ARCH_HAS_ZONE_DEVICE is somewhat meaningless in itself, and combined
with the long-out-of-date comment can lead to the impression than an
architecture may just enable it (since __add_pages() now "comprehends
device memory" for itself) and expect things to work.

In practice, however, ZONE_DEVICE users have little chance of
functioning correctly without __HAVE_ARCH_PTE_DEVMAP, so let's clean
that up the same way as ARCH_HAS_PTE_SPECIAL and make it the proper
dependency so the real situation is clearer.

Signed-off-by: Robin Murphy <robin.mur...@arm.com>
---
 arch/powerpc/Kconfig                         | 2 +-
 arch/powerpc/include/asm/book3s/64/pgtable.h | 1 -
 arch/x86/Kconfig                             | 2 +-
 arch/x86/include/asm/pgtable.h               | 4 ++--
 arch/x86/include/asm/pgtable_types.h         | 1 -
 include/linux/mm.h                           | 4 ++--
 include/linux/pfn_t.h                        | 4 ++--
 mm/Kconfig                                   | 5 ++---
 mm/gup.c                                     | 2 +-
 9 files changed, 11 insertions(+), 14 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 5e3d0853c31d..77e1993bba80 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -135,6 +135,7 @@ config PPC
        select ARCH_HAS_MMIOWB                  if PPC64
        select ARCH_HAS_PHYS_TO_DMA
        select ARCH_HAS_PMEM_API                if PPC64
+       select ARCH_HAS_PTE_DEVMAP              if PPC_BOOK3S_64
        select ARCH_HAS_PTE_SPECIAL
        select ARCH_HAS_MEMBARRIER_CALLBACKS
        select ARCH_HAS_SCALED_CPUTIME          if VIRT_CPU_ACCOUNTING_NATIVE 
&& PPC64
@@ -142,7 +143,6 @@ config PPC
        select ARCH_HAS_TICK_BROADCAST          if GENERIC_CLOCKEVENTS_BROADCAST
        select ARCH_HAS_UACCESS_FLUSHCACHE      if PPC64
        select ARCH_HAS_UBSAN_SANITIZE_ALL
-       select ARCH_HAS_ZONE_DEVICE             if PPC_BOOK3S_64
        select ARCH_HAVE_NMI_SAFE_CMPXCHG
        select ARCH_MIGHT_HAVE_PC_PARPORT
        select ARCH_MIGHT_HAVE_PC_SERIO
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h 
b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 581f91be9dd4..02c22ac8f387 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -90,7 +90,6 @@
 #define _PAGE_SOFT_DIRTY       _RPAGE_SW3 /* software: software dirty tracking 
*/
 #define _PAGE_SPECIAL          _RPAGE_SW2 /* software: special page */
 #define _PAGE_DEVMAP           _RPAGE_SW1 /* software: ZONE_DEVICE page */
-#define __HAVE_ARCH_PTE_DEVMAP
 
 /*
  * Drivers request for cache inhibited pte mapping using _PAGE_NO_CACHE
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 5ad92419be19..ffd50f27f395 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -60,6 +60,7 @@ config X86
        select ARCH_HAS_KCOV                    if X86_64
        select ARCH_HAS_MEMBARRIER_SYNC_CORE
        select ARCH_HAS_PMEM_API                if X86_64
+       select ARCH_HAS_PTE_DEVMAP              if X86_64
        select ARCH_HAS_PTE_SPECIAL
        select ARCH_HAS_REFCOUNT
        select ARCH_HAS_UACCESS_FLUSHCACHE      if X86_64
@@ -69,7 +70,6 @@ config X86
        select ARCH_HAS_STRICT_MODULE_RWX
        select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
        select ARCH_HAS_UBSAN_SANITIZE_ALL
-       select ARCH_HAS_ZONE_DEVICE             if X86_64
        select ARCH_HAVE_NMI_SAFE_CMPXCHG
        select ARCH_MIGHT_HAVE_ACPI_PDC         if ACPI
        select ARCH_MIGHT_HAVE_PC_PARPORT
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 2779ace16d23..89a1f6fd48bf 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -254,7 +254,7 @@ static inline int has_transparent_hugepage(void)
        return boot_cpu_has(X86_FEATURE_PSE);
 }
 
-#ifdef __HAVE_ARCH_PTE_DEVMAP
+#ifdef CONFIG_ARCH_HAS_PTE_DEVMAP
 static inline int pmd_devmap(pmd_t pmd)
 {
        return !!(pmd_val(pmd) & _PAGE_DEVMAP);
@@ -715,7 +715,7 @@ static inline int pte_present(pte_t a)
        return pte_flags(a) & (_PAGE_PRESENT | _PAGE_PROTNONE);
 }
 
-#ifdef __HAVE_ARCH_PTE_DEVMAP
+#ifdef CONFIG_ARCH_HAS_PTE_DEVMAP
 static inline int pte_devmap(pte_t a)
 {
        return (pte_flags(a) & _PAGE_DEVMAP) == _PAGE_DEVMAP;
diff --git a/arch/x86/include/asm/pgtable_types.h 
b/arch/x86/include/asm/pgtable_types.h
index d6ff0bbdb394..b5e49e6bac63 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -103,7 +103,6 @@
 #if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
 #define _PAGE_NX       (_AT(pteval_t, 1) << _PAGE_BIT_NX)
 #define _PAGE_DEVMAP   (_AT(u64, 1) << _PAGE_BIT_DEVMAP)
-#define __HAVE_ARCH_PTE_DEVMAP
 #else
 #define _PAGE_NX       (_AT(pteval_t, 0))
 #define _PAGE_DEVMAP   (_AT(pteval_t, 0))
diff --git a/include/linux/mm.h b/include/linux/mm.h
index d76dfb7ac617..fe05c94f23e9 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -504,7 +504,7 @@ struct inode;
 #define page_private(page)             ((page)->private)
 #define set_page_private(page, v)      ((page)->private = (v))
 
-#if !defined(__HAVE_ARCH_PTE_DEVMAP) || !defined(CONFIG_TRANSPARENT_HUGEPAGE)
+#if !defined(CONFIG_ARCH_HAS_PTE_DEVMAP) || 
!defined(CONFIG_TRANSPARENT_HUGEPAGE)
 static inline int pmd_devmap(pmd_t pmd)
 {
        return 0;
@@ -1698,7 +1698,7 @@ static inline void sync_mm_rss(struct mm_struct *mm)
 }
 #endif
 
-#ifndef __HAVE_ARCH_PTE_DEVMAP
+#ifndef CONFIG_ARCH_HAS_PTE_DEVMAP
 static inline int pte_devmap(pte_t pte)
 {
        return 0;
diff --git a/include/linux/pfn_t.h b/include/linux/pfn_t.h
index 7bb77850c65a..de8bc66b10a4 100644
--- a/include/linux/pfn_t.h
+++ b/include/linux/pfn_t.h
@@ -104,7 +104,7 @@ static inline pud_t pfn_t_pud(pfn_t pfn, pgprot_t pgprot)
 #endif
 #endif
 
-#ifdef __HAVE_ARCH_PTE_DEVMAP
+#ifdef CONFIG_ARCH_HAS_PTE_DEVMAP
 static inline bool pfn_t_devmap(pfn_t pfn)
 {
        const u64 flags = PFN_DEV|PFN_MAP;
@@ -122,7 +122,7 @@ pmd_t pmd_mkdevmap(pmd_t pmd);
        defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
 pud_t pud_mkdevmap(pud_t pud);
 #endif
-#endif /* __HAVE_ARCH_PTE_DEVMAP */
+#endif /* CONFIG_ARCH_HAS_PTE_DEVMAP */
 
 #ifdef CONFIG_ARCH_HAS_PTE_SPECIAL
 static inline bool pfn_t_special(pfn_t pfn)
diff --git a/mm/Kconfig b/mm/Kconfig
index 25c71eb8a7db..fcb7ab08e294 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -655,8 +655,7 @@ config IDLE_PAGE_TRACKING
          See Documentation/admin-guide/mm/idle_page_tracking.rst for
          more details.
 
-# arch_add_memory() comprehends device memory
-config ARCH_HAS_ZONE_DEVICE
+config ARCH_HAS_PTE_DEVMAP
        bool
 
 config ZONE_DEVICE
@@ -664,7 +663,7 @@ config ZONE_DEVICE
        depends on MEMORY_HOTPLUG
        depends on MEMORY_HOTREMOVE
        depends on SPARSEMEM_VMEMMAP
-       depends on ARCH_HAS_ZONE_DEVICE
+       depends on ARCH_HAS_PTE_DEVMAP
        select XARRAY_MULTI
 
        help
diff --git a/mm/gup.c b/mm/gup.c
index f84e22685aaa..72a5c7d1e1a7 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1623,7 +1623,7 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, 
unsigned long end,
 }
 #endif /* CONFIG_ARCH_HAS_PTE_SPECIAL */
 
-#if defined(__HAVE_ARCH_PTE_DEVMAP) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
+#if defined(CONFIG_ARCH_HAS_PTE_DEVMAP) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
 static int __gup_device_huge(unsigned long pfn, unsigned long addr,
                unsigned long end, struct page **pages, int *nr)
 {
-- 
2.21.0.dirty

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