LXR linux/arch/powerpc/kernel/idle

   1/* SPDX-License-Identifier: GPL-2.0-or-later */
   2/*
   3 * Copyright 2010 IBM Corp, Benjamin Herrenschmidt <benh@kernel.crashing.org>
   4 *
   5 * Generic idle routine for Book3E processors
   6 */
   7
   8#include <linux/threads.h>
   9#include <asm/reg.h>
  10#include <asm/ppc_asm.h>
  11#include <asm/asm-offsets.h>
  12#include <asm/ppc-opcode.h>
  13#include <asm/processor.h>
  14#include <asm/thread_info.h>
  15#include <asm/epapr_hcalls.h>
  16#include <asm/hw_irq.h>
  17
  18/* 64-bit version only for now */
  19#ifdef CONFIG_PPC64
  20
  21.macro BOOK3E_IDLE name loop
  22_GLOBAL(\name)
  23        /* Save LR for later */
  24        mflr    r0
  25        std     r0,16(r1)
  26
  27        /* Hard disable interrupts */
  28        wrteei  0
  29
  30        /* Now check if an interrupt came in while we were soft disabled
  31         * since we may otherwise lose it (doorbells etc...).
  32         */
  33        lbz     r3,PACAIRQHAPPENED(r13)
  34        cmpwi   cr0,r3,0
  35        bne     2f
  36
  37        /* Now we are going to mark ourselves as soft and hard enabled in
  38         * order to be able to take interrupts while asleep. We inform lockdep
  39         * of that. We don't actually turn interrupts on just yet tho.
  40         */
  41#ifdef CONFIG_TRACE_IRQFLAGS
  42        stdu    r1,-128(r1)
  43        bl      trace_hardirqs_on
  44        addi    r1,r1,128
  45#endif
  46        li      r0,IRQS_ENABLED
  47        stb     r0,PACAIRQSOFTMASK(r13)
  48        
  49        /* Interrupts will make use return to LR, so get something we want
  50         * in there
  51         */
  52        bl      1f
  53
  54        /* And return (interrupts are on) */
  55        ld      r0,16(r1)
  56        mtlr    r0
  57        blr
  58
  591:      /* Let's set the _TLF_NAPPING flag so interrupts make us return
  60         * to the right spot
  61        */
  62        ld      r11, PACACURRENT(r13)
  63        ld      r10,TI_LOCAL_FLAGS(r11)
  64        ori     r10,r10,_TLF_NAPPING
  65        std     r10,TI_LOCAL_FLAGS(r11)
  66
  67        /* We can now re-enable hard interrupts and go to sleep */
  68        wrteei  1
  69        \loop
  70
  712:
  72        lbz     r10,PACAIRQHAPPENED(r13)
  73        ori     r10,r10,PACA_IRQ_HARD_DIS
  74        stb     r10,PACAIRQHAPPENED(r13)
  75        blr
  76.endm
  77
  78.macro BOOK3E_IDLE_LOOP
  791:
  80        PPC_WAIT(0)
  81        b       1b
  82.endm
  83
  84/* epapr_ev_idle_start below is patched with the proper hcall
  85   opcodes during kernel initialization */
  86.macro EPAPR_EV_IDLE_LOOP
  87idle_loop:
  88        LOAD_REG_IMMEDIATE(r11, EV_HCALL_TOKEN(EV_IDLE))
  89
  90.global epapr_ev_idle_start
  91epapr_ev_idle_start:
  92        li      r3, -1
  93        nop
  94        nop
  95        nop
  96        b       idle_loop
  97.endm
  98
  99BOOK3E_IDLE epapr_ev_idle EPAPR_EV_IDLE_LOOP
 100
 101BOOK3E_IDLE book3e_idle BOOK3E_IDLE_LOOP
 102
 103#endif /* CONFIG_PPC64 */
 104