823 lines
20 KiB
C
823 lines
20 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/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/pfn.h>
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#include <linux/poison.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/memory_hotplug.h>
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#include <linux/initrd.h>
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#include <linux/cpumask.h>
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#include <asm/asm.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/bugs.h>
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#include <asm/tlb.h>
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#include <asm/tlbflush.h>
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#include <asm/pgalloc.h>
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#include <asm/sections.h>
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#include <asm/paravirt.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 noinline int 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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if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
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pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
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paravirt_alloc_pd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT);
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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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BUG_ON(pmd_table != pmd_offset(pud, 0));
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}
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#endif
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pud = pud_offset(pgd, 0);
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pmd_table = pmd_offset(pud, 0);
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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_val(*pmd) & _PAGE_PRESENT)) {
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pte_t *page_table = NULL;
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#ifdef CONFIG_DEBUG_PAGEALLOC
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page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
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#endif
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if (!page_table) {
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page_table =
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(pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
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}
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paravirt_alloc_pt(&init_mm, __pa(page_table) >> PAGE_SHIFT);
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set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
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BUG_ON(page_table != pte_offset_kernel(pmd, 0));
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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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* 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
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page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
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{
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int pgd_idx, pmd_idx;
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unsigned long vaddr;
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pgd_t *pgd;
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pmd_t *pmd;
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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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pmd = one_md_table_init(pgd);
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pmd = pmd + pmd_index(vaddr);
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for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
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pmd++, pmd_idx++) {
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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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int pgd_idx, pmd_idx, pte_ofs;
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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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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;
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pmd_idx < PTRS_PER_PMD && pfn < max_low_pfn;
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pmd++, pmd_idx++) {
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unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;
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/*
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* Map with big pages if possible, otherwise
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* create normal page tables:
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*/
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if (cpu_has_pse) {
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unsigned int addr2;
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pgprot_t prot = PAGE_KERNEL_LARGE;
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addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
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PAGE_OFFSET + PAGE_SIZE-1;
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if (is_kernel_text(addr) ||
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is_kernel_text(addr2))
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prot = PAGE_KERNEL_LARGE_EXEC;
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set_pmd(pmd, pfn_pmd(pfn, prot));
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pfn += PTRS_PER_PTE;
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continue;
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}
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pte = one_page_table_init(pmd);
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for (pte_ofs = 0;
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pte_ofs < PTRS_PER_PTE && pfn < max_low_pfn;
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pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
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pgprot_t prot = PAGE_KERNEL;
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if (is_kernel_text(addr))
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prot = PAGE_KERNEL_EXEC;
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set_pte(pte, pfn_pte(pfn, prot));
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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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#ifdef CONFIG_HIGHMEM
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pte_t *kmap_pte;
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pgprot_t kmap_prot;
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static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr)
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{
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return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
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vaddr), vaddr), vaddr);
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}
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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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/*
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* Cache the first kmap pte:
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*/
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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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unsigned long vaddr;
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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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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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static void __meminit free_new_highpage(struct page *page)
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{
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init_page_count(page);
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__free_page(page);
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totalhigh_pages++;
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}
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void __init add_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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free_new_highpage(page);
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} else
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SetPageReserved(page);
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}
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static int __meminit
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add_one_highpage_hotplug(struct page *page, unsigned long pfn)
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{
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free_new_highpage(page);
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totalram_pages++;
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#ifdef CONFIG_FLATMEM
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max_mapnr = max(pfn, max_mapnr);
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#endif
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num_physpages++;
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return 0;
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}
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/*
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* Not currently handling the NUMA case.
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* Assuming single node and all memory that
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* has been added dynamically that would be
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* onlined here is in HIGHMEM.
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*/
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void __meminit online_page(struct page *page)
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{
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ClearPageReserved(page);
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add_one_highpage_hotplug(page, page_to_pfn(page));
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}
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#ifndef CONFIG_NUMA
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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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/*
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* Holes under sparsemem might not have no mem_map[]:
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*/
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if (pfn_valid(pfn))
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add_one_highpage_init(pfn_to_page(pfn), pfn, bad_ppro);
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}
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totalram_pages += totalhigh_pages;
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}
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#endif /* !CONFIG_NUMA */
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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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pteval_t __PAGE_KERNEL = _PAGE_KERNEL;
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EXPORT_SYMBOL(__PAGE_KERNEL);
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pteval_t __PAGE_KERNEL_EXEC = _PAGE_KERNEL_EXEC;
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void __init native_pagetable_setup_start(pgd_t *base)
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{
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#ifdef CONFIG_X86_PAE
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int i;
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/*
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* Init entries of the first-level page table to the
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* zero page, if they haven't already been set up.
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*
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* In a normal native boot, we'll be running on a
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* pagetable rooted in swapper_pg_dir, but not in PAE
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* mode, so this will end up clobbering the mappings
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* for the lower 24Mbytes of the address space,
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* without affecting the kernel address space.
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*/
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for (i = 0; i < USER_PTRS_PER_PGD; i++)
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set_pgd(&base[i],
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__pgd(__pa(empty_zero_page) | _PAGE_PRESENT));
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/* Make sure kernel address space is empty so that a pagetable
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will be allocated for it. */
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memset(&base[USER_PTRS_PER_PGD], 0,
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KERNEL_PGD_PTRS * sizeof(pgd_t));
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#else
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paravirt_alloc_pd(&init_mm, __pa(base) >> PAGE_SHIFT);
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#endif
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}
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void __init native_pagetable_setup_done(pgd_t *base)
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{
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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(&base[0], base[USER_PTRS_PER_PGD]);
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#endif
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}
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/*
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* Build a proper pagetable for the kernel mappings. Up until this
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* point, we've been running on some set of pagetables constructed by
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* the boot process.
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*
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* If we're booting on native hardware, this will be a pagetable
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* constructed in arch/i386/kernel/head.S, and not running in PAE mode
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* (even if we'll end up running in PAE). The root of the pagetable
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* will be swapper_pg_dir.
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*
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* If we're booting paravirtualized under a hypervisor, then there are
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* more options: we may already be running PAE, and the pagetable may
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* or may not be based in swapper_pg_dir. In any case,
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* paravirt_pagetable_setup_start() will set up swapper_pg_dir
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* appropriately for the rest of the initialization to work.
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*
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* In general, pagetable_init() assumes that the pagetable may already
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* be partially populated, and so it avoids stomping on any existing
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* mappings.
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*/
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static void __init pagetable_init(void)
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{
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pgd_t *pgd_base = swapper_pg_dir;
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unsigned long vaddr, end;
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paravirt_pagetable_setup_start(pgd_base);
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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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/* 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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early_ioremap_clear();
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vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
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end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
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page_table_range_init(vaddr, end, pgd_base);
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early_ioremap_reset();
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permanent_kmaps_init(pgd_base);
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paravirt_pagetable_setup_done(pgd_base);
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}
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#ifdef CONFIG_ACPI_SLEEP
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/*
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* ACPI suspend needs 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 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 /* !CONFIG_ACPI_SLEEP */
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static inline void save_pg_dir(void)
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{
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}
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#endif /* !CONFIG_ACPI_SLEEP */
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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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}
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flush_tlb_all();
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}
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|
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int nx_enabled;
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|
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pteval_t __supported_pte_mask __read_mostly = ~_PAGE_NX;
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EXPORT_SYMBOL_GPL(__supported_pte_mask);
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#ifdef CONFIG_X86_PAE
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|
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static int disable_nx __initdata;
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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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static int __init noexec_setup(char *str)
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{
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if (!str || !strcmp(str, "on")) {
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if (cpu_has_nx) {
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__supported_pte_mask |= _PAGE_NX;
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disable_nx = 0;
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}
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} else {
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if (!strcmp(str, "off")) {
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disable_nx = 1;
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__supported_pte_mask &= ~_PAGE_NX;
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} else {
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return -EINVAL;
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}
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}
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|
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return 0;
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}
|
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early_param("noexec", noexec_setup);
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|
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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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|
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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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|
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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;
|
|
wrmsr(MSR_EFER, l, h);
|
|
nx_enabled = 1;
|
|
__supported_pte_mask |= _PAGE_NX;
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* paging_init() sets up the page tables - note that the first 8MB are
|
|
* already mapped by head.S.
|
|
*
|
|
* This routines also unmaps the page at virtual kernel address 0, so
|
|
* that we can trap those pesky NULL-reference errors in the kernel.
|
|
*/
|
|
void __init paging_init(void)
|
|
{
|
|
#ifdef CONFIG_X86_PAE
|
|
set_nx();
|
|
if (nx_enabled)
|
|
printk(KERN_INFO "NX (Execute Disable) protection: active\n");
|
|
#endif
|
|
pagetable_init();
|
|
|
|
load_cr3(swapper_pg_dir);
|
|
|
|
#ifdef CONFIG_X86_PAE
|
|
/*
|
|
* We will bail out later - printk doesn't work right now so
|
|
* the user would just see a hanging kernel.
|
|
*/
|
|
if (cpu_has_pae)
|
|
set_in_cr4(X86_CR4_PAE);
|
|
#endif
|
|
__flush_tlb_all();
|
|
|
|
kmap_init();
|
|
}
|
|
|
|
/*
|
|
* Test if the WP bit works in supervisor mode. It isn't supported on 386's
|
|
* and also on some strange 486's (NexGen etc.). All 586+'s are OK. This
|
|
* used to involve black magic jumps to work around some nasty CPU bugs,
|
|
* but fortunately the switch to using exceptions got rid of all that.
|
|
*/
|
|
static void __init test_wp_bit(void)
|
|
{
|
|
printk(KERN_INFO
|
|
"Checking if this processor honours the WP bit even in supervisor mode...");
|
|
|
|
/* Any page-aligned address will do, the test is non-destructive */
|
|
__set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
|
|
boot_cpu_data.wp_works_ok = do_test_wp_bit();
|
|
clear_fixmap(FIX_WP_TEST);
|
|
|
|
if (!boot_cpu_data.wp_works_ok) {
|
|
printk(KERN_CONT "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(KERN_CONT "Ok.\n");
|
|
}
|
|
}
|
|
|
|
static struct kcore_list kcore_mem, kcore_vmalloc;
|
|
|
|
void __init mem_init(void)
|
|
{
|
|
int codesize, reservedpages, datasize, initsize;
|
|
int tmp, bad_ppro;
|
|
|
|
#ifdef CONFIG_FLATMEM
|
|
BUG_ON(!mem_map);
|
|
#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
|
|
/* 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))
|
|
);
|
|
|
|
#if 1 /* double-sanity-check paranoia */
|
|
printk(KERN_INFO "virtual kernel memory layout:\n"
|
|
" fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n"
|
|
#ifdef CONFIG_HIGHMEM
|
|
" pkmap : 0x%08lx - 0x%08lx (%4ld kB)\n"
|
|
#endif
|
|
" vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n"
|
|
" lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n"
|
|
" .init : 0x%08lx - 0x%08lx (%4ld kB)\n"
|
|
" .data : 0x%08lx - 0x%08lx (%4ld kB)\n"
|
|
" .text : 0x%08lx - 0x%08lx (%4ld kB)\n",
|
|
FIXADDR_START, FIXADDR_TOP,
|
|
(FIXADDR_TOP - FIXADDR_START) >> 10,
|
|
|
|
#ifdef CONFIG_HIGHMEM
|
|
PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
|
|
(LAST_PKMAP*PAGE_SIZE) >> 10,
|
|
#endif
|
|
|
|
VMALLOC_START, VMALLOC_END,
|
|
(VMALLOC_END - VMALLOC_START) >> 20,
|
|
|
|
(unsigned long)__va(0), (unsigned long)high_memory,
|
|
((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,
|
|
|
|
(unsigned long)&__init_begin, (unsigned long)&__init_end,
|
|
((unsigned long)&__init_end -
|
|
(unsigned long)&__init_begin) >> 10,
|
|
|
|
(unsigned long)&_etext, (unsigned long)&_edata,
|
|
((unsigned long)&_edata - (unsigned long)&_etext) >> 10,
|
|
|
|
(unsigned long)&_text, (unsigned long)&_etext,
|
|
((unsigned long)&_etext - (unsigned long)&_text) >> 10);
|
|
|
|
#ifdef CONFIG_HIGHMEM
|
|
BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START);
|
|
BUG_ON(VMALLOC_END > PKMAP_BASE);
|
|
#endif
|
|
BUG_ON(VMALLOC_START > VMALLOC_END);
|
|
BUG_ON((unsigned long)high_memory > VMALLOC_START);
|
|
#endif /* double-sanity-check paranoia */
|
|
|
|
#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
|
|
}
|
|
|
|
#ifdef CONFIG_MEMORY_HOTPLUG
|
|
int arch_add_memory(int nid, u64 start, u64 size)
|
|
{
|
|
struct pglist_data *pgdata = NODE_DATA(nid);
|
|
struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM;
|
|
unsigned long start_pfn = start >> PAGE_SHIFT;
|
|
unsigned long nr_pages = size >> PAGE_SHIFT;
|
|
|
|
return __add_pages(zone, start_pfn, nr_pages);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* 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 noinline int 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"
|
|
_ASM_EXTABLE(1b,2b)
|
|
:"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
|
|
"=q" (tmp_reg),
|
|
"=r" (flag)
|
|
:"2" (1)
|
|
:"memory");
|
|
|
|
return flag;
|
|
}
|
|
|
|
#ifdef CONFIG_DEBUG_RODATA
|
|
const int rodata_test_data = 0xC3;
|
|
EXPORT_SYMBOL_GPL(rodata_test_data);
|
|
|
|
void mark_rodata_ro(void)
|
|
{
|
|
unsigned long start = PFN_ALIGN(_text);
|
|
unsigned long size = PFN_ALIGN(_etext) - start;
|
|
|
|
#ifndef CONFIG_KPROBES
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
/* It must still be possible to apply SMP alternatives. */
|
|
if (num_possible_cpus() <= 1)
|
|
#endif
|
|
{
|
|
set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
|
|
printk(KERN_INFO "Write protecting the kernel text: %luk\n",
|
|
size >> 10);
|
|
|
|
#ifdef CONFIG_CPA_DEBUG
|
|
printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
|
|
start, start+size);
|
|
set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);
|
|
|
|
printk(KERN_INFO "Testing CPA: write protecting again\n");
|
|
set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
|
|
#endif
|
|
}
|
|
#endif
|
|
start += size;
|
|
size = (unsigned long)__end_rodata - start;
|
|
set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
|
|
printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
|
|
size >> 10);
|
|
rodata_test();
|
|
|
|
#ifdef CONFIG_CPA_DEBUG
|
|
printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size);
|
|
set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
|
|
|
|
printk(KERN_INFO "Testing CPA: write protecting again\n");
|
|
set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
|
|
#endif
|
|
}
|
|
#endif
|
|
|
|
void free_init_pages(char *what, unsigned long begin, unsigned long end)
|
|
{
|
|
#ifdef CONFIG_DEBUG_PAGEALLOC
|
|
/*
|
|
* If debugging page accesses then do not free this memory but
|
|
* mark them not present - any buggy init-section access will
|
|
* create a kernel page fault:
|
|
*/
|
|
printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n",
|
|
begin, PAGE_ALIGN(end));
|
|
set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
|
|
#else
|
|
unsigned long addr;
|
|
|
|
/*
|
|
* We just marked the kernel text read only above, now that
|
|
* we are going to free part of that, we need to make that
|
|
* writeable first.
|
|
*/
|
|
set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
|
|
|
|
for (addr = begin; addr < end; addr += PAGE_SIZE) {
|
|
ClearPageReserved(virt_to_page(addr));
|
|
init_page_count(virt_to_page(addr));
|
|
memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
|
|
free_page(addr);
|
|
totalram_pages++;
|
|
}
|
|
printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
|
|
#endif
|
|
}
|
|
|
|
void free_initmem(void)
|
|
{
|
|
free_init_pages("unused kernel memory",
|
|
(unsigned long)(&__init_begin),
|
|
(unsigned long)(&__init_end));
|
|
}
|
|
|
|
#ifdef CONFIG_BLK_DEV_INITRD
|
|
void free_initrd_mem(unsigned long start, unsigned long end)
|
|
{
|
|
free_init_pages("initrd memory", start, end);
|
|
}
|
|
#endif
|