Committer: Michael Beasley <mike@snafu.setup>

[mikesnafu-overlay.git] / arch / mips / kernel / irixelf.c

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * irixelf.c: Code to load IRIX ELF executables conforming to the MIPS ABI.
 *            Based off of work by Eric Youngdale.
 *
 * Copyright (C) 1993 - 1994 Eric Youngdale <ericy@cais.com>
 * Copyright (C) 1996 - 2004 David S. Miller <dm@engr.sgi.com>
 * Copyright (C) 2004 - 2005 Steven J. Hill <sjhill@realitydiluted.com>
 */
#undef DEBUG

#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/a.out.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/signal.h>
#include <linux/binfmts.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/elfcore.h>

#include <asm/mipsregs.h>
#include <asm/namei.h>
#include <asm/prctl.h>
#include <asm/uaccess.h>

#define DLINFO_ITEMS 12

#include <linux/elf.h>

static int load_irix_binary(struct linux_binprm * bprm, struct pt_regs * regs);
static int load_irix_library(struct file *);
static int irix_core_dump(long signr, struct pt_regs * regs,
                          struct file *file, unsigned long limit);

static struct linux_binfmt irix_format = {
        .module         = THIS_MODULE,
        .load_binary    = load_irix_binary,
        .load_shlib     = load_irix_library,
        .core_dump      = irix_core_dump,
        .min_coredump   = PAGE_SIZE,
};

/* Debugging routines. */
static char *get_elf_p_type(Elf32_Word p_type)
{
#ifdef DEBUG
        switch (p_type) {
        case PT_NULL:
                return "PT_NULL";
                break;

        case PT_LOAD:
                return "PT_LOAD";
                break;

        case PT_DYNAMIC:
                return "PT_DYNAMIC";
                break;

        case PT_INTERP:
                return "PT_INTERP";
                break;

        case PT_NOTE:
                return "PT_NOTE";
                break;

        case PT_SHLIB:
                return "PT_SHLIB";
                break;

        case PT_PHDR:
                return "PT_PHDR";
                break;

        case PT_LOPROC:
                return "PT_LOPROC/REGINFO";
                break;

        case PT_HIPROC:
                return "PT_HIPROC";
                break;

        default:
                return "PT_BOGUS";
                break;
        }
#endif
}

static void print_elfhdr(struct elfhdr *ehp)
{
        int i;

        pr_debug("ELFHDR: e_ident<");
        for (i = 0; i < (EI_NIDENT - 1); i++)
                pr_debug("%x ", ehp->e_ident[i]);
        pr_debug("%x>\n", ehp->e_ident[i]);
        pr_debug("        e_type[%04x] e_machine[%04x] e_version[%08lx]\n",
                 (unsigned short) ehp->e_type, (unsigned short) ehp->e_machine,
                 (unsigned long) ehp->e_version);
        pr_debug("        e_entry[%08lx] e_phoff[%08lx] e_shoff[%08lx] "
                 "e_flags[%08lx]\n",
                 (unsigned long) ehp->e_entry, (unsigned long) ehp->e_phoff,
                 (unsigned long) ehp->e_shoff, (unsigned long) ehp->e_flags);
        pr_debug("        e_ehsize[%04x] e_phentsize[%04x] e_phnum[%04x]\n",
                 (unsigned short) ehp->e_ehsize,
                 (unsigned short) ehp->e_phentsize,
                 (unsigned short) ehp->e_phnum);
        pr_debug("        e_shentsize[%04x] e_shnum[%04x] e_shstrndx[%04x]\n",
                 (unsigned short) ehp->e_shentsize,
                 (unsigned short) ehp->e_shnum,
                 (unsigned short) ehp->e_shstrndx);
}

static void print_phdr(int i, struct elf_phdr *ep)
{
        pr_debug("PHDR[%d]: p_type[%s] p_offset[%08lx] p_vaddr[%08lx] "
                 "p_paddr[%08lx]\n", i, get_elf_p_type(ep->p_type),
                 (unsigned long) ep->p_offset, (unsigned long) ep->p_vaddr,
                 (unsigned long) ep->p_paddr);
        pr_debug("         p_filesz[%08lx] p_memsz[%08lx] p_flags[%08lx] "
                 "p_align[%08lx]\n", (unsigned long) ep->p_filesz,
                 (unsigned long) ep->p_memsz, (unsigned long) ep->p_flags,
                 (unsigned long) ep->p_align);
}

static void dump_phdrs(struct elf_phdr *ep, int pnum)
{
        int i;

        for (i = 0; i < pnum; i++, ep++) {
                if ((ep->p_type == PT_LOAD) ||
                    (ep->p_type == PT_INTERP) ||
                    (ep->p_type == PT_PHDR))
                        print_phdr(i, ep);
        }
}

static void set_brk(unsigned long start, unsigned long end)
{
        start = PAGE_ALIGN(start);
        end = PAGE_ALIGN(end);
        if (end <= start)
                return;
        down_write(&current->mm->mmap_sem);
        do_brk(start, end - start);
        up_write(&current->mm->mmap_sem);
}


/* 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 void padzero(unsigned long elf_bss)
{
        unsigned long nbyte;

        nbyte = elf_bss & (PAGE_SIZE-1);
        if (nbyte) {
                nbyte = PAGE_SIZE - nbyte;
                clear_user((void __user *) elf_bss, nbyte);
        }
}

static unsigned long * create_irix_tables(char * p, int argc, int envc,
        struct elfhdr * exec, unsigned int load_addr,
        unsigned int interp_load_addr, struct pt_regs *regs,
        struct elf_phdr *ephdr)
{
        elf_addr_t *argv;
        elf_addr_t *envp;
        elf_addr_t *sp, *csp;

        pr_debug("create_irix_tables: p[%p] argc[%d] envc[%d] "
                 "load_addr[%08x] interp_load_addr[%08x]\n",
                 p, argc, envc, load_addr, interp_load_addr);

        sp = (elf_addr_t *) (~15UL & (unsigned long) p);
        csp = sp;
        csp -= exec ? DLINFO_ITEMS*2 : 2;
        csp -= envc+1;
        csp -= argc+1;
        csp -= 1;               /* argc itself */
        if ((unsigned long)csp & 15UL) {
                sp -= (16UL - ((unsigned long)csp & 15UL)) / sizeof(*sp);
        }

        /*
         * Put the ELF interpreter info on the stack
         */
#define NEW_AUX_ENT(nr, id, val) \
          __put_user((id), sp+(nr*2)); \
          __put_user((val), sp+(nr*2+1)); \

        sp -= 2;
        NEW_AUX_ENT(0, AT_NULL, 0);

        if (exec) {
                sp -= 11*2;

                NEW_AUX_ENT(0, AT_PHDR, load_addr + exec->e_phoff);
                NEW_AUX_ENT(1, AT_PHENT, sizeof(struct elf_phdr));
                NEW_AUX_ENT(2, AT_PHNUM, exec->e_phnum);
                NEW_AUX_ENT(3, AT_PAGESZ, ELF_EXEC_PAGESIZE);
                NEW_AUX_ENT(4, AT_BASE, interp_load_addr);
                NEW_AUX_ENT(5, AT_FLAGS, 0);
                NEW_AUX_ENT(6, AT_ENTRY, (elf_addr_t) exec->e_entry);
                NEW_AUX_ENT(7, AT_UID, (elf_addr_t) current->uid);
                NEW_AUX_ENT(8, AT_EUID, (elf_addr_t) current->euid);
                NEW_AUX_ENT(9, AT_GID, (elf_addr_t) current->gid);
                NEW_AUX_ENT(10, AT_EGID, (elf_addr_t) current->egid);
        }
#undef NEW_AUX_ENT

        sp -= envc+1;
        envp = sp;
        sp -= argc+1;
        argv = sp;

        __put_user((elf_addr_t)argc, --sp);
        current->mm->arg_start = (unsigned long) p;
        while (argc-->0) {
                __put_user((unsigned long)p, argv++);
                p += strlen_user(p);
        }
        __put_user((unsigned long) NULL, argv);
        current->mm->arg_end = current->mm->env_start = (unsigned long) p;
        while (envc-->0) {
                __put_user((unsigned long)p, envp++);
                p += strlen_user(p);
        }
        __put_user((unsigned long) NULL, envp);
        current->mm->env_end = (unsigned long) p;
        return sp;
}


/* 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 int load_irix_interp(struct elfhdr * interp_elf_ex,
                                     struct file * interpreter,
                                     unsigned int *interp_load_addr)
{
        struct elf_phdr *elf_phdata  =  NULL;
        struct elf_phdr *eppnt;
        unsigned int len;
        unsigned int load_addr;
        int elf_bss;
        int retval;
        unsigned int last_bss;
        int error;
        int i;
        unsigned int k;

        elf_bss = 0;
        last_bss = 0;
        error = load_addr = 0;

        print_elfhdr(interp_elf_ex);

        /* First of all, some simple consistency checks */
        if ((interp_elf_ex->e_type != ET_EXEC &&
             interp_elf_ex->e_type != ET_DYN) ||
             !interpreter->f_op->mmap) {
                printk("IRIX interp has bad e_type %d\n", interp_elf_ex->e_type);
                return 0xffffffff;
        }

        /* Now read in all of the header information */
        if (sizeof(struct elf_phdr) * interp_elf_ex->e_phnum > PAGE_SIZE) {
            printk("IRIX interp header bigger than a page (%d)\n",
                   (sizeof(struct elf_phdr) * interp_elf_ex->e_phnum));
            return 0xffffffff;
        }

        elf_phdata = kmalloc(sizeof(struct elf_phdr) * interp_elf_ex->e_phnum,
                             GFP_KERNEL);

        if (!elf_phdata) {
                printk("Cannot kmalloc phdata for IRIX interp.\n");
                return 0xffffffff;
        }

        /* If the size of this structure has changed, then punt, since
         * we will be doing the wrong thing.
         */
        if (interp_elf_ex->e_phentsize != 32) {
                printk("IRIX interp e_phentsize == %d != 32 ",
                       interp_elf_ex->e_phentsize);
                kfree(elf_phdata);
                return 0xffffffff;
        }

        retval = kernel_read(interpreter, interp_elf_ex->e_phoff,
                           (char *) elf_phdata,
                           sizeof(struct elf_phdr) * interp_elf_ex->e_phnum);

        dump_phdrs(elf_phdata, interp_elf_ex->e_phnum);

        eppnt = 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;
                        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;
                        elf_type |= MAP_FIXED;
                        vaddr = eppnt->p_vaddr;

                        pr_debug("INTERP do_mmap"
                                 "(%p, %08lx, %08lx, %08lx, %08lx, %08lx) ",
                                 interpreter, vaddr,
                                 (unsigned long)
                                 (eppnt->p_filesz + (eppnt->p_vaddr & 0xfff)),
                                 (unsigned long)
                                 elf_prot, (unsigned long) elf_type,
                                 (unsigned long)
                                 (eppnt->p_offset & 0xfffff000));

                        down_write(&current->mm->mmap_sem);
                        error = do_mmap(interpreter, vaddr,
                        eppnt->p_filesz + (eppnt->p_vaddr & 0xfff),
                        elf_prot, elf_type,
                        eppnt->p_offset & 0xfffff000);
                        up_write(&current->mm->mmap_sem);

                        if (error < 0 && error > -1024) {
                                printk("Aieee IRIX interp mmap error=%d\n",
                                       error);
                                break;  /* Real error */
                        }
                        pr_debug("error=%08lx ", (unsigned long) error);
                        if (!load_addr && interp_elf_ex->e_type == ET_DYN) {
                                load_addr = error;
                                pr_debug("load_addr = error ");
                        }

                        /*
                         * Find the end of the file  mapping for this phdr, and
                         * keep track of the largest address we see for this.
                         */
                        k = 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 = eppnt->p_memsz + eppnt->p_vaddr;
                        if (k > last_bss)
                                last_bss = k;
                        pr_debug("\n");
                }
        }

        /* Now use mmap to map the library into memory. */
        if (error < 0 && error > -1024) {
                pr_debug("got error %d\n", error);
                kfree(elf_phdata);
                return 0xffffffff;
        }

        /* Now fill out the bss section.  First pad the last page up
         * to the page boundary, and then perform a mmap to make sure
         * that there are zero-mapped pages up to and including the
         * last bss page.
         */
        pr_debug("padzero(%08lx) ", (unsigned long) (elf_bss));
        padzero(elf_bss);
        len = (elf_bss + 0xfff) & 0xfffff000; /* What we have mapped so far */

        pr_debug("last_bss[%08lx] len[%08lx]\n", (unsigned long) last_bss,
                 (unsigned long) len);

        /* Map the last of the bss segment */
        if (last_bss > len) {
                down_write(&current->mm->mmap_sem);
                do_brk(len, (last_bss - len));
                up_write(&current->mm->mmap_sem);
        }
        kfree(elf_phdata);

        *interp_load_addr = load_addr;
        return ((unsigned int) interp_elf_ex->e_entry);
}

/* Check sanity of IRIX elf executable header. */
static int verify_binary(struct elfhdr *ehp, struct linux_binprm *bprm)
{
        if (memcmp(ehp->e_ident, ELFMAG, SELFMAG) != 0)
                return -ENOEXEC;

        /* First of all, some simple consistency checks */
        if ((ehp->e_type != ET_EXEC && ehp->e_type != ET_DYN) ||
            !bprm->file->f_op->mmap) {
                return -ENOEXEC;
        }

        /* XXX Don't support N32 or 64bit binaries yet because they can
         * XXX and do execute 64 bit instructions and expect all registers
         * XXX to be 64 bit as well.  We need to make the kernel save
         * XXX all registers as 64bits on cpu's capable of this at
         * XXX exception time plus frob the XTLB exception vector.
         */
        if ((ehp->e_flags & EF_MIPS_ABI2))
                return -ENOEXEC;

        return 0;
}

/*
 * This is where the detailed check is performed. Irix binaries
 * use interpreters with 'libc.so' in the name, so this function
 * can differentiate between Linux and Irix binaries.
 */
static inline int look_for_irix_interpreter(char **name,
                                            struct file **interpreter,
                                            struct elfhdr *interp_elf_ex,
                                            struct elf_phdr *epp,
                                            struct linux_binprm *bprm, int pnum)
{
        int i;
        int retval = -EINVAL;
        struct file *file = NULL;

        *name = NULL;
        for (i = 0; i < pnum; i++, epp++) {
                if (epp->p_type != PT_INTERP)
                        continue;

                /* It is illegal to have two interpreters for one executable. */
                if (*name != NULL)
                        goto out;

                *name = kmalloc(epp->p_filesz + strlen(IRIX_EMUL), GFP_KERNEL);
                if (!*name)
                        return -ENOMEM;

                strcpy(*name, IRIX_EMUL);
                retval = kernel_read(bprm->file, epp->p_offset, (*name + 16),
                                     epp->p_filesz);
                if (retval < 0)
                        goto out;

                file = open_exec(*name);
                if (IS_ERR(file)) {
                        retval = PTR_ERR(file);
                        goto out;
                }
                retval = kernel_read(file, 0, bprm->buf, 128);
                if (retval < 0)
                        goto dput_and_out;

                *interp_elf_ex = *(struct elfhdr *) bprm->buf;
        }
        *interpreter = file;
        return 0;

dput_and_out:
        fput(file);
out:
        kfree(*name);
        return retval;
}

static inline int verify_irix_interpreter(struct elfhdr *ihp)
{
        if (memcmp(ihp->e_ident, ELFMAG, SELFMAG) != 0)
                return -ELIBBAD;
        return 0;
}

#define EXEC_MAP_FLAGS (MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE)

static inline void map_executable(struct file *fp, struct elf_phdr *epp, int pnum,
                                  unsigned int *estack, unsigned int *laddr,
                                  unsigned int *scode, unsigned int *ebss,
                                  unsigned int *ecode, unsigned int *edata,
                                  unsigned int *ebrk)
{
        unsigned int tmp;
        int i, prot;

        for (i = 0; i < pnum; i++, epp++) {
                if (epp->p_type != PT_LOAD)
                        continue;

                /* Map it. */
                prot  = (epp->p_flags & PF_R) ? PROT_READ : 0;
                prot |= (epp->p_flags & PF_W) ? PROT_WRITE : 0;
                prot |= (epp->p_flags & PF_X) ? PROT_EXEC : 0;
                down_write(&current->mm->mmap_sem);
                (void) do_mmap(fp, (epp->p_vaddr & 0xfffff000),
                               (epp->p_filesz + (epp->p_vaddr & 0xfff)),
                               prot, EXEC_MAP_FLAGS,
                               (epp->p_offset & 0xfffff000));
                up_write(&current->mm->mmap_sem);

                /* Fixup location tracking vars. */
                if ((epp->p_vaddr & 0xfffff000) < *estack)
                        *estack = (epp->p_vaddr & 0xfffff000);
                if (!*laddr)
                        *laddr = epp->p_vaddr - epp->p_offset;
                if (epp->p_vaddr < *scode)
                        *scode = epp->p_vaddr;

                tmp = epp->p_vaddr + epp->p_filesz;
                if (tmp > *ebss)
                        *ebss = tmp;
                if ((epp->p_flags & PF_X) && *ecode < tmp)
                        *ecode = tmp;
                if (*edata < tmp)
                        *edata = tmp;

                tmp = epp->p_vaddr + epp->p_memsz;
                if (tmp > *ebrk)
                        *ebrk = tmp;
        }

}

static inline int map_interpreter(struct elf_phdr *epp, struct elfhdr *ihp,
                                  struct file *interp, unsigned int *iladdr,
                                  int pnum, mm_segment_t old_fs,
                                  unsigned int *eentry)
{
        int i;

        *eentry = 0xffffffff;
        for (i = 0; i < pnum; i++, epp++) {
                if (epp->p_type != PT_INTERP)
                        continue;

                /* We should have fielded this error elsewhere... */
                if (*eentry != 0xffffffff)
                        return -1;

                set_fs(old_fs);
                *eentry = load_irix_interp(ihp, interp, iladdr);
                old_fs = get_fs();
                set_fs(get_ds());

                fput(interp);

                if (*eentry == 0xffffffff)
                        return -1;
        }
        return 0;
}

/*
 * IRIX maps a page at 0x200000 that holds information about the
 * process and the system, here we map the page and fill the
 * structure
 */
static void irix_map_prda_page(void)
{
        unsigned long v;
        struct prda *pp;

        down_write(&current->mm->mmap_sem);
        v =  do_brk(PRDA_ADDRESS, PAGE_SIZE);
        up_write(&current->mm->mmap_sem);

        if (v < 0)
                return;

        pp = (struct prda *) v;
        pp->prda_sys.t_pid  = task_pid_vnr(current);
        pp->prda_sys.t_prid = read_c0_prid();
        pp->prda_sys.t_rpid = task_pid_vnr(current);

        /* We leave the rest set to zero */
}



/* These are the functions used to load ELF style executables and shared
 * libraries.  There is no binary dependent code anywhere else.
 */
static int load_irix_binary(struct linux_binprm * bprm, struct pt_regs * regs)
{
        struct elfhdr elf_ex, interp_elf_ex;
        struct file *interpreter;
        struct elf_phdr *elf_phdata, *elf_ihdr, *elf_ephdr;
        unsigned int load_addr, elf_bss, elf_brk;
        unsigned int elf_entry, interp_load_addr = 0;
        unsigned int start_code, end_code, end_data, elf_stack;
        int retval, has_interp, has_ephdr, size, i;
        char *elf_interpreter;
        mm_segment_t old_fs;

        load_addr = 0;
        has_interp = has_ephdr = 0;
        elf_ihdr = elf_ephdr = NULL;
        elf_ex = *((struct elfhdr *) bprm->buf);
        retval = -ENOEXEC;

        if (verify_binary(&elf_ex, bprm))
                goto out;

        /*
         * Telling -o32 static binaries from Linux and Irix apart from each
         * other is difficult. There are 2 differences to be noted for static
         * binaries from the 2 operating systems:
         *
         *    1) Irix binaries have their .text section before their .init
         *       section. Linux binaries are just the opposite.
         *
         *    2) Irix binaries usually have <= 12 sections and Linux
         *       binaries have > 20.
         *
         * We will use Method #2 since Method #1 would require us to read in
         * the section headers which is way too much overhead. This appears
         * to work for everything we have ran into so far. If anyone has a
         * better method to tell the binaries apart, I'm listening.
         */
        if (elf_ex.e_shnum > 20)
                goto out;

        print_elfhdr(&elf_ex);

        /* Now read in all of the header information */
        size = elf_ex.e_phentsize * elf_ex.e_phnum;
        if (size > 65536)
                goto out;
        elf_phdata = kmalloc(size, GFP_KERNEL);
        if (elf_phdata == NULL) {
                retval = -ENOMEM;
                goto out;
        }

        retval = kernel_read(bprm->file, elf_ex.e_phoff, (char *)elf_phdata, size);
        if (retval < 0)
                goto out_free_ph;

        dump_phdrs(elf_phdata, elf_ex.e_phnum);

        /* Set some things for later. */
        for (i = 0; i < elf_ex.e_phnum; i++) {
                switch (elf_phdata[i].p_type) {
                case PT_INTERP:
                        has_interp = 1;
                        elf_ihdr = &elf_phdata[i];
                        break;
                case PT_PHDR:
                        has_ephdr = 1;
                        elf_ephdr = &elf_phdata[i];
                        break;
                };
        }

        pr_debug("\n");

        elf_bss = 0;
        elf_brk = 0;

        elf_stack = 0xffffffff;
        elf_interpreter = NULL;
        start_code = 0xffffffff;
        end_code = 0;
        end_data = 0;

        /*
         * If we get a return value, we change the value to be ENOEXEC
         * so that we can exit gracefully and the main binary format
         * search loop in 'fs/exec.c' will move onto the next handler
         * which should be the normal ELF binary handler.
         */
        retval = look_for_irix_interpreter(&elf_interpreter, &interpreter,
                                           &interp_elf_ex, elf_phdata, bprm,
                                           elf_ex.e_phnum);
        if (retval) {
                retval = -ENOEXEC;
                goto out_free_file;
        }

        if (elf_interpreter) {
                retval = verify_irix_interpreter(&interp_elf_ex);
                if (retval)
                        goto out_free_interp;
        }

        /* OK, we are done with that, now set up the arg stuff,
         * and then start this sucker up.
         */
        retval = -E2BIG;
        if (!bprm->sh_bang && !bprm->p)
                goto out_free_interp;

        /* Flush all traces of the currently running executable */
        retval = flush_old_exec(bprm);
        if (retval)
                goto out_free_dentry;

        /* OK, This is the point of no return */
        current->mm->end_data = 0;
        current->mm->end_code = 0;
        current->mm->mmap = NULL;
        current->flags &= ~PF_FORKNOEXEC;
        elf_entry = (unsigned int) elf_ex.e_entry;

        /* Do this so that we can load the interpreter, if need be.  We will
         * change some of these later.
         */
        setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
        current->mm->start_stack = bprm->p;

        /* At this point, we assume that the image should be loaded at
         * fixed address, not at a variable address.
         */
        old_fs = get_fs();
        set_fs(get_ds());

        map_executable(bprm->file, elf_phdata, elf_ex.e_phnum, &elf_stack,
                       &load_addr, &start_code, &elf_bss, &end_code,
                       &end_data, &elf_brk);

        if (elf_interpreter) {
                retval = map_interpreter(elf_phdata, &interp_elf_ex,
                                         interpreter, &interp_load_addr,
                                         elf_ex.e_phnum, old_fs, &elf_entry);
                kfree(elf_interpreter);
                if (retval) {
                        set_fs(old_fs);
                        printk("Unable to load IRIX ELF interpreter\n");
                        send_sig(SIGSEGV, current, 0);
                        retval = 0;
                        goto out_free_file;
                }
        }

        set_fs(old_fs);

        kfree(elf_phdata);
        set_personality(PER_IRIX32);
        set_binfmt(&irix_format);
        compute_creds(bprm);
        current->flags &= ~PF_FORKNOEXEC;
        bprm->p = (unsigned long)
          create_irix_tables((char *)bprm->p, bprm->argc, bprm->envc,
                        (elf_interpreter ? &elf_ex : NULL),
                        load_addr, interp_load_addr, regs, elf_ephdr);
        current->mm->start_brk = current->mm->brk = elf_brk;
        current->mm->end_code = end_code;
        current->mm->start_code = start_code;
        current->mm->end_data = end_data;
        current->mm->start_stack = bprm->p;

        /* Calling set_brk effectively mmaps the pages that we need for the
         * bss and break sections.
         */
        set_brk(elf_bss, elf_brk);

        /*
         * IRIX maps a page at 0x200000 which holds some system
         * information.  Programs depend on this.
         */
        irix_map_prda_page();

        padzero(elf_bss);

        pr_debug("(start_brk) %lx\n" , (long) current->mm->start_brk);
        pr_debug("(end_code) %lx\n" , (long) current->mm->end_code);
        pr_debug("(start_code) %lx\n" , (long) current->mm->start_code);
        pr_debug("(end_data) %lx\n" , (long) current->mm->end_data);
        pr_debug("(start_stack) %lx\n" , (long) current->mm->start_stack);
        pr_debug("(brk) %lx\n" , (long) current->mm->brk);

#if 0 /* XXX No fucking way dude... */
        /* 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.
         */
        down_write(&current->mm->mmap_sem);
        (void) do_mmap(NULL, 0, 4096, PROT_READ | PROT_EXEC,
                       MAP_FIXED | MAP_PRIVATE, 0);
        up_write(&current->mm->mmap_sem);
#endif

        start_thread(regs, elf_entry, bprm->p);
        if (current->ptrace & PT_PTRACED)
                send_sig(SIGTRAP, current, 0);
        return 0;
out:
        return retval;

out_free_dentry:
        allow_write_access(interpreter);
        fput(interpreter);
out_free_interp:
        kfree(elf_interpreter);
out_free_file:
out_free_ph:
        kfree(elf_phdata);
        goto out;
}

/* This is really simpleminded and specialized - we are loading an
 * a.out library that is given an ELF header.
 */
static int load_irix_library(struct file *file)
{
        struct elfhdr elf_ex;
        struct elf_phdr *elf_phdata  =  NULL;
        unsigned int len = 0;
        int elf_bss = 0;
        int retval;
        unsigned int bss;
        int error;
        int i, j, k;

        error = kernel_read(file, 0, (char *) &elf_ex, sizeof(elf_ex));
        if (error != sizeof(elf_ex))
                return -ENOEXEC;

        if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
                return -ENOEXEC;

        /* First of all, some simple consistency checks. */
        if (elf_ex.e_type != ET_EXEC || elf_ex.e_phnum > 2 ||
           !file->f_op->mmap)
                return -ENOEXEC;

        /* Now read in all of the header information. */
        if (sizeof(struct elf_phdr) * elf_ex.e_phnum > PAGE_SIZE)
                return -ENOEXEC;

        elf_phdata = kmalloc(sizeof(struct elf_phdr) * elf_ex.e_phnum, GFP_KERNEL);
        if (elf_phdata == NULL)
                return -ENOMEM;

        retval = kernel_read(file, elf_ex.e_phoff, (char *) elf_phdata,
                           sizeof(struct elf_phdr) * elf_ex.e_phnum);

        j = 0;
        for (i=0; i<elf_ex.e_phnum; i++)
                if ((elf_phdata + i)->p_type == PT_LOAD) j++;

        if (j != 1)  {
                kfree(elf_phdata);
                return -ENOEXEC;
        }

        while (elf_phdata->p_type != PT_LOAD) elf_phdata++;

        /* Now use mmap to map the library into memory. */
        down_write(&current->mm->mmap_sem);
        error = do_mmap(file,
                        elf_phdata->p_vaddr & 0xfffff000,
                        elf_phdata->p_filesz + (elf_phdata->p_vaddr & 0xfff),
                        PROT_READ | PROT_WRITE | PROT_EXEC,
                        MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
                        elf_phdata->p_offset & 0xfffff000);
        up_write(&current->mm->mmap_sem);

        k = elf_phdata->p_vaddr + elf_phdata->p_filesz;
        if (k > elf_bss) elf_bss = k;

        if (error != (elf_phdata->p_vaddr & 0xfffff000)) {
                kfree(elf_phdata);
                return error;
        }

        padzero(elf_bss);

        len = (elf_phdata->p_filesz + elf_phdata->p_vaddr+ 0xfff) & 0xfffff000;
        bss = elf_phdata->p_memsz + elf_phdata->p_vaddr;
        if (bss > len) {
          down_write(&current->mm->mmap_sem);
          do_brk(len, bss-len);
          up_write(&current->mm->mmap_sem);
        }
        kfree(elf_phdata);
        return 0;
}

/* Called through irix_syssgi() to map an elf image given an FD,
 * a phdr ptr USER_PHDRP in userspace, and a count CNT telling how many
 * phdrs there are in the USER_PHDRP array.  We return the vaddr the
 * first phdr was successfully mapped to.
 */
unsigned long irix_mapelf(int fd, struct elf_phdr __user *user_phdrp, int cnt)
{
        unsigned long type, vaddr, filesz, offset, flags;
        struct elf_phdr __user *hp;
        struct file *filp;
        int i, retval;

        pr_debug("irix_mapelf: fd[%d] user_phdrp[%p] cnt[%d]\n",
                 fd, user_phdrp, cnt);

        /* First get the verification out of the way. */
        hp = user_phdrp;
        if (!access_ok(VERIFY_READ, hp, (sizeof(struct elf_phdr) * cnt))) {
                pr_debug("irix_mapelf: bad pointer to ELF PHDR!\n");

                return -EFAULT;
        }

        dump_phdrs(user_phdrp, cnt);

        for (i = 0; i < cnt; i++, hp++) {
                if (__get_user(type, &hp->p_type))
                        return -EFAULT;
                if (type != PT_LOAD) {
                        printk("irix_mapelf: One section is not PT_LOAD!\n");
                        return -ENOEXEC;
                }
        }

        filp = fget(fd);
        if (!filp)
                return -EACCES;
        if (!filp->f_op) {
                printk("irix_mapelf: Bogon filp!\n");
                fput(filp);
                return -EACCES;
        }

        hp = user_phdrp;
        for (i = 0; i < cnt; i++, hp++) {
                int prot;

                retval = __get_user(vaddr, &hp->p_vaddr);
                retval |= __get_user(filesz, &hp->p_filesz);
                retval |= __get_user(offset, &hp->p_offset);
                retval |= __get_user(flags, &hp->p_flags);
                if (retval)
                        return retval;

                prot  = (flags & PF_R) ? PROT_READ : 0;
                prot |= (flags & PF_W) ? PROT_WRITE : 0;
                prot |= (flags & PF_X) ? PROT_EXEC : 0;

                down_write(&current->mm->mmap_sem);
                retval = do_mmap(filp, (vaddr & 0xfffff000),
                                 (filesz + (vaddr & 0xfff)),
                                 prot, (MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE),
                                 (offset & 0xfffff000));
                up_write(&current->mm->mmap_sem);

                if (retval != (vaddr & 0xfffff000)) {
                        printk("irix_mapelf: do_mmap fails with %d!\n", retval);
                        fput(filp);
                        return retval;
                }
        }

        pr_debug("irix_mapelf: Success, returning %08lx\n",
                 (unsigned long) user_phdrp->p_vaddr);

        fput(filp);

        if (__get_user(vaddr, &user_phdrp->p_vaddr))
                return -EFAULT;

        return vaddr;
}

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

/* These are the only things you should do on a core-file: use only these
 * functions to write out all the necessary info.
 */
static int dump_write(struct file *file, const void __user *addr, int nr)
{
        return file->f_op->write(file, (const char __user *) addr, nr, &file->f_pos) == nr;
}

static int dump_seek(struct file *file, off_t off)
{
        if (file->f_op->llseek) {
                if (file->f_op->llseek(file, off, 0) != off)
                        return 0;
        } else
                file->f_pos = off;
        return 1;
}

/* Decide whether a segment is worth dumping; default is yes to be
 * sure (missing info is worse than too much; etc).
 * Personally I'd include everything, and use the coredump limit...
 *
 * I think we should skip something. But I am not sure how. H.J.
 */
static inline int maydump(struct vm_area_struct *vma)
{
        if (!(vma->vm_flags & (VM_READ|VM_WRITE|VM_EXEC)))
                return 0;
#if 1
        if (vma->vm_flags & (VM_WRITE|VM_GROWSUP|VM_GROWSDOWN))
                return 1;
        if (vma->vm_flags & (VM_READ|VM_EXEC|VM_EXECUTABLE|VM_SHARED))
                return 0;
#endif
        return 1;
}

/* 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 DUMP_WRITE(addr, nr)    \
        if (!dump_write(file, (addr), (nr))) \
                goto end_coredump;
#define DUMP_SEEK(off)  \
        if (!dump_seek(file, (off))) \
                goto end_coredump;

static int writenote(struct memelfnote *men, struct file *file)
{
        struct elf_note en;

        en.n_namesz = strlen(men->name) + 1;
        en.n_descsz = men->datasz;
        en.n_type = men->type;

        DUMP_WRITE(&en, sizeof(en));
        DUMP_WRITE(men->name, en.n_namesz);
        /* XXX - cast from long long to long to avoid need for libgcc.a */
        DUMP_SEEK(roundup((unsigned long)file->f_pos, 4));      /* XXX */
        DUMP_WRITE(men->data, men->datasz);
        DUMP_SEEK(roundup((unsigned long)file->f_pos, 4));      /* XXX */

        return 1;

end_coredump:
        return 0;
}
#undef DUMP_WRITE
#undef DUMP_SEEK

#define DUMP_WRITE(addr, nr)    \
        if (!dump_write(file, (addr), (nr))) \
                goto end_coredump;
#define DUMP_SEEK(off)  \
        if (!dump_seek(file, (off))) \
                goto end_coredump;

/* 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 irix_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit)
{
        int has_dumped = 0;
        mm_segment_t fs;
        int segs;
        int i;
        size_t size;
        struct vm_area_struct *vma;
        struct elfhdr elf;
        off_t offset = 0, dataoff;
        int numnote = 3;
        struct memelfnote notes[3];
        struct elf_prstatus prstatus;   /* NT_PRSTATUS */
        elf_fpregset_t fpu;             /* NT_PRFPREG */
        struct elf_prpsinfo psinfo;     /* NT_PRPSINFO */

        /* Count what's needed to dump, up to the limit of coredump size. */
        segs = 0;
        size = 0;
        for (vma = current->mm->mmap; vma != NULL; vma = vma->vm_next) {
                if (maydump(vma))
                {
                        int sz = vma->vm_end-vma->vm_start;

                        if (size+sz >= limit)
                                break;
                        else
                                size += sz;
                }

                segs++;
        }
        pr_debug("irix_core_dump: %d segs taking %d bytes\n", segs, size);

        /* Set up header. */
        memcpy(elf.e_ident, ELFMAG, SELFMAG);
        elf.e_ident[EI_CLASS] = ELFCLASS32;
        elf.e_ident[EI_DATA] = ELFDATA2LSB;
        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(elf);
        elf.e_shoff = 0;
        elf.e_flags = 0;
        elf.e_ehsize = sizeof(elf);
        elf.e_phentsize = sizeof(struct elf_phdr);
        elf.e_phnum = segs+1;           /* Include notes. */
        elf.e_shentsize = 0;
        elf.e_shnum = 0;
        elf.e_shstrndx = 0;

        fs = get_fs();
        set_fs(KERNEL_DS);

        has_dumped = 1;
        current->flags |= PF_DUMPCORE;

        DUMP_WRITE(&elf, sizeof(elf));
        offset += sizeof(elf);                          /* Elf header. */
        offset += (segs+1) * sizeof(struct elf_phdr);   /* Program headers. */

        /* Set up the notes in similar form to SVR4 core dumps made
         * with info from their /proc.
         */
        memset(&psinfo, 0, sizeof(psinfo));
        memset(&prstatus, 0, sizeof(prstatus));

        notes[0].name = "CORE";
        notes[0].type = NT_PRSTATUS;
        notes[0].datasz = sizeof(prstatus);
        notes[0].data = &prstatus;
        prstatus.pr_info.si_signo = prstatus.pr_cursig = signr;
        prstatus.pr_sigpend = current->pending.signal.sig[0];
        prstatus.pr_sighold = current->blocked.sig[0];
        psinfo.pr_pid = prstatus.pr_pid = task_pid_vnr(current);
        psinfo.pr_ppid = prstatus.pr_ppid = task_pid_vnr(current->parent);
        psinfo.pr_pgrp = prstatus.pr_pgrp = task_pgrp_vnr(current);
        psinfo.pr_sid = prstatus.pr_sid = task_session_vnr(current);
        if (thread_group_leader(current)) {
                /*
                 * This is the record for the group leader.  Add in the
                 * cumulative times of previous dead threads.  This total
                 * won't include the time of each live thread whose state
                 * is included in the core dump.  The final total reported
                 * to our parent process when it calls wait4 will include
                 * those sums as well as the little bit more time it takes
                 * this and each other thread to finish dying after the
                 * core dump synchronization phase.
                 */
                jiffies_to_timeval(current->utime + current->signal->utime,
                                   &prstatus.pr_utime);
                jiffies_to_timeval(current->stime + current->signal->stime,
                                   &prstatus.pr_stime);
        } else {
                jiffies_to_timeval(current->utime, &prstatus.pr_utime);
                jiffies_to_timeval(current->stime, &prstatus.pr_stime);
        }
        jiffies_to_timeval(current->signal->cutime, &prstatus.pr_cutime);
        jiffies_to_timeval(current->signal->cstime, &prstatus.pr_cstime);

        if (sizeof(elf_gregset_t) != sizeof(struct pt_regs)) {
                printk("sizeof(elf_gregset_t) (%d) != sizeof(struct pt_regs) "
                       "(%d)\n", sizeof(elf_gregset_t), sizeof(struct pt_regs));
        } else {
                *(struct pt_regs *)&prstatus.pr_reg = *regs;
        }

        notes[1].name = "CORE";
        notes[1].type = NT_PRPSINFO;
        notes[1].datasz = sizeof(psinfo);
        notes[1].data = &psinfo;
        i = current->state ? ffz(~current->state) + 1 : 0;
        psinfo.pr_state = i;
        psinfo.pr_sname = (i < 0 || i > 5) ? '.' : "RSDZTD"[i];
        psinfo.pr_zomb = psinfo.pr_sname == 'Z';
        psinfo.pr_nice = task_nice(current);
        psinfo.pr_flag = current->flags;
        psinfo.pr_uid = current->uid;
        psinfo.pr_gid = current->gid;
        {
                int i, len;

                set_fs(fs);

                len = current->mm->arg_end - current->mm->arg_start;
                len = len >= ELF_PRARGSZ ? ELF_PRARGSZ : len;
                (void *) copy_from_user(&psinfo.pr_psargs,
                               (const char __user *)current->mm->arg_start, len);
                for (i = 0; i < len; i++)
                        if (psinfo.pr_psargs[i] == 0)
                                psinfo.pr_psargs[i] = ' ';
                psinfo.pr_psargs[len] = 0;

                set_fs(KERNEL_DS);
        }
        strlcpy(psinfo.pr_fname, current->comm, sizeof(psinfo.pr_fname));

        /* Try to dump the FPU. */
        prstatus.pr_fpvalid = dump_fpu(regs, &fpu);
        if (!prstatus.pr_fpvalid) {
                numnote--;
        } else {
                notes[2].name = "CORE";
                notes[2].type = NT_PRFPREG;
                notes[2].datasz = sizeof(fpu);
                notes[2].data = &fpu;
        }

        /* Write notes phdr entry. */
        {
                struct elf_phdr phdr;
                int sz = 0;

                for (i = 0; i < numnote; i++)
                        sz += notesize(&notes[i]);

                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;

                offset += phdr.p_filesz;
                DUMP_WRITE(&phdr, sizeof(phdr));
        }

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

        /* Write program headers for segments dump. */
        for (vma = current->mm->mmap, i = 0;
                i < segs && vma != NULL; vma = vma->vm_next) {
                struct elf_phdr phdr;
                size_t sz;

                i++;

                sz = vma->vm_end - vma->vm_start;

                phdr.p_type = PT_LOAD;
                phdr.p_offset = offset;
                phdr.p_vaddr = vma->vm_start;
                phdr.p_paddr = 0;
                phdr.p_filesz = maydump(vma) ? sz : 0;
                phdr.p_memsz = sz;
                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 = PAGE_SIZE;

                DUMP_WRITE(&phdr, sizeof(phdr));
        }

        for (i = 0; i < numnote; i++)
                if (!writenote(&notes[i], file))
                        goto end_coredump;

        set_fs(fs);

        DUMP_SEEK(dataoff);

        for (i = 0, vma = current->mm->mmap;
            i < segs && vma != NULL;
            vma = vma->vm_next) {
                unsigned long addr = vma->vm_start;
                unsigned long len = vma->vm_end - vma->vm_start;

                if (!maydump(vma))
                        continue;
                i++;
                pr_debug("elf_core_dump: writing %08lx %lx\n", addr, len);
                DUMP_WRITE((void __user *)addr, len);
        }

        if ((off_t) file->f_pos != offset) {
                /* Sanity check. */
                printk("elf_core_dump: file->f_pos (%ld) != offset (%ld)\n",
                       (off_t) file->f_pos, offset);
        }

end_coredump:
        set_fs(fs);
        return has_dumped;
}

static int __init init_irix_binfmt(void)
{
        extern int init_inventory(void);
        extern asmlinkage unsigned long sys_call_table;
        extern asmlinkage unsigned long sys_call_table_irix5;

        init_inventory();

        /*
         * Copy the IRIX5 syscall table (8000 bytes) into the main syscall
         * table. The IRIX5 calls are located by an offset of 8000 bytes
         * from the beginning of the main table.
         */
        memcpy((void *) ((unsigned long) &sys_call_table + 8000),
                &sys_call_table_irix5, 8000);

        return register_binfmt(&irix_format);
}

static void __exit exit_irix_binfmt(void)
{
        /*
         * Remove the Irix ELF loader.
         */
        unregister_binfmt(&irix_format);
}

module_init(init_irix_binfmt)
module_exit(exit_irix_binfmt)