Commit 5981690d authored by Dan Williams's avatar Dan Williams
Browse files

memremap: split devm_memremap_pages() and memremap() infrastructure 



Currently, kernel/memremap.c contains generic code for supporting
memremap() (CONFIG_HAS_IOMEM) and devm_memremap_pages()
(CONFIG_ZONE_DEVICE). This causes ongoing build maintenance problems as
additions to memremap.c, especially for the ZONE_DEVICE case, need to be
careful about being placed in ifdef guards. Remove the need for these
ifdef guards by moving the ZONE_DEVICE support functions to their own
compilation unit.

Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 6d08b06e

kernel/Makefile

+2 −1
Original line number Diff line number Diff line
@@ -112,7 +112,8 @@ obj-$(CONFIG_JUMP_LABEL) += jump_label.o 
obj-$(CONFIG_CONTEXT_TRACKING) += context_tracking.o

obj-$(CONFIG_TORTURE_TEST) += torture.o



obj-$(CONFIG_HAS_IOMEM) += memremap.o

obj-$(CONFIG_HAS_IOMEM) += iomem.o

obj-$(CONFIG_ZONE_DEVICE) += memremap.o



$(obj)/configs.o: $(obj)/config_data.h

kernel/iomem.c

0 → 100644
+167 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#include <linux/device.h>

#include <linux/types.h>

#include <linux/io.h>

#include <linux/mm.h>



#ifndef ioremap_cache

/* temporary while we convert existing ioremap_cache users to memremap */

__weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size)

{

	return ioremap(offset, size);

}

#endif



#ifndef arch_memremap_wb

static void *arch_memremap_wb(resource_size_t offset, unsigned long size)

{

	return (__force void *)ioremap_cache(offset, size);

}

#endif



#ifndef arch_memremap_can_ram_remap

static bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size,

					unsigned long flags)

{

	return true;

}

#endif



static void *try_ram_remap(resource_size_t offset, size_t size,

			   unsigned long flags)

{

	unsigned long pfn = PHYS_PFN(offset);



	/* In the simple case just return the existing linear address */

	if (pfn_valid(pfn) && !PageHighMem(pfn_to_page(pfn)) &&

	    arch_memremap_can_ram_remap(offset, size, flags))

		return __va(offset);



	return NULL; /* fallback to arch_memremap_wb */

}



/**

 * memremap() - remap an iomem_resource as cacheable memory

 * @offset: iomem resource start address

 * @size: size of remap

 * @flags: any of MEMREMAP_WB, MEMREMAP_WT, MEMREMAP_WC,

 *		  MEMREMAP_ENC, MEMREMAP_DEC

 *

 * memremap() is "ioremap" for cases where it is known that the resource

 * being mapped does not have i/o side effects and the __iomem

 * annotation is not applicable. In the case of multiple flags, the different

 * mapping types will be attempted in the order listed below until one of

 * them succeeds.

 *

 * MEMREMAP_WB - matches the default mapping for System RAM on

 * the architecture.  This is usually a read-allocate write-back cache.

 * Morever, if MEMREMAP_WB is specified and the requested remap region is RAM

 * memremap() will bypass establishing a new mapping and instead return

 * a pointer into the direct map.

 *

 * MEMREMAP_WT - establish a mapping whereby writes either bypass the

 * cache or are written through to memory and never exist in a

 * cache-dirty state with respect to program visibility.  Attempts to

 * map System RAM with this mapping type will fail.

 *

 * MEMREMAP_WC - establish a writecombine mapping, whereby writes may

 * be coalesced together (e.g. in the CPU's write buffers), but is otherwise

 * uncached. Attempts to map System RAM with this mapping type will fail.

 */

void *memremap(resource_size_t offset, size_t size, unsigned long flags)

{

	int is_ram = region_intersects(offset, size,

				       IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);

	void *addr = NULL;



	if (!flags)

		return NULL;



	if (is_ram == REGION_MIXED) {

		WARN_ONCE(1, "memremap attempted on mixed range %pa size: %#lx\n",

				&offset, (unsigned long) size);

		return NULL;

	}



	/* Try all mapping types requested until one returns non-NULL */

	if (flags & MEMREMAP_WB) {

		/*

		 * MEMREMAP_WB is special in that it can be satisifed

		 * from the direct map.  Some archs depend on the

		 * capability of memremap() to autodetect cases where

		 * the requested range is potentially in System RAM.

		 */

		if (is_ram == REGION_INTERSECTS)

			addr = try_ram_remap(offset, size, flags);

		if (!addr)

			addr = arch_memremap_wb(offset, size);

	}



	/*

	 * If we don't have a mapping yet and other request flags are

	 * present then we will be attempting to establish a new virtual

	 * address mapping.  Enforce that this mapping is not aliasing

	 * System RAM.

	 */

	if (!addr && is_ram == REGION_INTERSECTS && flags != MEMREMAP_WB) {

		WARN_ONCE(1, "memremap attempted on ram %pa size: %#lx\n",

				&offset, (unsigned long) size);

		return NULL;

	}



	if (!addr && (flags & MEMREMAP_WT))

		addr = ioremap_wt(offset, size);



	if (!addr && (flags & MEMREMAP_WC))

		addr = ioremap_wc(offset, size);



	return addr;

}

EXPORT_SYMBOL(memremap);



void memunmap(void *addr)

{

	if (is_vmalloc_addr(addr))

		iounmap((void __iomem *) addr);

}

EXPORT_SYMBOL(memunmap);



static void devm_memremap_release(struct device *dev, void *res)

{

	memunmap(*(void **)res);

}



static int devm_memremap_match(struct device *dev, void *res, void *match_data)

{

	return *(void **)res == match_data;

}



void *devm_memremap(struct device *dev, resource_size_t offset,

		size_t size, unsigned long flags)

{

	void **ptr, *addr;



	ptr = devres_alloc_node(devm_memremap_release, sizeof(*ptr), GFP_KERNEL,

			dev_to_node(dev));

	if (!ptr)

		return ERR_PTR(-ENOMEM);



	addr = memremap(offset, size, flags);

	if (addr) {

		*ptr = addr;

		devres_add(dev, ptr);

	} else {

		devres_free(ptr);

		return ERR_PTR(-ENXIO);

	}



	return addr;

}

EXPORT_SYMBOL(devm_memremap);



void devm_memunmap(struct device *dev, void *addr)

{

	WARN_ON(devres_release(dev, devm_memremap_release,

				devm_memremap_match, addr));

}

EXPORT_SYMBOL(devm_memunmap);

kernel/memremap.c

+2 −176
Original line number Diff line number Diff line 
/*

 * Copyright(c) 2015 Intel Corporation. All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of version 2 of the GNU General Public License as

 * published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful, but

 * WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * General Public License for more details.

 */

/* SPDX-License-Identifier: GPL-2.0 */

/* Copyright(c) 2015 Intel Corporation. All rights reserved. */

#include <linux/radix-tree.h>

#include <linux/device.h>

#include <linux/types.h>
@@ -20,169 +10,6 @@ 
#include <linux/swap.h>

#include <linux/swapops.h>



#ifndef ioremap_cache

/* temporary while we convert existing ioremap_cache users to memremap */

__weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size)

{

	return ioremap(offset, size);

}

#endif



#ifndef arch_memremap_wb

static void *arch_memremap_wb(resource_size_t offset, unsigned long size)

{

	return (__force void *)ioremap_cache(offset, size);

}

#endif



#ifndef arch_memremap_can_ram_remap

static bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size,

					unsigned long flags)

{

	return true;

}

#endif



static void *try_ram_remap(resource_size_t offset, size_t size,

			   unsigned long flags)

{

	unsigned long pfn = PHYS_PFN(offset);



	/* In the simple case just return the existing linear address */

	if (pfn_valid(pfn) && !PageHighMem(pfn_to_page(pfn)) &&

	    arch_memremap_can_ram_remap(offset, size, flags))

		return __va(offset);



	return NULL; /* fallback to arch_memremap_wb */

}



/**

 * memremap() - remap an iomem_resource as cacheable memory

 * @offset: iomem resource start address

 * @size: size of remap

 * @flags: any of MEMREMAP_WB, MEMREMAP_WT, MEMREMAP_WC,

 *		  MEMREMAP_ENC, MEMREMAP_DEC

 *

 * memremap() is "ioremap" for cases where it is known that the resource

 * being mapped does not have i/o side effects and the __iomem

 * annotation is not applicable. In the case of multiple flags, the different

 * mapping types will be attempted in the order listed below until one of

 * them succeeds.

 *

 * MEMREMAP_WB - matches the default mapping for System RAM on

 * the architecture.  This is usually a read-allocate write-back cache.

 * Morever, if MEMREMAP_WB is specified and the requested remap region is RAM

 * memremap() will bypass establishing a new mapping and instead return

 * a pointer into the direct map.

 *

 * MEMREMAP_WT - establish a mapping whereby writes either bypass the

 * cache or are written through to memory and never exist in a

 * cache-dirty state with respect to program visibility.  Attempts to

 * map System RAM with this mapping type will fail.

 *

 * MEMREMAP_WC - establish a writecombine mapping, whereby writes may

 * be coalesced together (e.g. in the CPU's write buffers), but is otherwise

 * uncached. Attempts to map System RAM with this mapping type will fail.

 */

void *memremap(resource_size_t offset, size_t size, unsigned long flags)

{

	int is_ram = region_intersects(offset, size,

				       IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);

	void *addr = NULL;



	if (!flags)

		return NULL;



	if (is_ram == REGION_MIXED) {

		WARN_ONCE(1, "memremap attempted on mixed range %pa size: %#lx\n",

				&offset, (unsigned long) size);

		return NULL;

	}



	/* Try all mapping types requested until one returns non-NULL */

	if (flags & MEMREMAP_WB) {

		/*

		 * MEMREMAP_WB is special in that it can be satisifed

		 * from the direct map.  Some archs depend on the

		 * capability of memremap() to autodetect cases where

		 * the requested range is potentially in System RAM.

		 */

		if (is_ram == REGION_INTERSECTS)

			addr = try_ram_remap(offset, size, flags);

		if (!addr)

			addr = arch_memremap_wb(offset, size);

	}



	/*

	 * If we don't have a mapping yet and other request flags are

	 * present then we will be attempting to establish a new virtual

	 * address mapping.  Enforce that this mapping is not aliasing

	 * System RAM.

	 */

	if (!addr && is_ram == REGION_INTERSECTS && flags != MEMREMAP_WB) {

		WARN_ONCE(1, "memremap attempted on ram %pa size: %#lx\n",

				&offset, (unsigned long) size);

		return NULL;

	}



	if (!addr && (flags & MEMREMAP_WT))

		addr = ioremap_wt(offset, size);



	if (!addr && (flags & MEMREMAP_WC))

		addr = ioremap_wc(offset, size);



	return addr;

}

EXPORT_SYMBOL(memremap);



void memunmap(void *addr)

{

	if (is_vmalloc_addr(addr))

		iounmap((void __iomem *) addr);

}

EXPORT_SYMBOL(memunmap);



static void devm_memremap_release(struct device *dev, void *res)

{

	memunmap(*(void **)res);

}



static int devm_memremap_match(struct device *dev, void *res, void *match_data)

{

	return *(void **)res == match_data;

}



void *devm_memremap(struct device *dev, resource_size_t offset,

		size_t size, unsigned long flags)

{

	void **ptr, *addr;



	ptr = devres_alloc_node(devm_memremap_release, sizeof(*ptr), GFP_KERNEL,

			dev_to_node(dev));

	if (!ptr)

		return ERR_PTR(-ENOMEM);



	addr = memremap(offset, size, flags);

	if (addr) {

		*ptr = addr;

		devres_add(dev, ptr);

	} else {

		devres_free(ptr);

		return ERR_PTR(-ENXIO);

	}



	return addr;

}

EXPORT_SYMBOL(devm_memremap);



void devm_memunmap(struct device *dev, void *addr)

{

	WARN_ON(devres_release(dev, devm_memremap_release,

				devm_memremap_match, addr));

}

EXPORT_SYMBOL(devm_memunmap);



#ifdef CONFIG_ZONE_DEVICE

static DEFINE_MUTEX(pgmap_lock);

static RADIX_TREE(pgmap_radix, GFP_KERNEL);

#define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1)
@@ -473,7 +300,6 @@ struct dev_pagemap *get_dev_pagemap(unsigned long pfn, 


	return pgmap;

}

#endif /* CONFIG_ZONE_DEVICE */



#if IS_ENABLED(CONFIG_DEVICE_PRIVATE) ||  IS_ENABLED(CONFIG_DEVICE_PUBLIC)

void put_zone_device_private_or_public_page(struct page *page)

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