initial Olimex linux tree from Daniel, originally Feb 3, 2016

1 files changed, 536 insertions, 0 deletions

diff --git a/linux/arch/x86/kernel/machine_kexec_64.c b/linux/arch/x86/kernel/machine_kexec_64.c
new file mode 100644
index 00000000..415480d3
--- /dev/null
+++ b/linux/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 */