arch/powerpc/kernel/idle_book3e.S

   1 /*
   2  * Copyright 2010 IBM Corp, Benjamin Herrenschmidt <benh@kernel.crashing.org>
   3  *
   4  * Generic idle routine for Book3E processors
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/threads.h>
  13 #include <asm/reg.h>
  14 #include <asm/ppc_asm.h>
  15 #include <asm/asm-offsets.h>
  16 #include <asm/ppc-opcode.h>
  17 #include <asm/processor.h>
  18 #include <asm/thread_info.h>
  19
  20 /* 64-bit version only for now */
  21 #ifdef CONFIG_PPC64
  22
  23 _GLOBAL(book3e_idle)
  24         /* Save LR for later */
  25         mflr    r0
  26         std     r0,16(r1)
  27
  28         /* Hard disable interrupts */
  29         wrteei  0
  30
  31         /* Now check if an interrupt came in while we were soft disabled
  32          * since we may otherwise lose it (doorbells etc...). We know
  33          * that since PACAHARDIRQEN will have been cleared in that case.
  34          */
  35         lbz     r3,PACAHARDIRQEN(r13)
  36         cmpwi   cr0,r3,0
  37         beqlr
  38
  39         /* Now we are going to mark ourselves as soft and hard enables in
  40          * order to be able to take interrupts while asleep. We inform lockdep
  41          * of that. We don't actually turn interrupts on just yet tho.
  42          */
  43 #ifdef CONFIG_TRACE_IRQFLAGS
  44         stdu    r1,-128(r1)
  45         bl      .trace_hardirqs_on
  46 #endif
  47         li      r0,1
  48         stb     r0,PACASOFTIRQEN(r13)
  49         stb     r0,PACAHARDIRQEN(r13)
  50
  51         /* Interrupts will make use return to LR, so get something we want
  52          * in there
  53          */
  54         bl      1f
  55
  56         /* Hard disable interrupts again */
  57         wrteei  0
  58
  59         /* Mark them off again in the PACA as well */
  60         li      r0,0
  61         stb     r0,PACASOFTIRQEN(r13)
  62         stb     r0,PACAHARDIRQEN(r13)
  63
  64         /* Tell lockdep about it */
  65 #ifdef CONFIG_TRACE_IRQFLAGS
  66         bl      .trace_hardirqs_off
  67         addi    r1,r1,128
  68 #endif
  69         ld      r0,16(r1)
  70         mtlr    r0
  71         blr
  72
  73 1:      /* Let's set the _TLF_NAPPING flag so interrupts make us return
  74          * to the right spot
  75         */
  76         clrrdi  r11,r1,THREAD_SHIFT
  77         ld      r10,TI_LOCAL_FLAGS(r11)
  78         ori     r10,r10,_TLF_NAPPING
  79         std     r10,TI_LOCAL_FLAGS(r11)
  80
  81         /* We can now re-enable hard interrupts and go to sleep */
  82         wrteei  1
  83 1:      PPC_WAIT(0)
  84         b       1b
  85
  86 #endif /* CONFIG_PPC64 */