 12c247a671
			
		
	
	
	12c247a671
	
	
	
		
			
			> Diffing dmesg between git7 and git8 doesn't sched any light since
 > git8 also removed the printouts of the x86 caps as they were being
 > initialised and updated. I'm currently adding those printouts back
 > in the hope of seeing where and when the caps get broken.
That turned out to be very illuminating:
 --- dmesg-2.6.24-git7	2008-02-24 18:01:25.295851000 +0100
 +++ dmesg-2.6.24-git8	2008-02-24 18:01:25.530358000 +0100
 ...
 CPU: After generic identify, caps: 00000003 00000000 00000000 00000000 00000000 00000000 00000000 00000000
 CPU: After all inits, caps: 00000003 00000000 00000000 00000000 00000000 00000000 00000000 00000000
+CPU: After applying cleared_cpu_caps, caps: 00000013 00000000 00000000 00000000 00000000 00000000 00000000 00000000
Notice how the TSC cap bit goes from Off to On.
(The first two lines are printout loops from -git7 forward-ported
to -git8, the third line is the same printout loop added just after
the xor-with-cleared_cpu_caps[] loop.)
Here's how the breakage occurs:
1. arch/x86/kernel/tsc_32.c:tsc_init() sees !cpu_has_tsc,
   so bails and calls setup_clear_cpu_cap(X86_FEATURE_TSC).
2. include/asm-x86/cpufeature.h:setup_clear_cpu_cap(bit) clears
   the bit in boot_cpu_data and sets it in cleared_cpu_caps
3. arch/x86/kernel/cpu/common.c:identify_cpu() XORs all caps
   in with cleared_cpu_caps
   HOWEVER, at this point c->x86_capability correctly has TSC
   Off, cleared_cpu_caps has TSC On, so the XOR incorrectly
   sets TSC to On in c->x86_capability, with disastrous results.
The real bug is that clearing bits with XOR only works if the
bits are known to be 1 prior to the XOR, and that's not true here.
A simple fix is to convert the XOR to AND-NOT instead. The following
patch does that, and allows my 486 to boot 2.6.25-rc kernels again.
[ mingo@elte.hu: fixed a similar bug in setup_64.c as well. ]
The breakage was introduced via commit 7d851c8d3d.
Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
		
	
			
		
			
				
	
	
		
			733 lines
		
	
	
	
		
			18 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			733 lines
		
	
	
	
		
			18 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
| #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.
 | |
| 	 */
 | |
| 	/* 32-bit code */
 | |
| 	[GDT_ENTRY_PNPBIOS_CS32] = { { { 0x0000ffff, 0x00409a00 } } },
 | |
| 	/* 16-bit code */
 | |
| 	[GDT_ENTRY_PNPBIOS_CS16] = { { { 0x0000ffff, 0x00009a00 } } },
 | |
| 	/* 16-bit data */
 | |
| 	[GDT_ENTRY_PNPBIOS_DS] = { { { 0x0000ffff, 0x00009200 } } },
 | |
| 	/* 16-bit data */
 | |
| 	[GDT_ENTRY_PNPBIOS_TS1] = { { { 0x00000000, 0x00009200 } } },
 | |
| 	/* 16-bit data */
 | |
| 	[GDT_ENTRY_PNPBIOS_TS2] = { { { 0x00000000, 0x00009200 } } },
 | |
| 	/*
 | |
| 	 * The APM segments have byte granularity and their bases
 | |
| 	 * are set at run time.  All have 64k limits.
 | |
| 	 */
 | |
| 	/* 32-bit code */
 | |
| 	[GDT_ENTRY_APMBIOS_BASE] = { { { 0x0000ffff, 0x00409a00 } } },
 | |
| 	/* 16-bit code */
 | |
| 	[GDT_ENTRY_APMBIOS_BASE+1] = { { { 0x0000ffff, 0x00009a00 } } },
 | |
| 	/* data */
 | |
| 	[GDT_ENTRY_APMBIOS_BASE+2] = { { { 0x0000ffff, 0x00409200 } } },
 | |
| 
 | |
| 	[GDT_ENTRY_ESPFIX_SS] = { { { 0x00000000, 0x00c09200 } } },
 | |
| 	[GDT_ENTRY_PERCPU] = { { { 0x00000000, 0x00000000 } } },
 | |
| } };
 | |
| EXPORT_PER_CPU_SYMBOL_GPL(gdt_page);
 | |
| 
 | |
| __u32 cleared_cpu_caps[NCAPINTS] __cpuinitdata;
 | |
| 
 | |
| static int cachesize_override __cpuinitdata = -1;
 | |
| static int disable_x86_serial_nr __cpuinitdata = 1;
 | |
| 
 | |
| struct cpu_dev * cpu_devs[X86_VENDOR_NUM] = {};
 | |
| 
 | |
| 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)
 | |
| {
 | |
| 	setup_clear_cpu_cap(X86_FEATURE_FXSR);
 | |
| 	setup_clear_cpu_cap(X86_FEATURE_XMM);
 | |
| 	return 1;
 | |
| }
 | |
| __setup("nofxsr", x86_fxsr_setup);
 | |
| 
 | |
| 
 | |
| static int __init x86_sep_setup(char * s)
 | |
| {
 | |
| 	setup_clear_cpu_cap(X86_FEATURE_SEP);
 | |
| 	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, (unsigned int *)&c->cpuid_level,
 | |
| 	      (unsigned int *)&c->x86_vendor_id[0],
 | |
| 	      (unsigned int *)&c->x86_vendor_id[8],
 | |
| 	      (unsigned 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;
 | |
| 			c->x86_clflush_size = ((misc >> 8) & 0xff) * 8;
 | |
| 		}
 | |
| 	}
 | |
| }
 | |
| static void __cpuinit early_get_cap(struct cpuinfo_x86 *c)
 | |
| {
 | |
| 	u32 tfms, xlvl;
 | |
| 	unsigned int ebx;
 | |
| 
 | |
| 	memset(&c->x86_capability, 0, sizeof c->x86_capability);
 | |
| 	if (have_cpuid_p()) {
 | |
| 		/* 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;
 | |
| 		}
 | |
| 
 | |
| 		/* 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);
 | |
| 			}
 | |
| 		}
 | |
| 
 | |
| 	}
 | |
| 
 | |
| }
 | |
| 
 | |
| /* 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;
 | |
| 	c->x86_clflush_size = 32;
 | |
| 
 | |
| 	if (!have_cpuid_p())
 | |
| 		return;
 | |
| 
 | |
| 	cpu_detect(c);
 | |
| 
 | |
| 	get_cpu_vendor(c, 1);
 | |
| 
 | |
| 	switch (c->x86_vendor) {
 | |
| 	case X86_VENDOR_AMD:
 | |
| 		early_init_amd(c);
 | |
| 		break;
 | |
| 	case X86_VENDOR_INTEL:
 | |
| 		early_init_intel(c);
 | |
| 		break;
 | |
| 	}
 | |
| 
 | |
| 	early_get_cap(c);
 | |
| }
 | |
| 
 | |
| static void __cpuinit generic_identify(struct cpuinfo_x86 * c)
 | |
| {
 | |
| 	u32 tfms, xlvl;
 | |
| 	unsigned int ebx;
 | |
| 
 | |
| 	if (have_cpuid_p()) {
 | |
| 		/* Get vendor name */
 | |
| 		cpuid(0x00000000, (unsigned int *)&c->cpuid_level,
 | |
| 		      (unsigned int *)&c->x86_vendor_id[0],
 | |
| 		      (unsigned int *)&c->x86_vendor_id[8],
 | |
| 		      (unsigned 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);
 | |
| 	}
 | |
| 
 | |
| #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...
 | |
|  */
 | |
| 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);
 | |
| 
 | |
| 	if (this_cpu->c_identify)
 | |
| 		this_cpu->c_identify(c);
 | |
| 
 | |
| 	/*
 | |
| 	 * 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."
 | |
| 	 */
 | |
| 
 | |
| 	/* 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);
 | |
| 	}
 | |
| 
 | |
| 	/*
 | |
| 	 * 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];
 | |
| 	}
 | |
| 
 | |
| 	/* Clear all flags overriden by options */
 | |
| 	for (i = 0; i < NCAPINTS; i++)
 | |
| 		c->x86_capability[i] &= ~cleared_cpu_caps[i];
 | |
| 
 | |
| 	/* Init Machine Check Exception if available. */
 | |
| 	mcheck_init(c);
 | |
| 
 | |
| 	select_idle_routine(c);
 | |
| }
 | |
| 
 | |
| void __init identify_boot_cpu(void)
 | |
| {
 | |
| 	identify_cpu(&boot_cpu_data);
 | |
| 	sysenter_setup();
 | |
| 	enable_sep_cpu();
 | |
| }
 | |
| 
 | |
| 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
 | |
| 
 | |
| static __init int setup_noclflush(char *arg)
 | |
| {
 | |
| 	setup_clear_cpu_cap(X86_FEATURE_CLFLSH);
 | |
| 	return 1;
 | |
| }
 | |
| __setup("noclflush", setup_noclflush);
 | |
| 
 | |
| 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");
 | |
| }
 | |
| 
 | |
| static __init int setup_disablecpuid(char *arg)
 | |
| {
 | |
| 	int bit;
 | |
| 	if (get_option(&arg, &bit) && bit < NCAPINTS*32)
 | |
| 		setup_clear_cpu_cap(bit);
 | |
| 	else
 | |
| 		return 0;
 | |
| 	return 1;
 | |
| }
 | |
| __setup("clearcpuid=", setup_disablecpuid);
 | |
| 
 | |
| 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.
 | |
|  */
 | |
| 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();
 | |
| }
 | |
| 
 | |
| /* Make sure %fs is initialized properly in idle threads */
 | |
| struct pt_regs * __cpuinit idle_regs(struct pt_regs *regs)
 | |
| {
 | |
| 	memset(regs, 0, sizeof(struct pt_regs));
 | |
| 	regs->fs = __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 desc_ptr 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);
 | |
| 
 | |
| 	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_sp0(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
 |