arch/x86/kernel/machine_kexec_64.c - third_party/linux - Git at Google

 /*
  * handle transition of Linux booting another kernel
  * Copyright (C) 2002-2005 Eric Biederman  <ebiederm@xmission.com>
  *
  * This source code is licensed under the GNU General Public License,
  * Version 2.  See the file COPYING for more details.
  */

 #include <linux/mm.h>
 #include <linux/kexec.h>
 #include <linux/string.h>
 #include <linux/gfp.h>
 #include <linux/reboot.h>
 #include <linux/numa.h>
 #include <linux/ftrace.h>
 #include <linux/io.h>
 #include <linux/suspend.h>

 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
 #include <asm/mmu_context.h>
 #include <asm/debugreg.h>

 static int init_one_level2_page(struct kimage *image, pgd_t *pgd,
 				unsigned long addr)
 {
 	pud_t *pud;
 	pmd_t *pmd;
 	struct page *page;
 	int result = -ENOMEM;

 	addr &= PMD_MASK;
 	pgd += pgd_index(addr);
 	if (!pgd_present(*pgd)) {
 		page = kimage_alloc_control_pages(image, 0);
 		if (!page)
 			goto out;
 		pud = (pud_t *)page_address(page);
 		clear_page(pud);
 		set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
 	}
 	pud = pud_offset(pgd, addr);
 	if (!pud_present(*pud)) {
 		page = kimage_alloc_control_pages(image, 0);
 		if (!page)
 			goto out;
 		pmd = (pmd_t *)page_address(page);
 		clear_page(pmd);
 		set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
 	}
 	pmd = pmd_offset(pud, addr);
 	if (!pmd_present(*pmd))
 		set_pmd(pmd, __pmd(addr | __PAGE_KERNEL_LARGE_EXEC));
 	result = 0;
 out:
 	return result;
 }

 static void init_level2_page(pmd_t *level2p, unsigned long addr)
 {
 	unsigned long end_addr;

 	addr &= PAGE_MASK;
 	end_addr = addr + PUD_SIZE;
 	while (addr < end_addr) {
 		set_pmd(level2p++, __pmd(addr | __PAGE_KERNEL_LARGE_EXEC));
 		addr += PMD_SIZE;
 	}
 }

 static int init_level3_page(struct kimage *image, pud_t *level3p,
 				unsigned long addr, unsigned long last_addr)
 {
 	unsigned long end_addr;
 	int result;

 	result = 0;
 	addr &= PAGE_MASK;
 	end_addr = addr + PGDIR_SIZE;
 	while ((addr < last_addr) && (addr < end_addr)) {
 		struct page *page;
 		pmd_t *level2p;

 		page = kimage_alloc_control_pages(image, 0);
 		if (!page) {
 			result = -ENOMEM;
 			goto out;
 		}
 		level2p = (pmd_t *)page_address(page);
 		init_level2_page(level2p, addr);
 		set_pud(level3p++, __pud(__pa(level2p) | _KERNPG_TABLE));
 		addr += PUD_SIZE;
 	}
 	/* clear the unused entries */
 	while (addr < end_addr) {
 		pud_clear(level3p++);
 		addr += PUD_SIZE;
 	}
 out:
 	return result;
 }


 static int init_level4_page(struct kimage *image, pgd_t *level4p,
 				unsigned long addr, unsigned long last_addr)
 {
 	unsigned long end_addr;
 	int result;

 	result = 0;
 	addr &= PAGE_MASK;
 	end_addr = addr + (PTRS_PER_PGD * PGDIR_SIZE);
 	while ((addr < last_addr) && (addr < end_addr)) {
 		struct page *page;
 		pud_t *level3p;

 		page = kimage_alloc_control_pages(image, 0);
 		if (!page) {
 			result = -ENOMEM;
 			goto out;
 		}
 		level3p = (pud_t *)page_address(page);
 		result = init_level3_page(image, level3p, addr, last_addr);
 		if (result)
 			goto out;
 		set_pgd(level4p++, __pgd(__pa(level3p) | _KERNPG_TABLE));
 		addr += PGDIR_SIZE;
 	}
 	/* clear the unused entries */
 	while (addr < end_addr) {
 		pgd_clear(level4p++);
 		addr += PGDIR_SIZE;
 	}
 out:
 	return result;
 }

 static void free_transition_pgtable(struct kimage *image)
 {
 	free_page((unsigned long)image->arch.pud);
 	free_page((unsigned long)image->arch.pmd);
 	free_page((unsigned long)image->arch.pte);
 }

 static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
 {
 	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *pte;
 	unsigned long vaddr, paddr;
 	int result = -ENOMEM;

 	vaddr = (unsigned long)relocate_kernel;
 	paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE);
 	pgd += pgd_index(vaddr);
 	if (!pgd_present(*pgd)) {
 		pud = (pud_t *)get_zeroed_page(GFP_KERNEL);
 		if (!pud)
 			goto err;
 		image->arch.pud = pud;
 		set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
 	}
 	pud = pud_offset(pgd, vaddr);
 	if (!pud_present(*pud)) {
 		pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL);
 		if (!pmd)
 			goto err;
 		image->arch.pmd = pmd;
 		set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
 	}
 	pmd = pmd_offset(pud, vaddr);
 	if (!pmd_present(*pmd)) {
 		pte = (pte_t *)get_zeroed_page(GFP_KERNEL);
 		if (!pte)
 			goto err;
 		image->arch.pte = pte;
 		set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));
 	}
 	pte = pte_offset_kernel(pmd, vaddr);
 	set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
 	return 0;
 err:
 	free_transition_pgtable(image);
 	return result;
 }


 static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
 {
 	pgd_t *level4p;
 	int result;
 	level4p = (pgd_t *)__va(start_pgtable);
 	result = init_level4_page(image, level4p, 0, max_pfn << PAGE_SHIFT);
 	if (result)
 		return result;
 	/*
 	 * image->start may be outside 0 ~ max_pfn, for example when
 	 * jump back to original kernel from kexeced kernel
 	 */
 	result = init_one_level2_page(image, level4p, image->start);
 	if (result)
 		return result;
 	return init_transition_pgtable(image, level4p);
 }

 static void set_idt(void *newidt, u16 limit)
 {
 	struct desc_ptr curidt;

 	/* x86-64 supports unaliged loads & stores */
 	curidt.size    = limit;
 	curidt.address = (unsigned long)newidt;

 	__asm__ __volatile__ (
 		"lidtq %0\n"
 		: : "m" (curidt)
 		);
 };


 static void set_gdt(void *newgdt, u16 limit)
 {
 	struct desc_ptr curgdt;

 	/* x86-64 supports unaligned loads & stores */
 	curgdt.size    = limit;
 	curgdt.address = (unsigned long)newgdt;

 	__asm__ __volatile__ (
 		"lgdtq %0\n"
 		: : "m" (curgdt)
 		);
 };

 static void load_segments(void)
 {
 	__asm__ __volatile__ (
 		"\tmovl %0,%%ds\n"
 		"\tmovl %0,%%es\n"
 		"\tmovl %0,%%ss\n"
 		"\tmovl %0,%%fs\n"
 		"\tmovl %0,%%gs\n"
 		: : "a" (__KERNEL_DS) : "memory"
 		);
 }

 int machine_kexec_prepare(struct kimage *image)
 {
 	unsigned long start_pgtable;
 	int result;

 	/* Calculate the offsets */
 	start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT;

 	/* Setup the identity mapped 64bit page table */
 	result = init_pgtable(image, start_pgtable);
 	if (result)
 		return result;

 	return 0;
 }

 void machine_kexec_cleanup(struct kimage *image)
 {
 	free_transition_pgtable(image);
 }

 /*
  * Do not allocate memory (or fail in any way) in machine_kexec().
  * We are past the point of no return, committed to rebooting now.
  */
 void machine_kexec(struct kimage *image)
 {
 	unsigned long page_list[PAGES_NR];
 	void *control_page;
 	int save_ftrace_enabled;

 #ifdef CONFIG_KEXEC_JUMP
 	if (image->preserve_context)
 		save_processor_state();
 #endif

 	save_ftrace_enabled = __ftrace_enabled_save();

 	/* Interrupts aren't acceptable while we reboot */
 	local_irq_disable();
 	hw_breakpoint_disable();

 	if (image->preserve_context) {
 #ifdef CONFIG_X86_IO_APIC
 		/*
 		 * We need to put APICs in legacy mode so that we can
 		 * get timer interrupts in second kernel. kexec/kdump
 		 * paths already have calls to disable_IO_APIC() in
 		 * one form or other. kexec jump path also need
 		 * one.
 		 */
 		disable_IO_APIC();
 #endif
 	}

 	control_page = page_address(image->control_code_page) + PAGE_SIZE;
 	memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);

 	page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page);
 	page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
 	page_list[PA_TABLE_PAGE] =
 	  (unsigned long)__pa(page_address(image->control_code_page));

 	if (image->type == KEXEC_TYPE_DEFAULT)
 		page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
 						<< PAGE_SHIFT);

 	/*
 	 * The segment registers are funny things, they have both a
 	 * visible and an invisible part.  Whenever the visible part is
 	 * set to a specific selector, the invisible part is loaded
 	 * with from a table in memory.  At no other time is the
 	 * descriptor table in memory accessed.
 	 *
 	 * I take advantage of this here by force loading the
 	 * segments, before I zap the gdt with an invalid value.
 	 */
 	load_segments();
 	/*
 	 * The gdt & idt are now invalid.
 	 * If you want to load them you must set up your own idt & gdt.
 	 */
 	set_gdt(phys_to_virt(0), 0);
 	set_idt(phys_to_virt(0), 0);

 	/* now call it */
 	image->start = relocate_kernel((unsigned long)image->head,
 				       (unsigned long)page_list,
 				       image->start,
 				       image->preserve_context);

 #ifdef CONFIG_KEXEC_JUMP
 	if (image->preserve_context)
 		restore_processor_state();
 #endif

 	__ftrace_enabled_restore(save_ftrace_enabled);
 }

 void arch_crash_save_vmcoreinfo(void)
 {
 	VMCOREINFO_SYMBOL(phys_base);
 	VMCOREINFO_SYMBOL(init_level4_pgt);

 #ifdef CONFIG_NUMA
 	VMCOREINFO_SYMBOL(node_data);
 	VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
 #endif
 }
	/*
	* handle transition of Linux booting another kernel
	* Copyright (C) 2002-2005 Eric Biederman <ebiederm@xmission.com>
	*
	* This source code is licensed under the GNU General Public License,
	* Version 2. See the file COPYING for more details.
	*/

	#include <linux/mm.h>
	#include <linux/kexec.h>
	#include <linux/string.h>
	#include <linux/gfp.h>
	#include <linux/reboot.h>
	#include <linux/numa.h>
	#include <linux/ftrace.h>
	#include <linux/io.h>
	#include <linux/suspend.h>

	#include <asm/pgtable.h>
	#include <asm/tlbflush.h>
	#include <asm/mmu_context.h>
	#include <asm/debugreg.h>

	static int init_one_level2_page(struct kimage image, pgd_t pgd,
	unsigned long addr)
	{
	pud_t *pud;
	pmd_t *pmd;
	struct page *page;
	int result = -ENOMEM;

	addr &= PMD_MASK;
	pgd += pgd_index(addr);
	if (!pgd_present(*pgd)) {
	page = kimage_alloc_control_pages(image, 0);
	if (!page)
	goto out;
	pud = (pud_t *)page_address(page);
	clear_page(pud);
	set_pgd(pgd, __pgd(__pa(pud) \| _KERNPG_TABLE));
	}
	pud = pud_offset(pgd, addr);
	if (!pud_present(*pud)) {
	page = kimage_alloc_control_pages(image, 0);
	if (!page)
	goto out;
	pmd = (pmd_t *)page_address(page);
	clear_page(pmd);
	set_pud(pud, __pud(__pa(pmd) \| _KERNPG_TABLE));
	}
	pmd = pmd_offset(pud, addr);
	if (!pmd_present(*pmd))
	set_pmd(pmd, __pmd(addr \| __PAGE_KERNEL_LARGE_EXEC));
	result = 0;
	out:
	return result;
	}

	static void init_level2_page(pmd_t *level2p, unsigned long addr)
	{
	unsigned long end_addr;

	addr &= PAGE_MASK;
	end_addr = addr + PUD_SIZE;
	while (addr < end_addr) {
	set_pmd(level2p++, __pmd(addr \| __PAGE_KERNEL_LARGE_EXEC));
	addr += PMD_SIZE;
	}
	}

	static int init_level3_page(struct kimage image, pud_t level3p,
	unsigned long addr, unsigned long last_addr)
	{
	unsigned long end_addr;
	int result;

	result = 0;
	addr &= PAGE_MASK;
	end_addr = addr + PGDIR_SIZE;
	while ((addr < last_addr) && (addr < end_addr)) {
	struct page *page;
	pmd_t *level2p;

	page = kimage_alloc_control_pages(image, 0);
	if (!page) {
	result = -ENOMEM;
	goto out;
	}
	level2p = (pmd_t *)page_address(page);
	init_level2_page(level2p, addr);
	set_pud(level3p++, __pud(__pa(level2p) \| _KERNPG_TABLE));
	addr += PUD_SIZE;
	}
	/* clear the unused entries */
	while (addr < end_addr) {
	pud_clear(level3p++);
	addr += PUD_SIZE;
	}
	out:
	return result;
	}


	static int init_level4_page(struct kimage image, pgd_t level4p,
	unsigned long addr, unsigned long last_addr)
	{
	unsigned long end_addr;
	int result;

	result = 0;
	addr &= PAGE_MASK;
	end_addr = addr + (PTRS_PER_PGD * PGDIR_SIZE);
	while ((addr < last_addr) && (addr < end_addr)) {
	struct page *page;
	pud_t *level3p;

	page = kimage_alloc_control_pages(image, 0);
	if (!page) {
	result = -ENOMEM;
	goto out;
	}
	level3p = (pud_t *)page_address(page);
	result = init_level3_page(image, level3p, addr, last_addr);
	if (result)
	goto out;
	set_pgd(level4p++, __pgd(__pa(level3p) \| _KERNPG_TABLE));
	addr += PGDIR_SIZE;
	}
	/* clear the unused entries */
	while (addr < end_addr) {
	pgd_clear(level4p++);
	addr += PGDIR_SIZE;
	}
	out:
	return result;
	}

	static void free_transition_pgtable(struct kimage *image)
	{
	free_page((unsigned long)image->arch.pud);
	free_page((unsigned long)image->arch.pmd);
	free_page((unsigned long)image->arch.pte);
	}

	static int init_transition_pgtable(struct kimage image, pgd_t pgd)
	{
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte;
	unsigned long vaddr, paddr;
	int result = -ENOMEM;

	vaddr = (unsigned long)relocate_kernel;
	paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE);
	pgd += pgd_index(vaddr);
	if (!pgd_present(*pgd)) {
	pud = (pud_t *)get_zeroed_page(GFP_KERNEL);
	if (!pud)
	goto err;
	image->arch.pud = pud;
	set_pgd(pgd, __pgd(__pa(pud) \| _KERNPG_TABLE));
	}
	pud = pud_offset(pgd, vaddr);
	if (!pud_present(*pud)) {
	pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL);
	if (!pmd)
	goto err;
	image->arch.pmd = pmd;
	set_pud(pud, __pud(__pa(pmd) \| _KERNPG_TABLE));
	}
	pmd = pmd_offset(pud, vaddr);
	if (!pmd_present(*pmd)) {
	pte = (pte_t *)get_zeroed_page(GFP_KERNEL);
	if (!pte)
	goto err;
	image->arch.pte = pte;
	set_pmd(pmd, __pmd(__pa(pte) \| _KERNPG_TABLE));
	}
	pte = pte_offset_kernel(pmd, vaddr);
	set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
	return 0;
	err:
	free_transition_pgtable(image);
	return result;
	}


	static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
	{
	pgd_t *level4p;
	int result;
	level4p = (pgd_t *)__va(start_pgtable);
	result = init_level4_page(image, level4p, 0, max_pfn << PAGE_SHIFT);
	if (result)
	return result;
	/*
	* image->start may be outside 0 ~ max_pfn, for example when
	* jump back to original kernel from kexeced kernel
	*/
	result = init_one_level2_page(image, level4p, image->start);
	if (result)
	return result;
	return init_transition_pgtable(image, level4p);
	}

	static void set_idt(void *newidt, u16 limit)
	{
	struct desc_ptr curidt;

	/* x86-64 supports unaliged loads & stores */
	curidt.size = limit;
	curidt.address = (unsigned long)newidt;

	__asm__ __volatile__ (
	"lidtq %0\n"
	: : "m" (curidt)
	);
	};


	static void set_gdt(void *newgdt, u16 limit)
	{
	struct desc_ptr curgdt;

	/* x86-64 supports unaligned loads & stores */
	curgdt.size = limit;
	curgdt.address = (unsigned long)newgdt;

	__asm__ __volatile__ (
	"lgdtq %0\n"
	: : "m" (curgdt)
	);
	};

	static void load_segments(void)
	{
	__asm__ __volatile__ (
	"\tmovl %0,%%ds\n"
	"\tmovl %0,%%es\n"
	"\tmovl %0,%%ss\n"
	"\tmovl %0,%%fs\n"
	"\tmovl %0,%%gs\n"
	: : "a" (__KERNEL_DS) : "memory"
	);
	}

	int machine_kexec_prepare(struct kimage *image)
	{
	unsigned long start_pgtable;
	int result;

	/* Calculate the offsets */
	start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT;

	/* Setup the identity mapped 64bit page table */
	result = init_pgtable(image, start_pgtable);
	if (result)
	return result;

	return 0;
	}

	void machine_kexec_cleanup(struct kimage *image)
	{
	free_transition_pgtable(image);
	}

	/*
	* Do not allocate memory (or fail in any way) in machine_kexec().
	* We are past the point of no return, committed to rebooting now.
	*/
	void machine_kexec(struct kimage *image)
	{
	unsigned long page_list[PAGES_NR];
	void *control_page;
	int save_ftrace_enabled;

	#ifdef CONFIG_KEXEC_JUMP
	if (image->preserve_context)
	save_processor_state();
	#endif

	save_ftrace_enabled = __ftrace_enabled_save();

	/* Interrupts aren't acceptable while we reboot */
	local_irq_disable();
	hw_breakpoint_disable();

	if (image->preserve_context) {
	#ifdef CONFIG_X86_IO_APIC
	/*
	* We need to put APICs in legacy mode so that we can
	* get timer interrupts in second kernel. kexec/kdump
	* paths already have calls to disable_IO_APIC() in
	* one form or other. kexec jump path also need
	* one.
	*/
	disable_IO_APIC();
	#endif
	}

	control_page = page_address(image->control_code_page) + PAGE_SIZE;
	memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);

	page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page);
	page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
	page_list[PA_TABLE_PAGE] =
	(unsigned long)__pa(page_address(image->control_code_page));

	if (image->type == KEXEC_TYPE_DEFAULT)
	page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
	<< PAGE_SHIFT);

	/*
	* The segment registers are funny things, they have both a
	* visible and an invisible part. Whenever the visible part is
	* set to a specific selector, the invisible part is loaded
	* with from a table in memory. At no other time is the
	* descriptor table in memory accessed.
	*
	* I take advantage of this here by force loading the
	* segments, before I zap the gdt with an invalid value.
	*/
	load_segments();
	/*
	* The gdt & idt are now invalid.
	* If you want to load them you must set up your own idt & gdt.
	*/
	set_gdt(phys_to_virt(0), 0);
	set_idt(phys_to_virt(0), 0);

	/* now call it */
	image->start = relocate_kernel((unsigned long)image->head,
	(unsigned long)page_list,
	image->start,
	image->preserve_context);

	#ifdef CONFIG_KEXEC_JUMP
	if (image->preserve_context)
	restore_processor_state();
	#endif

	__ftrace_enabled_restore(save_ftrace_enabled);
	}

	void arch_crash_save_vmcoreinfo(void)
	{
	VMCOREINFO_SYMBOL(phys_base);
	VMCOREINFO_SYMBOL(init_level4_pgt);

	#ifdef CONFIG_NUMA
	VMCOREINFO_SYMBOL(node_data);
	VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
	#endif
	}