1 files changed, 494 insertions, 0 deletions
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
new file mode 100644
index 0000000000..c92d88680d
--- /dev/null
+++ b/arch/x86/kernel/crash.c
@@ -0,0 +1,494 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * 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 <linux/memblock.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/intel_pt.h>
+#include <asm/crash.h>
+#include <asm/cmdline.h>
+
+/* Used while preparing memory map entries for second kernel */
+struct crash_memmap_data {
+	struct boot_params *params;
+	/* Type of memory */
+	unsigned int type;
+};
+
+#if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
+
+static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
+{
+	crash_save_cpu(regs, cpu);
+
+	/*
+	 * 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();
+
+	cpu_emergency_disable_virtualization();
+
+	/*
+	 * 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());
+}
+
+#if defined(CONFIG_KEXEC_FILE) || defined(CONFIG_CRASH_HOTPLUG)
+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(struct_size(cmem, ranges, 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 the low 1M because it is always reserved */
+	ret = crash_exclude_mem_range(cmem, 0, (1<<20)-1);
+	if (ret)
+		return ret;
+
+	/* 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);
+
+	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, unsigned long *nr_mem_ranges)
+{
+	struct crash_mem *cmem;
+	int ret;
+
+	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;
+
+	/* Return the computed number of memory ranges, for hotplug usage */
+	*nr_mem_ranges = cmem->nr_ranges;
+
+	/* By default prepare 64bit headers */
+	ret =  crash_prepare_elf64_headers(cmem, IS_ENABLED(CONFIG_X86_64), addr, sz);
+
+out:
+	vfree(cmem);
+	return ret;
+}
+#endif
+
+#ifdef CONFIG_KEXEC_FILE
+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;
+
+	cmem->ranges[0].start = mstart;
+	cmem->ranges[0].end = mend;
+	cmem->nr_ranges = 1;
+
+	/* Exclude elf header region */
+	start = image->elf_load_addr;
+	end = start + image->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 the low 1M */
+	cmd.type = E820_TYPE_RAM;
+	flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
+	walk_iomem_res_desc(IORES_DESC_NONE, flags, 0, (1<<20)-1, &cmd,
+			    memmap_entry_callback);
+
+	/* 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 e820 reserved ranges */
+	cmd.type = E820_TYPE_RESERVED;
+	flags = IORESOURCE_MEM;
+	walk_iomem_res_desc(IORES_DESC_RESERVED, 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 = resource_size(&crashk_low_res);
+		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;
+}
+
+int crash_load_segments(struct kimage *image)
+{
+	int ret;
+	unsigned long pnum = 0;
+	struct kexec_buf kbuf = { .image = image, .buf_min = 0,
+				  .buf_max = ULONG_MAX, .top_down = false };
+
+	/* Prepare elf headers and add a segment */
+	ret = prepare_elf_headers(image, &kbuf.buffer, &kbuf.bufsz, &pnum);
+	if (ret)
+		return ret;
+
+	image->elf_headers	= kbuf.buffer;
+	image->elf_headers_sz	= kbuf.bufsz;
+	kbuf.memsz		= kbuf.bufsz;
+
+#ifdef CONFIG_CRASH_HOTPLUG
+	/*
+	 * The elfcorehdr segment size accounts for VMCOREINFO, kernel_map,
+	 * maximum CPUs and maximum memory ranges.
+	 */
+	if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG))
+		pnum = 2 + CONFIG_NR_CPUS_DEFAULT + CONFIG_CRASH_MAX_MEMORY_RANGES;
+	else
+		pnum += 2 + CONFIG_NR_CPUS_DEFAULT;
+
+	if (pnum < (unsigned long)PN_XNUM) {
+		kbuf.memsz = pnum * sizeof(Elf64_Phdr);
+		kbuf.memsz += sizeof(Elf64_Ehdr);
+
+		image->elfcorehdr_index = image->nr_segments;
+
+		/* Mark as usable to crash kernel, else crash kernel fails on boot */
+		image->elf_headers_sz = kbuf.memsz;
+	} else {
+		pr_err("number of Phdrs %lu exceeds max\n", pnum);
+	}
+#endif
+
+	kbuf.buf_align = ELF_CORE_HEADER_ALIGN;
+	kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
+	ret = kexec_add_buffer(&kbuf);
+	if (ret)
+		return ret;
+	image->elf_load_addr = kbuf.mem;
+	pr_debug("Loaded ELF headers at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
+		 image->elf_load_addr, kbuf.bufsz, kbuf.memsz);
+
+	return ret;
+}
+#endif /* CONFIG_KEXEC_FILE */
+
+#ifdef CONFIG_CRASH_HOTPLUG
+
+#undef pr_fmt
+#define pr_fmt(fmt) "crash hp: " fmt
+
+/* These functions provide the value for the sysfs crash_hotplug nodes */
+#ifdef CONFIG_HOTPLUG_CPU
+int arch_crash_hotplug_cpu_support(void)
+{
+	return crash_check_update_elfcorehdr();
+}
+#endif
+
+#ifdef CONFIG_MEMORY_HOTPLUG
+int arch_crash_hotplug_memory_support(void)
+{
+	return crash_check_update_elfcorehdr();
+}
+#endif
+
+unsigned int arch_crash_get_elfcorehdr_size(void)
+{
+	unsigned int sz;
+
+	/* kernel_map, VMCOREINFO and maximum CPUs */
+	sz = 2 + CONFIG_NR_CPUS_DEFAULT;
+	if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG))
+		sz += CONFIG_CRASH_MAX_MEMORY_RANGES;
+	sz *= sizeof(Elf64_Phdr);
+	return sz;
+}
+
+/**
+ * arch_crash_handle_hotplug_event() - Handle hotplug elfcorehdr changes
+ * @image: a pointer to kexec_crash_image
+ *
+ * Prepare the new elfcorehdr and replace the existing elfcorehdr.
+ */
+void arch_crash_handle_hotplug_event(struct kimage *image)
+{
+	void *elfbuf = NULL, *old_elfcorehdr;
+	unsigned long nr_mem_ranges;
+	unsigned long mem, memsz;
+	unsigned long elfsz = 0;
+
+	/*
+	 * As crash_prepare_elf64_headers() has already described all
+	 * possible CPUs, there is no need to update the elfcorehdr
+	 * for additional CPU changes.
+	 */
+	if ((image->file_mode || image->elfcorehdr_updated) &&
+		((image->hp_action == KEXEC_CRASH_HP_ADD_CPU) ||
+		(image->hp_action == KEXEC_CRASH_HP_REMOVE_CPU)))
+		return;
+
+	/*
+	 * Create the new elfcorehdr reflecting the changes to CPU and/or
+	 * memory resources.
+	 */
+	if (prepare_elf_headers(image, &elfbuf, &elfsz, &nr_mem_ranges)) {
+		pr_err("unable to create new elfcorehdr");
+		goto out;
+	}
+
+	/*
+	 * Obtain address and size of the elfcorehdr segment, and
+	 * check it against the new elfcorehdr buffer.
+	 */
+	mem = image->segment[image->elfcorehdr_index].mem;
+	memsz = image->segment[image->elfcorehdr_index].memsz;
+	if (elfsz > memsz) {
+		pr_err("update elfcorehdr elfsz %lu > memsz %lu",
+			elfsz, memsz);
+		goto out;
+	}
+
+	/*
+	 * Copy new elfcorehdr over the old elfcorehdr at destination.
+	 */
+	old_elfcorehdr = kmap_local_page(pfn_to_page(mem >> PAGE_SHIFT));
+	if (!old_elfcorehdr) {
+		pr_err("mapping elfcorehdr segment failed\n");
+		goto out;
+	}
+
+	/*
+	 * Temporarily invalidate the crash image while the
+	 * elfcorehdr is updated.
+	 */
+	xchg(&kexec_crash_image, NULL);
+	memcpy_flushcache(old_elfcorehdr, elfbuf, elfsz);
+	xchg(&kexec_crash_image, image);
+	kunmap_local(old_elfcorehdr);
+	pr_debug("updated elfcorehdr\n");
+
+out:
+	vfree(elfbuf);
+}
+#endif