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/numa.h>
  13 #include <linux/ftrace.h>
  14 #include <linux/suspend.h>
  15 #include <linux/gfp.h>
  16 #include <linux/io.h>
  17
  18 #include <asm/pgtable.h>
  19 #include <asm/pgalloc.h>
  20 #include <asm/tlbflush.h>
  21 #include <asm/mmu_context.h>
  22 #include <asm/apic.h>
  23 #include <asm/io_apic.h>
  24 #include <asm/cpufeature.h>
  25 #include <asm/desc.h>
  26 #include <asm/cacheflush.h>
  27 #include <asm/debugreg.h>
  28
  29 static void set_idt(void *newidt, __u16 limit)
  30 {
  31         struct desc_ptr curidt;
  32
  33         /* ia32 supports unaliged loads & stores */
  34         curidt.size    = limit;
  35         curidt.address = (unsigned long)newidt;
  36
  37         load_idt(&curidt);
  38 }
  39
  40
  41 static void set_gdt(void *newgdt, __u16 limit)
  42 {
  43         struct desc_ptr curgdt;
  44
  45         /* ia32 supports unaligned loads & stores */
  46         curgdt.size    = limit;
  47         curgdt.address = (unsigned long)newgdt;
  48
  49         load_gdt(&curgdt);
  50 }
  51
  52 static void load_segments(void)
  53 {
  54 #define __STR(X) #X
  55 #define STR(X) __STR(X)
  56
  57         __asm__ __volatile__ (
  58                 "\tljmp $"STR(__KERNEL_CS)",$1f\n"
  59                 "\t1:\n"
  60                 "\tmovl $"STR(__KERNEL_DS)",%%eax\n"
  61                 "\tmovl %%eax,%%ds\n"
  62                 "\tmovl %%eax,%%es\n"
  63                 "\tmovl %%eax,%%fs\n"
  64                 "\tmovl %%eax,%%gs\n"
  65                 "\tmovl %%eax,%%ss\n"
  66                 : : : "eax", "memory");
  67 #undef STR
  68 #undef __STR
  69 }
  70
  71 static void machine_kexec_free_page_tables(struct kimage *image)
  72 {
  73         free_page((unsigned long)image->arch.pgd);
  74         image->arch.pgd = NULL;
  75 #ifdef CONFIG_X86_PAE
  76         free_page((unsigned long)image->arch.pmd0);
  77         image->arch.pmd0 = NULL;
  78         free_page((unsigned long)image->arch.pmd1);
  79         image->arch.pmd1 = NULL;
  80 #endif
  81         free_page((unsigned long)image->arch.pte0);
  82         image->arch.pte0 = NULL;
  83         free_page((unsigned long)image->arch.pte1);
  84         image->arch.pte1 = NULL;
  85 }
  86
  87 static int machine_kexec_alloc_page_tables(struct kimage *image)
  88 {
  89         image->arch.pgd = (pgd_t *)get_zeroed_page(GFP_KERNEL);
  90 #ifdef CONFIG_X86_PAE
  91         image->arch.pmd0 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
  92         image->arch.pmd1 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
  93 #endif
  94         image->arch.pte0 = (pte_t *)get_zeroed_page(GFP_KERNEL);
  95         image->arch.pte1 = (pte_t *)get_zeroed_page(GFP_KERNEL);
  96         if (!image->arch.pgd ||
  97 #ifdef CONFIG_X86_PAE
  98             !image->arch.pmd0 || !image->arch.pmd1 ||
  99 #endif
 100             !image->arch.pte0 || !image->arch.pte1) {
 101                 return -ENOMEM;
 102         }
 103         return 0;
 104 }
 105
 106 static void machine_kexec_page_table_set_one(
 107         pgd_t *pgd, pmd_t *pmd, pte_t *pte,
 108         unsigned long vaddr, unsigned long paddr)
 109 {
 110         pud_t *pud;
 111
 112         pgd += pgd_index(vaddr);
 113 #ifdef CONFIG_X86_PAE
 114         if (!(pgd_val(*pgd) & _PAGE_PRESENT))
 115                 set_pgd(pgd, __pgd(__pa(pmd) | _PAGE_PRESENT));
 116 #endif
 117         pud = pud_offset(pgd, vaddr);
 118         pmd = pmd_offset(pud, vaddr);
 119         if (!(pmd_val(*pmd) & _PAGE_PRESENT))
 120                 set_pmd(pmd, __pmd(__pa(pte) | _PAGE_TABLE));
 121         pte = pte_offset_kernel(pmd, vaddr);
 122         set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
 123 }
 124
 125 static void machine_kexec_prepare_page_tables(struct kimage *image)
 126 {
 127         void *control_page;
 128         pmd_t *pmd = NULL;
 129
 130         control_page = page_address(image->control_code_page);
 131 #ifdef CONFIG_X86_PAE
 132         pmd = image->arch.pmd0;
 133 #endif
 134         machine_kexec_page_table_set_one(
 135                 image->arch.pgd, pmd, image->arch.pte0,
 136                 (unsigned long)control_page, __pa(control_page));
 137 #ifdef CONFIG_X86_PAE
 138         pmd = image->arch.pmd1;
 139 #endif
 140         machine_kexec_page_table_set_one(
 141                 image->arch.pgd, pmd, image->arch.pte1,
 142                 __pa(control_page), __pa(control_page));
 143 }
 144
 145 /*
 146  * A architecture hook called to validate the
 147  * proposed image and prepare the control pages
 148  * as needed.  The pages for KEXEC_CONTROL_PAGE_SIZE
 149  * have been allocated, but the segments have yet
 150  * been copied into the kernel.
 151  *
 152  * Do what every setup is needed on image and the
 153  * reboot code buffer to allow us to avoid allocations
 154  * later.
 155  *
 156  * - Make control page executable.
 157  * - Allocate page tables
 158  * - Setup page tables
 159  */
 160 int machine_kexec_prepare(struct kimage *image)
 161 {
 162         int error;
 163
 164         set_pages_x(image->control_code_page, 1);
 165         error = machine_kexec_alloc_page_tables(image);
 166         if (error)
 167                 return error;
 168         machine_kexec_prepare_page_tables(image);
 169         return 0;
 170 }
 171
 172 /*
 173  * Undo anything leftover by machine_kexec_prepare
 174  * when an image is freed.
 175  */
 176 void machine_kexec_cleanup(struct kimage *image)
 177 {
 178         set_pages_nx(image->control_code_page, 1);
 179         machine_kexec_free_page_tables(image);
 180 }
 181
 182 /*
 183  * Do not allocate memory (or fail in any way) in machine_kexec().
 184  * We are past the point of no return, committed to rebooting now.
 185  */
 186 void machine_kexec(struct kimage *image)
 187 {
 188         unsigned long page_list[PAGES_NR];
 189         void *control_page;
 190         int save_ftrace_enabled;
 191         asmlinkage unsigned long
 192                 (*relocate_kernel_ptr)(unsigned long indirection_page,
 193                                        unsigned long control_page,
 194                                        unsigned long start_address,
 195                                        unsigned int has_pae,
 196                                        unsigned int preserve_context);
 197
 198 #ifdef CONFIG_KEXEC_JUMP
 199         if (image->preserve_context)
 200                 save_processor_state();
 201 #endif
 202
 203         save_ftrace_enabled = __ftrace_enabled_save();
 204
 205         /* Interrupts aren't acceptable while we reboot */
 206         local_irq_disable();
 207         hw_breakpoint_disable();
 208
 209         if (image->preserve_context) {
 210 #ifdef CONFIG_X86_IO_APIC
 211                 /*
 212                  * We need to put APICs in legacy mode so that we can
 213                  * get timer interrupts in second kernel. kexec/kdump
 214                  * paths already have calls to disable_IO_APIC() in
 215                  * one form or other. kexec jump path also need
 216                  * one.
 217                  */
 218                 disable_IO_APIC();
 219 #endif
 220         }
 221
 222         control_page = page_address(image->control_code_page);
 223         memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
 224
 225         relocate_kernel_ptr = control_page;
 226         page_list[PA_CONTROL_PAGE] = __pa(control_page);
 227         page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
 228         page_list[PA_PGD] = __pa(image->arch.pgd);
 229
 230         if (image->type == KEXEC_TYPE_DEFAULT)
 231                 page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
 232                                                 << PAGE_SHIFT);
 233
 234         /*
 235          * The segment registers are funny things, they have both a
 236          * visible and an invisible part.  Whenever the visible part is
 237          * set to a specific selector, the invisible part is loaded
 238          * with from a table in memory.  At no other time is the
 239          * descriptor table in memory accessed.
 240          *
 241          * I take advantage of this here by force loading the
 242          * segments, before I zap the gdt with an invalid value.
 243          */
 244         load_segments();
 245         /*
 246          * The gdt & idt are now invalid.
 247          * If you want to load them you must set up your own idt & gdt.
 248          */
 249         set_gdt(phys_to_virt(0), 0);
 250         set_idt(phys_to_virt(0), 0);
 251
 252         /* now call it */
 253         image->start = relocate_kernel_ptr((unsigned long)image->head,
 254                                            (unsigned long)page_list,
 255                                            image->start,
 256                                            boot_cpu_has(X86_FEATURE_PAE),
 257                                            image->preserve_context);
 258
 259 #ifdef CONFIG_KEXEC_JUMP
 260         if (image->preserve_context)
 261                 restore_processor_state();
 262 #endif
 263
 264         __ftrace_enabled_restore(save_ftrace_enabled);
 265 }
 266
 267 void arch_crash_save_vmcoreinfo(void)
 268 {
 269 #ifdef CONFIG_NUMA
 270         VMCOREINFO_SYMBOL(node_data);
 271         VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
 272 #endif
 273 #ifdef CONFIG_X86_PAE
 274         VMCOREINFO_CONFIG(X86_PAE);
 275 #endif
 276 }
 277