LXR linux/arch/powerpc/mm/nohash/book3e

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Copyright 2005, Paul Mackerras, IBM Corporation.
   4 * Copyright 2009, Benjamin Herrenschmidt, IBM Corporation.
   5 * Copyright 2015-2016, Aneesh Kumar K.V, IBM Corporation.
   6 */
   7
   8#include <linux/sched.h>
   9#include <linux/memblock.h>
  10#include <asm/pgalloc.h>
  11#include <asm/tlb.h>
  12#include <asm/dma.h>
  13
  14#include <mm/mmu_decl.h>
  15
  16#ifdef CONFIG_SPARSEMEM_VMEMMAP
  17/*
  18 * On Book3E CPUs, the vmemmap is currently mapped in the top half of
  19 * the vmalloc space using normal page tables, though the size of
  20 * pages encoded in the PTEs can be different
  21 */
  22int __meminit vmemmap_create_mapping(unsigned long start,
  23                                     unsigned long page_size,
  24                                     unsigned long phys)
  25{
  26        /* Create a PTE encoding without page size */
  27        unsigned long i, flags = _PAGE_PRESENT | _PAGE_ACCESSED |
  28                _PAGE_KERNEL_RW;
  29
  30        /* PTEs only contain page size encodings up to 32M */
  31        BUG_ON(mmu_psize_defs[mmu_vmemmap_psize].enc > 0xf);
  32
  33        /* Encode the size in the PTE */
  34        flags |= mmu_psize_defs[mmu_vmemmap_psize].enc << 8;
  35
  36        /* For each PTE for that area, map things. Note that we don't
  37         * increment phys because all PTEs are of the large size and
  38         * thus must have the low bits clear
  39         */
  40        for (i = 0; i < page_size; i += PAGE_SIZE)
  41                BUG_ON(map_kernel_page(start + i, phys, __pgprot(flags)));
  42
  43        return 0;
  44}
  45
  46#ifdef CONFIG_MEMORY_HOTPLUG
  47void vmemmap_remove_mapping(unsigned long start,
  48                            unsigned long page_size)
  49{
  50}
  51#endif
  52#endif /* CONFIG_SPARSEMEM_VMEMMAP */
  53
  54static void __init *early_alloc_pgtable(unsigned long size)
  55{
  56        void *ptr;
  57
  58        ptr = memblock_alloc_try_nid(size, size, MEMBLOCK_LOW_LIMIT,
  59                                     __pa(MAX_DMA_ADDRESS), NUMA_NO_NODE);
  60
  61        if (!ptr)
  62                panic("%s: Failed to allocate %lu bytes align=0x%lx max_addr=%lx\n",
  63                      __func__, size, size, __pa(MAX_DMA_ADDRESS));
  64
  65        return ptr;
  66}
  67
  68/*
  69 * map_kernel_page currently only called by __ioremap
  70 * map_kernel_page adds an entry to the ioremap page table
  71 * and adds an entry to the HPT, possibly bolting it
  72 */
  73int __ref map_kernel_page(unsigned long ea, unsigned long pa, pgprot_t prot)
  74{
  75        pgd_t *pgdp;
  76        p4d_t *p4dp;
  77        pud_t *pudp;
  78        pmd_t *pmdp;
  79        pte_t *ptep;
  80
  81        BUILD_BUG_ON(TASK_SIZE_USER64 > PGTABLE_RANGE);
  82        if (slab_is_available()) {
  83                pgdp = pgd_offset_k(ea);
  84                p4dp = p4d_offset(pgdp, ea);
  85                pudp = pud_alloc(&init_mm, p4dp, ea);
  86                if (!pudp)
  87                        return -ENOMEM;
  88                pmdp = pmd_alloc(&init_mm, pudp, ea);
  89                if (!pmdp)
  90                        return -ENOMEM;
  91                ptep = pte_alloc_kernel(pmdp, ea);
  92                if (!ptep)
  93                        return -ENOMEM;
  94        } else {
  95                pgdp = pgd_offset_k(ea);
  96                p4dp = p4d_offset(pgdp, ea);
  97                if (p4d_none(*p4dp)) {
  98                        pmdp = early_alloc_pgtable(PMD_TABLE_SIZE);
  99                        p4d_populate(&init_mm, p4dp, pmdp);
 100                }
 101                pudp = pud_offset(p4dp, ea);
 102                if (pud_none(*pudp)) {
 103                        pmdp = early_alloc_pgtable(PMD_TABLE_SIZE);
 104                        pud_populate(&init_mm, pudp, pmdp);
 105                }
 106                pmdp = pmd_offset(pudp, ea);
 107                if (!pmd_present(*pmdp)) {
 108                        ptep = early_alloc_pgtable(PAGE_SIZE);
 109                        pmd_populate_kernel(&init_mm, pmdp, ptep);
 110                }
 111                ptep = pte_offset_kernel(pmdp, ea);
 112        }
 113        set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT, prot));
 114
 115        smp_wmb();
 116        return 0;
 117}
 118