// 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_ptr_k(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); __mapin_ram_chunk(base, top); } } static int __change_page_attr_noflush(struct page *page, pgprot_t prot) { pte_t *kpte; unsigned long address; BUG_ON(PageHighMem(page)); address = (unsigned long)page_address(page); if (v_block_mapped(address)) return 0; kpte = virt_to_kpte(address); if (!kpte) return -EINVAL; __set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0); 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(); ptdump_check_wx(); 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 */