// SPDX-License-Identifier: GPL-2.0-or-later

  /* binfmt_elf_fdpic.c: FDPIC ELF binary format
   *

   * Copyright (C) 2003, 2004, 2006 Red Hat, Inc. All Rights Reserved.

   * Written by David Howells (dhowells@redhat.com)
   * Derived from binfmt_elf.c

   */
  
  #include <linux/module.h>
  
  #include <linux/fs.h>
  #include <linux/stat.h>
  #include <linux/sched.h>

  #include <linux/sched/coredump.h>
  #include <linux/sched/task_stack.h>

  #include <linux/sched/cputime.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/fcntl.h>
  #include <linux/slab.h>

  #include <linux/pagemap.h>

  #include <linux/security.h>

  #include <linux/highmem.h>

  #include <linux/highuid.h>

  #include <linux/personality.h>
  #include <linux/ptrace.h>
  #include <linux/init.h>

  #include <linux/elf.h>
  #include <linux/elf-fdpic.h>
  #include <linux/elfcore.h>

  #include <linux/coredump.h>

  #include <linux/dax.h>

  #include <linux/regset.h>

  #include <linux/uaccess.h>

  #include <asm/param.h>

  
  typedef char *elf_caddr_t;

  
  #if 0
  #define kdebug(fmt, ...) printk("FDPIC "fmt"
  " ,##__VA_ARGS__ )
  #else
  #define kdebug(fmt, ...) do {} while(0)
  #endif

  #if 0
  #define kdcore(fmt, ...) printk("FDPIC "fmt"
  " ,##__VA_ARGS__ )
  #else
  #define kdcore(fmt, ...) do {} while(0)
  #endif

  MODULE_LICENSE("GPL");

  static int load_elf_fdpic_binary(struct linux_binprm *);

  static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *, struct file *);
  static int elf_fdpic_map_file(struct elf_fdpic_params *, struct file *,
  			      struct mm_struct *, const char *);

  static int create_elf_fdpic_tables(struct linux_binprm *, struct mm_struct *,
  				   struct elf_fdpic_params *,
  				   struct elf_fdpic_params *);

  
  #ifndef CONFIG_MMU

  static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *,
  						   struct file *,
  						   struct mm_struct *);

  #endif

  static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *,
  					     struct file *, struct mm_struct *);

  #ifdef CONFIG_ELF_CORE

  static int elf_fdpic_core_dump(struct coredump_params *cprm);

  #endif

  static struct linux_binfmt elf_fdpic_format = {
  	.module		= THIS_MODULE,
  	.load_binary	= load_elf_fdpic_binary,

  #ifdef CONFIG_ELF_CORE

  	.core_dump	= elf_fdpic_core_dump,
  #endif

  	.min_coredump	= ELF_EXEC_PAGESIZE,
  };

  static int __init init_elf_fdpic_binfmt(void)
  {

  	register_binfmt(&elf_fdpic_format);
  	return 0;

  }

  static void __exit exit_elf_fdpic_binfmt(void)
  {
  	unregister_binfmt(&elf_fdpic_format);
  }

  core_initcall(init_elf_fdpic_binfmt);

  module_exit(exit_elf_fdpic_binfmt);

  static int is_elf(struct elfhdr *hdr, struct file *file)

  {
  	if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0)
  		return 0;
  	if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN)
  		return 0;

  	if (!elf_check_arch(hdr))

  		return 0;

  	if (!file->f_op->mmap)

  		return 0;
  	return 1;
  }

  #ifndef elf_check_fdpic
  #define elf_check_fdpic(x) 0
  #endif
  
  #ifndef elf_check_const_displacement
  #define elf_check_const_displacement(x) 0
  #endif
  
  static int is_constdisp(struct elfhdr *hdr)
  {
  	if (!elf_check_fdpic(hdr))
  		return 1;
  	if (elf_check_const_displacement(hdr))
  		return 1;
  	return 0;
  }

  /*****************************************************************************/
  /*
   * read the program headers table into memory
   */

  static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params,
  				 struct file *file)

  {
  	struct elf32_phdr *phdr;
  	unsigned long size;
  	int retval, loop;

  	loff_t pos = params->hdr.e_phoff;

  
  	if (params->hdr.e_phentsize != sizeof(struct elf_phdr))
  		return -ENOMEM;
  	if (params->hdr.e_phnum > 65536U / sizeof(struct elf_phdr))
  		return -ENOMEM;
  
  	size = params->hdr.e_phnum * sizeof(struct elf_phdr);
  	params->phdrs = kmalloc(size, GFP_KERNEL);
  	if (!params->phdrs)
  		return -ENOMEM;

  	retval = kernel_read(file, params->phdrs, size, &pos);

  	if (unlikely(retval != size))
  		return retval < 0 ? retval : -ENOEXEC;

  
  	/* determine stack size for this binary */
  	phdr = params->phdrs;
  	for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
  		if (phdr->p_type != PT_GNU_STACK)
  			continue;
  
  		if (phdr->p_flags & PF_X)
  			params->flags |= ELF_FDPIC_FLAG_EXEC_STACK;
  		else
  			params->flags |= ELF_FDPIC_FLAG_NOEXEC_STACK;
  
  		params->stack_size = phdr->p_memsz;
  		break;
  	}
  
  	return 0;

  }

  
  /*****************************************************************************/
  /*
   * load an fdpic binary into various bits of memory
   */

  static int load_elf_fdpic_binary(struct linux_binprm *bprm)

  {
  	struct elf_fdpic_params exec_params, interp_params;

  	struct pt_regs *regs = current_pt_regs();

  	struct elf_phdr *phdr;

  	unsigned long stack_size, entryaddr;

  #ifdef ELF_FDPIC_PLAT_INIT
  	unsigned long dynaddr;
  #endif

  #ifndef CONFIG_MMU
  	unsigned long stack_prot;
  #endif

  	struct file *interpreter = NULL; /* to shut gcc up */
  	char *interpreter_name = NULL;
  	int executable_stack;
  	int retval, i;

  	loff_t pos;

  	kdebug("____ LOAD %d ____", current->pid);

  	memset(&exec_params, 0, sizeof(exec_params));
  	memset(&interp_params, 0, sizeof(interp_params));
  
  	exec_params.hdr = *(struct elfhdr *) bprm->buf;
  	exec_params.flags = ELF_FDPIC_FLAG_PRESENT | ELF_FDPIC_FLAG_EXECUTABLE;
  
  	/* check that this is a binary we know how to deal with */
  	retval = -ENOEXEC;

  	if (!is_elf(&exec_params.hdr, bprm->file))

  		goto error;

  	if (!elf_check_fdpic(&exec_params.hdr)) {
  #ifdef CONFIG_MMU
  		/* binfmt_elf handles non-fdpic elf except on nommu */
  		goto error;
  #else
  		/* nommu can only load ET_DYN (PIE) ELF */
  		if (exec_params.hdr.e_type != ET_DYN)
  			goto error;
  #endif
  	}

  
  	/* read the program header table */
  	retval = elf_fdpic_fetch_phdrs(&exec_params, bprm->file);
  	if (retval < 0)
  		goto error;
  
  	/* scan for a program header that specifies an interpreter */
  	phdr = exec_params.phdrs;
  
  	for (i = 0; i < exec_params.hdr.e_phnum; i++, phdr++) {
  		switch (phdr->p_type) {
  		case PT_INTERP:
  			retval = -ENOMEM;
  			if (phdr->p_filesz > PATH_MAX)
  				goto error;
  			retval = -ENOENT;
  			if (phdr->p_filesz < 2)
  				goto error;
  
  			/* read the name of the interpreter into memory */

  			interpreter_name = kmalloc(phdr->p_filesz, GFP_KERNEL);

  			if (!interpreter_name)
  				goto error;

  			pos = phdr->p_offset;
  			retval = kernel_read(bprm->file, interpreter_name,
  					     phdr->p_filesz, &pos);

  			if (unlikely(retval != phdr->p_filesz)) {
  				if (retval >= 0)
  					retval = -ENOEXEC;

  				goto error;

  			}

  
  			retval = -ENOENT;
  			if (interpreter_name[phdr->p_filesz - 1] != '\0')
  				goto error;
  
  			kdebug("Using ELF interpreter %s", interpreter_name);
  
  			/* replace the program with the interpreter */
  			interpreter = open_exec(interpreter_name);
  			retval = PTR_ERR(interpreter);
  			if (IS_ERR(interpreter)) {
  				interpreter = NULL;
  				goto error;
  			}

  			/*
  			 * If the binary is not readable then enforce
  			 * mm->dumpable = 0 regardless of the interpreter's
  			 * permissions.
  			 */

  			would_dump(bprm, interpreter);

  			pos = 0;
  			retval = kernel_read(interpreter, bprm->buf,
  					BINPRM_BUF_SIZE, &pos);

  			if (unlikely(retval != BINPRM_BUF_SIZE)) {
  				if (retval >= 0)
  					retval = -ENOEXEC;

  				goto error;

  			}

  
  			interp_params.hdr = *((struct elfhdr *) bprm->buf);
  			break;
  
  		case PT_LOAD:
  #ifdef CONFIG_MMU
  			if (exec_params.load_addr == 0)
  				exec_params.load_addr = phdr->p_vaddr;
  #endif
  			break;
  		}
  
  	}

  	if (is_constdisp(&exec_params.hdr))

  		exec_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
  
  	/* perform insanity checks on the interpreter */
  	if (interpreter_name) {
  		retval = -ELIBBAD;

  		if (!is_elf(&interp_params.hdr, interpreter))

  			goto error;
  
  		interp_params.flags = ELF_FDPIC_FLAG_PRESENT;
  
  		/* read the interpreter's program header table */
  		retval = elf_fdpic_fetch_phdrs(&interp_params, interpreter);
  		if (retval < 0)
  			goto error;
  	}
  
  	stack_size = exec_params.stack_size;

  	if (exec_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
  		executable_stack = EXSTACK_ENABLE_X;
  	else if (exec_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
  		executable_stack = EXSTACK_DISABLE_X;

  	else
  		executable_stack = EXSTACK_DEFAULT;

  	if (stack_size == 0) {
  		stack_size = interp_params.stack_size;
  		if (interp_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
  			executable_stack = EXSTACK_ENABLE_X;
  		else if (interp_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
  			executable_stack = EXSTACK_DISABLE_X;
  		else
  			executable_stack = EXSTACK_DEFAULT;
  	}

  	retval = -ENOEXEC;
  	if (stack_size == 0)

  		stack_size = 131072UL; /* same as exec.c's default commit */

  	if (is_constdisp(&interp_params.hdr))

  		interp_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;
  
  	/* flush all traces of the currently running executable */

  	retval = begin_new_exec(bprm);

  	if (retval)
  		goto error;
  
  	/* there's now no turning back... the old userspace image is dead,

  	 * defunct, deceased, etc.
  	 */

  	if (elf_check_fdpic(&exec_params.hdr))
  		set_personality(PER_LINUX_FDPIC);
  	else
  		set_personality(PER_LINUX);

  	if (elf_read_implies_exec(&exec_params.hdr, executable_stack))
  		current->personality |= READ_IMPLIES_EXEC;

  
  	setup_new_exec(bprm);

  	set_binfmt(&elf_fdpic_format);
  
  	current->mm->start_code = 0;
  	current->mm->end_code = 0;
  	current->mm->start_stack = 0;
  	current->mm->start_data = 0;
  	current->mm->end_data = 0;
  	current->mm->context.exec_fdpic_loadmap = 0;
  	current->mm->context.interp_fdpic_loadmap = 0;

  #ifdef CONFIG_MMU
  	elf_fdpic_arch_lay_out_mm(&exec_params,
  				  &interp_params,
  				  &current->mm->start_stack,
  				  &current->mm->start_brk);

  	retval = setup_arg_pages(bprm, current->mm->start_stack,
  				 executable_stack);

  	if (retval < 0)
  		goto error;

  #ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
  	retval = arch_setup_additional_pages(bprm, !!interpreter_name);
  	if (retval < 0)
  		goto error;
  #endif

  #endif
  
  	/* load the executable and interpreter into memory */

  	retval = elf_fdpic_map_file(&exec_params, bprm->file, current->mm,
  				    "executable");

  	if (retval < 0)

  		goto error;

  
  	if (interpreter_name) {
  		retval = elf_fdpic_map_file(&interp_params, interpreter,
  					    current->mm, "interpreter");
  		if (retval < 0) {
  			printk(KERN_ERR "Unable to load interpreter
  ");

  			goto error;

  		}
  
  		allow_write_access(interpreter);
  		fput(interpreter);
  		interpreter = NULL;
  	}
  
  #ifdef CONFIG_MMU
  	if (!current->mm->start_brk)
  		current->mm->start_brk = current->mm->end_data;

  	current->mm->brk = current->mm->start_brk =
  		PAGE_ALIGN(current->mm->start_brk);

  
  #else

  	/* create a stack area and zero-size brk area */

  	stack_size = (stack_size + PAGE_SIZE - 1) & PAGE_MASK;
  	if (stack_size < PAGE_SIZE * 2)
  		stack_size = PAGE_SIZE * 2;

  	stack_prot = PROT_READ | PROT_WRITE;
  	if (executable_stack == EXSTACK_ENABLE_X ||
  	    (executable_stack == EXSTACK_DEFAULT && VM_STACK_FLAGS & VM_EXEC))
  		stack_prot |= PROT_EXEC;

  	current->mm->start_brk = vm_mmap(NULL, 0, stack_size, stack_prot,

  					 MAP_PRIVATE | MAP_ANONYMOUS |
  					 MAP_UNINITIALIZED | MAP_GROWSDOWN,

  					 0);

  	if (IS_ERR_VALUE(current->mm->start_brk)) {

  		retval = current->mm->start_brk;
  		current->mm->start_brk = 0;

  		goto error;

  	}

  	current->mm->brk = current->mm->start_brk;
  	current->mm->context.end_brk = current->mm->start_brk;

  	current->mm->start_stack = current->mm->start_brk + stack_size;
  #endif

  	if (create_elf_fdpic_tables(bprm, current->mm,
  				    &exec_params, &interp_params) < 0)

  		goto error;

  	kdebug("- start_code  %lx", current->mm->start_code);
  	kdebug("- end_code    %lx", current->mm->end_code);
  	kdebug("- start_data  %lx", current->mm->start_data);
  	kdebug("- end_data    %lx", current->mm->end_data);
  	kdebug("- start_brk   %lx", current->mm->start_brk);
  	kdebug("- brk         %lx", current->mm->brk);
  	kdebug("- start_stack %lx", current->mm->start_stack);

  
  #ifdef ELF_FDPIC_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.  This macro performs whatever initialization to
  	 * the regs structure is required.
  	 */

  	dynaddr = interp_params.dynamic_addr ?: exec_params.dynamic_addr;
  	ELF_FDPIC_PLAT_INIT(regs, exec_params.map_addr, interp_params.map_addr,
  			    dynaddr);

  #endif

  	finalize_exec(bprm);

  	/* everything is now ready... get the userspace context ready to roll */

  	entryaddr = interp_params.entry_addr ?: exec_params.entry_addr;
  	start_thread(regs, entryaddr, current->mm->start_stack);

  	retval = 0;
  
  error:
  	if (interpreter) {
  		allow_write_access(interpreter);
  		fput(interpreter);
  	}

  	kfree(interpreter_name);
  	kfree(exec_params.phdrs);
  	kfree(exec_params.loadmap);
  	kfree(interp_params.phdrs);
  	kfree(interp_params.loadmap);

  	return retval;

  }

  
  /*****************************************************************************/

  
  #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

  /*

   * present useful information to the program by shovelling it onto the new
   * process's stack

   */
  static int create_elf_fdpic_tables(struct linux_binprm *bprm,
  				   struct mm_struct *mm,
  				   struct elf_fdpic_params *exec_params,
  				   struct elf_fdpic_params *interp_params)
  {

  	const struct cred *cred = current_cred();

  	unsigned long sp, csp, nitems;

  	elf_caddr_t __user *argv, *envp;

  	size_t platform_len = 0, len;

  	char *k_platform, *k_base_platform;
  	char __user *u_platform, *u_base_platform, *p;

  	int loop;

  	int nr;	/* reset for each csp adjustment */

  #ifdef CONFIG_MMU

  	/* 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, so we give the architecture
  	 * an opportunity to do so here.
  	 */
  	sp = arch_align_stack(bprm->p);

  #else
  	sp = mm->start_stack;
  
  	/* stack the program arguments and environment */

  	if (transfer_args_to_stack(bprm, &sp) < 0)

  		return -EFAULT;

  	sp &= ~15;

  #endif

  	/*
  	 * 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.
  	 */

  	k_platform = ELF_PLATFORM;

  	u_platform = NULL;

  
  	if (k_platform) {
  		platform_len = strlen(k_platform) + 1;
  		sp -= platform_len;

  		u_platform = (char __user *) sp;

  		if (copy_to_user(u_platform, k_platform, platform_len) != 0)

  			return -EFAULT;
  	}

  	/*
  	 * If this architecture has a "base" platform capability
  	 * string, copy it to userspace.
  	 */
  	k_base_platform = ELF_BASE_PLATFORM;
  	u_base_platform = NULL;
  
  	if (k_base_platform) {
  		platform_len = strlen(k_base_platform) + 1;
  		sp -= platform_len;
  		u_base_platform = (char __user *) sp;

  		if (copy_to_user(u_base_platform, k_base_platform, platform_len) != 0)

  			return -EFAULT;
  	}

  	sp &= ~7UL;
  
  	/* stack the load map(s) */
  	len = sizeof(struct elf32_fdpic_loadmap);
  	len += sizeof(struct elf32_fdpic_loadseg) * exec_params->loadmap->nsegs;
  	sp = (sp - len) & ~7UL;
  	exec_params->map_addr = sp;

  	if (copy_to_user((void __user *) sp, exec_params->loadmap, len) != 0)

  		return -EFAULT;
  
  	current->mm->context.exec_fdpic_loadmap = (unsigned long) sp;
  
  	if (interp_params->loadmap) {
  		len = sizeof(struct elf32_fdpic_loadmap);

  		len += sizeof(struct elf32_fdpic_loadseg) *
  			interp_params->loadmap->nsegs;

  		sp = (sp - len) & ~7UL;
  		interp_params->map_addr = sp;

  		if (copy_to_user((void __user *) sp, interp_params->loadmap,
  				 len) != 0)

  			return -EFAULT;
  
  		current->mm->context.interp_fdpic_loadmap = (unsigned long) sp;
  	}
  
  	/* force 16 byte _final_ alignment here for generality */

  #define DLINFO_ITEMS 15

  	nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0) +
  		(k_base_platform ? 1 : 0) + AT_VECTOR_SIZE_ARCH;

  	if (bprm->have_execfd)

  		nitems++;

  	csp = sp;
  	sp -= nitems * 2 * sizeof(unsigned long);
  	sp -= (bprm->envc + 1) * sizeof(char *);	/* envv[] */
  	sp -= (bprm->argc + 1) * sizeof(char *);	/* argv[] */
  	sp -= 1 * sizeof(unsigned long);		/* argc */
  
  	csp -= sp & 15UL;
  	sp -= sp & 15UL;
  
  	/* put the ELF interpreter info on the stack */

  #define NEW_AUX_ENT(id, val)						\

  	do {								\

  		struct { unsigned long _id, _val; } __user *ent, v;	\

  									\
  		ent = (void __user *) csp;				\

  		v._id = (id);						\
  		v._val = (val);						\
  		if (copy_to_user(ent + nr, &v, sizeof(v)))		\
  			return -EFAULT;					\

  		nr++;							\

  	} while (0)

  	nr = 0;

  	csp -= 2 * sizeof(unsigned long);

  	NEW_AUX_ENT(AT_NULL, 0);

  	if (k_platform) {

  		nr = 0;

  		csp -= 2 * sizeof(unsigned long);

  		NEW_AUX_ENT(AT_PLATFORM,

  			    (elf_addr_t) (unsigned long) u_platform);

  	}

  	if (k_base_platform) {
  		nr = 0;
  		csp -= 2 * sizeof(unsigned long);
  		NEW_AUX_ENT(AT_BASE_PLATFORM,
  			    (elf_addr_t) (unsigned long) u_base_platform);
  	}

  	if (bprm->have_execfd) {

  		nr = 0;
  		csp -= 2 * sizeof(unsigned long);

  		NEW_AUX_ENT(AT_EXECFD, bprm->execfd);

  	}

  	nr = 0;

  	csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);

  	NEW_AUX_ENT(AT_HWCAP,	ELF_HWCAP);
  #ifdef ELF_HWCAP2
  	NEW_AUX_ENT(AT_HWCAP2,	ELF_HWCAP2);
  #endif

  	NEW_AUX_ENT(AT_PAGESZ,	PAGE_SIZE);
  	NEW_AUX_ENT(AT_CLKTCK,	CLOCKS_PER_SEC);
  	NEW_AUX_ENT(AT_PHDR,	exec_params->ph_addr);
  	NEW_AUX_ENT(AT_PHENT,	sizeof(struct elf_phdr));
  	NEW_AUX_ENT(AT_PHNUM,	exec_params->hdr.e_phnum);
  	NEW_AUX_ENT(AT_BASE,	interp_params->elfhdr_addr);
  	NEW_AUX_ENT(AT_FLAGS,	0);
  	NEW_AUX_ENT(AT_ENTRY,	exec_params->entry_addr);

  	NEW_AUX_ENT(AT_UID,	(elf_addr_t) from_kuid_munged(cred->user_ns, cred->uid));
  	NEW_AUX_ENT(AT_EUID,	(elf_addr_t) from_kuid_munged(cred->user_ns, cred->euid));
  	NEW_AUX_ENT(AT_GID,	(elf_addr_t) from_kgid_munged(cred->user_ns, cred->gid));
  	NEW_AUX_ENT(AT_EGID,	(elf_addr_t) from_kgid_munged(cred->user_ns, cred->egid));

  	NEW_AUX_ENT(AT_SECURE,	bprm->secureexec);

  	NEW_AUX_ENT(AT_EXECFN,	bprm->exec);

  
  #ifdef ARCH_DLINFO

  	nr = 0;
  	csp -= AT_VECTOR_SIZE_ARCH * 2 * sizeof(unsigned long);

  	/* ARCH_DLINFO must come last so platform specific code can enforce
  	 * special alignment requirements on the AUXV if necessary (eg. PPC).
  	 */
  	ARCH_DLINFO;
  #endif
  #undef NEW_AUX_ENT
  
  	/* allocate room for argv[] and envv[] */
  	csp -= (bprm->envc + 1) * sizeof(elf_caddr_t);

  	envp = (elf_caddr_t __user *) csp;

  	csp -= (bprm->argc + 1) * sizeof(elf_caddr_t);

  	argv = (elf_caddr_t __user *) csp;

  
  	/* stack argc */
  	csp -= sizeof(unsigned long);

  	if (put_user(bprm->argc, (unsigned long __user *) csp))
  		return -EFAULT;

  	BUG_ON(csp != sp);

  
  	/* fill in the argv[] array */
  #ifdef CONFIG_MMU
  	current->mm->arg_start = bprm->p;
  #else

  	current->mm->arg_start = current->mm->start_stack -
  		(MAX_ARG_PAGES * PAGE_SIZE - bprm->p);

  #endif

  	p = (char __user *) current->mm->arg_start;

  	for (loop = bprm->argc; loop > 0; loop--) {

  		if (put_user((elf_caddr_t) p, argv++))
  			return -EFAULT;

  		len = strnlen_user(p, MAX_ARG_STRLEN);
  		if (!len || len > MAX_ARG_STRLEN)

  			return -EINVAL;
  		p += len;
  	}

  	if (put_user(NULL, argv))
  		return -EFAULT;

  	current->mm->arg_end = (unsigned long) p;
  
  	/* fill in the envv[] array */
  	current->mm->env_start = (unsigned long) p;
  	for (loop = bprm->envc; loop > 0; loop--) {

  		if (put_user((elf_caddr_t)(unsigned long) p, envp++))
  			return -EFAULT;

  		len = strnlen_user(p, MAX_ARG_STRLEN);
  		if (!len || len > MAX_ARG_STRLEN)

  			return -EINVAL;
  		p += len;
  	}

  	if (put_user(NULL, envp))
  		return -EFAULT;

  	current->mm->env_end = (unsigned long) p;
  
  	mm->start_stack = (unsigned long) sp;
  	return 0;

  }

  
  /*****************************************************************************/

  /*
   * load the appropriate binary image (executable or interpreter) into memory
   * - we assume no MMU is available
   * - if no other PIC bits are set in params->hdr->e_flags
   *   - we assume that the LOADable segments in the binary are independently relocatable
   *   - we assume R/O executable segments are shareable
   * - else
   *   - we assume the loadable parts of the image to require fixed displacement
   *   - the image is not shareable
   */
  static int elf_fdpic_map_file(struct elf_fdpic_params *params,
  			      struct file *file,
  			      struct mm_struct *mm,
  			      const char *what)
  {
  	struct elf32_fdpic_loadmap *loadmap;
  #ifdef CONFIG_MMU
  	struct elf32_fdpic_loadseg *mseg;
  #endif
  	struct elf32_fdpic_loadseg *seg;
  	struct elf32_phdr *phdr;
  	unsigned long load_addr, stop;
  	unsigned nloads, tmp;
  	size_t size;
  	int loop, ret;
  
  	/* allocate a load map table */
  	nloads = 0;
  	for (loop = 0; loop < params->hdr.e_phnum; loop++)
  		if (params->phdrs[loop].p_type == PT_LOAD)
  			nloads++;
  
  	if (nloads == 0)
  		return -ELIBBAD;
  
  	size = sizeof(*loadmap) + nloads * sizeof(*seg);

  	loadmap = kzalloc(size, GFP_KERNEL);

  	if (!loadmap)
  		return -ENOMEM;
  
  	params->loadmap = loadmap;

  
  	loadmap->version = ELF32_FDPIC_LOADMAP_VERSION;
  	loadmap->nsegs = nloads;
  
  	load_addr = params->load_addr;
  	seg = loadmap->segs;
  
  	/* map the requested LOADs into the memory space */
  	switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
  	case ELF_FDPIC_FLAG_CONSTDISP:
  	case ELF_FDPIC_FLAG_CONTIGUOUS:
  #ifndef CONFIG_MMU
  		ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm);
  		if (ret < 0)
  			return ret;
  		break;
  #endif
  	default:
  		ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm);
  		if (ret < 0)
  			return ret;
  		break;
  	}
  
  	/* map the entry point */
  	if (params->hdr.e_entry) {
  		seg = loadmap->segs;
  		for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
  			if (params->hdr.e_entry >= seg->p_vaddr &&

  			    params->hdr.e_entry < seg->p_vaddr + seg->p_memsz) {

  				params->entry_addr =

  					(params->hdr.e_entry - seg->p_vaddr) +
  					seg->addr;

  				break;
  			}
  		}
  	}
  
  	/* determine where the program header table has wound up if mapped */

  	stop = params->hdr.e_phoff;
  	stop += params->hdr.e_phnum * sizeof (struct elf_phdr);

  	phdr = params->phdrs;
  
  	for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
  		if (phdr->p_type != PT_LOAD)
  			continue;
  
  		if (phdr->p_offset > params->hdr.e_phoff ||
  		    phdr->p_offset + phdr->p_filesz < stop)
  			continue;
  
  		seg = loadmap->segs;
  		for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
  			if (phdr->p_vaddr >= seg->p_vaddr &&

  			    phdr->p_vaddr + phdr->p_filesz <=
  			    seg->p_vaddr + seg->p_memsz) {
  				params->ph_addr =
  					(phdr->p_vaddr - seg->p_vaddr) +
  					seg->addr +

  					params->hdr.e_phoff - phdr->p_offset;
  				break;
  			}
  		}
  		break;
  	}
  
  	/* determine where the dynamic section has wound up if there is one */
  	phdr = params->phdrs;
  	for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
  		if (phdr->p_type != PT_DYNAMIC)
  			continue;
  
  		seg = loadmap->segs;
  		for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
  			if (phdr->p_vaddr >= seg->p_vaddr &&

  			    phdr->p_vaddr + phdr->p_memsz <=
  			    seg->p_vaddr + seg->p_memsz) {

  				Elf32_Dyn __user *dyn;
  				Elf32_Sword d_tag;

  				params->dynamic_addr =
  					(phdr->p_vaddr - seg->p_vaddr) +
  					seg->addr;
  
  				/* check the dynamic section contains at least
  				 * one item, and that the last item is a NULL
  				 * entry */

  				if (phdr->p_memsz == 0 ||
  				    phdr->p_memsz % sizeof(Elf32_Dyn) != 0)
  					goto dynamic_error;
  
  				tmp = phdr->p_memsz / sizeof(Elf32_Dyn);

  				dyn = (Elf32_Dyn __user *)params->dynamic_addr;

  				if (get_user(d_tag, &dyn[tmp - 1].d_tag) ||
  				    d_tag != 0)

  					goto dynamic_error;
  				break;
  			}
  		}
  		break;
  	}
  
  	/* now elide adjacent segments in the load map on MMU linux

  	 * - on uClinux the holes between may actually be filled with system
  	 *   stuff or stuff from other processes

  	 */
  #ifdef CONFIG_MMU
  	nloads = loadmap->nsegs;
  	mseg = loadmap->segs;
  	seg = mseg + 1;
  	for (loop = 1; loop < nloads; loop++) {
  		/* see if we have a candidate for merging */
  		if (seg->p_vaddr - mseg->p_vaddr == seg->addr - mseg->addr) {
  			load_addr = PAGE_ALIGN(mseg->addr + mseg->p_memsz);
  			if (load_addr == (seg->addr & PAGE_MASK)) {

  				mseg->p_memsz +=
  					load_addr -
  					(mseg->addr + mseg->p_memsz);

  				mseg->p_memsz += seg->addr & ~PAGE_MASK;
  				mseg->p_memsz += seg->p_memsz;
  				loadmap->nsegs--;
  				continue;
  			}
  		}
  
  		mseg++;
  		if (mseg != seg)
  			*mseg = *seg;
  	}
  #endif
  
  	kdebug("Mapped Object [%s]:", what);
  	kdebug("- elfhdr   : %lx", params->elfhdr_addr);
  	kdebug("- entry    : %lx", params->entry_addr);
  	kdebug("- PHDR[]   : %lx", params->ph_addr);
  	kdebug("- DYNAMIC[]: %lx", params->dynamic_addr);
  	seg = loadmap->segs;
  	for (loop = 0; loop < loadmap->nsegs; loop++, seg++)
  		kdebug("- LOAD[%d] : %08x-%08x [va=%x ms=%x]",
  		       loop,
  		       seg->addr, seg->addr + seg->p_memsz - 1,
  		       seg->p_vaddr, seg->p_memsz);
  
  	return 0;

  dynamic_error:

  	printk("ELF FDPIC %s with invalid DYNAMIC section (inode=%lu)
  ",

  	       what, file_inode(file)->i_ino);

  	return -ELIBBAD;

  }

  
  /*****************************************************************************/
  /*
   * map a file with constant displacement under uClinux
   */
  #ifndef CONFIG_MMU

  static int elf_fdpic_map_file_constdisp_on_uclinux(
  	struct elf_fdpic_params *params,
  	struct file *file,
  	struct mm_struct *mm)

  {
  	struct elf32_fdpic_loadseg *seg;
  	struct elf32_phdr *phdr;
  	unsigned long load_addr, base = ULONG_MAX, top = 0, maddr = 0, mflags;

  	int loop, ret;
  
  	load_addr = params->load_addr;
  	seg = params->loadmap->segs;

  	/* determine the bounds of the contiguous overall allocation we must
  	 * make */

  	phdr = params->phdrs;
  	for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
  		if (params->phdrs[loop].p_type != PT_LOAD)
  			continue;
  
  		if (base > phdr->p_vaddr)
  			base = phdr->p_vaddr;
  		if (top < phdr->p_vaddr + phdr->p_memsz)
  			top = phdr->p_vaddr + phdr->p_memsz;
  	}
  
  	/* allocate one big anon block for everything */
  	mflags = MAP_PRIVATE;
  	if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
  		mflags |= MAP_EXECUTABLE;

  	maddr = vm_mmap(NULL, load_addr, top - base,

  			PROT_READ | PROT_WRITE | PROT_EXEC, mflags, 0);

  	if (IS_ERR_VALUE(maddr))

  		return (int) maddr;
  
  	if (load_addr != 0)
  		load_addr += PAGE_ALIGN(top - base);
  
  	/* and then load the file segments into it */
  	phdr = params->phdrs;
  	for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
  		if (params->phdrs[loop].p_type != PT_LOAD)
  			continue;

  		seg->addr = maddr + (phdr->p_vaddr - base);
  		seg->p_vaddr = phdr->p_vaddr;
  		seg->p_memsz = phdr->p_memsz;

  		ret = read_code(file, seg->addr, phdr->p_offset,
  				       phdr->p_filesz);

  		if (ret < 0)
  			return ret;
  
  		/* map the ELF header address if in this segment */
  		if (phdr->p_offset == 0)
  			params->elfhdr_addr = seg->addr;
  
  		/* clear any space allocated but not loaded */

  		if (phdr->p_filesz < phdr->p_memsz) {

  			if (clear_user((void *) (seg->addr + phdr->p_filesz),
  				       phdr->p_memsz - phdr->p_filesz))
  				return -EFAULT;

  		}

  
  		if (mm) {
  			if (phdr->p_flags & PF_X) {

  				if (!mm->start_code) {
  					mm->start_code = seg->addr;
  					mm->end_code = seg->addr +
  						phdr->p_memsz;
  				}

  			} else if (!mm->start_data) {

  				mm->start_data = seg->addr;

  				mm->end_data = seg->addr + phdr->p_memsz;

  			}

  		}
  
  		seg++;
  	}
  
  	return 0;

  }

  #endif
  
  /*****************************************************************************/
  /*
   * map a binary by direct mmap() of the individual PT_LOAD segments
   */
  static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
  					     struct file *file,
  					     struct mm_struct *mm)
  {
  	struct elf32_fdpic_loadseg *seg;
  	struct elf32_phdr *phdr;
  	unsigned long load_addr, delta_vaddr;

  	int loop, dvset;

  
  	load_addr = params->load_addr;
  	delta_vaddr = 0;
  	dvset = 0;
  
  	seg = params->loadmap->segs;
  
  	/* deal with each load segment separately */
  	phdr = params->phdrs;
  	for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
  		unsigned long maddr, disp, excess, excess1;
  		int prot = 0, flags;
  
  		if (phdr->p_type != PT_LOAD)
  			continue;
  
  		kdebug("[LOAD] va=%lx of=%lx fs=%lx ms=%lx",
  		       (unsigned long) phdr->p_vaddr,
  		       (unsigned long) phdr->p_offset,
  		       (unsigned long) phdr->p_filesz,
  		       (unsigned long) phdr->p_memsz);
  
  		/* determine the mapping parameters */
  		if (phdr->p_flags & PF_R) prot |= PROT_READ;
  		if (phdr->p_flags & PF_W) prot |= PROT_WRITE;
  		if (phdr->p_flags & PF_X) prot |= PROT_EXEC;
  
  		flags = MAP_PRIVATE | MAP_DENYWRITE;
  		if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
  			flags |= MAP_EXECUTABLE;
  
  		maddr = 0;
  
  		switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
  		case ELF_FDPIC_FLAG_INDEPENDENT:
  			/* PT_LOADs are independently locatable */
  			break;
  
  		case ELF_FDPIC_FLAG_HONOURVADDR:
  			/* the specified virtual address must be honoured */
  			maddr = phdr->p_vaddr;
  			flags |= MAP_FIXED;
  			break;
  
  		case ELF_FDPIC_FLAG_CONSTDISP:
  			/* constant displacement

  			 * - can be mapped anywhere, but must be mapped as a
  			 *   unit

  			 */
  			if (!dvset) {
  				maddr = load_addr;
  				delta_vaddr = phdr->p_vaddr;
  				dvset = 1;

  			} else {

  				maddr = load_addr + phdr->p_vaddr - delta_vaddr;
  				flags |= MAP_FIXED;
  			}
  			break;
  
  		case ELF_FDPIC_FLAG_CONTIGUOUS:
  			/* contiguity handled later */
  			break;
  
  		default:
  			BUG();
  		}
  
  		maddr &= PAGE_MASK;
  
  		/* create the mapping */
  		disp = phdr->p_vaddr & ~PAGE_MASK;

  		maddr = vm_mmap(file, maddr, phdr->p_memsz + disp, prot, flags,

  				phdr->p_offset - disp);

  
  		kdebug("mmap[%d] <file> sz=%lx pr=%x fl=%x of=%lx --> %08lx",

  		       loop, phdr->p_memsz + disp, prot, flags,
  		       phdr->p_offset - disp, maddr);

  		if (IS_ERR_VALUE(maddr))

  			return (int) maddr;

  		if ((params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) ==
  		    ELF_FDPIC_FLAG_CONTIGUOUS)

  			load_addr += PAGE_ALIGN(phdr->p_memsz + disp);
  
  		seg->addr = maddr + disp;
  		seg->p_vaddr = phdr->p_vaddr;
  		seg->p_memsz = phdr->p_memsz;
  
  		/* map the ELF header address if in this segment */
  		if (phdr->p_offset == 0)
  			params->elfhdr_addr = seg->addr;

  		/* clear the bit between beginning of mapping and beginning of
  		 * PT_LOAD */

  		if (prot & PROT_WRITE && disp > 0) {
  			kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp);

  			if (clear_user((void __user *) maddr, disp))
  				return -EFAULT;

  			maddr += disp;
  		}
  
  		/* clear any space allocated but not loaded
  		 * - on uClinux we can just clear the lot
  		 * - on MMU linux we'll get a SIGBUS beyond the last page
  		 *   extant in the file
  		 */
  		excess = phdr->p_memsz - phdr->p_filesz;
  		excess1 = PAGE_SIZE - ((maddr + phdr->p_filesz) & ~PAGE_MASK);
  
  #ifdef CONFIG_MMU

  		if (excess > excess1) {
  			unsigned long xaddr = maddr + phdr->p_filesz + excess1;
  			unsigned long xmaddr;
  
  			flags |= MAP_FIXED | MAP_ANONYMOUS;

  			xmaddr = vm_mmap(NULL, xaddr, excess - excess1,

  					 prot, flags, 0);

  
  			kdebug("mmap[%d] <anon>"
  			       " ad=%lx sz=%lx pr=%x fl=%x of=0 --> %08lx",

  			       loop, xaddr, excess - excess1, prot, flags,
  			       xmaddr);

  
  			if (xmaddr != xaddr)
  				return -ENOMEM;
  		}
  
  		if (prot & PROT_WRITE && excess1 > 0) {
  			kdebug("clear[%d] ad=%lx sz=%lx",
  			       loop, maddr + phdr->p_filesz, excess1);

  			if (clear_user((void __user *) maddr + phdr->p_filesz,
  				       excess1))
  				return -EFAULT;

  		}
  
  #else
  		if (excess > 0) {
  			kdebug("clear[%d] ad=%lx sz=%lx",
  			       loop, maddr + phdr->p_filesz, excess);

  			if (clear_user((void *) maddr + phdr->p_filesz, excess))
  				return -EFAULT;

  		}
  #endif
  
  		if (mm) {
  			if (phdr->p_flags & PF_X) {

  				if (!mm->start_code) {
  					mm->start_code = maddr;
  					mm->end_code = maddr + phdr->p_memsz;
  				}

  			} else if (!mm->start_data) {

  				mm->start_data = maddr;
  				mm->end_data = maddr + phdr->p_memsz;
  			}
  		}
  
  		seg++;
  	}
  
  	return 0;

  }

  
  /*****************************************************************************/
  /*
   * ELF-FDPIC core dumper
   *
   * Modelled on fs/exec.c:aout_core_dump()
   * Jeremy Fitzhardinge <jeremy@sw.oz.au>
   *
   * Modelled on fs/binfmt_elf.c core dumper
   */

  #ifdef CONFIG_ELF_CORE

  struct elf_prstatus_fdpic
  {
  	struct elf_siginfo pr_info;	/* Info associated with signal */
  	short	pr_cursig;		/* Current signal */
  	unsigned long pr_sigpend;	/* Set of pending signals */
  	unsigned long pr_sighold;	/* Set of held signals */
  	pid_t	pr_pid;
  	pid_t	pr_ppid;
  	pid_t	pr_pgrp;
  	pid_t	pr_sid;
  	struct __kernel_old_timeval pr_utime;	/* User time */
  	struct __kernel_old_timeval pr_stime;	/* System time */
  	struct __kernel_old_timeval pr_cutime;	/* Cumulative user time */
  	struct __kernel_old_timeval pr_cstime;	/* Cumulative system time */
  	elf_gregset_t pr_reg;	/* GP registers */
  	/* When using FDPIC, the loadmap addresses need to be communicated
  	 * to GDB in order for GDB to do the necessary relocations.  The
  	 * fields (below) used to communicate this information are placed
  	 * immediately after ``pr_reg'', so that the loadmap addresses may
  	 * be viewed as part of the register set if so desired.
  	 */
  	unsigned long pr_exec_fdpic_loadmap;
  	unsigned long pr_interp_fdpic_loadmap;
  	int pr_fpvalid;		/* True if math co-processor being used.  */
  };

  /* 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;
  }
  
  /* #define DEBUG */

  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 inline void fill_elf_fdpic_header(struct elfhdr *elf, int segs)
  {
  	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;
  	memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
  
  	elf->e_type = ET_CORE;
  	elf->e_machine = ELF_ARCH;
  	elf->e_version = EV_CURRENT;
  	elf->e_entry = 0;
  	elf->e_phoff = sizeof(struct elfhdr);
  	elf->e_shoff = 0;
  	elf->e_flags = ELF_FDPIC_CORE_EFLAGS;
  	elf->e_ehsize = sizeof(struct elfhdr);
  	elf->e_phentsize = sizeof(struct elf_phdr);
  	elf->e_phnum = segs;
  	elf->e_shentsize = 0;
  	elf->e_shnum = 0;
  	elf->e_shstrndx = 0;
  	return;
  }
  
  static inline 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 inline 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_fdpic *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_kernel_old_timeval(cputime.utime);
  		prstatus->pr_stime = ns_to_kernel_old_timeval(cputime.stime);

  	} else {

  		u64 utime, stime;

  		task_cputime(p, &utime, &stime);

  		prstatus->pr_utime = ns_to_kernel_old_timeval(utime);
  		prstatus->pr_stime = ns_to_kernel_old_timeval(stime);

  	}

  	prstatus->pr_cutime = ns_to_kernel_old_timeval(p->signal->cutime);
  	prstatus->pr_cstime = ns_to_kernel_old_timeval(p->signal->cstime);

  
  	prstatus->pr_exec_fdpic_loadmap = p->mm->context.exec_fdpic_loadmap;
  	prstatus->pr_interp_fdpic_loadmap = p->mm->context.interp_fdpic_loadmap;
  }
  
  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;
  }
  
  /* Here is the structure in which status of each thread is captured. */
  struct elf_thread_status
  {

  	struct elf_thread_status *next;

  	struct elf_prstatus_fdpic prstatus;	/* NT_PRSTATUS */

  	elf_fpregset_t fpu;		/* NT_PRFPREG */

  	struct memelfnote notes[2];

  	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 thread's pr_status and then create
   * a single section for them in the final core file.
   */

  static struct elf_thread_status *elf_dump_thread_status(long signr, struct task_struct *p, int *sz)

  {

  	const struct user_regset_view *view = task_user_regset_view(p);

  	struct elf_thread_status *t;

  	int i, ret;

  	t = kzalloc(sizeof(struct elf_thread_status), GFP_KERNEL);
  	if (!t)
  		return t;

  
  	fill_prstatus(&t->prstatus, p, signr);

  	regset_get(p, &view->regsets[0],
  		   sizeof(t->prstatus.pr_reg), &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]);

  	for (i = 1; i < view->n; ++i) {
  		const struct user_regset *regset = &view->regsets[i];
  		if (regset->core_note_type != NT_PRFPREG)
  			continue;
  		if (regset->active && regset->active(p, regset) <= 0)
  			continue;
  		ret = regset_get(p, regset, sizeof(t->fpu), &t->fpu);
  		if (ret >= 0)
  			t->prstatus.pr_fpvalid = 1;
  		break;
  	}

  	if (t->prstatus.pr_fpvalid) {
  		fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu),
  			  &t->fpu);
  		t->num_notes++;

  		*sz += notesize(&t->notes[1]);

  	}

  	return t;

  }

  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;
  }

  /*
   * dump the segments for an MMU process
   */

  static bool elf_fdpic_dump_segments(struct coredump_params *cprm,
  				    struct core_vma_metadata *vma_meta,
  				    int vma_count)

  {

  	int i;

  	for (i = 0; i < vma_count; i++) {
  		struct core_vma_metadata *meta = vma_meta + i;

  		if (!dump_user_range(cprm, meta->start, meta->dump_size))

  			return false;

  	}

  	return true;

  }

  
  /*
   * 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_fdpic_core_dump(struct coredump_params *cprm)

  {

  	int has_dumped = 0;

  	int vma_count, segs;

  	int i;

  	struct elfhdr *elf = NULL;

  	loff_t offset = 0, dataoff;

  	struct memelfnote psinfo_note, auxv_note;

  	struct elf_prpsinfo *psinfo = NULL;	/* NT_PRPSINFO */

  	struct elf_thread_status *thread_list = NULL;

  	int thread_status_size = 0;

  	elf_addr_t *auxv;

  	struct elf_phdr *phdr4note = NULL;

  	struct elf_shdr *shdr4extnum = NULL;
  	Elf_Half e_phnum;
  	elf_addr_t e_shoff;

  	struct core_thread *ct;
  	struct elf_thread_status *tmp;

  	struct core_vma_metadata *vma_meta = NULL;
  	size_t vma_data_size;

  
  	/* alloc memory for large data structures: too large to be on stack */
  	elf = kmalloc(sizeof(*elf), GFP_KERNEL);
  	if (!elf)

  		goto end_coredump;

  	psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
  	if (!psinfo)

  		goto end_coredump;

  	if (dump_vma_snapshot(cprm, &vma_count, &vma_meta, &vma_data_size))
  		goto end_coredump;

  	for (ct = current->mm->core_state->dumper.next;
  					ct; ct = ct->next) {

  		tmp = elf_dump_thread_status(cprm->siginfo->si_signo,
  					     ct->task, &thread_status_size);

  		if (!tmp)

  			goto end_coredump;

  		tmp->next = thread_list;
  		thread_list = tmp;

  	}
  
  	/* now collect the dump for the current */

  	tmp = elf_dump_thread_status(cprm->siginfo->si_signo,
  				     current, &thread_status_size);
  	if (!tmp)
  		goto end_coredump;
  	tmp->next = thread_list;
  	thread_list = tmp;

  	segs = vma_count + elf_core_extra_phdrs();

  	/* 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;

  	/* Set up header */

  	fill_elf_fdpic_header(elf, e_phnum);

  
  	has_dumped = 1;

  	/*
  	 * Set up the notes in similar form to SVR4 core dumps made
  	 * with info from their /proc.
  	 */

  	fill_psinfo(psinfo, current->group_leader, current->mm);

  	fill_note(&psinfo_note, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
  	thread_status_size += notesize(&psinfo_note);

  
  	auxv = (elf_addr_t *) current->mm->saved_auxv;

  	i = 0;
  	do
  		i += 2;
  	while (auxv[i - 2] != AT_NULL);

  	fill_note(&auxv_note, "CORE", NT_AUXV, i * sizeof(elf_addr_t), auxv);
  	thread_status_size += notesize(&auxv_note);

  	offset = sizeof(*elf);				/* Elf header */

  	offset += segs * sizeof(struct elf_phdr);	/* Program headers */

  
  	/* Write notes phdr entry */

  	phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL);
  	if (!phdr4note)
  		goto end_coredump;

  	fill_elf_note_phdr(phdr4note, thread_status_size, offset);
  	offset += thread_status_size;

  
  	/* Page-align dumped data */
  	dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);

  	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; i < vma_count; i++) {
  		struct core_vma_metadata *meta = vma_meta + i;

  		struct elf_phdr phdr;
  		size_t sz;

  		sz = meta->end - meta->start;

  
  		phdr.p_type = PT_LOAD;
  		phdr.p_offset = offset;

  		phdr.p_vaddr = meta->start;

  		phdr.p_paddr = 0;

  		phdr.p_filesz = meta->dump_size;

  		phdr.p_memsz = sz;
  		offset += phdr.p_filesz;

  		phdr.p_flags = 0;
  		if (meta->flags & VM_READ)
  			phdr.p_flags |= PF_R;
  		if (meta->flags & VM_WRITE)

  			phdr.p_flags |= PF_W;

  		if (meta->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 (!writenote(thread_list->notes, cprm))
  		goto end_coredump;
  	if (!writenote(&psinfo_note, cprm))
  		goto end_coredump;
  	if (!writenote(&auxv_note, cprm))
  		goto end_coredump;
  	for (i = 1; i < thread_list->num_notes; i++)
  		if (!writenote(thread_list->notes + i, cprm))

  			goto end_coredump;
  
  	/* write out the thread status notes section */

  	for (tmp = thread_list->next; tmp; tmp = tmp->next) {

  		for (i = 0; i < tmp->num_notes; i++)

  			if (!writenote(&tmp->notes[i], cprm))

  				goto end_coredump;
  	}

  	if (!dump_skip(cprm, dataoff - cprm->pos))

  		goto end_coredump;

  	if (!elf_fdpic_dump_segments(cprm, vma_meta, vma_count))

  		goto end_coredump;

  	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;
  	}

  	if (cprm->file->f_pos != offset) {

  		/* Sanity check */
  		printk(KERN_WARNING
  		       "elf_core_dump: file->f_pos (%lld) != offset (%lld)
  ",

  		       cprm->file->f_pos, offset);

  	}
  
  end_coredump:

  	while (thread_list) {
  		tmp = thread_list;
  		thread_list = thread_list->next;
  		kfree(tmp);

  	}

  	kvfree(vma_meta);

  	kfree(phdr4note);

  	kfree(elf);

  	kfree(psinfo);

  	kfree(shdr4extnum);

  	return has_dumped;

  }

  #endif		/* CONFIG_ELF_CORE */