/* * 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 <linux/numa.h> #include <linux/ftrace.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, max_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. */ void machine_kexec(struct kimage *image) { unsigned long page_list[PAGES_NR]; void *control_page; tracer_disable(); /* 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); } 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 }