root/arch/powerpc/kernel/epapr_hcalls.S

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * Copyright (C) 2012 Freescale Semiconductor, Inc.
   4  */
   5 
   6 #include <linux/threads.h>
   7 #include <asm/epapr_hcalls.h>
   8 #include <asm/reg.h>
   9 #include <asm/page.h>
  10 #include <asm/cputable.h>
  11 #include <asm/thread_info.h>
  12 #include <asm/ppc_asm.h>
  13 #include <asm/asm-compat.h>
  14 #include <asm/asm-offsets.h>
  15 #include <asm/export.h>
  16 
  17 #ifndef CONFIG_PPC64
  18 /* epapr_ev_idle() was derived from e500_idle() */
  19 _GLOBAL(epapr_ev_idle)
  20         PPC_LL  r4, TI_LOCAL_FLAGS(r2)  /* set napping bit */
  21         ori     r4, r4,_TLF_NAPPING     /* so when we take an exception */
  22         PPC_STL r4, TI_LOCAL_FLAGS(r2)  /* it will return to our caller */
  23 
  24         wrteei  1
  25 
  26 idle_loop:
  27         LOAD_REG_IMMEDIATE(r11, EV_HCALL_TOKEN(EV_IDLE))
  28 
  29 .global epapr_ev_idle_start
  30 epapr_ev_idle_start:
  31         li      r3, -1
  32         nop
  33         nop
  34         nop
  35 
  36         /*
  37          * Guard against spurious wakeups from a hypervisor --
  38          * only interrupt will cause us to return to LR due to
  39          * _TLF_NAPPING.
  40          */
  41         b       idle_loop
  42 #endif
  43 
  44 /* Hypercall entry point. Will be patched with device tree instructions. */
  45 .global epapr_hypercall_start
  46 epapr_hypercall_start:
  47         li      r3, -1
  48         nop
  49         nop
  50         nop
  51         blr
  52 EXPORT_SYMBOL(epapr_hypercall_start)