1 files changed, 483 insertions, 0 deletions
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
new file mode 100644
index 000000000..91b3483e5
--- /dev/null
+++ b/arch/x86/kernel/crash.c
@@ -0,0 +1,483 @@
+/*
+ * Architecture specific (i386/x86_64) functions for kexec based crash dumps.
+ *
+ * Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
+ *
+ * Copyright (C) IBM Corporation, 2004. All rights reserved.
+ * Copyright (C) Red Hat Inc., 2014. All rights reserved.
+ * Authors:
+ *      Vivek Goyal <vgoyal@redhat.com>
+ *
+ */
+
+#define pr_fmt(fmt)	"kexec: " fmt
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/smp.h>
+#include <linux/reboot.h>
+#include <linux/kexec.h>
+#include <linux/delay.h>
+#include <linux/elf.h>
+#include <linux/elfcore.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+
+#include <asm/processor.h>
+#include <asm/hardirq.h>
+#include <asm/nmi.h>
+#include <asm/hw_irq.h>
+#include <asm/apic.h>
+#include <asm/e820/types.h>
+#include <asm/io_apic.h>
+#include <asm/hpet.h>
+#include <linux/kdebug.h>
+#include <asm/cpu.h>
+#include <asm/reboot.h>
+#include <asm/virtext.h>
+#include <asm/intel_pt.h>
+
+/* Used while preparing memory map entries for second kernel */
+struct crash_memmap_data {
+	struct boot_params *params;
+	/* Type of memory */
+	unsigned int type;
+};
+
+/*
+ * This is used to VMCLEAR all VMCSs loaded on the
+ * processor. And when loading kvm_intel module, the
+ * callback function pointer will be assigned.
+ *
+ * protected by rcu.
+ */
+crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss = NULL;
+EXPORT_SYMBOL_GPL(crash_vmclear_loaded_vmcss);
+unsigned long crash_zero_bytes;
+
+static inline void cpu_crash_vmclear_loaded_vmcss(void)
+{
+	crash_vmclear_fn *do_vmclear_operation = NULL;
+
+	rcu_read_lock();
+	do_vmclear_operation = rcu_dereference(crash_vmclear_loaded_vmcss);
+	if (do_vmclear_operation)
+		do_vmclear_operation();
+	rcu_read_unlock();
+}
+
+#if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
+
+static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
+{
+#ifdef CONFIG_X86_32
+	struct pt_regs fixed_regs;
+
+	if (!user_mode(regs)) {
+		crash_fixup_ss_esp(&fixed_regs, regs);
+		regs = &fixed_regs;
+	}
+#endif
+	crash_save_cpu(regs, cpu);
+
+	/*
+	 * VMCLEAR VMCSs loaded on all cpus if needed.
+	 */
+	cpu_crash_vmclear_loaded_vmcss();
+
+	/* Disable VMX or SVM if needed.
+	 *
+	 * We need to disable virtualization on all CPUs.
+	 * Having VMX or SVM enabled on any CPU may break rebooting
+	 * after the kdump kernel has finished its task.
+	 */
+	cpu_emergency_vmxoff();
+	cpu_emergency_svm_disable();
+
+	/*
+	 * Disable Intel PT to stop its logging
+	 */
+	cpu_emergency_stop_pt();
+
+	disable_local_APIC();
+}
+
+void kdump_nmi_shootdown_cpus(void)
+{
+	nmi_shootdown_cpus(kdump_nmi_callback);
+
+	disable_local_APIC();
+}
+
+/* Override the weak function in kernel/panic.c */
+void crash_smp_send_stop(void)
+{
+	static int cpus_stopped;
+
+	if (cpus_stopped)
+		return;
+
+	if (smp_ops.crash_stop_other_cpus)
+		smp_ops.crash_stop_other_cpus();
+	else
+		smp_send_stop();
+
+	cpus_stopped = 1;
+}
+
+#else
+void crash_smp_send_stop(void)
+{
+	/* There are no cpus to shootdown */
+}
+#endif
+
+void native_machine_crash_shutdown(struct pt_regs *regs)
+{
+	/* This function is only called after the system
+	 * has panicked or is otherwise in a critical state.
+	 * The minimum amount of code to allow a kexec'd kernel
+	 * to run successfully needs to happen here.
+	 *
+	 * In practice this means shooting down the other cpus in
+	 * an SMP system.
+	 */
+	/* The kernel is broken so disable interrupts */
+	local_irq_disable();
+
+	crash_smp_send_stop();
+
+	/*
+	 * VMCLEAR VMCSs loaded on this cpu if needed.
+	 */
+	cpu_crash_vmclear_loaded_vmcss();
+
+	/* Booting kdump kernel with VMX or SVM enabled won't work,
+	 * because (among other limitations) we can't disable paging
+	 * with the virt flags.
+	 */
+	cpu_emergency_vmxoff();
+	cpu_emergency_svm_disable();
+
+	/*
+	 * Disable Intel PT to stop its logging
+	 */
+	cpu_emergency_stop_pt();
+
+#ifdef CONFIG_X86_IO_APIC
+	/* Prevent crash_kexec() from deadlocking on ioapic_lock. */
+	ioapic_zap_locks();
+	clear_IO_APIC();
+#endif
+	lapic_shutdown();
+	restore_boot_irq_mode();
+#ifdef CONFIG_HPET_TIMER
+	hpet_disable();
+#endif
+	crash_save_cpu(regs, safe_smp_processor_id());
+}
+
+#ifdef CONFIG_KEXEC_FILE
+static int get_nr_ram_ranges_callback(struct resource *res, void *arg)
+{
+	unsigned int *nr_ranges = arg;
+
+	(*nr_ranges)++;
+	return 0;
+}
+
+/* Gather all the required information to prepare elf headers for ram regions */
+static struct crash_mem *fill_up_crash_elf_data(void)
+{
+	unsigned int nr_ranges = 0;
+	struct crash_mem *cmem;
+
+	walk_system_ram_res(0, -1, &nr_ranges,
+				get_nr_ram_ranges_callback);
+	if (!nr_ranges)
+		return NULL;
+
+	/*
+	 * Exclusion of crash region and/or crashk_low_res may cause
+	 * another range split. So add extra two slots here.
+	 */
+	nr_ranges += 2;
+	cmem = vzalloc(sizeof(struct crash_mem) +
+			sizeof(struct crash_mem_range) * nr_ranges);
+	if (!cmem)
+		return NULL;
+
+	cmem->max_nr_ranges = nr_ranges;
+	cmem->nr_ranges = 0;
+
+	return cmem;
+}
+
+/*
+ * Look for any unwanted ranges between mstart, mend and remove them. This
+ * might lead to split and split ranges are put in cmem->ranges[] array
+ */
+static int elf_header_exclude_ranges(struct crash_mem *cmem)
+{
+	int ret = 0;
+
+	/* Exclude crashkernel region */
+	ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
+	if (ret)
+		return ret;
+
+	if (crashk_low_res.end) {
+		ret = crash_exclude_mem_range(cmem, crashk_low_res.start,
+							crashk_low_res.end);
+		if (ret)
+			return ret;
+	}
+
+	return ret;
+}
+
+static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
+{
+	struct crash_mem *cmem = arg;
+
+	cmem->ranges[cmem->nr_ranges].start = res->start;
+	cmem->ranges[cmem->nr_ranges].end = res->end;
+	cmem->nr_ranges++;
+
+	return 0;
+}
+
+/* Prepare elf headers. Return addr and size */
+static int prepare_elf_headers(struct kimage *image, void **addr,
+					unsigned long *sz)
+{
+	struct crash_mem *cmem;
+	Elf64_Ehdr *ehdr;
+	Elf64_Phdr *phdr;
+	int ret, i;
+
+	cmem = fill_up_crash_elf_data();
+	if (!cmem)
+		return -ENOMEM;
+
+	ret = walk_system_ram_res(0, -1, cmem,
+				prepare_elf64_ram_headers_callback);
+	if (ret)
+		goto out;
+
+	/* Exclude unwanted mem ranges */
+	ret = elf_header_exclude_ranges(cmem);
+	if (ret)
+		goto out;
+
+	/* By default prepare 64bit headers */
+	ret =  crash_prepare_elf64_headers(cmem,
+				IS_ENABLED(CONFIG_X86_64), addr, sz);
+	if (ret)
+		goto out;
+
+	/*
+	 * If a range matches backup region, adjust offset to backup
+	 * segment.
+	 */
+	ehdr = (Elf64_Ehdr *)*addr;
+	phdr = (Elf64_Phdr *)(ehdr + 1);
+	for (i = 0; i < ehdr->e_phnum; phdr++, i++)
+		if (phdr->p_type == PT_LOAD &&
+				phdr->p_paddr == image->arch.backup_src_start &&
+				phdr->p_memsz == image->arch.backup_src_sz) {
+			phdr->p_offset = image->arch.backup_load_addr;
+			break;
+		}
+out:
+	vfree(cmem);
+	return ret;
+}
+
+static int add_e820_entry(struct boot_params *params, struct e820_entry *entry)
+{
+	unsigned int nr_e820_entries;
+
+	nr_e820_entries = params->e820_entries;
+	if (nr_e820_entries >= E820_MAX_ENTRIES_ZEROPAGE)
+		return 1;
+
+	memcpy(&params->e820_table[nr_e820_entries], entry,
+			sizeof(struct e820_entry));
+	params->e820_entries++;
+	return 0;
+}
+
+static int memmap_entry_callback(struct resource *res, void *arg)
+{
+	struct crash_memmap_data *cmd = arg;
+	struct boot_params *params = cmd->params;
+	struct e820_entry ei;
+
+	ei.addr = res->start;
+	ei.size = resource_size(res);
+	ei.type = cmd->type;
+	add_e820_entry(params, &ei);
+
+	return 0;
+}
+
+static int memmap_exclude_ranges(struct kimage *image, struct crash_mem *cmem,
+				 unsigned long long mstart,
+				 unsigned long long mend)
+{
+	unsigned long start, end;
+	int ret = 0;
+
+	cmem->ranges[0].start = mstart;
+	cmem->ranges[0].end = mend;
+	cmem->nr_ranges = 1;
+
+	/* Exclude Backup region */
+	start = image->arch.backup_load_addr;
+	end = start + image->arch.backup_src_sz - 1;
+	ret = crash_exclude_mem_range(cmem, start, end);
+	if (ret)
+		return ret;
+
+	/* Exclude elf header region */
+	start = image->arch.elf_load_addr;
+	end = start + image->arch.elf_headers_sz - 1;
+	return crash_exclude_mem_range(cmem, start, end);
+}
+
+/* Prepare memory map for crash dump kernel */
+int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
+{
+	int i, ret = 0;
+	unsigned long flags;
+	struct e820_entry ei;
+	struct crash_memmap_data cmd;
+	struct crash_mem *cmem;
+
+	cmem = vzalloc(struct_size(cmem, ranges, 1));
+	if (!cmem)
+		return -ENOMEM;
+
+	memset(&cmd, 0, sizeof(struct crash_memmap_data));
+	cmd.params = params;
+
+	/* Add first 640K segment */
+	ei.addr = image->arch.backup_src_start;
+	ei.size = image->arch.backup_src_sz;
+	ei.type = E820_TYPE_RAM;
+	add_e820_entry(params, &ei);
+
+	/* Add ACPI tables */
+	cmd.type = E820_TYPE_ACPI;
+	flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+	walk_iomem_res_desc(IORES_DESC_ACPI_TABLES, flags, 0, -1, &cmd,
+		       memmap_entry_callback);
+
+	/* Add ACPI Non-volatile Storage */
+	cmd.type = E820_TYPE_NVS;
+	walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1, &cmd,
+			memmap_entry_callback);
+
+	/* Add crashk_low_res region */
+	if (crashk_low_res.end) {
+		ei.addr = crashk_low_res.start;
+		ei.size = crashk_low_res.end - crashk_low_res.start + 1;
+		ei.type = E820_TYPE_RAM;
+		add_e820_entry(params, &ei);
+	}
+
+	/* Exclude some ranges from crashk_res and add rest to memmap */
+	ret = memmap_exclude_ranges(image, cmem, crashk_res.start,
+						crashk_res.end);
+	if (ret)
+		goto out;
+
+	for (i = 0; i < cmem->nr_ranges; i++) {
+		ei.size = cmem->ranges[i].end - cmem->ranges[i].start + 1;
+
+		/* If entry is less than a page, skip it */
+		if (ei.size < PAGE_SIZE)
+			continue;
+		ei.addr = cmem->ranges[i].start;
+		ei.type = E820_TYPE_RAM;
+		add_e820_entry(params, &ei);
+	}
+
+out:
+	vfree(cmem);
+	return ret;
+}
+
+static int determine_backup_region(struct resource *res, void *arg)
+{
+	struct kimage *image = arg;
+
+	image->arch.backup_src_start = res->start;
+	image->arch.backup_src_sz = resource_size(res);
+
+	/* Expecting only one range for backup region */
+	return 1;
+}
+
+int crash_load_segments(struct kimage *image)
+{
+	int ret;
+	struct kexec_buf kbuf = { .image = image, .buf_min = 0,
+				  .buf_max = ULONG_MAX, .top_down = false };
+
+	/*
+	 * Determine and load a segment for backup area. First 640K RAM
+	 * region is backup source
+	 */
+
+	ret = walk_system_ram_res(KEXEC_BACKUP_SRC_START, KEXEC_BACKUP_SRC_END,
+				image, determine_backup_region);
+
+	/* Zero or postive return values are ok */
+	if (ret < 0)
+		return ret;
+
+	/* Add backup segment. */
+	if (image->arch.backup_src_sz) {
+		kbuf.buffer = &crash_zero_bytes;
+		kbuf.bufsz = sizeof(crash_zero_bytes);
+		kbuf.memsz = image->arch.backup_src_sz;
+		kbuf.buf_align = PAGE_SIZE;
+		/*
+		 * Ideally there is no source for backup segment. This is
+		 * copied in purgatory after crash. Just add a zero filled
+		 * segment for now to make sure checksum logic works fine.
+		 */
+		ret = kexec_add_buffer(&kbuf);
+		if (ret)
+			return ret;
+		image->arch.backup_load_addr = kbuf.mem;
+		pr_debug("Loaded backup region at 0x%lx backup_start=0x%lx memsz=0x%lx\n",
+			 image->arch.backup_load_addr,
+			 image->arch.backup_src_start, kbuf.memsz);
+	}
+
+	/* Prepare elf headers and add a segment */
+	ret = prepare_elf_headers(image, &kbuf.buffer, &kbuf.bufsz);
+	if (ret)
+		return ret;
+
+	image->arch.elf_headers = kbuf.buffer;
+	image->arch.elf_headers_sz = kbuf.bufsz;
+
+	kbuf.memsz = kbuf.bufsz;
+	kbuf.buf_align = ELF_CORE_HEADER_ALIGN;
+	ret = kexec_add_buffer(&kbuf);
+	if (ret) {
+		vfree((void *)image->arch.elf_headers);
+		return ret;
+	}
+	image->arch.elf_load_addr = kbuf.mem;
+	pr_debug("Loaded ELF headers at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
+		 image->arch.elf_load_addr, kbuf.bufsz, kbuf.bufsz);
+
+	return ret;
+}
+#endif /* CONFIG_KEXEC_FILE */