[PATCH 3/3] mm: introduce ARCH_HAS_PTE_DEVMAP

From: Robin Murphy
Date: Fri Apr 12 2019 - 14:57:31 EST

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with the long-out-of-date comment can lead to the impression than an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.murphy@xxxxxxx>
---
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