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#include <asm/code-patching.h>
  14
  15#include <mm/mmu_decl.h>
  16
  17#ifdef CONFIG_SPARSEMEM_VMEMMAP
  18/*
  19 * On Book3E CPUs, the vmemmap is currently mapped in the top half of
  20 * the vmalloc space using normal page tables, though the size of
  21 * pages encoded in the PTEs can be different
  22 */
  23int __meminit vmemmap_create_mapping(unsigned long start,
  24                                     unsigned long page_size,
  25                                     unsigned long phys)
  26{
  27        /* Create a PTE encoding without page size */
  28        unsigned long i, flags = _PAGE_PRESENT | _PAGE_ACCESSED |
  29                _PAGE_KERNEL_RW;
  30
  31        /* PTEs only contain page size encodings up to 32M */
  32        BUG_ON(mmu_psize_defs[mmu_vmemmap_psize].enc > 0xf);
  33
  34        /* Encode the size in the PTE */
  35        flags |= mmu_psize_defs[mmu_vmemmap_psize].enc << 8;
  36
  37        /* For each PTE for that area, map things. Note that we don't
  38         * increment phys because all PTEs are of the large size and
  39         * thus must have the low bits clear
  40         */
  41        for (i = 0; i < page_size; i += PAGE_SIZE)
  42                BUG_ON(map_kernel_page(start + i, phys, __pgprot(flags)));
  43
  44        return 0;
  45}
  46
  47#ifdef CONFIG_MEMORY_HOTPLUG
  48void vmemmap_remove_mapping(unsigned long start,
  49                            unsigned long page_size)
  50{
  51}
  52#endif
  53#endif /* CONFIG_SPARSEMEM_VMEMMAP */
  54
  55static void __init *early_alloc_pgtable(unsigned long size)
  56{
  57        void *ptr;
  58
  59        ptr = memblock_alloc_try_nid(size, size, MEMBLOCK_LOW_LIMIT,
  60                                     __pa(MAX_DMA_ADDRESS), NUMA_NO_NODE);
  61
  62        if (!ptr)
  63                panic("%s: Failed to allocate %lu bytes align=0x%lx max_addr=%lx\n",
  64                      __func__, size, size, __pa(MAX_DMA_ADDRESS));
  65
  66        return ptr;
  67}
  68
  69/*
  70 * map_kernel_page currently only called by __ioremap
  71 * map_kernel_page adds an entry to the ioremap page table
  72 * and adds an entry to the HPT, possibly bolting it
  73 */
  74int __ref map_kernel_page(unsigned long ea, unsigned long pa, pgprot_t prot)
  75{
  76        pgd_t *pgdp;
  77        p4d_t *p4dp;
  78        pud_t *pudp;
  79        pmd_t *pmdp;
  80        pte_t *ptep;
  81
  82        BUILD_BUG_ON(TASK_SIZE_USER64 > PGTABLE_RANGE);
  83        if (slab_is_available()) {
  84                pgdp = pgd_offset_k(ea);
  85                p4dp = p4d_offset(pgdp, ea);
  86                pudp = pud_alloc(&init_mm, p4dp, ea);
  87                if (!pudp)
  88                        return -ENOMEM;
  89                pmdp = pmd_alloc(&init_mm, pudp, ea);
  90                if (!pmdp)
  91                        return -ENOMEM;
  92                ptep = pte_alloc_kernel(pmdp, ea);
  93                if (!ptep)
  94                        return -ENOMEM;
  95        } else {
  96                pgdp = pgd_offset_k(ea);
  97                p4dp = p4d_offset(pgdp, ea);
  98                if (p4d_none(*p4dp)) {
  99                        pmdp = early_alloc_pgtable(PMD_TABLE_SIZE);
 100                        p4d_populate(&init_mm, p4dp, pmdp);
 101                }
 102                pudp = pud_offset(p4dp, ea);
 103                if (pud_none(*pudp)) {
 104                        pmdp = early_alloc_pgtable(PMD_TABLE_SIZE);
 105                        pud_populate(&init_mm, pudp, pmdp);
 106                }
 107                pmdp = pmd_offset(pudp, ea);
 108                if (!pmd_present(*pmdp)) {
 109                        ptep = early_alloc_pgtable(PAGE_SIZE);
 110                        pmd_populate_kernel(&init_mm, pmdp, ptep);
 111                }
 112                ptep = pte_offset_kernel(pmdp, ea);
 113        }
 114        set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT, prot));
 115
 116        smp_wmb();
 117        return 0;
 118}
 119
 120void __patch_exception(int exc, unsigned long addr)
 121{
 122        unsigned int *ibase = &interrupt_base_book3e;
 123
 124        /*
 125         * Our exceptions vectors start with a NOP and -then- a branch
 126         * to deal with single stepping from userspace which stops on
 127         * the second instruction. Thus we need to patch the second
 128         * instruction of the exception, not the first one.
 129         */
 130
 131        patch_branch(ibase + (exc / 4) + 1, addr, 0);
 132}
 133