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Subject[PATCH 04/10] x86, PAT: Add PAT reserve free to io_mapping* APIs
Date
io_mapping_* interfaces were added, mainly for graphics drivers.
Make this interface go through the PAT reserve/free, instead of
hardcoding WC mapping. This makes sure that there are no
aliases due to unconditional WC setting.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
---
arch/x86/include/asm/iomap.h | 9 ++++++---
arch/x86/mm/iomap_32.c | 27 +++++++++++++++++++++++++--
include/linux/io-mapping.h | 17 ++++++++++++-----
3 files changed, 43 insertions(+), 10 deletions(-)

diff --git a/arch/x86/include/asm/iomap.h b/arch/x86/include/asm/iomap.h
index 0e9fe1d..f35eb45 100644
--- a/arch/x86/include/asm/iomap.h
+++ b/arch/x86/include/asm/iomap.h
@@ -26,13 +26,16 @@
#include <asm/pgtable.h>
#include <asm/tlbflush.h>

-int
-is_io_mapping_possible(resource_size_t base, unsigned long size);
-
void *
iomap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot);

void
iounmap_atomic(void *kvaddr, enum km_type type);

+int
+iomap_create_wc(resource_size_t base, unsigned long size, pgprot_t *prot);
+
+void
+iomap_free(resource_size_t base, unsigned long size);
+
#endif /* _ASM_X86_IOMAP_H */
diff --git a/arch/x86/mm/iomap_32.c b/arch/x86/mm/iomap_32.c
index fe6f84c..84e236c 100644
--- a/arch/x86/mm/iomap_32.c
+++ b/arch/x86/mm/iomap_32.c
@@ -21,7 +21,7 @@
#include <linux/module.h>
#include <linux/highmem.h>

-int is_io_mapping_possible(resource_size_t base, unsigned long size)
+static int is_io_mapping_possible(resource_size_t base, unsigned long size)
{
#if !defined(CONFIG_X86_PAE) && defined(CONFIG_PHYS_ADDR_T_64BIT)
/* There is no way to map greater than 1 << 32 address without PAE */
@@ -30,7 +30,30 @@ int is_io_mapping_possible(resource_size_t base, unsigned long size)
#endif
return 1;
}
-EXPORT_SYMBOL_GPL(is_io_mapping_possible);
+
+int iomap_create_wc(resource_size_t base, unsigned long size, pgprot_t *prot)
+{
+ unsigned long flag = _PAGE_CACHE_WC;
+ int ret;
+
+ if (!is_io_mapping_possible(base, size))
+ return -EINVAL;
+
+ ret = io_reserve_memtype(base, base + size, &flag);
+ if (ret)
+ return ret;
+
+ *prot = __pgprot(__PAGE_KERNEL | flag);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(iomap_create_wc);
+
+void
+iomap_free(resource_size_t base, unsigned long size)
+{
+ io_free_memtype(base, base + size);
+}
+EXPORT_SYMBOL_GPL(iomap_free);

void *kmap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot)
{
diff --git a/include/linux/io-mapping.h b/include/linux/io-mapping.h
index 0adb0f9..97eb928 100644
--- a/include/linux/io-mapping.h
+++ b/include/linux/io-mapping.h
@@ -49,23 +49,30 @@ static inline struct io_mapping *
io_mapping_create_wc(resource_size_t base, unsigned long size)
{
struct io_mapping *iomap;
-
- if (!is_io_mapping_possible(base, size))
- return NULL;
+ pgprot_t prot;

iomap = kmalloc(sizeof(*iomap), GFP_KERNEL);
if (!iomap)
- return NULL;
+ goto out_err;
+
+ if (iomap_create_wc(base, size, &prot))
+ goto out_free;

iomap->base = base;
iomap->size = size;
- iomap->prot = pgprot_writecombine(__pgprot(__PAGE_KERNEL));
+ iomap->prot = prot;
return iomap;
+
+out_free:
+ kfree(iomap);
+out_err:
+ return NULL;
}

static inline void
io_mapping_free(struct io_mapping *mapping)
{
+ iomap_free(mapping->base, mapping->size);
kfree(mapping);
}

--
1.6.0.6


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