mm: introduce ARCH_HAS_PTE_SPECIAL

Currently the PTE special supports is turned on in per architecture
header files.  Most of the time, it is defined in
arch/*/include/asm/pgtable.h depending or not on some other per
architecture static definition.

This patch introduce a new configuration variable to manage this
directly in the Kconfig files.  It would later replace
__HAVE_ARCH_PTE_SPECIAL.

Here notes for some architecture where the definition of
__HAVE_ARCH_PTE_SPECIAL is not obvious:

arm
 __HAVE_ARCH_PTE_SPECIAL which is currently defined in
arch/arm/include/asm/pgtable-3level.h which is included by
arch/arm/include/asm/pgtable.h when CONFIG_ARM_LPAE is set.
So select ARCH_HAS_PTE_SPECIAL if ARM_LPAE.

powerpc
__HAVE_ARCH_PTE_SPECIAL is defined in 2 files:
 - arch/powerpc/include/asm/book3s/64/pgtable.h
 - arch/powerpc/include/asm/pte-common.h
The first one is included if (PPC_BOOK3S & PPC64) while the second is
included in all the other cases.
So select ARCH_HAS_PTE_SPECIAL all the time.

sparc:
__HAVE_ARCH_PTE_SPECIAL is defined if defined(__sparc__) &&
defined(__arch64__) which are defined through the compiler in
sparc/Makefile if !SPARC32 which I assume to be if SPARC64.
So select ARCH_HAS_PTE_SPECIAL if SPARC64

There is no functional change introduced by this patch.

Link: http://lkml.kernel.org/r/1523433816-14460-2-git-send-email-ldufour@linux.vnet.ibm.com
Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Suggested-by: Jerome Glisse <jglisse@redhat.com>
Reviewed-by: Jerome Glisse <jglisse@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Albert Ou <albert@sifive.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Christophe LEROY <christophe.leroy@c-s.fr>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/features/vm/pte_special/arch-support.txt

@@ -1,6 +1,6 @@
 #
 # Feature name:          pte_special
-#         Kconfig:       __HAVE_ARCH_PTE_SPECIAL
+#         Kconfig:       ARCH_HAS_PTE_SPECIAL
 #         description:   arch supports the pte_special()/pte_mkspecial() VM APIs
 #
     -----------------------

arch/arc/Kconfig

@@ -48,6 +48,7 @@ config ARC
 	select HAVE_GENERIC_DMA_COHERENT
 	select HAVE_KERNEL_GZIP
 	select HAVE_KERNEL_LZMA
+	select ARCH_HAS_PTE_SPECIAL
 
 config MIGHT_HAVE_PCI
 	bool

arch/arc/include/asm/pgtable.h

@@ -320,8 +320,6 @@ PTE_BIT_FUNC(mkexec,	|= (_PAGE_EXECUTE));
 PTE_BIT_FUNC(mkspecial,	|= (_PAGE_SPECIAL));
 PTE_BIT_FUNC(mkhuge,	|= (_PAGE_HW_SZ));
 
-#define __HAVE_ARCH_PTE_SPECIAL
-
 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 {
 	return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot));

arch/arm/Kconfig

@@ -8,6 +8,7 @@ config ARM
 	select ARCH_HAS_DEVMEM_IS_ALLOWED
 	select ARCH_HAS_ELF_RANDOMIZE
 	select ARCH_HAS_FORTIFY_SOURCE
+	select ARCH_HAS_PTE_SPECIAL if ARM_LPAE
 	select ARCH_HAS_SET_MEMORY
 	select ARCH_HAS_PHYS_TO_DMA
 	select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL

arch/arm/include/asm/pgtable-3level.h

@@ -219,7 +219,6 @@ static inline pte_t pte_mkspecial(pte_t pte)
 	pte_val(pte) |= L_PTE_SPECIAL;
 	return pte;
 }
-#define	__HAVE_ARCH_PTE_SPECIAL
 
 #define pmd_write(pmd)		(pmd_isclear((pmd), L_PMD_SECT_RDONLY))
 #define pmd_dirty(pmd)		(pmd_isset((pmd), L_PMD_SECT_DIRTY))

arch/arm64/Kconfig

@@ -17,6 +17,7 @@ config ARM64
 	select ARCH_HAS_GIGANTIC_PAGE if (MEMORY_ISOLATION && COMPACTION) || CMA
 	select ARCH_HAS_KCOV
 	select ARCH_HAS_MEMBARRIER_SYNC_CORE
+	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_SET_MEMORY
 	select ARCH_HAS_SG_CHAIN
 	select ARCH_HAS_STRICT_KERNEL_RWX

arch/arm64/include/asm/pgtable.h

@@ -306,8 +306,6 @@ static inline int pte_same(pte_t pte_a, pte_t pte_b)
 #define HPAGE_MASK		(~(HPAGE_SIZE - 1))
 #define HUGETLB_PAGE_ORDER	(HPAGE_SHIFT - PAGE_SHIFT)
 
-#define __HAVE_ARCH_PTE_SPECIAL
-
 static inline pte_t pgd_pte(pgd_t pgd)
 {
 	return __pte(pgd_val(pgd));

arch/powerpc/Kconfig

@@ -135,6 +135,7 @@ config PPC
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_HAS_PHYS_TO_DMA
 	select ARCH_HAS_PMEM_API                if PPC64
+	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_MEMBARRIER_CALLBACKS
 	select ARCH_HAS_SCALED_CPUTIME		if VIRT_CPU_ACCOUNTING_NATIVE
 	select ARCH_HAS_SG_CHAIN

arch/powerpc/include/asm/book3s/64/pgtable.h

@@ -335,9 +335,6 @@ extern unsigned long pci_io_base;
 /* Advertise special mapping type for AGP */
 #define HAVE_PAGE_AGP
 
-/* Advertise support for _PAGE_SPECIAL */
-#define __HAVE_ARCH_PTE_SPECIAL
-
 #ifndef __ASSEMBLY__
 
 /*

arch/powerpc/include/asm/pte-common.h

@@ -208,9 +208,6 @@ static inline bool pte_user(pte_t pte)
 #define PAGE_AGP		(PAGE_KERNEL_NC)
 #define HAVE_PAGE_AGP
 
-/* Advertise support for _PAGE_SPECIAL */
-#define __HAVE_ARCH_PTE_SPECIAL
-
 #ifndef _PAGE_READ
 /* if not defined, we should not find _PAGE_WRITE too */
 #define _PAGE_READ 0

arch/riscv/Kconfig

@@ -42,6 +42,7 @@ config RISCV
 	select THREAD_INFO_IN_TASK
 	select RISCV_TIMER
 	select GENERIC_IRQ_MULTI_HANDLER
+	select ARCH_HAS_PTE_SPECIAL
 
 config MMU
 	def_bool y

arch/riscv/include/asm/pgtable-bits.h

@@ -42,7 +42,4 @@
 					  _PAGE_WRITE | _PAGE_EXEC |	\
 					  _PAGE_USER | _PAGE_GLOBAL))
 
-/* Advertise support for _PAGE_SPECIAL */
-#define __HAVE_ARCH_PTE_SPECIAL
-
 #endif /* _ASM_RISCV_PGTABLE_BITS_H */

arch/s390/Kconfig

@@ -65,6 +65,7 @@ config S390
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_HAS_GIGANTIC_PAGE if (MEMORY_ISOLATION && COMPACTION) || CMA
 	select ARCH_HAS_KCOV
+	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_SET_MEMORY
 	select ARCH_HAS_SG_CHAIN
 	select ARCH_HAS_STRICT_KERNEL_RWX

arch/s390/include/asm/pgtable.h

@@ -171,7 +171,6 @@ static inline int is_module_addr(void *addr)
 #define _PAGE_WRITE	0x020		/* SW pte write bit */
 #define _PAGE_SPECIAL	0x040		/* SW associated with special page */
 #define _PAGE_UNUSED	0x080		/* SW bit for pgste usage state */
-#define __HAVE_ARCH_PTE_SPECIAL
 
 #ifdef CONFIG_MEM_SOFT_DIRTY
 #define _PAGE_SOFT_DIRTY 0x002		/* SW pte soft dirty bit */

arch/sh/Kconfig

@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 config SUPERH
 	def_bool y
+	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
 	select ARCH_MIGHT_HAVE_PC_PARPORT
 	select ARCH_NO_COHERENT_DMA_MMAP if !MMU

arch/sh/include/asm/pgtable.h

@@ -156,8 +156,6 @@ extern void page_table_range_init(unsigned long start, unsigned long end,
 #define HAVE_ARCH_UNMAPPED_AREA
 #define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
 
-#define __HAVE_ARCH_PTE_SPECIAL
-
 #include <asm-generic/pgtable.h>
 
 #endif /* __ASM_SH_PGTABLE_H */

arch/sparc/Kconfig

@@ -88,6 +88,7 @@ config SPARC64
 	select ARCH_USE_QUEUED_SPINLOCKS
 	select GENERIC_TIME_VSYSCALL
 	select ARCH_CLOCKSOURCE_DATA
+	select ARCH_HAS_PTE_SPECIAL
 
 config ARCH_DEFCONFIG
 	string

arch/sparc/include/asm/pgtable_64.h

@@ -117,9 +117,6 @@ bool kern_addr_valid(unsigned long addr);
 #define _PAGE_PMD_HUGE    _AC(0x0100000000000000,UL) /* Huge page            */
 #define _PAGE_PUD_HUGE    _PAGE_PMD_HUGE
 
-/* Advertise support for _PAGE_SPECIAL */
-#define __HAVE_ARCH_PTE_SPECIAL
-
 /* SUN4U pte bits... */
 #define _PAGE_SZ4MB_4U	  _AC(0x6000000000000000,UL) /* 4MB Page             */
 #define _PAGE_SZ512K_4U	  _AC(0x4000000000000000,UL) /* 512K Page            */

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_SPECIAL
 	select ARCH_HAS_REFCOUNT
 	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
 	select ARCH_HAS_UACCESS_MCSAFE		if X86_64

arch/x86/include/asm/pgtable_types.h

@@ -65,7 +65,6 @@
 #define _PAGE_PKEY_BIT2	(_AT(pteval_t, 0))
 #define _PAGE_PKEY_BIT3	(_AT(pteval_t, 0))
 #endif
-#define __HAVE_ARCH_PTE_SPECIAL
 
 #define _PAGE_PKEY_MASK (_PAGE_PKEY_BIT0 | \
 			 _PAGE_PKEY_BIT1 | \

include/linux/pfn_t.h

@@ -122,7 +122,7 @@ pud_t pud_mkdevmap(pud_t pud);
 #endif
 #endif /* __HAVE_ARCH_PTE_DEVMAP */
 
-#ifdef __HAVE_ARCH_PTE_SPECIAL
+#ifdef CONFIG_ARCH_HAS_PTE_SPECIAL
 static inline bool pfn_t_special(pfn_t pfn)
 {
 	return (pfn.val & PFN_SPECIAL) == PFN_SPECIAL;
@@ -132,5 +132,5 @@ static inline bool pfn_t_special(pfn_t pfn)
 {
 	return false;
 }
-#endif /* __HAVE_ARCH_PTE_SPECIAL */
+#endif /* CONFIG_ARCH_HAS_PTE_SPECIAL */
 #endif /* _LINUX_PFN_T_H_ */

mm/Kconfig

@@ -754,3 +754,6 @@ config GUP_BENCHMARK
 	  performance of get_user_pages_fast().
 
 	  See tools/testing/selftests/vm/gup_benchmark.c
+
+config ARCH_HAS_PTE_SPECIAL
+	bool

mm/gup.c

@@ -1354,7 +1354,7 @@ static void undo_dev_pagemap(int *nr, int nr_start, struct page **pages)
 	}
 }
 
-#ifdef __HAVE_ARCH_PTE_SPECIAL
+#ifdef CONFIG_ARCH_HAS_PTE_SPECIAL
 static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
 			 int write, struct page **pages, int *nr)
 {
@@ -1430,7 +1430,7 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
 {
 	return 0;
 }
-#endif /* __HAVE_ARCH_PTE_SPECIAL */
+#endif /* CONFIG_ARCH_HAS_PTE_SPECIAL */
 
 #if defined(__HAVE_ARCH_PTE_DEVMAP) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
 static int __gup_device_huge(unsigned long pfn, unsigned long addr,

mm/memory.c

@@ -817,7 +817,7 @@ static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
  * PFNMAP mappings in order to support COWable mappings.
  *
  */
-#ifdef __HAVE_ARCH_PTE_SPECIAL
+#ifdef CONFIG_ARCH_HAS_PTE_SPECIAL
 # define HAVE_PTE_SPECIAL 1
 #else
 # define HAVE_PTE_SPECIAL 0