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Commit 9e36fda0 authored by Venkatesh Pallipadi's avatar Venkatesh Pallipadi Committed by H. Peter Anvin
Browse files

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: default avatarVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent 9fd126bc

arch/x86/include/asm/iomap.h

+6 −3
Original line number Diff line number Diff line
@@ -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 */

arch/x86/mm/iomap_32.c

+25 −2
Original line number Diff line number Diff line
@@ -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)

{

include/linux/io-mapping.h

+12 −5
Original line number Diff line number Diff line
@@ -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);

}