arch/powerpc/kernel/epapr_paravirt.c

   1 /*
   2  * ePAPR para-virtualization support.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License, version 2, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program; if not, write to the Free Software
  15  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  16  *
  17  * Copyright (C) 2012 Freescale Semiconductor, Inc.
  18  */
  19
  20 #include <linux/of.h>
  21 #include <linux/of_fdt.h>
  22 #include <asm/epapr_hcalls.h>
  23 #include <asm/cacheflush.h>
  24 #include <asm/code-patching.h>
  25 #include <asm/machdep.h>
  26
  27 #if !defined(CONFIG_64BIT) || defined(CONFIG_PPC_BOOK3E_64)
  28 extern void epapr_ev_idle(void);
  29 extern u32 epapr_ev_idle_start[];
  30 #endif
  31
  32 bool epapr_paravirt_enabled;
  33 static bool __maybe_unused epapr_has_idle;
  34
  35 static int __init early_init_dt_scan_epapr(unsigned long node,
  36                                            const char *uname,
  37                                            int depth, void *data)
  38 {
  39         const u32 *insts;
  40         int len;
  41         int i;
  42
  43         insts = of_get_flat_dt_prop(node, "hcall-instructions", &len);
  44         if (!insts)
  45                 return 0;
  46
  47         if (len % 4 || len > (4 * 4))
  48                 return -1;
  49
  50         for (i = 0; i < (len / 4); i++) {
  51                 u32 inst = be32_to_cpu(insts[i]);
  52                 patch_instruction(epapr_hypercall_start + i, inst);
  53 #if !defined(CONFIG_64BIT) || defined(CONFIG_PPC_BOOK3E_64)
  54                 patch_instruction(epapr_ev_idle_start + i, inst);
  55 #endif
  56         }
  57
  58 #if !defined(CONFIG_64BIT) || defined(CONFIG_PPC_BOOK3E_64)
  59         if (of_get_flat_dt_prop(node, "has-idle", NULL))
  60                 epapr_has_idle = true;
  61 #endif
  62
  63         epapr_paravirt_enabled = true;
  64
  65         return 1;
  66 }
  67
  68 int __init epapr_paravirt_early_init(void)
  69 {
  70         of_scan_flat_dt(early_init_dt_scan_epapr, NULL);
  71
  72         return 0;
  73 }
  74
  75 static int __init epapr_idle_init(void)
  76 {
  77 #if !defined(CONFIG_64BIT) || defined(CONFIG_PPC_BOOK3E_64)
  78         if (epapr_has_idle)
  79                 ppc_md.power_save = epapr_ev_idle;
  80 #endif
  81
  82         return 0;
  83 }
  84
  85 postcore_initcall(epapr_idle_init);