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Diffstat (limited to 'arch/x86/kernel/machine_kexec_64.c')
-rw-r--r--arch/x86/kernel/machine_kexec_64.c602
1 files changed, 602 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..0611fd838
--- /dev/null
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -0,0 +1,602 @@
+// 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
+void *arch_kexec_kernel_image_load(struct kimage *image)
+{
+ 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;
+}
+
+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);
+}