1 /* 2 * handle transition of Linux booting another kernel 3 * Copyright (C) 2002-2005 Eric Biederman <ebiederm@xmission.com> 4 * 5 * This source code is licensed under the GNU General Public License, 6 * Version 2. See the file COPYING for more details. 7 */ 8 9 #include <linux/mm.h> 10 #include <linux/kexec.h> 11 #include <linux/delay.h> 12 #include <linux/init.h> 13 #include <linux/numa.h> 14 #include <asm/pgtable.h> 15 #include <asm/pgalloc.h> 16 #include <asm/tlbflush.h> 17 #include <asm/mmu_context.h> 18 #include <asm/io.h> 19 #include <asm/apic.h> 20 #include <asm/cpufeature.h> 21 #include <asm/desc.h> 22 #include <asm/system.h> 23 24 #define PAGE_ALIGNED __attribute__ ((__aligned__(PAGE_SIZE))) 25 static u32 kexec_pgd[1024] PAGE_ALIGNED; 26 #ifdef CONFIG_X86_PAE 27 static u32 kexec_pmd0[1024] PAGE_ALIGNED; 28 static u32 kexec_pmd1[1024] PAGE_ALIGNED; 29 #endif 30 static u32 kexec_pte0[1024] PAGE_ALIGNED; 31 static u32 kexec_pte1[1024] PAGE_ALIGNED; 32 33 static void set_idt(void *newidt, __u16 limit) 34 { 35 struct Xgt_desc_struct curidt; 36 37 /* ia32 supports unaliged loads & stores */ 38 curidt.size = limit; 39 curidt.address = (unsigned long)newidt; 40 41 load_idt(&curidt); 42 }; 43 44 45 static void set_gdt(void *newgdt, __u16 limit) 46 { 47 struct Xgt_desc_struct curgdt; 48 49 /* ia32 supports unaligned loads & stores */ 50 curgdt.size = limit; 51 curgdt.address = (unsigned long)newgdt; 52 53 load_gdt(&curgdt); 54 }; 55 56 static void load_segments(void) 57 { 58 #define __STR(X) #X 59 #define STR(X) __STR(X) 60 61 __asm__ __volatile__ ( 62 "\tljmp $"STR(__KERNEL_CS)",$1f\n" 63 "\t1:\n" 64 "\tmovl $"STR(__KERNEL_DS)",%%eax\n" 65 "\tmovl %%eax,%%ds\n" 66 "\tmovl %%eax,%%es\n" 67 "\tmovl %%eax,%%fs\n" 68 "\tmovl %%eax,%%gs\n" 69 "\tmovl %%eax,%%ss\n" 70 ::: "eax", "memory"); 71 #undef STR 72 #undef __STR 73 } 74 75 /* 76 * A architecture hook called to validate the 77 * proposed image and prepare the control pages 78 * as needed. The pages for KEXEC_CONTROL_CODE_SIZE 79 * have been allocated, but the segments have yet 80 * been copied into the kernel. 81 * 82 * Do what every setup is needed on image and the 83 * reboot code buffer to allow us to avoid allocations 84 * later. 85 * 86 * Currently nothing. 87 */ 88 int machine_kexec_prepare(struct kimage *image) 89 { 90 return 0; 91 } 92 93 /* 94 * Undo anything leftover by machine_kexec_prepare 95 * when an image is freed. 96 */ 97 void machine_kexec_cleanup(struct kimage *image) 98 { 99 } 100 101 /* 102 * Do not allocate memory (or fail in any way) in machine_kexec(). 103 * We are past the point of no return, committed to rebooting now. 104 */ 105 NORET_TYPE void machine_kexec(struct kimage *image) 106 { 107 unsigned long page_list[PAGES_NR]; 108 void *control_page; 109 110 /* Interrupts aren't acceptable while we reboot */ 111 local_irq_disable(); 112 113 control_page = page_address(image->control_code_page); 114 memcpy(control_page, relocate_kernel, PAGE_SIZE); 115 116 page_list[PA_CONTROL_PAGE] = __pa(control_page); 117 page_list[VA_CONTROL_PAGE] = (unsigned long)relocate_kernel; 118 page_list[PA_PGD] = __pa(kexec_pgd); 119 page_list[VA_PGD] = (unsigned long)kexec_pgd; 120 #ifdef CONFIG_X86_PAE 121 page_list[PA_PMD_0] = __pa(kexec_pmd0); 122 page_list[VA_PMD_0] = (unsigned long)kexec_pmd0; 123 page_list[PA_PMD_1] = __pa(kexec_pmd1); 124 page_list[VA_PMD_1] = (unsigned long)kexec_pmd1; 125 #endif 126 page_list[PA_PTE_0] = __pa(kexec_pte0); 127 page_list[VA_PTE_0] = (unsigned long)kexec_pte0; 128 page_list[PA_PTE_1] = __pa(kexec_pte1); 129 page_list[VA_PTE_1] = (unsigned long)kexec_pte1; 130 131 /* The segment registers are funny things, they have both a 132 * visible and an invisible part. Whenever the visible part is 133 * set to a specific selector, the invisible part is loaded 134 * with from a table in memory. At no other time is the 135 * descriptor table in memory accessed. 136 * 137 * I take advantage of this here by force loading the 138 * segments, before I zap the gdt with an invalid value. 139 */ 140 load_segments(); 141 /* The gdt & idt are now invalid. 142 * If you want to load them you must set up your own idt & gdt. 143 */ 144 set_gdt(phys_to_virt(0),0); 145 set_idt(phys_to_virt(0),0); 146 147 /* now call it */ 148 relocate_kernel((unsigned long)image->head, (unsigned long)page_list, 149 image->start, cpu_has_pae); 150 } 151 152 void arch_crash_save_vmcoreinfo(void) 153 { 154 #ifdef CONFIG_ARCH_DISCONTIGMEM_ENABLE 155 VMCOREINFO_SYMBOL(node_data); 156 VMCOREINFO_LENGTH(node_data, MAX_NUMNODES); 157 #endif 158 #ifdef CONFIG_X86_PAE 159 VMCOREINFO_CONFIG(X86_PAE); 160 #endif 161 } 162 163