Commit db78c222 authored by Dan Williams's avatar Dan Williams Committed by Linus Torvalds
Browse files

mm: fix pfn_t vs highmem 

The pfn_t type uses an unsigned long to store a pfn + flags value.  On a
64-bit platform the upper 12 bits of an unsigned long are never used for
storing the value of a pfn.  However, this is not true on highmem
platforms, all 32-bits of a pfn value are used to address a 44-bit
physical address space.  A pfn_t needs to store a 64-bit value.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=112211


Fixes: 01c8f1c4 ("mm, dax, gpu: convert vm_insert_mixed to pfn_t")
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
Reported-by: default avatarStuart Foster <smf.linux@ntlworld.com>
Reported-by: default avatarJulian Margetson <runaway@candw.ms>
Tested-by: default avatarJulian Margetson <runaway@candw.ms>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4a389810

include/linux/pfn.h

+1 −1
Original line number Diff line number Diff line
@@ -10,7 +10,7 @@ 
 * backing is indicated by flags in the high bits of the value.

 */

typedef struct {

	unsigned long val;

	u64 val;

} pfn_t;

#endif

include/linux/pfn_t.h

+9 −10
Original line number Diff line number Diff line
@@ -9,14 +9,13 @@ 
 * PFN_DEV - pfn is not covered by system memmap by default

 * PFN_MAP - pfn has a dynamic page mapping established by a device driver

 */

#define PFN_FLAGS_MASK (((unsigned long) ~PAGE_MASK) \

		<< (BITS_PER_LONG - PAGE_SHIFT))

#define PFN_SG_CHAIN (1UL << (BITS_PER_LONG - 1))

#define PFN_SG_LAST (1UL << (BITS_PER_LONG - 2))

#define PFN_DEV (1UL << (BITS_PER_LONG - 3))

#define PFN_MAP (1UL << (BITS_PER_LONG - 4))



static inline pfn_t __pfn_to_pfn_t(unsigned long pfn, unsigned long flags)

#define PFN_FLAGS_MASK (((u64) ~PAGE_MASK) << (BITS_PER_LONG_LONG - PAGE_SHIFT))

#define PFN_SG_CHAIN (1ULL << (BITS_PER_LONG_LONG - 1))

#define PFN_SG_LAST (1ULL << (BITS_PER_LONG_LONG - 2))

#define PFN_DEV (1ULL << (BITS_PER_LONG_LONG - 3))

#define PFN_MAP (1ULL << (BITS_PER_LONG_LONG - 4))



static inline pfn_t __pfn_to_pfn_t(unsigned long pfn, u64 flags)

{

	pfn_t pfn_t = { .val = pfn | (flags & PFN_FLAGS_MASK), };
@@ -29,7 +28,7 @@ static inline pfn_t pfn_to_pfn_t(unsigned long pfn) 
	return __pfn_to_pfn_t(pfn, 0);

}



extern pfn_t phys_to_pfn_t(phys_addr_t addr, unsigned long flags);

extern pfn_t phys_to_pfn_t(phys_addr_t addr, u64 flags);



static inline bool pfn_t_has_page(pfn_t pfn)

{
@@ -87,7 +86,7 @@ static inline pmd_t pfn_t_pmd(pfn_t pfn, pgprot_t pgprot) 
#ifdef __HAVE_ARCH_PTE_DEVMAP

static inline bool pfn_t_devmap(pfn_t pfn)

{

	const unsigned long flags = PFN_DEV|PFN_MAP;

	const u64 flags = PFN_DEV|PFN_MAP;



	return (pfn.val & flags) == flags;

}

kernel/memremap.c

+1 −1
Original line number Diff line number Diff line
@@ -150,7 +150,7 @@ void devm_memunmap(struct device *dev, void *addr) 
}

EXPORT_SYMBOL(devm_memunmap);



pfn_t phys_to_pfn_t(phys_addr_t addr, unsigned long flags)

pfn_t phys_to_pfn_t(phys_addr_t addr, u64 flags)

{

	return __pfn_to_pfn_t(addr >> PAGE_SHIFT, flags);

}

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