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 #include <asm/inst.h>
  15
  16 #if !defined(CONFIG_64BIT) || defined(CONFIG_PPC_BOOK3E_64)
  17 extern void epapr_ev_idle(void);
  18 extern u32 epapr_ev_idle_start[];
  19 #endif
  20
  21 bool epapr_paravirt_enabled;
  22 static bool __maybe_unused epapr_has_idle;
  23
  24 static int __init early_init_dt_scan_epapr(unsigned long node,
  25                                            const char *uname,
  26                                            int depth, void *data)
  27 {
  28         const u32 *insts;
  29         int len;
  30         int i;
  31
  32         insts = of_get_flat_dt_prop(node, "hcall-instructions", &len);
  33         if (!insts)
  34                 return 0;
  35
  36         if (len % 4 || len > (4 * 4))
  37                 return -1;
  38
  39         for (i = 0; i < (len / 4); i++) {
  40                 struct ppc_inst inst = ppc_inst(be32_to_cpu(insts[i]));
  41                 patch_instruction((struct ppc_inst *)(epapr_hypercall_start + i), inst);
  42 #if !defined(CONFIG_64BIT) || defined(CONFIG_PPC_BOOK3E_64)
  43                 patch_instruction((struct ppc_inst *)(epapr_ev_idle_start + i), inst);
  44 #endif
  45         }
  46
  47 #if !defined(CONFIG_64BIT) || defined(CONFIG_PPC_BOOK3E_64)
  48         if (of_get_flat_dt_prop(node, "has-idle", NULL))
  49                 epapr_has_idle = true;
  50 #endif
  51
  52         epapr_paravirt_enabled = true;
  53
  54         return 1;
  55 }
  56
  57 int __init epapr_paravirt_early_init(void)
  58 {
  59         of_scan_flat_dt(early_init_dt_scan_epapr, NULL);
  60
  61         return 0;
  62 }
  63
  64 static int __init epapr_idle_init(void)
  65 {
  66 #if !defined(CONFIG_64BIT) || defined(CONFIG_PPC_BOOK3E_64)
  67         if (epapr_has_idle)
  68                 ppc_md.power_save = epapr_ev_idle;
  69 #endif
  70
  71         return 0;
  72 }
  73
  74 postcore_initcall(epapr_idle_init);