785a3fab4a
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>
136 lines
3.2 KiB
C
136 lines
3.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_PFN_T_H_
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#define _LINUX_PFN_T_H_
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#include <linux/mm.h>
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/*
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* PFN_FLAGS_MASK - mask of all the possible valid pfn_t flags
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* PFN_SG_CHAIN - pfn is a pointer to the next scatterlist entry
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* PFN_SG_LAST - pfn references a page and is the last scatterlist entry
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* PFN_DEV - pfn is not covered by system memmap by default
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* PFN_MAP - pfn has a dynamic page mapping established by a device driver
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*/
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#define PFN_FLAGS_MASK (((u64) ~PAGE_MASK) << (BITS_PER_LONG_LONG - PAGE_SHIFT))
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#define PFN_SG_CHAIN (1ULL << (BITS_PER_LONG_LONG - 1))
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#define PFN_SG_LAST (1ULL << (BITS_PER_LONG_LONG - 2))
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#define PFN_DEV (1ULL << (BITS_PER_LONG_LONG - 3))
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#define PFN_MAP (1ULL << (BITS_PER_LONG_LONG - 4))
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#define PFN_SPECIAL (1ULL << (BITS_PER_LONG_LONG - 5))
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#define PFN_FLAGS_TRACE \
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{ PFN_SPECIAL, "SPECIAL" }, \
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{ PFN_SG_CHAIN, "SG_CHAIN" }, \
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{ PFN_SG_LAST, "SG_LAST" }, \
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{ PFN_DEV, "DEV" }, \
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{ PFN_MAP, "MAP" }
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static inline pfn_t __pfn_to_pfn_t(unsigned long pfn, u64 flags)
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{
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pfn_t pfn_t = { .val = pfn | (flags & PFN_FLAGS_MASK), };
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return pfn_t;
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}
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/* a default pfn to pfn_t conversion assumes that @pfn is pfn_valid() */
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static inline pfn_t pfn_to_pfn_t(unsigned long pfn)
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{
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return __pfn_to_pfn_t(pfn, 0);
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}
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static inline pfn_t phys_to_pfn_t(phys_addr_t addr, u64 flags)
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{
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return __pfn_to_pfn_t(addr >> PAGE_SHIFT, flags);
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}
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static inline bool pfn_t_has_page(pfn_t pfn)
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{
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return (pfn.val & PFN_MAP) == PFN_MAP || (pfn.val & PFN_DEV) == 0;
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}
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static inline unsigned long pfn_t_to_pfn(pfn_t pfn)
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{
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return pfn.val & ~PFN_FLAGS_MASK;
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}
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static inline struct page *pfn_t_to_page(pfn_t pfn)
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{
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if (pfn_t_has_page(pfn))
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return pfn_to_page(pfn_t_to_pfn(pfn));
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return NULL;
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}
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static inline phys_addr_t pfn_t_to_phys(pfn_t pfn)
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{
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return PFN_PHYS(pfn_t_to_pfn(pfn));
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}
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static inline void *pfn_t_to_virt(pfn_t pfn)
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{
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if (pfn_t_has_page(pfn))
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return __va(pfn_t_to_phys(pfn));
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return NULL;
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}
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static inline pfn_t page_to_pfn_t(struct page *page)
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{
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return pfn_to_pfn_t(page_to_pfn(page));
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}
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static inline int pfn_t_valid(pfn_t pfn)
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{
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return pfn_valid(pfn_t_to_pfn(pfn));
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}
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#ifdef CONFIG_MMU
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static inline pte_t pfn_t_pte(pfn_t pfn, pgprot_t pgprot)
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{
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return pfn_pte(pfn_t_to_pfn(pfn), pgprot);
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}
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#endif
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#ifdef CONFIG_TRANSPARENT_HUGEPAGE
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static inline pmd_t pfn_t_pmd(pfn_t pfn, pgprot_t pgprot)
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{
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return pfn_pmd(pfn_t_to_pfn(pfn), pgprot);
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}
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#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
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static inline pud_t pfn_t_pud(pfn_t pfn, pgprot_t pgprot)
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{
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return pfn_pud(pfn_t_to_pfn(pfn), pgprot);
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}
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#endif
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#endif
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#ifdef __HAVE_ARCH_PTE_DEVMAP
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static inline bool pfn_t_devmap(pfn_t pfn)
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{
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const u64 flags = PFN_DEV|PFN_MAP;
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return (pfn.val & flags) == flags;
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}
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#else
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static inline bool pfn_t_devmap(pfn_t pfn)
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{
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return false;
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}
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pte_t pte_mkdevmap(pte_t pte);
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pmd_t pmd_mkdevmap(pmd_t pmd);
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#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \
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defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
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pud_t pud_mkdevmap(pud_t pud);
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#endif
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#endif /* __HAVE_ARCH_PTE_DEVMAP */
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#ifdef __HAVE_ARCH_PTE_SPECIAL
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static inline bool pfn_t_special(pfn_t pfn)
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{
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return (pfn.val & PFN_SPECIAL) == PFN_SPECIAL;
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}
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#else
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static inline bool pfn_t_special(pfn_t pfn)
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{
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return false;
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}
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#endif /* __HAVE_ARCH_PTE_SPECIAL */
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#endif /* _LINUX_PFN_T_H_ */
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