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 <linux/ftrace.h> 15 16 #include <asm/pgtable.h> 17 #include <asm/pgalloc.h> 18 #include <asm/tlbflush.h> 19 #include <asm/mmu_context.h> 20 #include <asm/io.h> 21 #include <asm/apic.h> 22 #include <asm/cpufeature.h> 23 #include <asm/desc.h> 24 #include <asm/system.h> 25 26 #define PAGE_ALIGNED __attribute__ ((__aligned__(PAGE_SIZE))) 27 static u32 kexec_pgd[1024] PAGE_ALIGNED; 28 #ifdef CONFIG_X86_PAE 29 static u32 kexec_pmd0[1024] PAGE_ALIGNED; 30 static u32 kexec_pmd1[1024] PAGE_ALIGNED; 31 #endif 32 static u32 kexec_pte0[1024] PAGE_ALIGNED; 33 static u32 kexec_pte1[1024] PAGE_ALIGNED; 34 35 static void set_idt(void *newidt, __u16 limit) 36 { 37 struct desc_ptr curidt; 38 39 /* ia32 supports unaliged loads & stores */ 40 curidt.size = limit; 41 curidt.address = (unsigned long)newidt; 42 43 load_idt(&curidt); 44 } 45 46 47 static void set_gdt(void *newgdt, __u16 limit) 48 { 49 struct desc_ptr curgdt; 50 51 /* ia32 supports unaligned loads & stores */ 52 curgdt.size = limit; 53 curgdt.address = (unsigned long)newgdt; 54 55 load_gdt(&curgdt); 56 } 57 58 static void load_segments(void) 59 { 60 #define __STR(X) #X 61 #define STR(X) __STR(X) 62 63 __asm__ __volatile__ ( 64 "\tljmp $"STR(__KERNEL_CS)",$1f\n" 65 "\t1:\n" 66 "\tmovl $"STR(__KERNEL_DS)",%%eax\n" 67 "\tmovl %%eax,%%ds\n" 68 "\tmovl %%eax,%%es\n" 69 "\tmovl %%eax,%%fs\n" 70 "\tmovl %%eax,%%gs\n" 71 "\tmovl %%eax,%%ss\n" 72 ::: "eax", "memory"); 73 #undef STR 74 #undef __STR 75 } 76 77 /* 78 * A architecture hook called to validate the 79 * proposed image and prepare the control pages 80 * as needed. The pages for KEXEC_CONTROL_CODE_SIZE 81 * have been allocated, but the segments have yet 82 * been copied into the kernel. 83 * 84 * Do what every setup is needed on image and the 85 * reboot code buffer to allow us to avoid allocations 86 * later. 87 * 88 * Currently nothing. 89 */ 90 int machine_kexec_prepare(struct kimage *image) 91 { 92 return 0; 93 } 94 95 /* 96 * Undo anything leftover by machine_kexec_prepare 97 * when an image is freed. 98 */ 99 void machine_kexec_cleanup(struct kimage *image) 100 { 101 } 102 103 /* 104 * Do not allocate memory (or fail in any way) in machine_kexec(). 105 * We are past the point of no return, committed to rebooting now. 106 */ 107 NORET_TYPE void machine_kexec(struct kimage *image) 108 { 109 unsigned long page_list[PAGES_NR]; 110 void *control_page; 111 112 tracer_disable(); 113 114 /* Interrupts aren't acceptable while we reboot */ 115 local_irq_disable(); 116 117 control_page = page_address(image->control_code_page); 118 memcpy(control_page, relocate_kernel, PAGE_SIZE); 119 120 page_list[PA_CONTROL_PAGE] = __pa(control_page); 121 page_list[VA_CONTROL_PAGE] = (unsigned long)relocate_kernel; 122 page_list[PA_PGD] = __pa(kexec_pgd); 123 page_list[VA_PGD] = (unsigned long)kexec_pgd; 124 #ifdef CONFIG_X86_PAE 125 page_list[PA_PMD_0] = __pa(kexec_pmd0); 126 page_list[VA_PMD_0] = (unsigned long)kexec_pmd0; 127 page_list[PA_PMD_1] = __pa(kexec_pmd1); 128 page_list[VA_PMD_1] = (unsigned long)kexec_pmd1; 129 #endif 130 page_list[PA_PTE_0] = __pa(kexec_pte0); 131 page_list[VA_PTE_0] = (unsigned long)kexec_pte0; 132 page_list[PA_PTE_1] = __pa(kexec_pte1); 133 page_list[VA_PTE_1] = (unsigned long)kexec_pte1; 134 135 /* The segment registers are funny things, they have both a 136 * visible and an invisible part. Whenever the visible part is 137 * set to a specific selector, the invisible part is loaded 138 * with from a table in memory. At no other time is the 139 * descriptor table in memory accessed. 140 * 141 * I take advantage of this here by force loading the 142 * segments, before I zap the gdt with an invalid value. 143 */ 144 load_segments(); 145 /* The gdt & idt are now invalid. 146 * If you want to load them you must set up your own idt & gdt. 147 */ 148 set_gdt(phys_to_virt(0),0); 149 set_idt(phys_to_virt(0),0); 150 151 /* now call it */ 152 relocate_kernel((unsigned long)image->head, (unsigned long)page_list, 153 image->start, cpu_has_pae); 154 } 155 156 void arch_crash_save_vmcoreinfo(void) 157 { 158 #ifdef CONFIG_NUMA 159 VMCOREINFO_SYMBOL(node_data); 160 VMCOREINFO_LENGTH(node_data, MAX_NUMNODES); 161 #endif 162 #ifdef CONFIG_X86_PAE 163 VMCOREINFO_CONFIG(X86_PAE); 164 #endif 165 } 166 167