Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2440 insertions, 0 deletions

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
new file mode 100644
index 000000000..c41c568ad
--- /dev/null
+++ b/fs/binfmt_elf.c
@@ -0,0 +1,2440 @@
+/*
+ * linux/fs/binfmt_elf.c
+ *
+ * These are the functions used to load ELF format executables as used
+ * on SVr4 machines.  Information on the format may be found in the book
+ * "UNIX SYSTEM V RELEASE 4 Programmers Guide: Ansi C and Programming Support
+ * Tools".
+ *
+ * Copyright 1993, 1994: Eric Youngdale (ericy@cais.com).
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/errno.h>
+#include <linux/signal.h>
+#include <linux/binfmts.h>
+#include <linux/string.h>
+#include <linux/file.h>
+#include <linux/slab.h>
+#include <linux/personality.h>
+#include <linux/elfcore.h>
+#include <linux/init.h>
+#include <linux/highuid.h>
+#include <linux/compiler.h>
+#include <linux/highmem.h>
+#include <linux/pagemap.h>
+#include <linux/vmalloc.h>
+#include <linux/security.h>
+#include <linux/random.h>
+#include <linux/elf.h>
+#include <linux/elf-randomize.h>
+#include <linux/utsname.h>
+#include <linux/coredump.h>
+#include <linux/sched.h>
+#include <linux/sched/coredump.h>
+#include <linux/sched/task_stack.h>
+#include <linux/sched/cputime.h>
+#include <linux/cred.h>
+#include <linux/dax.h>
+#include <linux/uaccess.h>
+#include <asm/param.h>
+#include <asm/page.h>
+
+#ifndef user_long_t
+#define user_long_t long
+#endif
+#ifndef user_siginfo_t
+#define user_siginfo_t siginfo_t
+#endif
+
+/* That's for binfmt_elf_fdpic to deal with */
+#ifndef elf_check_fdpic
+#define elf_check_fdpic(ex) false
+#endif
+
+static int load_elf_binary(struct linux_binprm *bprm);
+static unsigned long elf_map(struct file *, unsigned long, struct elf_phdr *,
+				int, int, unsigned long);
+
+#ifdef CONFIG_USELIB
+static int load_elf_library(struct file *);
+#else
+#define load_elf_library NULL
+#endif
+
+/*
+ * If we don't support core dumping, then supply a NULL so we
+ * don't even try.
+ */
+#ifdef CONFIG_ELF_CORE
+static int elf_core_dump(struct coredump_params *cprm);
+#else
+#define elf_core_dump	NULL
+#endif
+
+#if ELF_EXEC_PAGESIZE > PAGE_SIZE
+#define ELF_MIN_ALIGN	ELF_EXEC_PAGESIZE
+#else
+#define ELF_MIN_ALIGN	PAGE_SIZE
+#endif
+
+#ifndef ELF_CORE_EFLAGS
+#define ELF_CORE_EFLAGS	0
+#endif
+
+#define ELF_PAGESTART(_v) ((_v) & ~(unsigned long)(ELF_MIN_ALIGN-1))
+#define ELF_PAGEOFFSET(_v) ((_v) & (ELF_MIN_ALIGN-1))
+#define ELF_PAGEALIGN(_v) (((_v) + ELF_MIN_ALIGN - 1) & ~(ELF_MIN_ALIGN - 1))
+
+static struct linux_binfmt elf_format = {
+	.module		= THIS_MODULE,
+	.load_binary	= load_elf_binary,
+	.load_shlib	= load_elf_library,
+	.core_dump	= elf_core_dump,
+	.min_coredump	= ELF_EXEC_PAGESIZE,
+};
+
+#define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
+
+static int set_brk(unsigned long start, unsigned long end, int prot)
+{
+	start = ELF_PAGEALIGN(start);
+	end = ELF_PAGEALIGN(end);
+	if (end > start) {
+		/*
+		 * Map the last of the bss segment.
+		 * If the header is requesting these pages to be
+		 * executable, honour that (ppc32 needs this).
+		 */
+		int error = vm_brk_flags(start, end - start,
+				prot & PROT_EXEC ? VM_EXEC : 0);
+		if (error)
+			return error;
+	}
+	current->mm->start_brk = current->mm->brk = end;
+	return 0;
+}
+
+/* We need to explicitly zero any fractional pages
+   after the data section (i.e. bss).  This would
+   contain the junk from the file that should not
+   be in memory
+ */
+static int padzero(unsigned long elf_bss)
+{
+	unsigned long nbyte;
+
+	nbyte = ELF_PAGEOFFSET(elf_bss);
+	if (nbyte) {
+		nbyte = ELF_MIN_ALIGN - nbyte;
+		if (clear_user((void __user *) elf_bss, nbyte))
+			return -EFAULT;
+	}
+	return 0;
+}
+
+/* Let's use some macros to make this stack manipulation a little clearer */
+#ifdef CONFIG_STACK_GROWSUP
+#define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) + (items))
+#define STACK_ROUND(sp, items) \
+	((15 + (unsigned long) ((sp) + (items))) &~ 15UL)
+#define STACK_ALLOC(sp, len) ({ \
+	elf_addr_t __user *old_sp = (elf_addr_t __user *)sp; sp += len; \
+	old_sp; })
+#else
+#define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) - (items))
+#define STACK_ROUND(sp, items) \
+	(((unsigned long) (sp - items)) &~ 15UL)
+#define STACK_ALLOC(sp, len) ({ sp -= len ; sp; })
+#endif
+
+#ifndef ELF_BASE_PLATFORM
+/*
+ * AT_BASE_PLATFORM indicates the "real" hardware/microarchitecture.
+ * If the arch defines ELF_BASE_PLATFORM (in asm/elf.h), the value
+ * will be copied to the user stack in the same manner as AT_PLATFORM.
+ */
+#define ELF_BASE_PLATFORM NULL
+#endif
+
+static int
+create_elf_tables(struct linux_binprm *bprm, struct elfhdr *exec,
+		unsigned long load_addr, unsigned long interp_load_addr)
+{
+	unsigned long p = bprm->p;
+	int argc = bprm->argc;
+	int envc = bprm->envc;
+	elf_addr_t __user *sp;
+	elf_addr_t __user *u_platform;
+	elf_addr_t __user *u_base_platform;
+	elf_addr_t __user *u_rand_bytes;
+	const char *k_platform = ELF_PLATFORM;
+	const char *k_base_platform = ELF_BASE_PLATFORM;
+	unsigned char k_rand_bytes[16];
+	int items;
+	elf_addr_t *elf_info;
+	int ei_index = 0;
+	const struct cred *cred = current_cred();
+	struct vm_area_struct *vma;
+
+	/*
+	 * In some cases (e.g. Hyper-Threading), we want to avoid L1
+	 * evictions by the processes running on the same package. One
+	 * thing we can do is to shuffle the initial stack for them.
+	 */
+
+	p = arch_align_stack(p);
+
+	/*
+	 * If this architecture has a platform capability string, copy it
+	 * to userspace.  In some cases (Sparc), this info is impossible
+	 * for userspace to get any other way, in others (i386) it is
+	 * merely difficult.
+	 */
+	u_platform = NULL;
+	if (k_platform) {
+		size_t len = strlen(k_platform) + 1;
+
+		u_platform = (elf_addr_t __user *)STACK_ALLOC(p, len);
+		if (__copy_to_user(u_platform, k_platform, len))
+			return -EFAULT;
+	}
+
+	/*
+	 * If this architecture has a "base" platform capability
+	 * string, copy it to userspace.
+	 */
+	u_base_platform = NULL;
+	if (k_base_platform) {
+		size_t len = strlen(k_base_platform) + 1;
+
+		u_base_platform = (elf_addr_t __user *)STACK_ALLOC(p, len);
+		if (__copy_to_user(u_base_platform, k_base_platform, len))
+			return -EFAULT;
+	}
+
+	/*
+	 * Generate 16 random bytes for userspace PRNG seeding.
+	 */
+	get_random_bytes(k_rand_bytes, sizeof(k_rand_bytes));
+	u_rand_bytes = (elf_addr_t __user *)
+		       STACK_ALLOC(p, sizeof(k_rand_bytes));
+	if (__copy_to_user(u_rand_bytes, k_rand_bytes, sizeof(k_rand_bytes)))
+		return -EFAULT;
+
+	/* Create the ELF interpreter info */
+	elf_info = (elf_addr_t *)current->mm->saved_auxv;
+	/* update AT_VECTOR_SIZE_BASE if the number of NEW_AUX_ENT() changes */
+#define NEW_AUX_ENT(id, val) \
+	do { \
+		elf_info[ei_index++] = id; \
+		elf_info[ei_index++] = val; \
+	} while (0)
+
+#ifdef ARCH_DLINFO
+	/* 
+	 * ARCH_DLINFO must come first so PPC can do its special alignment of
+	 * AUXV.
+	 * update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT() in
+	 * ARCH_DLINFO changes
+	 */
+	ARCH_DLINFO;
+#endif
+	NEW_AUX_ENT(AT_HWCAP, ELF_HWCAP);
+	NEW_AUX_ENT(AT_PAGESZ, ELF_EXEC_PAGESIZE);
+	NEW_AUX_ENT(AT_CLKTCK, CLOCKS_PER_SEC);
+	NEW_AUX_ENT(AT_PHDR, load_addr + exec->e_phoff);
+	NEW_AUX_ENT(AT_PHENT, sizeof(struct elf_phdr));
+	NEW_AUX_ENT(AT_PHNUM, exec->e_phnum);
+	NEW_AUX_ENT(AT_BASE, interp_load_addr);
+	NEW_AUX_ENT(AT_FLAGS, 0);
+	NEW_AUX_ENT(AT_ENTRY, exec->e_entry);
+	NEW_AUX_ENT(AT_UID, from_kuid_munged(cred->user_ns, cred->uid));
+	NEW_AUX_ENT(AT_EUID, from_kuid_munged(cred->user_ns, cred->euid));
+	NEW_AUX_ENT(AT_GID, from_kgid_munged(cred->user_ns, cred->gid));
+	NEW_AUX_ENT(AT_EGID, from_kgid_munged(cred->user_ns, cred->egid));
+	NEW_AUX_ENT(AT_SECURE, bprm->secureexec);
+	NEW_AUX_ENT(AT_RANDOM, (elf_addr_t)(unsigned long)u_rand_bytes);
+#ifdef ELF_HWCAP2
+	NEW_AUX_ENT(AT_HWCAP2, ELF_HWCAP2);
+#endif
+	NEW_AUX_ENT(AT_EXECFN, bprm->exec);
+	if (k_platform) {
+		NEW_AUX_ENT(AT_PLATFORM,
+			    (elf_addr_t)(unsigned long)u_platform);
+	}
+	if (k_base_platform) {
+		NEW_AUX_ENT(AT_BASE_PLATFORM,
+			    (elf_addr_t)(unsigned long)u_base_platform);
+	}
+	if (bprm->interp_flags & BINPRM_FLAGS_EXECFD) {
+		NEW_AUX_ENT(AT_EXECFD, bprm->interp_data);
+	}
+#undef NEW_AUX_ENT
+	/* AT_NULL is zero; clear the rest too */
+	memset(&elf_info[ei_index], 0,
+	       sizeof current->mm->saved_auxv - ei_index * sizeof elf_info[0]);
+
+	/* And advance past the AT_NULL entry.  */
+	ei_index += 2;
+
+	sp = STACK_ADD(p, ei_index);
+
+	items = (argc + 1) + (envc + 1) + 1;
+	bprm->p = STACK_ROUND(sp, items);
+
+	/* Point sp at the lowest address on the stack */
+#ifdef CONFIG_STACK_GROWSUP
+	sp = (elf_addr_t __user *)bprm->p - items - ei_index;
+	bprm->exec = (unsigned long)sp; /* XXX: PARISC HACK */
+#else
+	sp = (elf_addr_t __user *)bprm->p;
+#endif
+
+
+	/*
+	 * Grow the stack manually; some architectures have a limit on how
+	 * far ahead a user-space access may be in order to grow the stack.
+	 */
+	vma = find_extend_vma(current->mm, bprm->p);
+	if (!vma)
+		return -EFAULT;
+
+	/* Now, let's put argc (and argv, envp if appropriate) on the stack */
+	if (__put_user(argc, sp++))
+		return -EFAULT;
+
+	/* Populate list of argv pointers back to argv strings. */
+	p = current->mm->arg_end = current->mm->arg_start;
+	while (argc-- > 0) {
+		size_t len;
+		if (__put_user((elf_addr_t)p, sp++))
+			return -EFAULT;
+		len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
+		if (!len || len > MAX_ARG_STRLEN)
+			return -EINVAL;
+		p += len;
+	}
+	if (__put_user(0, sp++))
+		return -EFAULT;
+	current->mm->arg_end = p;
+
+	/* Populate list of envp pointers back to envp strings. */
+	current->mm->env_end = current->mm->env_start = p;
+	while (envc-- > 0) {
+		size_t len;
+		if (__put_user((elf_addr_t)p, sp++))
+			return -EFAULT;
+		len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
+		if (!len || len > MAX_ARG_STRLEN)
+			return -EINVAL;
+		p += len;
+	}
+	if (__put_user(0, sp++))
+		return -EFAULT;
+	current->mm->env_end = p;
+
+	/* Put the elf_info on the stack in the right place.  */
+	if (copy_to_user(sp, elf_info, ei_index * sizeof(elf_addr_t)))
+		return -EFAULT;
+	return 0;
+}
+
+#ifndef elf_map
+
+static unsigned long elf_map(struct file *filep, unsigned long addr,
+		struct elf_phdr *eppnt, int prot, int type,
+		unsigned long total_size)
+{
+	unsigned long map_addr;
+	unsigned long size = eppnt->p_filesz + ELF_PAGEOFFSET(eppnt->p_vaddr);
+	unsigned long off = eppnt->p_offset - ELF_PAGEOFFSET(eppnt->p_vaddr);
+	addr = ELF_PAGESTART(addr);
+	size = ELF_PAGEALIGN(size);
+
+	/* mmap() will return -EINVAL if given a zero size, but a
+	 * segment with zero filesize is perfectly valid */
+	if (!size)
+		return addr;
+
+	/*
+	* total_size is the size of the ELF (interpreter) image.
+	* The _first_ mmap needs to know the full size, otherwise
+	* randomization might put this image into an overlapping
+	* position with the ELF binary image. (since size < total_size)
+	* So we first map the 'big' image - and unmap the remainder at
+	* the end. (which unmap is needed for ELF images with holes.)
+	*/
+	if (total_size) {
+		total_size = ELF_PAGEALIGN(total_size);
+		map_addr = vm_mmap(filep, addr, total_size, prot, type, off);
+		if (!BAD_ADDR(map_addr))
+			vm_munmap(map_addr+size, total_size-size);
+	} else
+		map_addr = vm_mmap(filep, addr, size, prot, type, off);
+
+	if ((type & MAP_FIXED_NOREPLACE) &&
+	    PTR_ERR((void *)map_addr) == -EEXIST)
+		pr_info("%d (%s): Uhuuh, elf segment at %px requested but the memory is mapped already\n",
+			task_pid_nr(current), current->comm, (void *)addr);
+
+	return(map_addr);
+}
+
+#endif /* !elf_map */
+
+static unsigned long total_mapping_size(struct elf_phdr *cmds, int nr)
+{
+	int i, first_idx = -1, last_idx = -1;
+
+	for (i = 0; i < nr; i++) {
+		if (cmds[i].p_type == PT_LOAD) {
+			last_idx = i;
+			if (first_idx == -1)
+				first_idx = i;
+		}
+	}
+	if (first_idx == -1)
+		return 0;
+
+	return cmds[last_idx].p_vaddr + cmds[last_idx].p_memsz -
+				ELF_PAGESTART(cmds[first_idx].p_vaddr);
+}
+
+/**
+ * load_elf_phdrs() - load ELF program headers
+ * @elf_ex:   ELF header of the binary whose program headers should be loaded
+ * @elf_file: the opened ELF binary file
+ *
+ * Loads ELF program headers from the binary file elf_file, which has the ELF
+ * header pointed to by elf_ex, into a newly allocated array. The caller is
+ * responsible for freeing the allocated data. Returns an ERR_PTR upon failure.
+ */
+static struct elf_phdr *load_elf_phdrs(struct elfhdr *elf_ex,
+				       struct file *elf_file)
+{
+	struct elf_phdr *elf_phdata = NULL;
+	int retval, size, err = -1;
+	loff_t pos = elf_ex->e_phoff;
+
+	/*
+	 * If the size of this structure has changed, then punt, since
+	 * we will be doing the wrong thing.
+	 */
+	if (elf_ex->e_phentsize != sizeof(struct elf_phdr))
+		goto out;
+
+	/* Sanity check the number of program headers... */
+	if (elf_ex->e_phnum < 1 ||
+		elf_ex->e_phnum > 65536U / sizeof(struct elf_phdr))
+		goto out;
+
+	/* ...and their total size. */
+	size = sizeof(struct elf_phdr) * elf_ex->e_phnum;
+	if (size > ELF_MIN_ALIGN)
+		goto out;
+
+	elf_phdata = kmalloc(size, GFP_KERNEL);
+	if (!elf_phdata)
+		goto out;
+
+	/* Read in the program headers */
+	retval = kernel_read(elf_file, elf_phdata, size, &pos);
+	if (retval != size) {
+		err = (retval < 0) ? retval : -EIO;
+		goto out;
+	}
+
+	/* Success! */
+	err = 0;
+out:
+	if (err) {
+		kfree(elf_phdata);
+		elf_phdata = NULL;
+	}
+	return elf_phdata;
+}
+
+#ifndef CONFIG_ARCH_BINFMT_ELF_STATE
+
+/**
+ * struct arch_elf_state - arch-specific ELF loading state
+ *
+ * This structure is used to preserve architecture specific data during
+ * the loading of an ELF file, throughout the checking of architecture
+ * specific ELF headers & through to the point where the ELF load is
+ * known to be proceeding (ie. SET_PERSONALITY).
+ *
+ * This implementation is a dummy for architectures which require no
+ * specific state.
+ */
+struct arch_elf_state {
+};
+
+#define INIT_ARCH_ELF_STATE {}
+
+/**
+ * arch_elf_pt_proc() - check a PT_LOPROC..PT_HIPROC ELF program header
+ * @ehdr:	The main ELF header
+ * @phdr:	The program header to check
+ * @elf:	The open ELF file
+ * @is_interp:	True if the phdr is from the interpreter of the ELF being
+ *		loaded, else false.
+ * @state:	Architecture-specific state preserved throughout the process
+ *		of loading the ELF.
+ *
+ * Inspects the program header phdr to validate its correctness and/or
+ * suitability for the system. Called once per ELF program header in the
+ * range PT_LOPROC to PT_HIPROC, for both the ELF being loaded and its
+ * interpreter.
+ *
+ * Return: Zero to proceed with the ELF load, non-zero to fail the ELF load
+ *         with that return code.
+ */
+static inline int arch_elf_pt_proc(struct elfhdr *ehdr,
+				   struct elf_phdr *phdr,
+				   struct file *elf, bool is_interp,
+				   struct arch_elf_state *state)
+{
+	/* Dummy implementation, always proceed */
+	return 0;
+}
+
+/**
+ * arch_check_elf() - check an ELF executable
+ * @ehdr:	The main ELF header
+ * @has_interp:	True if the ELF has an interpreter, else false.
+ * @interp_ehdr: The interpreter's ELF header
+ * @state:	Architecture-specific state preserved throughout the process
+ *		of loading the ELF.
+ *
+ * Provides a final opportunity for architecture code to reject the loading
+ * of the ELF & cause an exec syscall to return an error. This is called after
+ * all program headers to be checked by arch_elf_pt_proc have been.
+ *
+ * Return: Zero to proceed with the ELF load, non-zero to fail the ELF load
+ *         with that return code.
+ */
+static inline int arch_check_elf(struct elfhdr *ehdr, bool has_interp,
+				 struct elfhdr *interp_ehdr,
+				 struct arch_elf_state *state)
+{
+	/* Dummy implementation, always proceed */
+	return 0;
+}
+
+#endif /* !CONFIG_ARCH_BINFMT_ELF_STATE */
+
+/* This is much more generalized than the library routine read function,
+   so we keep this separate.  Technically the library read function
+   is only provided so that we can read a.out libraries that have
+   an ELF header */
+
+static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
+		struct file *interpreter, unsigned long *interp_map_addr,
+		unsigned long no_base, struct elf_phdr *interp_elf_phdata)
+{
+	struct elf_phdr *eppnt;
+	unsigned long load_addr = 0;
+	int load_addr_set = 0;
+	unsigned long last_bss = 0, elf_bss = 0;
+	int bss_prot = 0;
+	unsigned long error = ~0UL;
+	unsigned long total_size;
+	int i;
+
+	/* First of all, some simple consistency checks */
+	if (interp_elf_ex->e_type != ET_EXEC &&
+	    interp_elf_ex->e_type != ET_DYN)
+		goto out;
+	if (!elf_check_arch(interp_elf_ex) ||
+	    elf_check_fdpic(interp_elf_ex))
+		goto out;
+	if (!interpreter->f_op->mmap)
+		goto out;
+
+	total_size = total_mapping_size(interp_elf_phdata,
+					interp_elf_ex->e_phnum);
+	if (!total_size) {
+		error = -EINVAL;
+		goto out;
+	}
+
+	eppnt = interp_elf_phdata;
+	for (i = 0; i < interp_elf_ex->e_phnum; i++, eppnt++) {
+		if (eppnt->p_type == PT_LOAD) {
+			int elf_type = MAP_PRIVATE | MAP_DENYWRITE;
+			int elf_prot = 0;
+			unsigned long vaddr = 0;
+			unsigned long k, map_addr;
+
+			if (eppnt->p_flags & PF_R)
+		    		elf_prot = PROT_READ;
+			if (eppnt->p_flags & PF_W)
+				elf_prot |= PROT_WRITE;
+			if (eppnt->p_flags & PF_X)
+				elf_prot |= PROT_EXEC;
+			vaddr = eppnt->p_vaddr;
+			if (interp_elf_ex->e_type == ET_EXEC || load_addr_set)
+				elf_type |= MAP_FIXED;
+			else if (no_base && interp_elf_ex->e_type == ET_DYN)
+				load_addr = -vaddr;
+
+			map_addr = elf_map(interpreter, load_addr + vaddr,
+					eppnt, elf_prot, elf_type, total_size);
+			total_size = 0;
+			if (!*interp_map_addr)
+				*interp_map_addr = map_addr;
+			error = map_addr;
+			if (BAD_ADDR(map_addr))
+				goto out;
+
+			if (!load_addr_set &&
+			    interp_elf_ex->e_type == ET_DYN) {
+				load_addr = map_addr - ELF_PAGESTART(vaddr);
+				load_addr_set = 1;
+			}
+
+			/*
+			 * Check to see if the section's size will overflow the
+			 * allowed task size. Note that p_filesz must always be
+			 * <= p_memsize so it's only necessary to check p_memsz.
+			 */
+			k = load_addr + eppnt->p_vaddr;
+			if (BAD_ADDR(k) ||
+			    eppnt->p_filesz > eppnt->p_memsz ||
+			    eppnt->p_memsz > TASK_SIZE ||
+			    TASK_SIZE - eppnt->p_memsz < k) {
+				error = -ENOMEM;
+				goto out;
+			}
+
+			/*
+			 * Find the end of the file mapping for this phdr, and
+			 * keep track of the largest address we see for this.
+			 */
+			k = load_addr + eppnt->p_vaddr + eppnt->p_filesz;
+			if (k > elf_bss)
+				elf_bss = k;
+
+			/*
+			 * Do the same thing for the memory mapping - between
+			 * elf_bss and last_bss is the bss section.
+			 */
+			k = load_addr + eppnt->p_vaddr + eppnt->p_memsz;
+			if (k > last_bss) {
+				last_bss = k;
+				bss_prot = elf_prot;
+			}
+		}
+	}
+
+	/*
+	 * Now fill out the bss section: first pad the last page from
+	 * the file up to the page boundary, and zero it from elf_bss
+	 * up to the end of the page.
+	 */
+	if (padzero(elf_bss)) {
+		error = -EFAULT;
+		goto out;
+	}
+	/*
+	 * Next, align both the file and mem bss up to the page size,
+	 * since this is where elf_bss was just zeroed up to, and where
+	 * last_bss will end after the vm_brk_flags() below.
+	 */
+	elf_bss = ELF_PAGEALIGN(elf_bss);
+	last_bss = ELF_PAGEALIGN(last_bss);
+	/* Finally, if there is still more bss to allocate, do it. */
+	if (last_bss > elf_bss) {
+		error = vm_brk_flags(elf_bss, last_bss - elf_bss,
+				bss_prot & PROT_EXEC ? VM_EXEC : 0);
+		if (error)
+			goto out;
+	}
+
+	error = load_addr;
+out:
+	return error;
+}
+
+/*
+ * These are the functions used to load ELF style executables and shared
+ * libraries.  There is no binary dependent code anywhere else.
+ */
+
+#ifndef STACK_RND_MASK
+#define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12))	/* 8MB of VA */
+#endif
+
+static unsigned long randomize_stack_top(unsigned long stack_top)
+{
+	unsigned long random_variable = 0;
+
+	if (current->flags & PF_RANDOMIZE) {
+		random_variable = get_random_long();
+		random_variable &= STACK_RND_MASK;
+		random_variable <<= PAGE_SHIFT;
+	}
+#ifdef CONFIG_STACK_GROWSUP
+	return PAGE_ALIGN(stack_top) + random_variable;
+#else
+	return PAGE_ALIGN(stack_top) - random_variable;
+#endif
+}
+
+static int load_elf_binary(struct linux_binprm *bprm)
+{
+	struct file *interpreter = NULL; /* to shut gcc up */
+ 	unsigned long load_addr = 0, load_bias = 0;
+	int load_addr_set = 0;
+	char * elf_interpreter = NULL;
+	unsigned long error;
+	struct elf_phdr *elf_ppnt, *elf_phdata, *interp_elf_phdata = NULL;
+	unsigned long elf_bss, elf_brk;
+	int bss_prot = 0;
+	int retval, i;
+	unsigned long elf_entry;
+	unsigned long interp_load_addr = 0;
+	unsigned long start_code, end_code, start_data, end_data;
+	unsigned long reloc_func_desc __maybe_unused = 0;
+	int executable_stack = EXSTACK_DEFAULT;
+	struct pt_regs *regs = current_pt_regs();
+	struct {
+		struct elfhdr elf_ex;
+		struct elfhdr interp_elf_ex;
+	} *loc;
+	struct arch_elf_state arch_state = INIT_ARCH_ELF_STATE;
+	loff_t pos;
+
+	loc = kmalloc(sizeof(*loc), GFP_KERNEL);
+	if (!loc) {
+		retval = -ENOMEM;
+		goto out_ret;
+	}
+	
+	/* Get the exec-header */
+	loc->elf_ex = *((struct elfhdr *)bprm->buf);
+
+	retval = -ENOEXEC;
+	/* First of all, some simple consistency checks */
+	if (memcmp(loc->elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
+		goto out;
+
+	if (loc->elf_ex.e_type != ET_EXEC && loc->elf_ex.e_type != ET_DYN)
+		goto out;
+	if (!elf_check_arch(&loc->elf_ex))
+		goto out;
+	if (elf_check_fdpic(&loc->elf_ex))
+		goto out;
+	if (!bprm->file->f_op->mmap)
+		goto out;
+
+	elf_phdata = load_elf_phdrs(&loc->elf_ex, bprm->file);
+	if (!elf_phdata)
+		goto out;
+
+	elf_ppnt = elf_phdata;
+	elf_bss = 0;
+	elf_brk = 0;
+
+	start_code = ~0UL;
+	end_code = 0;
+	start_data = 0;
+	end_data = 0;
+
+	for (i = 0; i < loc->elf_ex.e_phnum; i++) {
+		if (elf_ppnt->p_type == PT_INTERP) {
+			/* This is the program interpreter used for
+			 * shared libraries - for now assume that this
+			 * is an a.out format binary
+			 */
+			retval = -ENOEXEC;
+			if (elf_ppnt->p_filesz > PATH_MAX || 
+			    elf_ppnt->p_filesz < 2)
+				goto out_free_ph;
+
+			retval = -ENOMEM;
+			elf_interpreter = kmalloc(elf_ppnt->p_filesz,
+						  GFP_KERNEL);
+			if (!elf_interpreter)
+				goto out_free_ph;
+
+			pos = elf_ppnt->p_offset;
+			retval = kernel_read(bprm->file, elf_interpreter,
+					     elf_ppnt->p_filesz, &pos);
+			if (retval != elf_ppnt->p_filesz) {
+				if (retval >= 0)
+					retval = -EIO;
+				goto out_free_interp;
+			}
+			/* make sure path is NULL terminated */
+			retval = -ENOEXEC;
+			if (elf_interpreter[elf_ppnt->p_filesz - 1] != '\0')
+				goto out_free_interp;
+
+			interpreter = open_exec(elf_interpreter);
+			retval = PTR_ERR(interpreter);
+			if (IS_ERR(interpreter))
+				goto out_free_interp;
+
+			/*
+			 * If the binary is not readable then enforce
+			 * mm->dumpable = 0 regardless of the interpreter's
+			 * permissions.
+			 */
+			would_dump(bprm, interpreter);
+
+			/* Get the exec headers */
+			pos = 0;
+			retval = kernel_read(interpreter, &loc->interp_elf_ex,
+					     sizeof(loc->interp_elf_ex), &pos);
+			if (retval != sizeof(loc->interp_elf_ex)) {
+				if (retval >= 0)
+					retval = -EIO;
+				goto out_free_dentry;
+			}
+
+			break;
+		}
+		elf_ppnt++;
+	}
+
+	elf_ppnt = elf_phdata;
+	for (i = 0; i < loc->elf_ex.e_phnum; i++, elf_ppnt++)
+		switch (elf_ppnt->p_type) {
+		case PT_GNU_STACK:
+			if (elf_ppnt->p_flags & PF_X)
+				executable_stack = EXSTACK_ENABLE_X;
+			else
+				executable_stack = EXSTACK_DISABLE_X;
+			break;
+
+		case PT_LOPROC ... PT_HIPROC:
+			retval = arch_elf_pt_proc(&loc->elf_ex, elf_ppnt,
+						  bprm->file, false,
+						  &arch_state);
+			if (retval)
+				goto out_free_dentry;
+			break;
+		}
+
+	/* Some simple consistency checks for the interpreter */
+	if (elf_interpreter) {
+		retval = -ELIBBAD;
+		/* Not an ELF interpreter */
+		if (memcmp(loc->interp_elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
+			goto out_free_dentry;
+		/* Verify the interpreter has a valid arch */
+		if (!elf_check_arch(&loc->interp_elf_ex) ||
+		    elf_check_fdpic(&loc->interp_elf_ex))
+			goto out_free_dentry;
+
+		/* Load the interpreter program headers */
+		interp_elf_phdata = load_elf_phdrs(&loc->interp_elf_ex,
+						   interpreter);
+		if (!interp_elf_phdata)
+			goto out_free_dentry;
+
+		/* Pass PT_LOPROC..PT_HIPROC headers to arch code */
+		elf_ppnt = interp_elf_phdata;
+		for (i = 0; i < loc->interp_elf_ex.e_phnum; i++, elf_ppnt++)
+			switch (elf_ppnt->p_type) {
+			case PT_LOPROC ... PT_HIPROC:
+				retval = arch_elf_pt_proc(&loc->interp_elf_ex,
+							  elf_ppnt, interpreter,
+							  true, &arch_state);
+				if (retval)
+					goto out_free_dentry;
+				break;
+			}
+	}
+
+	/*
+	 * Allow arch code to reject the ELF at this point, whilst it's
+	 * still possible to return an error to the code that invoked
+	 * the exec syscall.
+	 */
+	retval = arch_check_elf(&loc->elf_ex,
+				!!interpreter, &loc->interp_elf_ex,
+				&arch_state);
+	if (retval)
+		goto out_free_dentry;
+
+	/* Flush all traces of the currently running executable */
+	retval = flush_old_exec(bprm);
+	if (retval)
+		goto out_free_dentry;
+
+	/* Do this immediately, since STACK_TOP as used in setup_arg_pages
+	   may depend on the personality.  */
+	SET_PERSONALITY2(loc->elf_ex, &arch_state);
+	if (elf_read_implies_exec(loc->elf_ex, executable_stack))
+		current->personality |= READ_IMPLIES_EXEC;
+
+	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
+		current->flags |= PF_RANDOMIZE;
+
+	setup_new_exec(bprm);
+	install_exec_creds(bprm);
+
+	/* Do this so that we can load the interpreter, if need be.  We will
+	   change some of these later */
+	retval = setup_arg_pages(bprm, randomize_stack_top(STACK_TOP),
+				 executable_stack);
+	if (retval < 0)
+		goto out_free_dentry;
+	
+	current->mm->start_stack = bprm->p;
+
+	/* Now we do a little grungy work by mmapping the ELF image into
+	   the correct location in memory. */
+	for(i = 0, elf_ppnt = elf_phdata;
+	    i < loc->elf_ex.e_phnum; i++, elf_ppnt++) {
+		int elf_prot = 0, elf_flags, elf_fixed = MAP_FIXED_NOREPLACE;
+		unsigned long k, vaddr;
+		unsigned long total_size = 0;
+
+		if (elf_ppnt->p_type != PT_LOAD)
+			continue;
+
+		if (unlikely (elf_brk > elf_bss)) {
+			unsigned long nbyte;
+	            
+			/* There was a PT_LOAD segment with p_memsz > p_filesz
+			   before this one. Map anonymous pages, if needed,
+			   and clear the area.  */
+			retval = set_brk(elf_bss + load_bias,
+					 elf_brk + load_bias,
+					 bss_prot);
+			if (retval)
+				goto out_free_dentry;
+			nbyte = ELF_PAGEOFFSET(elf_bss);
+			if (nbyte) {
+				nbyte = ELF_MIN_ALIGN - nbyte;
+				if (nbyte > elf_brk - elf_bss)
+					nbyte = elf_brk - elf_bss;
+				if (clear_user((void __user *)elf_bss +
+							load_bias, nbyte)) {
+					/*
+					 * This bss-zeroing can fail if the ELF
+					 * file specifies odd protections. So
+					 * we don't check the return value
+					 */
+				}
+			}
+
+			/*
+			 * Some binaries have overlapping elf segments and then
+			 * we have to forcefully map over an existing mapping
+			 * e.g. over this newly established brk mapping.
+			 */
+			elf_fixed = MAP_FIXED;
+		}
+
+		if (elf_ppnt->p_flags & PF_R)
+			elf_prot |= PROT_READ;
+		if (elf_ppnt->p_flags & PF_W)
+			elf_prot |= PROT_WRITE;
+		if (elf_ppnt->p_flags & PF_X)
+			elf_prot |= PROT_EXEC;
+
+		elf_flags = MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE;
+
+		vaddr = elf_ppnt->p_vaddr;
+		/*
+		 * If we are loading ET_EXEC or we have already performed
+		 * the ET_DYN load_addr calculations, proceed normally.
+		 */
+		if (loc->elf_ex.e_type == ET_EXEC || load_addr_set) {
+			elf_flags |= elf_fixed;
+		} else if (loc->elf_ex.e_type == ET_DYN) {
+			/*
+			 * This logic is run once for the first LOAD Program
+			 * Header for ET_DYN binaries to calculate the
+			 * randomization (load_bias) for all the LOAD
+			 * Program Headers, and to calculate the entire
+			 * size of the ELF mapping (total_size). (Note that
+			 * load_addr_set is set to true later once the
+			 * initial mapping is performed.)
+			 *
+			 * There are effectively two types of ET_DYN
+			 * binaries: programs (i.e. PIE: ET_DYN with INTERP)
+			 * and loaders (ET_DYN without INTERP, since they
+			 * _are_ the ELF interpreter). The loaders must
+			 * be loaded away from programs since the program
+			 * may otherwise collide with the loader (especially
+			 * for ET_EXEC which does not have a randomized
+			 * position). For example to handle invocations of
+			 * "./ld.so someprog" to test out a new version of
+			 * the loader, the subsequent program that the
+			 * loader loads must avoid the loader itself, so
+			 * they cannot share the same load range. Sufficient
+			 * room for the brk must be allocated with the
+			 * loader as well, since brk must be available with
+			 * the loader.
+			 *
+			 * Therefore, programs are loaded offset from
+			 * ELF_ET_DYN_BASE and loaders are loaded into the
+			 * independently randomized mmap region (0 load_bias
+			 * without MAP_FIXED).
+			 */
+			if (elf_interpreter) {
+				load_bias = ELF_ET_DYN_BASE;
+				if (current->flags & PF_RANDOMIZE)
+					load_bias += arch_mmap_rnd();
+				elf_flags |= elf_fixed;
+			} else
+				load_bias = 0;
+
+			/*
+			 * Since load_bias is used for all subsequent loading
+			 * calculations, we must lower it by the first vaddr
+			 * so that the remaining calculations based on the
+			 * ELF vaddrs will be correctly offset. The result
+			 * is then page aligned.
+			 */
+			load_bias = ELF_PAGESTART(load_bias - vaddr);
+
+			total_size = total_mapping_size(elf_phdata,
+							loc->elf_ex.e_phnum);
+			if (!total_size) {
+				retval = -EINVAL;
+				goto out_free_dentry;
+			}
+		}
+
+		error = elf_map(bprm->file, load_bias + vaddr, elf_ppnt,
+				elf_prot, elf_flags, total_size);
+		if (BAD_ADDR(error)) {
+			retval = IS_ERR((void *)error) ?
+				PTR_ERR((void*)error) : -EINVAL;
+			goto out_free_dentry;
+		}
+
+		if (!load_addr_set) {
+			load_addr_set = 1;
+			load_addr = (elf_ppnt->p_vaddr - elf_ppnt->p_offset);
+			if (loc->elf_ex.e_type == ET_DYN) {
+				load_bias += error -
+				             ELF_PAGESTART(load_bias + vaddr);
+				load_addr += load_bias;
+				reloc_func_desc = load_bias;
+			}
+		}
+		k = elf_ppnt->p_vaddr;
+		if (k < start_code)
+			start_code = k;
+		if (start_data < k)
+			start_data = k;
+
+		/*
+		 * Check to see if the section's size will overflow the
+		 * allowed task size. Note that p_filesz must always be
+		 * <= p_memsz so it is only necessary to check p_memsz.
+		 */
+		if (BAD_ADDR(k) || elf_ppnt->p_filesz > elf_ppnt->p_memsz ||
+		    elf_ppnt->p_memsz > TASK_SIZE ||
+		    TASK_SIZE - elf_ppnt->p_memsz < k) {
+			/* set_brk can never work. Avoid overflows. */
+			retval = -EINVAL;
+			goto out_free_dentry;
+		}
+
+		k = elf_ppnt->p_vaddr + elf_ppnt->p_filesz;
+
+		if (k > elf_bss)
+			elf_bss = k;
+		if ((elf_ppnt->p_flags & PF_X) && end_code < k)
+			end_code = k;
+		if (end_data < k)
+			end_data = k;
+		k = elf_ppnt->p_vaddr + elf_ppnt->p_memsz;
+		if (k > elf_brk) {
+			bss_prot = elf_prot;
+			elf_brk = k;
+		}
+	}
+
+	loc->elf_ex.e_entry += load_bias;
+	elf_bss += load_bias;
+	elf_brk += load_bias;
+	start_code += load_bias;
+	end_code += load_bias;
+	start_data += load_bias;
+	end_data += load_bias;
+
+	/* Calling set_brk effectively mmaps the pages that we need
+	 * for the bss and break sections.  We must do this before
+	 * mapping in the interpreter, to make sure it doesn't wind
+	 * up getting placed where the bss needs to go.
+	 */
+	retval = set_brk(elf_bss, elf_brk, bss_prot);
+	if (retval)
+		goto out_free_dentry;
+	if (likely(elf_bss != elf_brk) && unlikely(padzero(elf_bss))) {
+		retval = -EFAULT; /* Nobody gets to see this, but.. */
+		goto out_free_dentry;
+	}
+
+	if (elf_interpreter) {
+		unsigned long interp_map_addr = 0;
+
+		elf_entry = load_elf_interp(&loc->interp_elf_ex,
+					    interpreter,
+					    &interp_map_addr,
+					    load_bias, interp_elf_phdata);
+		if (!IS_ERR((void *)elf_entry)) {
+			/*
+			 * load_elf_interp() returns relocation
+			 * adjustment
+			 */
+			interp_load_addr = elf_entry;
+			elf_entry += loc->interp_elf_ex.e_entry;
+		}
+		if (BAD_ADDR(elf_entry)) {
+			retval = IS_ERR((void *)elf_entry) ?
+					(int)elf_entry : -EINVAL;
+			goto out_free_dentry;
+		}
+		reloc_func_desc = interp_load_addr;
+
+		allow_write_access(interpreter);
+		fput(interpreter);
+		kfree(elf_interpreter);
+	} else {
+		elf_entry = loc->elf_ex.e_entry;
+		if (BAD_ADDR(elf_entry)) {
+			retval = -EINVAL;
+			goto out_free_dentry;
+		}
+	}
+
+	kfree(interp_elf_phdata);
+	kfree(elf_phdata);
+
+	set_binfmt(&elf_format);
+
+#ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
+	retval = arch_setup_additional_pages(bprm, !!elf_interpreter);
+	if (retval < 0)
+		goto out;
+#endif /* ARCH_HAS_SETUP_ADDITIONAL_PAGES */
+
+	retval = create_elf_tables(bprm, &loc->elf_ex,
+			  load_addr, interp_load_addr);
+	if (retval < 0)
+		goto out;
+	/* N.B. passed_fileno might not be initialized? */
+	current->mm->end_code = end_code;
+	current->mm->start_code = start_code;
+	current->mm->start_data = start_data;
+	current->mm->end_data = end_data;
+	current->mm->start_stack = bprm->p;
+
+	if ((current->flags & PF_RANDOMIZE) && (randomize_va_space > 1)) {
+		/*
+		 * For architectures with ELF randomization, when executing
+		 * a loader directly (i.e. no interpreter listed in ELF
+		 * headers), move the brk area out of the mmap region
+		 * (since it grows up, and may collide early with the stack
+		 * growing down), and into the unused ELF_ET_DYN_BASE region.
+		 */
+		if (IS_ENABLED(CONFIG_ARCH_HAS_ELF_RANDOMIZE) &&
+		    loc->elf_ex.e_type == ET_DYN && !interpreter)
+			current->mm->brk = current->mm->start_brk =
+				ELF_ET_DYN_BASE;
+
+		current->mm->brk = current->mm->start_brk =
+			arch_randomize_brk(current->mm);
+#ifdef compat_brk_randomized
+		current->brk_randomized = 1;
+#endif
+	}
+
+	if (current->personality & MMAP_PAGE_ZERO) {
+		/* Why this, you ask???  Well SVr4 maps page 0 as read-only,
+		   and some applications "depend" upon this behavior.
+		   Since we do not have the power to recompile these, we
+		   emulate the SVr4 behavior. Sigh. */
+		error = vm_mmap(NULL, 0, PAGE_SIZE, PROT_READ | PROT_EXEC,
+				MAP_FIXED | MAP_PRIVATE, 0);
+	}
+
+#ifdef ELF_PLAT_INIT
+	/*
+	 * The ABI may specify that certain registers be set up in special
+	 * ways (on i386 %edx is the address of a DT_FINI function, for
+	 * example.  In addition, it may also specify (eg, PowerPC64 ELF)
+	 * that the e_entry field is the address of the function descriptor
+	 * for the startup routine, rather than the address of the startup
+	 * routine itself.  This macro performs whatever initialization to
+	 * the regs structure is required as well as any relocations to the
+	 * function descriptor entries when executing dynamically links apps.
+	 */
+	ELF_PLAT_INIT(regs, reloc_func_desc);
+#endif
+
+	finalize_exec(bprm);
+	start_thread(regs, elf_entry, bprm->p);
+	retval = 0;
+out:
+	kfree(loc);
+out_ret:
+	return retval;
+
+	/* error cleanup */
+out_free_dentry:
+	kfree(interp_elf_phdata);
+	allow_write_access(interpreter);
+	if (interpreter)
+		fput(interpreter);
+out_free_interp:
+	kfree(elf_interpreter);
+out_free_ph:
+	kfree(elf_phdata);
+	goto out;
+}
+
+#ifdef CONFIG_USELIB
+/* This is really simpleminded and specialized - we are loading an
+   a.out library that is given an ELF header. */
+static int load_elf_library(struct file *file)
+{
+	struct elf_phdr *elf_phdata;
+	struct elf_phdr *eppnt;
+	unsigned long elf_bss, bss, len;
+	int retval, error, i, j;
+	struct elfhdr elf_ex;
+	loff_t pos = 0;
+
+	error = -ENOEXEC;
+	retval = kernel_read(file, &elf_ex, sizeof(elf_ex), &pos);
+	if (retval != sizeof(elf_ex))
+		goto out;
+
+	if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
+		goto out;
+
+	/* First of all, some simple consistency checks */
+	if (elf_ex.e_type != ET_EXEC || elf_ex.e_phnum > 2 ||
+	    !elf_check_arch(&elf_ex) || !file->f_op->mmap)
+		goto out;
+	if (elf_check_fdpic(&elf_ex))
+		goto out;
+
+	/* Now read in all of the header information */
+
+	j = sizeof(struct elf_phdr) * elf_ex.e_phnum;
+	/* j < ELF_MIN_ALIGN because elf_ex.e_phnum <= 2 */
+
+	error = -ENOMEM;
+	elf_phdata = kmalloc(j, GFP_KERNEL);
+	if (!elf_phdata)
+		goto out;
+
+	eppnt = elf_phdata;
+	error = -ENOEXEC;
+	pos =  elf_ex.e_phoff;
+	retval = kernel_read(file, eppnt, j, &pos);
+	if (retval != j)
+		goto out_free_ph;
+
+	for (j = 0, i = 0; i<elf_ex.e_phnum; i++)
+		if ((eppnt + i)->p_type == PT_LOAD)
+			j++;
+	if (j != 1)
+		goto out_free_ph;
+
+	while (eppnt->p_type != PT_LOAD)
+		eppnt++;
+
+	/* Now use mmap to map the library into memory. */
+	error = vm_mmap(file,
+			ELF_PAGESTART(eppnt->p_vaddr),
+			(eppnt->p_filesz +
+			 ELF_PAGEOFFSET(eppnt->p_vaddr)),
+			PROT_READ | PROT_WRITE | PROT_EXEC,
+			MAP_FIXED_NOREPLACE | MAP_PRIVATE | MAP_DENYWRITE,
+			(eppnt->p_offset -
+			 ELF_PAGEOFFSET(eppnt->p_vaddr)));
+	if (error != ELF_PAGESTART(eppnt->p_vaddr))
+		goto out_free_ph;
+
+	elf_bss = eppnt->p_vaddr + eppnt->p_filesz;
+	if (padzero(elf_bss)) {
+		error = -EFAULT;
+		goto out_free_ph;
+	}
+
+	len = ELF_PAGEALIGN(eppnt->p_filesz + eppnt->p_vaddr);
+	bss = ELF_PAGEALIGN(eppnt->p_memsz + eppnt->p_vaddr);
+	if (bss > len) {
+		error = vm_brk(len, bss - len);
+		if (error)
+			goto out_free_ph;
+	}
+	error = 0;
+
+out_free_ph:
+	kfree(elf_phdata);
+out:
+	return error;
+}
+#endif /* #ifdef CONFIG_USELIB */
+
+#ifdef CONFIG_ELF_CORE
+/*
+ * ELF core dumper
+ *
+ * Modelled on fs/exec.c:aout_core_dump()
+ * Jeremy Fitzhardinge <jeremy@sw.oz.au>
+ */
+
+/*
+ * The purpose of always_dump_vma() is to make sure that special kernel mappings
+ * that are useful for post-mortem analysis are included in every core dump.
+ * In that way we ensure that the core dump is fully interpretable later
+ * without matching up the same kernel and hardware config to see what PC values
+ * meant. These special mappings include - vDSO, vsyscall, and other
+ * architecture specific mappings
+ */
+static bool always_dump_vma(struct vm_area_struct *vma)
+{
+	/* Any vsyscall mappings? */
+	if (vma == get_gate_vma(vma->vm_mm))
+		return true;
+
+	/*
+	 * Assume that all vmas with a .name op should always be dumped.
+	 * If this changes, a new vm_ops field can easily be added.
+	 */
+	if (vma->vm_ops && vma->vm_ops->name && vma->vm_ops->name(vma))
+		return true;
+
+	/*
+	 * arch_vma_name() returns non-NULL for special architecture mappings,
+	 * such as vDSO sections.
+	 */
+	if (arch_vma_name(vma))
+		return true;
+
+	return false;
+}
+
+/*
+ * Decide what to dump of a segment, part, all or none.
+ */
+static unsigned long vma_dump_size(struct vm_area_struct *vma,
+				   unsigned long mm_flags)
+{
+#define FILTER(type)	(mm_flags & (1UL << MMF_DUMP_##type))
+
+	/* always dump the vdso and vsyscall sections */
+	if (always_dump_vma(vma))
+		goto whole;
+
+	if (vma->vm_flags & VM_DONTDUMP)
+		return 0;
+
+	/* support for DAX */
+	if (vma_is_dax(vma)) {
+		if ((vma->vm_flags & VM_SHARED) && FILTER(DAX_SHARED))
+			goto whole;
+		if (!(vma->vm_flags & VM_SHARED) && FILTER(DAX_PRIVATE))
+			goto whole;
+		return 0;
+	}
+
+	/* Hugetlb memory check */
+	if (vma->vm_flags & VM_HUGETLB) {
+		if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED))
+			goto whole;
+		if (!(vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_PRIVATE))
+			goto whole;
+		return 0;
+	}
+
+	/* Do not dump I/O mapped devices or special mappings */
+	if (vma->vm_flags & VM_IO)
+		return 0;
+
+	/* By default, dump shared memory if mapped from an anonymous file. */
+	if (vma->vm_flags & VM_SHARED) {
+		if (file_inode(vma->vm_file)->i_nlink == 0 ?
+		    FILTER(ANON_SHARED) : FILTER(MAPPED_SHARED))
+			goto whole;
+		return 0;
+	}
+
+	/* Dump segments that have been written to.  */
+	if (vma->anon_vma && FILTER(ANON_PRIVATE))
+		goto whole;
+	if (vma->vm_file == NULL)
+		return 0;
+
+	if (FILTER(MAPPED_PRIVATE))
+		goto whole;
+
+	/*
+	 * If this looks like the beginning of a DSO or executable mapping,
+	 * check for an ELF header.  If we find one, dump the first page to
+	 * aid in determining what was mapped here.
+	 */
+	if (FILTER(ELF_HEADERS) &&
+	    vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ)) {
+		u32 __user *header = (u32 __user *) vma->vm_start;
+		u32 word;
+		mm_segment_t fs = get_fs();
+		/*
+		 * Doing it this way gets the constant folded by GCC.
+		 */
+		union {
+			u32 cmp;
+			char elfmag[SELFMAG];
+		} magic;
+		BUILD_BUG_ON(SELFMAG != sizeof word);
+		magic.elfmag[EI_MAG0] = ELFMAG0;
+		magic.elfmag[EI_MAG1] = ELFMAG1;
+		magic.elfmag[EI_MAG2] = ELFMAG2;
+		magic.elfmag[EI_MAG3] = ELFMAG3;
+		/*
+		 * Switch to the user "segment" for get_user(),
+		 * then put back what elf_core_dump() had in place.
+		 */
+		set_fs(USER_DS);
+		if (unlikely(get_user(word, header)))
+			word = 0;
+		set_fs(fs);
+		if (word == magic.cmp)
+			return PAGE_SIZE;
+	}
+
+#undef	FILTER
+
+	return 0;
+
+whole:
+	return vma->vm_end - vma->vm_start;
+}
+
+/* An ELF note in memory */
+struct memelfnote
+{
+	const char *name;
+	int type;
+	unsigned int datasz;
+	void *data;
+};
+
+static int notesize(struct memelfnote *en)
+{
+	int sz;
+
+	sz = sizeof(struct elf_note);
+	sz += roundup(strlen(en->name) + 1, 4);
+	sz += roundup(en->datasz, 4);
+
+	return sz;
+}
+
+static int writenote(struct memelfnote *men, struct coredump_params *cprm)
+{
+	struct elf_note en;
+	en.n_namesz = strlen(men->name) + 1;
+	en.n_descsz = men->datasz;
+	en.n_type = men->type;
+
+	return dump_emit(cprm, &en, sizeof(en)) &&
+	    dump_emit(cprm, men->name, en.n_namesz) && dump_align(cprm, 4) &&
+	    dump_emit(cprm, men->data, men->datasz) && dump_align(cprm, 4);
+}
+
+static void fill_elf_header(struct elfhdr *elf, int segs,
+			    u16 machine, u32 flags)
+{
+	memset(elf, 0, sizeof(*elf));
+
+	memcpy(elf->e_ident, ELFMAG, SELFMAG);
+	elf->e_ident[EI_CLASS] = ELF_CLASS;
+	elf->e_ident[EI_DATA] = ELF_DATA;
+	elf->e_ident[EI_VERSION] = EV_CURRENT;
+	elf->e_ident[EI_OSABI] = ELF_OSABI;
+
+	elf->e_type = ET_CORE;
+	elf->e_machine = machine;
+	elf->e_version = EV_CURRENT;
+	elf->e_phoff = sizeof(struct elfhdr);
+	elf->e_flags = flags;
+	elf->e_ehsize = sizeof(struct elfhdr);
+	elf->e_phentsize = sizeof(struct elf_phdr);
+	elf->e_phnum = segs;
+
+	return;
+}
+
+static void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
+{
+	phdr->p_type = PT_NOTE;
+	phdr->p_offset = offset;
+	phdr->p_vaddr = 0;
+	phdr->p_paddr = 0;
+	phdr->p_filesz = sz;
+	phdr->p_memsz = 0;
+	phdr->p_flags = 0;
+	phdr->p_align = 0;
+	return;
+}
+
+static void fill_note(struct memelfnote *note, const char *name, int type, 
+		unsigned int sz, void *data)
+{
+	note->name = name;
+	note->type = type;
+	note->datasz = sz;
+	note->data = data;
+	return;
+}
+
+/*
+ * fill up all the fields in prstatus from the given task struct, except
+ * registers which need to be filled up separately.
+ */
+static void fill_prstatus(struct elf_prstatus *prstatus,
+		struct task_struct *p, long signr)
+{
+	prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
+	prstatus->pr_sigpend = p->pending.signal.sig[0];
+	prstatus->pr_sighold = p->blocked.sig[0];
+	rcu_read_lock();
+	prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
+	rcu_read_unlock();
+	prstatus->pr_pid = task_pid_vnr(p);
+	prstatus->pr_pgrp = task_pgrp_vnr(p);
+	prstatus->pr_sid = task_session_vnr(p);
+	if (thread_group_leader(p)) {
+		struct task_cputime cputime;
+
+		/*
+		 * This is the record for the group leader.  It shows the
+		 * group-wide total, not its individual thread total.
+		 */
+		thread_group_cputime(p, &cputime);
+		prstatus->pr_utime = ns_to_timeval(cputime.utime);
+		prstatus->pr_stime = ns_to_timeval(cputime.stime);
+	} else {
+		u64 utime, stime;
+
+		task_cputime(p, &utime, &stime);
+		prstatus->pr_utime = ns_to_timeval(utime);
+		prstatus->pr_stime = ns_to_timeval(stime);
+	}
+
+	prstatus->pr_cutime = ns_to_timeval(p->signal->cutime);
+	prstatus->pr_cstime = ns_to_timeval(p->signal->cstime);
+}
+
+static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
+		       struct mm_struct *mm)
+{
+	const struct cred *cred;
+	unsigned int i, len;
+	
+	/* first copy the parameters from user space */
+	memset(psinfo, 0, sizeof(struct elf_prpsinfo));
+
+	len = mm->arg_end - mm->arg_start;
+	if (len >= ELF_PRARGSZ)
+		len = ELF_PRARGSZ-1;
+	if (copy_from_user(&psinfo->pr_psargs,
+		           (const char __user *)mm->arg_start, len))
+		return -EFAULT;
+	for(i = 0; i < len; i++)
+		if (psinfo->pr_psargs[i] == 0)
+			psinfo->pr_psargs[i] = ' ';
+	psinfo->pr_psargs[len] = 0;
+
+	rcu_read_lock();
+	psinfo->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
+	rcu_read_unlock();
+	psinfo->pr_pid = task_pid_vnr(p);
+	psinfo->pr_pgrp = task_pgrp_vnr(p);
+	psinfo->pr_sid = task_session_vnr(p);
+
+	i = p->state ? ffz(~p->state) + 1 : 0;
+	psinfo->pr_state = i;
+	psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i];
+	psinfo->pr_zomb = psinfo->pr_sname == 'Z';
+	psinfo->pr_nice = task_nice(p);
+	psinfo->pr_flag = p->flags;
+	rcu_read_lock();
+	cred = __task_cred(p);
+	SET_UID(psinfo->pr_uid, from_kuid_munged(cred->user_ns, cred->uid));
+	SET_GID(psinfo->pr_gid, from_kgid_munged(cred->user_ns, cred->gid));
+	rcu_read_unlock();
+	strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));
+	
+	return 0;
+}
+
+static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm)
+{
+	elf_addr_t *auxv = (elf_addr_t *) mm->saved_auxv;
+	int i = 0;
+	do
+		i += 2;
+	while (auxv[i - 2] != AT_NULL);
+	fill_note(note, "CORE", NT_AUXV, i * sizeof(elf_addr_t), auxv);
+}
+
+static void fill_siginfo_note(struct memelfnote *note, user_siginfo_t *csigdata,
+		const siginfo_t *siginfo)
+{
+	mm_segment_t old_fs = get_fs();
+	set_fs(KERNEL_DS);
+	copy_siginfo_to_user((user_siginfo_t __user *) csigdata, siginfo);
+	set_fs(old_fs);
+	fill_note(note, "CORE", NT_SIGINFO, sizeof(*csigdata), csigdata);
+}
+
+#define MAX_FILE_NOTE_SIZE (4*1024*1024)
+/*
+ * Format of NT_FILE note:
+ *
+ * long count     -- how many files are mapped
+ * long page_size -- units for file_ofs
+ * array of [COUNT] elements of
+ *   long start
+ *   long end
+ *   long file_ofs
+ * followed by COUNT filenames in ASCII: "FILE1" NUL "FILE2" NUL...
+ */
+static int fill_files_note(struct memelfnote *note)
+{
+	struct vm_area_struct *vma;
+	unsigned count, size, names_ofs, remaining, n;
+	user_long_t *data;
+	user_long_t *start_end_ofs;
+	char *name_base, *name_curpos;
+
+	/* *Estimated* file count and total data size needed */
+	count = current->mm->map_count;
+	if (count > UINT_MAX / 64)
+		return -EINVAL;
+	size = count * 64;
+
+	names_ofs = (2 + 3 * count) * sizeof(data[0]);
+ alloc:
+	if (size >= MAX_FILE_NOTE_SIZE) /* paranoia check */
+		return -EINVAL;
+	size = round_up(size, PAGE_SIZE);
+	data = kvmalloc(size, GFP_KERNEL);
+	if (ZERO_OR_NULL_PTR(data))
+		return -ENOMEM;
+
+	start_end_ofs = data + 2;
+	name_base = name_curpos = ((char *)data) + names_ofs;
+	remaining = size - names_ofs;
+	count = 0;
+	for (vma = current->mm->mmap; vma != NULL; vma = vma->vm_next) {
+		struct file *file;
+		const char *filename;
+
+		file = vma->vm_file;
+		if (!file)
+			continue;
+		filename = file_path(file, name_curpos, remaining);
+		if (IS_ERR(filename)) {
+			if (PTR_ERR(filename) == -ENAMETOOLONG) {
+				kvfree(data);
+				size = size * 5 / 4;
+				goto alloc;
+			}
+			continue;
+		}
+
+		/* file_path() fills at the end, move name down */
+		/* n = strlen(filename) + 1: */
+		n = (name_curpos + remaining) - filename;
+		remaining = filename - name_curpos;
+		memmove(name_curpos, filename, n);
+		name_curpos += n;
+
+		*start_end_ofs++ = vma->vm_start;
+		*start_end_ofs++ = vma->vm_end;
+		*start_end_ofs++ = vma->vm_pgoff;
+		count++;
+	}
+
+	/* Now we know exact count of files, can store it */
+	data[0] = count;
+	data[1] = PAGE_SIZE;
+	/*
+	 * Count usually is less than current->mm->map_count,
+	 * we need to move filenames down.
+	 */
+	n = current->mm->map_count - count;
+	if (n != 0) {
+		unsigned shift_bytes = n * 3 * sizeof(data[0]);
+		memmove(name_base - shift_bytes, name_base,
+			name_curpos - name_base);
+		name_curpos -= shift_bytes;
+	}
+
+	size = name_curpos - (char *)data;
+	fill_note(note, "CORE", NT_FILE, size, data);
+	return 0;
+}
+
+#ifdef CORE_DUMP_USE_REGSET
+#include <linux/regset.h>
+
+struct elf_thread_core_info {
+	struct elf_thread_core_info *next;
+	struct task_struct *task;
+	struct elf_prstatus prstatus;
+	struct memelfnote notes[0];
+};
+
+struct elf_note_info {
+	struct elf_thread_core_info *thread;
+	struct memelfnote psinfo;
+	struct memelfnote signote;
+	struct memelfnote auxv;
+	struct memelfnote files;
+	user_siginfo_t csigdata;
+	size_t size;
+	int thread_notes;
+};
+
+/*
+ * When a regset has a writeback hook, we call it on each thread before
+ * dumping user memory.  On register window machines, this makes sure the
+ * user memory backing the register data is up to date before we read it.
+ */
+static void do_thread_regset_writeback(struct task_struct *task,
+				       const struct user_regset *regset)
+{
+	if (regset->writeback)
+		regset->writeback(task, regset, 1);
+}
+
+#ifndef PRSTATUS_SIZE
+#define PRSTATUS_SIZE(S, R) sizeof(S)
+#endif
+
+#ifndef SET_PR_FPVALID
+#define SET_PR_FPVALID(S, V, R) ((S)->pr_fpvalid = (V))
+#endif
+
+static int fill_thread_core_info(struct elf_thread_core_info *t,
+				 const struct user_regset_view *view,
+				 long signr, size_t *total)
+{
+	unsigned int i;
+	unsigned int regset0_size = regset_size(t->task, &view->regsets[0]);
+
+	/*
+	 * NT_PRSTATUS is the one special case, because the regset data
+	 * goes into the pr_reg field inside the note contents, rather
+	 * than being the whole note contents.  We fill the reset in here.
+	 * We assume that regset 0 is NT_PRSTATUS.
+	 */
+	fill_prstatus(&t->prstatus, t->task, signr);
+	(void) view->regsets[0].get(t->task, &view->regsets[0], 0, regset0_size,
+				    &t->prstatus.pr_reg, NULL);
+
+	fill_note(&t->notes[0], "CORE", NT_PRSTATUS,
+		  PRSTATUS_SIZE(t->prstatus, regset0_size), &t->prstatus);
+	*total += notesize(&t->notes[0]);
+
+	do_thread_regset_writeback(t->task, &view->regsets[0]);
+
+	/*
+	 * Each other regset might generate a note too.  For each regset
+	 * that has no core_note_type or is inactive, we leave t->notes[i]
+	 * all zero and we'll know to skip writing it later.
+	 */
+	for (i = 1; i < view->n; ++i) {
+		const struct user_regset *regset = &view->regsets[i];
+		do_thread_regset_writeback(t->task, regset);
+		if (regset->core_note_type && regset->get &&
+		    (!regset->active || regset->active(t->task, regset) > 0)) {
+			int ret;
+			size_t size = regset_size(t->task, regset);
+			void *data = kzalloc(size, GFP_KERNEL);
+			if (unlikely(!data))
+				return 0;
+			ret = regset->get(t->task, regset,
+					  0, size, data, NULL);
+			if (unlikely(ret))
+				kfree(data);
+			else {
+				if (regset->core_note_type != NT_PRFPREG)
+					fill_note(&t->notes[i], "LINUX",
+						  regset->core_note_type,
+						  size, data);
+				else {
+					SET_PR_FPVALID(&t->prstatus,
+							1, regset0_size);
+					fill_note(&t->notes[i], "CORE",
+						  NT_PRFPREG, size, data);
+				}
+				*total += notesize(&t->notes[i]);
+			}
+		}
+	}
+
+	return 1;
+}
+
+static int fill_note_info(struct elfhdr *elf, int phdrs,
+			  struct elf_note_info *info,
+			  const siginfo_t *siginfo, struct pt_regs *regs)
+{
+	struct task_struct *dump_task = current;
+	const struct user_regset_view *view = task_user_regset_view(dump_task);
+	struct elf_thread_core_info *t;
+	struct elf_prpsinfo *psinfo;
+	struct core_thread *ct;
+	unsigned int i;
+
+	info->size = 0;
+	info->thread = NULL;
+
+	psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
+	if (psinfo == NULL) {
+		info->psinfo.data = NULL; /* So we don't free this wrongly */
+		return 0;
+	}
+
+	fill_note(&info->psinfo, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
+
+	/*
+	 * Figure out how many notes we're going to need for each thread.
+	 */
+	info->thread_notes = 0;
+	for (i = 0; i < view->n; ++i)
+		if (view->regsets[i].core_note_type != 0)
+			++info->thread_notes;
+
+	/*
+	 * Sanity check.  We rely on regset 0 being in NT_PRSTATUS,
+	 * since it is our one special case.
+	 */
+	if (unlikely(info->thread_notes == 0) ||
+	    unlikely(view->regsets[0].core_note_type != NT_PRSTATUS)) {
+		WARN_ON(1);
+		return 0;
+	}
+
+	/*
+	 * Initialize the ELF file header.
+	 */
+	fill_elf_header(elf, phdrs,
+			view->e_machine, view->e_flags);
+
+	/*
+	 * Allocate a structure for each thread.
+	 */
+	for (ct = &dump_task->mm->core_state->dumper; ct; ct = ct->next) {
+		t = kzalloc(offsetof(struct elf_thread_core_info,
+				     notes[info->thread_notes]),
+			    GFP_KERNEL);
+		if (unlikely(!t))
+			return 0;
+
+		t->task = ct->task;
+		if (ct->task == dump_task || !info->thread) {
+			t->next = info->thread;
+			info->thread = t;
+		} else {
+			/*
+			 * Make sure to keep the original task at
+			 * the head of the list.
+			 */
+			t->next = info->thread->next;
+			info->thread->next = t;
+		}
+	}
+
+	/*
+	 * Now fill in each thread's information.
+	 */
+	for (t = info->thread; t != NULL; t = t->next)
+		if (!fill_thread_core_info(t, view, siginfo->si_signo, &info->size))
+			return 0;
+
+	/*
+	 * Fill in the two process-wide notes.
+	 */
+	fill_psinfo(psinfo, dump_task->group_leader, dump_task->mm);
+	info->size += notesize(&info->psinfo);
+
+	fill_siginfo_note(&info->signote, &info->csigdata, siginfo);
+	info->size += notesize(&info->signote);
+
+	fill_auxv_note(&info->auxv, current->mm);
+	info->size += notesize(&info->auxv);
+
+	if (fill_files_note(&info->files) == 0)
+		info->size += notesize(&info->files);
+
+	return 1;
+}
+
+static size_t get_note_info_size(struct elf_note_info *info)
+{
+	return info->size;
+}
+
+/*
+ * Write all the notes for each thread.  When writing the first thread, the
+ * process-wide notes are interleaved after the first thread-specific note.
+ */
+static int write_note_info(struct elf_note_info *info,
+			   struct coredump_params *cprm)
+{
+	bool first = true;
+	struct elf_thread_core_info *t = info->thread;
+
+	do {
+		int i;
+
+		if (!writenote(&t->notes[0], cprm))
+			return 0;
+
+		if (first && !writenote(&info->psinfo, cprm))
+			return 0;
+		if (first && !writenote(&info->signote, cprm))
+			return 0;
+		if (first && !writenote(&info->auxv, cprm))
+			return 0;
+		if (first && info->files.data &&
+				!writenote(&info->files, cprm))
+			return 0;
+
+		for (i = 1; i < info->thread_notes; ++i)
+			if (t->notes[i].data &&
+			    !writenote(&t->notes[i], cprm))
+				return 0;
+
+		first = false;
+		t = t->next;
+	} while (t);
+
+	return 1;
+}
+
+static void free_note_info(struct elf_note_info *info)
+{
+	struct elf_thread_core_info *threads = info->thread;
+	while (threads) {
+		unsigned int i;
+		struct elf_thread_core_info *t = threads;
+		threads = t->next;
+		WARN_ON(t->notes[0].data && t->notes[0].data != &t->prstatus);
+		for (i = 1; i < info->thread_notes; ++i)
+			kfree(t->notes[i].data);
+		kfree(t);
+	}
+	kfree(info->psinfo.data);
+	kvfree(info->files.data);
+}
+
+#else
+
+/* Here is the structure in which status of each thread is captured. */
+struct elf_thread_status
+{
+	struct list_head list;
+	struct elf_prstatus prstatus;	/* NT_PRSTATUS */
+	elf_fpregset_t fpu;		/* NT_PRFPREG */
+	struct task_struct *thread;
+#ifdef ELF_CORE_COPY_XFPREGS
+	elf_fpxregset_t xfpu;		/* ELF_CORE_XFPREG_TYPE */
+#endif
+	struct memelfnote notes[3];
+	int num_notes;
+};
+
+/*
+ * In order to add the specific thread information for the elf file format,
+ * we need to keep a linked list of every threads pr_status and then create
+ * a single section for them in the final core file.
+ */
+static int elf_dump_thread_status(long signr, struct elf_thread_status *t)
+{
+	int sz = 0;
+	struct task_struct *p = t->thread;
+	t->num_notes = 0;
+
+	fill_prstatus(&t->prstatus, p, signr);
+	elf_core_copy_task_regs(p, &t->prstatus.pr_reg);	
+	
+	fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
+		  &(t->prstatus));
+	t->num_notes++;
+	sz += notesize(&t->notes[0]);
+
+	if ((t->prstatus.pr_fpvalid = elf_core_copy_task_fpregs(p, NULL,
+								&t->fpu))) {
+		fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu),
+			  &(t->fpu));
+		t->num_notes++;
+		sz += notesize(&t->notes[1]);
+	}
+
+#ifdef ELF_CORE_COPY_XFPREGS
+	if (elf_core_copy_task_xfpregs(p, &t->xfpu)) {
+		fill_note(&t->notes[2], "LINUX", ELF_CORE_XFPREG_TYPE,
+			  sizeof(t->xfpu), &t->xfpu);
+		t->num_notes++;
+		sz += notesize(&t->notes[2]);
+	}
+#endif	
+	return sz;
+}
+
+struct elf_note_info {
+	struct memelfnote *notes;
+	struct memelfnote *notes_files;
+	struct elf_prstatus *prstatus;	/* NT_PRSTATUS */
+	struct elf_prpsinfo *psinfo;	/* NT_PRPSINFO */
+	struct list_head thread_list;
+	elf_fpregset_t *fpu;
+#ifdef ELF_CORE_COPY_XFPREGS
+	elf_fpxregset_t *xfpu;
+#endif
+	user_siginfo_t csigdata;
+	int thread_status_size;
+	int numnote;
+};
+
+static int elf_note_info_init(struct elf_note_info *info)
+{
+	memset(info, 0, sizeof(*info));
+	INIT_LIST_HEAD(&info->thread_list);
+
+	/* Allocate space for ELF notes */
+	info->notes = kmalloc_array(8, sizeof(struct memelfnote), GFP_KERNEL);
+	if (!info->notes)
+		return 0;
+	info->psinfo = kmalloc(sizeof(*info->psinfo), GFP_KERNEL);
+	if (!info->psinfo)
+		return 0;
+	info->prstatus = kmalloc(sizeof(*info->prstatus), GFP_KERNEL);
+	if (!info->prstatus)
+		return 0;
+	info->fpu = kmalloc(sizeof(*info->fpu), GFP_KERNEL);
+	if (!info->fpu)
+		return 0;
+#ifdef ELF_CORE_COPY_XFPREGS
+	info->xfpu = kmalloc(sizeof(*info->xfpu), GFP_KERNEL);
+	if (!info->xfpu)
+		return 0;
+#endif
+	return 1;
+}
+
+static int fill_note_info(struct elfhdr *elf, int phdrs,
+			  struct elf_note_info *info,
+			  const siginfo_t *siginfo, struct pt_regs *regs)
+{
+	struct list_head *t;
+	struct core_thread *ct;
+	struct elf_thread_status *ets;
+
+	if (!elf_note_info_init(info))
+		return 0;
+
+	for (ct = current->mm->core_state->dumper.next;
+					ct; ct = ct->next) {
+		ets = kzalloc(sizeof(*ets), GFP_KERNEL);
+		if (!ets)
+			return 0;
+
+		ets->thread = ct->task;
+		list_add(&ets->list, &info->thread_list);
+	}
+
+	list_for_each(t, &info->thread_list) {
+		int sz;
+
+		ets = list_entry(t, struct elf_thread_status, list);
+		sz = elf_dump_thread_status(siginfo->si_signo, ets);
+		info->thread_status_size += sz;
+	}
+	/* now collect the dump for the current */
+	memset(info->prstatus, 0, sizeof(*info->prstatus));
+	fill_prstatus(info->prstatus, current, siginfo->si_signo);
+	elf_core_copy_regs(&info->prstatus->pr_reg, regs);
+
+	/* Set up header */
+	fill_elf_header(elf, phdrs, ELF_ARCH, ELF_CORE_EFLAGS);
+
+	/*
+	 * Set up the notes in similar form to SVR4 core dumps made
+	 * with info from their /proc.
+	 */
+
+	fill_note(info->notes + 0, "CORE", NT_PRSTATUS,
+		  sizeof(*info->prstatus), info->prstatus);
+	fill_psinfo(info->psinfo, current->group_leader, current->mm);
+	fill_note(info->notes + 1, "CORE", NT_PRPSINFO,
+		  sizeof(*info->psinfo), info->psinfo);
+
+	fill_siginfo_note(info->notes + 2, &info->csigdata, siginfo);
+	fill_auxv_note(info->notes + 3, current->mm);
+	info->numnote = 4;
+
+	if (fill_files_note(info->notes + info->numnote) == 0) {
+		info->notes_files = info->notes + info->numnote;
+		info->numnote++;
+	}
+
+	/* Try to dump the FPU. */
+	info->prstatus->pr_fpvalid = elf_core_copy_task_fpregs(current, regs,
+							       info->fpu);
+	if (info->prstatus->pr_fpvalid)
+		fill_note(info->notes + info->numnote++,
+			  "CORE", NT_PRFPREG, sizeof(*info->fpu), info->fpu);
+#ifdef ELF_CORE_COPY_XFPREGS
+	if (elf_core_copy_task_xfpregs(current, info->xfpu))
+		fill_note(info->notes + info->numnote++,
+			  "LINUX", ELF_CORE_XFPREG_TYPE,
+			  sizeof(*info->xfpu), info->xfpu);
+#endif
+
+	return 1;
+}
+
+static size_t get_note_info_size(struct elf_note_info *info)
+{
+	int sz = 0;
+	int i;
+
+	for (i = 0; i < info->numnote; i++)
+		sz += notesize(info->notes + i);
+
+	sz += info->thread_status_size;
+
+	return sz;
+}
+
+static int write_note_info(struct elf_note_info *info,
+			   struct coredump_params *cprm)
+{
+	int i;
+	struct list_head *t;
+
+	for (i = 0; i < info->numnote; i++)
+		if (!writenote(info->notes + i, cprm))
+			return 0;
+
+	/* write out the thread status notes section */
+	list_for_each(t, &info->thread_list) {
+		struct elf_thread_status *tmp =
+				list_entry(t, struct elf_thread_status, list);
+
+		for (i = 0; i < tmp->num_notes; i++)
+			if (!writenote(&tmp->notes[i], cprm))
+				return 0;
+	}
+
+	return 1;
+}
+
+static void free_note_info(struct elf_note_info *info)
+{
+	while (!list_empty(&info->thread_list)) {
+		struct list_head *tmp = info->thread_list.next;
+		list_del(tmp);
+		kfree(list_entry(tmp, struct elf_thread_status, list));
+	}
+
+	/* Free data possibly allocated by fill_files_note(): */
+	if (info->notes_files)
+		kvfree(info->notes_files->data);
+
+	kfree(info->prstatus);
+	kfree(info->psinfo);
+	kfree(info->notes);
+	kfree(info->fpu);
+#ifdef ELF_CORE_COPY_XFPREGS
+	kfree(info->xfpu);
+#endif
+}
+
+#endif
+
+static struct vm_area_struct *first_vma(struct task_struct *tsk,
+					struct vm_area_struct *gate_vma)
+{
+	struct vm_area_struct *ret = tsk->mm->mmap;
+
+	if (ret)
+		return ret;
+	return gate_vma;
+}
+/*
+ * Helper function for iterating across a vma list.  It ensures that the caller
+ * will visit `gate_vma' prior to terminating the search.
+ */
+static struct vm_area_struct *next_vma(struct vm_area_struct *this_vma,
+					struct vm_area_struct *gate_vma)
+{
+	struct vm_area_struct *ret;
+
+	ret = this_vma->vm_next;
+	if (ret)
+		return ret;
+	if (this_vma == gate_vma)
+		return NULL;
+	return gate_vma;
+}
+
+static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
+			     elf_addr_t e_shoff, int segs)
+{
+	elf->e_shoff = e_shoff;
+	elf->e_shentsize = sizeof(*shdr4extnum);
+	elf->e_shnum = 1;
+	elf->e_shstrndx = SHN_UNDEF;
+
+	memset(shdr4extnum, 0, sizeof(*shdr4extnum));
+
+	shdr4extnum->sh_type = SHT_NULL;
+	shdr4extnum->sh_size = elf->e_shnum;
+	shdr4extnum->sh_link = elf->e_shstrndx;
+	shdr4extnum->sh_info = segs;
+}
+
+/*
+ * Actual dumper
+ *
+ * This is a two-pass process; first we find the offsets of the bits,
+ * and then they are actually written out.  If we run out of core limit
+ * we just truncate.
+ */
+static int elf_core_dump(struct coredump_params *cprm)
+{
+	int has_dumped = 0;
+	mm_segment_t fs;
+	int segs, i;
+	size_t vma_data_size = 0;
+	struct vm_area_struct *vma, *gate_vma;
+	struct elfhdr *elf = NULL;
+	loff_t offset = 0, dataoff;
+	struct elf_note_info info = { };
+	struct elf_phdr *phdr4note = NULL;
+	struct elf_shdr *shdr4extnum = NULL;
+	Elf_Half e_phnum;
+	elf_addr_t e_shoff;
+	elf_addr_t *vma_filesz = NULL;
+
+	/*
+	 * We no longer stop all VM operations.
+	 * 
+	 * This is because those proceses that could possibly change map_count
+	 * or the mmap / vma pages are now blocked in do_exit on current
+	 * finishing this core dump.
+	 *
+	 * Only ptrace can touch these memory addresses, but it doesn't change
+	 * the map_count or the pages allocated. So no possibility of crashing
+	 * exists while dumping the mm->vm_next areas to the core file.
+	 */
+  
+	/* alloc memory for large data structures: too large to be on stack */
+	elf = kmalloc(sizeof(*elf), GFP_KERNEL);
+	if (!elf)
+		goto out;
+	/*
+	 * The number of segs are recored into ELF header as 16bit value.
+	 * Please check DEFAULT_MAX_MAP_COUNT definition when you modify here.
+	 */
+	segs = current->mm->map_count;
+	segs += elf_core_extra_phdrs();
+
+	gate_vma = get_gate_vma(current->mm);
+	if (gate_vma != NULL)
+		segs++;
+
+	/* for notes section */
+	segs++;
+
+	/* If segs > PN_XNUM(0xffff), then e_phnum overflows. To avoid
+	 * this, kernel supports extended numbering. Have a look at
+	 * include/linux/elf.h for further information. */
+	e_phnum = segs > PN_XNUM ? PN_XNUM : segs;
+
+	/*
+	 * Collect all the non-memory information about the process for the
+	 * notes.  This also sets up the file header.
+	 */
+	if (!fill_note_info(elf, e_phnum, &info, cprm->siginfo, cprm->regs))
+		goto cleanup;
+
+	has_dumped = 1;
+
+	fs = get_fs();
+	set_fs(KERNEL_DS);
+
+	offset += sizeof(*elf);				/* Elf header */
+	offset += segs * sizeof(struct elf_phdr);	/* Program headers */
+
+	/* Write notes phdr entry */
+	{
+		size_t sz = get_note_info_size(&info);
+
+		sz += elf_coredump_extra_notes_size();
+
+		phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL);
+		if (!phdr4note)
+			goto end_coredump;
+
+		fill_elf_note_phdr(phdr4note, sz, offset);
+		offset += sz;
+	}
+
+	dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
+
+	if (segs - 1 > ULONG_MAX / sizeof(*vma_filesz))
+		goto end_coredump;
+	vma_filesz = kvmalloc(array_size(sizeof(*vma_filesz), (segs - 1)),
+			      GFP_KERNEL);
+	if (ZERO_OR_NULL_PTR(vma_filesz))
+		goto end_coredump;
+
+	for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;
+			vma = next_vma(vma, gate_vma)) {
+		unsigned long dump_size;
+
+		dump_size = vma_dump_size(vma, cprm->mm_flags);
+		vma_filesz[i++] = dump_size;
+		vma_data_size += dump_size;
+	}
+
+	offset += vma_data_size;
+	offset += elf_core_extra_data_size();
+	e_shoff = offset;
+
+	if (e_phnum == PN_XNUM) {
+		shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL);
+		if (!shdr4extnum)
+			goto end_coredump;
+		fill_extnum_info(elf, shdr4extnum, e_shoff, segs);
+	}
+
+	offset = dataoff;
+
+	if (!dump_emit(cprm, elf, sizeof(*elf)))
+		goto end_coredump;
+
+	if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note)))
+		goto end_coredump;
+
+	/* Write program headers for segments dump */
+	for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;
+			vma = next_vma(vma, gate_vma)) {
+		struct elf_phdr phdr;
+
+		phdr.p_type = PT_LOAD;
+		phdr.p_offset = offset;
+		phdr.p_vaddr = vma->vm_start;
+		phdr.p_paddr = 0;
+		phdr.p_filesz = vma_filesz[i++];
+		phdr.p_memsz = vma->vm_end - vma->vm_start;
+		offset += phdr.p_filesz;
+		phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0;
+		if (vma->vm_flags & VM_WRITE)
+			phdr.p_flags |= PF_W;
+		if (vma->vm_flags & VM_EXEC)
+			phdr.p_flags |= PF_X;
+		phdr.p_align = ELF_EXEC_PAGESIZE;
+
+		if (!dump_emit(cprm, &phdr, sizeof(phdr)))
+			goto end_coredump;
+	}
+
+	if (!elf_core_write_extra_phdrs(cprm, offset))
+		goto end_coredump;
+
+ 	/* write out the notes section */
+	if (!write_note_info(&info, cprm))
+		goto end_coredump;
+
+	if (elf_coredump_extra_notes_write(cprm))
+		goto end_coredump;
+
+	/* Align to page */
+	if (!dump_skip(cprm, dataoff - cprm->pos))
+		goto end_coredump;
+
+	for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;
+			vma = next_vma(vma, gate_vma)) {
+		unsigned long addr;
+		unsigned long end;
+
+		end = vma->vm_start + vma_filesz[i++];
+
+		for (addr = vma->vm_start; addr < end; addr += PAGE_SIZE) {
+			struct page *page;
+			int stop;
+
+			page = get_dump_page(addr);
+			if (page) {
+				void *kaddr = kmap(page);
+				stop = !dump_emit(cprm, kaddr, PAGE_SIZE);
+				kunmap(page);
+				put_page(page);
+			} else
+				stop = !dump_skip(cprm, PAGE_SIZE);
+			if (stop)
+				goto end_coredump;
+		}
+	}
+	dump_truncate(cprm);
+
+	if (!elf_core_write_extra_data(cprm))
+		goto end_coredump;
+
+	if (e_phnum == PN_XNUM) {
+		if (!dump_emit(cprm, shdr4extnum, sizeof(*shdr4extnum)))
+			goto end_coredump;
+	}
+
+end_coredump:
+	set_fs(fs);
+
+cleanup:
+	free_note_info(&info);
+	kfree(shdr4extnum);
+	kvfree(vma_filesz);
+	kfree(phdr4note);
+	kfree(elf);
+out:
+	return has_dumped;
+}
+
+#endif		/* CONFIG_ELF_CORE */
+
+static int __init init_elf_binfmt(void)
+{
+	register_binfmt(&elf_format);
+	return 0;
+}
+
+static void __exit exit_elf_binfmt(void)
+{
+	/* Remove the COFF and ELF loaders. */
+	unregister_binfmt(&elf_format);
+}
+
+core_initcall(init_elf_binfmt);
+module_exit(exit_elf_binfmt);
+MODULE_LICENSE("GPL");