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