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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" <[email protected]> Cc: Ross Zwisler <[email protected]> Reviewed-by: Christoph Hellwig <[email protected]> Reviewed-by: Jan Kara <[email protected]> Signed-off-by: Dan Williams <[email protected]>
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3 files changed

+171
-177
lines changed

3 files changed

+171
-177
lines changed

‎kernel/Makefile

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -112,7 +112,8 @@ obj-$(CONFIG_JUMP_LABEL) += jump_label.o
112112
obj-$(CONFIG_CONTEXT_TRACKING) += context_tracking.o
113113
obj-$(CONFIG_TORTURE_TEST) += torture.o
114114

115-
obj-$(CONFIG_HAS_IOMEM) += memremap.o
115+
obj-$(CONFIG_HAS_IOMEM) += iomem.o
116+
obj-$(CONFIG_ZONE_DEVICE) += memremap.o
116117

117118
$(obj)/configs.o: $(obj)/config_data.h
118119

‎kernel/iomem.c

Lines changed: 167 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,167 @@
1+
/* SPDX-License-Identifier: GPL-2.0 */
2+
#include <linux/device.h>
3+
#include <linux/types.h>
4+
#include <linux/io.h>
5+
#include <linux/mm.h>
6+
7+
#ifndef ioremap_cache
8+
/* temporary while we convert existing ioremap_cache users to memremap */
9+
__weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size)
10+
{
11+
return ioremap(offset, size);
12+
}
13+
#endif
14+
15+
#ifndef arch_memremap_wb
16+
static void *arch_memremap_wb(resource_size_t offset, unsigned long size)
17+
{
18+
return (__force void *)ioremap_cache(offset, size);
19+
}
20+
#endif
21+
22+
#ifndef arch_memremap_can_ram_remap
23+
static bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size,
24+
unsigned long flags)
25+
{
26+
return true;
27+
}
28+
#endif
29+
30+
static void *try_ram_remap(resource_size_t offset, size_t size,
31+
unsigned long flags)
32+
{
33+
unsigned long pfn = PHYS_PFN(offset);
34+
35+
/* In the simple case just return the existing linear address */
36+
if (pfn_valid(pfn) && !PageHighMem(pfn_to_page(pfn)) &&
37+
arch_memremap_can_ram_remap(offset, size, flags))
38+
return __va(offset);
39+
40+
return NULL; /* fallback to arch_memremap_wb */
41+
}
42+
43+
/**
44+
* memremap() - remap an iomem_resource as cacheable memory
45+
* @offset: iomem resource start address
46+
* @size: size of remap
47+
* @flags: any of MEMREMAP_WB, MEMREMAP_WT, MEMREMAP_WC,
48+
* MEMREMAP_ENC, MEMREMAP_DEC
49+
*
50+
* memremap() is "ioremap" for cases where it is known that the resource
51+
* being mapped does not have i/o side effects and the __iomem
52+
* annotation is not applicable. In the case of multiple flags, the different
53+
* mapping types will be attempted in the order listed below until one of
54+
* them succeeds.
55+
*
56+
* MEMREMAP_WB - matches the default mapping for System RAM on
57+
* the architecture. This is usually a read-allocate write-back cache.
58+
* Morever, if MEMREMAP_WB is specified and the requested remap region is RAM
59+
* memremap() will bypass establishing a new mapping and instead return
60+
* a pointer into the direct map.
61+
*
62+
* MEMREMAP_WT - establish a mapping whereby writes either bypass the
63+
* cache or are written through to memory and never exist in a
64+
* cache-dirty state with respect to program visibility. Attempts to
65+
* map System RAM with this mapping type will fail.
66+
*
67+
* MEMREMAP_WC - establish a writecombine mapping, whereby writes may
68+
* be coalesced together (e.g. in the CPU's write buffers), but is otherwise
69+
* uncached. Attempts to map System RAM with this mapping type will fail.
70+
*/
71+
void *memremap(resource_size_t offset, size_t size, unsigned long flags)
72+
{
73+
int is_ram = region_intersects(offset, size,
74+
IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
75+
void *addr = NULL;
76+
77+
if (!flags)
78+
return NULL;
79+
80+
if (is_ram == REGION_MIXED) {
81+
WARN_ONCE(1, "memremap attempted on mixed range %pa size: %#lx\n",
82+
&offset, (unsigned long) size);
83+
return NULL;
84+
}
85+
86+
/* Try all mapping types requested until one returns non-NULL */
87+
if (flags & MEMREMAP_WB) {
88+
/*
89+
* MEMREMAP_WB is special in that it can be satisifed
90+
* from the direct map. Some archs depend on the
91+
* capability of memremap() to autodetect cases where
92+
* the requested range is potentially in System RAM.
93+
*/
94+
if (is_ram == REGION_INTERSECTS)
95+
addr = try_ram_remap(offset, size, flags);
96+
if (!addr)
97+
addr = arch_memremap_wb(offset, size);
98+
}
99+
100+
/*
101+
* If we don't have a mapping yet and other request flags are
102+
* present then we will be attempting to establish a new virtual
103+
* address mapping. Enforce that this mapping is not aliasing
104+
* System RAM.
105+
*/
106+
if (!addr && is_ram == REGION_INTERSECTS && flags != MEMREMAP_WB) {
107+
WARN_ONCE(1, "memremap attempted on ram %pa size: %#lx\n",
108+
&offset, (unsigned long) size);
109+
return NULL;
110+
}
111+
112+
if (!addr && (flags & MEMREMAP_WT))
113+
addr = ioremap_wt(offset, size);
114+
115+
if (!addr && (flags & MEMREMAP_WC))
116+
addr = ioremap_wc(offset, size);
117+
118+
return addr;
119+
}
120+
EXPORT_SYMBOL(memremap);
121+
122+
void memunmap(void *addr)
123+
{
124+
if (is_vmalloc_addr(addr))
125+
iounmap((void __iomem *) addr);
126+
}
127+
EXPORT_SYMBOL(memunmap);
128+
129+
static void devm_memremap_release(struct device *dev, void *res)
130+
{
131+
memunmap(*(void **)res);
132+
}
133+
134+
static int devm_memremap_match(struct device *dev, void *res, void *match_data)
135+
{
136+
return *(void **)res == match_data;
137+
}
138+
139+
void *devm_memremap(struct device *dev, resource_size_t offset,
140+
size_t size, unsigned long flags)
141+
{
142+
void **ptr, *addr;
143+
144+
ptr = devres_alloc_node(devm_memremap_release, sizeof(*ptr), GFP_KERNEL,
145+
dev_to_node(dev));
146+
if (!ptr)
147+
return ERR_PTR(-ENOMEM);
148+
149+
addr = memremap(offset, size, flags);
150+
if (addr) {
151+
*ptr = addr;
152+
devres_add(dev, ptr);
153+
} else {
154+
devres_free(ptr);
155+
return ERR_PTR(-ENXIO);
156+
}
157+
158+
return addr;
159+
}
160+
EXPORT_SYMBOL(devm_memremap);
161+
162+
void devm_memunmap(struct device *dev, void *addr)
163+
{
164+
WARN_ON(devres_release(dev, devm_memremap_release,
165+
devm_memremap_match, addr));
166+
}
167+
EXPORT_SYMBOL(devm_memunmap);

‎kernel/memremap.c

Lines changed: 2 additions & 176 deletions
Original file line numberDiff line numberDiff line change
@@ -1,15 +1,5 @@
1-
/*
2-
* Copyright(c) 2015 Intel Corporation. All rights reserved.
3-
*
4-
* This program is free software; you can redistribute it and/or modify
5-
* it under the terms of version 2 of the GNU General Public License as
6-
* published by the Free Software Foundation.
7-
*
8-
* This program is distributed in the hope that it will be useful, but
9-
* WITHOUT ANY WARRANTY; without even the implied warranty of
10-
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11-
* General Public License for more details.
12-
*/
1+
/* SPDX-License-Identifier: GPL-2.0 */
2+
/* Copyright(c) 2015 Intel Corporation. All rights reserved. */
133
#include <linux/radix-tree.h>
144
#include <linux/device.h>
155
#include <linux/types.h>
@@ -20,169 +10,6 @@
2010
#include <linux/swap.h>
2111
#include <linux/swapops.h>
2212

23-
#ifndef ioremap_cache
24-
/* temporary while we convert existing ioremap_cache users to memremap */
25-
__weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size)
26-
{
27-
return ioremap(offset, size);
28-
}
29-
#endif
30-
31-
#ifndef arch_memremap_wb
32-
static void *arch_memremap_wb(resource_size_t offset, unsigned long size)
33-
{
34-
return (__force void *)ioremap_cache(offset, size);
35-
}
36-
#endif
37-
38-
#ifndef arch_memremap_can_ram_remap
39-
static bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size,
40-
unsigned long flags)
41-
{
42-
return true;
43-
}
44-
#endif
45-
46-
static void *try_ram_remap(resource_size_t offset, size_t size,
47-
unsigned long flags)
48-
{
49-
unsigned long pfn = PHYS_PFN(offset);
50-
51-
/* In the simple case just return the existing linear address */
52-
if (pfn_valid(pfn) && !PageHighMem(pfn_to_page(pfn)) &&
53-
arch_memremap_can_ram_remap(offset, size, flags))
54-
return __va(offset);
55-
56-
return NULL; /* fallback to arch_memremap_wb */
57-
}
58-
59-
/**
60-
* memremap() - remap an iomem_resource as cacheable memory
61-
* @offset: iomem resource start address
62-
* @size: size of remap
63-
* @flags: any of MEMREMAP_WB, MEMREMAP_WT, MEMREMAP_WC,
64-
* MEMREMAP_ENC, MEMREMAP_DEC
65-
*
66-
* memremap() is "ioremap" for cases where it is known that the resource
67-
* being mapped does not have i/o side effects and the __iomem
68-
* annotation is not applicable. In the case of multiple flags, the different
69-
* mapping types will be attempted in the order listed below until one of
70-
* them succeeds.
71-
*
72-
* MEMREMAP_WB - matches the default mapping for System RAM on
73-
* the architecture. This is usually a read-allocate write-back cache.
74-
* Morever, if MEMREMAP_WB is specified and the requested remap region is RAM
75-
* memremap() will bypass establishing a new mapping and instead return
76-
* a pointer into the direct map.
77-
*
78-
* MEMREMAP_WT - establish a mapping whereby writes either bypass the
79-
* cache or are written through to memory and never exist in a
80-
* cache-dirty state with respect to program visibility. Attempts to
81-
* map System RAM with this mapping type will fail.
82-
*
83-
* MEMREMAP_WC - establish a writecombine mapping, whereby writes may
84-
* be coalesced together (e.g. in the CPU's write buffers), but is otherwise
85-
* uncached. Attempts to map System RAM with this mapping type will fail.
86-
*/
87-
void *memremap(resource_size_t offset, size_t size, unsigned long flags)
88-
{
89-
int is_ram = region_intersects(offset, size,
90-
IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
91-
void *addr = NULL;
92-
93-
if (!flags)
94-
return NULL;
95-
96-
if (is_ram == REGION_MIXED) {
97-
WARN_ONCE(1, "memremap attempted on mixed range %pa size: %#lx\n",
98-
&offset, (unsigned long) size);
99-
return NULL;
100-
}
101-
102-
/* Try all mapping types requested until one returns non-NULL */
103-
if (flags & MEMREMAP_WB) {
104-
/*
105-
* MEMREMAP_WB is special in that it can be satisifed
106-
* from the direct map. Some archs depend on the
107-
* capability of memremap() to autodetect cases where
108-
* the requested range is potentially in System RAM.
109-
*/
110-
if (is_ram == REGION_INTERSECTS)
111-
addr = try_ram_remap(offset, size, flags);
112-
if (!addr)
113-
addr = arch_memremap_wb(offset, size);
114-
}
115-
116-
/*
117-
* If we don't have a mapping yet and other request flags are
118-
* present then we will be attempting to establish a new virtual
119-
* address mapping. Enforce that this mapping is not aliasing
120-
* System RAM.
121-
*/
122-
if (!addr && is_ram == REGION_INTERSECTS && flags != MEMREMAP_WB) {
123-
WARN_ONCE(1, "memremap attempted on ram %pa size: %#lx\n",
124-
&offset, (unsigned long) size);
125-
return NULL;
126-
}
127-
128-
if (!addr && (flags & MEMREMAP_WT))
129-
addr = ioremap_wt(offset, size);
130-
131-
if (!addr && (flags & MEMREMAP_WC))
132-
addr = ioremap_wc(offset, size);
133-
134-
return addr;
135-
}
136-
EXPORT_SYMBOL(memremap);
137-
138-
void memunmap(void *addr)
139-
{
140-
if (is_vmalloc_addr(addr))
141-
iounmap((void __iomem *) addr);
142-
}
143-
EXPORT_SYMBOL(memunmap);
144-
145-
static void devm_memremap_release(struct device *dev, void *res)
146-
{
147-
memunmap(*(void **)res);
148-
}
149-
150-
static int devm_memremap_match(struct device *dev, void *res, void *match_data)
151-
{
152-
return *(void **)res == match_data;
153-
}
154-
155-
void *devm_memremap(struct device *dev, resource_size_t offset,
156-
size_t size, unsigned long flags)
157-
{
158-
void **ptr, *addr;
159-
160-
ptr = devres_alloc_node(devm_memremap_release, sizeof(*ptr), GFP_KERNEL,
161-
dev_to_node(dev));
162-
if (!ptr)
163-
return ERR_PTR(-ENOMEM);
164-
165-
addr = memremap(offset, size, flags);
166-
if (addr) {
167-
*ptr = addr;
168-
devres_add(dev, ptr);
169-
} else {
170-
devres_free(ptr);
171-
return ERR_PTR(-ENXIO);
172-
}
173-
174-
return addr;
175-
}
176-
EXPORT_SYMBOL(devm_memremap);
177-
178-
void devm_memunmap(struct device *dev, void *addr)
179-
{
180-
WARN_ON(devres_release(dev, devm_memremap_release,
181-
devm_memremap_match, addr));
182-
}
183-
EXPORT_SYMBOL(devm_memunmap);
184-
185-
#ifdef CONFIG_ZONE_DEVICE
18613
static DEFINE_MUTEX(pgmap_lock);
18714
static RADIX_TREE(pgmap_radix, GFP_KERNEL);
18815
#define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1)
@@ -473,7 +300,6 @@ struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
473300

474301
return pgmap;
475302
}
476-
#endif /* CONFIG_ZONE_DEVICE */
477303

478304
#if IS_ENABLED(CONFIG_DEVICE_PRIVATE) || IS_ENABLED(CONFIG_DEVICE_PUBLIC)
479305
void put_zone_device_private_or_public_page(struct page *page)

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