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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: 01c8f1c44b ("mm, dax, gpu: convert vm_insert_mixed to pfn_t")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Stuart Foster <smf.linux@ntlworld.com>
Reported-by: Julian Margetson <runaway@candw.ms>
Tested-by: Julian Margetson <runaway@candw.ms>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Dan Williams 2016-02-11 16:13:17 -08:00 committed by Linus Torvalds
parent 4a389810bc
commit db78c22230
3 changed files with 10 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/pfn.h
View File

@ -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

17
include/linux/pfn_t.h
View File

@ -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))
#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, unsigned long flags)
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;
}

2
kernel/memremap.c
View File

@ -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);
}