[PATCH v5 5/6] arch: introduce memremap_cache() and memremap_wt()

Dan Williams
2015-06-22T08:31:01Z

Existing users of ioremap_cache() are mapping memory that is known in
advance to not have i/o side effects. These users are forced to cast
away the __iomem annotation, or otherwise neglect to fix the sparse
errors thrown when dereferencing pointers to this memory. Provide
memremap_*() as a non __iomem annotated ioremap_*().

The ARCH_HAS_MEMREMAP kconfig symbol is introduced for archs to assert
that it is safe to recast / reuse the return value from ioremap as a
normal pointer to memory. In other words, archs that mandate specific
accessors for __iomem are not memremap() capable and drivers that care,
like pmem, can add a dependency to disable themselves on these archs.

Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
arch/arm/Kconfig | 1 +
arch/arm64/Kconfig | 1 +
arch/arm64/kernel/efi.c | 4 ++-
arch/arm64/kernel/smp_spin_table.c | 10 ++++----
arch/frv/Kconfig | 1 +
arch/m68k/Kconfig | 1 +
arch/metag/Kconfig | 1 +
arch/mips/Kconfig | 1 +
arch/powerpc/Kconfig | 1 +
arch/x86/Kconfig | 1 +
arch/x86/kernel/crash_dump_64.c | 6 ++---
arch/x86/kernel/kdebugfs.c | 8 +++----
arch/x86/kernel/ksysfs.c | 28 ++++++++++++-----------
arch/x86/mm/ioremap.c | 10 +++-----
arch/xtensa/Kconfig | 1 +
drivers/acpi/apei/einj.c | 8 +++----
drivers/acpi/apei/erst.c | 4 ++-
drivers/block/Kconfig | 1 +
drivers/block/pmem.c | 7 +++---
drivers/firmware/google/memconsole.c | 4 ++-
include/linux/device.h | 5 ++++
include/linux/io.h | 4 +++
kernel/resource.c | 41 +++++++++++++++++++++++++++++++++-
lib/Kconfig | 5 +++-
24 files changed, 107 insertions(+), 47 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 45df48ba0b12..397426f8ca37 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -3,6 +3,7 @@ config ARM
default y
select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select ARCH_HAS_ELF_RANDOMIZE
+ select ARCH_HAS_MEMREMAP
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
select ARCH_HAVE_CUSTOM_GPIO_H
select ARCH_HAS_GCOV_PROFILE_ALL
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 7796af4b1d6f..f07a9a5af61e 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -5,6 +5,7 @@ config ARM64
select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select ARCH_HAS_ELF_RANDOMIZE
select ARCH_HAS_GCOV_PROFILE_ALL
+ select ARCH_HAS_MEMREMAP
select ARCH_HAS_SG_CHAIN
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
select ARCH_USE_CMPXCHG_LOCKREF
diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index ab21e0d58278..b672ef33f08b 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -289,7 +289,7 @@ static int __init arm64_enable_runtime_services(void)
pr_info("Remapping and enabling EFI services.\n");

mapsize = memmap.map_end - memmap.map;
- memmap.map = (__force void *)ioremap_cache((phys_addr_t)memmap.phys_map,
+ memmap.map = memremap_cache((phys_addr_t)memmap.phys_map,
mapsize);
if (!memmap.map) {
pr_err("Failed to remap EFI memory map\n");
@@ -298,7 +298,7 @@ static int __init arm64_enable_runtime_services(void)
memmap.map_end = memmap.map + mapsize;
efi.memmap = &memmap;

- efi.systab = (__force void *)ioremap_cache(efi_system_table,
+ efi.systab = memremap_cache(efi_system_table,
sizeof(efi_system_table_t));
if (!efi.systab) {
pr_err("Failed to remap EFI System Table\n");
diff --git a/arch/arm64/kernel/smp_spin_table.c b/arch/arm64/kernel/smp_spin_table.c
index 14944e5b28da..893c8586e20f 100644
--- a/arch/arm64/kernel/smp_spin_table.c
+++ b/arch/arm64/kernel/smp_spin_table.c
@@ -67,18 +67,18 @@ static int smp_spin_table_cpu_init(struct device_node *dn, unsigned int cpu)

static int smp_spin_table_cpu_prepare(unsigned int cpu)
{
- __le64 __iomem *release_addr;
+ __le64 *release_addr;

if (!cpu_release_addr[cpu])
return -ENODEV;

/*
* The cpu-release-addr may or may not be inside the linear mapping.
- * As ioremap_cache will either give us a new mapping or reuse the
+ * As memremap_cache will either give us a new mapping or reuse the
* existing linear mapping, we can use it to cover both cases. In
* either case the memory will be MT_NORMAL.
*/
- release_addr = ioremap_cache(cpu_release_addr[cpu],
+ release_addr = memremap_cache(cpu_release_addr[cpu],
sizeof(*release_addr));
if (!release_addr)
return -ENOMEM;
@@ -91,7 +91,7 @@ static int smp_spin_table_cpu_prepare(unsigned int cpu)
* the boot protocol.
*/
writeq_relaxed(__pa(secondary_holding_pen), release_addr);
- __flush_dcache_area((__force void *)release_addr,
+ __flush_dcache_area(release_addr,
sizeof(*release_addr));

/*
@@ -99,7 +99,7 @@ static int smp_spin_table_cpu_prepare(unsigned int cpu)
*/
sev();

- iounmap(release_addr);
+ memunmap(release_addr);

return 0;
}
diff --git a/arch/frv/Kconfig b/arch/frv/Kconfig
index 34aa19352dc1..2373bf183527 100644
--- a/arch/frv/Kconfig
+++ b/arch/frv/Kconfig
@@ -14,6 +14,7 @@ config FRV
select OLD_SIGSUSPEND3
select OLD_SIGACTION
select HAVE_DEBUG_STACKOVERFLOW
+ select ARCH_HAS_MEMREMAP

config ZONE_DMA
bool
diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index 2dd8f63bfbbb..831b1be8c43d 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -23,6 +23,7 @@ config M68K
select MODULES_USE_ELF_RELA
select OLD_SIGSUSPEND3
select OLD_SIGACTION
+ select ARCH_HAS_MEMREMAP

config RWSEM_GENERIC_SPINLOCK
bool
diff --git a/arch/metag/Kconfig b/arch/metag/Kconfig
index 0b389a81c43a..5669fe3eb807 100644
--- a/arch/metag/Kconfig
+++ b/arch/metag/Kconfig
@@ -24,6 +24,7 @@ config METAG
select HAVE_PERF_EVENTS
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_UNDERSCORE_SYMBOL_PREFIX
+ select ARCH_HAS_MEMREMAP
select IRQ_DOMAIN
select MODULES_USE_ELF_RELA
select OF
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index f5016656494f..9ee35e615c0d 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -58,6 +58,7 @@ config MIPS
select SYSCTL_EXCEPTION_TRACE
select HAVE_VIRT_CPU_ACCOUNTING_GEN
select HAVE_IRQ_TIME_ACCOUNTING
+ select ARCH_HAS_MEMREMAP

menu "Machine selection"

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 190cc48abc0c..73c1f8b1f022 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -153,6 +153,7 @@ config PPC
select NO_BOOTMEM
select HAVE_GENERIC_RCU_GUP
select HAVE_PERF_EVENTS_NMI if PPC64
+ select ARCH_HAS_MEMREMAP

config GENERIC_CSUM
def_bool CPU_LITTLE_ENDIAN
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 228aa35d7e89..f16caf7eac27 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -27,6 +27,7 @@ config X86
select ARCH_HAS_ELF_RANDOMIZE
select ARCH_HAS_FAST_MULTIPLIER
select ARCH_HAS_GCOV_PROFILE_ALL
+ select ARCH_HAS_MEMREMAP
select ARCH_HAS_SG_CHAIN
select ARCH_HAVE_NMI_SAFE_CMPXCHG
select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
diff --git a/arch/x86/kernel/crash_dump_64.c b/arch/x86/kernel/crash_dump_64.c
index afa64adb75ee..8e04011665fd 100644
--- a/arch/x86/kernel/crash_dump_64.c
+++ b/arch/x86/kernel/crash_dump_64.c
@@ -31,19 +31,19 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
if (!csize)
return 0;

- vaddr = ioremap_cache(pfn << PAGE_SHIFT, PAGE_SIZE);
+ vaddr = memremap_cache(pfn << PAGE_SHIFT, PAGE_SIZE);
if (!vaddr)
return -ENOMEM;

if (userbuf) {
if (copy_to_user(buf, vaddr + offset, csize)) {
- iounmap(vaddr);
+ memunmap(vaddr);
return -EFAULT;
}
} else
memcpy(buf, vaddr + offset, csize);

set_iounmap_nonlazy();
- iounmap(vaddr);
+ memunmap(vaddr);
return csize;
}
diff --git a/arch/x86/kernel/kdebugfs.c b/arch/x86/kernel/kdebugfs.c
index dc1404bf8e4b..731b10e2814f 100644
--- a/arch/x86/kernel/kdebugfs.c
+++ b/arch/x86/kernel/kdebugfs.c
@@ -49,7 +49,7 @@ static ssize_t setup_data_read(struct file *file, char __user *user_buf,
pa = node->paddr + sizeof(struct setup_data) + pos;
pg = pfn_to_page((pa + count - 1) >> PAGE_SHIFT);
if (PageHighMem(pg)) {
- p = ioremap_cache(pa, count);
+ p = memremap_cache(pa, count);
if (!p)
return -ENXIO;
} else
@@ -58,7 +58,7 @@ static ssize_t setup_data_read(struct file *file, char __user *user_buf,
remain = copy_to_user(user_buf, p, count);

if (PageHighMem(pg))
- iounmap(p);
+ memunmap(p);

if (remain)
return -EFAULT;
@@ -128,7 +128,7 @@ static int __init create_setup_data_nodes(struct dentry *parent)

pg = pfn_to_page((pa_data+sizeof(*data)-1) >> PAGE_SHIFT);
if (PageHighMem(pg)) {
- data = ioremap_cache(pa_data, sizeof(*data));
+ data = memremap_cache(pa_data, sizeof(*data));
if (!data) {
kfree(node);
error = -ENXIO;
@@ -144,7 +144,7 @@ static int __init create_setup_data_nodes(struct dentry *parent)
pa_data = data->next;

if (PageHighMem(pg))
- iounmap(data);
+ memunmap(data);
if (error)
goto err_dir;
no++;
diff --git a/arch/x86/kernel/ksysfs.c b/arch/x86/kernel/ksysfs.c
index c2bedaea11f7..2fbc62886eae 100644
--- a/arch/x86/kernel/ksysfs.c
+++ b/arch/x86/kernel/ksysfs.c
@@ -16,8 +16,8 @@
#include <linux/stat.h>
#include <linux/slab.h>
#include <linux/mm.h>
+#include <linux/io.h>

-#include <asm/io.h>
#include <asm/setup.h>

static ssize_t version_show(struct kobject *kobj,
@@ -79,12 +79,12 @@ static int get_setup_data_paddr(int nr, u64 *paddr)
*paddr = pa_data;
return 0;
}
- data = ioremap_cache(pa_data, sizeof(*data));
+ data = memremap_cache(pa_data, sizeof(*data));
if (!data)
return -ENOMEM;

pa_data = data->next;
- iounmap(data);
+ memunmap(data);
i++;
}
return -EINVAL;
@@ -97,17 +97,17 @@ static int __init get_setup_data_size(int nr, size_t *size)
u64 pa_data = boot_params.hdr.setup_data;

while (pa_data) {
- data = ioremap_cache(pa_data, sizeof(*data));
+ data = memremap_cache(pa_data, sizeof(*data));
if (!data)
return -ENOMEM;
if (nr == i) {
*size = data->len;
- iounmap(data);
+ memunmap(data);
return 0;
}

pa_data = data->next;
- iounmap(data);
+ memunmap(data);
i++;
}
return -EINVAL;
@@ -127,12 +127,12 @@ static ssize_t type_show(struct kobject *kobj,
ret = get_setup_data_paddr(nr, &paddr);
if (ret)
return ret;
- data = ioremap_cache(paddr, sizeof(*data));
+ data = memremap_cache(paddr, sizeof(*data));
if (!data)
return -ENOMEM;

ret = sprintf(buf, "0x%x\n", data->type);
- iounmap(data);
+ memunmap(data);
return ret;
}

@@ -154,7 +154,7 @@ static ssize_t setup_data_data_read(struct file *fp,
ret = get_setup_data_paddr(nr, &paddr);
if (ret)
return ret;
- data = ioremap_cache(paddr, sizeof(*data));
+ data = memremap_cache(paddr, sizeof(*data));
if (!data)
return -ENOMEM;

@@ -170,15 +170,15 @@ static ssize_t setup_data_data_read(struct file *fp,
goto out;

ret = count;
- p = ioremap_cache(paddr + sizeof(*data), data->len);
+ p = memremap_cache(paddr + sizeof(*data), data->len);
if (!p) {
ret = -ENOMEM;
goto out;
}
memcpy(buf, p + off, count);
- iounmap(p);
+ memunmap(p);
out:
- iounmap(data);
+ memunmap(data);
return ret;
}

@@ -250,13 +250,13 @@ static int __init get_setup_data_total_num(u64 pa_data, int *nr)
*nr = 0;
while (pa_data) {
*nr += 1;
- data = ioremap_cache(pa_data, sizeof(*data));
+ data = memremap_cache(pa_data, sizeof(*data));
if (!data) {
ret = -ENOMEM;
goto out;
}
pa_data = data->next;
- iounmap(data);
+ memunmap(data);
}

out:
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index cc5ccc415cc0..7f087cb793fa 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -414,12 +414,10 @@ void *xlate_dev_mem_ptr(phys_addr_t phys)
if (page_is_ram(start >> PAGE_SHIFT))
return __va(phys);

- vaddr = ioremap_cache(start, PAGE_SIZE);
- /* Only add the offset on success and return NULL if the ioremap() failed: */
+ vaddr = memremap_cache(start, PAGE_SIZE);
if (vaddr)
- vaddr += offset;
-
- return vaddr;
+ return vaddr + offset;
+ return NULL;
}

void unxlate_dev_mem_ptr(phys_addr_t phys, void *addr)
@@ -427,7 +425,7 @@ void unxlate_dev_mem_ptr(phys_addr_t phys, void *addr)
if (page_is_ram(phys >> PAGE_SHIFT))
return;

- iounmap((void __iomem *)((unsigned long)addr & PAGE_MASK));
+ memunmap((void *)((unsigned long)addr & PAGE_MASK));
}

static pte_t bm_pte[PAGE_SIZE/sizeof(pte_t)] __page_aligned_bss;
diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index 87be10e8b57a..e601faf87cee 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -3,6 +3,7 @@ config ZONE_DMA

config XTENSA
def_bool y
+ select ARCH_HAS_MEMREMAP
select ARCH_WANT_FRAME_POINTERS
select ARCH_WANT_IPC_PARSE_VERSION
select ARCH_WANT_OPTIONAL_GPIOLIB
diff --git a/drivers/acpi/apei/einj.c b/drivers/acpi/apei/einj.c
index a095d4f858da..2ec9006cfb6c 100644
--- a/drivers/acpi/apei/einj.c
+++ b/drivers/acpi/apei/einj.c
@@ -318,7 +318,7 @@ static int __einj_error_trigger(u64 trigger_paddr, u32 type,
sizeof(*trigger_tab) - 1);
goto out;
}
- trigger_tab = ioremap_cache(trigger_paddr, sizeof(*trigger_tab));
+ trigger_tab = memremap_cache(trigger_paddr, sizeof(*trigger_tab));
if (!trigger_tab) {
pr_err(EINJ_PFX "Failed to map trigger table!\n");
goto out_rel_header;
@@ -346,8 +346,8 @@ static int __einj_error_trigger(u64 trigger_paddr, u32 type,
(unsigned long long)trigger_paddr + table_size - 1);
goto out_rel_header;
}
- iounmap(trigger_tab);
- trigger_tab = ioremap_cache(trigger_paddr, table_size);
+ memunmap(trigger_tab);
+ trigger_tab = memremap_cache(trigger_paddr, table_size);
if (!trigger_tab) {
pr_err(EINJ_PFX "Failed to map trigger table!\n");
goto out_rel_entry;
@@ -409,7 +409,7 @@ out_rel_header:
release_mem_region(trigger_paddr, sizeof(*trigger_tab));
out:
if (trigger_tab)
- iounmap(trigger_tab);
+ memunmap(trigger_tab);

return rc;
}
diff --git a/drivers/acpi/apei/erst.c b/drivers/acpi/apei/erst.c
index 3670bbab57a3..6b95066da51d 100644
--- a/drivers/acpi/apei/erst.c
+++ b/drivers/acpi/apei/erst.c
@@ -77,7 +77,7 @@ static struct acpi_table_erst *erst_tab;
static struct erst_erange {
u64 base;
u64 size;
- void __iomem *vaddr;
+ void *vaddr;
u32 attr;
} erst_erange;

@@ -1185,7 +1185,7 @@ static int __init erst_init(void)
goto err_unmap_reg;
}
rc = -ENOMEM;
- erst_erange.vaddr = ioremap_cache(erst_erange.base,
+ erst_erange.vaddr = memremap_cache(erst_erange.base,
erst_erange.size);
if (!erst_erange.vaddr)
goto err_release_erange;
diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index eb1fed5bd516..98418fc330ae 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -406,6 +406,7 @@ config BLK_DEV_RAM_DAX

config BLK_DEV_PMEM
tristate "Persistent memory block device support"
+ depends on ARCH_HAS_MEMREMAP
help
Saying Y here will allow you to use a contiguous range of reserved
memory as one or more persistent block devices.
diff --git a/drivers/block/pmem.c b/drivers/block/pmem.c
index 095dfaadcaa5..b00b97314b57 100644
--- a/drivers/block/pmem.c
+++ b/drivers/block/pmem.c
@@ -23,6 +23,7 @@
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/slab.h>
+#include <linux/io.h>

#define PMEM_MINORS 16

@@ -143,7 +144,7 @@ static struct pmem_device *pmem_alloc(struct device *dev, struct resource *res)
* of the CPU caches in case of a crash.
*/
err = -ENOMEM;
- pmem->virt_addr = ioremap_wt(pmem->phys_addr, pmem->size);
+ pmem->virt_addr = memremap_wt(pmem->phys_addr, pmem->size);
if (!pmem->virt_addr)
goto out_release_region;

@@ -179,7 +180,7 @@ static struct pmem_device *pmem_alloc(struct device *dev, struct resource *res)
out_free_queue:
blk_cleanup_queue(pmem->pmem_queue);
out_unmap:
- iounmap(pmem->virt_addr);
+ memunmap(pmem->virt_addr);
out_release_region:
release_mem_region(pmem->phys_addr, pmem->size);
out_free_dev:
@@ -193,7 +194,7 @@ static void pmem_free(struct pmem_device *pmem)
del_gendisk(pmem->pmem_disk);
put_disk(pmem->pmem_disk);
blk_cleanup_queue(pmem->pmem_queue);
- iounmap(pmem->virt_addr);
+ memunmap(pmem->virt_addr);
release_mem_region(pmem->phys_addr, pmem->size);
kfree(pmem);
}
diff --git a/drivers/firmware/google/memconsole.c b/drivers/firmware/google/memconsole.c
index 2f569aaed4c7..877433dc8297 100644
--- a/drivers/firmware/google/memconsole.c
+++ b/drivers/firmware/google/memconsole.c
@@ -52,14 +52,14 @@ static ssize_t memconsole_read(struct file *filp, struct kobject *kobp,
char *memconsole;
ssize_t ret;

- memconsole = ioremap_cache(memconsole_baseaddr, memconsole_length);
+ memconsole = memremap_cache(memconsole_baseaddr, memconsole_length);
if (!memconsole) {
pr_err("memconsole: ioremap_cache failed\n");
return -ENOMEM;
}
ret = memory_read_from_buffer(buf, count, &pos, memconsole,
memconsole_length);
- iounmap(memconsole);
+ memunmap(memconsole);
return ret;
}

diff --git a/include/linux/device.h b/include/linux/device.h
index 6558af90c8fe..518f49c5d596 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -638,6 +638,11 @@ extern void devm_free_pages(struct device *dev, unsigned long addr);

void __iomem *devm_ioremap_resource(struct device *dev, struct resource *res);

+static inline void *devm_memremap_resource(struct device *dev, struct resource *res)
+{
+ return (void __force *) devm_ioremap_resource(dev, res);
+}
+
/* allows to add/remove a custom action to devres stack */
int devm_add_action(struct device *dev, void (*action)(void *), void *data);
void devm_remove_action(struct device *dev, void (*action)(void *), void *data);
diff --git a/include/linux/io.h b/include/linux/io.h
index 8789a114f37c..21dc5de483f6 100644
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -181,4 +181,8 @@ static inline int arch_phys_wc_index(int handle)
#endif
#endif

+extern void *memremap_cache(resource_size_t offset, size_t size);
+extern void *memremap_wt(resource_size_t offset, size_t size);
+extern void memunmap(void *addr);
+
#endif /* _LINUX_IO_H */
diff --git a/kernel/resource.c b/kernel/resource.c
index 90552aab5f2d..2f8aca09da52 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -23,7 +23,7 @@
#include <linux/pfn.h>
#include <linux/mm.h>
#include <linux/resource_ext.h>
-#include <asm/io.h>
+#include <linux/io.h>

struct resource ioport_resource = {
@@ -528,6 +528,45 @@ int region_is_ram(resource_size_t start, unsigned long size)
return ret;
}

+#ifdef CONFIG_ARCH_HAS_MEMREMAP
+/*
+ * 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.
+ */
+static bool memremap_valid(resource_size_t offset, size_t size)
+{
+ if (region_is_ram(offset, size) != 0) {
+ WARN_ONCE(1, "memremap attempted on ram %pa size: %zu\n",
+ &offset, size);
+ return false;
+ }
+ return true;
+}
+
+void *memremap_cache(resource_size_t offset, size_t size)
+{
+ if (!memremap_valid(offset, size))
+ return NULL;
+ return (void __force *) ioremap_cache(offset, size);
+}
+EXPORT_SYMBOL(memremap_cache);
+
+void *memremap_wt(resource_size_t offset, size_t size)
+{
+ if (!memremap_valid(offset, size))
+ return NULL;
+ return (void __force *) ioremap_wt(offset, size);
+}
+EXPORT_SYMBOL(memremap_wt);
+
+void memunmap(void *addr)
+{
+ iounmap((void __iomem __force *) addr);
+}
+EXPORT_SYMBOL(memunmap);
+#endif /* CONFIG_ARCH_HAS_MEMREMAP */
+
void __weak arch_remove_reservations(struct resource *avail)
{
}
diff --git a/lib/Kconfig b/lib/Kconfig
index 601965a948e8..bc7bc0278921 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -520,6 +520,9 @@ source "lib/fonts/Kconfig"
#

config ARCH_HAS_SG_CHAIN
- def_bool n
+ bool
+
+config ARCH_HAS_MEMREMAP
+ bool

endmenu

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