diff options
Diffstat (limited to 'arch/x86/kernel/machine_kexec_64.c')
| -rw-r--r-- | arch/x86/kernel/machine_kexec_64.c | 591 |
1 files changed, 591 insertions, 0 deletions
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c new file mode 100644 index 000000000..1a3e2c05a --- /dev/null +++ b/arch/x86/kernel/machine_kexec_64.c @@ -0,0 +1,591 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * handle transition of Linux booting another kernel + * Copyright (C) 2002-2005 Eric Biederman <ebiederm@xmission.com> + */ + +#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 <linux/efi.h> +#include <linux/cc_platform.h> + +#include <asm/init.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> +#include <asm/cpu.h> + +#ifdef CONFIG_ACPI +/* + * Used while adding mapping for ACPI tables. + * Can be reused when other iomem regions need be mapped + */ +struct init_pgtable_data { + struct x86_mapping_info *info; + pgd_t *level4p; +}; + +static int mem_region_callback(struct resource *res, void *arg) +{ + struct init_pgtable_data *data = arg; + unsigned long mstart, mend; + + mstart = res->start; + mend = mstart + resource_size(res) - 1; + + return kernel_ident_mapping_init(data->info, data->level4p, mstart, mend); +} + +static int +map_acpi_tables(struct x86_mapping_info *info, pgd_t *level4p) +{ + struct init_pgtable_data data; + unsigned long flags; + int ret; + + data.info = info; + data.level4p = level4p; + flags = IORESOURCE_MEM | IORESOURCE_BUSY; + + ret = walk_iomem_res_desc(IORES_DESC_ACPI_TABLES, flags, 0, -1, + &data, mem_region_callback); + if (ret && ret != -EINVAL) + return ret; + + /* ACPI tables could be located in ACPI Non-volatile Storage region */ + ret = walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1, + &data, mem_region_callback); + if (ret && ret != -EINVAL) + return ret; + + return 0; +} +#else +static int map_acpi_tables(struct x86_mapping_info *info, pgd_t *level4p) { return 0; } +#endif + +#ifdef CONFIG_KEXEC_FILE +const struct kexec_file_ops * const kexec_file_loaders[] = { + &kexec_bzImage64_ops, + NULL +}; +#endif + +static int +map_efi_systab(struct x86_mapping_info *info, pgd_t *level4p) +{ +#ifdef CONFIG_EFI + unsigned long mstart, mend; + + if (!efi_enabled(EFI_BOOT)) + return 0; + + mstart = (boot_params.efi_info.efi_systab | + ((u64)boot_params.efi_info.efi_systab_hi<<32)); + + if (efi_enabled(EFI_64BIT)) + mend = mstart + sizeof(efi_system_table_64_t); + else + mend = mstart + sizeof(efi_system_table_32_t); + + if (!mstart) + return 0; + + return kernel_ident_mapping_init(info, level4p, mstart, mend); +#endif + return 0; +} + +static void free_transition_pgtable(struct kimage *image) +{ + free_page((unsigned long)image->arch.p4d); + image->arch.p4d = NULL; + free_page((unsigned long)image->arch.pud); + image->arch.pud = NULL; + free_page((unsigned long)image->arch.pmd); + image->arch.pmd = NULL; + free_page((unsigned long)image->arch.pte); + image->arch.pte = NULL; +} + +static int init_transition_pgtable(struct kimage *image, pgd_t *pgd) +{ + pgprot_t prot = PAGE_KERNEL_EXEC_NOENC; + unsigned long vaddr, paddr; + int result = -ENOMEM; + p4d_t *p4d; + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + + 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); + + if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) + prot = PAGE_KERNEL_EXEC; + + set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, prot)); + return 0; +err: + 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 (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) { + info.page_flag |= _PAGE_ENC; + info.kernpg_flag |= _PAGE_ENC; + } + + 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; + } + + /* + * Prepare EFI systab and ACPI tables for kexec kernel since they are + * not covered by pfn_mapped. + */ + result = map_efi_systab(&info, level4p); + if (result) + return result; + + result = map_acpi_tables(&info, level4p); + if (result) + return result; + + return init_transition_pgtable(image, level4p); +} + +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" + ); +} + +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; + + 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(); + cet_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. + */ + native_idt_invalidate(); + native_gdt_invalidate(); + + /* now call it */ + image->start = relocate_kernel((unsigned long)image->head, + (unsigned long)page_list, + image->start, + image->preserve_context, + cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)); + +#ifdef CONFIG_KEXEC_JUMP + if (image->preserve_context) + restore_processor_state(); +#endif + + __ftrace_enabled_restore(save_ftrace_enabled); +} + +/* arch-dependent functionality related to kexec file-based syscall */ + +#ifdef CONFIG_KEXEC_FILE +/* + * 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; +} + +int arch_kimage_file_post_load_cleanup(struct kimage *image) +{ + vfree(image->elf_headers); + image->elf_headers = NULL; + image->elf_headers_sz = 0; + + return kexec_image_post_load_cleanup_default(image); +} +#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); +} + +/* + * During a traditional boot under SME, SME will encrypt the kernel, + * so the SME kexec kernel also needs to be un-encrypted in order to + * replicate a normal SME boot. + * + * During a traditional boot under SEV, the kernel has already been + * loaded encrypted, so the SEV kexec kernel needs to be encrypted in + * order to replicate a normal SEV boot. + */ +int arch_kexec_post_alloc_pages(void *vaddr, unsigned int pages, gfp_t gfp) +{ + if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) + return 0; + + /* + * If host memory encryption 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 (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) + return; + + /* + * If host memory encryption is active we need to reset the pages back + * to being an encrypted mapping before freeing them. + */ + set_memory_encrypted((unsigned long)vaddr, pages); +} |