arch/x86/kernel/machine_kexec_32.c

   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