main.c

linux内核源码

			     mtrr_attrib_to_str(type));
			goto out;
		}
		if (increment)
			++usage_table[i];
		error = i;
		goto out;
	}
	/*  Search for an empty MTRR  */
	i = mtrr_if->get_free_region(base, size, replace);
	if (i >= 0) {
		set_mtrr(i, base, size, type);
		if (likely(replace < 0))
			usage_table[i] = 1;
		else {
			usage_table[i] = usage_table[replace] + !!increment;
			if (unlikely(replace != i)) {
				set_mtrr(replace, 0, 0, 0);
				usage_table[replace] = 0;
			}
		}
	} else
		printk(KERN_INFO "mtrr: no more MTRRs available\n");
	error = i;
 out:
	mutex_unlock(&mtrr_mutex);
	unlock_cpu_hotplug();
	return error;
}

static int mtrr_check(unsigned long base, unsigned long size)
{
	if ((base & (PAGE_SIZE - 1)) || (size & (PAGE_SIZE - 1))) {
		printk(KERN_WARNING
			"mtrr: size and base must be multiples of 4 kiB\n");
		printk(KERN_DEBUG
			"mtrr: size: 0x%lx  base: 0x%lx\n", size, base);
		dump_stack();
		return -1;
	}
	return 0;
}

/**
 *	mtrr_add - Add a memory type region
 *	@base: Physical base address of region
 *	@size: Physical size of region
 *	@type: Type of MTRR desired
 *	@increment: If this is true do usage counting on the region
 *
 *	Memory type region registers control the caching on newer Intel and
 *	non Intel processors. This function allows drivers to request an
 *	MTRR is added. The details and hardware specifics of each processor's
 *	implementation are hidden from the caller, but nevertheless the 
 *	caller should expect to need to provide a power of two size on an
 *	equivalent power of two boundary.
 *
 *	If the region cannot be added either because all regions are in use
 *	or the CPU cannot support it a negative value is returned. On success
 *	the register number for this entry is returned, but should be treated
 *	as a cookie only.
 *
 *	On a multiprocessor machine the changes are made to all processors.
 *	This is required on x86 by the Intel processors.
 *
 *	The available types are
 *
 *	%MTRR_TYPE_UNCACHABLE	-	No caching
 *
 *	%MTRR_TYPE_WRBACK	-	Write data back in bursts whenever
 *
 *	%MTRR_TYPE_WRCOMB	-	Write data back soon but allow bursts
 *
 *	%MTRR_TYPE_WRTHROUGH	-	Cache reads but not writes
 *
 *	BUGS: Needs a quiet flag for the cases where drivers do not mind
 *	failures and do not wish system log messages to be sent.
 */

int
mtrr_add(unsigned long base, unsigned long size, unsigned int type,
	 char increment)
{
	if (mtrr_check(base, size))
		return -EINVAL;
	return mtrr_add_page(base >> PAGE_SHIFT, size >> PAGE_SHIFT, type,
			     increment);
}

/**
 *	mtrr_del_page - delete a memory type region
 *	@reg: Register returned by mtrr_add
 *	@base: Physical base address
 *	@size: Size of region
 *
 *	If register is supplied then base and size are ignored. This is
 *	how drivers should call it.
 *
 *	Releases an MTRR region. If the usage count drops to zero the 
 *	register is freed and the region returns to default state.
 *	On success the register is returned, on failure a negative error
 *	code.
 */

int mtrr_del_page(int reg, unsigned long base, unsigned long size)
{
	int i, max;
	mtrr_type ltype;
	unsigned long lbase, lsize;
	int error = -EINVAL;

	if (!mtrr_if)
		return -ENXIO;

	max = num_var_ranges;
	/* No CPU hotplug when we change MTRR entries */
	lock_cpu_hotplug();
	mutex_lock(&mtrr_mutex);
	if (reg < 0) {
		/*  Search for existing MTRR  */
		for (i = 0; i < max; ++i) {
			mtrr_if->get(i, &lbase, &lsize, &ltype);
			if (lbase == base && lsize == size) {
				reg = i;
				break;
			}
		}
		if (reg < 0) {
			printk(KERN_DEBUG "mtrr: no MTRR for %lx000,%lx000 found\n", base,
			       size);
			goto out;
		}
	}
	if (reg >= max) {
		printk(KERN_WARNING "mtrr: register: %d too big\n", reg);
		goto out;
	}
	if (is_cpu(CYRIX) && !use_intel()) {
		if ((reg == 3) && arr3_protected) {
			printk(KERN_WARNING "mtrr: ARR3 cannot be changed\n");
			goto out;
		}
	}
	mtrr_if->get(reg, &lbase, &lsize, &ltype);
	if (lsize < 1) {
		printk(KERN_WARNING "mtrr: MTRR %d not used\n", reg);
		goto out;
	}
	if (usage_table[reg] < 1) {
		printk(KERN_WARNING "mtrr: reg: %d has count=0\n", reg);
		goto out;
	}
	if (--usage_table[reg] < 1)
		set_mtrr(reg, 0, 0, 0);
	error = reg;
 out:
	mutex_unlock(&mtrr_mutex);
	unlock_cpu_hotplug();
	return error;
}
/**
 *	mtrr_del - delete a memory type region
 *	@reg: Register returned by mtrr_add
 *	@base: Physical base address
 *	@size: Size of region
 *
 *	If register is supplied then base and size are ignored. This is
 *	how drivers should call it.
 *
 *	Releases an MTRR region. If the usage count drops to zero the 
 *	register is freed and the region returns to default state.
 *	On success the register is returned, on failure a negative error
 *	code.
 */

int
mtrr_del(int reg, unsigned long base, unsigned long size)
{
	if (mtrr_check(base, size))
		return -EINVAL;
	return mtrr_del_page(reg, base >> PAGE_SHIFT, size >> PAGE_SHIFT);
}

EXPORT_SYMBOL(mtrr_add);
EXPORT_SYMBOL(mtrr_del);

/* HACK ALERT!
 * These should be called implicitly, but we can't yet until all the initcall
 * stuff is done...
 */
extern void amd_init_mtrr(void);
extern void cyrix_init_mtrr(void);
extern void centaur_init_mtrr(void);

static void __init init_ifs(void)
{
#ifndef CONFIG_X86_64
	amd_init_mtrr();
	cyrix_init_mtrr();
	centaur_init_mtrr();
#endif
}

/* The suspend/resume methods are only for CPU without MTRR. CPU using generic
 * MTRR driver doesn't require this
 */
struct mtrr_value {
	mtrr_type	ltype;
	unsigned long	lbase;
	unsigned long	lsize;
};

static struct mtrr_value * mtrr_state;

static int mtrr_save(struct sys_device * sysdev, pm_message_t state)
{
	int i;
	int size = num_var_ranges * sizeof(struct mtrr_value);

	mtrr_state = kzalloc(size,GFP_ATOMIC);
	if (!mtrr_state)
		return -ENOMEM;

	for (i = 0; i < num_var_ranges; i++) {
		mtrr_if->get(i,
			     &mtrr_state[i].lbase,
			     &mtrr_state[i].lsize,
			     &mtrr_state[i].ltype);
	}
	return 0;
}

static int mtrr_restore(struct sys_device * sysdev)
{
	int i;

	for (i = 0; i < num_var_ranges; i++) {
		if (mtrr_state[i].lsize) 
			set_mtrr(i,
				 mtrr_state[i].lbase,
				 mtrr_state[i].lsize,
				 mtrr_state[i].ltype);
	}
	kfree(mtrr_state);
	return 0;
}



static struct sysdev_driver mtrr_sysdev_driver = {
	.suspend	= mtrr_save,
	.resume		= mtrr_restore,
};


/**
 * mtrr_bp_init - initialize mtrrs on the boot CPU
 *
 * This needs to be called early; before any of the other CPUs are 
 * initialized (i.e. before smp_init()).
 * 
 */
void __init mtrr_bp_init(void)
{
	init_ifs();

	if (cpu_has_mtrr) {
		mtrr_if = &generic_mtrr_ops;
		size_or_mask = 0xff000000;	/* 36 bits */
		size_and_mask = 0x00f00000;

		/* This is an AMD specific MSR, but we assume(hope?) that
		   Intel will implement it to when they extend the address
		   bus of the Xeon. */
		if (cpuid_eax(0x80000000) >= 0x80000008) {
			u32 phys_addr;
			phys_addr = cpuid_eax(0x80000008) & 0xff;
			/* CPUID workaround for Intel 0F33/0F34 CPU */
			if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
			    boot_cpu_data.x86 == 0xF &&
			    boot_cpu_data.x86_model == 0x3 &&
			    (boot_cpu_data.x86_mask == 0x3 ||
			     boot_cpu_data.x86_mask == 0x4))
				phys_addr = 36;

			size_or_mask = ~((1ULL << (phys_addr - PAGE_SHIFT)) - 1);
			size_and_mask = ~size_or_mask & 0xfffff00000ULL;
		} else if (boot_cpu_data.x86_vendor == X86_VENDOR_CENTAUR &&
			   boot_cpu_data.x86 == 6) {
			/* VIA C* family have Intel style MTRRs, but
			   don't support PAE */
			size_or_mask = 0xfff00000;	/* 32 bits */
			size_and_mask = 0;
		}
	} else {
		switch (boot_cpu_data.x86_vendor) {
		case X86_VENDOR_AMD:
			if (cpu_has_k6_mtrr) {
				/* Pre-Athlon (K6) AMD CPU MTRRs */
				mtrr_if = mtrr_ops[X86_VENDOR_AMD];
				size_or_mask = 0xfff00000;	/* 32 bits */
				size_and_mask = 0;
			}
			break;
		case X86_VENDOR_CENTAUR:
			if (cpu_has_centaur_mcr) {
				mtrr_if = mtrr_ops[X86_VENDOR_CENTAUR];
				size_or_mask = 0xfff00000;	/* 32 bits */
				size_and_mask = 0;
			}
			break;
		case X86_VENDOR_CYRIX:
			if (cpu_has_cyrix_arr) {
				mtrr_if = mtrr_ops[X86_VENDOR_CYRIX];
				size_or_mask = 0xfff00000;	/* 32 bits */
				size_and_mask = 0;
			}
			break;
		default:
			break;
		}
	}

	if (mtrr_if) {
		set_num_var_ranges();
		init_table();
		if (use_intel())
			get_mtrr_state();
	}
}

void mtrr_ap_init(void)
{
	unsigned long flags;

	if (!mtrr_if || !use_intel())
		return;
	/*
	 * Ideally we should hold mtrr_mutex here to avoid mtrr entries changed,
	 * but this routine will be called in cpu boot time, holding the lock
	 * breaks it. This routine is called in two cases: 1.very earily time
	 * of software resume, when there absolutely isn't mtrr entry changes;
	 * 2.cpu hotadd time. We let mtrr_add/del_page hold cpuhotplug lock to
	 * prevent mtrr entry changes
	 */
	local_irq_save(flags);

	mtrr_if->set_all();

	local_irq_restore(flags);
}

/**
 * Save current fixed-range MTRR state of the BSP
 */
void mtrr_save_state(void)
{
	smp_call_function_single(0, mtrr_save_fixed_ranges, NULL, 1, 1);
}

static int __init mtrr_init_finialize(void)
{
	if (!mtrr_if)
		return 0;
	if (use_intel())
		mtrr_state_warn();
	else {
		/* The CPUs haven't MTRR and seem to not support SMP. They have
		 * specific drivers, we use a tricky method to support
		 * suspend/resume for them.
		 * TBD: is there any system with such CPU which supports
		 * suspend/resume?  if no, we should remove the code.
		 */
		sysdev_driver_register(&cpu_sysdev_class,
			&mtrr_sysdev_driver);
	}
	return 0;
}
subsys_initcall(mtrr_init_finialize);