1 files changed, 131 insertions, 0 deletions
diff --git a/include/linux/pfn_t.h b/include/linux/pfn_t.h
new file mode 100644
index 000000000..2d9148221
--- /dev/null
+++ b/include/linux/pfn_t.h
@@ -0,0 +1,131 @@
+/* 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
+ * PFN_SPECIAL - for CONFIG_FS_DAX_LIMITED builds to allow XIP, but not
+ *		 get_user_pages
+ */
+#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 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 CONFIG_ARCH_HAS_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 /* CONFIG_ARCH_HAS_PTE_DEVMAP */
+
+#ifdef CONFIG_ARCH_HAS_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 /* CONFIG_ARCH_HAS_PTE_SPECIAL */
+#endif /* _LINUX_PFN_T_H_ */