pat.c 24.7 KB
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/*
 * Handle caching attributes in page tables (PAT)
 *
 * Authors: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
 *          Suresh B Siddha <suresh.b.siddha@intel.com>
 *
 * Loosely based on earlier PAT patchset from Eric Biederman and Andi Kleen.
 */

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#include <linux/seq_file.h>
#include <linux/bootmem.h>
#include <linux/debugfs.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/gfp.h>
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#include <linux/mm.h>
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#include <linux/fs.h>
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#include <linux/rbtree.h>
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#include <asm/cacheflush.h>
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#include <asm/processor.h>
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#include <asm/tlbflush.h>
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#include <asm/x86_init.h>
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#include <asm/pgtable.h>
#include <asm/fcntl.h>
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#include <asm/e820.h>
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#include <asm/mtrr.h>
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#include <asm/page.h>
#include <asm/msr.h>
#include <asm/pat.h>
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#include <asm/io.h>
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#ifdef CONFIG_X86_PAT
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int __read_mostly pat_enabled = 1;
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static inline void pat_disable(const char *reason)
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{
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	pat_enabled = 0;
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	printk(KERN_INFO "%s\n", reason);
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}

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static int __init nopat(char *str)
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{
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	pat_disable("PAT support disabled.");
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	return 0;
}
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early_param("nopat", nopat);
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#else
static inline void pat_disable(const char *reason)
{
	(void)reason;
}
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#endif

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static int debug_enable;
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static int __init pat_debug_setup(char *str)
{
	debug_enable = 1;
	return 0;
}
__setup("debugpat", pat_debug_setup);

#define dprintk(fmt, arg...) \
	do { if (debug_enable) printk(KERN_INFO fmt, ##arg); } while (0)


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static u64 __read_mostly boot_pat_state;
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enum {
	PAT_UC = 0,		/* uncached */
	PAT_WC = 1,		/* Write combining */
	PAT_WT = 4,		/* Write Through */
	PAT_WP = 5,		/* Write Protected */
	PAT_WB = 6,		/* Write Back (default) */
	PAT_UC_MINUS = 7,	/* UC, but can be overriden by MTRR */
};

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#define PAT(x, y)	((u64)PAT_ ## y << ((x)*8))
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void pat_init(void)
{
	u64 pat;
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	bool boot_cpu = !boot_pat_state;
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	if (!pat_enabled)
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		return;

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	if (!cpu_has_pat) {
		if (!boot_pat_state) {
			pat_disable("PAT not supported by CPU.");
			return;
		} else {
			/*
			 * If this happens we are on a secondary CPU, but
			 * switched to PAT on the boot CPU. We have no way to
			 * undo PAT.
			 */
			printk(KERN_ERR "PAT enabled, "
			       "but not supported by secondary CPU\n");
			BUG();
		}
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	}
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	/* Set PWT to Write-Combining. All other bits stay the same */
	/*
	 * PTE encoding used in Linux:
	 *      PAT
	 *      |PCD
	 *      ||PWT
	 *      |||
	 *      000 WB		_PAGE_CACHE_WB
	 *      001 WC		_PAGE_CACHE_WC
	 *      010 UC-		_PAGE_CACHE_UC_MINUS
	 *      011 UC		_PAGE_CACHE_UC
	 * PAT bit unused
	 */
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	pat = PAT(0, WB) | PAT(1, WC) | PAT(2, UC_MINUS) | PAT(3, UC) |
	      PAT(4, WB) | PAT(5, WC) | PAT(6, UC_MINUS) | PAT(7, UC);
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	/* Boot CPU check */
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	if (!boot_pat_state)
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		rdmsrl(MSR_IA32_CR_PAT, boot_pat_state);

	wrmsrl(MSR_IA32_CR_PAT, pat);
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	if (boot_cpu)
		printk(KERN_INFO "x86 PAT enabled: cpu %d, old 0x%Lx, new 0x%Lx\n",
		       smp_processor_id(), boot_pat_state, pat);
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}

#undef PAT

static char *cattr_name(unsigned long flags)
{
	switch (flags & _PAGE_CACHE_MASK) {
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	case _PAGE_CACHE_UC:		return "uncached";
	case _PAGE_CACHE_UC_MINUS:	return "uncached-minus";
	case _PAGE_CACHE_WB:		return "write-back";
	case _PAGE_CACHE_WC:		return "write-combining";
	default:			return "broken";
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	}
}

/*
 * The global memtype list keeps track of memory type for specific
 * physical memory areas. Conflicting memory types in different
 * mappings can cause CPU cache corruption. To avoid this we keep track.
 *
 * The list is sorted based on starting address and can contain multiple
 * entries for each address (this allows reference counting for overlapping
 * areas). All the aliases have the same cache attributes of course.
 * Zero attributes are represented as holes.
 *
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 * The data structure is a list that is also organized as an rbtree
 * sorted on the start address of memtype range.
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 *
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 * memtype_lock protects both the linear list and rbtree.
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 */

struct memtype {
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	u64			start;
	u64			end;
	unsigned long		type;
	struct list_head	nd;
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	struct rb_node		rb;
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};

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static struct rb_root memtype_rbroot = RB_ROOT;
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static LIST_HEAD(memtype_list);
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static DEFINE_SPINLOCK(memtype_lock);	/* protects memtype list */
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static struct memtype *memtype_rb_search(struct rb_root *root, u64 start)
{
	struct rb_node *node = root->rb_node;
	struct memtype *last_lower = NULL;

	while (node) {
		struct memtype *data = container_of(node, struct memtype, rb);

		if (data->start < start) {
			last_lower = data;
			node = node->rb_right;
		} else if (data->start > start) {
			node = node->rb_left;
		} else
			return data;
	}

	/* Will return NULL if there is no entry with its start <= start */
	return last_lower;
}

static void memtype_rb_insert(struct rb_root *root, struct memtype *data)
{
	struct rb_node **new = &(root->rb_node);
	struct rb_node *parent = NULL;

	while (*new) {
		struct memtype *this = container_of(*new, struct memtype, rb);

		parent = *new;
		if (data->start <= this->start)
			new = &((*new)->rb_left);
		else if (data->start > this->start)
			new = &((*new)->rb_right);
	}

	rb_link_node(&data->rb, parent, new);
	rb_insert_color(&data->rb, root);
}

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/*
 * Does intersection of PAT memory type and MTRR memory type and returns
 * the resulting memory type as PAT understands it.
 * (Type in pat and mtrr will not have same value)
 * The intersection is based on "Effective Memory Type" tables in IA-32
 * SDM vol 3a
 */
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static unsigned long pat_x_mtrr_type(u64 start, u64 end, unsigned long req_type)
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{
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	/*
	 * Look for MTRR hint to get the effective type in case where PAT
	 * request is for WB.
	 */
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	if (req_type == _PAGE_CACHE_WB) {
		u8 mtrr_type;

		mtrr_type = mtrr_type_lookup(start, end);
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		if (mtrr_type != MTRR_TYPE_WRBACK)
			return _PAGE_CACHE_UC_MINUS;

		return _PAGE_CACHE_WB;
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	}

	return req_type;
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}

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static int
chk_conflict(struct memtype *new, struct memtype *entry, unsigned long *type)
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{
	if (new->type != entry->type) {
		if (type) {
			new->type = entry->type;
			*type = entry->type;
		} else
			goto conflict;
	}

	 /* check overlaps with more than one entry in the list */
	list_for_each_entry_continue(entry, &memtype_list, nd) {
		if (new->end <= entry->start)
			break;
		else if (new->type != entry->type)
			goto conflict;
	}
	return 0;

 conflict:
	printk(KERN_INFO "%s:%d conflicting memory types "
	       "%Lx-%Lx %s<->%s\n", current->comm, current->pid, new->start,
	       new->end, cattr_name(new->type), cattr_name(entry->type));
	return -EBUSY;
}

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static int pat_pagerange_is_ram(unsigned long start, unsigned long end)
{
	int ram_page = 0, not_rampage = 0;
	unsigned long page_nr;

	for (page_nr = (start >> PAGE_SHIFT); page_nr < (end >> PAGE_SHIFT);
	     ++page_nr) {
		/*
		 * For legacy reasons, physical address range in the legacy ISA
		 * region is tracked as non-RAM. This will allow users of
		 * /dev/mem to map portions of legacy ISA region, even when
		 * some of those portions are listed(or not even listed) with
		 * different e820 types(RAM/reserved/..)
		 */
		if (page_nr >= (ISA_END_ADDRESS >> PAGE_SHIFT) &&
		    page_is_ram(page_nr))
			ram_page = 1;
		else
			not_rampage = 1;

		if (ram_page == not_rampage)
			return -1;
	}

	return ram_page;
}

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/*
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 * For RAM pages, we use page flags to mark the pages with appropriate type.
 * Here we do two pass:
 * - Find the memtype of all the pages in the range, look for any conflicts
 * - In case of no conflicts, set the new memtype for pages in the range
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 *
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 * Caller must hold memtype_lock for atomicity.
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 */
static int reserve_ram_pages_type(u64 start, u64 end, unsigned long req_type,
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				  unsigned long *new_type)
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{
	struct page *page;
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	u64 pfn;

	if (req_type == _PAGE_CACHE_UC) {
		/* We do not support strong UC */
		WARN_ON_ONCE(1);
		req_type = _PAGE_CACHE_UC_MINUS;
	}
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	for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) {
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		unsigned long type;
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		page = pfn_to_page(pfn);
		type = get_page_memtype(page);
		if (type != -1) {
			printk(KERN_INFO "reserve_ram_pages_type failed "
				"0x%Lx-0x%Lx, track 0x%lx, req 0x%lx\n",
				start, end, type, req_type);
			if (new_type)
				*new_type = type;

			return -EBUSY;
		}
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	}

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	if (new_type)
		*new_type = req_type;

	for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) {
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		page = pfn_to_page(pfn);
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		set_page_memtype(page, req_type);
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	}
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	return 0;
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}

static int free_ram_pages_type(u64 start, u64 end)
{
	struct page *page;
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	u64 pfn;
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	for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) {
		page = pfn_to_page(pfn);
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		set_page_memtype(page, -1);
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	}
	return 0;
}

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/*
 * req_type typically has one of the:
 * - _PAGE_CACHE_WB
 * - _PAGE_CACHE_WC
 * - _PAGE_CACHE_UC_MINUS
 * - _PAGE_CACHE_UC
 *
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 * If new_type is NULL, function will return an error if it cannot reserve the
 * region with req_type. If new_type is non-NULL, function will return
 * available type in new_type in case of no error. In case of any error
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 * it will return a negative return value.
 */
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int reserve_memtype(u64 start, u64 end, unsigned long req_type,
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		    unsigned long *new_type)
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{
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	struct memtype *new, *entry;
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	unsigned long actual_type;
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	struct list_head *where;
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	int is_range_ram;
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	int err = 0;
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	BUG_ON(start >= end); /* end is exclusive */
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	if (!pat_enabled) {
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		/* This is identical to page table setting without PAT */
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		if (new_type) {
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			if (req_type == _PAGE_CACHE_WC)
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				*new_type = _PAGE_CACHE_UC_MINUS;
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			else
				*new_type = req_type & _PAGE_CACHE_MASK;
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		}
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		return 0;
	}

	/* Low ISA region is always mapped WB in page table. No need to track */
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	if (x86_platform.is_untracked_pat_range(start, end)) {
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		if (new_type)
			*new_type = _PAGE_CACHE_WB;
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		return 0;
	}

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	/*
	 * Call mtrr_lookup to get the type hint. This is an
	 * optimization for /dev/mem mmap'ers into WB memory (BIOS
	 * tools and ACPI tools). Use WB request for WB memory and use
	 * UC_MINUS otherwise.
	 */
	actual_type = pat_x_mtrr_type(start, end, req_type & _PAGE_CACHE_MASK);
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	if (new_type)
		*new_type = actual_type;

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	is_range_ram = pat_pagerange_is_ram(start, end);
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	if (is_range_ram == 1) {

		spin_lock(&memtype_lock);
		err = reserve_ram_pages_type(start, end, req_type, new_type);
		spin_unlock(&memtype_lock);

		return err;
	} else if (is_range_ram < 0) {
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		return -EINVAL;
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	}
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	new  = kmalloc(sizeof(struct memtype), GFP_KERNEL);
	if (!new)
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		return -ENOMEM;

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	new->start	= start;
	new->end	= end;
	new->type	= actual_type;
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	spin_lock(&memtype_lock);

	/* Search for existing mapping that overlaps the current range */
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	where = NULL;
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	list_for_each_entry(entry, &memtype_list, nd) {
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		if (end <= entry->start) {
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			where = entry->nd.prev;
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			break;
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		} else if (start <= entry->start) { /* end > entry->start */
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			err = chk_conflict(new, entry, new_type);
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			if (!err) {
				dprintk("Overlap at 0x%Lx-0x%Lx\n",
					entry->start, entry->end);
				where = entry->nd.prev;
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			}
			break;
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		} else if (start < entry->end) { /* start > entry->start */
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			err = chk_conflict(new, entry, new_type);
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			if (!err) {
				dprintk("Overlap at 0x%Lx-0x%Lx\n",
					entry->start, entry->end);
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				/*
				 * Move to right position in the linked
				 * list to add this new entry
				 */
				list_for_each_entry_continue(entry,
							&memtype_list, nd) {
					if (start <= entry->start) {
						where = entry->nd.prev;
						break;
					}
				}
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			}
			break;
		}
	}

	if (err) {
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		printk(KERN_INFO "reserve_memtype failed 0x%Lx-0x%Lx, "
		       "track %s, req %s\n",
		       start, end, cattr_name(new->type), cattr_name(req_type));
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		kfree(new);
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		spin_unlock(&memtype_lock);
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		return err;
	}

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	if (where)
		list_add(&new->nd, where);
	else
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		list_add_tail(&new->nd, &memtype_list);
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	memtype_rb_insert(&memtype_rbroot, new);

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	spin_unlock(&memtype_lock);
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	dprintk("reserve_memtype added 0x%Lx-0x%Lx, track %s, req %s, ret %s\n",
		start, end, cattr_name(new->type), cattr_name(req_type),
		new_type ? cattr_name(*new_type) : "-");

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	return err;
}

int free_memtype(u64 start, u64 end)
{
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	struct memtype *entry, *saved_entry;
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	int err = -EINVAL;
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	int is_range_ram;
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	if (!pat_enabled)
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		return 0;

	/* Low ISA region is always mapped WB. No need to track */
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	if (x86_platform.is_untracked_pat_range(start, end))
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		return 0;

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	is_range_ram = pat_pagerange_is_ram(start, end);
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	if (is_range_ram == 1) {

		spin_lock(&memtype_lock);
		err = free_ram_pages_type(start, end);
		spin_unlock(&memtype_lock);

		return err;
	} else if (is_range_ram < 0) {
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		return -EINVAL;
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	}
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	spin_lock(&memtype_lock);
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	entry = memtype_rb_search(&memtype_rbroot, start);
	if (unlikely(entry == NULL))
		goto unlock_ret;

	/*
	 * Saved entry points to an entry with start same or less than what
	 * we searched for. Now go through the list in both directions to look
	 * for the entry that matches with both start and end, with list stored
	 * in sorted start address
	 */
	saved_entry = entry;
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	list_for_each_entry_from(entry, &memtype_list, nd) {
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		if (entry->start == start && entry->end == end) {
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			rb_erase(&entry->rb, &memtype_rbroot);
			list_del(&entry->nd);
			kfree(entry);
			err = 0;
			break;
		} else if (entry->start > start) {
			break;
		}
	}

	if (!err)
		goto unlock_ret;
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	entry = saved_entry;
	list_for_each_entry_reverse(entry, &memtype_list, nd) {
		if (entry->start == start && entry->end == end) {
			rb_erase(&entry->rb, &memtype_rbroot);
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			list_del(&entry->nd);
			kfree(entry);
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			err = 0;
			break;
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		} else if (entry->start < start) {
			break;
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		}
	}
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unlock_ret:
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	spin_unlock(&memtype_lock);

	if (err) {
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		printk(KERN_INFO "%s:%d freeing invalid memtype %Lx-%Lx\n",
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			current->comm, current->pid, start, end);
	}
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	dprintk("free_memtype request 0x%Lx-0x%Lx\n", start, end);
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	return err;
}

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/**
 * lookup_memtype - Looksup the memory type for a physical address
 * @paddr: physical address of which memory type needs to be looked up
 *
 * Only to be called when PAT is enabled
 *
 * Returns _PAGE_CACHE_WB, _PAGE_CACHE_WC, _PAGE_CACHE_UC_MINUS or
 * _PAGE_CACHE_UC
 */
static unsigned long lookup_memtype(u64 paddr)
{
	int rettype = _PAGE_CACHE_WB;
	struct memtype *entry;

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	if (x86_platform.is_untracked_pat_range(paddr, paddr + PAGE_SIZE))
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		return rettype;

	if (pat_pagerange_is_ram(paddr, paddr + PAGE_SIZE)) {
		struct page *page;
		spin_lock(&memtype_lock);
		page = pfn_to_page(paddr >> PAGE_SHIFT);
		rettype = get_page_memtype(page);
		spin_unlock(&memtype_lock);
		/*
		 * -1 from get_page_memtype() implies RAM page is in its
		 * default state and not reserved, and hence of type WB
		 */
		if (rettype == -1)
			rettype = _PAGE_CACHE_WB;

		return rettype;
	}

	spin_lock(&memtype_lock);

	entry = memtype_rb_search(&memtype_rbroot, paddr);
	if (entry != NULL)
		rettype = entry->type;
	else
		rettype = _PAGE_CACHE_UC_MINUS;

	spin_unlock(&memtype_lock);
	return rettype;
}

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/**
 * io_reserve_memtype - Request a memory type mapping for a region of memory
 * @start: start (physical address) of the region
 * @end: end (physical address) of the region
 * @type: A pointer to memtype, with requested type. On success, requested
 * or any other compatible type that was available for the region is returned
 *
 * On success, returns 0
 * On failure, returns non-zero
 */
int io_reserve_memtype(resource_size_t start, resource_size_t end,
			unsigned long *type)
{
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	resource_size_t size = end - start;
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	unsigned long req_type = *type;
	unsigned long new_type;
	int ret;

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	WARN_ON_ONCE(iomem_map_sanity_check(start, size));
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	ret = reserve_memtype(start, end, req_type, &new_type);
	if (ret)
		goto out_err;

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	if (!is_new_memtype_allowed(start, size, req_type, new_type))
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		goto out_free;

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	if (kernel_map_sync_memtype(start, size, new_type) < 0)
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		goto out_free;

	*type = new_type;
	return 0;

out_free:
	free_memtype(start, end);
	ret = -EBUSY;
out_err:
	return ret;
}

/**
 * io_free_memtype - Release a memory type mapping for a region of memory
 * @start: start (physical address) of the region
 * @end: end (physical address) of the region
 */
void io_free_memtype(resource_size_t start, resource_size_t end)
{
	free_memtype(start, end);
}

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pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
				unsigned long size, pgprot_t vma_prot)
{
	return vma_prot;
}

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#ifdef CONFIG_STRICT_DEVMEM
/* This check is done in drivers/char/mem.c in case of STRICT_DEVMEM*/
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static inline int range_is_allowed(unsigned long pfn, unsigned long size)
{
	return 1;
}
#else
675
/* This check is needed to avoid cache aliasing when PAT is enabled */
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static inline int range_is_allowed(unsigned long pfn, unsigned long size)
{
	u64 from = ((u64)pfn) << PAGE_SHIFT;
	u64 to = from + size;
	u64 cursor = from;

682 683 684
	if (!pat_enabled)
		return 1;

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	while (cursor < to) {
		if (!devmem_is_allowed(pfn)) {
			printk(KERN_INFO
		"Program %s tried to access /dev/mem between %Lx->%Lx.\n",
				current->comm, from, to);
			return 0;
		}
		cursor += PAGE_SIZE;
		pfn++;
	}
	return 1;
}
697
#endif /* CONFIG_STRICT_DEVMEM */
698

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int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
				unsigned long size, pgprot_t *vma_prot)
{
702
	unsigned long flags = _PAGE_CACHE_WB;
703

704 705 706
	if (!range_is_allowed(pfn, size))
		return 0;

707
	if (file->f_flags & O_SYNC) {
708
		flags = _PAGE_CACHE_UC_MINUS;
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	}

#ifdef CONFIG_X86_32
	/*
	 * On the PPro and successors, the MTRRs are used to set
	 * memory types for physical addresses outside main memory,
	 * so blindly setting UC or PWT on those pages is wrong.
	 * For Pentiums and earlier, the surround logic should disable
	 * caching for the high addresses through the KEN pin, but
	 * we maintain the tradition of paranoia in this code.
	 */
720
	if (!pat_enabled &&
721 722 723 724 725
	    !(boot_cpu_has(X86_FEATURE_MTRR) ||
	      boot_cpu_has(X86_FEATURE_K6_MTRR) ||
	      boot_cpu_has(X86_FEATURE_CYRIX_ARR) ||
	      boot_cpu_has(X86_FEATURE_CENTAUR_MCR)) &&
	    (pfn << PAGE_SHIFT) >= __pa(high_memory)) {
726
		flags = _PAGE_CACHE_UC;
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	}
#endif

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	*vma_prot = __pgprot((pgprot_val(*vma_prot) & ~_PAGE_CACHE_MASK) |
			     flags);
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	return 1;
}
734

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/*
 * Change the memory type for the physial address range in kernel identity
 * mapping space if that range is a part of identity map.
 */
int kernel_map_sync_memtype(u64 base, unsigned long size, unsigned long flags)
{
	unsigned long id_sz;

743
	if (base >= __pa(high_memory))
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		return 0;

	id_sz = (__pa(high_memory) < base + size) ?
				__pa(high_memory) - base :
				size;

	if (ioremap_change_attr((unsigned long)__va(base), id_sz, flags) < 0) {
		printk(KERN_INFO
			"%s:%d ioremap_change_attr failed %s "
			"for %Lx-%Lx\n",
			current->comm, current->pid,
			cattr_name(flags),
			base, (unsigned long long)(base + size));
		return -EINVAL;
	}
	return 0;
}

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/*
 * Internal interface to reserve a range of physical memory with prot.
 * Reserved non RAM regions only and after successful reserve_memtype,
 * this func also keeps identity mapping (if any) in sync with this new prot.
 */
767 768
static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
				int strict_prot)
769 770
{
	int is_ram = 0;
771
	int ret;
772
	unsigned long want_flags = (pgprot_val(*vma_prot) & _PAGE_CACHE_MASK);
773
	unsigned long flags = want_flags;
774

775
	is_ram = pat_pagerange_is_ram(paddr, paddr + size);
776

777
	/*
778 779 780
	 * reserve_pfn_range() for RAM pages. We do not refcount to keep
	 * track of number of mappings of RAM pages. We can assert that
	 * the type requested matches the type of first page in the range.
781
	 */
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	if (is_ram) {
		if (!pat_enabled)
			return 0;

		flags = lookup_memtype(paddr);
		if (want_flags != flags) {
			printk(KERN_WARNING
			"%s:%d map pfn RAM range req %s for %Lx-%Lx, got %s\n",
				current->comm, current->pid,
				cattr_name(want_flags),
				(unsigned long long)paddr,
				(unsigned long long)(paddr + size),
				cattr_name(flags));
			*vma_prot = __pgprot((pgprot_val(*vma_prot) &
					      (~_PAGE_CACHE_MASK)) |
					     flags);
		}
799
		return 0;
800
	}
801 802 803 804 805 806

	ret = reserve_memtype(paddr, paddr + size, want_flags, &flags);
	if (ret)
		return ret;

	if (flags != want_flags) {
807 808
		if (strict_prot ||
		    !is_new_memtype_allowed(paddr, size, want_flags, flags)) {
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			free_memtype(paddr, paddr + size);
			printk(KERN_ERR "%s:%d map pfn expected mapping type %s"
				" for %Lx-%Lx, got %s\n",
				current->comm, current->pid,
				cattr_name(want_flags),
				(unsigned long long)paddr,
				(unsigned long long)(paddr + size),
				cattr_name(flags));
			return -EINVAL;
		}
		/*
		 * We allow returning different type than the one requested in
		 * non strict case.
		 */
		*vma_prot = __pgprot((pgprot_val(*vma_prot) &
				      (~_PAGE_CACHE_MASK)) |
				     flags);
826 827
	}

828
	if (kernel_map_sync_memtype(paddr, size, flags) < 0) {
829 830 831 832 833 834 835 836 837 838 839 840 841 842
		free_memtype(paddr, paddr + size);
		return -EINVAL;
	}
	return 0;
}

/*
 * Internal interface to free a range of physical memory.
 * Frees non RAM regions only.
 */
static void free_pfn_range(u64 paddr, unsigned long size)
{
	int is_ram;

843
	is_ram = pat_pagerange_is_ram(paddr, paddr + size);
844 845 846 847 848 849 850 851 852 853 854 855 856
	if (is_ram == 0)
		free_memtype(paddr, paddr + size);
}

/*
 * track_pfn_vma_copy is called when vma that is covering the pfnmap gets
 * copied through copy_page_range().
 *
 * If the vma has a linear pfn mapping for the entire range, we get the prot
 * from pte and reserve the entire vma range with single reserve_pfn_range call.
 */
int track_pfn_vma_copy(struct vm_area_struct *vma)
{
857
	resource_size_t paddr;
858
	unsigned long prot;
859
	unsigned long vma_size = vma->vm_end - vma->vm_start;
860
	pgprot_t pgprot;
861 862 863

	if (is_linear_pfn_mapping(vma)) {
		/*
864 865
		 * reserve the whole chunk covered by vma. We need the
		 * starting address and protection from pte.
866
		 */
867
		if (follow_phys(vma, vma->vm_start, 0, &prot, &paddr)) {
868
			WARN_ON_ONCE(1);
869
			return -EINVAL;
870
		}
871 872
		pgprot = __pgprot(prot);
		return reserve_pfn_range(paddr, vma_size, &pgprot, 1);
873 874 875 876 877 878 879 880 881 882 883 884 885
	}

	return 0;
}

/*
 * track_pfn_vma_new is called when a _new_ pfn mapping is being established
 * for physical range indicated by pfn and size.
 *
 * prot is passed in as a parameter for the new mapping. If the vma has a
 * linear pfn mapping for the entire range reserve the entire vma range with
 * single reserve_pfn_range call.
 */
886
int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t *prot,
887 888
			unsigned long pfn, unsigned long size)
{
889
	unsigned long flags;
890
	resource_size_t paddr;
891
	unsigned long vma_size = vma->vm_end - vma->vm_start;
892 893 894

	if (is_linear_pfn_mapping(vma)) {
		/* reserve the whole chunk starting from vm_pgoff */
895
		paddr = (resource_size_t)vma->vm_pgoff << PAGE_SHIFT;
896
		return reserve_pfn_range(paddr, vma_size, prot, 0);
897 898
	}

899 900 901 902 903 904 905 906
	if (!pat_enabled)
		return 0;

	/* for vm_insert_pfn and friends, we set prot based on lookup */
	flags = lookup_memtype(pfn << PAGE_SHIFT);
	*prot = __pgprot((pgprot_val(vma->vm_page_prot) & (~_PAGE_CACHE_MASK)) |
			 flags);

907 908 909 910 911 912 913 914 915 916 917
	return 0;
}

/*
 * untrack_pfn_vma is called while unmapping a pfnmap for a region.
 * untrack can be called for a specific region indicated by pfn and size or
 * can be for the entire vma (in which case size can be zero).
 */
void untrack_pfn_vma(struct vm_area_struct *vma, unsigned long pfn,
			unsigned long size)
{
918
	resource_size_t paddr;
919
	unsigned long vma_size = vma->vm_end - vma->vm_start;
920 921 922

	if (is_linear_pfn_mapping(vma)) {
		/* free the whole chunk starting from vm_pgoff */
923
		paddr = (resource_size_t)vma->vm_pgoff << PAGE_SHIFT;
924 925 926 927 928
		free_pfn_range(paddr, vma_size);
		return;
	}
}

929 930 931 932 933 934 935
pgprot_t pgprot_writecombine(pgprot_t prot)
{
	if (pat_enabled)
		return __pgprot(pgprot_val(prot) | _PAGE_CACHE_WC);
	else
		return pgprot_noncached(prot);
}
936
EXPORT_SYMBOL_GPL(pgprot_writecombine);
937

938
#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_PAT)
939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960

/* get Nth element of the linked list */
static struct memtype *memtype_get_idx(loff_t pos)
{
	struct memtype *list_node, *print_entry;
	int i = 1;

	print_entry  = kmalloc(sizeof(struct memtype), GFP_KERNEL);
	if (!print_entry)
		return NULL;

	spin_lock(&memtype_lock);
	list_for_each_entry(list_node, &memtype_list, nd) {
		if (pos == i) {
			*print_entry = *list_node;
			spin_unlock(&memtype_lock);
			return print_entry;
		}
		++i;
	}
	spin_unlock(&memtype_lock);
	kfree(print_entry);
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Ingo Molnar 已提交
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962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991
	return NULL;
}

static void *memtype_seq_start(struct seq_file *seq, loff_t *pos)
{
	if (*pos == 0) {
		++*pos;
		seq_printf(seq, "PAT memtype list:\n");
	}

	return memtype_get_idx(*pos);
}

static void *memtype_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	++*pos;
	return memtype_get_idx(*pos);
}

static void memtype_seq_stop(struct seq_file *seq, void *v)
{
}

static int memtype_seq_show(struct seq_file *seq, void *v)
{
	struct memtype *print_entry = (struct memtype *)v;

	seq_printf(seq, "%s @ 0x%Lx-0x%Lx\n", cattr_name(print_entry->type),
			print_entry->start, print_entry->end);
	kfree(print_entry);
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Ingo Molnar 已提交
992

993 994 995
	return 0;
}

T
Tobias Klauser 已提交
996
static const struct seq_operations memtype_seq_ops = {
997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016
	.start = memtype_seq_start,
	.next  = memtype_seq_next,
	.stop  = memtype_seq_stop,
	.show  = memtype_seq_show,
};

static int memtype_seq_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &memtype_seq_ops);
}

static const struct file_operations memtype_fops = {
	.open    = memtype_seq_open,
	.read    = seq_read,
	.llseek  = seq_lseek,
	.release = seq_release,
};

static int __init pat_memtype_list_init(void)
{
1017 1018 1019 1020
	if (pat_enabled) {
		debugfs_create_file("pat_memtype_list", S_IRUSR,
				    arch_debugfs_dir, NULL, &memtype_fops);
	}
1021 1022 1023 1024 1025
	return 0;
}

late_initcall(pat_memtype_list_init);

1026
#endif /* CONFIG_DEBUG_FS && CONFIG_X86_PAT */