bootloader.c

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/*
 * arch/ia64/hp/sim/boot/bootloader.c
 *
 * Loads an ELF kernel.
 *
 * Copyright (C) 1998-2003 Hewlett-Packard Co
 *  David Mosberger-Tang <[email protected]>
 *  Stephane Eranian <[email protected]>
 *
 * 01/07/99 S.Eranian modified to pass command line arguments to kernel
 */
struct task_struct; /* forward declaration for elf.h */

#include <linux/elf.h>
#include <linux/init.h>
#include <linux/kernel.h>

#include <asm/elf.h>
#include <asm/intrinsics.h>
#include <asm/pal.h>
#include <asm/pgtable.h>
#include <asm/sal.h>

#include "ssc.h"

struct disk_req {
    unsigned long addr;
    unsigned len;
};

struct disk_stat {
    int fd;
    unsigned count;
};

extern void jmp_to_kernel (unsigned long bp, unsigned long e_entry);
extern struct ia64_boot_param *sys_fw_init (const char *args, int arglen);
extern void debug_break (void);

static void
cons_write (const char *buf)
{
    unsigned long ch;

    while ((ch = *buf++) != '\0') {
        ssc(ch, 0, 0, 0, SSC_PUTCHAR);
        if (ch == '\n')
          ssc('\r', 0, 0, 0, SSC_PUTCHAR);
    }
}

#define MAX_ARGS 32

void
start_bootloader (void)
{
    static char mem[4096];
    static char buffer[1024];
    unsigned long off;
    int fd, i;
    struct disk_req req;
    struct disk_stat stat;
    struct elfhdr *elf;
    struct elf_phdr *elf_phdr;  /* program header */
    unsigned long e_entry, e_phoff, e_phnum;
    register struct ia64_boot_param *bp;
    char *kpath, *args;
    long arglen = 0;

    ssc(0, 0, 0, 0, SSC_CONSOLE_INIT);

    /*
     * S.Eranian: extract the commandline argument from the simulator
     *
     * The expected format is as follows:
         *
     *  kernelname args...
     *
     * Both are optional but you can't have the second one without the first.
     */
    arglen = ssc((long) buffer, 0, 0, 0, SSC_GET_ARGS);

    kpath = "vmlinux";
    args = buffer;
    if (arglen > 0) {
        kpath = buffer;
        while (*args != ' ' && *args != '\0')
            ++args, --arglen;
        if (*args == ' ')
            *args++ = '\0', --arglen;
    }

    if (arglen <= 0) {
        args = "";
        arglen = 1;
    }

    fd = ssc((long) kpath, 1, 0, 0, SSC_OPEN);

    if (fd < 0) {
        cons_write(kpath);
        cons_write(": file not found, reboot now\n");
        for(;;);
    }
    stat.fd = fd;
    off = 0;

    req.len = sizeof(mem);
    req.addr = (long) mem;
    ssc(fd, 1, (long) &req, off, SSC_READ);
    ssc((long) &stat, 0, 0, 0, SSC_WAIT_COMPLETION);

    elf = (struct elfhdr *) mem;
    if (elf->e_ident[0] == 0x7f && strncmp(elf->e_ident + 1, "ELF", 3) != 0) {
        cons_write("not an ELF file\n");
        return;
    }
    if (elf->e_type != ET_EXEC) {
        cons_write("not an ELF executable\n");
        return;
    }
    if (!elf_check_arch(elf)) {
        cons_write("kernel not for this processor\n");
        return;
    }

    e_entry = elf->e_entry;
    e_phnum = elf->e_phnum;
    e_phoff = elf->e_phoff;

    cons_write("loading ");
    cons_write(kpath);
    cons_write("...\n");

    for (i = 0; i < e_phnum; ++i) {
        req.len = sizeof(*elf_phdr);
        req.addr = (long) mem;
        ssc(fd, 1, (long) &req, e_phoff, SSC_READ);
        ssc((long) &stat, 0, 0, 0, SSC_WAIT_COMPLETION);
        if (stat.count != sizeof(*elf_phdr)) {
            cons_write("failed to read phdr\n");
            return;
        }
        e_phoff += sizeof(*elf_phdr);

        elf_phdr = (struct elf_phdr *) mem;

        if (elf_phdr->p_type != PT_LOAD)
            continue;

        req.len = elf_phdr->p_filesz;
        req.addr = __pa(elf_phdr->p_paddr);
        ssc(fd, 1, (long) &req, elf_phdr->p_offset, SSC_READ);
        ssc((long) &stat, 0, 0, 0, SSC_WAIT_COMPLETION);
        memset((char *)__pa(elf_phdr->p_paddr) + elf_phdr->p_filesz, 0,
               elf_phdr->p_memsz - elf_phdr->p_filesz);
    }
    ssc(fd, 0, 0, 0, SSC_CLOSE);

    cons_write("starting kernel...\n");

    /* fake an I/O base address: */
    ia64_setreg(_IA64_REG_AR_KR0, 0xffffc000000UL);

    bp = sys_fw_init(args, arglen);

    ssc(0, (long) kpath, 0, 0, SSC_LOAD_SYMBOLS);

    debug_break();
    jmp_to_kernel((unsigned long) bp, e_entry);

    cons_write("kernel returned!\n");
    ssc(-1, 0, 0, 0, SSC_EXIT);
}