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

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

void *__kmap(struct page *page)
{
	void *addr;

	might_sleep();
	if (!PageHighMem(page))
		return page_address(page);
	addr = kmap_high(page);
	flush_tlb_one((unsigned long)addr);

	return addr;
}

void __kunmap(struct page *page)
{
	BUG_ON(in_interrupt());
	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(struct page *page, enum km_type type)
{
	enum fixed_addresses idx;
	unsigned long vaddr;

	/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
	pagefault_disable();
	if (!PageHighMem(page))
		return page_address(page);

	debug_kmap_atomic(type);
	idx = type + KM_TYPE_NR*smp_processor_id();
	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
#ifdef CONFIG_DEBUG_HIGHMEM
	BUG_ON(!pte_none(*(kmap_pte - idx)));
#endif
	set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
	local_flush_tlb_one((unsigned long)vaddr);

	return (void*) vaddr;
}

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

	if (vaddr < FIXADDR_START) { // FIXME
		pagefault_enable();
		return;
	}

	BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));

	/*
	 * force other mappings to Oops if they'll try to access
	 * this pte without first remap it
	 */
	pte_clear(&init_mm, vaddr, kmap_pte-idx);
	local_flush_tlb_one(vaddr);
#endif

	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();

	debug_kmap_atomic(type);
	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));
	flush_tlb_one(vaddr);

	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);
Commit	Line	Data
1da177e4 LT	1	#include <linux/module.h>
	2	#include <linux/highmem.h>
	3	#include <asm/tlbflush.h>
	4
	5	void __kmap(struct page page)
	6	{
	7	void *addr;
	8
	9	might_sleep();
	10	if (!PageHighMem(page))
	11	return page_address(page);
	12	addr = kmap_high(page);
	13	flush_tlb_one((unsigned long)addr);
	14
	15	return addr;
	16	}
	17
	18	void __kunmap(struct page *page)
	19	{
b72b7092	20	BUG_ON(in_interrupt());
1da177e4 LT	21	if (!PageHighMem(page))
	22	return;
	23	kunmap_high(page);
	24	}
	25
	26	/*
	27	* kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
	28	* no global lock is needed and because the kmap code must perform a global TLB
	29	* invalidation when the kmap pool wraps.
	30	*
	31	* However when holding an atomic kmap is is not legal to sleep, so atomic
	32	* kmaps are appropriate for short, tight code paths only.
	33	*/
	34
	35	void __kmap_atomic(struct page page, enum km_type type)
	36	{
	37	enum fixed_addresses idx;
	38	unsigned long vaddr;
	39
	40	/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
a866374a	41	pagefault_disable();
1da177e4 LT	42	if (!PageHighMem(page))
	43	return page_address(page);
	44
7ca43e75	45	debug_kmap_atomic(type);
1da177e4 LT	46	idx = type + KM_TYPE_NR*smp_processor_id();
	47	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
	48	#ifdef CONFIG_DEBUG_HIGHMEM
b72b7092	49	BUG_ON(!pte_none(*(kmap_pte - idx)));
1da177e4 LT	50	#endif
	51	set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
	52	local_flush_tlb_one((unsigned long)vaddr);
	53
	54	return (void*) vaddr;
	55	}
	56
	57	void __kunmap_atomic(void *kvaddr, enum km_type type)
	58	{
	59	#ifdef CONFIG_DEBUG_HIGHMEM
	60	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
	61	enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id();
	62
	63	if (vaddr < FIXADDR_START) { // FIXME
a866374a	64	pagefault_enable();
1da177e4 LT	65	return;
	66	}
	67
b72b7092	68	BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
1da177e4 LT	69
	70	/*
	71	* force other mappings to Oops if they'll try to access
	72	* this pte without first remap it
	73	*/
	74	pte_clear(&init_mm, vaddr, kmap_pte-idx);
	75	local_flush_tlb_one(vaddr);
	76	#endif
	77
a866374a	78	pagefault_enable();
1da177e4 LT	79	}
1da177e4 LT	80
60080265 RB	81	/*
	82	* This is the same as kmap_atomic() but can map memory that doesn't
	83	* have a struct page associated with it.
	84	*/
	85	void *kmap_atomic_pfn(unsigned long pfn, enum km_type type)
	86	{
	87	enum fixed_addresses idx;
	88	unsigned long vaddr;
	89
a866374a	90	pagefault_disable();
60080265	91
7ca43e75	92	debug_kmap_atomic(type);
60080265 RB	93	idx = type + KM_TYPE_NR*smp_processor_id();
	94	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
	95	set_pte(kmap_pte-idx, pfn_pte(pfn, kmap_prot));
	96	flush_tlb_one(vaddr);
	97
	98	return (void*) vaddr;
	99	}
	100
1da177e4 LT	101	struct page __kmap_atomic_to_page(void ptr)
	102	{
	103	unsigned long idx, vaddr = (unsigned long)ptr;
	104	pte_t *pte;
	105
	106	if (vaddr < FIXADDR_START)
	107	return virt_to_page(ptr);
	108
	109	idx = virt_to_fix(vaddr);
	110	pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
	111	return pte_page(*pte);
	112	}
	113
	114	EXPORT_SYMBOL(__kmap);
	115	EXPORT_SYMBOL(__kunmap);
	116	EXPORT_SYMBOL(__kmap_atomic);
	117	EXPORT_SYMBOL(__kunmap_atomic);