diff options
Diffstat (limited to 'kernel/arch/x86/kernel/machine_kexec_64.c')
| -rw-r--r-- | kernel/arch/x86/kernel/machine_kexec_64.c | 536 |
1 files changed, 536 insertions, 0 deletions
diff --git a/kernel/arch/x86/kernel/machine_kexec_64.c b/kernel/arch/x86/kernel/machine_kexec_64.c new file mode 100644 index 000000000..415480d3e --- /dev/null +++ b/kernel/arch/x86/kernel/machine_kexec_64.c @@ -0,0 +1,536 @@ +/* + * handle transition of Linux booting another kernel + * Copyright (C) 2002-2005 Eric Biederman <ebiederm@xmission.com> + * + * This source code is licensed under the GNU General Public License, + * Version 2. See the file COPYING for more details. + */ + +#define pr_fmt(fmt) "kexec: " fmt + +#include <linux/mm.h> +#include <linux/kexec.h> +#include <linux/string.h> +#include <linux/gfp.h> +#include <linux/reboot.h> +#include <linux/numa.h> +#include <linux/ftrace.h> +#include <linux/io.h> +#include <linux/suspend.h> + +#include <asm/init.h> +#include <asm/pgtable.h> +#include <asm/tlbflush.h> +#include <asm/mmu_context.h> +#include <asm/io_apic.h> +#include <asm/debugreg.h> +#include <asm/kexec-bzimage64.h> + +#ifdef CONFIG_KEXEC_FILE +static struct kexec_file_ops *kexec_file_loaders[] = { + &kexec_bzImage64_ops, +}; +#endif + +static void free_transition_pgtable(struct kimage *image) +{ + free_page((unsigned long)image->arch.pud); + free_page((unsigned long)image->arch.pmd); + free_page((unsigned long)image->arch.pte); +} + +static int init_transition_pgtable(struct kimage *image, pgd_t *pgd) +{ + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + unsigned long vaddr, paddr; + int result = -ENOMEM; + + vaddr = (unsigned long)relocate_kernel; + paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE); + pgd += pgd_index(vaddr); + if (!pgd_present(*pgd)) { + pud = (pud_t *)get_zeroed_page(GFP_KERNEL); + if (!pud) + goto err; + image->arch.pud = pud; + set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE)); + } + pud = pud_offset(pgd, vaddr); + if (!pud_present(*pud)) { + pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL); + if (!pmd) + goto err; + image->arch.pmd = pmd; + set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE)); + } + pmd = pmd_offset(pud, vaddr); + if (!pmd_present(*pmd)) { + pte = (pte_t *)get_zeroed_page(GFP_KERNEL); + if (!pte) + goto err; + image->arch.pte = pte; + set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE)); + } + pte = pte_offset_kernel(pmd, vaddr); + set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC)); + return 0; +err: + free_transition_pgtable(image); + return result; +} + +static void *alloc_pgt_page(void *data) +{ + struct kimage *image = (struct kimage *)data; + struct page *page; + void *p = NULL; + + page = kimage_alloc_control_pages(image, 0); + if (page) { + p = page_address(page); + clear_page(p); + } + + return p; +} + +static int init_pgtable(struct kimage *image, unsigned long start_pgtable) +{ + struct x86_mapping_info info = { + .alloc_pgt_page = alloc_pgt_page, + .context = image, + .pmd_flag = __PAGE_KERNEL_LARGE_EXEC, + }; + unsigned long mstart, mend; + pgd_t *level4p; + int result; + int i; + + level4p = (pgd_t *)__va(start_pgtable); + clear_page(level4p); + for (i = 0; i < nr_pfn_mapped; i++) { + mstart = pfn_mapped[i].start << PAGE_SHIFT; + mend = pfn_mapped[i].end << PAGE_SHIFT; + + result = kernel_ident_mapping_init(&info, + level4p, mstart, mend); + if (result) + return result; + } + + /* + * segments's mem ranges could be outside 0 ~ max_pfn, + * for example when jump back to original kernel from kexeced kernel. + * or first kernel is booted with user mem map, and second kernel + * could be loaded out of that range. + */ + for (i = 0; i < image->nr_segments; i++) { + mstart = image->segment[i].mem; + mend = mstart + image->segment[i].memsz; + + result = kernel_ident_mapping_init(&info, + level4p, mstart, mend); + + if (result) + return result; + } + + return init_transition_pgtable(image, level4p); +} + +static void set_idt(void *newidt, u16 limit) +{ + struct desc_ptr curidt; + + /* x86-64 supports unaliged loads & stores */ + curidt.size = limit; + curidt.address = (unsigned long)newidt; + + __asm__ __volatile__ ( + "lidtq %0\n" + : : "m" (curidt) + ); +}; + + +static void set_gdt(void *newgdt, u16 limit) +{ + struct desc_ptr curgdt; + + /* x86-64 supports unaligned loads & stores */ + curgdt.size = limit; + curgdt.address = (unsigned long)newgdt; + + __asm__ __volatile__ ( + "lgdtq %0\n" + : : "m" (curgdt) + ); +}; + +static void load_segments(void) +{ + __asm__ __volatile__ ( + "\tmovl %0,%%ds\n" + "\tmovl %0,%%es\n" + "\tmovl %0,%%ss\n" + "\tmovl %0,%%fs\n" + "\tmovl %0,%%gs\n" + : : "a" (__KERNEL_DS) : "memory" + ); +} + +#ifdef CONFIG_KEXEC_FILE +/* Update purgatory as needed after various image segments have been prepared */ +static int arch_update_purgatory(struct kimage *image) +{ + int ret = 0; + + if (!image->file_mode) + return 0; + + /* Setup copying of backup region */ + if (image->type == KEXEC_TYPE_CRASH) { + ret = kexec_purgatory_get_set_symbol(image, "backup_dest", + &image->arch.backup_load_addr, + sizeof(image->arch.backup_load_addr), 0); + if (ret) + return ret; + + ret = kexec_purgatory_get_set_symbol(image, "backup_src", + &image->arch.backup_src_start, + sizeof(image->arch.backup_src_start), 0); + if (ret) + return ret; + + ret = kexec_purgatory_get_set_symbol(image, "backup_sz", + &image->arch.backup_src_sz, + sizeof(image->arch.backup_src_sz), 0); + if (ret) + return ret; + } + + return ret; +} +#else /* !CONFIG_KEXEC_FILE */ +static inline int arch_update_purgatory(struct kimage *image) +{ + return 0; +} +#endif /* CONFIG_KEXEC_FILE */ + +int machine_kexec_prepare(struct kimage *image) +{ + unsigned long start_pgtable; + int result; + + /* Calculate the offsets */ + start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT; + + /* Setup the identity mapped 64bit page table */ + result = init_pgtable(image, start_pgtable); + if (result) + return result; + + /* update purgatory as needed */ + result = arch_update_purgatory(image); + if (result) + return result; + + return 0; +} + +void machine_kexec_cleanup(struct kimage *image) +{ + free_transition_pgtable(image); +} + +/* + * Do not allocate memory (or fail in any way) in machine_kexec(). + * We are past the point of no return, committed to rebooting now. + */ +void machine_kexec(struct kimage *image) +{ + unsigned long page_list[PAGES_NR]; + void *control_page; + int save_ftrace_enabled; + +#ifdef CONFIG_KEXEC_JUMP + if (image->preserve_context) + save_processor_state(); +#endif + + save_ftrace_enabled = __ftrace_enabled_save(); + + /* Interrupts aren't acceptable while we reboot */ + local_irq_disable(); + hw_breakpoint_disable(); + + if (image->preserve_context) { +#ifdef CONFIG_X86_IO_APIC + /* + * We need to put APICs in legacy mode so that we can + * get timer interrupts in second kernel. kexec/kdump + * paths already have calls to disable_IO_APIC() in + * one form or other. kexec jump path also need + * one. + */ + disable_IO_APIC(); +#endif + } + + control_page = page_address(image->control_code_page) + PAGE_SIZE; + memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE); + + page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page); + page_list[VA_CONTROL_PAGE] = (unsigned long)control_page; + page_list[PA_TABLE_PAGE] = + (unsigned long)__pa(page_address(image->control_code_page)); + + if (image->type == KEXEC_TYPE_DEFAULT) + page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page) + << PAGE_SHIFT); + + /* + * The segment registers are funny things, they have both a + * visible and an invisible part. Whenever the visible part is + * set to a specific selector, the invisible part is loaded + * with from a table in memory. At no other time is the + * descriptor table in memory accessed. + * + * I take advantage of this here by force loading the + * segments, before I zap the gdt with an invalid value. + */ + load_segments(); + /* + * The gdt & idt are now invalid. + * If you want to load them you must set up your own idt & gdt. + */ + set_gdt(phys_to_virt(0), 0); + set_idt(phys_to_virt(0), 0); + + /* now call it */ + image->start = relocate_kernel((unsigned long)image->head, + (unsigned long)page_list, + image->start, + image->preserve_context); + +#ifdef CONFIG_KEXEC_JUMP + if (image->preserve_context) + restore_processor_state(); +#endif + + __ftrace_enabled_restore(save_ftrace_enabled); +} + +void arch_crash_save_vmcoreinfo(void) +{ + VMCOREINFO_SYMBOL(phys_base); + VMCOREINFO_SYMBOL(init_level4_pgt); + +#ifdef CONFIG_NUMA + VMCOREINFO_SYMBOL(node_data); + VMCOREINFO_LENGTH(node_data, MAX_NUMNODES); +#endif + vmcoreinfo_append_str("KERNELOFFSET=%lx\n", + (unsigned long)&_text - __START_KERNEL); +} + +/* arch-dependent functionality related to kexec file-based syscall */ + +#ifdef CONFIG_KEXEC_FILE +int arch_kexec_kernel_image_probe(struct kimage *image, void *buf, + unsigned long buf_len) +{ + int i, ret = -ENOEXEC; + struct kexec_file_ops *fops; + + for (i = 0; i < ARRAY_SIZE(kexec_file_loaders); i++) { + fops = kexec_file_loaders[i]; + if (!fops || !fops->probe) + continue; + + ret = fops->probe(buf, buf_len); + if (!ret) { + image->fops = fops; + return ret; + } + } + + return ret; +} + +void *arch_kexec_kernel_image_load(struct kimage *image) +{ + vfree(image->arch.elf_headers); + image->arch.elf_headers = NULL; + + if (!image->fops || !image->fops->load) + return ERR_PTR(-ENOEXEC); + + return image->fops->load(image, image->kernel_buf, + image->kernel_buf_len, image->initrd_buf, + image->initrd_buf_len, image->cmdline_buf, + image->cmdline_buf_len); +} + +int arch_kimage_file_post_load_cleanup(struct kimage *image) +{ + if (!image->fops || !image->fops->cleanup) + return 0; + + return image->fops->cleanup(image->image_loader_data); +} + +int arch_kexec_kernel_verify_sig(struct kimage *image, void *kernel, + unsigned long kernel_len) +{ + if (!image->fops || !image->fops->verify_sig) { + pr_debug("kernel loader does not support signature verification."); + return -EKEYREJECTED; + } + + return image->fops->verify_sig(kernel, kernel_len); +} + +/* + * Apply purgatory relocations. + * + * ehdr: Pointer to elf headers + * sechdrs: Pointer to section headers. + * relsec: section index of SHT_RELA section. + * + * TODO: Some of the code belongs to generic code. Move that in kexec.c. + */ +int arch_kexec_apply_relocations_add(const Elf64_Ehdr *ehdr, + Elf64_Shdr *sechdrs, unsigned int relsec) +{ + unsigned int i; + Elf64_Rela *rel; + Elf64_Sym *sym; + void *location; + Elf64_Shdr *section, *symtabsec; + unsigned long address, sec_base, value; + const char *strtab, *name, *shstrtab; + + /* + * ->sh_offset has been modified to keep the pointer to section + * contents in memory + */ + rel = (void *)sechdrs[relsec].sh_offset; + + /* Section to which relocations apply */ + section = &sechdrs[sechdrs[relsec].sh_info]; + + pr_debug("Applying relocate section %u to %u\n", relsec, + sechdrs[relsec].sh_info); + + /* Associated symbol table */ + symtabsec = &sechdrs[sechdrs[relsec].sh_link]; + + /* String table */ + if (symtabsec->sh_link >= ehdr->e_shnum) { + /* Invalid strtab section number */ + pr_err("Invalid string table section index %d\n", + symtabsec->sh_link); + return -ENOEXEC; + } + + strtab = (char *)sechdrs[symtabsec->sh_link].sh_offset; + + /* section header string table */ + shstrtab = (char *)sechdrs[ehdr->e_shstrndx].sh_offset; + + for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { + + /* + * rel[i].r_offset contains byte offset from beginning + * of section to the storage unit affected. + * + * This is location to update (->sh_offset). This is temporary + * buffer where section is currently loaded. This will finally + * be loaded to a different address later, pointed to by + * ->sh_addr. kexec takes care of moving it + * (kexec_load_segment()). + */ + location = (void *)(section->sh_offset + rel[i].r_offset); + + /* Final address of the location */ + address = section->sh_addr + rel[i].r_offset; + + /* + * rel[i].r_info contains information about symbol table index + * w.r.t which relocation must be made and type of relocation + * to apply. ELF64_R_SYM() and ELF64_R_TYPE() macros get + * these respectively. + */ + sym = (Elf64_Sym *)symtabsec->sh_offset + + ELF64_R_SYM(rel[i].r_info); + + if (sym->st_name) + name = strtab + sym->st_name; + else + name = shstrtab + sechdrs[sym->st_shndx].sh_name; + + pr_debug("Symbol: %s info: %02x shndx: %02x value=%llx size: %llx\n", + name, sym->st_info, sym->st_shndx, sym->st_value, + sym->st_size); + + if (sym->st_shndx == SHN_UNDEF) { + pr_err("Undefined symbol: %s\n", name); + return -ENOEXEC; + } + + if (sym->st_shndx == SHN_COMMON) { + pr_err("symbol '%s' in common section\n", name); + return -ENOEXEC; + } + + if (sym->st_shndx == SHN_ABS) + sec_base = 0; + else if (sym->st_shndx >= ehdr->e_shnum) { + pr_err("Invalid section %d for symbol %s\n", + sym->st_shndx, name); + return -ENOEXEC; + } else + sec_base = sechdrs[sym->st_shndx].sh_addr; + + value = sym->st_value; + value += sec_base; + value += rel[i].r_addend; + + switch (ELF64_R_TYPE(rel[i].r_info)) { + case R_X86_64_NONE: + break; + case R_X86_64_64: + *(u64 *)location = value; + break; + case R_X86_64_32: + *(u32 *)location = value; + if (value != *(u32 *)location) + goto overflow; + break; + case R_X86_64_32S: + *(s32 *)location = value; + if ((s64)value != *(s32 *)location) + goto overflow; + break; + case R_X86_64_PC32: + value -= (u64)address; + *(u32 *)location = value; + break; + default: + pr_err("Unknown rela relocation: %llu\n", + ELF64_R_TYPE(rel[i].r_info)); + return -ENOEXEC; + } + } + return 0; + +overflow: + pr_err("Overflow in relocation type %d value 0x%lx\n", + (int)ELF64_R_TYPE(rel[i].r_info), value); + return -ENOEXEC; +} +#endif /* CONFIG_KEXEC_FILE */ |