mm: remove devmap related functions and page table bits

Now that DAX and all other reference counts to ZONE_DEVICE pages are
managed normally there is no need for the special devmap PTE/PMD/PUD page
table bits.  So drop all references to these, freeing up a software
defined page table bit on architectures supporting it.

Link: https://lkml.kernel.org/r/6389398c32cc9daa3dfcaa9f79c7972525d310ce.1750323463.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Acked-by: Will Deacon <will@kernel.org> # arm64
Acked-by: David Hildenbrand <david@redhat.com>
Suggested-by: Chunyan Zhang <zhang.lyra@gmail.com>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: Björn Töpel <bjorn@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Deepak Gupta <debug@rivosinc.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Inki Dae <m.szyprowski@samsung.com>
Cc: John Groves <john@groves.net>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

3 files changed, 0 insertions, 39 deletions

diff --git a/arch/riscv/include/asm/pgtable-64.h b/arch/riscv/include/asm/pgtable-64.h
index 7de05db7d3bd..1018d2216901 100644
--- a/arch/riscv/include/asm/pgtable-64.h
+++ b/arch/riscv/include/asm/pgtable-64.h
@@ -397,24 +397,8 @@ static inline struct page *pgd_page(pgd_t pgd)
 p4d_t *p4d_offset(pgd_t *pgd, unsigned long address);
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-static inline int pte_devmap(pte_t pte);
 static inline pte_t pmd_pte(pmd_t pmd);
 static inline pte_t pud_pte(pud_t pud);
-
-static inline int pmd_devmap(pmd_t pmd)
-{
-	return pte_devmap(pmd_pte(pmd));
-}
-
-static inline int pud_devmap(pud_t pud)
-{
-	return pte_devmap(pud_pte(pud));
-}
-
-static inline int pgd_devmap(pgd_t pgd)
-{
-	return 0;
-}
 #endif
 
 #endif /* _ASM_RISCV_PGTABLE_64_H */
diff --git a/arch/riscv/include/asm/pgtable-bits.h b/arch/riscv/include/asm/pgtable-bits.h
index a8f5205cea54..179bd4afece4 100644
--- a/arch/riscv/include/asm/pgtable-bits.h
+++ b/arch/riscv/include/asm/pgtable-bits.h
@@ -19,7 +19,6 @@
 #define _PAGE_SOFT      (3 << 8)    /* Reserved for software */
 
 #define _PAGE_SPECIAL   (1 << 8)    /* RSW: 0x1 */
-#define _PAGE_DEVMAP    (1 << 9)    /* RSW, devmap */
 #define _PAGE_TABLE     _PAGE_PRESENT
 
 /*
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 5bd5aae60d53..91697fbf1f90 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -409,13 +409,6 @@ static inline int pte_special(pte_t pte)
 	return pte_val(pte) & _PAGE_SPECIAL;
 }
 
-#ifdef CONFIG_ARCH_HAS_PTE_DEVMAP
-static inline int pte_devmap(pte_t pte)
-{
-	return pte_val(pte) & _PAGE_DEVMAP;
-}
-#endif
-
 /* static inline pte_t pte_rdprotect(pte_t pte) */
 
 static inline pte_t pte_wrprotect(pte_t pte)
@@ -457,11 +450,6 @@ static inline pte_t pte_mkspecial(pte_t pte)
 	return __pte(pte_val(pte) | _PAGE_SPECIAL);
 }
 
-static inline pte_t pte_mkdevmap(pte_t pte)
-{
-	return __pte(pte_val(pte) | _PAGE_DEVMAP);
-}
-
 static inline pte_t pte_mkhuge(pte_t pte)
 {
 	return pte;
@@ -790,11 +778,6 @@ static inline pmd_t pmd_mkdirty(pmd_t pmd)
 	return pte_pmd(pte_mkdirty(pmd_pte(pmd)));
 }
 
-static inline pmd_t pmd_mkdevmap(pmd_t pmd)
-{
-	return pte_pmd(pte_mkdevmap(pmd_pte(pmd)));
-}
-
 #ifdef CONFIG_ARCH_SUPPORTS_PMD_PFNMAP
 static inline bool pmd_special(pmd_t pmd)
 {
@@ -946,11 +929,6 @@ static inline pud_t pud_mkhuge(pud_t pud)
 	return pud;
 }
 
-static inline pud_t pud_mkdevmap(pud_t pud)
-{
-	return pte_pud(pte_mkdevmap(pud_pte(pud)));
-}
-
 static inline int pudp_set_access_flags(struct vm_area_struct *vma,
 					unsigned long address, pud_t *pudp,
 					pud_t entry, int dirty)