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 <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 desc_ptr 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 desc_ptr 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_NUMA
 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