1 files changed, 561 insertions, 0 deletions

diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index 507de8066594..a618fcd2c07d 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -4,9 +4,14 @@
  * 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>
@@ -16,6 +21,7 @@
 #include <linux/elf.h>
 #include <linux/elfcore.h>
 #include <linux/module.h>
+#include <linux/slab.h>
 
 #include <asm/processor.h>
 #include <asm/hardirq.h>
@@ -28,6 +34,45 @@
 #include <asm/reboot.h>
 #include <asm/virtext.h>
 
+/* Alignment required for elf header segment */
+#define ELF_CORE_HEADER_ALIGN   4096
+
+/* This primarily represents number of split ranges due to exclusion */
+#define CRASH_MAX_RANGES	16
+
+struct crash_mem_range {
+	u64 start, end;
+};
+
+struct crash_mem {
+	unsigned int nr_ranges;
+	struct crash_mem_range ranges[CRASH_MAX_RANGES];
+};
+
+/* Misc data about ram ranges needed to prepare elf headers */
+struct crash_elf_data {
+	struct kimage *image;
+	/*
+	 * Total number of ram ranges we have after various adjustments for
+	 * GART, crash reserved region etc.
+	 */
+	unsigned int max_nr_ranges;
+	unsigned long gart_start, gart_end;
+
+	/* Pointer to elf header */
+	void *ehdr;
+	/* Pointer to next phdr */
+	void *bufp;
+	struct crash_mem mem;
+};
+
+/* Used while preparing memory map entries for second kernel */
+struct crash_memmap_data {
+	struct boot_params *params;
+	/* Type of memory */
+	unsigned int type;
+};
+
 int in_crash_kexec;
 
 /*
@@ -39,6 +84,7 @@ int in_crash_kexec;
  */
 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)
 {
@@ -135,3 +181,518 @@ void native_machine_crash_shutdown(struct pt_regs *regs)
 #endif
 	crash_save_cpu(regs, safe_smp_processor_id());
 }
+
+#ifdef CONFIG_KEXEC_FILE
+static int get_nr_ram_ranges_callback(unsigned long start_pfn,
+				unsigned long nr_pfn, void *arg)
+{
+	int *nr_ranges = arg;
+
+	(*nr_ranges)++;
+	return 0;
+}
+
+static int get_gart_ranges_callback(u64 start, u64 end, void *arg)
+{
+	struct crash_elf_data *ced = arg;
+
+	ced->gart_start = start;
+	ced->gart_end = end;
+
+	/* Not expecting more than 1 gart aperture */
+	return 1;
+}
+
+
+/* Gather all the required information to prepare elf headers for ram regions */
+static void fill_up_crash_elf_data(struct crash_elf_data *ced,
+				   struct kimage *image)
+{
+	unsigned int nr_ranges = 0;
+
+	ced->image = image;
+
+	walk_system_ram_range(0, -1, &nr_ranges,
+				get_nr_ram_ranges_callback);
+
+	ced->max_nr_ranges = nr_ranges;
+
+	/*
+	 * We don't create ELF headers for GART aperture as an attempt
+	 * to dump this memory in second kernel leads to hang/crash.
+	 * If gart aperture is present, one needs to exclude that region
+	 * and that could lead to need of extra phdr.
+	 */
+	walk_iomem_res("GART", IORESOURCE_MEM, 0, -1,
+				ced, get_gart_ranges_callback);
+
+	/*
+	 * If we have gart region, excluding that could potentially split
+	 * a memory range, resulting in extra header. Account for  that.
+	 */
+	if (ced->gart_end)
+		ced->max_nr_ranges++;
+
+	/* Exclusion of crash region could split memory ranges */
+	ced->max_nr_ranges++;
+
+	/* If crashk_low_res is not 0, another range split possible */
+	if (crashk_low_res.end != 0)
+		ced->max_nr_ranges++;
+}
+
+static int exclude_mem_range(struct crash_mem *mem,
+		unsigned long long mstart, unsigned long long mend)
+{
+	int i, j;
+	unsigned long long start, end;
+	struct crash_mem_range temp_range = {0, 0};
+
+	for (i = 0; i < mem->nr_ranges; i++) {
+		start = mem->ranges[i].start;
+		end = mem->ranges[i].end;
+
+		if (mstart > end || mend < start)
+			continue;
+
+		/* Truncate any area outside of range */
+		if (mstart < start)
+			mstart = start;
+		if (mend > end)
+			mend = end;
+
+		/* Found completely overlapping range */
+		if (mstart == start && mend == end) {
+			mem->ranges[i].start = 0;
+			mem->ranges[i].end = 0;
+			if (i < mem->nr_ranges - 1) {
+				/* Shift rest of the ranges to left */
+				for (j = i; j < mem->nr_ranges - 1; j++) {
+					mem->ranges[j].start =
+						mem->ranges[j+1].start;
+					mem->ranges[j].end =
+							mem->ranges[j+1].end;
+				}
+			}
+			mem->nr_ranges--;
+			return 0;
+		}
+
+		if (mstart > start && mend < end) {
+			/* Split original range */
+			mem->ranges[i].end = mstart - 1;
+			temp_range.start = mend + 1;
+			temp_range.end = end;
+		} else if (mstart != start)
+			mem->ranges[i].end = mstart - 1;
+		else
+			mem->ranges[i].start = mend + 1;
+		break;
+	}
+
+	/* If a split happend, add the split to array */
+	if (!temp_range.end)
+		return 0;
+
+	/* Split happened */
+	if (i == CRASH_MAX_RANGES - 1) {
+		pr_err("Too many crash ranges after split\n");
+		return -ENOMEM;
+	}
+
+	/* Location where new range should go */
+	j = i + 1;
+	if (j < mem->nr_ranges) {
+		/* Move over all ranges one slot towards the end */
+		for (i = mem->nr_ranges - 1; i >= j; i--)
+			mem->ranges[i + 1] = mem->ranges[i];
+	}
+
+	mem->ranges[j].start = temp_range.start;
+	mem->ranges[j].end = temp_range.end;
+	mem->nr_ranges++;
+	return 0;
+}
+
+/*
+ * Look for any unwanted ranges between mstart, mend and remove them. This
+ * might lead to split and split ranges are put in ced->mem.ranges[] array
+ */
+static int elf_header_exclude_ranges(struct crash_elf_data *ced,
+		unsigned long long mstart, unsigned long long mend)
+{
+	struct crash_mem *cmem = &ced->mem;
+	int ret = 0;
+
+	memset(cmem->ranges, 0, sizeof(cmem->ranges));
+
+	cmem->ranges[0].start = mstart;
+	cmem->ranges[0].end = mend;
+	cmem->nr_ranges = 1;
+
+	/* Exclude crashkernel region */
+	ret = exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
+	if (ret)
+		return ret;
+
+	ret = exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
+	if (ret)
+		return ret;
+
+	/* Exclude GART region */
+	if (ced->gart_end) {
+		ret = exclude_mem_range(cmem, ced->gart_start, ced->gart_end);
+		if (ret)
+			return ret;
+	}
+
+	return ret;
+}
+
+static int prepare_elf64_ram_headers_callback(u64 start, u64 end, void *arg)
+{
+	struct crash_elf_data *ced = arg;
+	Elf64_Ehdr *ehdr;
+	Elf64_Phdr *phdr;
+	unsigned long mstart, mend;
+	struct kimage *image = ced->image;
+	struct crash_mem *cmem;
+	int ret, i;
+
+	ehdr = ced->ehdr;
+
+	/* Exclude unwanted mem ranges */
+	ret = elf_header_exclude_ranges(ced, start, end);
+	if (ret)
+		return ret;
+
+	/* Go through all the ranges in ced->mem.ranges[] and prepare phdr */
+	cmem = &ced->mem;
+
+	for (i = 0; i < cmem->nr_ranges; i++) {
+		mstart = cmem->ranges[i].start;
+		mend = cmem->ranges[i].end;
+
+		phdr = ced->bufp;
+		ced->bufp += sizeof(Elf64_Phdr);
+
+		phdr->p_type = PT_LOAD;
+		phdr->p_flags = PF_R|PF_W|PF_X;
+		phdr->p_offset  = mstart;
+
+		/*
+		 * If a range matches backup region, adjust offset to backup
+		 * segment.
+		 */
+		if (mstart == image->arch.backup_src_start &&
+		    (mend - mstart + 1) == image->arch.backup_src_sz)
+			phdr->p_offset = image->arch.backup_load_addr;
+
+		phdr->p_paddr = mstart;
+		phdr->p_vaddr = (unsigned long long) __va(mstart);
+		phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
+		phdr->p_align = 0;
+		ehdr->e_phnum++;
+		pr_debug("Crash PT_LOAD elf header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n",
+			phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
+			ehdr->e_phnum, phdr->p_offset);
+	}
+
+	return ret;
+}
+
+static int prepare_elf64_headers(struct crash_elf_data *ced,
+		void **addr, unsigned long *sz)
+{
+	Elf64_Ehdr *ehdr;
+	Elf64_Phdr *phdr;
+	unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
+	unsigned char *buf, *bufp;
+	unsigned int cpu;
+	unsigned long long notes_addr;
+	int ret;
+
+	/* extra phdr for vmcoreinfo elf note */
+	nr_phdr = nr_cpus + 1;
+	nr_phdr += ced->max_nr_ranges;
+
+	/*
+	 * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
+	 * area on x86_64 (ffffffff80000000 - ffffffffa0000000).
+	 * I think this is required by tools like gdb. So same physical
+	 * memory will be mapped in two elf headers. One will contain kernel
+	 * text virtual addresses and other will have __va(physical) addresses.
+	 */
+
+	nr_phdr++;
+	elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
+	elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
+
+	buf = vzalloc(elf_sz);
+	if (!buf)
+		return -ENOMEM;
+
+	bufp = buf;
+	ehdr = (Elf64_Ehdr *)bufp;
+	bufp += sizeof(Elf64_Ehdr);
+	memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
+	ehdr->e_ident[EI_CLASS] = ELFCLASS64;
+	ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
+	ehdr->e_ident[EI_VERSION] = EV_CURRENT;
+	ehdr->e_ident[EI_OSABI] = ELF_OSABI;
+	memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
+	ehdr->e_type = ET_CORE;
+	ehdr->e_machine = ELF_ARCH;
+	ehdr->e_version = EV_CURRENT;
+	ehdr->e_phoff = sizeof(Elf64_Ehdr);
+	ehdr->e_ehsize = sizeof(Elf64_Ehdr);
+	ehdr->e_phentsize = sizeof(Elf64_Phdr);
+
+	/* Prepare one phdr of type PT_NOTE for each present cpu */
+	for_each_present_cpu(cpu) {
+		phdr = (Elf64_Phdr *)bufp;
+		bufp += sizeof(Elf64_Phdr);
+		phdr->p_type = PT_NOTE;
+		notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
+		phdr->p_offset = phdr->p_paddr = notes_addr;
+		phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
+		(ehdr->e_phnum)++;
+	}
+
+	/* Prepare one PT_NOTE header for vmcoreinfo */
+	phdr = (Elf64_Phdr *)bufp;
+	bufp += sizeof(Elf64_Phdr);
+	phdr->p_type = PT_NOTE;
+	phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
+	phdr->p_filesz = phdr->p_memsz = sizeof(vmcoreinfo_note);
+	(ehdr->e_phnum)++;
+
+#ifdef CONFIG_X86_64
+	/* Prepare PT_LOAD type program header for kernel text region */
+	phdr = (Elf64_Phdr *)bufp;
+	bufp += sizeof(Elf64_Phdr);
+	phdr->p_type = PT_LOAD;
+	phdr->p_flags = PF_R|PF_W|PF_X;
+	phdr->p_vaddr = (Elf64_Addr)_text;
+	phdr->p_filesz = phdr->p_memsz = _end - _text;
+	phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
+	(ehdr->e_phnum)++;
+#endif
+
+	/* Prepare PT_LOAD headers for system ram chunks. */
+	ced->ehdr = ehdr;
+	ced->bufp = bufp;
+	ret = walk_system_ram_res(0, -1, ced,
+			prepare_elf64_ram_headers_callback);
+	if (ret < 0)
+		return ret;
+
+	*addr = buf;
+	*sz = elf_sz;
+	return 0;
+}
+
+/* Prepare elf headers. Return addr and size */
+static int prepare_elf_headers(struct kimage *image, void **addr,
+					unsigned long *sz)
+{
+	struct crash_elf_data *ced;
+	int ret;
+
+	ced = kzalloc(sizeof(*ced), GFP_KERNEL);
+	if (!ced)
+		return -ENOMEM;
+
+	fill_up_crash_elf_data(ced, image);
+
+	/* By default prepare 64bit headers */
+	ret =  prepare_elf64_headers(ced, addr, sz);
+	kfree(ced);
+	return ret;
+}
+
+static int add_e820_entry(struct boot_params *params, struct e820entry *entry)
+{
+	unsigned int nr_e820_entries;
+
+	nr_e820_entries = params->e820_entries;
+	if (nr_e820_entries >= E820MAX)
+		return 1;
+
+	memcpy(&params->e820_map[nr_e820_entries], entry,
+			sizeof(struct e820entry));
+	params->e820_entries++;
+	return 0;
+}
+
+static int memmap_entry_callback(u64 start, u64 end, void *arg)
+{
+	struct crash_memmap_data *cmd = arg;
+	struct boot_params *params = cmd->params;
+	struct e820entry ei;
+
+	ei.addr = start;
+	ei.size = end - start + 1;
+	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 = 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 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 e820entry ei;
+	struct crash_memmap_data cmd;
+	struct crash_mem *cmem;
+
+	cmem = vzalloc(sizeof(struct crash_mem));
+	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_RAM;
+	add_e820_entry(params, &ei);
+
+	/* Add ACPI tables */
+	cmd.type = E820_ACPI;
+	flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+	walk_iomem_res("ACPI Tables", flags, 0, -1, &cmd,
+		       memmap_entry_callback);
+
+	/* Add ACPI Non-volatile Storage */
+	cmd.type = E820_NVS;
+	walk_iomem_res("ACPI Non-volatile 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_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_RAM;
+		add_e820_entry(params, &ei);
+	}
+
+out:
+	vfree(cmem);
+	return ret;
+}
+
+static int determine_backup_region(u64 start, u64 end, void *arg)
+{
+	struct kimage *image = arg;
+
+	image->arch.backup_src_start = start;
+	image->arch.backup_src_sz = end - start + 1;
+
+	/* Expecting only one range for backup region */
+	return 1;
+}
+
+int crash_load_segments(struct kimage *image)
+{
+	unsigned long src_start, src_sz, elf_sz;
+	void *elf_addr;
+	int ret;
+
+	/*
+	 * 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;
+
+	src_start = image->arch.backup_src_start;
+	src_sz = image->arch.backup_src_sz;
+
+	/* Add backup segment. */
+	if (src_sz) {
+		/*
+		 * 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(image, (char *)&crash_zero_bytes,
+				       sizeof(crash_zero_bytes), src_sz,
+				       PAGE_SIZE, 0, -1, 0,
+				       &image->arch.backup_load_addr);
+		if (ret)
+			return ret;
+		pr_debug("Loaded backup region at 0x%lx backup_start=0x%lx memsz=0x%lx\n",
+			 image->arch.backup_load_addr, src_start, src_sz);
+	}
+
+	/* Prepare elf headers and add a segment */
+	ret = prepare_elf_headers(image, &elf_addr, &elf_sz);
+	if (ret)
+		return ret;
+
+	image->arch.elf_headers = elf_addr;
+	image->arch.elf_headers_sz = elf_sz;
+
+	ret = kexec_add_buffer(image, (char *)elf_addr, elf_sz, elf_sz,
+			ELF_CORE_HEADER_ALIGN, 0, -1, 0,
+			&image->arch.elf_load_addr);
+	if (ret) {
+		vfree((void *)image->arch.elf_headers);
+		return ret;
+	}
+	pr_debug("Loaded ELF headers at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
+		 image->arch.elf_load_addr, elf_sz, elf_sz);
+
+	return ret;
+}
+#endif /* CONFIG_KEXEC_FILE */