2 * This file contains the routines setting up the linux page tables.
5 * Derived from arch/ppc/mm/init.c:
6 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
8 * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
9 * and Cort Dougan (PReP) (cort@cs.nmt.edu)
10 * Copyright (C) 1996 Paul Mackerras
12 * Derived from "arch/i386/mm/init.c"
13 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
15 * This program is free software; you can redistribute it and/or
16 * modify it under the terms of the GNU General Public License
17 * as published by the Free Software Foundation; either version
18 * 2 of the License, or (at your option) any later version.
22 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/types.h>
26 #include <linux/vmalloc.h>
27 #include <linux/init.h>
28 #include <linux/highmem.h>
29 #include <linux/memblock.h>
30 #include <linux/slab.h>
32 #include <asm/pgtable.h>
33 #include <asm/pgalloc.h>
34 #include <asm/fixmap.h>
36 #include <asm/setup.h>
37 #include <asm/sections.h>
39 #include <mm/mmu_decl.h>
41 unsigned long ioremap_bot;
42 EXPORT_SYMBOL(ioremap_bot); /* aka VMALLOC_END */
44 extern char etext[], _stext[], _sinittext[], _einittext[];
47 ioremap(phys_addr_t addr, unsigned long size)
49 pgprot_t prot = pgprot_noncached(PAGE_KERNEL);
51 return __ioremap_caller(addr, size, prot, __builtin_return_address(0));
53 EXPORT_SYMBOL(ioremap);
56 ioremap_wc(phys_addr_t addr, unsigned long size)
58 pgprot_t prot = pgprot_noncached_wc(PAGE_KERNEL);
60 return __ioremap_caller(addr, size, prot, __builtin_return_address(0));
62 EXPORT_SYMBOL(ioremap_wc);
65 ioremap_wt(phys_addr_t addr, unsigned long size)
67 pgprot_t prot = pgprot_cached_wthru(PAGE_KERNEL);
69 return __ioremap_caller(addr, size, prot, __builtin_return_address(0));
71 EXPORT_SYMBOL(ioremap_wt);
74 ioremap_coherent(phys_addr_t addr, unsigned long size)
76 pgprot_t prot = pgprot_cached(PAGE_KERNEL);
78 return __ioremap_caller(addr, size, prot, __builtin_return_address(0));
80 EXPORT_SYMBOL(ioremap_coherent);
83 ioremap_prot(phys_addr_t addr, unsigned long size, unsigned long flags)
85 pte_t pte = __pte(flags);
87 /* writeable implies dirty for kernel addresses */
89 pte = pte_mkdirty(pte);
91 /* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */
92 pte = pte_exprotect(pte);
93 pte = pte_mkprivileged(pte);
95 return __ioremap_caller(addr, size, pte_pgprot(pte), __builtin_return_address(0));
97 EXPORT_SYMBOL(ioremap_prot);
100 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
102 return __ioremap_caller(addr, size, __pgprot(flags), __builtin_return_address(0));
106 __ioremap_caller(phys_addr_t addr, unsigned long size, pgprot_t prot, void *caller)
113 * Choose an address to map it to.
114 * Once the vmalloc system is running, we use it.
115 * Before then, we use space going down from IOREMAP_TOP
116 * (ioremap_bot records where we're up to).
118 p = addr & PAGE_MASK;
119 size = PAGE_ALIGN(addr + size) - p;
122 * If the address lies within the first 16 MB, assume it's in ISA
125 if (p < 16*1024*1024)
128 #ifndef CONFIG_CRASH_DUMP
130 * Don't allow anybody to remap normal RAM that we're using.
131 * mem_init() sets high_memory so only do the check after that.
133 if (slab_is_available() && p <= virt_to_phys(high_memory - 1) &&
134 page_is_ram(__phys_to_pfn(p))) {
135 printk("__ioremap(): phys addr 0x%llx is RAM lr %ps\n",
136 (unsigned long long)p, __builtin_return_address(0));
145 * Is it already mapped? Perhaps overlapped by a previous
148 v = p_block_mapped(p);
152 if (slab_is_available()) {
153 struct vm_struct *area;
154 area = get_vm_area_caller(size, VM_IOREMAP, caller);
158 v = (unsigned long) area->addr;
160 v = (ioremap_bot -= size);
164 * Should check if it is a candidate for a BAT mapping
168 for (i = 0; i < size && err == 0; i += PAGE_SIZE)
169 err = map_kernel_page(v + i, p + i, prot);
171 if (slab_is_available())
177 return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
179 EXPORT_SYMBOL(__ioremap);
181 void iounmap(volatile void __iomem *addr)
184 * If mapped by BATs then there is nothing to do.
185 * Calling vfree() generates a benign warning.
187 if (v_block_mapped((unsigned long)addr))
190 if (addr > high_memory && (unsigned long) addr < ioremap_bot)
191 vunmap((void *) (PAGE_MASK & (unsigned long)addr));
193 EXPORT_SYMBOL(iounmap);
195 static void __init *early_alloc_pgtable(unsigned long size)
197 void *ptr = memblock_alloc(size, size);
200 panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
201 __func__, size, size);
206 static pte_t __init *early_pte_alloc_kernel(pmd_t *pmdp, unsigned long va)
208 if (pmd_none(*pmdp)) {
209 pte_t *ptep = early_alloc_pgtable(PTE_FRAG_SIZE);
211 pmd_populate_kernel(&init_mm, pmdp, ptep);
213 return pte_offset_kernel(pmdp, va);
217 int __ref map_kernel_page(unsigned long va, phys_addr_t pa, pgprot_t prot)
223 /* Use upper 10 bits of VA to index the first level map */
224 pd = pmd_offset(pud_offset(pgd_offset_k(va), va), va);
225 /* Use middle 10 bits of VA to index the second-level map */
226 if (likely(slab_is_available()))
227 pg = pte_alloc_kernel(pd, va);
229 pg = early_pte_alloc_kernel(pd, va);
232 /* The PTE should never be already set nor present in the
235 BUG_ON((pte_present(*pg) | pte_hashpte(*pg)) && pgprot_val(prot));
236 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, prot));
243 * Map in a chunk of physical memory starting at start.
245 static void __init __mapin_ram_chunk(unsigned long offset, unsigned long top)
253 p = memstart_addr + s;
254 for (; s < top; s += PAGE_SIZE) {
255 ktext = ((char *)v >= _stext && (char *)v < etext) ||
256 ((char *)v >= _sinittext && (char *)v < _einittext);
257 map_kernel_page(v, p, ktext ? PAGE_KERNEL_TEXT : PAGE_KERNEL);
258 #ifdef CONFIG_PPC_BOOK3S_32
260 hash_preload(&init_mm, v, false, 0x300);
267 void __init mapin_ram(void)
269 struct memblock_region *reg;
271 for_each_memblock(memory, reg) {
272 phys_addr_t base = reg->base;
273 phys_addr_t top = min(base + reg->size, total_lowmem);
277 base = mmu_mapin_ram(base, top);
278 if (IS_ENABLED(CONFIG_BDI_SWITCH))
279 __mapin_ram_chunk(reg->base, top);
281 __mapin_ram_chunk(base, top);
285 /* Scan the real Linux page tables and return a PTE pointer for
286 * a virtual address in a context.
287 * Returns true (1) if PTE was found, zero otherwise. The pointer to
288 * the PTE pointer is unmodified if PTE is not found.
291 get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp)
299 pgd = pgd_offset(mm, addr & PAGE_MASK);
301 pud = pud_offset(pgd, addr & PAGE_MASK);
302 if (pud && pud_present(*pud)) {
303 pmd = pmd_offset(pud, addr & PAGE_MASK);
304 if (pmd_present(*pmd)) {
305 pte = pte_offset_map(pmd, addr & PAGE_MASK);
311 /* XXX caller needs to do pte_unmap, yuck */
319 static int __change_page_attr_noflush(struct page *page, pgprot_t prot)
323 unsigned long address;
325 BUG_ON(PageHighMem(page));
326 address = (unsigned long)page_address(page);
328 if (v_block_mapped(address))
330 if (!get_pteptr(&init_mm, address, &kpte, &kpmd))
332 __set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0);
339 * Change the page attributes of an page in the linear mapping.
341 * THIS DOES NOTHING WITH BAT MAPPINGS, DEBUG USE ONLY
343 static int change_page_attr(struct page *page, int numpages, pgprot_t prot)
347 struct page *start = page;
349 local_irq_save(flags);
350 for (i = 0; i < numpages; i++, page++) {
351 err = __change_page_attr_noflush(page, prot);
356 local_irq_restore(flags);
357 flush_tlb_kernel_range((unsigned long)page_address(start),
358 (unsigned long)page_address(page));
362 void mark_initmem_nx(void)
364 struct page *page = virt_to_page(_sinittext);
365 unsigned long numpages = PFN_UP((unsigned long)_einittext) -
366 PFN_DOWN((unsigned long)_sinittext);
368 if (v_block_mapped((unsigned long)_stext) + 1)
369 mmu_mark_initmem_nx();
371 change_page_attr(page, numpages, PAGE_KERNEL);
374 #ifdef CONFIG_STRICT_KERNEL_RWX
375 void mark_rodata_ro(void)
378 unsigned long numpages;
380 if (v_block_mapped((unsigned long)_sinittext)) {
381 mmu_mark_rodata_ro();
385 page = virt_to_page(_stext);
386 numpages = PFN_UP((unsigned long)_etext) -
387 PFN_DOWN((unsigned long)_stext);
389 change_page_attr(page, numpages, PAGE_KERNEL_ROX);
391 * mark .rodata as read only. Use __init_begin rather than __end_rodata
392 * to cover NOTES and EXCEPTION_TABLE.
394 page = virt_to_page(__start_rodata);
395 numpages = PFN_UP((unsigned long)__init_begin) -
396 PFN_DOWN((unsigned long)__start_rodata);
398 change_page_attr(page, numpages, PAGE_KERNEL_RO);
400 // mark_initmem_nx() should have already run by now
405 #ifdef CONFIG_DEBUG_PAGEALLOC
406 void __kernel_map_pages(struct page *page, int numpages, int enable)
408 if (PageHighMem(page))
411 change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));
413 #endif /* CONFIG_DEBUG_PAGEALLOC */