arch/powerpc/kernel/epapr_paravirt.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * ePAPR para-virtualization support.
   4  *
   5  * Copyright (C) 2012 Freescale Semiconductor, Inc.
   6  */
   7
   8 #include <linux/of.h>
   9 #include <linux/of_fdt.h>
  10 #include <asm/epapr_hcalls.h>
  11 #include <asm/cacheflush.h>
  12 #include <asm/code-patching.h>
  13 #include <asm/machdep.h>
  14
  15 #if !defined(CONFIG_64BIT) || defined(CONFIG_PPC_BOOK3E_64)
  16 extern void epapr_ev_idle(void);
  17 extern u32 epapr_ev_idle_start[];
  18 #endif
  19
  20 bool epapr_paravirt_enabled;
  21 static bool __maybe_unused epapr_has_idle;
  22
  23 static int __init early_init_dt_scan_epapr(unsigned long node,
  24                                            const char *uname,
  25                                            int depth, void *data)
  26 {
  27         const u32 *insts;
  28         int len;
  29         int i;
  30
  31         insts = of_get_flat_dt_prop(node, "hcall-instructions", &len);
  32         if (!insts)
  33                 return 0;
  34
  35         if (len % 4 || len > (4 * 4))
  36                 return -1;
  37
  38         for (i = 0; i < (len / 4); i++) {
  39                 u32 inst = be32_to_cpu(insts[i]);
  40                 patch_instruction(epapr_hypercall_start + i, inst);
  41 #if !defined(CONFIG_64BIT) || defined(CONFIG_PPC_BOOK3E_64)
  42                 patch_instruction(epapr_ev_idle_start + i, inst);
  43 #endif
  44         }
  45
  46 #if !defined(CONFIG_64BIT) || defined(CONFIG_PPC_BOOK3E_64)
  47         if (of_get_flat_dt_prop(node, "has-idle", NULL))
  48                 epapr_has_idle = true;
  49 #endif
  50
  51         epapr_paravirt_enabled = true;
  52
  53         return 1;
  54 }
  55
  56 int __init epapr_paravirt_early_init(void)
  57 {
  58         of_scan_flat_dt(early_init_dt_scan_epapr, NULL);
  59
  60         return 0;
  61 }
  62
  63 static int __init epapr_idle_init(void)
  64 {
  65 #if !defined(CONFIG_64BIT) || defined(CONFIG_PPC_BOOK3E_64)
  66         if (epapr_has_idle)
  67                 ppc_md.power_save = epapr_ev_idle;
  68 #endif
  69
  70         return 0;
  71 }
  72
  73 postcore_initcall(epapr_idle_init);