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![Dan Williams](/assets/img/avatar_default.png)
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>
23 lines
627 B
C
23 lines
627 B
C
#ifndef _LINUX_PFN_H_
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#define _LINUX_PFN_H_
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#ifndef __ASSEMBLY__
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#include <linux/types.h>
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/*
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* pfn_t: encapsulates a page-frame number that is optionally backed
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* by memmap (struct page). Whether a pfn_t has a 'struct page'
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* backing is indicated by flags in the high bits of the value.
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*/
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typedef struct {
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u64 val;
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} pfn_t;
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#endif
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#define PFN_ALIGN(x) (((unsigned long)(x) + (PAGE_SIZE - 1)) & PAGE_MASK)
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#define PFN_UP(x) (((x) + PAGE_SIZE-1) >> PAGE_SHIFT)
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#define PFN_DOWN(x) ((x) >> PAGE_SHIFT)
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#define PFN_PHYS(x) ((phys_addr_t)(x) << PAGE_SHIFT)
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#define PHYS_PFN(x) ((unsigned long)((x) >> PAGE_SHIFT))
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#endif
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