arch/tile/kernel/entry.S

   1 /*
   2  * Copyright 2010 Tilera Corporation. All Rights Reserved.
   3  *
   4  *   This program is free software; you can redistribute it and/or
   5  *   modify it under the terms of the GNU General Public License
   6  *   as published by the Free Software Foundation, version 2.
   7  *
   8  *   This program is distributed in the hope that it will be useful, but
   9  *   WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  11  *   NON INFRINGEMENT.  See the GNU General Public License for
  12  *   more details.
  13  */
  14
  15 #include <linux/linkage.h>
  16 #include <linux/unistd.h>
  17 #include <asm/irqflags.h>
  18 #include <asm/processor.h>
  19 #include <arch/abi.h>
  20 #include <arch/spr_def.h>
  21
  22 #ifdef __tilegx__
  23 #define bnzt bnezt
  24 #endif
  25
  26 STD_ENTRY(current_text_addr)
  27         { move r0, lr; jrp lr }
  28         STD_ENDPROC(current_text_addr)
  29
  30 STD_ENTRY(dump_stack)
  31         { move r2, lr; lnk r1 }
  32         { move r4, r52; addli r1, r1, dump_stack - . }
  33         { move r3, sp; j _dump_stack }
  34         jrp lr   /* keep backtracer happy */
  35         STD_ENDPROC(dump_stack)
  36
  37 STD_ENTRY(KBacktraceIterator_init_current)
  38         { move r2, lr; lnk r1 }
  39         { move r4, r52; addli r1, r1, KBacktraceIterator_init_current - . }
  40         { move r3, sp; j _KBacktraceIterator_init_current }
  41         jrp lr   /* keep backtracer happy */
  42         STD_ENDPROC(KBacktraceIterator_init_current)
  43
  44 /* Loop forever on a nap during SMP boot. */
  45 STD_ENTRY(smp_nap)
  46         nap
  47         nop       /* avoid provoking the icache prefetch with a jump */
  48         j smp_nap /* we are not architecturally guaranteed not to exit nap */
  49         jrp lr    /* clue in the backtracer */
  50         STD_ENDPROC(smp_nap)
  51
  52 /*
  53  * Enable interrupts racelessly and then nap until interrupted.
  54  * Architecturally, we are guaranteed that enabling interrupts via
  55  * mtspr to INTERRUPT_CRITICAL_SECTION only interrupts at the next PC.
  56  * This function's _cpu_idle_nap address is special; see intvec.S.
  57  * When interrupted at _cpu_idle_nap, we bump the PC forward 8, and
  58  * as a result return to the function that called _cpu_idle().
  59  */
  60 STD_ENTRY(_cpu_idle)
  61         movei r1, 1
  62         IRQ_ENABLE_LOAD(r2, r3)
  63         mtspr INTERRUPT_CRITICAL_SECTION, r1
  64         IRQ_ENABLE_APPLY(r2, r3)       /* unmask, but still with ICS set */
  65         mtspr INTERRUPT_CRITICAL_SECTION, zero
  66         .global _cpu_idle_nap
  67 _cpu_idle_nap:
  68         nap
  69         nop       /* avoid provoking the icache prefetch with a jump */
  70         jrp lr
  71         STD_ENDPROC(_cpu_idle)