[PATCH 6/6] kexec: Support for Kexec on panic using new system call

From: Vivek Goyal
Date: Wed Nov 20 2013 - 12:52:59 EST

This patch adds support for loading a kexec on panic (kdump) kernel usning
new system call.

Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
---
arch/x86/include/asm/crash.h | 9 +
arch/x86/include/asm/kexec.h | 17 +
arch/x86/kernel/crash.c | 585 ++++++++++++++++++++++++++++++++++++
arch/x86/kernel/kexec-bzimage.c | 63 ++++-
arch/x86/kernel/machine_kexec_64.c | 1 +
kernel/kexec.c | 69 ++++-
6 files changed, 731 insertions(+), 13 deletions(-)
create mode 100644 arch/x86/include/asm/crash.h

diff --git a/arch/x86/include/asm/crash.h b/arch/x86/include/asm/crash.h
new file mode 100644
index 0000000..2dd2eb8
--- /dev/null
+++ b/arch/x86/include/asm/crash.h
@@ -0,0 +1,9 @@
+#ifndef _ASM_X86_CRASH_H
+#define _ASM_X86_CRASH_H
+
+int load_crashdump_segments(struct kimage *image);
+int crash_copy_backup_region(struct kimage *image);
+int crash_setup_memmap_entries(struct kimage *image,
+ struct boot_params *params);
+
+#endif /* _ASM_X86_CRASH_H */
diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 94f1257..9dc19fe 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -64,6 +64,10 @@
# define KEXEC_ARCH KEXEC_ARCH_X86_64
#endif

+/* Memory to backup during crash kdump */
+#define KEXEC_BACKUP_SRC_START (0UL)
+#define KEXEC_BACKUP_SRC_END (655360UL) /* 640K */
+
/*
* CPU does not save ss and sp on stack if execution is already
* running in kernel mode at the time of NMI occurrence. This code
@@ -166,8 +170,21 @@ struct kimage_arch {
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
+ /* Details of backup region */
+ unsigned long backup_src_start;
+ unsigned long backup_src_sz;
+
+ /* Physical address of backup segment */
+ unsigned long backup_load_addr;
+
+ /* Core ELF header buffer */
+ unsigned long elf_headers;
+ unsigned long elf_headers_sz;
+ unsigned long elf_load_addr;
};
+#endif /* CONFIG_X86_32 */

+#ifdef CONFIG_X86_64
struct kexec_entry64_regs {
uint64_t rax;
uint64_t rbx;
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index 18677a9..d5d3118 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -4,6 +4,9 @@
* Created by: Hariprasad Nellitheertha (hari@xxxxxxxxxx)
*
* Copyright (C) IBM Corporation, 2004. All rights reserved.
+ * Copyright (C) Red Hat Inc., 2013. All rights reserved.
+ * Authors:
+ * Vivek Goyal <vgoyal@xxxxxxxxxx>
*
*/

@@ -17,6 +20,7 @@
#include <linux/elf.h>
#include <linux/elfcore.h>
#include <linux/module.h>
+#include <linux/slab.h>

#include <asm/processor.h>
#include <asm/hardirq.h>
@@ -29,6 +33,45 @@
#include <asm/reboot.h>
#include <asm/virtext.h>

+/* Alignment required for elf header segment */
+#define ELF_CORE_HEADER_ALIGN 4096
+
+/* This primarily reprsents number of split ranges due to exclusion */
+#define CRASH_MAX_RANGES 16
+
+struct crash_mem_range {
+ unsigned long long 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 ajustments 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 prepareing memory map entries for second kernel */
+struct crash_memmap_data {
+ struct boot_params *params;
+ /* Type of memory */
+ unsigned int type;
+};
+
int in_crash_kexec;

/*
@@ -138,3 +181,545 @@ void native_machine_crash_shutdown(struct pt_regs *regs)
#endif
crash_save_cpu(regs, safe_smp_processor_id());
}
+
+#ifdef CONFIG_X86_64
+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 int fill_up_ced(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_ram_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 there, another range split possible */
+ if (crashk_low_res.end != 0)
+ ced->max_nr_ranges++;
+
+ return 0;
+}
+
+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 in array */
+ if (!temp_range.end)
+ return 0;
+
+ /* Split happened */
+ if (i == CRASH_MAX_RANGES - 1) {
+ printk("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 place */
+ 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,
+ unsigned long *addr, unsigned long *sz)
+{
+ Elf64_Ehdr *ehdr;
+ Elf64_Phdr *phdr;
+ unsigned long nr_cpus = NR_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_entry = 0;
+ ehdr->e_phoff = sizeof(Elf64_Ehdr);
+ ehdr->e_shoff = 0;
+ ehdr->e_flags = 0;
+ ehdr->e_ehsize = sizeof(Elf64_Ehdr);
+ ehdr->e_phentsize = sizeof(Elf64_Phdr);
+ ehdr->e_phnum = 0;
+ ehdr->e_shentsize = 0;
+ ehdr->e_shnum = 0;
+ ehdr->e_shstrndx = 0;
+
+ /* 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;
+ phdr->p_flags = 0;
+ notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
+ phdr->p_offset = phdr->p_paddr = notes_addr;
+ phdr->p_vaddr = 0;
+ phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
+ phdr->p_align = 0;
+ (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_flags = 0;
+ phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
+ phdr->p_vaddr = 0;
+ phdr->p_filesz = phdr->p_memsz = sizeof(vmcoreinfo_note);
+ phdr->p_align = 0;
+ (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);
+ phdr->p_align = 0;
+ (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 = (unsigned long)buf;
+ *sz = elf_sz;
+ return 0;
+}
+
+/* Prepare elf headers. Return addr and size */
+static int prepare_elf_headers(struct kimage *image, unsigned long *addr,
+ unsigned long *sz)
+{
+ struct crash_elf_data *ced;
+ int ret;
+
+ ced = kzalloc(sizeof(*ced), GFP_KERNEL);
+ if (!ced)
+ return -ENOMEM;
+
+ ret = fill_up_ced(ced, image);
+ if (ret)
+ goto out;
+
+ /* By default prepare 64bit headers */
+ ret = prepare_elf64_headers(ced, addr, sz);
+out:
+ 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++;
+
+ pr_debug("Add e820 entry to bootparams. addr=0x%llx size=0x%llx"
+ " type=%d\n", entry->addr, entry->size, entry->type);
+ 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;
+
+ memset(cmem->ranges, 0, sizeof(cmem->ranges));
+
+ 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;
+ ret = exclude_mem_range(cmem, start, end);
+ return ret;
+}
+
+/* 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_ram_res("ACPI Tables", flags, 0, -1, &cmd, memmap_entry_callback);
+
+ /* Add ACPI Non-volatile Storage */
+ cmd.type = E820_NVS;
+ walk_ram_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.addr = cmem->ranges[i].start;
+ ei.size = cmem->ranges[i].end - ei.addr + 1;
+ ei.type = E820_RAM;
+
+ /* If entry is less than a page, skip it */
+ if (ei.size < PAGE_SIZE) {
+ continue;
+ }
+ 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 load_crashdump_segments(struct kimage *image)
+{
+ unsigned long src_start, src_sz;
+ unsigned long elf_addr, elf_sz;
+ 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 of 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) {
+ ret = kexec_add_buffer(image, __va(src_start), src_sz, src_sz,
+ PAGE_SIZE, 0, -1, 0,
+ &image->arch.backup_load_addr);
+ if (ret)
+ return ret;
+ }
+
+ /* 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)
+ kfree((void *)image->arch.elf_headers);
+
+ return ret;
+}
+
+int crash_copy_backup_region(struct kimage *image)
+{
+ unsigned long dest_start, src_start, src_sz;
+
+ dest_start = image->arch.backup_load_addr;
+ src_start = image->arch.backup_src_start;
+ src_sz = image->arch.backup_src_sz;
+
+ memcpy(__va(dest_start), __va(src_start), src_sz);
+
+ return 0;
+}
+#endif /* CONFIG_X86_64 */
diff --git a/arch/x86/kernel/kexec-bzimage.c b/arch/x86/kernel/kexec-bzimage.c
index a1032d4..606942c 100644
--- a/arch/x86/kernel/kexec-bzimage.c
+++ b/arch/x86/kernel/kexec-bzimage.c
@@ -8,6 +8,9 @@

#include <asm/bootparam.h>
#include <asm/setup.h>
+#include <asm/crash.h>
+
+#define MAX_ELFCOREHDR_STR_LEN 30 /* elfcorehdr=0x<64bit-value> */

#ifdef CONFIG_X86_64

@@ -86,7 +89,8 @@ static int setup_memory_map_entries(struct boot_params *params)
return 0;
}

-static void setup_linux_system_parameters(struct boot_params *params)
+static void setup_linux_system_parameters(struct kimage *image,
+ struct boot_params *params)
{
unsigned int nr_e820_entries;
unsigned long long mem_k, start, end;
@@ -113,7 +117,10 @@ static void setup_linux_system_parameters(struct boot_params *params)
/* Default sysdesc table */
params->sys_desc_table.length = 0;

- setup_memory_map_entries(params);
+ if (image->type == KEXEC_TYPE_CRASH)
+ crash_setup_memmap_entries(image, params);
+ else
+ setup_memory_map_entries(params);
nr_e820_entries = params->e820_entries;

for(i = 0; i < nr_e820_entries; i++) {
@@ -151,18 +158,23 @@ static void setup_initrd(struct boot_params *boot_params, unsigned long initrd_l
boot_params->ext_ramdisk_size = initrd_len >> 32;
}

-static void setup_cmdline(struct boot_params *boot_params,
+static void setup_cmdline(struct kimage *image, struct boot_params *boot_params,
unsigned long bootparams_load_addr,
unsigned long cmdline_offset, char *cmdline,
unsigned long cmdline_len)
{
char *cmdline_ptr = ((char *)boot_params) + cmdline_offset;
- unsigned long cmdline_ptr_phys;
+ unsigned long cmdline_ptr_phys, len;
uint32_t cmdline_low_32, cmdline_ext_32;

memcpy(cmdline_ptr, cmdline, cmdline_len);
+ if (image->type == KEXEC_TYPE_CRASH) {
+ len = sprintf(cmdline_ptr + cmdline_len - 1,
+ " elfcorehdr=0x%lx", image->arch.elf_load_addr);
+ cmdline_len += len;
+ }
cmdline_ptr[cmdline_len - 1] = '\0';
-
+ pr_debug("Final command line is:%s\n", cmdline_ptr);
cmdline_ptr_phys = bootparams_load_addr + cmdline_offset;
cmdline_low_32 = cmdline_ptr_phys & 0xffffffffUL;
cmdline_ext_32 = cmdline_ptr_phys >> 32;
@@ -203,17 +215,34 @@ void *bzImage64_load(struct kimage *image, char *kernel,
return ERR_PTR(-EINVAL);
}

+ /*
+ * In case of crash dump, we will append elfcorehdr=<addr> to
+ * command line. Make sure it does not overflow
+ */
+ if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
+ ret = -EINVAL;
+ pr_debug("Kernel command line too long\n");
+ return ERR_PTR(-EINVAL);
+ }
+
/* Allocate loader specific data */
ldata = kzalloc(sizeof(struct bzimage64_data), GFP_KERNEL);
if (!ldata)
return ERR_PTR(-ENOMEM);

+ /* Allocate and load backup region */
+ if (image->type == KEXEC_TYPE_CRASH) {
+ ret = load_crashdump_segments(image);
+ if (ret)
+ goto out_free_loader_data;
+ }
+
/* Argument/parameter segment */
kern16_size_needed = kern16_size;
if (kern16_size_needed < 4096)
kern16_size_needed = 4096;

- setup_size = kern16_size_needed + cmdline_len;
+ setup_size = kern16_size_needed + cmdline_len + MAX_ELFCOREHDR_STR_LEN;
params = kzalloc(setup_size, GFP_KERNEL);
if (!params) {
ret = -ENOMEM;
@@ -259,14 +288,14 @@ void *bzImage64_load(struct kimage *image, char *kernel,
setup_initrd(params, initrd_load_addr, initrd_len);
}

- setup_cmdline(params, bootparam_load_addr, kern16_size_needed,
+ setup_cmdline(image, params, bootparam_load_addr, kern16_size_needed,
cmdline, cmdline_len);

/* bootloader info. Do we need a separate ID for kexec kernel loader? */
params->hdr.type_of_loader = 0x0D << 4;
params->hdr.loadflags = 0;

- setup_linux_system_parameters(params);
+ setup_linux_system_parameters(image, params);

/*
* Allocate a purgatory page. For 64bit entry point, purgatory
@@ -302,7 +331,7 @@ out_free_loader_data:
return ERR_PTR(ret);
}

-int bzImage64_prep_entry(struct kimage *image)
+static int prepare_purgatory(struct kimage *image)
{
struct bzimage64_data *ldata;
char *purgatory_page;
@@ -362,6 +391,22 @@ int bzImage64_prep_entry(struct kimage *image)
return 0;
}

+int bzImage64_prep_entry(struct kimage *image)
+{
+ if (!image->file_mode)
+ return 0;
+
+ if (!image->image_loader_data)
+ return -EINVAL;
+
+ prepare_purgatory(image);
+
+ if (image->type == KEXEC_TYPE_CRASH)
+ crash_copy_backup_region(image);
+
+ return 0;
+}
+
/* This cleanup function is called after various segments have been loaded */
int bzImage64_cleanup(struct kimage *image)
{
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index a66ce1d..9d7a42d 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -334,6 +334,7 @@ int arch_image_file_post_load_cleanup(struct kimage *image)
{
int idx = image->file_handler_idx;

+ vfree((void *)image->arch.elf_headers);
if (kexec_file_type[idx].cleanup)
return kexec_file_type[idx].cleanup(image);
return 0;
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 50bcaa8..64184a7 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -524,7 +524,6 @@ static int kimage_normal_alloc(struct kimage **rimage, unsigned long entry,
*rimage = image;
return 0;

-
out_free_control_pages:
kimage_free_page_list(&image->control_pages);
out_free_image:
@@ -532,6 +531,54 @@ out_free_image:
return result;
}

+static int kimage_file_crash_alloc(struct kimage **rimage, int kernel_fd,
+ int initrd_fd, const char __user *cmdline_ptr,
+ unsigned long cmdline_len)
+{
+ int result;
+ struct kimage *image;
+
+ /* Allocate and initialize a controlling structure */
+ image = do_kimage_alloc_init();
+ if (!image)
+ return -ENOMEM;
+
+ image->file_mode = 1;
+ image->file_handler_idx = -1;
+
+ /* Enable the special crash kernel control page allocation policy. */
+ image->control_page = crashk_res.start;
+ image->type = KEXEC_TYPE_CRASH;
+
+ result = kimage_file_prepare_segments(image, kernel_fd, initrd_fd,
+ cmdline_ptr, cmdline_len);
+ if (result)
+ goto out_free_image;
+
+ result = sanity_check_segment_list(image);
+ if (result)
+ goto out_free_post_load_bufs;
+
+ result = -ENOMEM;
+ image->control_code_page = kimage_alloc_control_pages(image,
+ get_order(KEXEC_CONTROL_PAGE_SIZE));
+ if (!image->control_code_page) {
+ printk(KERN_ERR "Could not allocate control_code_buffer\n");
+ goto out_free_post_load_bufs;
+ }
+
+ *rimage = image;
+ return 0;
+
+out_free_post_load_bufs:
+ kimage_file_post_load_cleanup(image);
+ kfree(image->image_loader_data);
+out_free_image:
+ kfree(image);
+ return result;
+}
+
+
static int kimage_crash_alloc(struct kimage **rimage, unsigned long entry,
unsigned long nr_segments,
struct kexec_segment __user *segments)
@@ -1130,7 +1177,12 @@ static int kimage_load_crash_segment(struct kimage *image,
/* Zero the trailing part of the page */
memset(ptr + uchunk, 0, mchunk - uchunk);
}
- result = copy_from_user(ptr, buf, uchunk);
+
+ /* For file based kexec, source pages are in kernel memory */
+ if (image->file_mode)
+ memcpy(ptr, buf, uchunk);
+ else
+ result = copy_from_user(ptr, buf, uchunk);
kexec_flush_icache_page(page);
kunmap(page);
if (result) {
@@ -1358,7 +1410,11 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, const char __us
if (flags & KEXEC_FILE_UNLOAD)
goto exchange;

- ret = kimage_file_normal_alloc(&image, kernel_fd, initrd_fd,
+ if (flags & KEXEC_FILE_ON_CRASH)
+ ret = kimage_file_crash_alloc(&image, kernel_fd, initrd_fd,
+ cmdline_ptr, cmdline_len);
+ else
+ ret = kimage_file_normal_alloc(&image, kernel_fd, initrd_fd,
cmdline_ptr, cmdline_len);
if (ret)
goto out;
@@ -2108,7 +2164,12 @@ int kexec_add_buffer(struct kimage *image, char *buffer,
kbuf->top_down = top_down;

/* Walk the RAM ranges and allocate a suitable range for the buffer */
- walk_system_ram_res(0, -1, kbuf, walk_ram_range_callback);
+ if (image->type == KEXEC_TYPE_CRASH)
+ walk_ram_res("Crash kernel", IORESOURCE_MEM | IORESOURCE_BUSY,
+ crashk_res.start, crashk_res.end, kbuf,
+ walk_ram_range_callback);
+ else
+ walk_system_ram_res(0, -1, kbuf, walk_ram_range_callback);

kbuf->image = NULL;
kfree(kbuf);
--
1.7.7.6

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