[mirror_ubuntu-artful-kernel.git] / arch / mips / mm / highmem.c

#include <linux/compiler.h>
#include <linux/module.h>
#include <linux/highmem.h>
#include <linux/sched.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)
{
	unsigned long vaddr;
	int idx, type;

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

	type = kmap_atomic_idx_push();
	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)
{
	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
	int type __maybe_unused;

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

	type = kmap_atomic_idx();
#ifdef CONFIG_DEBUG_HIGHMEM
	{
		int idx = type + KM_TYPE_NR * smp_processor_id();

		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
	kmap_atomic_idx_pop();
	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)
{
	unsigned long vaddr;
	int idx, type;

	pagefault_disable();

	type = kmap_atomic_idx_push();
	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
	1	#include <linux/compiler.h>
	2	#include <linux/module.h>
	3	#include <linux/highmem.h>
	4	#include <linux/sched.h>
	5	#include <linux/smp.h>
	6	#include <asm/fixmap.h>
	7	#include <asm/tlbflush.h>
	8
	9	static pte_t *kmap_pte;
	10
	11	unsigned long highstart_pfn, highend_pfn;
	12
	13	void kmap(struct page page)
	14	{
	15	void *addr;
	16
	17	might_sleep();
	18	if (!PageHighMem(page))
	19	return page_address(page);
	20	addr = kmap_high(page);
	21	flush_tlb_one((unsigned long)addr);
	22
	23	return addr;
	24	}
	25	EXPORT_SYMBOL(kmap);
	26
	27	void kunmap(struct page *page)
	28	{
	29	BUG_ON(in_interrupt());
	30	if (!PageHighMem(page))
	31	return;
	32	kunmap_high(page);
	33	}
	34	EXPORT_SYMBOL(kunmap);
	35
	36	/*
	37	* kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
	38	* no global lock is needed and because the kmap code must perform a global TLB
	39	* invalidation when the kmap pool wraps.
	40	*
	41	* However when holding an atomic kmap is is not legal to sleep, so atomic
	42	* kmaps are appropriate for short, tight code paths only.
	43	*/
	44
	45	void kmap_atomic(struct page page)
	46	{
	47	unsigned long vaddr;
	48	int idx, type;
	49
	50	/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
	51	pagefault_disable();
	52	if (!PageHighMem(page))
	53	return page_address(page);
	54
	55	type = kmap_atomic_idx_push();
	56	idx = type + KM_TYPE_NR*smp_processor_id();
	57	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
	58	#ifdef CONFIG_DEBUG_HIGHMEM
	59	BUG_ON(!pte_none(*(kmap_pte - idx)));
	60	#endif
	61	set_pte(kmap_pte-idx, mk_pte(page, PAGE_KERNEL));
	62	local_flush_tlb_one((unsigned long)vaddr);
	63
	64	return (void*) vaddr;
	65	}
	66	EXPORT_SYMBOL(kmap_atomic);
	67
	68	void __kunmap_atomic(void *kvaddr)
	69	{
	70	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
	71	int type __maybe_unused;
	72
	73	if (vaddr < FIXADDR_START) { // FIXME
	74	pagefault_enable();
	75	return;
	76	}
	77
	78	type = kmap_atomic_idx();
	79	#ifdef CONFIG_DEBUG_HIGHMEM
	80	{
	81	int idx = type + KM_TYPE_NR * smp_processor_id();
	82
	83	BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
	84
	85	/*
	86	* force other mappings to Oops if they'll try to access
	87	* this pte without first remap it
	88	*/
	89	pte_clear(&init_mm, vaddr, kmap_pte-idx);
	90	local_flush_tlb_one(vaddr);
	91	}
	92	#endif
	93	kmap_atomic_idx_pop();
	94	pagefault_enable();
	95	}
	96	EXPORT_SYMBOL(__kunmap_atomic);
	97
	98	/*
	99	* This is the same as kmap_atomic() but can map memory that doesn't
	100	* have a struct page associated with it.
	101	*/
	102	void *kmap_atomic_pfn(unsigned long pfn)
	103	{
	104	unsigned long vaddr;
	105	int idx, type;
	106
	107	pagefault_disable();
	108
	109	type = kmap_atomic_idx_push();
	110	idx = type + KM_TYPE_NR*smp_processor_id();
	111	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
	112	set_pte(kmap_pte-idx, pfn_pte(pfn, PAGE_KERNEL));
	113	flush_tlb_one(vaddr);
	114
	115	return (void*) vaddr;
	116	}
	117
	118	struct page kmap_atomic_to_page(void ptr)
	119	{
	120	unsigned long idx, vaddr = (unsigned long)ptr;
	121	pte_t *pte;
	122
	123	if (vaddr < FIXADDR_START)
	124	return virt_to_page(ptr);
	125
	126	idx = virt_to_fix(vaddr);
	127	pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
	128	return pte_page(*pte);
	129	}
	130
	131	void __init kmap_init(void)
	132	{
	133	unsigned long kmap_vstart;
	134
	135	/* cache the first kmap pte */
	136	kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
	137	kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
	138	}