root/arch/powerpc/kernel/idle_book3e.S

   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 
  59 1:      /* 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 
  71 2:
  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
  79 1:
  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
  87 idle_loop:
  88         LOAD_REG_IMMEDIATE(r11, EV_HCALL_TOKEN(EV_IDLE))
  89 
  90 .global epapr_ev_idle_start
  91 epapr_ev_idle_start:
  92         li      r3, -1
  93         nop
  94         nop
  95         nop
  96         b       idle_loop
  97 .endm
  98 
  99 BOOK3E_IDLE epapr_ev_idle EPAPR_EV_IDLE_LOOP
 100 
 101 BOOK3E_IDLE book3e_idle BOOK3E_IDLE_LOOP
 102 
 103 #endif /* CONFIG_PPC64 */