[mirror_ubuntu-bionic-kernel.git] / arch / microblaze / mm / highmem.c

// SPDX-License-Identifier: GPL-2.0
/*
 * highmem.c: virtual kernel memory mappings for high memory
 *
 * PowerPC version, stolen from the i386 version.
 *
 * Used in CONFIG_HIGHMEM systems for memory pages which
 * are not addressable by direct kernel virtual addresses.
 *
 * Copyright (C) 1999 Gerhard Wichert, Siemens AG
 *		      Gerhard.Wichert@pdb.siemens.de
 *
 *
 * Redesigned the x86 32-bit VM architecture to deal with
 * up to 16 Terrabyte physical memory. With current x86 CPUs
 * we now support up to 64 Gigabytes physical RAM.
 *
 * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
 *
 * Reworked for PowerPC by various contributors. Moved from
 * highmem.h by Benjamin Herrenschmidt (c) 2009 IBM Corp.
 */

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

/*
 * 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.
 */
#include <asm/tlbflush.h>

void *kmap_atomic_prot(struct page *page, pgprot_t prot)
{

	unsigned long vaddr;
	int idx, type;

	preempt_disable();
	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_at(&init_mm, vaddr, kmap_pte-idx, mk_pte(page, prot));
	local_flush_tlb_page(NULL, vaddr);

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

void __kunmap_atomic(void *kvaddr)
{
	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
	int type;
	unsigned int idx;

	if (vaddr < __fix_to_virt(FIX_KMAP_END)) {
		pagefault_enable();
		preempt_enable();
		return;
	}

	type = kmap_atomic_idx();

	idx = type + KM_TYPE_NR * smp_processor_id();
#ifdef CONFIG_DEBUG_HIGHMEM
	BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
#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);
	local_flush_tlb_page(NULL, vaddr);

	kmap_atomic_idx_pop();
	pagefault_enable();
	preempt_enable();
}
EXPORT_SYMBOL(__kunmap_atomic);
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
2f2f371f MS	2	/*
	3	* highmem.c: virtual kernel memory mappings for high memory
	4	*
	5	* PowerPC version, stolen from the i386 version.
	6	*
	7	* Used in CONFIG_HIGHMEM systems for memory pages which
	8	* are not addressable by direct kernel virtual addresses.
	9	*
	10	* Copyright (C) 1999 Gerhard Wichert, Siemens AG
	11	* Gerhard.Wichert@pdb.siemens.de
	12	*
	13	*
	14	* Redesigned the x86 32-bit VM architecture to deal with
	15	* up to 16 Terrabyte physical memory. With current x86 CPUs
	16	* we now support up to 64 Gigabytes physical RAM.
	17	*
	18	* Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
	19	*
	20	* Reworked for PowerPC by various contributors. Moved from
	21	* highmem.h by Benjamin Herrenschmidt (c) 2009 IBM Corp.
	22	*/
	23
d64af918	24	#include <linux/export.h>
2f2f371f	25	#include <linux/highmem.h>
2f2f371f MS	26
	27	/*
	28	* The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
	29	* gives a more generic (and caching) interface. But kmap_atomic can
	30	* be used in IRQ contexts, so in some (very limited) cases we need
	31	* it.
	32	*/
	33	#include <asm/tlbflush.h>
	34
	35	void kmap_atomic_prot(struct page page, pgprot_t prot)
	36	{
	37
	38	unsigned long vaddr;
	39	int idx, type;
	40
2cb7c9cb	41	preempt_disable();
2f2f371f MS	42	pagefault_disable();
	43	if (!PageHighMem(page))
	44	return page_address(page);
	45
	46
	47	type = kmap_atomic_idx_push();
	48	idx = type + KM_TYPE_NR*smp_processor_id();
	49	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
	50	#ifdef CONFIG_DEBUG_HIGHMEM
	51	BUG_ON(!pte_none(*(kmap_pte-idx)));
	52	#endif
	53	set_pte_at(&init_mm, vaddr, kmap_pte-idx, mk_pte(page, prot));
	54	local_flush_tlb_page(NULL, vaddr);
	55
	56	return (void *) vaddr;
	57	}
	58	EXPORT_SYMBOL(kmap_atomic_prot);
	59
	60	void __kunmap_atomic(void *kvaddr)
	61	{
	62	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
	63	int type;
a753499d	64	unsigned int idx;
2f2f371f MS	65
	66	if (vaddr < __fix_to_virt(FIX_KMAP_END)) {
	67	pagefault_enable();
2cb7c9cb	68	preempt_enable();
2f2f371f MS	69	return;
	70	}
	71
	72	type = kmap_atomic_idx();
2f2f371f	73
a753499d MS	74	idx = type + KM_TYPE_NR * smp_processor_id();
	75	#ifdef CONFIG_DEBUG_HIGHMEM
	76	BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
2f2f371f	77	#endif
a753499d MS	78	/*
	79	* force other mappings to Oops if they'll try to access
	80	* this pte without first remap it
	81	*/
	82	pte_clear(&init_mm, vaddr, kmap_pte-idx);
	83	local_flush_tlb_page(NULL, vaddr);
	84
2f2f371f MS	85	kmap_atomic_idx_pop();
2f2f371f MS	86	pagefault_enable();
2cb7c9cb	87	preempt_enable();
2f2f371f MS	88	}
2f2f371f MS	89	EXPORT_SYMBOL(__kunmap_atomic);