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x86, pat: Add PAT reserve free to io_mapping* APIs 

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>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
hifive-unleashed-5.1
Venkatesh Pallipadi 2009-07-10 09:57:35 -07:00 committed by H. Peter Anvin
parent 9fd126bc74
commit 9e36fda0b3
3 changed files with 43 additions and 10 deletions
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9
arch/x86/include/asm/iomap.h
View File

@ -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 */

27
arch/x86/mm/iomap_32.c
View File

@ -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)
{

17
include/linux/io-mapping.h
View File

@ -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);
}