arch/openrisc/mm/ioremap.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * OpenRISC ioremap.c
   4  *
   5  * Linux architectural port borrowing liberally from similar works of
   6  * others.  All original copyrights apply as per the original source
   7  * declaration.
   8  *
   9  * Modifications for the OpenRISC architecture:
  10  * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
  11  * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
  12  */
  13
  14 #include <linux/vmalloc.h>
  15 #include <linux/io.h>
  16 #include <linux/pgtable.h>
  17 #include <asm/pgalloc.h>
  18 #include <asm/fixmap.h>
  19 #include <asm/bug.h>
  20 #include <linux/sched.h>
  21 #include <asm/tlbflush.h>
  22
  23 extern int mem_init_done;
  24
  25 /*
  26  * OK, this one's a bit tricky... ioremap can get called before memory is
  27  * initialized (early serial console does this) and will want to alloc a page
  28  * for its mapping.  No userspace pages will ever get allocated before memory
  29  * is initialized so this applies only to kernel pages.  In the event that
  30  * this is called before memory is initialized we allocate the page using
  31  * the memblock infrastructure.
  32  */
  33
  34 pte_t __ref *pte_alloc_one_kernel(struct mm_struct *mm)
  35 {
  36         pte_t *pte;
  37
  38         if (likely(mem_init_done)) {
  39                 pte = (pte_t *)get_zeroed_page(GFP_KERNEL);
  40         } else {
  41                 pte = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
  42                 if (!pte)
  43                         panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
  44                               __func__, PAGE_SIZE, PAGE_SIZE);
  45         }
  46
  47         return pte;
  48 }