linux-stable/include/linux/pfn_t.h
Dan Williams 785a3fab4a mm, dax: introduce pfn_t_special()
In support of removing the VM_MIXEDMAP indication from DAX VMAs,
introduce pfn_t_special() for drivers to indicate that _PAGE_SPECIAL
should be used for DAX ptes. This also helps identify drivers like
dccssblk that only want to use DAX in a read-only fashion without
get_user_pages() support.

Ideally we could delete axonram and dcssblk DAX support, but if we need
to keep it better make it explicit that axonram and dcssblk only support
a sub-set of DAX due to missing _PAGE_DEVMAP support.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-01-19 16:50:53 -08:00

136 lines
3.2 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_PFN_T_H_
#define _LINUX_PFN_T_H_
#include <linux/mm.h>
/*
* PFN_FLAGS_MASK - mask of all the possible valid pfn_t flags
* PFN_SG_CHAIN - pfn is a pointer to the next scatterlist entry
* PFN_SG_LAST - pfn references a page and is the last scatterlist entry
* 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 (((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))
#define PFN_SPECIAL (1ULL << (BITS_PER_LONG_LONG - 5))
#define PFN_FLAGS_TRACE \
{ PFN_SPECIAL, "SPECIAL" }, \
{ PFN_SG_CHAIN, "SG_CHAIN" }, \
{ PFN_SG_LAST, "SG_LAST" }, \
{ PFN_DEV, "DEV" }, \
{ PFN_MAP, "MAP" }
static inline pfn_t __pfn_to_pfn_t(unsigned long pfn, u64 flags)
{
pfn_t pfn_t = { .val = pfn | (flags & PFN_FLAGS_MASK), };
return pfn_t;
}
/* a default pfn to pfn_t conversion assumes that @pfn is pfn_valid() */
static inline pfn_t pfn_to_pfn_t(unsigned long pfn)
{
return __pfn_to_pfn_t(pfn, 0);
}
static inline pfn_t phys_to_pfn_t(phys_addr_t addr, u64 flags)
{
return __pfn_to_pfn_t(addr >> PAGE_SHIFT, flags);
}
static inline bool pfn_t_has_page(pfn_t pfn)
{
return (pfn.val & PFN_MAP) == PFN_MAP || (pfn.val & PFN_DEV) == 0;
}
static inline unsigned long pfn_t_to_pfn(pfn_t pfn)
{
return pfn.val & ~PFN_FLAGS_MASK;
}
static inline struct page *pfn_t_to_page(pfn_t pfn)
{
if (pfn_t_has_page(pfn))
return pfn_to_page(pfn_t_to_pfn(pfn));
return NULL;
}
static inline phys_addr_t pfn_t_to_phys(pfn_t pfn)
{
return PFN_PHYS(pfn_t_to_pfn(pfn));
}
static inline void *pfn_t_to_virt(pfn_t pfn)
{
if (pfn_t_has_page(pfn))
return __va(pfn_t_to_phys(pfn));
return NULL;
}
static inline pfn_t page_to_pfn_t(struct page *page)
{
return pfn_to_pfn_t(page_to_pfn(page));
}
static inline int pfn_t_valid(pfn_t pfn)
{
return pfn_valid(pfn_t_to_pfn(pfn));
}
#ifdef CONFIG_MMU
static inline pte_t pfn_t_pte(pfn_t pfn, pgprot_t pgprot)
{
return pfn_pte(pfn_t_to_pfn(pfn), pgprot);
}
#endif
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static inline pmd_t pfn_t_pmd(pfn_t pfn, pgprot_t pgprot)
{
return pfn_pmd(pfn_t_to_pfn(pfn), pgprot);
}
#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
static inline pud_t pfn_t_pud(pfn_t pfn, pgprot_t pgprot)
{
return pfn_pud(pfn_t_to_pfn(pfn), pgprot);
}
#endif
#endif
#ifdef __HAVE_ARCH_PTE_DEVMAP
static inline bool pfn_t_devmap(pfn_t pfn)
{
const u64 flags = PFN_DEV|PFN_MAP;
return (pfn.val & flags) == flags;
}
#else
static inline bool pfn_t_devmap(pfn_t pfn)
{
return false;
}
pte_t pte_mkdevmap(pte_t pte);
pmd_t pmd_mkdevmap(pmd_t pmd);
#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \
defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
pud_t pud_mkdevmap(pud_t pud);
#endif
#endif /* __HAVE_ARCH_PTE_DEVMAP */
#ifdef __HAVE_ARCH_PTE_SPECIAL
static inline bool pfn_t_special(pfn_t pfn)
{
return (pfn.val & PFN_SPECIAL) == PFN_SPECIAL;
}
#else
static inline bool pfn_t_special(pfn_t pfn)
{
return false;
}
#endif /* __HAVE_ARCH_PTE_SPECIAL */
#endif /* _LINUX_PFN_T_H_ */