| /* |
| * 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 <linux/vmalloc.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> |
| #include <asm/setup.h> |
| #include <asm/set_memory.h> |
| |
| #ifdef CONFIG_KEXEC_FILE |
| const struct kexec_file_ops * const kexec_file_loaders[] = { |
| &kexec_bzImage64_ops, |
| NULL |
| }; |
| #endif |
| |
| static void free_transition_pgtable(struct kimage *image) |
| { |
| free_page((unsigned long)image->arch.p4d); |
| 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) |
| { |
| p4d_t *p4d; |
| 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)) { |
| p4d = (p4d_t *)get_zeroed_page(GFP_KERNEL); |
| if (!p4d) |
| goto err; |
| image->arch.p4d = p4d; |
| set_pgd(pgd, __pgd(__pa(p4d) | _KERNPG_TABLE)); |
| } |
| p4d = p4d_offset(pgd, vaddr); |
| if (!p4d_present(*p4d)) { |
| pud = (pud_t *)get_zeroed_page(GFP_KERNEL); |
| if (!pud) |
| goto err; |
| image->arch.pud = pud; |
| set_p4d(p4d, __p4d(__pa(pud) | _KERNPG_TABLE)); |
| } |
| pud = pud_offset(p4d, 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_NOENC)); |
| 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, |
| .page_flag = __PAGE_KERNEL_LARGE_EXEC, |
| .kernpg_flag = _KERNPG_TABLE_NOENC, |
| }; |
| unsigned long mstart, mend; |
| pgd_t *level4p; |
| int result; |
| int i; |
| |
| level4p = (pgd_t *)__va(start_pgtable); |
| clear_page(level4p); |
| |
| if (direct_gbpages) |
| info.direct_gbpages = true; |
| |
| 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, |
| "purgatory_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, |
| "purgatory_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, |
| "purgatory_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 restore_boot_irq_mode() |
| * in one form or other. kexec jump path also need one. |
| */ |
| clear_IO_APIC(); |
| restore_boot_irq_mode(); |
| #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, |
| sme_active()); |
| |
| #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_NUMBER(phys_base); |
| VMCOREINFO_SYMBOL(init_top_pgt); |
| VMCOREINFO_NUMBER(pgtable_l5_enabled); |
| |
| #ifdef CONFIG_NUMA |
| VMCOREINFO_SYMBOL(node_data); |
| VMCOREINFO_LENGTH(node_data, MAX_NUMNODES); |
| #endif |
| vmcoreinfo_append_str("KERNELOFFSET=%lx\n", |
| kaslr_offset()); |
| VMCOREINFO_NUMBER(KERNEL_IMAGE_SIZE); |
| } |
| |
| /* arch-dependent functionality related to kexec file-based syscall */ |
| |
| #ifdef CONFIG_KEXEC_FILE |
| 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); |
| } |
| |
| /* |
| * Apply purgatory relocations. |
| * |
| * @pi: Purgatory to be relocated. |
| * @section: Section relocations applying to. |
| * @relsec: Section containing RELAs. |
| * @symtabsec: Corresponding symtab. |
| * |
| * TODO: Some of the code belongs to generic code. Move that in kexec.c. |
| */ |
| int arch_kexec_apply_relocations_add(struct purgatory_info *pi, |
| Elf_Shdr *section, const Elf_Shdr *relsec, |
| const Elf_Shdr *symtabsec) |
| { |
| unsigned int i; |
| Elf64_Rela *rel; |
| Elf64_Sym *sym; |
| void *location; |
| unsigned long address, sec_base, value; |
| const char *strtab, *name, *shstrtab; |
| const Elf_Shdr *sechdrs; |
| |
| /* String & section header string table */ |
| sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff; |
| strtab = (char *)pi->ehdr + sechdrs[symtabsec->sh_link].sh_offset; |
| shstrtab = (char *)pi->ehdr + sechdrs[pi->ehdr->e_shstrndx].sh_offset; |
| |
| rel = (void *)pi->ehdr + relsec->sh_offset; |
| |
| pr_debug("Applying relocate section %s to %u\n", |
| shstrtab + relsec->sh_name, relsec->sh_info); |
| |
| for (i = 0; i < 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. 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 = pi->purgatory_buf; |
| location += section->sh_offset; |
| location += 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 = (void *)pi->ehdr + symtabsec->sh_offset; |
| sym += 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 >= pi->ehdr->e_shnum) { |
| pr_err("Invalid section %d for symbol %s\n", |
| sym->st_shndx, name); |
| return -ENOEXEC; |
| } else |
| sec_base = pi->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: |
| case R_X86_64_PLT32: |
| 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 */ |
| |
| static int |
| kexec_mark_range(unsigned long start, unsigned long end, bool protect) |
| { |
| struct page *page; |
| unsigned int nr_pages; |
| |
| /* |
| * For physical range: [start, end]. We must skip the unassigned |
| * crashk resource with zero-valued "end" member. |
| */ |
| if (!end || start > end) |
| return 0; |
| |
| page = pfn_to_page(start >> PAGE_SHIFT); |
| nr_pages = (end >> PAGE_SHIFT) - (start >> PAGE_SHIFT) + 1; |
| if (protect) |
| return set_pages_ro(page, nr_pages); |
| else |
| return set_pages_rw(page, nr_pages); |
| } |
| |
| static void kexec_mark_crashkres(bool protect) |
| { |
| unsigned long control; |
| |
| kexec_mark_range(crashk_low_res.start, crashk_low_res.end, protect); |
| |
| /* Don't touch the control code page used in crash_kexec().*/ |
| control = PFN_PHYS(page_to_pfn(kexec_crash_image->control_code_page)); |
| /* Control code page is located in the 2nd page. */ |
| kexec_mark_range(crashk_res.start, control + PAGE_SIZE - 1, protect); |
| control += KEXEC_CONTROL_PAGE_SIZE; |
| kexec_mark_range(control, crashk_res.end, protect); |
| } |
| |
| void arch_kexec_protect_crashkres(void) |
| { |
| kexec_mark_crashkres(true); |
| } |
| |
| void arch_kexec_unprotect_crashkres(void) |
| { |
| kexec_mark_crashkres(false); |
| } |
| |
| int arch_kexec_post_alloc_pages(void *vaddr, unsigned int pages, gfp_t gfp) |
| { |
| /* |
| * If SME is active we need to be sure that kexec pages are |
| * not encrypted because when we boot to the new kernel the |
| * pages won't be accessed encrypted (initially). |
| */ |
| return set_memory_decrypted((unsigned long)vaddr, pages); |
| } |
| |
| void arch_kexec_pre_free_pages(void *vaddr, unsigned int pages) |
| { |
| /* |
| * If SME is active we need to reset the pages back to being |
| * an encrypted mapping before freeing them. |
| */ |
| set_memory_encrypted((unsigned long)vaddr, pages); |
| } |