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

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

static pte_t *kmap_pte;

unsigned long highstart_pfn, highend_pfn;

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;
}
EXPORT_SYMBOL(__kmap);

void __kunmap(struct page *page)
{
	BUG_ON(in_interrupt());
	if (!PageHighMem(page))
		return;
	kunmap_high(page);
}
EXPORT_SYMBOL(__kunmap);

/*
 * 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, PAGE_KERNEL));
	local_flush_tlb_one((unsigned long)vaddr);

	return (void*) vaddr;
}
EXPORT_SYMBOL(__kmap_atomic);

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();
}
EXPORT_SYMBOL(__kunmap_atomic);

/*
 * 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, PAGE_KERNEL));
	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);
}

void __init kmap_init(void)
{
	unsigned long kmap_vstart;

	/* cache the first kmap pte */
	kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
	kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
}
Commit	Line	Data
1da177e4 LT	1	#include <linux/module.h>
1da177e4 LT	2	#include <linux/highmem.h>
631330f5	3	#include <linux/smp.h>
bb86bf28	4	#include <asm/fixmap.h>
1da177e4 LT	5	#include <asm/tlbflush.h>
1da177e4 LT	6
bb86bf28 RB	7	static pte_t *kmap_pte;
	8
	9	unsigned long highstart_pfn, highend_pfn;
	10
1da177e4 LT	11	void __kmap(struct page page)
	12	{
	13	void *addr;
	14
	15	might_sleep();
	16	if (!PageHighMem(page))
	17	return page_address(page);
	18	addr = kmap_high(page);
	19	flush_tlb_one((unsigned long)addr);
	20
	21	return addr;
	22	}
bb86bf28	23	EXPORT_SYMBOL(__kmap);
1da177e4 LT	24
	25	void __kunmap(struct page *page)
	26	{
b72b7092	27	BUG_ON(in_interrupt());
1da177e4 LT	28	if (!PageHighMem(page))
	29	return;
	30	kunmap_high(page);
	31	}
bb86bf28	32	EXPORT_SYMBOL(__kunmap);
1da177e4 LT	33
	34	/*
	35	* kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
	36	* no global lock is needed and because the kmap code must perform a global TLB
	37	* invalidation when the kmap pool wraps.
	38	*
	39	* However when holding an atomic kmap is is not legal to sleep, so atomic
	40	* kmaps are appropriate for short, tight code paths only.
	41	*/
	42
	43	void __kmap_atomic(struct page page, enum km_type type)
	44	{
	45	enum fixed_addresses idx;
	46	unsigned long vaddr;
	47
	48	/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
a866374a	49	pagefault_disable();
1da177e4 LT	50	if (!PageHighMem(page))
	51	return page_address(page);
	52
7ca43e75	53	debug_kmap_atomic(type);
1da177e4 LT	54	idx = type + KM_TYPE_NR*smp_processor_id();
	55	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
	56	#ifdef CONFIG_DEBUG_HIGHMEM
b72b7092	57	BUG_ON(!pte_none(*(kmap_pte - idx)));
1da177e4	58	#endif
bb86bf28	59	set_pte(kmap_pte-idx, mk_pte(page, PAGE_KERNEL));
1da177e4 LT	60	local_flush_tlb_one((unsigned long)vaddr);
	61
	62	return (void*) vaddr;
	63	}
bb86bf28	64	EXPORT_SYMBOL(__kmap_atomic);
1da177e4 LT	65
	66	void __kunmap_atomic(void *kvaddr, enum km_type type)
	67	{
	68	#ifdef CONFIG_DEBUG_HIGHMEM
	69	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
	70	enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id();
	71
	72	if (vaddr < FIXADDR_START) { // FIXME
a866374a	73	pagefault_enable();
1da177e4 LT	74	return;
	75	}
	76
b72b7092	77	BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
1da177e4 LT	78
	79	/*
	80	* force other mappings to Oops if they'll try to access
	81	* this pte without first remap it
	82	*/
	83	pte_clear(&init_mm, vaddr, kmap_pte-idx);
	84	local_flush_tlb_one(vaddr);
	85	#endif
	86
a866374a	87	pagefault_enable();
1da177e4	88	}
bb86bf28	89	EXPORT_SYMBOL(__kunmap_atomic);
1da177e4	90
60080265 RB	91	/*
	92	* This is the same as kmap_atomic() but can map memory that doesn't
	93	* have a struct page associated with it.
	94	*/
	95	void *kmap_atomic_pfn(unsigned long pfn, enum km_type type)
	96	{
	97	enum fixed_addresses idx;
	98	unsigned long vaddr;
	99
a866374a	100	pagefault_disable();
60080265	101
7ca43e75	102	debug_kmap_atomic(type);
60080265 RB	103	idx = type + KM_TYPE_NR*smp_processor_id();
60080265 RB	104	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
bb86bf28	105	set_pte(kmap_pte-idx, pfn_pte(pfn, PAGE_KERNEL));
60080265 RB	106	flush_tlb_one(vaddr);
	107
	108	return (void*) vaddr;
	109	}
	110
1da177e4 LT	111	struct page __kmap_atomic_to_page(void ptr)
	112	{
	113	unsigned long idx, vaddr = (unsigned long)ptr;
	114	pte_t *pte;
	115
	116	if (vaddr < FIXADDR_START)
	117	return virt_to_page(ptr);
	118
	119	idx = virt_to_fix(vaddr);
	120	pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
	121	return pte_page(*pte);
	122	}
	123
bb86bf28 RB	124	void __init kmap_init(void)
	125	{
	126	unsigned long kmap_vstart;
	127
	128	/* cache the first kmap pte */
	129	kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
	130	kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
	131	}