Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 *  Copyright (C) 1994  Linus Torvalds

 *

 *  Cyrix stuff, June 1998 by:

 *      - Rafael R. Reilova (moved everything from head.S),

 *        <rreilova@ececs.uc.edu>

 *      - Channing Corn (tests & fixes),

 *      - Andrew D. Balsa (code cleanup).

 */

#include <linux/init.h>

#include <linux/utsname.h>

#include <asm/bugs.h>

#include <asm/processor.h>

#include <asm/i387.h>

#include <asm/msr.h>

#include <asm/paravirt.h>

#include <asm/alternative.h>

static int __init no_halt(char *s)

{

        boot_cpu_data.hlt_works_ok = 0;

        return 1;

}

__setup("no-hlt", no_halt);

static int __init mca_pentium(char *s)

{

        mca_pentium_flag = 1;

        return 1;

}

__setup("mca-pentium", mca_pentium);

static int __init no_387(char *s)

{

        boot_cpu_data.hard_math = 0;

        write_cr0(0xE | read_cr0());

        return 1;

}

__setup("no387", no_387);

static double __initdata x = 4195835.0;

static double __initdata y = 3145727.0;

/*

 * This used to check for exceptions..

 * However, it turns out that to support that,

 * the XMM trap handlers basically had to

 * be buggy. So let's have a correct XMM trap

 * handler, and forget about printing out

 * some status at boot.

 *

 * We should really only care about bugs here

 * anyway. Not features.

 */

static void __init check_fpu(void)

{

        if (!boot_cpu_data.hard_math) {

#ifndef CONFIG_MATH_EMULATION

                printk(KERN_EMERG "No coprocessor found and no math emulation present.\n");

                printk(KERN_EMERG "Giving up.\n");

                for (;;) ;

#endif

                return;

        }

/* trap_init() enabled FXSR and company _before_ testing for FP problems here. */

        /* Test for the divl bug.. */

        __asm__("fninit\n\t"

                "fldl %1\n\t"

                "fdivl %2\n\t"

                "fmull %2\n\t"

                "fldl %1\n\t"

                "fsubp %%st,%%st(1)\n\t"

                "fistpl %0\n\t"

                "fwait\n\t"

                "fninit"

                : "=m" (*&boot_cpu_data.fdiv_bug)

                : "m" (*&x), "m" (*&y));

        if (boot_cpu_data.fdiv_bug)

                printk("Hmm, FPU with FDIV bug.\n");

}

static void __init check_hlt(void)

{

        if (paravirt_enabled())

                return;

        printk(KERN_INFO "Checking 'hlt' instruction... ");

        if (!boot_cpu_data.hlt_works_ok) {

                printk("disabled\n");

                return;

        }

        halt();

        halt();

        halt();

        halt();

        printk("OK.\n");

}

/*

 *      Most 386 processors have a bug where a POPAD can lock the

 *      machine even from user space.

 */

static void __init check_popad(void)

{

#ifndef CONFIG_X86_POPAD_OK

        int res, inp = (int) &res;

        printk(KERN_INFO "Checking for popad bug... ");

        __asm__ __volatile__(

          "movl $12345678,%%eax; movl $0,%%edi; pusha; popa; movl (%%edx,%%edi),%%ecx "

          : "=&a" (res)

          : "d" (inp)

          : "ecx", "edi" );

        /* If this fails, it means that any user program may lock the CPU hard. Too bad. */

        if (res != 12345678) printk( "Buggy.\n" );

                        else printk( "OK.\n" );

#endif

}

/*

 * Check whether we are able to run this kernel safely on SMP.

 *

 * - In order to run on a i386, we need to be compiled for i386

 *   (for due to lack of "invlpg" and working WP on a i386)

 * - In order to run on anything without a TSC, we need to be

 *   compiled for a i486.

 * - In order to support the local APIC on a buggy Pentium machine,

 *   we need to be compiled with CONFIG_X86_GOOD_APIC disabled,

 *   which happens implicitly if compiled for a Pentium or lower

 *   (unless an advanced selection of CPU features is used) as an

 *   otherwise config implies a properly working local APIC without

 *   the need to do extra reads from the APIC.

*/

static void __init check_config(void)

{

/*

 * We'd better not be a i386 if we're configured to use some

 * i486+ only features! (WP works in supervisor mode and the

 * new "invlpg" and "bswap" instructions)

 */

#if defined(CONFIG_X86_WP_WORKS_OK) || defined(CONFIG_X86_INVLPG) || defined(CONFIG_X86_BSWAP)

        if (boot_cpu_data.x86 == 3)

                panic("Kernel requires i486+ for 'invlpg' and other features");

#endif

/*

 * If we configured ourselves for a TSC, we'd better have one!

 */

#ifdef CONFIG_X86_TSC

        if (!cpu_has_tsc && !tsc_disable)

                panic("Kernel compiled for Pentium+, requires TSC feature!");

#endif

/*

 * If we were told we had a good local APIC, check for buggy Pentia,

 * i.e. all B steppings and the C2 stepping of P54C when using their

 * integrated APIC (see 11AP erratum in "Pentium Processor

 * Specification Update").

 */

#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86_GOOD_APIC)

        if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL

            && cpu_has_apic

            && boot_cpu_data.x86 == 5

            && boot_cpu_data.x86_model == 2

            && (boot_cpu_data.x86_mask < 6 || boot_cpu_data.x86_mask == 11))

                panic("Kernel compiled for PMMX+, assumes a local APIC without the read-before-write bug!");

#endif

}

void __init check_bugs(void)

{

        identify_boot_cpu();

#ifndef CONFIG_SMP

        printk("CPU: ");

        print_cpu_info(&boot_cpu_data);

#endif

        check_config();

        check_fpu();

        check_hlt();

        check_popad();

        init_utsname()->machine[1] = '0' + (boot_cpu_data.x86 > 6 ? 6 : boot_cpu_data.x86);

        alternative_instructions();

}