[deliverable/linux.git] / arch / i386 / mm / highmem.c

#include <linux/highmem.h>
#include <linux/module.h>

void *kmap(struct page *page)
{
	might_sleep();
	if (!PageHighMem(page))
		return page_address(page);
	return kmap_high(page);
}

void kunmap(struct page *page)
{
	if (in_interrupt())
		BUG();
	if (!PageHighMem(page))
		return;
	kunmap_high(page);
}

/*
 * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
 * no global lock is needed and because the kmap code must perform a global TLB
 * invalidation when the kmap pool wraps.
 *
 * However when holding an atomic kmap is is not legal to sleep, so atomic
 * kmaps are appropriate for short, tight code paths only.
 */
void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot)
{
	enum fixed_addresses idx;
	unsigned long vaddr;

	/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
	pagefault_disable();

	idx = type + KM_TYPE_NR*smp_processor_id();
	BUG_ON(!pte_none(*(kmap_pte-idx)));

	if (!PageHighMem(page))
		return page_address(page);

	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
	set_pte(kmap_pte-idx, mk_pte(page, prot));
	arch_flush_lazy_mmu_mode();

	return (void*) vaddr;
}

void *kmap_atomic(struct page *page, enum km_type type)
{
	return kmap_atomic_prot(page, type, kmap_prot);
}

void kunmap_atomic(void *kvaddr, enum km_type type)
{
	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
	enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id();

	/*
	 * Force other mappings to Oops if they'll try to access this pte
	 * without first remap it.  Keeping stale mappings around is a bad idea
	 * also, in case the page changes cacheability attributes or becomes
	 * a protected page in a hypervisor.
	 */
	if (vaddr == __fix_to_virt(FIX_KMAP_BEGIN+idx))
		kpte_clear_flush(kmap_pte-idx, vaddr);
	else {
#ifdef CONFIG_DEBUG_HIGHMEM
		BUG_ON(vaddr < PAGE_OFFSET);
		BUG_ON(vaddr >= (unsigned long)high_memory);
#endif
	}

	arch_flush_lazy_mmu_mode();
	pagefault_enable();
}

/* This is the same as kmap_atomic() but can map memory that doesn't
 * have a struct page associated with it.
 */
void *kmap_atomic_pfn(unsigned long pfn, enum km_type type)
{
	enum fixed_addresses idx;
	unsigned long vaddr;

	pagefault_disable();

	idx = type + KM_TYPE_NR*smp_processor_id();
	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
	set_pte(kmap_pte-idx, pfn_pte(pfn, kmap_prot));
	arch_flush_lazy_mmu_mode();

	return (void*) vaddr;
}

struct page *kmap_atomic_to_page(void *ptr)
{
	unsigned long idx, vaddr = (unsigned long)ptr;
	pte_t *pte;

	if (vaddr < FIXADDR_START)
		return virt_to_page(ptr);

	idx = virt_to_fix(vaddr);
	pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
	return pte_page(*pte);
}

EXPORT_SYMBOL(kmap);
EXPORT_SYMBOL(kunmap);
EXPORT_SYMBOL(kmap_atomic);
EXPORT_SYMBOL(kunmap_atomic);
EXPORT_SYMBOL(kmap_atomic_to_page);
Commit	Line	Data
1da177e4	1	#include <linux/highmem.h>
129f6946	2	#include <linux/module.h>
1da177e4 LT	3
	4	void kmap(struct page page)
	5	{
	6	might_sleep();
	7	if (!PageHighMem(page))
	8	return page_address(page);
	9	return kmap_high(page);
	10	}
	11
	12	void kunmap(struct page *page)
	13	{
	14	if (in_interrupt())
	15	BUG();
	16	if (!PageHighMem(page))
	17	return;
	18	kunmap_high(page);
	19	}
	20
	21	/*
	22	* kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
	23	* no global lock is needed and because the kmap code must perform a global TLB
	24	* invalidation when the kmap pool wraps.
	25	*
	26	* However when holding an atomic kmap is is not legal to sleep, so atomic
	27	* kmaps are appropriate for short, tight code paths only.
	28	*/
ce6234b5	29	void kmap_atomic_prot(struct page page, enum km_type type, pgprot_t prot)
1da177e4 LT	30	{
	31	enum fixed_addresses idx;
	32	unsigned long vaddr;
	33
	34	/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
a866374a	35	pagefault_disable();
656dad31 IM	36
	37	idx = type + KM_TYPE_NR*smp_processor_id();
	38	BUG_ON(!pte_none(*(kmap_pte-idx)));
	39
1da177e4 LT	40	if (!PageHighMem(page))
	41	return page_address(page);
	42
1da177e4	43	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
ce6234b5	44	set_pte(kmap_pte-idx, mk_pte(page, prot));
49f19710	45	arch_flush_lazy_mmu_mode();
1da177e4 LT	46
	47	return (void*) vaddr;
	48	}
	49
ce6234b5 JF	50	void kmap_atomic(struct page page, enum km_type type)
	51	{
	52	return kmap_atomic_prot(page, type, kmap_prot);
	53	}
	54
1da177e4 LT	55	void kunmap_atomic(void *kvaddr, enum km_type type)
1da177e4 LT	56	{
1da177e4 LT	57	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
	58	enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id();
	59
1da177e4	60	/*
23002d88 ZA	61	* Force other mappings to Oops if they'll try to access this pte
	62	* without first remap it. Keeping stale mappings around is a bad idea
	63	* also, in case the page changes cacheability attributes or becomes
	64	* a protected page in a hypervisor.
1da177e4	65	*/
3b17979b JF	66	if (vaddr == __fix_to_virt(FIX_KMAP_BEGIN+idx))
	67	kpte_clear_flush(kmap_pte-idx, vaddr);
	68	else {
	69	#ifdef CONFIG_DEBUG_HIGHMEM
	70	BUG_ON(vaddr < PAGE_OFFSET);
	71	BUG_ON(vaddr >= (unsigned long)high_memory);
	72	#endif
	73	}
1da177e4	74
7b2f27f4	75	arch_flush_lazy_mmu_mode();
a866374a	76	pagefault_enable();
1da177e4 LT	77	}
1da177e4 LT	78
60e64d46 VG	79	/* This is the same as kmap_atomic() but can map memory that doesn't
	80	* have a struct page associated with it.
	81	*/
	82	void *kmap_atomic_pfn(unsigned long pfn, enum km_type type)
	83	{
	84	enum fixed_addresses idx;
	85	unsigned long vaddr;
	86
a866374a	87	pagefault_disable();
60e64d46 VG	88
	89	idx = type + KM_TYPE_NR*smp_processor_id();
	90	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
	91	set_pte(kmap_pte-idx, pfn_pte(pfn, kmap_prot));
49f19710	92	arch_flush_lazy_mmu_mode();
60e64d46 VG	93
	94	return (void*) vaddr;
	95	}
	96
1da177e4 LT	97	struct page kmap_atomic_to_page(void ptr)
	98	{
	99	unsigned long idx, vaddr = (unsigned long)ptr;
	100	pte_t *pte;
	101
	102	if (vaddr < FIXADDR_START)
	103	return virt_to_page(ptr);
	104
	105	idx = virt_to_fix(vaddr);
	106	pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
	107	return pte_page(*pte);
	108	}
	109
129f6946 AD	110	EXPORT_SYMBOL(kmap);
	111	EXPORT_SYMBOL(kunmap);
	112	EXPORT_SYMBOL(kmap_atomic);
	113	EXPORT_SYMBOL(kunmap_atomic);
	114	EXPORT_SYMBOL(kmap_atomic_to_page);