698 lines
16 KiB
C
698 lines
16 KiB
C
/*
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* linux/arch/i386/mm/init.c
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*
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* Copyright (C) 1995 Linus Torvalds
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*
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* Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
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*/
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#include <linux/config.h>
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#include <linux/module.h>
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#include <linux/signal.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include <linux/ptrace.h>
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#include <linux/mman.h>
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#include <linux/mm.h>
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#include <linux/hugetlb.h>
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#include <linux/swap.h>
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#include <linux/smp.h>
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#include <linux/init.h>
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#include <linux/highmem.h>
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#include <linux/pagemap.h>
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#include <linux/bootmem.h>
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#include <linux/slab.h>
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#include <linux/proc_fs.h>
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#include <linux/efi.h>
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#include <asm/processor.h>
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#include <asm/system.h>
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#include <asm/uaccess.h>
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#include <asm/pgtable.h>
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#include <asm/dma.h>
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#include <asm/fixmap.h>
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#include <asm/e820.h>
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#include <asm/apic.h>
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#include <asm/tlb.h>
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#include <asm/tlbflush.h>
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#include <asm/sections.h>
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unsigned int __VMALLOC_RESERVE = 128 << 20;
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DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
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unsigned long highstart_pfn, highend_pfn;
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static int noinline do_test_wp_bit(void);
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/*
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* Creates a middle page table and puts a pointer to it in the
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* given global directory entry. This only returns the gd entry
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* in non-PAE compilation mode, since the middle layer is folded.
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*/
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static pmd_t * __init one_md_table_init(pgd_t *pgd)
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{
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pud_t *pud;
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pmd_t *pmd_table;
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#ifdef CONFIG_X86_PAE
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pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
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set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
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pud = pud_offset(pgd, 0);
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if (pmd_table != pmd_offset(pud, 0))
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BUG();
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#else
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pud = pud_offset(pgd, 0);
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pmd_table = pmd_offset(pud, 0);
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#endif
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return pmd_table;
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}
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/*
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* Create a page table and place a pointer to it in a middle page
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* directory entry.
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*/
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static pte_t * __init one_page_table_init(pmd_t *pmd)
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{
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if (pmd_none(*pmd)) {
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pte_t *page_table = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
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set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
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if (page_table != pte_offset_kernel(pmd, 0))
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BUG();
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return page_table;
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}
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return pte_offset_kernel(pmd, 0);
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}
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/*
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* This function initializes a certain range of kernel virtual memory
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* with new bootmem page tables, everywhere page tables are missing in
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* the given range.
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*/
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/*
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* NOTE: The pagetables are allocated contiguous on the physical space
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* so we can cache the place of the first one and move around without
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* checking the pgd every time.
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*/
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static void __init page_table_range_init (unsigned long start, unsigned long end, pgd_t *pgd_base)
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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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int pgd_idx, pmd_idx;
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unsigned long vaddr;
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vaddr = start;
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pgd_idx = pgd_index(vaddr);
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pmd_idx = pmd_index(vaddr);
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pgd = pgd_base + pgd_idx;
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for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
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if (pgd_none(*pgd))
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one_md_table_init(pgd);
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pud = pud_offset(pgd, vaddr);
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pmd = pmd_offset(pud, vaddr);
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for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); pmd++, pmd_idx++) {
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if (pmd_none(*pmd))
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one_page_table_init(pmd);
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vaddr += PMD_SIZE;
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}
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pmd_idx = 0;
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}
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}
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static inline int is_kernel_text(unsigned long addr)
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{
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if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
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return 1;
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return 0;
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}
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/*
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* This maps the physical memory to kernel virtual address space, a total
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* of max_low_pfn pages, by creating page tables starting from address
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* PAGE_OFFSET.
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*/
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static void __init kernel_physical_mapping_init(pgd_t *pgd_base)
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{
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unsigned long pfn;
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pgd_t *pgd;
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pmd_t *pmd;
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pte_t *pte;
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int pgd_idx, pmd_idx, pte_ofs;
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pgd_idx = pgd_index(PAGE_OFFSET);
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pgd = pgd_base + pgd_idx;
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pfn = 0;
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for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
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pmd = one_md_table_init(pgd);
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if (pfn >= max_low_pfn)
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continue;
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for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD && pfn < max_low_pfn; pmd++, pmd_idx++) {
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unsigned int address = pfn * PAGE_SIZE + PAGE_OFFSET;
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/* Map with big pages if possible, otherwise create normal page tables. */
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if (cpu_has_pse) {
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unsigned int address2 = (pfn + PTRS_PER_PTE - 1) * PAGE_SIZE + PAGE_OFFSET + PAGE_SIZE-1;
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if (is_kernel_text(address) || is_kernel_text(address2))
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set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE_EXEC));
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else
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set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE));
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pfn += PTRS_PER_PTE;
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} else {
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pte = one_page_table_init(pmd);
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for (pte_ofs = 0; pte_ofs < PTRS_PER_PTE && pfn < max_low_pfn; pte++, pfn++, pte_ofs++) {
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if (is_kernel_text(address))
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set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
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else
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set_pte(pte, pfn_pte(pfn, PAGE_KERNEL));
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}
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}
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}
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}
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}
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static inline int page_kills_ppro(unsigned long pagenr)
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{
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if (pagenr >= 0x70000 && pagenr <= 0x7003F)
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return 1;
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return 0;
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}
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extern int is_available_memory(efi_memory_desc_t *);
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int page_is_ram(unsigned long pagenr)
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{
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int i;
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unsigned long addr, end;
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if (efi_enabled) {
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efi_memory_desc_t *md;
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void *p;
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for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
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md = p;
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if (!is_available_memory(md))
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continue;
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addr = (md->phys_addr+PAGE_SIZE-1) >> PAGE_SHIFT;
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end = (md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT)) >> PAGE_SHIFT;
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if ((pagenr >= addr) && (pagenr < end))
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return 1;
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}
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return 0;
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}
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for (i = 0; i < e820.nr_map; i++) {
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if (e820.map[i].type != E820_RAM) /* not usable memory */
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continue;
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/*
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* !!!FIXME!!! Some BIOSen report areas as RAM that
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* are not. Notably the 640->1Mb area. We need a sanity
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* check here.
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*/
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addr = (e820.map[i].addr+PAGE_SIZE-1) >> PAGE_SHIFT;
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end = (e820.map[i].addr+e820.map[i].size) >> PAGE_SHIFT;
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if ((pagenr >= addr) && (pagenr < end))
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return 1;
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}
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return 0;
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}
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#ifdef CONFIG_HIGHMEM
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pte_t *kmap_pte;
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pgprot_t kmap_prot;
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#define kmap_get_fixmap_pte(vaddr) \
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pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), vaddr), (vaddr)), (vaddr))
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static void __init kmap_init(void)
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{
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unsigned long kmap_vstart;
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/* cache the first kmap pte */
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kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
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kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
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kmap_prot = PAGE_KERNEL;
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}
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static void __init permanent_kmaps_init(pgd_t *pgd_base)
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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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unsigned long vaddr;
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vaddr = PKMAP_BASE;
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page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
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pgd = swapper_pg_dir + pgd_index(vaddr);
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pud = pud_offset(pgd, vaddr);
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pmd = pmd_offset(pud, vaddr);
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pte = pte_offset_kernel(pmd, vaddr);
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pkmap_page_table = pte;
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}
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void __init one_highpage_init(struct page *page, int pfn, int bad_ppro)
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{
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if (page_is_ram(pfn) && !(bad_ppro && page_kills_ppro(pfn))) {
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ClearPageReserved(page);
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set_page_count(page, 1);
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__free_page(page);
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totalhigh_pages++;
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} else
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SetPageReserved(page);
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}
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#ifdef CONFIG_NUMA
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extern void set_highmem_pages_init(int);
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#else
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static void __init set_highmem_pages_init(int bad_ppro)
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{
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int pfn;
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for (pfn = highstart_pfn; pfn < highend_pfn; pfn++)
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one_highpage_init(pfn_to_page(pfn), pfn, bad_ppro);
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totalram_pages += totalhigh_pages;
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}
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#endif /* CONFIG_FLATMEM */
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#else
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#define kmap_init() do { } while (0)
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#define permanent_kmaps_init(pgd_base) do { } while (0)
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#define set_highmem_pages_init(bad_ppro) do { } while (0)
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#endif /* CONFIG_HIGHMEM */
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unsigned long long __PAGE_KERNEL = _PAGE_KERNEL;
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EXPORT_SYMBOL(__PAGE_KERNEL);
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unsigned long long __PAGE_KERNEL_EXEC = _PAGE_KERNEL_EXEC;
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#ifdef CONFIG_NUMA
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extern void __init remap_numa_kva(void);
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#else
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#define remap_numa_kva() do {} while (0)
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#endif
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static void __init pagetable_init (void)
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{
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unsigned long vaddr;
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pgd_t *pgd_base = swapper_pg_dir;
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#ifdef CONFIG_X86_PAE
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int i;
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/* Init entries of the first-level page table to the zero page */
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for (i = 0; i < PTRS_PER_PGD; i++)
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set_pgd(pgd_base + i, __pgd(__pa(empty_zero_page) | _PAGE_PRESENT));
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#endif
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/* Enable PSE if available */
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if (cpu_has_pse) {
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set_in_cr4(X86_CR4_PSE);
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}
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/* Enable PGE if available */
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if (cpu_has_pge) {
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set_in_cr4(X86_CR4_PGE);
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__PAGE_KERNEL |= _PAGE_GLOBAL;
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__PAGE_KERNEL_EXEC |= _PAGE_GLOBAL;
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}
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kernel_physical_mapping_init(pgd_base);
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remap_numa_kva();
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/*
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* Fixed mappings, only the page table structure has to be
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* created - mappings will be set by set_fixmap():
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*/
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vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
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page_table_range_init(vaddr, 0, pgd_base);
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permanent_kmaps_init(pgd_base);
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#ifdef CONFIG_X86_PAE
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/*
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* Add low memory identity-mappings - SMP needs it when
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* starting up on an AP from real-mode. In the non-PAE
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* case we already have these mappings through head.S.
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* All user-space mappings are explicitly cleared after
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* SMP startup.
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*/
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set_pgd(&pgd_base[0], pgd_base[USER_PTRS_PER_PGD]);
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#endif
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}
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#ifdef CONFIG_SOFTWARE_SUSPEND
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/*
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* Swap suspend & friends need this for resume because things like the intel-agp
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* driver might have split up a kernel 4MB mapping.
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*/
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char __nosavedata swsusp_pg_dir[PAGE_SIZE]
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__attribute__ ((aligned (PAGE_SIZE)));
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static inline void save_pg_dir(void)
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{
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memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
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}
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#else
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static inline void save_pg_dir(void)
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{
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}
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#endif
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void zap_low_mappings (void)
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{
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int i;
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save_pg_dir();
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/*
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* Zap initial low-memory mappings.
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*
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* Note that "pgd_clear()" doesn't do it for
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* us, because pgd_clear() is a no-op on i386.
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*/
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for (i = 0; i < USER_PTRS_PER_PGD; i++)
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#ifdef CONFIG_X86_PAE
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set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
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#else
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set_pgd(swapper_pg_dir+i, __pgd(0));
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#endif
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flush_tlb_all();
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}
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static int disable_nx __initdata = 0;
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u64 __supported_pte_mask __read_mostly = ~_PAGE_NX;
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/*
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* noexec = on|off
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*
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* Control non executable mappings.
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*
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* on Enable
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* off Disable
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*/
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void __init noexec_setup(const char *str)
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{
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if (!strncmp(str, "on",2) && cpu_has_nx) {
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__supported_pte_mask |= _PAGE_NX;
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disable_nx = 0;
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} else if (!strncmp(str,"off",3)) {
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disable_nx = 1;
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__supported_pte_mask &= ~_PAGE_NX;
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}
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}
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int nx_enabled = 0;
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#ifdef CONFIG_X86_PAE
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static void __init set_nx(void)
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{
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unsigned int v[4], l, h;
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if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
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cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
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if ((v[3] & (1 << 20)) && !disable_nx) {
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rdmsr(MSR_EFER, l, h);
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l |= EFER_NX;
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wrmsr(MSR_EFER, l, h);
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nx_enabled = 1;
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__supported_pte_mask |= _PAGE_NX;
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}
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}
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}
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/*
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* Enables/disables executability of a given kernel page and
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* returns the previous setting.
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*/
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int __init set_kernel_exec(unsigned long vaddr, int enable)
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{
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pte_t *pte;
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int ret = 1;
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if (!nx_enabled)
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goto out;
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pte = lookup_address(vaddr);
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BUG_ON(!pte);
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if (!pte_exec_kernel(*pte))
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ret = 0;
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if (enable)
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pte->pte_high &= ~(1 << (_PAGE_BIT_NX - 32));
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else
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pte->pte_high |= 1 << (_PAGE_BIT_NX - 32);
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__flush_tlb_all();
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out:
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return ret;
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}
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#endif
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/*
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* paging_init() sets up the page tables - note that the first 8MB are
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* already mapped by head.S.
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*
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* This routines also unmaps the page at virtual kernel address 0, so
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* that we can trap those pesky NULL-reference errors in the kernel.
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*/
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void __init paging_init(void)
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{
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#ifdef CONFIG_X86_PAE
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set_nx();
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if (nx_enabled)
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printk("NX (Execute Disable) protection: active\n");
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#endif
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pagetable_init();
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load_cr3(swapper_pg_dir);
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#ifdef CONFIG_X86_PAE
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/*
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* We will bail out later - printk doesn't work right now so
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* the user would just see a hanging kernel.
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*/
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if (cpu_has_pae)
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set_in_cr4(X86_CR4_PAE);
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#endif
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__flush_tlb_all();
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kmap_init();
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}
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/*
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* Test if the WP bit works in supervisor mode. It isn't supported on 386's
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* and also on some strange 486's (NexGen etc.). All 586+'s are OK. This
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* used to involve black magic jumps to work around some nasty CPU bugs,
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* but fortunately the switch to using exceptions got rid of all that.
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*/
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static void __init test_wp_bit(void)
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{
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printk("Checking if this processor honours the WP bit even in supervisor mode... ");
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/* Any page-aligned address will do, the test is non-destructive */
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__set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
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boot_cpu_data.wp_works_ok = do_test_wp_bit();
|
|
clear_fixmap(FIX_WP_TEST);
|
|
|
|
if (!boot_cpu_data.wp_works_ok) {
|
|
printk("No.\n");
|
|
#ifdef CONFIG_X86_WP_WORKS_OK
|
|
panic("This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
|
|
#endif
|
|
} else {
|
|
printk("Ok.\n");
|
|
}
|
|
}
|
|
|
|
static void __init set_max_mapnr_init(void)
|
|
{
|
|
#ifdef CONFIG_HIGHMEM
|
|
num_physpages = highend_pfn;
|
|
#else
|
|
num_physpages = max_low_pfn;
|
|
#endif
|
|
#ifdef CONFIG_FLATMEM
|
|
max_mapnr = num_physpages;
|
|
#endif
|
|
}
|
|
|
|
static struct kcore_list kcore_mem, kcore_vmalloc;
|
|
|
|
void __init mem_init(void)
|
|
{
|
|
extern int ppro_with_ram_bug(void);
|
|
int codesize, reservedpages, datasize, initsize;
|
|
int tmp;
|
|
int bad_ppro;
|
|
|
|
#ifdef CONFIG_FLATMEM
|
|
if (!mem_map)
|
|
BUG();
|
|
#endif
|
|
|
|
bad_ppro = ppro_with_ram_bug();
|
|
|
|
#ifdef CONFIG_HIGHMEM
|
|
/* check that fixmap and pkmap do not overlap */
|
|
if (PKMAP_BASE+LAST_PKMAP*PAGE_SIZE >= FIXADDR_START) {
|
|
printk(KERN_ERR "fixmap and kmap areas overlap - this will crash\n");
|
|
printk(KERN_ERR "pkstart: %lxh pkend: %lxh fixstart %lxh\n",
|
|
PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE, FIXADDR_START);
|
|
BUG();
|
|
}
|
|
#endif
|
|
|
|
set_max_mapnr_init();
|
|
|
|
#ifdef CONFIG_HIGHMEM
|
|
high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
|
|
#else
|
|
high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
|
|
#endif
|
|
|
|
/* this will put all low memory onto the freelists */
|
|
totalram_pages += free_all_bootmem();
|
|
|
|
reservedpages = 0;
|
|
for (tmp = 0; tmp < max_low_pfn; tmp++)
|
|
/*
|
|
* Only count reserved RAM pages
|
|
*/
|
|
if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
|
|
reservedpages++;
|
|
|
|
set_highmem_pages_init(bad_ppro);
|
|
|
|
codesize = (unsigned long) &_etext - (unsigned long) &_text;
|
|
datasize = (unsigned long) &_edata - (unsigned long) &_etext;
|
|
initsize = (unsigned long) &__init_end - (unsigned long) &__init_begin;
|
|
|
|
kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
|
|
kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
|
|
VMALLOC_END-VMALLOC_START);
|
|
|
|
printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data, %dk init, %ldk highmem)\n",
|
|
(unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
|
|
num_physpages << (PAGE_SHIFT-10),
|
|
codesize >> 10,
|
|
reservedpages << (PAGE_SHIFT-10),
|
|
datasize >> 10,
|
|
initsize >> 10,
|
|
(unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
|
|
);
|
|
|
|
#ifdef CONFIG_X86_PAE
|
|
if (!cpu_has_pae)
|
|
panic("cannot execute a PAE-enabled kernel on a PAE-less CPU!");
|
|
#endif
|
|
if (boot_cpu_data.wp_works_ok < 0)
|
|
test_wp_bit();
|
|
|
|
/*
|
|
* Subtle. SMP is doing it's boot stuff late (because it has to
|
|
* fork idle threads) - but it also needs low mappings for the
|
|
* protected-mode entry to work. We zap these entries only after
|
|
* the WP-bit has been tested.
|
|
*/
|
|
#ifndef CONFIG_SMP
|
|
zap_low_mappings();
|
|
#endif
|
|
}
|
|
|
|
kmem_cache_t *pgd_cache;
|
|
kmem_cache_t *pmd_cache;
|
|
|
|
void __init pgtable_cache_init(void)
|
|
{
|
|
if (PTRS_PER_PMD > 1) {
|
|
pmd_cache = kmem_cache_create("pmd",
|
|
PTRS_PER_PMD*sizeof(pmd_t),
|
|
PTRS_PER_PMD*sizeof(pmd_t),
|
|
0,
|
|
pmd_ctor,
|
|
NULL);
|
|
if (!pmd_cache)
|
|
panic("pgtable_cache_init(): cannot create pmd cache");
|
|
}
|
|
pgd_cache = kmem_cache_create("pgd",
|
|
PTRS_PER_PGD*sizeof(pgd_t),
|
|
PTRS_PER_PGD*sizeof(pgd_t),
|
|
0,
|
|
pgd_ctor,
|
|
PTRS_PER_PMD == 1 ? pgd_dtor : NULL);
|
|
if (!pgd_cache)
|
|
panic("pgtable_cache_init(): Cannot create pgd cache");
|
|
}
|
|
|
|
/*
|
|
* This function cannot be __init, since exceptions don't work in that
|
|
* section. Put this after the callers, so that it cannot be inlined.
|
|
*/
|
|
static int noinline do_test_wp_bit(void)
|
|
{
|
|
char tmp_reg;
|
|
int flag;
|
|
|
|
__asm__ __volatile__(
|
|
" movb %0,%1 \n"
|
|
"1: movb %1,%0 \n"
|
|
" xorl %2,%2 \n"
|
|
"2: \n"
|
|
".section __ex_table,\"a\"\n"
|
|
" .align 4 \n"
|
|
" .long 1b,2b \n"
|
|
".previous \n"
|
|
:"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
|
|
"=q" (tmp_reg),
|
|
"=r" (flag)
|
|
:"2" (1)
|
|
:"memory");
|
|
|
|
return flag;
|
|
}
|
|
|
|
void free_initmem(void)
|
|
{
|
|
unsigned long addr;
|
|
|
|
addr = (unsigned long)(&__init_begin);
|
|
for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) {
|
|
ClearPageReserved(virt_to_page(addr));
|
|
set_page_count(virt_to_page(addr), 1);
|
|
memset((void *)addr, 0xcc, PAGE_SIZE);
|
|
free_page(addr);
|
|
totalram_pages++;
|
|
}
|
|
printk (KERN_INFO "Freeing unused kernel memory: %dk freed\n", (__init_end - __init_begin) >> 10);
|
|
}
|
|
|
|
#ifdef CONFIG_BLK_DEV_INITRD
|
|
void free_initrd_mem(unsigned long start, unsigned long end)
|
|
{
|
|
if (start < end)
|
|
printk (KERN_INFO "Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
|
|
for (; start < end; start += PAGE_SIZE) {
|
|
ClearPageReserved(virt_to_page(start));
|
|
set_page_count(virt_to_page(start), 1);
|
|
free_page(start);
|
|
totalram_pages++;
|
|
}
|
|
}
|
|
#endif
|