256 lines
6.1 KiB
C
256 lines
6.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* This file contains the routines setting up the linux page tables.
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* -- paulus
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*
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* Derived from arch/ppc/mm/init.c:
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* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
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*
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* Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
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* and Cort Dougan (PReP) (cort@cs.nmt.edu)
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* Copyright (C) 1996 Paul Mackerras
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*
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* Derived from "arch/i386/mm/init.c"
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* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/mm.h>
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#include <linux/vmalloc.h>
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#include <linux/init.h>
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#include <linux/highmem.h>
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#include <linux/memblock.h>
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#include <linux/slab.h>
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#include <asm/pgtable.h>
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#include <asm/pgalloc.h>
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#include <asm/fixmap.h>
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#include <asm/setup.h>
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#include <asm/sections.h>
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#include <mm/mmu_decl.h>
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extern char etext[], _stext[], _sinittext[], _einittext[];
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static void __init *early_alloc_pgtable(unsigned long size)
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{
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void *ptr = memblock_alloc(size, size);
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if (!ptr)
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panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
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__func__, size, size);
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return ptr;
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}
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static pte_t __init *early_pte_alloc_kernel(pmd_t *pmdp, unsigned long va)
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{
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if (pmd_none(*pmdp)) {
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pte_t *ptep = early_alloc_pgtable(PTE_FRAG_SIZE);
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pmd_populate_kernel(&init_mm, pmdp, ptep);
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}
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return pte_offset_kernel(pmdp, va);
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}
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int __ref map_kernel_page(unsigned long va, phys_addr_t pa, pgprot_t prot)
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{
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pmd_t *pd;
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pte_t *pg;
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int err = -ENOMEM;
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/* Use upper 10 bits of VA to index the first level map */
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pd = pmd_offset(pud_offset(pgd_offset_k(va), va), va);
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/* Use middle 10 bits of VA to index the second-level map */
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if (likely(slab_is_available()))
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pg = pte_alloc_kernel(pd, va);
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else
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pg = early_pte_alloc_kernel(pd, va);
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if (pg != 0) {
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err = 0;
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/* The PTE should never be already set nor present in the
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* hash table
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*/
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BUG_ON((pte_present(*pg) | pte_hashpte(*pg)) && pgprot_val(prot));
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set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, prot));
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}
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smp_wmb();
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return err;
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}
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/*
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* Map in a chunk of physical memory starting at start.
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*/
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static void __init __mapin_ram_chunk(unsigned long offset, unsigned long top)
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{
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unsigned long v, s;
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phys_addr_t p;
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int ktext;
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s = offset;
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v = PAGE_OFFSET + s;
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p = memstart_addr + s;
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for (; s < top; s += PAGE_SIZE) {
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ktext = ((char *)v >= _stext && (char *)v < etext) ||
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((char *)v >= _sinittext && (char *)v < _einittext);
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map_kernel_page(v, p, ktext ? PAGE_KERNEL_TEXT : PAGE_KERNEL);
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#ifdef CONFIG_PPC_BOOK3S_32
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if (ktext)
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hash_preload(&init_mm, v);
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#endif
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v += PAGE_SIZE;
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p += PAGE_SIZE;
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}
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}
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void __init mapin_ram(void)
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{
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struct memblock_region *reg;
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for_each_memblock(memory, reg) {
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phys_addr_t base = reg->base;
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phys_addr_t top = min(base + reg->size, total_lowmem);
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if (base >= top)
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continue;
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base = mmu_mapin_ram(base, top);
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if (IS_ENABLED(CONFIG_BDI_SWITCH))
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__mapin_ram_chunk(reg->base, top);
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else
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__mapin_ram_chunk(base, top);
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}
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}
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/* Scan the real Linux page tables and return a PTE pointer for
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* a virtual address in a context.
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* Returns true (1) if PTE was found, zero otherwise. The pointer to
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* the PTE pointer is unmodified if PTE is not found.
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*/
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static int
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get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp)
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{
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pgd_t *pgd;
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pud_t *pud;
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pmd_t *pmd;
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pte_t *pte;
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int retval = 0;
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pgd = pgd_offset(mm, addr & PAGE_MASK);
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if (pgd) {
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pud = pud_offset(pgd, addr & PAGE_MASK);
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if (pud && pud_present(*pud)) {
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pmd = pmd_offset(pud, addr & PAGE_MASK);
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if (pmd_present(*pmd)) {
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pte = pte_offset_map(pmd, addr & PAGE_MASK);
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if (pte) {
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retval = 1;
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*ptep = pte;
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if (pmdp)
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*pmdp = pmd;
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/* XXX caller needs to do pte_unmap, yuck */
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}
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}
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}
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}
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return(retval);
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}
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static int __change_page_attr_noflush(struct page *page, pgprot_t prot)
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{
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pte_t *kpte;
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pmd_t *kpmd;
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unsigned long address;
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BUG_ON(PageHighMem(page));
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address = (unsigned long)page_address(page);
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if (v_block_mapped(address))
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return 0;
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if (!get_pteptr(&init_mm, address, &kpte, &kpmd))
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return -EINVAL;
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__set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0);
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pte_unmap(kpte);
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return 0;
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}
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/*
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* Change the page attributes of an page in the linear mapping.
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*
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* THIS DOES NOTHING WITH BAT MAPPINGS, DEBUG USE ONLY
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*/
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static int change_page_attr(struct page *page, int numpages, pgprot_t prot)
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{
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int i, err = 0;
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unsigned long flags;
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struct page *start = page;
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local_irq_save(flags);
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for (i = 0; i < numpages; i++, page++) {
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err = __change_page_attr_noflush(page, prot);
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if (err)
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break;
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}
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wmb();
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local_irq_restore(flags);
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flush_tlb_kernel_range((unsigned long)page_address(start),
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(unsigned long)page_address(page));
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return err;
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}
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void mark_initmem_nx(void)
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{
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struct page *page = virt_to_page(_sinittext);
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unsigned long numpages = PFN_UP((unsigned long)_einittext) -
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PFN_DOWN((unsigned long)_sinittext);
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if (v_block_mapped((unsigned long)_stext + 1))
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mmu_mark_initmem_nx();
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else
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change_page_attr(page, numpages, PAGE_KERNEL);
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}
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#ifdef CONFIG_STRICT_KERNEL_RWX
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void mark_rodata_ro(void)
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{
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struct page *page;
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unsigned long numpages;
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if (v_block_mapped((unsigned long)_sinittext)) {
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mmu_mark_rodata_ro();
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return;
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}
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page = virt_to_page(_stext);
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numpages = PFN_UP((unsigned long)_etext) -
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PFN_DOWN((unsigned long)_stext);
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change_page_attr(page, numpages, PAGE_KERNEL_ROX);
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/*
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* mark .rodata as read only. Use __init_begin rather than __end_rodata
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* to cover NOTES and EXCEPTION_TABLE.
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*/
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page = virt_to_page(__start_rodata);
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numpages = PFN_UP((unsigned long)__init_begin) -
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PFN_DOWN((unsigned long)__start_rodata);
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change_page_attr(page, numpages, PAGE_KERNEL_RO);
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// mark_initmem_nx() should have already run by now
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ptdump_check_wx();
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}
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#endif
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#ifdef CONFIG_DEBUG_PAGEALLOC
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void __kernel_map_pages(struct page *page, int numpages, int enable)
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{
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if (PageHighMem(page))
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return;
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change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));
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}
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#endif /* CONFIG_DEBUG_PAGEALLOC */
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