common.c

linux 内核源代码

{
	if (cpu_has(c, X86_FEATURE_PN) && disable_x86_serial_nr ) {
		/* Disable processor serial number */
		unsigned long lo,hi;
		rdmsr(MSR_IA32_BBL_CR_CTL,lo,hi);
		lo |= 0x200000;
		wrmsr(MSR_IA32_BBL_CR_CTL,lo,hi);
		printk(KERN_NOTICE "CPU serial number disabled.\n");
		clear_bit(X86_FEATURE_PN, c->x86_capability);

		/* Disabling the serial number may affect the cpuid level */
		c->cpuid_level = cpuid_eax(0);
	}
}

static int __init x86_serial_nr_setup(char *s)
{
	disable_x86_serial_nr = 0;
	return 1;
}
__setup("serialnumber", x86_serial_nr_setup);



/*
 * This does the hard work of actually picking apart the CPU stuff...
 */
static void __cpuinit identify_cpu(struct cpuinfo_x86 *c)
{
	int i;

	c->loops_per_jiffy = loops_per_jiffy;
	c->x86_cache_size = -1;
	c->x86_vendor = X86_VENDOR_UNKNOWN;
	c->cpuid_level = -1;	/* CPUID not detected */
	c->x86_model = c->x86_mask = 0;	/* So far unknown... */
	c->x86_vendor_id[0] = '\0'; /* Unset */
	c->x86_model_id[0] = '\0';  /* Unset */
	c->x86_max_cores = 1;
	c->x86_clflush_size = 32;
	memset(&c->x86_capability, 0, sizeof c->x86_capability);

	if (!have_cpuid_p()) {
		/* First of all, decide if this is a 486 or higher */
		/* It's a 486 if we can modify the AC flag */
		if ( flag_is_changeable_p(X86_EFLAGS_AC) )
			c->x86 = 4;
		else
			c->x86 = 3;
	}

	generic_identify(c);

	printk(KERN_DEBUG "CPU: After generic identify, caps:");
	for (i = 0; i < NCAPINTS; i++)
		printk(" %08lx", c->x86_capability[i]);
	printk("\n");

	if (this_cpu->c_identify) {
		this_cpu->c_identify(c);

		printk(KERN_DEBUG "CPU: After vendor identify, caps:");
		for (i = 0; i < NCAPINTS; i++)
			printk(" %08lx", c->x86_capability[i]);
		printk("\n");
	}

	/*
	 * Vendor-specific initialization.  In this section we
	 * canonicalize the feature flags, meaning if there are
	 * features a certain CPU supports which CPUID doesn't
	 * tell us, CPUID claiming incorrect flags, or other bugs,
	 * we handle them here.
	 *
	 * At the end of this section, c->x86_capability better
	 * indicate the features this CPU genuinely supports!
	 */
	if (this_cpu->c_init)
		this_cpu->c_init(c);

	/* Disable the PN if appropriate */
	squash_the_stupid_serial_number(c);

	/*
	 * The vendor-specific functions might have changed features.  Now
	 * we do "generic changes."
	 */

	/* TSC disabled? */
	if ( tsc_disable )
		clear_bit(X86_FEATURE_TSC, c->x86_capability);

	/* FXSR disabled? */
	if (disable_x86_fxsr) {
		clear_bit(X86_FEATURE_FXSR, c->x86_capability);
		clear_bit(X86_FEATURE_XMM, c->x86_capability);
	}

	/* SEP disabled? */
	if (disable_x86_sep)
		clear_bit(X86_FEATURE_SEP, c->x86_capability);

	if (disable_pse)
		clear_bit(X86_FEATURE_PSE, c->x86_capability);

	/* If the model name is still unset, do table lookup. */
	if ( !c->x86_model_id[0] ) {
		char *p;
		p = table_lookup_model(c);
		if ( p )
			strcpy(c->x86_model_id, p);
		else
			/* Last resort... */
			sprintf(c->x86_model_id, "%02x/%02x",
				c->x86, c->x86_model);
	}

	/* Now the feature flags better reflect actual CPU features! */

	printk(KERN_DEBUG "CPU: After all inits, caps:");
	for (i = 0; i < NCAPINTS; i++)
		printk(" %08lx", c->x86_capability[i]);
	printk("\n");

	/*
	 * On SMP, boot_cpu_data holds the common feature set between
	 * all CPUs; so make sure that we indicate which features are
	 * common between the CPUs.  The first time this routine gets
	 * executed, c == &boot_cpu_data.
	 */
	if ( c != &boot_cpu_data ) {
		/* AND the already accumulated flags with these */
		for ( i = 0 ; i < NCAPINTS ; i++ )
			boot_cpu_data.x86_capability[i] &= c->x86_capability[i];
	}

	/* Init Machine Check Exception if available. */
	mcheck_init(c);
}

void __init identify_boot_cpu(void)
{
	identify_cpu(&boot_cpu_data);
	sysenter_setup();
	enable_sep_cpu();
	mtrr_bp_init();
}

void __cpuinit identify_secondary_cpu(struct cpuinfo_x86 *c)
{
	BUG_ON(c == &boot_cpu_data);
	identify_cpu(c);
	enable_sep_cpu();
	mtrr_ap_init();
}

#ifdef CONFIG_X86_HT
void __cpuinit detect_ht(struct cpuinfo_x86 *c)
{
	u32 	eax, ebx, ecx, edx;
	int 	index_msb, core_bits;

	cpuid(1, &eax, &ebx, &ecx, &edx);

	if (!cpu_has(c, X86_FEATURE_HT) || cpu_has(c, X86_FEATURE_CMP_LEGACY))
		return;

	smp_num_siblings = (ebx & 0xff0000) >> 16;

	if (smp_num_siblings == 1) {
		printk(KERN_INFO  "CPU: Hyper-Threading is disabled\n");
	} else if (smp_num_siblings > 1 ) {

		if (smp_num_siblings > NR_CPUS) {
			printk(KERN_WARNING "CPU: Unsupported number of the "
					"siblings %d", smp_num_siblings);
			smp_num_siblings = 1;
			return;
		}

		index_msb = get_count_order(smp_num_siblings);
		c->phys_proc_id = phys_pkg_id((ebx >> 24) & 0xFF, index_msb);

		printk(KERN_INFO  "CPU: Physical Processor ID: %d\n",
		       c->phys_proc_id);

		smp_num_siblings = smp_num_siblings / c->x86_max_cores;

		index_msb = get_count_order(smp_num_siblings) ;

		core_bits = get_count_order(c->x86_max_cores);

		c->cpu_core_id = phys_pkg_id((ebx >> 24) & 0xFF, index_msb) &
					       ((1 << core_bits) - 1);

		if (c->x86_max_cores > 1)
			printk(KERN_INFO  "CPU: Processor Core ID: %d\n",
			       c->cpu_core_id);
	}
}
#endif

void __cpuinit print_cpu_info(struct cpuinfo_x86 *c)
{
	char *vendor = NULL;

	if (c->x86_vendor < X86_VENDOR_NUM)
		vendor = this_cpu->c_vendor;
	else if (c->cpuid_level >= 0)
		vendor = c->x86_vendor_id;

	if (vendor && strncmp(c->x86_model_id, vendor, strlen(vendor)))
		printk("%s ", vendor);

	if (!c->x86_model_id[0])
		printk("%d86", c->x86);
	else
		printk("%s", c->x86_model_id);

	if (c->x86_mask || c->cpuid_level >= 0) 
		printk(" stepping %02x\n", c->x86_mask);
	else
		printk("\n");
}

cpumask_t cpu_initialized __cpuinitdata = CPU_MASK_NONE;

/* This is hacky. :)
 * We're emulating future behavior.
 * In the future, the cpu-specific init functions will be called implicitly
 * via the magic of initcalls.
 * They will insert themselves into the cpu_devs structure.
 * Then, when cpu_init() is called, we can just iterate over that array.
 */

extern int intel_cpu_init(void);
extern int cyrix_init_cpu(void);
extern int nsc_init_cpu(void);
extern int amd_init_cpu(void);
extern int centaur_init_cpu(void);
extern int transmeta_init_cpu(void);
extern int nexgen_init_cpu(void);
extern int umc_init_cpu(void);

void __init early_cpu_init(void)
{
	intel_cpu_init();
	cyrix_init_cpu();
	nsc_init_cpu();
	amd_init_cpu();
	centaur_init_cpu();
	transmeta_init_cpu();
	nexgen_init_cpu();
	umc_init_cpu();
	early_cpu_detect();

#ifdef CONFIG_DEBUG_PAGEALLOC
	/* pse is not compatible with on-the-fly unmapping,
	 * disable it even if the cpus claim to support it.
	 */
	clear_bit(X86_FEATURE_PSE, boot_cpu_data.x86_capability);
	disable_pse = 1;
#endif
}

/* Make sure %fs is initialized properly in idle threads */
struct pt_regs * __devinit idle_regs(struct pt_regs *regs)
{
	memset(regs, 0, sizeof(struct pt_regs));
	regs->xfs = __KERNEL_PERCPU;
	return regs;
}

/* Current gdt points %fs at the "master" per-cpu area: after this,
 * it's on the real one. */
void switch_to_new_gdt(void)
{
	struct Xgt_desc_struct gdt_descr;

	gdt_descr.address = (long)get_cpu_gdt_table(smp_processor_id());
	gdt_descr.size = GDT_SIZE - 1;
	load_gdt(&gdt_descr);
	asm("mov %0, %%fs" : : "r" (__KERNEL_PERCPU) : "memory");
}

/*
 * cpu_init() initializes state that is per-CPU. Some data is already
 * initialized (naturally) in the bootstrap process, such as the GDT
 * and IDT. We reload them nevertheless, this function acts as a
 * 'CPU state barrier', nothing should get across.
 */
void __cpuinit cpu_init(void)
{
	int cpu = smp_processor_id();
	struct task_struct *curr = current;
	struct tss_struct * t = &per_cpu(init_tss, cpu);
	struct thread_struct *thread = &curr->thread;

	if (cpu_test_and_set(cpu, cpu_initialized)) {
		printk(KERN_WARNING "CPU#%d already initialized!\n", cpu);
		for (;;) local_irq_enable();
	}

	printk(KERN_INFO "Initializing CPU#%d\n", cpu);

	if (cpu_has_vme || cpu_has_tsc || cpu_has_de)
		clear_in_cr4(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);
	if (tsc_disable && cpu_has_tsc) {
		printk(KERN_NOTICE "Disabling TSC...\n");
		/**** FIX-HPA: DOES THIS REALLY BELONG HERE? ****/
		clear_bit(X86_FEATURE_TSC, boot_cpu_data.x86_capability);
		set_in_cr4(X86_CR4_TSD);
	}

	load_idt(&idt_descr);
	switch_to_new_gdt();

	/*
	 * Set up and load the per-CPU TSS and LDT
	 */
	atomic_inc(&init_mm.mm_count);
	curr->active_mm = &init_mm;
	if (curr->mm)
		BUG();
	enter_lazy_tlb(&init_mm, curr);

	load_esp0(t, thread);
	set_tss_desc(cpu,t);
	load_TR_desc();
	load_LDT(&init_mm.context);

#ifdef CONFIG_DOUBLEFAULT
	/* Set up doublefault TSS pointer in the GDT */
	__set_tss_desc(cpu, GDT_ENTRY_DOUBLEFAULT_TSS, &doublefault_tss);
#endif

	/* Clear %gs. */
	asm volatile ("mov %0, %%gs" : : "r" (0));

	/* Clear all 6 debug registers: */
	set_debugreg(0, 0);
	set_debugreg(0, 1);
	set_debugreg(0, 2);
	set_debugreg(0, 3);
	set_debugreg(0, 6);
	set_debugreg(0, 7);

	/*
	 * Force FPU initialization:
	 */
	current_thread_info()->status = 0;
	clear_used_math();
	mxcsr_feature_mask_init();
}

#ifdef CONFIG_HOTPLUG_CPU
void __cpuinit cpu_uninit(void)
{
	int cpu = raw_smp_processor_id();
	cpu_clear(cpu, cpu_initialized);

	/* lazy TLB state */
	per_cpu(cpu_tlbstate, cpu).state = 0;
	per_cpu(cpu_tlbstate, cpu).active_mm = &init_mm;
}
#endif