354 lines
8.2 KiB
C
354 lines
8.2 KiB
C
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/*
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* handle transition of Linux booting another kernel
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* Copyright (C) 2002-2005 Eric Biederman <ebiederm@xmission.com>
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*
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* This source code is licensed under the GNU General Public License,
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* Version 2. See the file COPYING for more details.
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*/
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#include <linux/mm.h>
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#include <linux/kexec.h>
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#include <linux/string.h>
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#include <linux/reboot.h>
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#include <linux/numa.h>
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#include <linux/ftrace.h>
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#include <linux/io.h>
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#include <linux/suspend.h>
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#include <asm/pgtable.h>
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#include <asm/tlbflush.h>
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#include <asm/mmu_context.h>
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static int init_one_level2_page(struct kimage *image, pgd_t *pgd,
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unsigned long addr)
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{
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pud_t *pud;
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pmd_t *pmd;
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struct page *page;
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int result = -ENOMEM;
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addr &= PMD_MASK;
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pgd += pgd_index(addr);
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if (!pgd_present(*pgd)) {
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page = kimage_alloc_control_pages(image, 0);
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if (!page)
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goto out;
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pud = (pud_t *)page_address(page);
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memset(pud, 0, PAGE_SIZE);
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set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
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}
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pud = pud_offset(pgd, addr);
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if (!pud_present(*pud)) {
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page = kimage_alloc_control_pages(image, 0);
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if (!page)
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goto out;
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pmd = (pmd_t *)page_address(page);
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memset(pmd, 0, PAGE_SIZE);
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set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
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}
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pmd = pmd_offset(pud, addr);
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if (!pmd_present(*pmd))
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set_pmd(pmd, __pmd(addr | __PAGE_KERNEL_LARGE_EXEC));
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result = 0;
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out:
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return result;
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}
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static void init_level2_page(pmd_t *level2p, unsigned long addr)
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{
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unsigned long end_addr;
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addr &= PAGE_MASK;
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end_addr = addr + PUD_SIZE;
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while (addr < end_addr) {
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set_pmd(level2p++, __pmd(addr | __PAGE_KERNEL_LARGE_EXEC));
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addr += PMD_SIZE;
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}
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}
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static int init_level3_page(struct kimage *image, pud_t *level3p,
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unsigned long addr, unsigned long last_addr)
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{
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unsigned long end_addr;
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int result;
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result = 0;
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addr &= PAGE_MASK;
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end_addr = addr + PGDIR_SIZE;
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while ((addr < last_addr) && (addr < end_addr)) {
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struct page *page;
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pmd_t *level2p;
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page = kimage_alloc_control_pages(image, 0);
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if (!page) {
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result = -ENOMEM;
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goto out;
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}
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level2p = (pmd_t *)page_address(page);
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init_level2_page(level2p, addr);
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set_pud(level3p++, __pud(__pa(level2p) | _KERNPG_TABLE));
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addr += PUD_SIZE;
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}
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/* clear the unused entries */
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while (addr < end_addr) {
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pud_clear(level3p++);
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addr += PUD_SIZE;
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}
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out:
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return result;
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}
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static int init_level4_page(struct kimage *image, pgd_t *level4p,
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unsigned long addr, unsigned long last_addr)
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{
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unsigned long end_addr;
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int result;
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result = 0;
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addr &= PAGE_MASK;
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end_addr = addr + (PTRS_PER_PGD * PGDIR_SIZE);
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while ((addr < last_addr) && (addr < end_addr)) {
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struct page *page;
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pud_t *level3p;
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page = kimage_alloc_control_pages(image, 0);
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if (!page) {
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result = -ENOMEM;
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goto out;
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}
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level3p = (pud_t *)page_address(page);
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result = init_level3_page(image, level3p, addr, last_addr);
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if (result)
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goto out;
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set_pgd(level4p++, __pgd(__pa(level3p) | _KERNPG_TABLE));
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addr += PGDIR_SIZE;
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}
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/* clear the unused entries */
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while (addr < end_addr) {
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pgd_clear(level4p++);
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addr += PGDIR_SIZE;
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}
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out:
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return result;
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}
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static void free_transition_pgtable(struct kimage *image)
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{
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free_page((unsigned long)image->arch.pud);
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free_page((unsigned long)image->arch.pmd);
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free_page((unsigned long)image->arch.pte);
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}
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static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
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{
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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, paddr;
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int result = -ENOMEM;
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vaddr = (unsigned long)relocate_kernel;
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paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE);
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pgd += pgd_index(vaddr);
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if (!pgd_present(*pgd)) {
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pud = (pud_t *)get_zeroed_page(GFP_KERNEL);
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if (!pud)
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goto err;
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image->arch.pud = pud;
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set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
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}
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pud = pud_offset(pgd, vaddr);
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if (!pud_present(*pud)) {
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pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL);
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if (!pmd)
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goto err;
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image->arch.pmd = pmd;
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set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
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}
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pmd = pmd_offset(pud, vaddr);
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if (!pmd_present(*pmd)) {
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pte = (pte_t *)get_zeroed_page(GFP_KERNEL);
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if (!pte)
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goto err;
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image->arch.pte = pte;
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set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));
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}
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pte = pte_offset_kernel(pmd, vaddr);
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set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
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return 0;
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err:
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free_transition_pgtable(image);
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return result;
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}
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static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
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{
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pgd_t *level4p;
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int result;
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level4p = (pgd_t *)__va(start_pgtable);
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result = init_level4_page(image, level4p, 0, max_pfn << PAGE_SHIFT);
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if (result)
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return result;
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/*
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* image->start may be outside 0 ~ max_pfn, for example when
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* jump back to original kernel from kexeced kernel
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*/
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result = init_one_level2_page(image, level4p, image->start);
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if (result)
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return result;
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return init_transition_pgtable(image, level4p);
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}
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static void set_idt(void *newidt, u16 limit)
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{
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struct desc_ptr curidt;
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/* x86-64 supports unaliged loads & stores */
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curidt.size = limit;
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curidt.address = (unsigned long)newidt;
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__asm__ __volatile__ (
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"lidtq %0\n"
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: : "m" (curidt)
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);
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};
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static void set_gdt(void *newgdt, u16 limit)
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{
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struct desc_ptr curgdt;
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/* x86-64 supports unaligned loads & stores */
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curgdt.size = limit;
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curgdt.address = (unsigned long)newgdt;
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__asm__ __volatile__ (
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"lgdtq %0\n"
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: : "m" (curgdt)
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);
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};
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static void load_segments(void)
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{
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__asm__ __volatile__ (
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"\tmovl %0,%%ds\n"
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"\tmovl %0,%%es\n"
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"\tmovl %0,%%ss\n"
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"\tmovl %0,%%fs\n"
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"\tmovl %0,%%gs\n"
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: : "a" (__KERNEL_DS) : "memory"
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);
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}
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int machine_kexec_prepare(struct kimage *image)
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{
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unsigned long start_pgtable;
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int result;
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/* Calculate the offsets */
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start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT;
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/* Setup the identity mapped 64bit page table */
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result = init_pgtable(image, start_pgtable);
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if (result)
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return result;
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return 0;
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}
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void machine_kexec_cleanup(struct kimage *image)
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{
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free_transition_pgtable(image);
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}
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/*
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* Do not allocate memory (or fail in any way) in machine_kexec().
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* We are past the point of no return, committed to rebooting now.
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*/
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void machine_kexec(struct kimage *image)
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{
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unsigned long page_list[PAGES_NR];
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void *control_page;
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int save_ftrace_enabled;
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#ifdef CONFIG_KEXEC_JUMP
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if (image->preserve_context)
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save_processor_state();
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#endif
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save_ftrace_enabled = __ftrace_enabled_save();
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/* Interrupts aren't acceptable while we reboot */
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local_irq_disable();
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if (image->preserve_context) {
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#ifdef CONFIG_X86_IO_APIC
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/*
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* We need to put APICs in legacy mode so that we can
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* get timer interrupts in second kernel. kexec/kdump
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* paths already have calls to disable_IO_APIC() in
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* one form or other. kexec jump path also need
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* one.
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*/
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disable_IO_APIC();
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#endif
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}
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control_page = page_address(image->control_code_page) + PAGE_SIZE;
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memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
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page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page);
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page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
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page_list[PA_TABLE_PAGE] =
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(unsigned long)__pa(page_address(image->control_code_page));
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if (image->type == KEXEC_TYPE_DEFAULT)
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page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
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<< PAGE_SHIFT);
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/*
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* The segment registers are funny things, they have both a
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* visible and an invisible part. Whenever the visible part is
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* set to a specific selector, the invisible part is loaded
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* with from a table in memory. At no other time is the
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* descriptor table in memory accessed.
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*
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* I take advantage of this here by force loading the
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* segments, before I zap the gdt with an invalid value.
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*/
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load_segments();
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/*
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* The gdt & idt are now invalid.
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* If you want to load them you must set up your own idt & gdt.
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*/
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set_gdt(phys_to_virt(0), 0);
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set_idt(phys_to_virt(0), 0);
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/* now call it */
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image->start = relocate_kernel((unsigned long)image->head,
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(unsigned long)page_list,
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image->start,
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image->preserve_context);
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#ifdef CONFIG_KEXEC_JUMP
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if (image->preserve_context)
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restore_processor_state();
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#endif
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__ftrace_enabled_restore(save_ftrace_enabled);
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}
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void arch_crash_save_vmcoreinfo(void)
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{
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VMCOREINFO_SYMBOL(phys_base);
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VMCOREINFO_SYMBOL(init_level4_pgt);
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#ifdef CONFIG_NUMA
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VMCOREINFO_SYMBOL(node_data);
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VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
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#endif
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}
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