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