arch/x86/kernel/machine_kexec_32.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/delay.h>
 #include <linux/numa.h>
 #include <linux/ftrace.h>
 #include <linux/suspend.h>
 #include <linux/gfp.h>
 #include <linux/io.h>

 #include <asm/pgtable.h>
 #include <asm/pgalloc.h>
 #include <asm/tlbflush.h>
 #include <asm/mmu_context.h>
 #include <asm/apic.h>
 #include <asm/io_apic.h>
 #include <asm/cpufeature.h>
 #include <asm/desc.h>
 #include <asm/set_memory.h>
 #include <asm/debugreg.h>

 static void set_gdt(void *newgdt, __u16 limit)
 {
 	struct desc_ptr curgdt;

 	/* ia32 supports unaligned loads & stores */
 	curgdt.size    = limit;
 	curgdt.address = (unsigned long)newgdt;

 	load_gdt(&curgdt);
 }

 static void load_segments(void)
 {
 #define __STR(X) #X
 #define STR(X) __STR(X)

 	__asm__ __volatile__ (
 		"\tljmp $"STR(__KERNEL_CS)",$1f\n"
 		"\t1:\n"
 		"\tmovl $"STR(__KERNEL_DS)",%%eax\n"
 		"\tmovl %%eax,%%ds\n"
 		"\tmovl %%eax,%%es\n"
 		"\tmovl %%eax,%%ss\n"
 		: : : "eax", "memory");
 #undef STR
 #undef __STR
 }

 static void machine_kexec_free_page_tables(struct kimage *image)
 {
 	free_page((unsigned long)image->arch.pgd);
 	image->arch.pgd = NULL;
 #ifdef CONFIG_X86_PAE
 	free_page((unsigned long)image->arch.pmd0);
 	image->arch.pmd0 = NULL;
 	free_page((unsigned long)image->arch.pmd1);
 	image->arch.pmd1 = NULL;
 #endif
 	free_page((unsigned long)image->arch.pte0);
 	image->arch.pte0 = NULL;
 	free_page((unsigned long)image->arch.pte1);
 	image->arch.pte1 = NULL;
 }

 static int machine_kexec_alloc_page_tables(struct kimage *image)
 {
 	image->arch.pgd = (pgd_t *)get_zeroed_page(GFP_KERNEL);
 #ifdef CONFIG_X86_PAE
 	image->arch.pmd0 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
 	image->arch.pmd1 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
 #endif
 	image->arch.pte0 = (pte_t *)get_zeroed_page(GFP_KERNEL);
 	image->arch.pte1 = (pte_t *)get_zeroed_page(GFP_KERNEL);
 	if (!image->arch.pgd ||
 #ifdef CONFIG_X86_PAE
 	    !image->arch.pmd0 || !image->arch.pmd1 ||
 #endif
 	    !image->arch.pte0 || !image->arch.pte1) {
 		return -ENOMEM;
 	}
 	return 0;
 }

 static void machine_kexec_page_table_set_one(
 	pgd_t *pgd, pmd_t *pmd, pte_t *pte,
 	unsigned long vaddr, unsigned long paddr)
 {
 	p4d_t *p4d;
 	pud_t *pud;

 	pgd += pgd_index(vaddr);
 #ifdef CONFIG_X86_PAE
 	if (!(pgd_val(*pgd) & _PAGE_PRESENT))
 		set_pgd(pgd, __pgd(__pa(pmd) | _PAGE_PRESENT));
 #endif
 	p4d = p4d_offset(pgd, vaddr);
 	pud = pud_offset(p4d, vaddr);
 	pmd = pmd_offset(pud, vaddr);
 	if (!(pmd_val(*pmd) & _PAGE_PRESENT))
 		set_pmd(pmd, __pmd(__pa(pte) | _PAGE_TABLE));
 	pte = pte_offset_kernel(pmd, vaddr);
 	set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
 }

 static void machine_kexec_prepare_page_tables(struct kimage *image)
 {
 	void *control_page;
 	pmd_t *pmd = NULL;

 	control_page = page_address(image->control_code_page);
 #ifdef CONFIG_X86_PAE
 	pmd = image->arch.pmd0;
 #endif
 	machine_kexec_page_table_set_one(
 		image->arch.pgd, pmd, image->arch.pte0,
 		(unsigned long)control_page, __pa(control_page));
 #ifdef CONFIG_X86_PAE
 	pmd = image->arch.pmd1;
 #endif
 	machine_kexec_page_table_set_one(
 		image->arch.pgd, pmd, image->arch.pte1,
 		__pa(control_page), __pa(control_page));
 }

 /*
  * A architecture hook called to validate the
  * proposed image and prepare the control pages
  * as needed.  The pages for KEXEC_CONTROL_PAGE_SIZE
  * have been allocated, but the segments have yet
  * been copied into the kernel.
  *
  * Do what every setup is needed on image and the
  * reboot code buffer to allow us to avoid allocations
  * later.
  *
  * - Make control page executable.
  * - Allocate page tables
  * - Setup page tables
  */
 int machine_kexec_prepare(struct kimage *image)
 {
 	int error;

 	set_pages_x(image->control_code_page, 1);
 	error = machine_kexec_alloc_page_tables(image);
 	if (error)
 		return error;
 	machine_kexec_prepare_page_tables(image);
 	return 0;
 }

 /*
  * Undo anything leftover by machine_kexec_prepare
  * when an image is freed.
  */
 void machine_kexec_cleanup(struct kimage *image)
 {
 	set_pages_nx(image->control_code_page, 1);
 	machine_kexec_free_page_tables(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;
 	asmlinkage unsigned long
 		(*relocate_kernel_ptr)(unsigned long indirection_page,
 				       unsigned long control_page,
 				       unsigned long start_address,
 				       unsigned int has_pae,
 				       unsigned int preserve_context);

 #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 restore_boot_irq_mode()
 		 * in one form or other. kexec jump path also need one.
 		 */
 		clear_IO_APIC();
 		restore_boot_irq_mode();
 #endif
 	}

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

 	relocate_kernel_ptr = control_page;
 	page_list[PA_CONTROL_PAGE] = __pa(control_page);
 	page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
 	page_list[PA_PGD] = __pa(image->arch.pgd);

 	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.
 	 */
 	idt_invalidate(phys_to_virt(0));
 	set_gdt(phys_to_virt(0), 0);

 	/* now call it */
 	image->start = relocate_kernel_ptr((unsigned long)image->head,
 					   (unsigned long)page_list,
 					   image->start,
 					   boot_cpu_has(X86_FEATURE_PAE),
 					   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)
 {
 #ifdef CONFIG_NUMA
 	VMCOREINFO_SYMBOL(node_data);
 	VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
 #endif
 #ifdef CONFIG_X86_PAE
 	VMCOREINFO_CONFIG(X86_PAE);
 #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/delay.h>
	#include <linux/numa.h>
	#include <linux/ftrace.h>
	#include <linux/suspend.h>
	#include <linux/gfp.h>
	#include <linux/io.h>

	#include <asm/pgtable.h>
	#include <asm/pgalloc.h>
	#include <asm/tlbflush.h>
	#include <asm/mmu_context.h>
	#include <asm/apic.h>
	#include <asm/io_apic.h>
	#include <asm/cpufeature.h>
	#include <asm/desc.h>
	#include <asm/set_memory.h>
	#include <asm/debugreg.h>

	static void set_gdt(void *newgdt, __u16 limit)
	{
	struct desc_ptr curgdt;

	/* ia32 supports unaligned loads & stores */
	curgdt.size = limit;
	curgdt.address = (unsigned long)newgdt;

	load_gdt(&curgdt);
	}

	static void load_segments(void)
	{
	#define __STR(X) #X
	#define STR(X) __STR(X)

	__asm__ __volatile__ (
	"\tljmp $"STR(__KERNEL_CS)",$1f\n"
	"\t1:\n"
	"\tmovl $"STR(__KERNEL_DS)",%%eax\n"
	"\tmovl %%eax,%%ds\n"
	"\tmovl %%eax,%%es\n"
	"\tmovl %%eax,%%ss\n"
	: : : "eax", "memory");
	#undef STR
	#undef __STR
	}

	static void machine_kexec_free_page_tables(struct kimage *image)
	{
	free_page((unsigned long)image->arch.pgd);
	image->arch.pgd = NULL;
	#ifdef CONFIG_X86_PAE
	free_page((unsigned long)image->arch.pmd0);
	image->arch.pmd0 = NULL;
	free_page((unsigned long)image->arch.pmd1);
	image->arch.pmd1 = NULL;
	#endif
	free_page((unsigned long)image->arch.pte0);
	image->arch.pte0 = NULL;
	free_page((unsigned long)image->arch.pte1);
	image->arch.pte1 = NULL;
	}

	static int machine_kexec_alloc_page_tables(struct kimage *image)
	{
	image->arch.pgd = (pgd_t *)get_zeroed_page(GFP_KERNEL);
	#ifdef CONFIG_X86_PAE
	image->arch.pmd0 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
	image->arch.pmd1 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
	#endif
	image->arch.pte0 = (pte_t *)get_zeroed_page(GFP_KERNEL);
	image->arch.pte1 = (pte_t *)get_zeroed_page(GFP_KERNEL);
	if (!image->arch.pgd \|\|
	#ifdef CONFIG_X86_PAE
	!image->arch.pmd0 \|\| !image->arch.pmd1 \|\|
	#endif
	!image->arch.pte0 \|\| !image->arch.pte1) {
	return -ENOMEM;
	}
	return 0;
	}

	static void machine_kexec_page_table_set_one(
	pgd_t pgd, pmd_t pmd, pte_t *pte,
	unsigned long vaddr, unsigned long paddr)
	{
	p4d_t *p4d;
	pud_t *pud;

	pgd += pgd_index(vaddr);
	#ifdef CONFIG_X86_PAE
	if (!(pgd_val(*pgd) & _PAGE_PRESENT))
	set_pgd(pgd, __pgd(__pa(pmd) \| _PAGE_PRESENT));
	#endif
	p4d = p4d_offset(pgd, vaddr);
	pud = pud_offset(p4d, vaddr);
	pmd = pmd_offset(pud, vaddr);
	if (!(pmd_val(*pmd) & _PAGE_PRESENT))
	set_pmd(pmd, __pmd(__pa(pte) \| _PAGE_TABLE));
	pte = pte_offset_kernel(pmd, vaddr);
	set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
	}

	static void machine_kexec_prepare_page_tables(struct kimage *image)
	{
	void *control_page;
	pmd_t *pmd = NULL;

	control_page = page_address(image->control_code_page);
	#ifdef CONFIG_X86_PAE
	pmd = image->arch.pmd0;
	#endif
	machine_kexec_page_table_set_one(
	image->arch.pgd, pmd, image->arch.pte0,
	(unsigned long)control_page, __pa(control_page));
	#ifdef CONFIG_X86_PAE
	pmd = image->arch.pmd1;
	#endif
	machine_kexec_page_table_set_one(
	image->arch.pgd, pmd, image->arch.pte1,
	__pa(control_page), __pa(control_page));
	}

	/*
	* A architecture hook called to validate the
	* proposed image and prepare the control pages
	* as needed. The pages for KEXEC_CONTROL_PAGE_SIZE
	* have been allocated, but the segments have yet
	* been copied into the kernel.
	*
	* Do what every setup is needed on image and the
	* reboot code buffer to allow us to avoid allocations
	* later.
	*
	* - Make control page executable.
	* - Allocate page tables
	* - Setup page tables
	*/
	int machine_kexec_prepare(struct kimage *image)
	{
	int error;

	set_pages_x(image->control_code_page, 1);
	error = machine_kexec_alloc_page_tables(image);
	if (error)
	return error;
	machine_kexec_prepare_page_tables(image);
	return 0;
	}

	/*
	* Undo anything leftover by machine_kexec_prepare
	* when an image is freed.
	*/
	void machine_kexec_cleanup(struct kimage *image)
	{
	set_pages_nx(image->control_code_page, 1);
	machine_kexec_free_page_tables(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;
	asmlinkage unsigned long
	(*relocate_kernel_ptr)(unsigned long indirection_page,
	unsigned long control_page,
	unsigned long start_address,
	unsigned int has_pae,
	unsigned int preserve_context);

	#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 restore_boot_irq_mode()
	* in one form or other. kexec jump path also need one.
	*/
	clear_IO_APIC();
	restore_boot_irq_mode();
	#endif
	}

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

	relocate_kernel_ptr = control_page;
	page_list[PA_CONTROL_PAGE] = __pa(control_page);
	page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
	page_list[PA_PGD] = __pa(image->arch.pgd);

	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.
	*/
	idt_invalidate(phys_to_virt(0));
	set_gdt(phys_to_virt(0), 0);

	/* now call it */
	image->start = relocate_kernel_ptr((unsigned long)image->head,
	(unsigned long)page_list,
	image->start,
	boot_cpu_has(X86_FEATURE_PAE),
	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)
	{
	#ifdef CONFIG_NUMA
	VMCOREINFO_SYMBOL(node_data);
	VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
	#endif
	#ifdef CONFIG_X86_PAE
	VMCOREINFO_CONFIG(X86_PAE);
	#endif
	}