/*
   * linux/fs/binfmt_som.c
   *
   * These are the functions used to load SOM format executables as used
   * by HP-UX.  
   *
   * Copyright 1999 Matthew Wilcox <willy@bofh.ai>
   * based on binfmt_elf which is
   * Copyright 1993, 1994: Eric Youngdale (ericy@cais.com).
   */
  
  #include <linux/module.h>
  
  #include <linux/fs.h>
  #include <linux/stat.h>
  #include <linux/sched.h>
  #include <linux/mm.h>
  #include <linux/mman.h>
  #include <linux/errno.h>
  #include <linux/signal.h>
  #include <linux/binfmts.h>
  #include <linux/som.h>
  #include <linux/string.h>
  #include <linux/file.h>
  #include <linux/fcntl.h>
  #include <linux/ptrace.h>
  #include <linux/slab.h>
  #include <linux/shm.h>
  #include <linux/personality.h>
  #include <linux/init.h>
  
  #include <asm/uaccess.h>
  #include <asm/pgtable.h>
  
  
  #include <linux/elf.h>
  
  static int load_som_binary(struct linux_binprm * bprm);
  static int load_som_library(struct file *);
  
  /*
   * If we don't support core dumping, then supply a NULL so we
   * don't even try.
   */
  #if 0
  static int som_core_dump(struct coredump_params *cprm);
  #else
  #define som_core_dump	NULL
  #endif
  
  #define SOM_PAGESTART(_v) ((_v) & ~(unsigned long)(SOM_PAGESIZE-1))
  #define SOM_PAGEOFFSET(_v) ((_v) & (SOM_PAGESIZE-1))
  #define SOM_PAGEALIGN(_v) (((_v) + SOM_PAGESIZE - 1) & ~(SOM_PAGESIZE - 1))
  
  static struct linux_binfmt som_format = {
  	.module		= THIS_MODULE,
  	.load_binary	= load_som_binary,
  	.load_shlib	= load_som_library,
  	.core_dump	= som_core_dump,
  	.min_coredump	= SOM_PAGESIZE
  };
  
  /*
   * create_som_tables() parses the env- and arg-strings in new user
   * memory and creates the pointer tables from them, and puts their
   * addresses on the "stack", returning the new stack pointer value.
   */
  static void create_som_tables(struct linux_binprm *bprm)
  {
  	char **argv, **envp;
  	int argc = bprm->argc;
  	int envc = bprm->envc;
  	unsigned long p;
  	unsigned long *sp;
  
  	/* Word-align the stack pointer */
  	sp = (unsigned long *)((bprm->p + 3) & ~3);
  
  	envp = (char **) sp;
  	sp += envc + 1;
  	argv = (char **) sp;
  	sp += argc + 1;
  
  	__put_user((unsigned long) envp,++sp);
  	__put_user((unsigned long) argv,++sp);
  
  	__put_user(argc, ++sp);
  
  	bprm->p = (unsigned long) sp;
  
  	p = current->mm->arg_start;
  	while (argc-- > 0) {
  		__put_user((char *)p,argv++);
  		p += strlen_user((char *)p);
  	}
  	__put_user(NULL, argv);
  	current->mm->arg_end = current->mm->env_start = p;
  	while (envc-- > 0) {
  		__put_user((char *)p,envp++);
  		p += strlen_user((char *)p);
  	}
  	__put_user(NULL, envp);
  	current->mm->env_end = p;
  }
  
  static int check_som_header(struct som_hdr *som_ex)
  {
  	int *buf = (int *)som_ex;
  	int i, ck;
  
  	if (som_ex->system_id != SOM_SID_PARISC_1_0 &&
  	    som_ex->system_id != SOM_SID_PARISC_1_1 &&
  	    som_ex->system_id != SOM_SID_PARISC_2_0)
  		return -ENOEXEC;
  
  	if (som_ex->a_magic != SOM_EXEC_NONSHARE &&
  	    som_ex->a_magic != SOM_EXEC_SHARE &&
  	    som_ex->a_magic != SOM_EXEC_DEMAND)
  		return -ENOEXEC;
  
  	if (som_ex->version_id != SOM_ID_OLD &&
  	    som_ex->version_id != SOM_ID_NEW)
  		return -ENOEXEC;
  
  	ck = 0;
  	for (i=0; i<32; i++)
  		ck ^= buf[i];
  	if (ck != 0)
  		return -ENOEXEC;
  
  	return 0;
  }
  
  static int map_som_binary(struct file *file,
  		const struct som_exec_auxhdr *hpuxhdr)
  {
  	unsigned long code_start, code_size, data_start, data_size;
  	unsigned long bss_start, som_brk;
  	int retval;
  	int prot = PROT_READ | PROT_EXEC;
  	int flags = MAP_FIXED|MAP_PRIVATE|MAP_DENYWRITE|MAP_EXECUTABLE;
  
  	mm_segment_t old_fs = get_fs();
  	set_fs(get_ds());
  
  	code_start = SOM_PAGESTART(hpuxhdr->exec_tmem);
  	code_size = SOM_PAGEALIGN(hpuxhdr->exec_tsize);
  	current->mm->start_code = code_start;
  	current->mm->end_code = code_start + code_size;
  	retval = vm_mmap(file, code_start, code_size, prot,
  			flags, SOM_PAGESTART(hpuxhdr->exec_tfile));
  	if (retval < 0 && retval > -1024)
  		goto out;
  
  	data_start = SOM_PAGESTART(hpuxhdr->exec_dmem);
  	data_size = SOM_PAGEALIGN(hpuxhdr->exec_dsize);
  	current->mm->start_data = data_start;
  	current->mm->end_data = bss_start = data_start + data_size;
  	retval = vm_mmap(file, data_start, data_size,
  			prot | PROT_WRITE, flags,
  			SOM_PAGESTART(hpuxhdr->exec_dfile));
  	if (retval < 0 && retval > -1024)
  		goto out;
  
  	som_brk = bss_start + SOM_PAGEALIGN(hpuxhdr->exec_bsize);
  	current->mm->start_brk = current->mm->brk = som_brk;
  	retval = vm_mmap(NULL, bss_start, som_brk - bss_start,
  			prot | PROT_WRITE, MAP_FIXED | MAP_PRIVATE, 0);
  	if (retval > 0 || retval < -1024)
  		retval = 0;
  out:
  	set_fs(old_fs);
  	return retval;
  }
  
  
  /*
   * These are the functions used to load SOM executables and shared
   * libraries.  There is no binary dependent code anywhere else.
   */
  
  static int
  load_som_binary(struct linux_binprm * bprm)
  {
  	int retval;
  	unsigned int size;
  	unsigned long som_entry;
  	struct som_hdr *som_ex;
  	struct som_exec_auxhdr *hpuxhdr;
  	struct pt_regs *regs = current_pt_regs();
  
  	/* Get the exec-header */
  	som_ex = (struct som_hdr *) bprm->buf;
  
  	retval = check_som_header(som_ex);
  	if (retval != 0)
  		goto out;
  
  	/* Now read in the auxiliary header information */
  
  	retval = -ENOMEM;
  	size = som_ex->aux_header_size;
  	if (size > SOM_PAGESIZE)
  		goto out;
  	hpuxhdr = kmalloc(size, GFP_KERNEL);
  	if (!hpuxhdr)
  		goto out;
  
  	retval = kernel_read(bprm->file, som_ex->aux_header_location,
  			(char *) hpuxhdr, size);
  	if (retval != size) {
  		if (retval >= 0)
  			retval = -EIO;
  		goto out_free;
  	}
  
  	/* Flush all traces of the currently running executable */
  	retval = flush_old_exec(bprm);
  	if (retval)
  		goto out_free;
  
  	/* OK, This is the point of no return */
  	current->personality = PER_HPUX;
  	setup_new_exec(bprm);
  
  	/* Set the task size for HP-UX processes such that
  	 * the gateway page is outside the address space.
  	 * This can be fixed later, but for now, this is much
  	 * easier.
  	 */
  
  	current->thread.task_size = 0xc0000000;
  
  	/* Set map base to allow enough room for hp-ux heap growth */
  
  	current->thread.map_base = 0x80000000;
  
  	retval = map_som_binary(bprm->file, hpuxhdr);
  	if (retval < 0)
  		goto out_free;
  
  	som_entry = hpuxhdr->exec_entry;
  	kfree(hpuxhdr);
  
  	set_binfmt(&som_format);
  	install_exec_creds(bprm);
  	setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
  
  	create_som_tables(bprm);
  
  	current->mm->start_stack = bprm->p;
  
  #if 0
  	printk("(start_brk) %08lx
  " , (unsigned long) current->mm->start_brk);
  	printk("(end_code) %08lx
  " , (unsigned long) current->mm->end_code);
  	printk("(start_code) %08lx
  " , (unsigned long) current->mm->start_code);
  	printk("(end_data) %08lx
  " , (unsigned long) current->mm->end_data);
  	printk("(start_stack) %08lx
  " , (unsigned long) current->mm->start_stack);
  	printk("(brk) %08lx
  " , (unsigned long) current->mm->brk);
  #endif
  
  	map_hpux_gateway_page(current,current->mm);
  
  	start_thread_som(regs, som_entry, bprm->p);
  	return 0;
  
  	/* error cleanup */
  out_free:
  	kfree(hpuxhdr);
  out:
  	return retval;
  }
  
  static int load_som_library(struct file *f)
  {
  /* No lib support in SOM yet.  gizza chance.. */
  	return -ENOEXEC;
  }
  	/* Install the SOM loader.
  	 * N.B. We *rely* on the table being the right size with the
  	 * right number of free slots...
  	 */
  
  static int __init init_som_binfmt(void)
  {
  	register_binfmt(&som_format);
  	return 0;
  }
  
  static void __exit exit_som_binfmt(void)
  {
  	/* Remove the SOM loader. */
  	unregister_binfmt(&som_format);
  }
  
  core_initcall(init_som_binfmt);
  module_exit(exit_som_binfmt);
  
  MODULE_LICENSE("GPL");