LXR linux/arch/powerpc/kernel/idle

   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#include <asm/epapr_hcalls.h>
  20
  21/* 64-bit version only for now */
  22#ifdef CONFIG_PPC64
  23
  24.macro BOOK3E_IDLE name loop
  25_GLOBAL(\name)
  26        /* Save LR for later */
  27        mflr    r0
  28        std     r0,16(r1)
  29
  30        /* Hard disable interrupts */
  31        wrteei  0
  32
  33        /* Now check if an interrupt came in while we were soft disabled
  34         * since we may otherwise lose it (doorbells etc...).
  35         */
  36        lbz     r3,PACAIRQHAPPENED(r13)
  37        cmpwi   cr0,r3,0
  38        bnelr
  39
  40        /* Now we are going to mark ourselves as soft and hard enabled in
  41         * order to be able to take interrupts while asleep. We inform lockdep
  42         * of that. We don't actually turn interrupts on just yet tho.
  43         */
  44#ifdef CONFIG_TRACE_IRQFLAGS
  45        stdu    r1,-128(r1)
  46        bl      trace_hardirqs_on
  47        addi    r1,r1,128
  48#endif
  49        li      r0,1
  50        stb     r0,PACASOFTIRQEN(r13)
  51        
  52        /* Interrupts will make use return to LR, so get something we want
  53         * in there
  54         */
  55        bl      1f
  56
  57        /* And return (interrupts are on) */
  58        ld      r0,16(r1)
  59        mtlr    r0
  60        blr
  61
  621:      /* Let's set the _TLF_NAPPING flag so interrupts make us return
  63         * to the right spot
  64        */
  65        CURRENT_THREAD_INFO(r11, r1)
  66        ld      r10,TI_LOCAL_FLAGS(r11)
  67        ori     r10,r10,_TLF_NAPPING
  68        std     r10,TI_LOCAL_FLAGS(r11)
  69
  70        /* We can now re-enable hard interrupts and go to sleep */
  71        wrteei  1
  72        \loop
  73
  74.endm
  75
  76.macro BOOK3E_IDLE_LOOP
  771:
  78        PPC_WAIT(0)
  79        b       1b
  80.endm
  81
  82/* epapr_ev_idle_start below is patched with the proper hcall
  83   opcodes during kernel initialization */
  84.macro EPAPR_EV_IDLE_LOOP
  85idle_loop:
  86        LOAD_REG_IMMEDIATE(r11, EV_HCALL_TOKEN(EV_IDLE))
  87
  88.global epapr_ev_idle_start
  89epapr_ev_idle_start:
  90        li      r3, -1
  91        nop
  92        nop
  93        nop
  94        b       idle_loop
  95.endm
  96
  97BOOK3E_IDLE epapr_ev_idle EPAPR_EV_IDLE_LOOP
  98
  99BOOK3E_IDLE book3e_idle BOOK3E_IDLE_LOOP
 100
 101#endif /* CONFIG_PPC64 */
 102