prepare_elf_headers() can also be useful for other architectures,
including arm64. So let it factored out.

Signed-off-by: AKASHI Takahiro <takahiro.aka...@linaro.org>
Cc: Dave Young <dyo...@redhat.com>
Cc: Vivek Goyal <vgo...@redhat.com>
Cc: Baoquan He <b...@redhat.com>
---
 arch/x86/kernel/crash.c | 324 ------------------------------------------------
 include/linux/kexec.h   |  17 +++
 kernel/kexec_file.c     | 308 +++++++++++++++++++++++++++++++++++++++++++++
 kernel/kexec_internal.h |  20 +++
 4 files changed, 345 insertions(+), 324 deletions(-)

diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index 10e74d4778a1..bb8f3dcddaaa 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -21,7 +21,6 @@
 #include <linux/elf.h>
 #include <linux/elfcore.h>
 #include <linux/export.h>
-#include <linux/slab.h>
 #include <linux/vmalloc.h>
 
 #include <asm/processor.h>
@@ -41,34 +40,6 @@
 /* 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
-        * crash reserved region, etc.
-        */
-       unsigned int max_nr_ranges;
-
-       /* 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;
@@ -209,301 +180,6 @@ void native_machine_crash_shutdown(struct pt_regs *regs)
 }
 
 #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 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_res(0, -1, &nr_ranges,
-                               get_nr_ram_ranges_callback);
-
-       ced->max_nr_ranges = 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)
-               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;
-
-       if (crashk_low_res.end) {
-               ret = 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_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, res->start, res->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 = VMCOREINFO_NOTE_SIZE;
-       (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 e820_entry *entry)
 {
        unsigned int nr_e820_entries;
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 325980537125..a8ac11633969 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -163,6 +163,23 @@ int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf,
                               int (*func)(struct resource *, void *));
 extern int kexec_add_buffer(struct kexec_buf *kbuf);
 int kexec_locate_mem_hole(struct kexec_buf *kbuf);
+extern int prepare_elf_headers(struct kimage *image, void **addr,
+                               unsigned long *sz);
+
+/* 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];
+};
+
+extern int exclude_mem_range(struct crash_mem *mem,
+               unsigned long long mstart, unsigned long long mend);
 #endif /* CONFIG_KEXEC_FILE */
 
 struct kimage {
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index c95e3ffd4be8..b2c425e6afc6 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -22,6 +22,11 @@
 #include <linux/ima.h>
 #include <crypto/hash.h>
 #include <crypto/sha.h>
+#include <linux/elf.h>
+#include <linux/elfcore.h>
+#include <linux/kernel.h>
+#include <linux/kexec.h>
+#include <linux/slab.h>
 #include <linux/syscalls.h>
 #include <linux/vmalloc.h>
 #include "kexec_internal.h"
@@ -1071,3 +1076,306 @@ int kexec_purgatory_get_set_symbol(struct kimage 
*image, const char *name,
 
        return 0;
 }
+
+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 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_res(0, -1, &nr_ranges,
+                               get_nr_ram_ranges_callback);
+
+       ced->max_nr_ranges = nr_ranges;
+
+       /* Exclusion of crash region could split memory ranges */
+       ced->max_nr_ranges++;
+
+#ifdef CONFIG_X86_64
+       /* If crashk_low_res is not 0, another range split possible */
+       if (crashk_low_res.end)
+               ced->max_nr_ranges++;
+#endif
+}
+
+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 happened, 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;
+
+#ifdef CONFIG_X86_64
+       if (crashk_low_res.end) {
+               ret = exclude_mem_range(cmem, crashk_low_res.start,
+                                               crashk_low_res.end);
+               if (ret)
+                       return ret;
+       }
+#endif
+
+       return ret;
+}
+
+static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
+{
+       struct crash_elf_data *ced = arg;
+       Elf64_Ehdr *ehdr;
+       Elf64_Phdr *phdr;
+       unsigned long mstart, mend;
+#ifdef CONFIG_X86_64
+       struct kimage *image = ced->image;
+#endif
+       struct crash_mem *cmem;
+       int ret, i;
+
+       ehdr = ced->ehdr;
+
+       /* Exclude unwanted mem ranges */
+       ret = elf_header_exclude_ranges(ced, res->start, res->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;
+
+#ifdef CONFIG_X86_64
+               /*
+                * 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;
+#endif
+
+               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 = VMCOREINFO_NOTE_SIZE;
+       (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 */
+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;
+}
diff --git a/kernel/kexec_internal.h b/kernel/kexec_internal.h
index 48aaf2ac0d0d..2415e1f5e558 100644
--- a/kernel/kexec_internal.h
+++ b/kernel/kexec_internal.h
@@ -17,6 +17,26 @@ extern struct mutex kexec_mutex;
 
 #ifdef CONFIG_KEXEC_FILE
 #include <linux/purgatory.h>
+
+/* Alignment required for elf header segment */
+#define ELF_CORE_HEADER_ALIGN   4096
+
+/* 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
+        * crash reserved region, etc.
+        */
+       unsigned int max_nr_ranges;
+
+       /* Pointer to elf header */
+       void *ehdr;
+       /* Pointer to next phdr */
+       void *bufp;
+       struct crash_mem mem;
+};
+
 void kimage_file_post_load_cleanup(struct kimage *image);
 extern char kexec_purgatory[];
 extern size_t kexec_purgatory_size;
-- 
2.14.1


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