arch/x86_64/kernel/machine_kexec.c - maze/linux - Git at Google

 /*
  * machine_kexec.c - 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/reboot.h>
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
 #include <asm/mmu_context.h>
 #include <asm/io.h>

 #define PAGE_ALIGNED __attribute__ ((__aligned__(PAGE_SIZE)))
 static u64 kexec_pgd[512] PAGE_ALIGNED;
 static u64 kexec_pud0[512] PAGE_ALIGNED;
 static u64 kexec_pmd0[512] PAGE_ALIGNED;
 static u64 kexec_pte0[512] PAGE_ALIGNED;
 static u64 kexec_pud1[512] PAGE_ALIGNED;
 static u64 kexec_pmd1[512] PAGE_ALIGNED;
 static u64 kexec_pte1[512] PAGE_ALIGNED;

 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 int init_pgtable(struct kimage *image, unsigned long start_pgtable)
 {
 	pgd_t *level4p;
 	level4p = (pgd_t *)__va(start_pgtable);
  	return init_level4_page(image, level4p, 0, end_pfn << PAGE_SHIFT);
 }

 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)
 {
 	return;
 }

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

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

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

 	page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page);
 	page_list[VA_CONTROL_PAGE] = (unsigned long)relocate_kernel;
 	page_list[PA_PGD] = virt_to_phys(&kexec_pgd);
 	page_list[VA_PGD] = (unsigned long)kexec_pgd;
 	page_list[PA_PUD_0] = virt_to_phys(&kexec_pud0);
 	page_list[VA_PUD_0] = (unsigned long)kexec_pud0;
 	page_list[PA_PMD_0] = virt_to_phys(&kexec_pmd0);
 	page_list[VA_PMD_0] = (unsigned long)kexec_pmd0;
 	page_list[PA_PTE_0] = virt_to_phys(&kexec_pte0);
 	page_list[VA_PTE_0] = (unsigned long)kexec_pte0;
 	page_list[PA_PUD_1] = virt_to_phys(&kexec_pud1);
 	page_list[VA_PUD_1] = (unsigned long)kexec_pud1;
 	page_list[PA_PMD_1] = virt_to_phys(&kexec_pmd1);
 	page_list[VA_PMD_1] = (unsigned long)kexec_pmd1;
 	page_list[PA_PTE_1] = virt_to_phys(&kexec_pte1);
 	page_list[VA_PTE_1] = (unsigned long)kexec_pte1;

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

 	/* 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 */
 	relocate_kernel((unsigned long)image->head, (unsigned long)page_list,
 			image->start);
 }

 /* crashkernel=size@addr specifies the location to reserve for
  * a crash kernel.  By reserving this memory we guarantee
  * that linux never set's it up as a DMA target.
  * Useful for holding code to do something appropriate
  * after a kernel panic.
  */
 static int __init setup_crashkernel(char *arg)
 {
 	unsigned long size, base;
 	char *p;
 	if (!arg)
 		return -EINVAL;
 	size = memparse(arg, &p);
 	if (arg == p)
 		return -EINVAL;
 	if (*p == '@') {
 		base = memparse(p+1, &p);
 		/* FIXME: Do I want a sanity check to validate the
 		 * memory range?  Yes you do, but it's too early for
 		 * e820 -AK */
 		crashk_res.start = base;
 		crashk_res.end   = base + size - 1;
 	}
 	return 0;
 }
 early_param("crashkernel", setup_crashkernel);
	/*
	* machine_kexec.c - 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/reboot.h>
	#include <asm/pgtable.h>
	#include <asm/tlbflush.h>
	#include <asm/mmu_context.h>
	#include <asm/io.h>

	#define PAGE_ALIGNED __attribute__ ((__aligned__(PAGE_SIZE)))
	static u64 kexec_pgd[512] PAGE_ALIGNED;
	static u64 kexec_pud0[512] PAGE_ALIGNED;
	static u64 kexec_pmd0[512] PAGE_ALIGNED;
	static u64 kexec_pte0[512] PAGE_ALIGNED;
	static u64 kexec_pud1[512] PAGE_ALIGNED;
	static u64 kexec_pmd1[512] PAGE_ALIGNED;
	static u64 kexec_pte1[512] PAGE_ALIGNED;

	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 int init_pgtable(struct kimage *image, unsigned long start_pgtable)
	{
	pgd_t *level4p;
	level4p = (pgd_t *)__va(start_pgtable);
	return init_level4_page(image, level4p, 0, end_pfn << PAGE_SHIFT);
	}

	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)
	{
	return;
	}

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

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

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

	page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page);
	page_list[VA_CONTROL_PAGE] = (unsigned long)relocate_kernel;
	page_list[PA_PGD] = virt_to_phys(&kexec_pgd);
	page_list[VA_PGD] = (unsigned long)kexec_pgd;
	page_list[PA_PUD_0] = virt_to_phys(&kexec_pud0);
	page_list[VA_PUD_0] = (unsigned long)kexec_pud0;
	page_list[PA_PMD_0] = virt_to_phys(&kexec_pmd0);
	page_list[VA_PMD_0] = (unsigned long)kexec_pmd0;
	page_list[PA_PTE_0] = virt_to_phys(&kexec_pte0);
	page_list[VA_PTE_0] = (unsigned long)kexec_pte0;
	page_list[PA_PUD_1] = virt_to_phys(&kexec_pud1);
	page_list[VA_PUD_1] = (unsigned long)kexec_pud1;
	page_list[PA_PMD_1] = virt_to_phys(&kexec_pmd1);
	page_list[VA_PMD_1] = (unsigned long)kexec_pmd1;
	page_list[PA_PTE_1] = virt_to_phys(&kexec_pte1);
	page_list[VA_PTE_1] = (unsigned long)kexec_pte1;

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

	/* 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 */
	relocate_kernel((unsigned long)image->head, (unsigned long)page_list,
	image->start);
	}

	/* crashkernel=size@addr specifies the location to reserve for
	* a crash kernel. By reserving this memory we guarantee
	* that linux never set's it up as a DMA target.
	* Useful for holding code to do something appropriate
	* after a kernel panic.
	*/
	static int __init setup_crashkernel(char *arg)
	{
	unsigned long size, base;
	char *p;
	if (!arg)
	return -EINVAL;
	size = memparse(arg, &p);
	if (arg == p)
	return -EINVAL;
	if (*p == '@') {
	base = memparse(p+1, &p);
	/* FIXME: Do I want a sanity check to validate the
	* memory range? Yes you do, but it's too early for
	* e820 -AK */
	crashk_res.start = base;
	crashk_res.end = base + size - 1;
	}
	return 0;
	}
	early_param("crashkernel", setup_crashkernel);