arch/powerpc/mm/pgtable-hash64.c

   1 /*
   2  * Copyright 2005, Paul Mackerras, IBM Corporation.
   3  * Copyright 2009, Benjamin Herrenschmidt, IBM Corporation.
   4  * Copyright 2015-2016, Aneesh Kumar K.V, IBM Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/sched.h>
  13 #include <asm/pgalloc.h>
  14 #include <asm/tlb.h>
  15
  16 #include "mmu_decl.h"
  17
  18 #ifdef CONFIG_SPARSEMEM_VMEMMAP
  19 /*
  20  * On hash-based CPUs, the vmemmap is bolted in the hash table.
  21  *
  22  */
  23 int __meminit vmemmap_create_mapping(unsigned long start,
  24                                      unsigned long page_size,
  25                                      unsigned long phys)
  26 {
  27         int rc = htab_bolt_mapping(start, start + page_size, phys,
  28                                    pgprot_val(PAGE_KERNEL),
  29                                    mmu_vmemmap_psize, mmu_kernel_ssize);
  30         if (rc < 0) {
  31                 int rc2 = htab_remove_mapping(start, start + page_size,
  32                                               mmu_vmemmap_psize,
  33                                               mmu_kernel_ssize);
  34                 BUG_ON(rc2 && (rc2 != -ENOENT));
  35         }
  36         return rc;
  37 }
  38
  39 #ifdef CONFIG_MEMORY_HOTPLUG
  40 void vmemmap_remove_mapping(unsigned long start,
  41                             unsigned long page_size)
  42 {
  43         int rc = htab_remove_mapping(start, start + page_size,
  44                                      mmu_vmemmap_psize,
  45                                      mmu_kernel_ssize);
  46         BUG_ON((rc < 0) && (rc != -ENOENT));
  47         WARN_ON(rc == -ENOENT);
  48 }
  49 #endif
  50 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
  51
  52 /*
  53  * map_kernel_page currently only called by __ioremap
  54  * map_kernel_page adds an entry to the ioremap page table
  55  * and adds an entry to the HPT, possibly bolting it
  56  */
  57 int map_kernel_page(unsigned long ea, unsigned long pa, unsigned long flags)
  58 {
  59         pgd_t *pgdp;
  60         pud_t *pudp;
  61         pmd_t *pmdp;
  62         pte_t *ptep;
  63
  64         if (slab_is_available()) {
  65                 pgdp = pgd_offset_k(ea);
  66                 pudp = pud_alloc(&init_mm, pgdp, ea);
  67                 if (!pudp)
  68                         return -ENOMEM;
  69                 pmdp = pmd_alloc(&init_mm, pudp, ea);
  70                 if (!pmdp)
  71                         return -ENOMEM;
  72                 ptep = pte_alloc_kernel(pmdp, ea);
  73                 if (!ptep)
  74                         return -ENOMEM;
  75                 set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT,
  76                                                           __pgprot(flags)));
  77         } else {
  78                 /*
  79                  * If the mm subsystem is not fully up, we cannot create a
  80                  * linux page table entry for this mapping.  Simply bolt an
  81                  * entry in the hardware page table.
  82                  *
  83                  */
  84                 if (htab_bolt_mapping(ea, ea + PAGE_SIZE, pa, flags,
  85                                       mmu_io_psize, mmu_kernel_ssize)) {
  86                         printk(KERN_ERR "Failed to do bolted mapping IO "
  87                                "memory at %016lx !\n", pa);
  88                         return -ENOMEM;
  89                 }
  90         }
  91
  92         smp_wmb();
  93         return 0;
  94 }