i386: move kernel/cpu

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 733 insertions, 0 deletions

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
new file mode 100644
index 000000000000..d506201d397c
--- /dev/null
+++ b/arch/x86/kernel/cpu/common.c
@@ -0,0 +1,733 @@
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/delay.h>
+#include <linux/smp.h>
+#include <linux/module.h>
+#include <linux/percpu.h>
+#include <linux/bootmem.h>
+#include <asm/semaphore.h>
+#include <asm/processor.h>
+#include <asm/i387.h>
+#include <asm/msr.h>
+#include <asm/io.h>
+#include <asm/mmu_context.h>
+#include <asm/mtrr.h>
+#include <asm/mce.h>
+#ifdef CONFIG_X86_LOCAL_APIC
+#include <asm/mpspec.h>
+#include <asm/apic.h>
+#include <mach_apic.h>
+#endif
+
+#include "cpu.h"
+
+DEFINE_PER_CPU(struct gdt_page, gdt_page) = { .gdt = {
+        [GDT_ENTRY_KERNEL_CS] = { 0x0000ffff, 0x00cf9a00 },
+        [GDT_ENTRY_KERNEL_DS] = { 0x0000ffff, 0x00cf9200 },
+        [GDT_ENTRY_DEFAULT_USER_CS] = { 0x0000ffff, 0x00cffa00 },
+        [GDT_ENTRY_DEFAULT_USER_DS] = { 0x0000ffff, 0x00cff200 },
+        /*
+         * Segments used for calling PnP BIOS have byte granularity.
+         * They code segments and data segments have fixed 64k limits,
+         * the transfer segment sizes are set at run time.
+         */
+        [GDT_ENTRY_PNPBIOS_CS32] = { 0x0000ffff, 0x00409a00 },/* 32-bit code */
+        [GDT_ENTRY_PNPBIOS_CS16] = { 0x0000ffff, 0x00009a00 },/* 16-bit code */
+        [GDT_ENTRY_PNPBIOS_DS] = { 0x0000ffff, 0x00009200 }, /* 16-bit data */
+        [GDT_ENTRY_PNPBIOS_TS1] = { 0x00000000, 0x00009200 },/* 16-bit data */
+        [GDT_ENTRY_PNPBIOS_TS2] = { 0x00000000, 0x00009200 },/* 16-bit data */
+        /*
+         * The APM segments have byte granularity and their bases
+         * are set at run time.  All have 64k limits.
+         */
+        [GDT_ENTRY_APMBIOS_BASE] = { 0x0000ffff, 0x00409a00 },/* 32-bit code */
+        /* 16-bit code */
+        [GDT_ENTRY_APMBIOS_BASE+1] = { 0x0000ffff, 0x00009a00 },
+        [GDT_ENTRY_APMBIOS_BASE+2] = { 0x0000ffff, 0x00409200 }, /* data */
+
+        [GDT_ENTRY_ESPFIX_SS] = { 0x00000000, 0x00c09200 },
+        [GDT_ENTRY_PERCPU] = { 0x00000000, 0x00000000 },
+} };
+EXPORT_PER_CPU_SYMBOL_GPL(gdt_page);
+
+static int cachesize_override __cpuinitdata = -1;
+static int disable_x86_fxsr __cpuinitdata;
+static int disable_x86_serial_nr __cpuinitdata = 1;
+static int disable_x86_sep __cpuinitdata;
+
+struct cpu_dev * cpu_devs[X86_VENDOR_NUM] = {};
+
+extern int disable_pse;
+
+static void __cpuinit default_init(struct cpuinfo_x86 * c)
+{
+        /* Not much we can do here... */
+        /* Check if at least it has cpuid */
+        if (c->cpuid_level == -1) {
+                /* No cpuid. It must be an ancient CPU */
+                if (c->x86 == 4)
+                        strcpy(c->x86_model_id, "486");
+                else if (c->x86 == 3)
+                        strcpy(c->x86_model_id, "386");
+        }
+}
+
+static struct cpu_dev __cpuinitdata default_cpu = {
+        .c_init = default_init,
+        .c_vendor = "Unknown",
+};
+static struct cpu_dev * this_cpu __cpuinitdata = &default_cpu;
+
+static int __init cachesize_setup(char *str)
+{
+        get_option (&str, &cachesize_override);
+        return 1;
+}
+__setup("cachesize=", cachesize_setup);
+
+int __cpuinit get_model_name(struct cpuinfo_x86 *c)
+{
+        unsigned int *v;
+        char *p, *q;
+
+        if (cpuid_eax(0x80000000) < 0x80000004)
+                return 0;
+
+        v = (unsigned int *) c->x86_model_id;
+        cpuid(0x80000002, &v[0], &v[1], &v[2], &v[3]);
+        cpuid(0x80000003, &v[4], &v[5], &v[6], &v[7]);
+        cpuid(0x80000004, &v[8], &v[9], &v[10], &v[11]);
+        c->x86_model_id[48] = 0;
+
+        /* Intel chips right-justify this string for some dumb reason;
+           undo that brain damage */
+        p = q = &c->x86_model_id[0];
+        while ( *p == ' ' )
+             p++;
+        if ( p != q ) {
+             while ( *p )
+                  *q++ = *p++;
+             while ( q <= &c->x86_model_id[48] )
+                  *q++ = '\0';  /* Zero-pad the rest */
+        }
+
+        return 1;
+}
+
+
+void __cpuinit display_cacheinfo(struct cpuinfo_x86 *c)
+{
+        unsigned int n, dummy, ecx, edx, l2size;
+
+        n = cpuid_eax(0x80000000);
+
+        if (n >= 0x80000005) {
+                cpuid(0x80000005, &dummy, &dummy, &ecx, &edx);
+                printk(KERN_INFO "CPU: L1 I Cache: %dK (%d bytes/line), D cache %dK (%d bytes/line)\n",
+                        edx>>24, edx&0xFF, ecx>>24, ecx&0xFF);
+                c->x86_cache_size=(ecx>>24)+(edx>>24);  
+        }
+
+        if (n < 0x80000006)     /* Some chips just has a large L1. */
+                return;
+
+        ecx = cpuid_ecx(0x80000006);
+        l2size = ecx >> 16;
+        
+        /* do processor-specific cache resizing */
+        if (this_cpu->c_size_cache)
+                l2size = this_cpu->c_size_cache(c,l2size);
+
+        /* Allow user to override all this if necessary. */
+        if (cachesize_override != -1)
+                l2size = cachesize_override;
+
+        if ( l2size == 0 )
+                return;         /* Again, no L2 cache is possible */
+
+        c->x86_cache_size = l2size;
+
+        printk(KERN_INFO "CPU: L2 Cache: %dK (%d bytes/line)\n",
+               l2size, ecx & 0xFF);
+}
+
+/* Naming convention should be: <Name> [(<Codename>)] */
+/* This table only is used unless init_<vendor>() below doesn't set it; */
+/* in particular, if CPUID levels 0x80000002..4 are supported, this isn't used */
+
+/* Look up CPU names by table lookup. */
+static char __cpuinit *table_lookup_model(struct cpuinfo_x86 *c)
+{
+        struct cpu_model_info *info;
+
+        if ( c->x86_model >= 16 )
+                return NULL;    /* Range check */
+
+        if (!this_cpu)
+                return NULL;
+
+        info = this_cpu->c_models;
+
+        while (info && info->family) {
+                if (info->family == c->x86)
+                        return info->model_names[c->x86_model];
+                info++;
+        }
+        return NULL;            /* Not found */
+}
+
+
+static void __cpuinit get_cpu_vendor(struct cpuinfo_x86 *c, int early)
+{
+        char *v = c->x86_vendor_id;
+        int i;
+        static int printed;
+
+        for (i = 0; i < X86_VENDOR_NUM; i++) {
+                if (cpu_devs[i]) {
+                        if (!strcmp(v,cpu_devs[i]->c_ident[0]) ||
+                            (cpu_devs[i]->c_ident[1] && 
+                             !strcmp(v,cpu_devs[i]->c_ident[1]))) {
+                                c->x86_vendor = i;
+                                if (!early)
+                                        this_cpu = cpu_devs[i];
+                                return;
+                        }
+                }
+        }
+        if (!printed) {
+                printed++;
+                printk(KERN_ERR "CPU: Vendor unknown, using generic init.\n");
+                printk(KERN_ERR "CPU: Your system may be unstable.\n");
+        }
+        c->x86_vendor = X86_VENDOR_UNKNOWN;
+        this_cpu = &default_cpu;
+}
+
+
+static int __init x86_fxsr_setup(char * s)
+{
+        /* Tell all the other CPU's to not use it... */
+        disable_x86_fxsr = 1;
+
+        /*
+         * ... and clear the bits early in the boot_cpu_data
+         * so that the bootup process doesn't try to do this
+         * either.
+         */
+        clear_bit(X86_FEATURE_FXSR, boot_cpu_data.x86_capability);
+        clear_bit(X86_FEATURE_XMM, boot_cpu_data.x86_capability);
+        return 1;
+}
+__setup("nofxsr", x86_fxsr_setup);
+
+
+static int __init x86_sep_setup(char * s)
+{
+        disable_x86_sep = 1;
+        return 1;
+}
+__setup("nosep", x86_sep_setup);
+
+
+/* Standard macro to see if a specific flag is changeable */
+static inline int flag_is_changeable_p(u32 flag)
+{
+        u32 f1, f2;
+
+        asm("pushfl\n\t"
+            "pushfl\n\t"
+            "popl %0\n\t"
+            "movl %0,%1\n\t"
+            "xorl %2,%0\n\t"
+            "pushl %0\n\t"
+            "popfl\n\t"
+            "pushfl\n\t"
+            "popl %0\n\t"
+            "popfl\n\t"
+            : "=&r" (f1), "=&r" (f2)
+            : "ir" (flag));
+
+        return ((f1^f2) & flag) != 0;
+}
+
+
+/* Probe for the CPUID instruction */
+static int __cpuinit have_cpuid_p(void)
+{
+        return flag_is_changeable_p(X86_EFLAGS_ID);
+}
+
+void __init cpu_detect(struct cpuinfo_x86 *c)
+{
+        /* Get vendor name */
+        cpuid(0x00000000, &c->cpuid_level,
+              (int *)&c->x86_vendor_id[0],
+              (int *)&c->x86_vendor_id[8],
+              (int *)&c->x86_vendor_id[4]);
+
+        c->x86 = 4;
+        if (c->cpuid_level >= 0x00000001) {
+                u32 junk, tfms, cap0, misc;
+                cpuid(0x00000001, &tfms, &misc, &junk, &cap0);
+                c->x86 = (tfms >> 8) & 15;
+                c->x86_model = (tfms >> 4) & 15;
+                if (c->x86 == 0xf)
+                        c->x86 += (tfms >> 20) & 0xff;
+                if (c->x86 >= 0x6)
+                        c->x86_model += ((tfms >> 16) & 0xF) << 4;
+                c->x86_mask = tfms & 15;
+                if (cap0 & (1<<19))
+                        c->x86_cache_alignment = ((misc >> 8) & 0xff) * 8;
+        }
+}
+
+/* Do minimum CPU detection early.
+   Fields really needed: vendor, cpuid_level, family, model, mask, cache alignment.
+   The others are not touched to avoid unwanted side effects.
+
+   WARNING: this function is only called on the BP.  Don't add code here
+   that is supposed to run on all CPUs. */
+static void __init early_cpu_detect(void)
+{
+        struct cpuinfo_x86 *c = &boot_cpu_data;
+
+        c->x86_cache_alignment = 32;
+
+        if (!have_cpuid_p())
+                return;
+
+        cpu_detect(c);
+
+        get_cpu_vendor(c, 1);
+}
+
+static void __cpuinit generic_identify(struct cpuinfo_x86 * c)
+{
+        u32 tfms, xlvl;
+        int ebx;
+
+        if (have_cpuid_p()) {
+                /* Get vendor name */
+                cpuid(0x00000000, &c->cpuid_level,
+                      (int *)&c->x86_vendor_id[0],
+                      (int *)&c->x86_vendor_id[8],
+                      (int *)&c->x86_vendor_id[4]);
+                
+                get_cpu_vendor(c, 0);
+                /* Initialize the standard set of capabilities */
+                /* Note that the vendor-specific code below might override */
+        
+                /* Intel-defined flags: level 0x00000001 */
+                if ( c->cpuid_level >= 0x00000001 ) {
+                        u32 capability, excap;
+                        cpuid(0x00000001, &tfms, &ebx, &excap, &capability);
+                        c->x86_capability[0] = capability;
+                        c->x86_capability[4] = excap;
+                        c->x86 = (tfms >> 8) & 15;
+                        c->x86_model = (tfms >> 4) & 15;
+                        if (c->x86 == 0xf)
+                                c->x86 += (tfms >> 20) & 0xff;
+                        if (c->x86 >= 0x6)
+                                c->x86_model += ((tfms >> 16) & 0xF) << 4;
+                        c->x86_mask = tfms & 15;
+#ifdef CONFIG_X86_HT
+                        c->apicid = phys_pkg_id((ebx >> 24) & 0xFF, 0);
+#else
+                        c->apicid = (ebx >> 24) & 0xFF;
+#endif
+                        if (c->x86_capability[0] & (1<<19))
+                                c->x86_clflush_size = ((ebx >> 8) & 0xff) * 8;
+                } else {
+                        /* Have CPUID level 0 only - unheard of */
+                        c->x86 = 4;
+                }
+
+                /* AMD-defined flags: level 0x80000001 */
+                xlvl = cpuid_eax(0x80000000);
+                if ( (xlvl & 0xffff0000) == 0x80000000 ) {
+                        if ( xlvl >= 0x80000001 ) {
+                                c->x86_capability[1] = cpuid_edx(0x80000001);
+                                c->x86_capability[6] = cpuid_ecx(0x80000001);
+                        }
+                        if ( xlvl >= 0x80000004 )
+                                get_model_name(c); /* Default name */
+                }
+
+                init_scattered_cpuid_features(c);
+        }
+
+        early_intel_workaround(c);
+
+#ifdef CONFIG_X86_HT
+        c->phys_proc_id = (cpuid_ebx(1) >> 24) & 0xff;
+#endif
+}
+
+static void __cpuinit squash_the_stupid_serial_number(struct cpuinfo_x86 *c)
+{
+        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