linux/arch/x86/kernel/cpu/amd.c

#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/mm.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/apic.h>

#include <mach_apic.h>
#include "cpu.h"

/*
 *	B step AMD K6 before B 9730xxxx have hardware bugs that can cause
 *	misexecution of code under Linux. Owners of such processors should
 *	contact AMD for precise details and a CPU swap.
 *
 *	See	http://www.multimania.com/poulot/k6bug.html
 *		http://www.amd.com/K6/k6docs/revgd.html
 *
 *	The following test is erm.. interesting. AMD neglected to up
 *	the chip setting when fixing the bug but they also tweaked some
 *	performance at the same time..
 */

extern void vide(void);
__asm__(".align 4\nvide: ret");

static void __cpuinit early_init_amd(struct cpuinfo_x86 *c)
{
	if (c->x86_power & (1<<8))
		set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);

	/*  Set MTRR capability flag if appropriate */
	if (c->x86_model == 13 || c->x86_model == 9 ||
	   (c->x86_model == 8 && c->x86_mask >= 8))
		set_cpu_cap(c, X86_FEATURE_K6_MTRR);
}

static void __cpuinit init_amd(struct cpuinfo_x86 *c)
{
	u32 l, h;
	int mbytes = num_physpages >> (20-PAGE_SHIFT);

#ifdef CONFIG_SMP
	unsigned long long value;

	/*
	 * Disable TLB flush filter by setting HWCR.FFDIS on K8
	 * bit 6 of msr C001_0015
	 *
	 * Errata 63 for SH-B3 steppings
	 * Errata 122 for all steppings (F+ have it disabled by default)
	 */
	if (c->x86 == 15) {
		rdmsrl(MSR_K7_HWCR, value);
		value |= 1 << 6;
		wrmsrl(MSR_K7_HWCR, value);
	}
#endif

	early_init_amd(c);

	/*
	 *	FIXME: We should handle the K5 here. Set up the write
	 *	range and also turn on MSR 83 bits 4 and 31 (write alloc,
	 *	no bus pipeline)
	 */

	/*
	 * Bit 31 in normal CPUID used for nonstandard 3DNow ID;
	 * 3DNow is IDd by bit 31 in extended CPUID (1*32+31) anyway
	 */
	clear_cpu_cap(c, 0*32+31);

	switch (c->x86) {
	case 4:
		/*
		 * General Systems BIOSen alias the cpu frequency registers
		 * of the Elan at 0x000df000. Unfortuantly, one of the Linux
		 * drivers subsequently pokes it, and changes the CPU speed.
		 * Workaround : Remove the unneeded alias.
		 */
#define CBAR		(0xfffc) /* Configuration Base Address  (32-bit) */
#define CBAR_ENB	(0x80000000)
#define CBAR_KEY	(0X000000CB)
			if (c->x86_model == 9 || c->x86_model == 10) {
				if (inl (CBAR) & CBAR_ENB)
					outl (0 | CBAR_KEY, CBAR);
			}
			break;
	case 5:
			if (c->x86_model < 6) {
				/* Based on AMD doc 20734R - June 2000 */
				if (c->x86_model == 0) {
					clear_cpu_cap(c, X86_FEATURE_APIC);
					set_cpu_cap(c, X86_FEATURE_PGE);
				}
				break;
			}

			if (c->x86_model == 6 && c->x86_mask == 1) {
				const int K6_BUG_LOOP = 1000000;
				int n;
				void (*f_vide)(void);
				unsigned long d, d2;

				printk(KERN_INFO "AMD K6 stepping B detected - ");

				/*
				 * It looks like AMD fixed the 2.6.2 bug and improved indirect
				 * calls at the same time.
				 */

				n = K6_BUG_LOOP;
				f_vide = vide;
				rdtscl(d);
				while (n--)
					f_vide();
				rdtscl(d2);
				d = d2-d;

				if (d > 20*K6_BUG_LOOP)
					printk("system stability may be impaired when more than 32 MB are used.\n");
				else
					printk("probably OK (after B9730xxxx).\n");
				printk(KERN_INFO "Please see http://membres.lycos.fr/poulot/k6bug.html\n");
			}

			/* K6 with old style WHCR */
			if (c->x86_model < 8 ||
			   (c->x86_model == 8 && c->x86_mask < 8)) {
				/* We can only write allocate on the low 508Mb */
				if (mbytes > 508)
					mbytes = 508;

				rdmsr(MSR_K6_WHCR, l, h);
				if ((l&0x0000FFFF) == 0) {
					unsigned long flags;
					l = (1<<0)|((mbytes/4)<<1);
					local_irq_save(flags);
					wbinvd();
					wrmsr(MSR_K6_WHCR, l, h);
					local_irq_restore(flags);
					printk(KERN_INFO "Enabling old style K6 write allocation for %d Mb\n",
						mbytes);
				}
				break;
			}

			if ((c->x86_model == 8 && c->x86_mask > 7) ||
			     c->x86_model == 9 || c->x86_model == 13) {
				/* The more serious chips .. */

				if (mbytes > 4092)
					mbytes = 4092;

				rdmsr(MSR_K6_WHCR, l, h);
				if ((l&0xFFFF0000) == 0) {
					unsigned long flags;
					l = ((mbytes>>2)<<22)|(1<<16);
					local_irq_save(flags);
					wbinvd();
					wrmsr(MSR_K6_WHCR, l, h);
					local_irq_restore(flags);
					printk(KERN_INFO "Enabling new style K6 write allocation for %d Mb\n",
						mbytes);
				}

				break;
			}

			if (c->x86_model == 10) {
				/* AMD Geode LX is model 10 */
				/* placeholder for any needed mods */
				break;
			}
			break;
	case 6: /* An Athlon/Duron */

			/*
			 * Bit 15 of Athlon specific MSR 15, needs to be 0
			 * to enable SSE on Palomino/Morgan/Barton CPU's.
			 * If the BIOS didn't enable it already, enable it here.
			 */
			if (c->x86_model >= 6 && c->x86_model <= 10) {
				if (!cpu_has(c, X86_FEATURE_XMM)) {
					printk(KERN_INFO "Enabling disabled K7/SSE Support.\n");
					rdmsr(MSR_K7_HWCR, l, h);
					l &= ~0x00008000;
					wrmsr(MSR_K7_HWCR, l, h);
					set_cpu_cap(c, X86_FEATURE_XMM);
				}
			}

			/*
			 * It's been determined by AMD that Athlons since model 8 stepping 1
			 * are more robust with CLK_CTL set to 200xxxxx instead of 600xxxxx
			 * As per AMD technical note 27212 0.2
			 */
			if ((c->x86_model == 8 && c->x86_mask >= 1) || (c->x86_model > 8)) {
				rdmsr(MSR_K7_CLK_CTL, l, h);
				if ((l & 0xfff00000) != 0x20000000) {
					printk ("CPU: CLK_CTL MSR was %x. Reprogramming to %x\n", l,
						((l & 0x000fffff)|0x20000000));
					wrmsr(MSR_K7_CLK_CTL, (l & 0x000fffff)|0x20000000, h);
				}
			}
			break;
	}

	switch (c->x86) {
	case 15:
	/* Use K8 tuning for Fam10h and Fam11h */
	case 0x10:
	case 0x11:
		set_cpu_cap(c, X86_FEATURE_K8);
		break;
	case 6:
		set_cpu_cap(c, X86_FEATURE_K7);
		break;
	}
	if (c->x86 >= 6)
		set_cpu_cap(c, X86_FEATURE_FXSAVE_LEAK);

	display_cacheinfo(c);

	if (cpuid_eax(0x80000000) >= 0x80000008)
		c->x86_max_cores = (cpuid_ecx(0x80000008) & 0xff) + 1;

#ifdef CONFIG_X86_HT
	/*
	 * On a AMD multi core setup the lower bits of the APIC id
	 * distinguish the cores.
	 */
	if (c->x86_max_cores > 1) {
		int cpu = smp_processor_id();
		unsigned bits = (cpuid_ecx(0x80000008) >> 12) & 0xf;

		if (bits == 0) {
			while ((1 << bits) < c->x86_max_cores)
				bits++;
		}
		c->cpu_core_id = c->phys_proc_id & ((1<<bits)-1);
		c->phys_proc_id >>= bits;
		printk(KERN_INFO "CPU %d(%d) -> Core %d\n",
		       cpu, c->x86_max_cores, c->cpu_core_id);
	}
#endif

	if (cpuid_eax(0x80000000) >= 0x80000006) {
		if ((c->x86 == 0x10) && (cpuid_edx(0x80000006) & 0xf000))
			num_cache_leaves = 4;
		else
			num_cache_leaves = 3;
	}

	/* K6s reports MCEs but don't actually have all the MSRs */
	if (c->x86 < 6)
		clear_cpu_cap(c, X86_FEATURE_MCE);

	if (cpu_has_xmm2)
		set_cpu_cap(c, X86_FEATURE_MFENCE_RDTSC);
}

static unsigned int __cpuinit amd_size_cache(struct cpuinfo_x86 *c, unsigned int size)
{
	/* AMD errata T13 (order #21922) */
	if ((c->x86 == 6)) {
		if (c->x86_model == 3 && c->x86_mask == 0)	/* Duron Rev A0 */
			size = 64;
		if (c->x86_model == 4 &&
		    (c->x86_mask == 0 || c->x86_mask == 1))	/* Tbird rev A1/A2 */
			size = 256;
	}
	return size;
}

static struct cpu_dev amd_cpu_dev __cpuinitdata = {
	.c_vendor	= "AMD",
	.c_ident	= { "AuthenticAMD" },
	.c_models = {
		{ .vendor = X86_VENDOR_AMD, .family = 4, .model_names =
		  {
			  [3] = "486 DX/2",
			  [7] = "486 DX/2-WB",
			  [8] = "486 DX/4",
			  [9] = "486 DX/4-WB",
			  [14] = "Am5x86-WT",
			  [15] = "Am5x86-WB"
		  }
		},
	},
	.c_early_init   = early_init_amd,
	.c_init		= init_amd,
	.c_size_cache	= amd_size_cache,
	.c_x86_vendor	= X86_VENDOR_AMD,
};

cpu_dev_register(amd_cpu_dev);