[net-next-2.6.git] / arch / sparc / mm / highmem.c

/*
 *  highmem.c: virtual kernel memory mappings for high memory
 *
 *  Provides kernel-static versions of atomic kmap functions originally
 *  found as inlines in include/asm-sparc/highmem.h.  These became
 *  needed as kmap_atomic() and kunmap_atomic() started getting
 *  called from within modules.
 *  -- Tomas Szepe <szepe@pinerecords.com>, September 2002
 *
 *  But kmap_atomic() and kunmap_atomic() cannot be inlined in
 *  modules because they are loaded with btfixup-ped functions.
 */

/*
 * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
 * gives a more generic (and caching) interface. But kmap_atomic can
 * be used in IRQ contexts, so in some (very limited) cases we need it.
 *
 * XXX This is an old text. Actually, it's good to use atomic kmaps,
 * provided you remember that they are atomic and not try to sleep
 * with a kmap taken, much like a spinlock. Non-atomic kmaps are
 * shared by CPUs, and so precious, and establishing them requires IPI.
 * Atomic kmaps are lightweight and we may have NCPUS more of them.
 */
#include <linux/mm.h>
#include <linux/highmem.h>
#include <asm/pgalloc.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/fixmap.h>

void *kmap_atomic(struct page *page, enum km_type type)
{
	unsigned long 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);

/* XXX Fix - Anton */
#if 0
	__flush_cache_one(vaddr);
#else
	flush_cache_all();
#endif

#ifdef CONFIG_DEBUG_HIGHMEM
	BUG_ON(!pte_none(*(kmap_pte-idx)));
#endif
	set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
/* XXX Fix - Anton */
#if 0
	__flush_tlb_one(vaddr);
#else
	flush_tlb_all();
#endif

	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;
	unsigned long 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));

/* XXX Fix - Anton */
#if 0
	__flush_cache_one(vaddr);
#else
	flush_cache_all();
#endif

	/*
	 * 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);
/* XXX Fix - Anton */
#if 0
	__flush_tlb_one(vaddr);
#else
	flush_tlb_all();
#endif
#endif

	pagefault_enable();
}
EXPORT_SYMBOL(kunmap_atomic);

/* We may be fed a pagetable here by ptep_to_xxx and others. */
struct page *kmap_atomic_to_page(void *ptr)
{
	unsigned long idx, vaddr = (unsigned long)ptr;
	pte_t *pte;

	if (vaddr < SRMMU_NOCACHE_VADDR)
		return virt_to_page(ptr);
	if (vaddr < PKMAP_BASE)
		return pfn_to_page(__nocache_pa(vaddr) >> PAGE_SHIFT);
	BUG_ON(vaddr < FIXADDR_START);
	BUG_ON(vaddr > FIXADDR_TOP);

	idx = virt_to_fix(vaddr);
	pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
	return pte_page(*pte);
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* highmem.c: virtual kernel memory mappings for high memory
	3	*
	4	* Provides kernel-static versions of atomic kmap functions originally
	5	* found as inlines in include/asm-sparc/highmem.h. These became
	6	* needed as kmap_atomic() and kunmap_atomic() started getting
	7	* called from within modules.
	8	* -- Tomas Szepe <szepe@pinerecords.com>, September 2002
	9	*
	10	* But kmap_atomic() and kunmap_atomic() cannot be inlined in
	11	* modules because they are loaded with btfixup-ped functions.
	12	*/
	13
	14	/*
	15	* The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
	16	* gives a more generic (and caching) interface. But kmap_atomic can
	17	* be used in IRQ contexts, so in some (very limited) cases we need it.
	18	*
	19	* XXX This is an old text. Actually, it's good to use atomic kmaps,
	20	* provided you remember that they are atomic and not try to sleep
	21	* with a kmap taken, much like a spinlock. Non-atomic kmaps are
	22	* shared by CPUs, and so precious, and establishing them requires IPI.
	23	* Atomic kmaps are lightweight and we may have NCPUS more of them.
	24	*/
	25	#include <linux/mm.h>
	26	#include <linux/highmem.h>
	27	#include <asm/pgalloc.h>
	28	#include <asm/cacheflush.h>
	29	#include <asm/tlbflush.h>
	30	#include <asm/fixmap.h>
	31
	32	void kmap_atomic(struct page page, enum km_type type)
	33	{
	34	unsigned long idx;
	35	unsigned long vaddr;
	36
	37	/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
a866374a	38	pagefault_disable();
1da177e4 LT	39	if (!PageHighMem(page))
	40	return page_address(page);
	41
7ca43e75	42	debug_kmap_atomic(type);
1da177e4 LT	43	idx = type + KM_TYPE_NR*smp_processor_id();
	44	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
	45
	46	/* XXX Fix - Anton */
	47	#if 0
	48	__flush_cache_one(vaddr);
	49	#else
	50	flush_cache_all();
	51	#endif
	52
	53	#ifdef CONFIG_DEBUG_HIGHMEM
	54	BUG_ON(!pte_none(*(kmap_pte-idx)));
	55	#endif
	56	set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
	57	/* XXX Fix - Anton */
	58	#if 0
	59	__flush_tlb_one(vaddr);
	60	#else
	61	flush_tlb_all();
	62	#endif
	63
	64	return (void*) vaddr;
	65	}
6943f3da	66	EXPORT_SYMBOL(kmap_atomic);
1da177e4 LT	67
	68	void kunmap_atomic(void *kvaddr, enum km_type type)
	69	{
	70	#ifdef CONFIG_DEBUG_HIGHMEM
	71	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
	72	unsigned long idx = type + KM_TYPE_NR*smp_processor_id();
	73
	74	if (vaddr < FIXADDR_START) { // FIXME
a866374a	75	pagefault_enable();
1da177e4 LT	76	return;
	77	}
	78
	79	BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN+idx));
	80
	81	/* XXX Fix - Anton */
	82	#if 0
	83	__flush_cache_one(vaddr);
	84	#else
	85	flush_cache_all();
	86	#endif
	87
	88	/*
	89	* force other mappings to Oops if they'll try to access
	90	* this pte without first remap it
	91	*/
	92	pte_clear(&init_mm, vaddr, kmap_pte-idx);
	93	/* XXX Fix - Anton */
	94	#if 0
	95	__flush_tlb_one(vaddr);
	96	#else
	97	flush_tlb_all();
	98	#endif
	99	#endif
	100
a866374a	101	pagefault_enable();
1da177e4	102	}
6943f3da	103	EXPORT_SYMBOL(kunmap_atomic);
1da177e4 LT	104
	105	/* We may be fed a pagetable here by ptep_to_xxx and others. */
	106	struct page kmap_atomic_to_page(void ptr)
	107	{
	108	unsigned long idx, vaddr = (unsigned long)ptr;
	109	pte_t *pte;
	110
	111	if (vaddr < SRMMU_NOCACHE_VADDR)
	112	return virt_to_page(ptr);
	113	if (vaddr < PKMAP_BASE)
	114	return pfn_to_page(__nocache_pa(vaddr) >> PAGE_SHIFT);
	115	BUG_ON(vaddr < FIXADDR_START);
	116	BUG_ON(vaddr > FIXADDR_TOP);
	117
	118	idx = virt_to_fix(vaddr);
	119	pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
	120	return pte_page(*pte);
	121	}