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 #include <linux/suspend.h>
  16 #include <linux/gfp.h>
  17 #include <linux/io.h>
  18
  19 #include <asm/pgtable.h>
  20 #include <asm/pgalloc.h>
  21 #include <asm/tlbflush.h>
  22 #include <asm/mmu_context.h>
  23 #include <asm/apic.h>
  24 #include <asm/cpufeature.h>
  25 #include <asm/desc.h>
  26 #include <asm/system.h>
  27 #include <asm/cacheflush.h>
  28 #include <asm/debugreg.h>
  29
  30 static void set_idt(void *newidt, __u16 limit)
  31 {
  32         struct desc_ptr curidt;
  33
  34         /* ia32 supports unaliged loads & stores */
  35         curidt.size    = limit;
  36         curidt.address = (unsigned long)newidt;
  37
  38         load_idt(&curidt);
  39 }
  40
  41
  42 static void set_gdt(void *newgdt, __u16 limit)
  43 {
  44         struct desc_ptr curgdt;
  45
  46         /* ia32 supports unaligned loads & stores */
  47         curgdt.size    = limit;
  48         curgdt.address = (unsigned long)newgdt;
  49
  50         load_gdt(&curgdt);
  51 }
  52
  53 static void load_segments(void)
  54 {
  55 #define __STR(X) #X
  56 #define STR(X) __STR(X)
  57
  58         __asm__ __volatile__ (
  59                 "\tljmp $"STR(__KERNEL_CS)",$1f\n"
  60                 "\t1:\n"
  61                 "\tmovl $"STR(__KERNEL_DS)",%%eax\n"
  62                 "\tmovl %%eax,%%ds\n"
  63                 "\tmovl %%eax,%%es\n"
  64                 "\tmovl %%eax,%%fs\n"
  65                 "\tmovl %%eax,%%gs\n"
  66                 "\tmovl %%eax,%%ss\n"
  67                 : : : "eax", "memory");
  68 #undef STR
  69 #undef __STR
  70 }
  71
  72 static void machine_kexec_free_page_tables(struct kimage *image)
  73 {
  74         free_page((unsigned long)image->arch.pgd);
  75 #ifdef CONFIG_X86_PAE
  76         free_page((unsigned long)image->arch.pmd0);
  77         free_page((unsigned long)image->arch.pmd1);
  78 #endif
  79         free_page((unsigned long)image->arch.pte0);
  80         free_page((unsigned long)image->arch.pte1);
  81 }
  82
  83 static int machine_kexec_alloc_page_tables(struct kimage *image)
  84 {
  85         image->arch.pgd = (pgd_t *)get_zeroed_page(GFP_KERNEL);
  86 #ifdef CONFIG_X86_PAE
  87         image->arch.pmd0 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
  88         image->arch.pmd1 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
  89 #endif
  90         image->arch.pte0 = (pte_t *)get_zeroed_page(GFP_KERNEL);
  91         image->arch.pte1 = (pte_t *)get_zeroed_page(GFP_KERNEL);
  92         if (!image->arch.pgd ||
  93 #ifdef CONFIG_X86_PAE
  94             !image->arch.pmd0 || !image->arch.pmd1 ||
  95 #endif
  96             !image->arch.pte0 || !image->arch.pte1) {
  97                 machine_kexec_free_page_tables(image);
  98                 return -ENOMEM;
  99         }
 100         return 0;
 101 }
 102
 103 static void machine_kexec_page_table_set_one(
 104         pgd_t *pgd, pmd_t *pmd, pte_t *pte,
 105         unsigned long vaddr, unsigned long paddr)
 106 {
 107         pud_t *pud;
 108
 109         pgd += pgd_index(vaddr);
 110 #ifdef CONFIG_X86_PAE
 111         if (!(pgd_val(*pgd) & _PAGE_PRESENT))
 112                 set_pgd(pgd, __pgd(__pa(pmd) | _PAGE_PRESENT));
 113 #endif
 114         pud = pud_offset(pgd, vaddr);
 115         pmd = pmd_offset(pud, vaddr);
 116         if (!(pmd_val(*pmd) & _PAGE_PRESENT))
 117                 set_pmd(pmd, __pmd(__pa(pte) | _PAGE_TABLE));
 118         pte = pte_offset_kernel(pmd, vaddr);
 119         set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
 120 }
 121
 122 static void machine_kexec_prepare_page_tables(struct kimage *image)
 123 {
 124         void *control_page;
 125         pmd_t *pmd = NULL;
 126
 127         control_page = page_address(image->control_code_page);
 128 #ifdef CONFIG_X86_PAE
 129         pmd = image->arch.pmd0;
 130 #endif
 131         machine_kexec_page_table_set_one(
 132                 image->arch.pgd, pmd, image->arch.pte0,
 133                 (unsigned long)control_page, __pa(control_page));
 134 #ifdef CONFIG_X86_PAE
 135         pmd = image->arch.pmd1;
 136 #endif
 137         machine_kexec_page_table_set_one(
 138                 image->arch.pgd, pmd, image->arch.pte1,
 139                 __pa(control_page), __pa(control_page));
 140 }
 141
 142 /*
 143  * A architecture hook called to validate the
 144  * proposed image and prepare the control pages
 145  * as needed.  The pages for KEXEC_CONTROL_PAGE_SIZE
 146  * have been allocated, but the segments have yet
 147  * been copied into the kernel.
 148  *
 149  * Do what every setup is needed on image and the
 150  * reboot code buffer to allow us to avoid allocations
 151  * later.
 152  *
 153  * - Make control page executable.
 154  * - Allocate page tables
 155  * - Setup page tables
 156  */
 157 int machine_kexec_prepare(struct kimage *image)
 158 {
 159         int error;
 160
 161         set_pages_x(image->control_code_page, 1);
 162         error = machine_kexec_alloc_page_tables(image);
 163         if (error)
 164                 return error;
 165         machine_kexec_prepare_page_tables(image);
 166         return 0;
 167 }
 168
 169 /*
 170  * Undo anything leftover by machine_kexec_prepare
 171  * when an image is freed.
 172  */
 173 void machine_kexec_cleanup(struct kimage *image)
 174 {
 175         set_pages_nx(image->control_code_page, 1);
 176         machine_kexec_free_page_tables(image);
 177 }
 178
 179 /*
 180  * Do not allocate memory (or fail in any way) in machine_kexec().
 181  * We are past the point of no return, committed to rebooting now.
 182  */
 183 void machine_kexec(struct kimage *image)
 184 {
 185         unsigned long page_list[PAGES_NR];
 186         void *control_page;
 187         int save_ftrace_enabled;
 188         asmlinkage unsigned long
 189                 (*relocate_kernel_ptr)(unsigned long indirection_page,
 190                                        unsigned long control_page,
 191                                        unsigned long start_address,
 192                                        unsigned int has_pae,
 193                                        unsigned int preserve_context);
 194
 195 #ifdef CONFIG_KEXEC_JUMP
 196         if (image->preserve_context)
 197                 save_processor_state();
 198 #endif
 199
 200         save_ftrace_enabled = __ftrace_enabled_save();
 201
 202         /* Interrupts aren't acceptable while we reboot */
 203         local_irq_disable();
 204         hw_breakpoint_disable();
 205
 206         if (image->preserve_context) {
 207 #ifdef CONFIG_X86_IO_APIC
 208                 /*
 209                  * We need to put APICs in legacy mode so that we can
 210                  * get timer interrupts in second kernel. kexec/kdump
 211                  * paths already have calls to disable_IO_APIC() in
 212                  * one form or other. kexec jump path also need
 213                  * one.
 214                  */
 215                 disable_IO_APIC();
 216 #endif
 217         }
 218
 219         control_page = page_address(image->control_code_page);
 220         memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
 221
 222         relocate_kernel_ptr = control_page;
 223         page_list[PA_CONTROL_PAGE] = __pa(control_page);
 224         page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
 225         page_list[PA_PGD] = __pa(image->arch.pgd);
 226
 227         if (image->type == KEXEC_TYPE_DEFAULT)
 228                 page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
 229                                                 << PAGE_SHIFT);
 230
 231         /*
 232          * The segment registers are funny things, they have both a
 233          * visible and an invisible part.  Whenever the visible part is
 234          * set to a specific selector, the invisible part is loaded
 235          * with from a table in memory.  At no other time is the
 236          * descriptor table in memory accessed.
 237          *
 238          * I take advantage of this here by force loading the
 239          * segments, before I zap the gdt with an invalid value.
 240          */
 241         load_segments();
 242         /*
 243          * The gdt & idt are now invalid.
 244          * If you want to load them you must set up your own idt & gdt.
 245          */
 246         set_gdt(phys_to_virt(0), 0);
 247         set_idt(phys_to_virt(0), 0);
 248
 249         /* now call it */
 250         image->start = relocate_kernel_ptr((unsigned long)image->head,
 251                                            (unsigned long)page_list,
 252                                            image->start, cpu_has_pae,
 253                                            image->preserve_context);
 254
 255 #ifdef CONFIG_KEXEC_JUMP
 256         if (image->preserve_context)
 257                 restore_processor_state();
 258 #endif
 259
 260         __ftrace_enabled_restore(save_ftrace_enabled);
 261 }
 262
 263 void arch_crash_save_vmcoreinfo(void)
 264 {
 265 #ifdef CONFIG_NUMA
 266         VMCOREINFO_SYMBOL(node_data);
 267         VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
 268 #endif
 269 #ifdef CONFIG_X86_PAE
 270         VMCOREINFO_CONFIG(X86_PAE);
 271 #endif
 272 }
 273