arch/powerpc/mm/pgtable_32.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * This file contains the routines setting up the linux page tables.
   4  *  -- paulus
   5  *
   6  *  Derived from arch/ppc/mm/init.c:
   7  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
   8  *
   9  *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
  10  *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
  11  *    Copyright (C) 1996 Paul Mackerras
  12  *
  13  *  Derived from "arch/i386/mm/init.c"
  14  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  15  */
  16
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19 #include <linux/types.h>
  20 #include <linux/mm.h>
  21 #include <linux/vmalloc.h>
  22 #include <linux/init.h>
  23 #include <linux/highmem.h>
  24 #include <linux/memblock.h>
  25 #include <linux/slab.h>
  26 #include <linux/set_memory.h>
  27
  28 #include <asm/pgalloc.h>
  29 #include <asm/fixmap.h>
  30 #include <asm/setup.h>
  31 #include <asm/sections.h>
  32 #include <asm/early_ioremap.h>
  33
  34 #include <mm/mmu_decl.h>
  35
  36 static u8 early_fixmap_pagetable[FIXMAP_PTE_SIZE] __page_aligned_data;
  37
  38 notrace void __init early_ioremap_init(void)
  39 {
  40         unsigned long addr = ALIGN_DOWN(FIXADDR_START, PGDIR_SIZE);
  41         pte_t *ptep = (pte_t *)early_fixmap_pagetable;
  42         pmd_t *pmdp = pmd_off_k(addr);
  43
  44         for (; (s32)(FIXADDR_TOP - addr) > 0;
  45              addr += PGDIR_SIZE, ptep += PTRS_PER_PTE, pmdp++)
  46                 pmd_populate_kernel(&init_mm, pmdp, ptep);
  47
  48         early_ioremap_setup();
  49 }
  50
  51 void __init *early_alloc_pgtable(unsigned long size)
  52 {
  53         void *ptr = memblock_alloc(size, size);
  54
  55         if (!ptr)
  56                 panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
  57                       __func__, size, size);
  58
  59         return ptr;
  60 }
  61
  62 pte_t __init *early_pte_alloc_kernel(pmd_t *pmdp, unsigned long va)
  63 {
  64         if (pmd_none(*pmdp)) {
  65                 pte_t *ptep = early_alloc_pgtable(PTE_FRAG_SIZE);
  66
  67                 pmd_populate_kernel(&init_mm, pmdp, ptep);
  68         }
  69         return pte_offset_kernel(pmdp, va);
  70 }
  71
  72
  73 int __ref map_kernel_page(unsigned long va, phys_addr_t pa, pgprot_t prot)
  74 {
  75         pmd_t *pd;
  76         pte_t *pg;
  77         int err = -ENOMEM;
  78
  79         /* Use upper 10 bits of VA to index the first level map */
  80         pd = pmd_off_k(va);
  81         /* Use middle 10 bits of VA to index the second-level map */
  82         if (likely(slab_is_available()))
  83                 pg = pte_alloc_kernel(pd, va);
  84         else
  85                 pg = early_pte_alloc_kernel(pd, va);
  86         if (pg) {
  87                 err = 0;
  88                 /* The PTE should never be already set nor present in the
  89                  * hash table
  90                  */
  91                 BUG_ON((pte_present(*pg) | pte_hashpte(*pg)) && pgprot_val(prot));
  92                 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, prot));
  93         }
  94         smp_wmb();
  95         return err;
  96 }
  97
  98 /*
  99  * Map in a chunk of physical memory starting at start.
 100  */
 101 static void __init __mapin_ram_chunk(unsigned long offset, unsigned long top)
 102 {
 103         unsigned long v, s;
 104         phys_addr_t p;
 105         bool ktext;
 106
 107         s = offset;
 108         v = PAGE_OFFSET + s;
 109         p = memstart_addr + s;
 110         for (; s < top; s += PAGE_SIZE) {
 111                 ktext = core_kernel_text(v);
 112                 map_kernel_page(v, p, ktext ? PAGE_KERNEL_TEXT : PAGE_KERNEL);
 113                 v += PAGE_SIZE;
 114                 p += PAGE_SIZE;
 115         }
 116 }
 117
 118 void __init mapin_ram(void)
 119 {
 120         phys_addr_t base, end;
 121         u64 i;
 122
 123         for_each_mem_range(i, &base, &end) {
 124                 phys_addr_t top = min(end, total_lowmem);
 125
 126                 if (base >= top)
 127                         continue;
 128                 base = mmu_mapin_ram(base, top);
 129                 __mapin_ram_chunk(base, top);
 130         }
 131 }
 132
 133 static int __mark_initmem_nx(void)
 134 {
 135         unsigned long numpages = PFN_UP((unsigned long)_einittext) -
 136                                  PFN_DOWN((unsigned long)_sinittext);
 137         int err;
 138
 139         err = mmu_mark_initmem_nx();
 140
 141         if (!v_block_mapped((unsigned long)_sinittext)) {
 142                 err = set_memory_nx((unsigned long)_sinittext, numpages);
 143                 if (err)
 144                         return err;
 145                 err = set_memory_rw((unsigned long)_sinittext, numpages);
 146         }
 147         return err;
 148 }
 149
 150 void mark_initmem_nx(void)
 151 {
 152         int err = __mark_initmem_nx();
 153
 154         if (err)
 155                 panic("%s() failed, err = %d\n", __func__, err);
 156 }
 157
 158 #ifdef CONFIG_STRICT_KERNEL_RWX
 159 static int __mark_rodata_ro(void)
 160 {
 161         unsigned long numpages;
 162
 163         if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX) && mmu_has_feature(MMU_FTR_HPTE_TABLE))
 164                 pr_warn("This platform has HASH MMU, STRICT_MODULE_RWX won't work\n");
 165
 166         if (v_block_mapped((unsigned long)_stext + 1))
 167                 return mmu_mark_rodata_ro();
 168
 169         /*
 170          * mark text and rodata as read only. __end_rodata is set by
 171          * powerpc's linker script and includes tables and data
 172          * requiring relocation which are not put in RO_DATA.
 173          */
 174         numpages = PFN_UP((unsigned long)__end_rodata) -
 175                    PFN_DOWN((unsigned long)_stext);
 176
 177         return set_memory_ro((unsigned long)_stext, numpages);
 178 }
 179
 180 void mark_rodata_ro(void)
 181 {
 182         int err = __mark_rodata_ro();
 183
 184         if (err)
 185                 panic("%s() failed, err = %d\n", __func__, err);
 186 }
 187 #endif