[linux-2.6-block.git] / arch / xtensa / mm / highmem.c

/*
 * High memory support for Xtensa architecture
 *
 * This file is subject to the terms and conditions of the GNU General
 * Public License.  See the file "COPYING" in the main directory of
 * this archive for more details.
 *
 * Copyright (C) 2014 Cadence Design Systems Inc.
 */

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

static pte_t *kmap_pte;

#if DCACHE_WAY_SIZE > PAGE_SIZE
unsigned int last_pkmap_nr_arr[DCACHE_N_COLORS];
wait_queue_head_t pkmap_map_wait_arr[DCACHE_N_COLORS];

static void __init kmap_waitqueues_init(void)
{
	unsigned int i;

	for (i = 0; i < ARRAY_SIZE(pkmap_map_wait_arr); ++i)
		init_waitqueue_head(pkmap_map_wait_arr + i);
}
#else
static inline void kmap_waitqueues_init(void)
{
}
#endif

static inline enum fixed_addresses kmap_idx(int type, unsigned long color)
{
	return (type + KM_TYPE_NR * smp_processor_id()) * DCACHE_N_COLORS +
		color;
}

void *kmap_atomic(struct page *page)
{
	enum fixed_addresses idx;
	unsigned long vaddr;

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

	idx = kmap_idx(kmap_atomic_idx_push(),
		       DCACHE_ALIAS(page_to_phys(page)));
	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_EXEC));

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

void __kunmap_atomic(void *kvaddr)
{
	if (kvaddr >= (void *)FIXADDR_START &&
	    kvaddr < (void *)FIXADDR_TOP) {
		int idx = kmap_idx(kmap_atomic_idx(),
				   DCACHE_ALIAS((unsigned long)kvaddr));

		/*
		 * 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.
		 */
		pte_clear(&init_mm, kvaddr, kmap_pte + idx);
		local_flush_tlb_kernel_range((unsigned long)kvaddr,
					     (unsigned long)kvaddr + PAGE_SIZE);

		kmap_atomic_idx_pop();
	}

	pagefault_enable();
	preempt_enable();
}
EXPORT_SYMBOL(__kunmap_atomic);

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);
	kmap_waitqueues_init();
}
Commit	Line	Data
65559100 MF	1	/*
	2	* High memory support for Xtensa architecture
	3	*
	4	* This file is subject to the terms and conditions of the GNU General
	5	* Public License. See the file "COPYING" in the main directory of
	6	* this archive for more details.
	7	*
	8	* Copyright (C) 2014 Cadence Design Systems Inc.
	9	*/
	10
	11	#include <linux/export.h>
	12	#include <linux/highmem.h>
	13	#include <asm/tlbflush.h>
	14
	15	static pte_t *kmap_pte;
	16
8504b503 MF	17	#if DCACHE_WAY_SIZE > PAGE_SIZE
	18	unsigned int last_pkmap_nr_arr[DCACHE_N_COLORS];
	19	wait_queue_head_t pkmap_map_wait_arr[DCACHE_N_COLORS];
	20
	21	static void __init kmap_waitqueues_init(void)
	22	{
	23	unsigned int i;
	24
	25	for (i = 0; i < ARRAY_SIZE(pkmap_map_wait_arr); ++i)
	26	init_waitqueue_head(pkmap_map_wait_arr + i);
	27	}
	28	#else
	29	static inline void kmap_waitqueues_init(void)
	30	{
	31	}
	32	#endif
	33
32544d9c MF	34	static inline enum fixed_addresses kmap_idx(int type, unsigned long color)
	35	{
	36	return (type + KM_TYPE_NR * smp_processor_id()) * DCACHE_N_COLORS +
	37	color;
	38	}
	39
65559100 MF	40	void kmap_atomic(struct page page)
	41	{
	42	enum fixed_addresses idx;
	43	unsigned long vaddr;
65559100	44
2cb7c9cb	45	preempt_disable();
65559100 MF	46	pagefault_disable();
	47	if (!PageHighMem(page))
	48	return page_address(page);
	49
32544d9c MF	50	idx = kmap_idx(kmap_atomic_idx_push(),
32544d9c MF	51	DCACHE_ALIAS(page_to_phys(page)));
65559100 MF	52	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
65559100 MF	53	#ifdef CONFIG_DEBUG_HIGHMEM
22def768	54	BUG_ON(!pte_none(*(kmap_pte + idx)));
65559100	55	#endif
22def768	56	set_pte(kmap_pte + idx, mk_pte(page, PAGE_KERNEL_EXEC));
65559100 MF	57
	58	return (void *)vaddr;
	59	}
	60	EXPORT_SYMBOL(kmap_atomic);
	61
	62	void __kunmap_atomic(void *kvaddr)
	63	{
65559100 MF	64	if (kvaddr >= (void *)FIXADDR_START &&
65559100 MF	65	kvaddr < (void *)FIXADDR_TOP) {
32544d9c MF	66	int idx = kmap_idx(kmap_atomic_idx(),
32544d9c MF	67	DCACHE_ALIAS((unsigned long)kvaddr));
65559100 MF	68
	69	/*
	70	* Force other mappings to Oops if they'll try to access this
	71	* pte without first remap it. Keeping stale mappings around
	72	* is a bad idea also, in case the page changes cacheability
	73	* attributes or becomes a protected page in a hypervisor.
	74	*/
22def768	75	pte_clear(&init_mm, kvaddr, kmap_pte + idx);
65559100 MF	76	local_flush_tlb_kernel_range((unsigned long)kvaddr,
	77	(unsigned long)kvaddr + PAGE_SIZE);
	78
	79	kmap_atomic_idx_pop();
	80	}
	81
	82	pagefault_enable();
2cb7c9cb	83	preempt_enable();
65559100 MF	84	}
	85	EXPORT_SYMBOL(__kunmap_atomic);
	86
	87	void __init kmap_init(void)
	88	{
	89	unsigned long kmap_vstart;
	90
	91	/* cache the first kmap pte */
	92	kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
	93	kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
8504b503	94	kmap_waitqueues_init();
65559100	95	}