source: mainline/kernel/arch/amd64/src/cpu/cpu.c@ 49e6c6b4

/*
 * Copyright (c) 2001-2004 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup amd64
 * @{
 */
/** @file
 */

#include <cpu.h>
#include <arch/cpu.h>
#include <arch/cpuid.h>
#include <arch/pm.h>

#include <arch.h>
#include <typedefs.h>
#include <print.h>
#include <fpu_context.h>

/*
 * Identification of CPUs.
 * Contains only non-MP-Specification specific SMP code.
 */
#define AMD_CPUID_EBX  UINT32_C(0x68747541)
#define AMD_CPUID_ECX  UINT32_C(0x444d4163)
#define AMD_CPUID_EDX  UINT32_C(0x69746e65)

#define INTEL_CPUID_EBX  UINT32_C(0x756e6547)
#define INTEL_CPUID_ECX  UINT32_C(0x6c65746e)
#define INTEL_CPUID_EDX  UINT32_C(0x49656e69)

enum vendor {
        VendorUnknown = 0,
        VendorAMD,
        VendorIntel
};

static const char *vendor_str[] = {
        "Unknown Vendor",
        "AuthenticAMD",
        "GenuineIntel"
};


/** Setup flags on processor so that we can use the FPU
 *
 * cr0.osfxsr = 1 -> we do support fxstor/fxrestor
 * cr0.em = 0 -> we do not emulate coprocessor
 * cr0.mp = 1 -> we do want lazy context switch
 */
void cpu_setup_fpu(void)
{
        asm volatile (
                "movq %%cr0, %%rax\n"
                "btsq $1, %%rax\n"  /* cr0.mp */
                "btrq $2, %%rax\n"  /* cr0.em */
                "movq %%rax, %%cr0\n"
                
                "movq %%cr4, %%rax\n"
                "bts $9, %%rax\n"   /* cr4.osfxsr */
                "movq %%rax, %%cr4\n"
                ::: "%rax"
        );
}

/** Set the TS flag to 1.
 *
 * If a thread accesses coprocessor, exception is run, which 
 * does a lazy fpu context switch.
 *
 */
void fpu_disable(void)
{
        asm volatile (
                "mov %%cr0, %%rax\n"
                "bts $3, %%rax\n"
                "mov %%rax, %%cr0\n"
                ::: "%rax"
        );
}

void fpu_enable(void)
{
        asm volatile (
                "mov %%cr0, %%rax\n"
                "btr $3, %%rax\n"
                "mov %%rax, %%cr0\n"
                ::: "%rax"
        );
}

void cpu_arch_init(void)
{
        CPU->arch.tss = tss_p;
        CPU->arch.tss->iomap_base = &CPU->arch.tss->iomap[0] -
            ((uint8_t *) CPU->arch.tss);
        CPU->fpu_owner = NULL;
}

void cpu_identify(void)
{
        cpu_info_t info;
        
        CPU->arch.vendor = VendorUnknown;
        if (has_cpuid()) {
                cpuid(INTEL_CPUID_LEVEL, &info);
                
                /*
                 * Check for AMD processor.
                 */
                if ((info.cpuid_ebx == AMD_CPUID_EBX) &&
                    (info.cpuid_ecx == AMD_CPUID_ECX) &&
                    (info.cpuid_edx == AMD_CPUID_EDX)) {
                        CPU->arch.vendor = VendorAMD;
                }
                
                /*
                 * Check for Intel processor.
                 */
                if ((info.cpuid_ebx == INTEL_CPUID_EBX) &&
                    (info.cpuid_ecx == INTEL_CPUID_ECX) &&
                    (info.cpuid_edx == INTEL_CPUID_EDX)) {
                        CPU->arch.vendor = VendorIntel;
                }
                
                cpuid(INTEL_CPUID_STANDARD, &info);
                CPU->arch.family = (info.cpuid_eax >> 8) & 0xf;
                CPU->arch.model = (info.cpuid_eax >> 4) & 0xf;
                CPU->arch.stepping = (info.cpuid_eax >> 0) & 0xf;
        }
}

void cpu_print_report(cpu_t* m)
{
        printf("cpu%d: (%s family=%d model=%d stepping=%d apicid=%u) %dMHz\n",
            m->id, vendor_str[m->arch.vendor], m->arch.family, m->arch.model,
            m->arch.stepping, m->arch.id, m->frequency_mhz);
}

/** @}
 */