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 <asm/epapr_hcalls.h>
  22 #include <asm/cacheflush.h>
  23 #include <asm/code-patching.h>
  24 #include <asm/machdep.h>
  25
  26 extern void epapr_ev_idle(void);
  27 extern u32 epapr_ev_idle_start[];
  28
  29 bool epapr_paravirt_enabled;
  30
  31 static int __init epapr_paravirt_init(void)
  32 {
  33         struct device_node *hyper_node;
  34         const u32 *insts;
  35         int len, i;
  36
  37         hyper_node = of_find_node_by_path("/hypervisor");
  38         if (!hyper_node)
  39                 return -ENODEV;
  40
  41         insts = of_get_property(hyper_node, "hcall-instructions", &len);
  42         if (!insts)
  43                 return -ENODEV;
  44
  45         if (len % 4 || len > (4 * 4))
  46                 return -ENODEV;
  47
  48         for (i = 0; i < (len / 4); i++) {
  49                 patch_instruction(epapr_hypercall_start + i, insts[i]);
  50                 patch_instruction(epapr_ev_idle_start + i, insts[i]);
  51         }
  52
  53         if (of_get_property(hyper_node, "has-idle", NULL))
  54                 ppc_md.power_save = epapr_ev_idle;
  55
  56         epapr_paravirt_enabled = true;
  57
  58         return 0;
  59 }
  60
  61 early_initcall(epapr_paravirt_init);