .long sys_ni_syscall    /* old sys_olduname holder */
 667         .long sys_umask         /* 60 */
 668         .long sys_chroot
 669         .long sys_ustat
 670         .long sys_dup2
 671         .long sys_getppid
 672         .long sys_getpgrp       /* 65 */
 673         .long sys_setsid
 674         .long sys_sigaction
 675         .long sys_sgetmask
 676         .long sys_ssetmask
 677         .long sys_setreuid16    /* 70 */
 678         .long sys_setregid16
 679         .long sys_sigsuspend
 680         .long sys_sigpending
 681         .long sys_sethostname
 682         .long sys_setrlimit     /* 75 */
 683         .long sys_old_getrlimit
 684         .long sys_getrusage
 685         .long sys_gettimeofday
 686         .long sys_settimeofday
 687         .long sys_getgroups16   /* 80 */
 688         .long sys_setgroups16
 689         .long sys_select        /* was old_select in Linux/E100 */
 690         .long sys_symlink
 691         .long sys_lstat
 692         .long sys_readlink      /* 85 */
 693         .long sys_uselib
 694         .long sys_swapon
 695         .long sys_reboot
 696         .long sys_old_readdir
 697         .long sys_old_mmap      /* 90 */
 698         .long sys_munmap
 699         .long sys_truncate
 700         .long sys_ftruncate
 701         .long sys_fchmod
 702         .long sys_fchown16      /* 95 */
 703         .long sys_getpriority
 704         .long sys_setpriority
 705         .long sys_ni_syscall    /* old profil syscall holder */
 706         .long sys_statfs
 707         .long sys_fstatfs       /* 100 */
 708         .long sys_ni_syscall    /* sys_ioperm in i386 */
 709         .long sys_socketcall
 710         .long sys_syslog
 711         .long sys_setitimer
 712         .long sys_getitimer     /* 105 */
 713         .long sys_newstat
 714         .long sys_newlstat
 715         .long sys_newfstat
 716         .long sys_ni_syscall    /* old sys_uname holder */
 717         .long sys_ni_syscall    /* 110 */ /* sys_iopl in i386 */
 718         .long sys_vhangup
 719         .long sys_ni_syscall    /* old "idle" system call */
 720         .long sys_ni_syscall    /* vm86old in i386 */
 721         .long sys_wait4
 722         .long sys_swapoff       /* 115 */
 723         .long sys_sysinfo
 724         .long sys_ipc
 725         .long sys_fsync
 726         .long sys_sigreturn
 727         .long sys_clone         /* 120 */
 728         .long sys_setdomainname
 729         .long sys_newuname
 730         .long sys_ni_syscall    /* sys_modify_ldt */
 731         .long sys_adjtimex
 732         .long sys_mprotect      /* 125 */
 733         .long sys_sigprocmask
 734         .long sys_ni_syscall    /* old "create_module" */
 735         .long sys_init_module
 736         .long sys_delete_module
 737         .long sys_ni_syscall    /* 130: old "get_kernel_syms" */
 738         .long sys_quotactl
 739         .long sys_getpgid
 740         .long sys_fchdir
 741         .long sys_bdflush
 742         .long sys_sysfs         /* 135 */
 743         .long sys_personality
 744         .long sys_ni_syscall    /* for afs_syscall */
 745         .long sys_setfsuid16
 746         .long sys_setfsgid16
 747         .long sys_llseek        /* 140 */
 748         .long sys_getdents
 749         .long sys_select
 750         .long sys_flock
 751         .long sys_msync
 752         .long sys_readv         /* 145 */
 753         .long sys_writev
 754         .long sys_getsid
 755         .long sys_fdatasync
 756         .long sys_sysctl
 757         .long sys_mlock         /* 150 */
 758         .long sys_munlock
 759         .long sys_mlockall
 760         .long sys_munlockall
 761         .long sys_sched_setparam
 762         .long sys_sched_getparam        /* 155 */
 763         .long sys_sched_setscheduler
 764         .long sys_sched_getscheduler
 765         .long sys_sched_yield
 766         .long sys_sched_get_priority_max
 767         .long sys_sched_get_priority_min        /* 160 */
 768         .long sys_sched_rr_get_interval
 769         .long sys_nanosleep
 770         .long sys_mremap
 771         .long sys_setresuid16
 772         .long sys_getresuid16   /* 165 */
 773         .long sys_ni_syscall    /* sys_vm86 */
 774         .long sys_ni_syscall    /* Old sys_query_module */
 775         .long sys_poll
 776         .long sys_ni_syscall    /* old nfsservctl */
 777         .long sys_setresgid16   /* 170 */
 778         .long sys_getresgid16
 779         .long sys_prctl
 780         .long sys_rt_sigreturn
 781         .long sys_rt_sigaction
 782         .long sys_rt_sigprocmask        /* 175 */
 783         .long sys_rt_sigpending
 784         .long sys_rt_sigtimedwait
 785         .long sys_rt_sigqueueinfo
 786         .long sys_rt_sigsuspend
 787         .long sys_pread64       /* 180 */
 788         .long sys_pwrite64
 789         .long sys_chown16
 790         .long sys_getcwd
 791         .long sys_capget
 792         .long sys_capset        /* 185 */
 793         .long sys_sigaltstack
 794         .long sys_sendfile
 795         .long sys_ni_syscall    /* streams1 */
 796         .long sys_ni_syscall    /* streams2 */
 797         .long sys_vfork         /* 190 */
 798         .long sys_getrlimit
 799         .long sys_mmap2         /* mmap_pgoff */
 800         .long sys_truncate64
 801         .long sys_ftruncate64
 802         .long sys_stat64        /* 195 */
 803         .long sys_lstat64
 804         .long sys_fstat64
 805         .long sys_lchown
 806         .long sys_getuid
 807         .long sys_getgid        /* 200 */
 808         .long sys_geteuid
 809         .long sys_getegid
 810         .long sys_setreuid
 811         .long sys_setregid
 812         .long sys_getgroups     /* 205 */
 813         .long sys_setgroups
 814         .long sys_fchown
 815         .long sys_setresuid
 816         .long sys_getresuid
 817         .long sys_setresgid     /* 210 */
 818         .long sys_getresgid
 819         .long sys_chown
 820         .long sys_setuid
 821         .long sys_setgid
 822         .long sys_setfsuid      /* 215 */
 823         .long sys_setfsgid
 824         .long sys_pivot_root
 825         .long sys_mincore
 826         .long sys_madvise
 827         .long sys_getdents64    /* 220 */
 828         .long sys_fcntl64
 829         .long sys_ni_syscall    /* reserved for TUX */
 830         .long sys_ni_syscall
 831         .long sys_gettid
 832         .long sys_readahead     /* 225 */
 833         .long sys_setxattr
 834         .long sys_lsetxattr
 835         .long sys_fsetxattr
 836         .long sys_getxattr
 837         .long sys_lgetxattr     /* 230 */
 838         .long sys_fgetxattr
 839         .long sys_listxattr
 840         .long sys_llistxattr
 841         .long sys_flistxattr
 842         .long sys_removexattr   /* 235 */
 843         .long sys_lremovexattr
 844         .long sys_fremovexattr
 845         .long sys_tkill
 846         .long sys_sendfile64
 847         .long sys_futex         /* 240 */
 848         .long sys_sched_setaffinity
 849         .long sys_sched_getaffinity
 850         .long sys_ni_syscall    /* sys_set_thread_area */
 851         .long sys_ni_syscall    /* sys_get_thread_area */
 852         .long sys_io_setup      /* 245 */
 853         .long sys_io_destroy
 854         .long sys_io_getevents
 855         .long sys_io_submit
 856         .long sys_io_cancel
 857         .long sys_fadvise64     /* 250 */
 858         .long sys_ni_syscall
 859         .long sys_exit_group
 860         .long sys_lookup_dcookie
 861         .long sys_epoll_create
 862         .long sys_epoll_ctl     /* 255 */
 863         .long sys_epoll_wait
 864         .long sys_remap_file_pages
 865         .long sys_set_tid_address
 866         .long sys_timer_create
 867         .long sys_timer_settime         /* 260 */
 868         .long sys_timer_gettime
 869         .long sys_timer_getoverrun
 870         .long sys_timer_delete
 871         .long sys_clock_settime
 872         .long sys_clock_gettime         /* 265 */
 873         .long sys_clock_getres
 874         .long sys_clock_nanosleep
 875         .long sys_statfs64
 876         .long sys_fstatfs64
 877         .long sys_tgkill                /* 270 */
 878         .long sys_utimes
 879         .long sys_fadvise64_64
 880         .long sys_ni_syscall    /* sys_vserver */
 881         .long sys_ni_syscall    /* sys_mbind */
 882         .long sys_ni_syscall    /* 275 sys_get_mempolicy */
 883         .long sys_ni_syscall    /* sys_set_mempolicy */
 884         .long sys_mq_open
 885         .long sys_mq_unlink
 886         .long sys_mq_timedsend
 887         .long sys_mq_timedreceive       /* 280 */
 888         .long sys_mq_notify
 889         .long sys_mq_getsetattr
 890         .long sys_ni_syscall
 891         .long sys_waitid
 892         .long sys_ni_syscall            /* 285 */ /* available */
 893         .long sys_add_key
 894         .long sys_request_key
 895         .long sys_keyctl
 896         .long sys_ioprio_set
 897         .long sys_ioprio_get            /* 290 */
 898         .long sys_inotify_init
 899         .long sys_inotify_add_watch
 900         .long sys_inotify_rm_watch
 901         .long sys_migrate_pages
 902         .long sys_openat                /* 295 */
 903         .long sys_mkdirat
 904         .long sys_mknodat
 905         .long sys_fchownat
 906         .long sys_futimesat
 907         .long sys_fstatat64             /* 300 */
 908         .long sys_unlinkat
 909         .long sys_renameat
 910         .long sys_linkat
 911         .long sys_symlinkat
 912         .long sys_readlinkat            /* 305 */
 913         .long sys_fchmodat
 914         .long sys_faccessat
 915         .long sys_pselect6
 916         .long sys_ppoll
 917         .long sys_unshare               /* 310 */
 918         .long sys_set_robust_list
 919         .long sys_get_robust_list
 920         .long sys_splice
 921         .long sys_sync_file_range
 922         .long sys_tee                   /* 315 */
 923         .long sys_vmsplice
 924         .long sys_move_pages
 925         .long sys_getcpu
 926         .long sys_epoll_pwait
 927         .long sys_utimensat             /* 320 */
 928         .long sys_signalfd
 929         .long sys_timerfd_create
 930         .long sys_eventfd
 931         .long sys_fallocate
 932         .long sys_timerfd_settime       /* 325 */
 933         .long sys_timerfd_gettime
 934         .long sys_signalfd4
 935         .long sys_eventfd2
 936         .long sys_epoll_create1
 937         .long sys_dup3                  /* 330 */
 938         .long sys_pipe2
 939         .long sys_inotify_init1
 940         .long sys_preadv
 941         .long sys_pwritev
 942         .long sys_setns                 /* 335 */
 943         .long sys_name_to_handle_at
 944         .long sys_open_by_handle_at
 945         .long sys_rt_tgsigqueueinfo
 946         .long sys_perf_event_open
 947         .long sys_recvmmsg              /* 340 */
 948         .long sys_accept4
 949         .long sys_fanotify_init
 950         .long sys_fanotify_mark
 951         .long sys_prlimit64
 952         .long sys_clock_adjtime         /* 345 */
 953         .long sys_syncfs
 954         .long sys_sendmmsg
 955         .long sys_process_vm_readv
 956         .long sys_process_vm_writev
 957         .long sys_kcmp                  /* 350 */
 958         .long sys_finit_module
 959         .long sys_sched_setattr
 960         .long sys_sched_getattr
 961         .long sys_renameat2
 962         .long sys_seccomp               /* 355 */
 963         .long sys_getrandom
 964         .long sys_memfd_create
 965         .long sys_bpf
 966         .long sys_execveat
 967
 968         /*
 969          * NOTE!! This doesn't have to be exact - we just have
 970          * to make sure we have _enough_ of the "sys_ni_syscall"
 971          * entries. Don't panic if you notice that this hasn't
 972          * been shrunk every time we add a new system call.
 973          */
 974
 975         .rept NR_syscalls-(.-sys_call_table)/4
 976                 .long sys_ni_syscall
 977         .endr
 978