[PATCH 0/6] mm/mmap: Enable more platforms with ARCH_HAS_VM_GET_PAGE_PROT

[PATCH 0/6] mm/mmap: Enable more platforms with ARCH_HAS_VM_GET_PAGE_PROT

[Anshuman Khandual]

From the last discussion [1], some more platforms (s390, mips, csky, nios2,
openrisc) were willing to enable ARCH_HAS_VM_GET_PAGE_PROT and also provide
custom vm_get_page_prot() via switch case statement implementation without
any objection. All those platform specific patches have already been acked.

This series makes protection_map[] array private on platforms which define
their own vm_get_page_prot() via ARCH_HAS_VM_GET_PAGE_PROT, and also drops
off their __PXXX/__SXXX macros. This also enables new platforms as in this
series, to drop off their __PXXX/__SXXX macros as generic protection_map[]
is no longer visible to them.

[1] https://lore.kernel.org/all/1646045273-9343-2-git-send-email-anshuman.khandual@arm.com/

This series applies on current mainline and also has been build tested on
multiple platforms.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: x86@kernel.org
Cc: openrisc@lists.librecores.org
Cc: linux-csky@vger.kernel.org
Cc: linux-mips@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: sparclinux@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org

Anshuman Khandual (6):
  mm/mmap: Restrict generic protection_map[] array visibility
  s390/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
  mips/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
  csky/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
  nios2/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
  openrisc/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

 arch/arm64/include/asm/pgtable-prot.h | 18 --------
 arch/arm64/mm/mmap.c                  | 21 ++++++++++
 arch/csky/Kconfig                     |  1 +
 arch/csky/include/asm/pgtable.h       | 18 --------
 arch/csky/mm/init.c                   | 32 ++++++++++++++
 arch/mips/Kconfig                     |  1 +
 arch/mips/include/asm/pgtable.h       | 22 ----------
 arch/mips/mm/cache.c                  | 60 ++++++++++++++++-----------
 arch/nios2/Kconfig                    |  1 +
 arch/nios2/include/asm/pgtable.h      | 24 -----------
 arch/nios2/mm/init.c                  | 47 +++++++++++++++++++++
 arch/openrisc/Kconfig                 |  1 +
 arch/openrisc/include/asm/pgtable.h   | 18 --------
 arch/openrisc/mm/init.c               | 41 ++++++++++++++++++
 arch/powerpc/include/asm/pgtable.h    |  2 +
 arch/powerpc/mm/book3s64/pgtable.c    | 20 +++++++++
 arch/s390/Kconfig                     |  1 +
 arch/s390/include/asm/pgtable.h       | 17 --------
 arch/s390/mm/mmap.c                   | 33 +++++++++++++++
 arch/sparc/include/asm/pgtable_32.h   |  2 +
 arch/sparc/include/asm/pgtable_64.h   | 19 ---------
 arch/sparc/mm/init_64.c               | 20 +++++++++
 arch/x86/include/asm/pgtable_types.h  | 19 ---------
 arch/x86/mm/pgprot.c                  | 19 +++++++++
 include/linux/mm.h                    |  2 +
 mm/mmap.c                             |  2 +-
 26 files changed, 280 insertions(+), 181 deletions(-)

-- 
2.25.1

[PATCH 1/6] mm/mmap: Restrict generic protection_map[] array visibility

[Anshuman Khandual]

Restrict generic protection_map[] array visibility only for platforms which
do not enable ARCH_HAS_VM_GET_PAGE_PROT. For other platforms that do define
their own vm_get_page_prot() enabling ARCH_HAS_VM_GET_PAGE_PROT, could have
their private static protection_map[] still implementing an array look up.
These private protection_map[] array could do without __PXXX/__SXXX macros,
making them redundant and dropping them off.

But platforms which do not define their custom vm_get_page_prot() enabling
ARCH_HAS_VM_GET_PAGE_PROT, will still have to provide __PXXX/__SXXX macros.
Although this now provides a method for other willing platforms to drop off
__PXXX/__SXX macros completely.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: x86@kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: sparclinux@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 arch/arm64/include/asm/pgtable-prot.h | 18 ------------------
 arch/arm64/mm/mmap.c                  | 21 +++++++++++++++++++++
 arch/powerpc/include/asm/pgtable.h    |  2 ++
 arch/powerpc/mm/book3s64/pgtable.c    | 20 ++++++++++++++++++++
 arch/sparc/include/asm/pgtable_32.h   |  2 ++
 arch/sparc/include/asm/pgtable_64.h   | 19 -------------------
 arch/sparc/mm/init_64.c               | 20 ++++++++++++++++++++
 arch/x86/include/asm/pgtable_types.h  | 19 -------------------
 arch/x86/mm/pgprot.c                  | 19 +++++++++++++++++++
 include/linux/mm.h                    |  2 ++
 mm/mmap.c                             |  2 +-
 11 files changed, 87 insertions(+), 57 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h
index 62e0ebeed720..9b165117a454 100644
--- a/arch/arm64/include/asm/pgtable-prot.h
+++ b/arch/arm64/include/asm/pgtable-prot.h
@@ -89,24 +89,6 @@ extern bool arm64_use_ng_mappings;
 #define PAGE_READONLY_EXEC	__pgprot(_PAGE_DEFAULT | PTE_USER | PTE_RDONLY | PTE_NG | PTE_PXN)
 #define PAGE_EXECONLY		__pgprot(_PAGE_DEFAULT | PTE_RDONLY | PTE_NG | PTE_PXN)
 
-#define __P000  PAGE_NONE
-#define __P001  PAGE_READONLY
-#define __P010  PAGE_READONLY
-#define __P011  PAGE_READONLY
-#define __P100  PAGE_READONLY_EXEC	/* PAGE_EXECONLY if Enhanced PAN */
-#define __P101  PAGE_READONLY_EXEC
-#define __P110  PAGE_READONLY_EXEC
-#define __P111  PAGE_READONLY_EXEC
-
-#define __S000  PAGE_NONE
-#define __S001  PAGE_READONLY
-#define __S010  PAGE_SHARED
-#define __S011  PAGE_SHARED
-#define __S100  PAGE_READONLY_EXEC	/* PAGE_EXECONLY if Enhanced PAN */
-#define __S101  PAGE_READONLY_EXEC
-#define __S110  PAGE_SHARED_EXEC
-#define __S111  PAGE_SHARED_EXEC
-
 #endif /* __ASSEMBLY__ */
 
 #endif /* __ASM_PGTABLE_PROT_H */
diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c
index 78e9490f748d..8f5b7ce857ed 100644
--- a/arch/arm64/mm/mmap.c
+++ b/arch/arm64/mm/mmap.c
@@ -13,6 +13,27 @@
 #include <asm/cpufeature.h>
 #include <asm/page.h>
 
+static pgprot_t protection_map[16] __ro_after_init = {
+	[VM_NONE]					= PAGE_NONE,
+	[VM_READ]					= PAGE_READONLY,
+	[VM_WRITE]					= PAGE_READONLY,
+	[VM_WRITE | VM_READ]				= PAGE_READONLY,
+	/* PAGE_EXECONLY if Enhanced PAN */
+	[VM_EXEC]					= PAGE_READONLY_EXEC,
+	[VM_EXEC | VM_READ]				= PAGE_READONLY_EXEC,
+	[VM_EXEC | VM_WRITE]				= PAGE_READONLY_EXEC,
+	[VM_EXEC | VM_WRITE | VM_READ]			= PAGE_READONLY_EXEC,
+	[VM_SHARED]					= PAGE_NONE,
+	[VM_SHARED | VM_READ]				= PAGE_READONLY,
+	[VM_SHARED | VM_WRITE]				= PAGE_SHARED,
+	[VM_SHARED | VM_WRITE | VM_READ]		= PAGE_SHARED,
+	/* PAGE_EXECONLY if Enhanced PAN */
+	[VM_SHARED | VM_EXEC]				= PAGE_READONLY_EXEC,
+	[VM_SHARED | VM_EXEC | VM_READ]			= PAGE_READONLY_EXEC,
+	[VM_SHARED | VM_EXEC | VM_WRITE]		= PAGE_SHARED_EXEC,
+	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= PAGE_SHARED_EXEC
+};
+
 /*
  * You really shouldn't be using read() or write() on /dev/mem.  This might go
  * away in the future.
diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
index d564d0ecd4cd..8ed2a80c896e 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h
@@ -21,6 +21,7 @@ struct mm_struct;
 #endif /* !CONFIG_PPC_BOOK3S */
 
 /* Note due to the way vm flags are laid out, the bits are XWR */
+#ifndef CONFIG_ARCH_HAS_VM_GET_PAGE_PROT
 #define __P000	PAGE_NONE
 #define __P001	PAGE_READONLY
 #define __P010	PAGE_COPY
@@ -38,6 +39,7 @@ struct mm_struct;
 #define __S101	PAGE_READONLY_X
 #define __S110	PAGE_SHARED_X
 #define __S111	PAGE_SHARED_X
+#endif
 
 #ifndef __ASSEMBLY__
 
diff --git a/arch/powerpc/mm/book3s64/pgtable.c b/arch/powerpc/mm/book3s64/pgtable.c
index 7b9966402b25..2cf10a17c0a9 100644
--- a/arch/powerpc/mm/book3s64/pgtable.c
+++ b/arch/powerpc/mm/book3s64/pgtable.c
@@ -551,6 +551,26 @@ unsigned long memremap_compat_align(void)
 EXPORT_SYMBOL_GPL(memremap_compat_align);
 #endif
 
+/* Note due to the way vm flags are laid out, the bits are XWR */
+static pgprot_t protection_map[16] __ro_after_init = {
+	[VM_NONE]					= PAGE_NONE,
+	[VM_READ]					= PAGE_READONLY,
+	[VM_WRITE]					= PAGE_COPY,
+	[VM_WRITE | VM_READ]				= PAGE_COPY,
+	[VM_EXEC]					= PAGE_READONLY_X,
+	[VM_EXEC | VM_READ]				= PAGE_READONLY_X,
+	[VM_EXEC | VM_WRITE]				= PAGE_COPY_X,
+	[VM_EXEC | VM_WRITE | VM_READ]			= PAGE_COPY_X,
+	[VM_SHARED]					= PAGE_NONE,
+	[VM_SHARED | VM_READ]				= PAGE_READONLY,
+	[VM_SHARED | VM_WRITE]				= PAGE_SHARED,
+	[VM_SHARED | VM_WRITE | VM_READ]		= PAGE_SHARED,
+	[VM_SHARED | VM_EXEC]				= PAGE_READONLY_X,
+	[VM_SHARED | VM_EXEC | VM_READ]			= PAGE_READONLY_X,
+	[VM_SHARED | VM_EXEC | VM_WRITE]		= PAGE_SHARED_X,
+	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= PAGE_SHARED_X
+};
+
 pgprot_t vm_get_page_prot(unsigned long vm_flags)
 {
 	unsigned long prot = pgprot_val(protection_map[vm_flags &
diff --git a/arch/sparc/include/asm/pgtable_32.h b/arch/sparc/include/asm/pgtable_32.h
index 4866625da314..bca98b280fdd 100644
--- a/arch/sparc/include/asm/pgtable_32.h
+++ b/arch/sparc/include/asm/pgtable_32.h
@@ -65,6 +65,7 @@ void paging_init(void);
 extern unsigned long ptr_in_current_pgd;
 
 /*         xwr */
+#ifndef CONFIG_ARCH_HAS_VM_GET_PAGE_PROT
 #define __P000  PAGE_NONE
 #define __P001  PAGE_READONLY
 #define __P010  PAGE_COPY
@@ -82,6 +83,7 @@ extern unsigned long ptr_in_current_pgd;
 #define __S101	PAGE_READONLY
 #define __S110	PAGE_SHARED
 #define __S111	PAGE_SHARED
+#endif
 
 /* First physical page can be anywhere, the following is needed so that
  * va-->pa and vice versa conversions work properly without performance
diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
index 4679e45c8348..a779418ceba9 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -187,25 +187,6 @@ bool kern_addr_valid(unsigned long addr);
 #define _PAGE_SZHUGE_4U	_PAGE_SZ4MB_4U
 #define _PAGE_SZHUGE_4V	_PAGE_SZ4MB_4V
 
-/* These are actually filled in at boot time by sun4{u,v}_pgprot_init() */
-#define __P000	__pgprot(0)
-#define __P001	__pgprot(0)
-#define __P010	__pgprot(0)
-#define __P011	__pgprot(0)
-#define __P100	__pgprot(0)
-#define __P101	__pgprot(0)
-#define __P110	__pgprot(0)
-#define __P111	__pgprot(0)
-
-#define __S000	__pgprot(0)
-#define __S001	__pgprot(0)
-#define __S010	__pgprot(0)
-#define __S011	__pgprot(0)
-#define __S100	__pgprot(0)
-#define __S101	__pgprot(0)
-#define __S110	__pgprot(0)
-#define __S111	__pgprot(0)
-
 #ifndef __ASSEMBLY__
 
 pte_t mk_pte_io(unsigned long, pgprot_t, int, unsigned long);
diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
index f6174df2d5af..6edc2a68b73c 100644
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -2634,6 +2634,26 @@ void vmemmap_free(unsigned long start, unsigned long end,
 }
 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
 
+/* These are actually filled in at boot time by sun4{u,v}_pgprot_init() */
+static pgprot_t protection_map[16] __ro_after_init = {
+	[VM_NONE]					= __pgprot(0),
+	[VM_READ]					= __pgprot(0),
+	[VM_WRITE]					= __pgprot(0),
+	[VM_WRITE | VM_READ]				= __pgprot(0),
+	[VM_EXEC]					= __pgprot(0),
+	[VM_EXEC | VM_READ]				= __pgprot(0),
+	[VM_EXEC | VM_WRITE]				= __pgprot(0),
+	[VM_EXEC | VM_WRITE | VM_READ]			= __pgprot(0),
+	[VM_SHARED]					= __pgprot(0),
+	[VM_SHARED | VM_READ]				= __pgprot(0),
+	[VM_SHARED | VM_WRITE]				= __pgprot(0),
+	[VM_SHARED | VM_WRITE | VM_READ]		= __pgprot(0),
+	[VM_SHARED | VM_EXEC]				= __pgprot(0),
+	[VM_SHARED | VM_EXEC | VM_READ]			= __pgprot(0),
+	[VM_SHARED | VM_EXEC | VM_WRITE]		= __pgprot(0),
+	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= __pgprot(0)
+};
+
 static void prot_init_common(unsigned long page_none,
 			     unsigned long page_shared,
 			     unsigned long page_copy,
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index bdaf8391e2e0..aa174fed3a71 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -230,25 +230,6 @@ enum page_cache_mode {
 
 #endif	/* __ASSEMBLY__ */
 
-/*         xwr */
-#define __P000	PAGE_NONE
-#define __P001	PAGE_READONLY
-#define __P010	PAGE_COPY
-#define __P011	PAGE_COPY
-#define __P100	PAGE_READONLY_EXEC
-#define __P101	PAGE_READONLY_EXEC
-#define __P110	PAGE_COPY_EXEC
-#define __P111	PAGE_COPY_EXEC
-
-#define __S000	PAGE_NONE
-#define __S001	PAGE_READONLY
-#define __S010	PAGE_SHARED
-#define __S011	PAGE_SHARED
-#define __S100	PAGE_READONLY_EXEC
-#define __S101	PAGE_READONLY_EXEC
-#define __S110	PAGE_SHARED_EXEC
-#define __S111	PAGE_SHARED_EXEC
-
 /*
  * early identity mapping  pte attrib macros.
  */
diff --git a/arch/x86/mm/pgprot.c b/arch/x86/mm/pgprot.c
index 763742782286..7eca1b009af6 100644
--- a/arch/x86/mm/pgprot.c
+++ b/arch/x86/mm/pgprot.c
@@ -4,6 +4,25 @@
 #include <linux/mm.h>
 #include <asm/pgtable.h>
 
+static pgprot_t protection_map[16] __ro_after_init = {
+	[VM_NONE]					= PAGE_NONE,
+	[VM_READ]					= PAGE_READONLY,
+	[VM_WRITE]					= PAGE_COPY,
+	[VM_WRITE | VM_READ]				= PAGE_COPY,
+	[VM_EXEC]					= PAGE_READONLY_EXEC,
+	[VM_EXEC | VM_READ]				= PAGE_READONLY_EXEC,
+	[VM_EXEC | VM_WRITE]				= PAGE_COPY_EXEC,
+	[VM_EXEC | VM_WRITE | VM_READ]			= PAGE_COPY_EXEC,
+	[VM_SHARED]					= PAGE_NONE,
+	[VM_SHARED | VM_READ]				= PAGE_READONLY,
+	[VM_SHARED | VM_WRITE]				= PAGE_SHARED,
+	[VM_SHARED | VM_WRITE | VM_READ]		= PAGE_SHARED,
+	[VM_SHARED | VM_EXEC]				= PAGE_READONLY_EXEC,
+	[VM_SHARED | VM_EXEC | VM_READ]			= PAGE_READONLY_EXEC,
+	[VM_SHARED | VM_EXEC | VM_WRITE]		= PAGE_SHARED_EXEC,
+	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= PAGE_SHARED_EXEC
+};
+
 pgprot_t vm_get_page_prot(unsigned long vm_flags)
 {
 	unsigned long val = pgprot_val(protection_map[vm_flags &
diff --git a/include/linux/mm.h b/include/linux/mm.h
index bc8f326be0ce..2254c1980c8e 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -420,11 +420,13 @@ extern unsigned int kobjsize(const void *objp);
 #endif
 #define VM_FLAGS_CLEAR	(ARCH_VM_PKEY_FLAGS | VM_ARCH_CLEAR)
 
+#ifndef CONFIG_ARCH_HAS_VM_GET_PAGE_PROT
 /*
  * mapping from the currently active vm_flags protection bits (the
  * low four bits) to a page protection mask..
  */
 extern pgprot_t protection_map[16];
+#endif
 
 /*
  * The default fault flags that should be used by most of the
diff --git a/mm/mmap.c b/mm/mmap.c
index 61e6135c54ef..e66920414945 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -101,6 +101,7 @@ static void unmap_region(struct mm_struct *mm,
  *								w: (no) no
  *								x: (yes) yes
  */
+#ifndef CONFIG_ARCH_HAS_VM_GET_PAGE_PROT
 pgprot_t protection_map[16] __ro_after_init = {
 	[VM_NONE]					= __P000,
 	[VM_READ]					= __P001,
@@ -120,7 +121,6 @@ pgprot_t protection_map[16] __ro_after_init = {
 	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= __S111
 };
 
-#ifndef CONFIG_ARCH_HAS_VM_GET_PAGE_PROT
 pgprot_t vm_get_page_prot(unsigned long vm_flags)
 {
 	return protection_map[vm_flags & (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)];
-- 
2.25.1

[PATCH 2/6] s390/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

[Anshuman Khandual]

This defines and exports a platform specific custom vm_get_page_prot() via
subscribing ARCH_HAS_VM_GET_PAGE_PROT. Subsequently all __SXXX and __PXXX
macros can be dropped which are no longer needed.

Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Acked-by: Sven Schnelle <svens@linux.ibm.com>
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 arch/s390/Kconfig               |  1 +
 arch/s390/include/asm/pgtable.h | 17 -----------------
 arch/s390/mm/mmap.c             | 33 +++++++++++++++++++++++++++++++++
 3 files changed, 34 insertions(+), 17 deletions(-)

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index b17239ae7bd4..cdcf678deab1 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -81,6 +81,7 @@ config S390
 	select ARCH_HAS_SYSCALL_WRAPPER
 	select ARCH_HAS_UBSAN_SANITIZE_ALL
 	select ARCH_HAS_VDSO_DATA
+	select ARCH_HAS_VM_GET_PAGE_PROT
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
 	select ARCH_INLINE_READ_LOCK
 	select ARCH_INLINE_READ_LOCK_BH
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index a397b072a580..c63a05b5368a 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -424,23 +424,6 @@ static inline int is_module_addr(void *addr)
  * implies read permission.
  */
          /*xwr*/
-#define __P000	PAGE_NONE
-#define __P001	PAGE_RO
-#define __P010	PAGE_RO
-#define __P011	PAGE_RO
-#define __P100	PAGE_RX
-#define __P101	PAGE_RX
-#define __P110	PAGE_RX
-#define __P111	PAGE_RX
-
-#define __S000	PAGE_NONE
-#define __S001	PAGE_RO
-#define __S010	PAGE_RW
-#define __S011	PAGE_RW
-#define __S100	PAGE_RX
-#define __S101	PAGE_RX
-#define __S110	PAGE_RWX
-#define __S111	PAGE_RWX
 
 /*
  * Segment entry (large page) protection definitions.
diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
index d545f5c39f7e..11d75b8d5ec0 100644
--- a/arch/s390/mm/mmap.c
+++ b/arch/s390/mm/mmap.c
@@ -188,3 +188,36 @@ void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack)
 		mm->get_unmapped_area = arch_get_unmapped_area_topdown;
 	}
 }
+
+pgprot_t vm_get_page_prot(unsigned long vm_flags)
+{
+	switch (vm_flags & (VM_READ | VM_WRITE | VM_EXEC | VM_SHARED)) {
+	case VM_NONE:
+		return PAGE_NONE;
+	case VM_READ:
+	case VM_WRITE:
+	case VM_WRITE | VM_READ:
+		return PAGE_RO;
+	case VM_EXEC:
+	case VM_EXEC | VM_READ:
+	case VM_EXEC | VM_WRITE:
+	case VM_EXEC | VM_WRITE | VM_READ:
+		return PAGE_RX;
+	case VM_SHARED:
+		return PAGE_NONE;
+	case VM_SHARED | VM_READ:
+		return PAGE_RO;
+	case VM_SHARED | VM_WRITE:
+	case VM_SHARED | VM_WRITE | VM_READ:
+		return PAGE_RW;
+	case VM_SHARED | VM_EXEC:
+	case VM_SHARED | VM_EXEC | VM_READ:
+		return PAGE_RX;
+	case VM_SHARED | VM_EXEC | VM_WRITE:
+	case VM_SHARED | VM_EXEC | VM_WRITE | VM_READ:
+		return PAGE_RWX;
+	default:
+		BUILD_BUG();
+	}
+}
+EXPORT_SYMBOL(vm_get_page_prot);
-- 
2.25.1

[PATCH 3/6] mips/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

[Anshuman Khandual]

This defines and exports a platform specific custom vm_get_page_prot() via
subscribing ARCH_HAS_VM_GET_PAGE_PROT. Subsequently all __SXXX and __PXXX
macros can be dropped which are no longer needed.

Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 arch/mips/Kconfig               |  1 +
 arch/mips/include/asm/pgtable.h | 22 ------------
 arch/mips/mm/cache.c            | 60 +++++++++++++++++++--------------
 3 files changed, 36 insertions(+), 47 deletions(-)

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index db09d45d59ec..d0b7eb11ec81 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -14,6 +14,7 @@ config MIPS
 	select ARCH_HAS_STRNLEN_USER
 	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
 	select ARCH_HAS_UBSAN_SANITIZE_ALL
+	select ARCH_HAS_VM_GET_PAGE_PROT
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_KEEP_MEMBLOCK
 	select ARCH_SUPPORTS_UPROBES
diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
index 374c6322775d..6caec386ad2f 100644
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -41,28 +41,6 @@ struct vm_area_struct;
  * by reasonable means..
  */
 
-/*
- * Dummy values to fill the table in mmap.c
- * The real values will be generated at runtime
- */
-#define __P000 __pgprot(0)
-#define __P001 __pgprot(0)
-#define __P010 __pgprot(0)
-#define __P011 __pgprot(0)
-#define __P100 __pgprot(0)
-#define __P101 __pgprot(0)
-#define __P110 __pgprot(0)
-#define __P111 __pgprot(0)
-
-#define __S000 __pgprot(0)
-#define __S001 __pgprot(0)
-#define __S010 __pgprot(0)
-#define __S011 __pgprot(0)
-#define __S100 __pgprot(0)
-#define __S101 __pgprot(0)
-#define __S110 __pgprot(0)
-#define __S111 __pgprot(0)
-
 extern unsigned long _page_cachable_default;
 extern void __update_cache(unsigned long address, pte_t pte);
 
diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c
index 7be7240f7703..012862004431 100644
--- a/arch/mips/mm/cache.c
+++ b/arch/mips/mm/cache.c
@@ -159,30 +159,6 @@ EXPORT_SYMBOL(_page_cachable_default);
 
 #define PM(p)	__pgprot(_page_cachable_default | (p))
 
-static inline void setup_protection_map(void)
-{
-	protection_map[0]  = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
-	protection_map[1]  = PM(_PAGE_PRESENT | _PAGE_NO_EXEC);
-	protection_map[2]  = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
-	protection_map[3]  = PM(_PAGE_PRESENT | _PAGE_NO_EXEC);
-	protection_map[4]  = PM(_PAGE_PRESENT);
-	protection_map[5]  = PM(_PAGE_PRESENT);
-	protection_map[6]  = PM(_PAGE_PRESENT);
-	protection_map[7]  = PM(_PAGE_PRESENT);
-
-	protection_map[8]  = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
-	protection_map[9]  = PM(_PAGE_PRESENT | _PAGE_NO_EXEC);
-	protection_map[10] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE |
-				_PAGE_NO_READ);
-	protection_map[11] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE);
-	protection_map[12] = PM(_PAGE_PRESENT);
-	protection_map[13] = PM(_PAGE_PRESENT);
-	protection_map[14] = PM(_PAGE_PRESENT | _PAGE_WRITE);
-	protection_map[15] = PM(_PAGE_PRESENT | _PAGE_WRITE);
-}
-
-#undef PM
-
 void cpu_cache_init(void)
 {
 	if (cpu_has_3k_cache) {
@@ -201,6 +177,40 @@ void cpu_cache_init(void)
 
 		octeon_cache_init();
 	}
+}
 
-	setup_protection_map();
+pgprot_t vm_get_page_prot(unsigned long vm_flags)
+{
+	switch (vm_flags & (VM_READ | VM_WRITE | VM_EXEC | VM_SHARED)) {
+	case VM_NONE:
+		return PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
+	case VM_READ:
+		return PM(_PAGE_PRESENT | _PAGE_NO_EXEC);
+	case VM_WRITE:
+		return PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
+	case VM_WRITE | VM_READ:
+		return PM(_PAGE_PRESENT | _PAGE_NO_EXEC);
+	case VM_EXEC:
+	case VM_EXEC | VM_READ:
+	case VM_EXEC | VM_WRITE:
+	case VM_EXEC | VM_WRITE | VM_READ:
+		return PM(_PAGE_PRESENT);
+	case VM_SHARED:
+		return PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
+	case VM_SHARED | VM_READ:
+		return PM(_PAGE_PRESENT | _PAGE_NO_EXEC);
+	case VM_SHARED | VM_WRITE:
+		return PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE | _PAGE_NO_READ);
+	case VM_SHARED | VM_WRITE | VM_READ:
+		return PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE);
+	case VM_SHARED | VM_EXEC:
+	case VM_SHARED | VM_EXEC | VM_READ:
+		return PM(_PAGE_PRESENT);
+	case VM_SHARED | VM_EXEC | VM_WRITE:
+	case VM_SHARED | VM_EXEC | VM_WRITE | VM_READ:
+		return PM(_PAGE_PRESENT | _PAGE_WRITE);
+	default:
+		BUILD_BUG();
+	}
 }
+EXPORT_SYMBOL(vm_get_page_prot);
-- 
2.25.1

[PATCH 4/6] csky/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

[Anshuman Khandual]

This defines and exports a platform specific custom vm_get_page_prot() via
subscribing ARCH_HAS_VM_GET_PAGE_PROT. Subsequently all __SXXX and __PXXX
macros can be dropped which are no longer needed.

Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: linux-csky@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Acked-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 arch/csky/Kconfig               |  1 +
 arch/csky/include/asm/pgtable.h | 18 ------------------
 arch/csky/mm/init.c             | 32 ++++++++++++++++++++++++++++++++
 3 files changed, 33 insertions(+), 18 deletions(-)

diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
index 21d72b078eef..588b8a9c68ed 100644
--- a/arch/csky/Kconfig
+++ b/arch/csky/Kconfig
@@ -6,6 +6,7 @@ config CSKY
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_HAS_SYNC_DMA_FOR_CPU
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
+	select ARCH_HAS_VM_GET_PAGE_PROT
 	select ARCH_USE_BUILTIN_BSWAP
 	select ARCH_USE_QUEUED_RWLOCKS
 	select ARCH_WANT_FRAME_POINTERS if !CPU_CK610 && $(cc-option,-mbacktrace)
diff --git a/arch/csky/include/asm/pgtable.h b/arch/csky/include/asm/pgtable.h
index bbe245117777..229a5f4ad7fc 100644
--- a/arch/csky/include/asm/pgtable.h
+++ b/arch/csky/include/asm/pgtable.h
@@ -77,24 +77,6 @@
 #define MAX_SWAPFILES_CHECK() \
 		BUILD_BUG_ON(MAX_SWAPFILES_SHIFT != 5)
 
-#define __P000	PAGE_NONE
-#define __P001	PAGE_READ
-#define __P010	PAGE_READ
-#define __P011	PAGE_READ
-#define __P100	PAGE_READ
-#define __P101	PAGE_READ
-#define __P110	PAGE_READ
-#define __P111	PAGE_READ
-
-#define __S000	PAGE_NONE
-#define __S001	PAGE_READ
-#define __S010	PAGE_WRITE
-#define __S011	PAGE_WRITE
-#define __S100	PAGE_READ
-#define __S101	PAGE_READ
-#define __S110	PAGE_WRITE
-#define __S111	PAGE_WRITE
-
 extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
 #define ZERO_PAGE(vaddr)	(virt_to_page(empty_zero_page))
 
diff --git a/arch/csky/mm/init.c b/arch/csky/mm/init.c
index bf2004aa811a..f9babbed17d4 100644
--- a/arch/csky/mm/init.c
+++ b/arch/csky/mm/init.c
@@ -197,3 +197,35 @@ void __init fixaddr_init(void)
 	vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 	fixrange_init(vaddr, vaddr + PMD_SIZE, swapper_pg_dir);
 }
+
+pgprot_t vm_get_page_prot(unsigned long vm_flags)
+{
+	switch (vm_flags & (VM_READ | VM_WRITE | VM_EXEC | VM_SHARED)) {
+	case VM_NONE:
+		return PAGE_NONE;
+	case VM_READ:
+	case VM_WRITE:
+	case VM_WRITE | VM_READ:
+	case VM_EXEC:
+	case VM_EXEC | VM_READ:
+	case VM_EXEC | VM_WRITE:
+	case VM_EXEC | VM_WRITE | VM_READ:
+		return PAGE_READ;
+	case VM_SHARED:
+		return PAGE_NONE;
+	case VM_SHARED | VM_READ:
+		return PAGE_READ;
+	case VM_SHARED | VM_WRITE:
+	case VM_SHARED | VM_WRITE | VM_READ:
+		return PAGE_WRITE;
+	case VM_SHARED | VM_EXEC:
+	case VM_SHARED | VM_EXEC | VM_READ:
+		return PAGE_READ;
+	case VM_SHARED | VM_EXEC | VM_WRITE:
+	case VM_SHARED | VM_EXEC | VM_WRITE | VM_READ:
+		return PAGE_WRITE;
+	default:
+		BUILD_BUG();
+	}
+}
+EXPORT_SYMBOL(vm_get_page_prot);
-- 
2.25.1

[PATCH 5/6] nios2/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

[Anshuman Khandual]

This defines and exports a platform specific custom vm_get_page_prot() via
subscribing ARCH_HAS_VM_GET_PAGE_PROT. Subsequently all __SXXX and __PXXX
macros can be dropped which are no longer needed.

Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: linux-kernel@vger.kernel.org
Acked-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 arch/nios2/Kconfig               |  1 +
 arch/nios2/include/asm/pgtable.h | 24 ----------------
 arch/nios2/mm/init.c             | 47 ++++++++++++++++++++++++++++++++
 3 files changed, 48 insertions(+), 24 deletions(-)

diff --git a/arch/nios2/Kconfig b/arch/nios2/Kconfig
index 4167f1eb4cd8..e0459dffd218 100644
--- a/arch/nios2/Kconfig
+++ b/arch/nios2/Kconfig
@@ -6,6 +6,7 @@ config NIOS2
 	select ARCH_HAS_SYNC_DMA_FOR_CPU
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
 	select ARCH_HAS_DMA_SET_UNCACHED
+	select ARCH_HAS_VM_GET_PAGE_PROT
 	select ARCH_NO_SWAP
 	select COMMON_CLK
 	select TIMER_OF
diff --git a/arch/nios2/include/asm/pgtable.h b/arch/nios2/include/asm/pgtable.h
index 262d0609268c..3c9f83c22733 100644
--- a/arch/nios2/include/asm/pgtable.h
+++ b/arch/nios2/include/asm/pgtable.h
@@ -34,30 +34,6 @@ struct mm_struct;
 				((x) ? _PAGE_EXEC : 0) |		\
 				((r) ? _PAGE_READ : 0) |		\
 				((w) ? _PAGE_WRITE : 0))
-/*
- * These are the macros that generic kernel code needs
- * (to populate protection_map[])
- */
-
-/* Remove W bit on private pages for COW support */
-#define __P000	MKP(0, 0, 0)
-#define __P001	MKP(0, 0, 1)
-#define __P010	MKP(0, 0, 0)	/* COW */
-#define __P011	MKP(0, 0, 1)	/* COW */
-#define __P100	MKP(1, 0, 0)
-#define __P101	MKP(1, 0, 1)
-#define __P110	MKP(1, 0, 0)	/* COW */
-#define __P111	MKP(1, 0, 1)	/* COW */
-
-/* Shared pages can have exact HW mapping */
-#define __S000	MKP(0, 0, 0)
-#define __S001	MKP(0, 0, 1)
-#define __S010	MKP(0, 1, 0)
-#define __S011	MKP(0, 1, 1)
-#define __S100	MKP(1, 0, 0)
-#define __S101	MKP(1, 0, 1)
-#define __S110	MKP(1, 1, 0)
-#define __S111	MKP(1, 1, 1)
 
 /* Used all over the kernel */
 #define PAGE_KERNEL __pgprot(_PAGE_PRESENT | _PAGE_CACHED | _PAGE_READ | \
diff --git a/arch/nios2/mm/init.c b/arch/nios2/mm/init.c
index 613fcaa5988a..e867f5d85580 100644
--- a/arch/nios2/mm/init.c
+++ b/arch/nios2/mm/init.c
@@ -124,3 +124,50 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 {
 	return (vma->vm_start == KUSER_BASE) ? "[kuser]" : NULL;
 }
+
+pgprot_t vm_get_page_prot(unsigned long vm_flags)
+{
+	switch (vm_flags & (VM_READ | VM_WRITE | VM_EXEC | VM_SHARED)) {
+	/* Remove W bit on private pages for COW support */
+	case VM_NONE:
+		return MKP(0, 0, 0);
+	case VM_READ:
+		return MKP(0, 0, 1);
+	/* COW */
+	case VM_WRITE:
+		return MKP(0, 0, 0);
+	/* COW */
+	case VM_WRITE | VM_READ:
+		return MKP(0, 0, 1);
+	case VM_EXEC:
+		return MKP(1, 0, 0);
+	case VM_EXEC | VM_READ:
+		return MKP(1, 0, 1);
+	/* COW */
+	case VM_EXEC | VM_WRITE:
+		return MKP(1, 0, 0);
+	/* COW */
+	case VM_EXEC | VM_WRITE | VM_READ:
+		return MKP(1, 0, 1);
+	/* Shared pages can have exact HW mapping */
+	case VM_SHARED:
+		return MKP(0, 0, 0);
+	case VM_SHARED | VM_READ:
+		return MKP(0, 0, 1);
+	case VM_SHARED | VM_WRITE:
+		return MKP(0, 1, 0);
+	case VM_SHARED | VM_WRITE | VM_READ:
+		return MKP(0, 1, 1);
+	case VM_SHARED | VM_EXEC:
+		return MKP(1, 0, 0);
+	case VM_SHARED | VM_EXEC | VM_READ:
+		return MKP(1, 0, 1);
+	case VM_SHARED | VM_EXEC | VM_WRITE:
+		return MKP(1, 1, 0);
+	case VM_SHARED | VM_EXEC | VM_WRITE | VM_READ:
+		return MKP(1, 1, 1);
+	default:
+		BUILD_BUG();
+	}
+}
+EXPORT_SYMBOL(vm_get_page_prot);
-- 
2.25.1

[PATCH 6/6] openrisc/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

[Anshuman Khandual]

This defines and exports a platform specific custom vm_get_page_prot() via
subscribing ARCH_HAS_VM_GET_PAGE_PROT. Subsequently all __SXXX and __PXXX
macros can be dropped which are no longer needed.

Cc: Jonas Bonn <jonas@southpole.se>
Cc: openrisc@lists.librecores.org
Cc: linux-kernel@vger.kernel.org
Acked-by: Stafford Horne <shorne@gmail.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 arch/openrisc/Kconfig               |  1 +
 arch/openrisc/include/asm/pgtable.h | 18 -------------
 arch/openrisc/mm/init.c             | 41 +++++++++++++++++++++++++++++
 3 files changed, 42 insertions(+), 18 deletions(-)

diff --git a/arch/openrisc/Kconfig b/arch/openrisc/Kconfig
index e814df4c483c..fe0dfb50eb86 100644
--- a/arch/openrisc/Kconfig
+++ b/arch/openrisc/Kconfig
@@ -10,6 +10,7 @@ config OPENRISC
 	select ARCH_HAS_DMA_SET_UNCACHED
 	select ARCH_HAS_DMA_CLEAR_UNCACHED
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
+	select ARCH_HAS_VM_GET_PAGE_PROT
 	select COMMON_CLK
 	select OF
 	select OF_EARLY_FLATTREE
diff --git a/arch/openrisc/include/asm/pgtable.h b/arch/openrisc/include/asm/pgtable.h
index c3abbf71e09f..dcae8aea132f 100644
--- a/arch/openrisc/include/asm/pgtable.h
+++ b/arch/openrisc/include/asm/pgtable.h
@@ -176,24 +176,6 @@ extern void paging_init(void);
 	__pgprot(_PAGE_ALL | _PAGE_SRE | _PAGE_SWE \
 		 | _PAGE_SHARED | _PAGE_DIRTY | _PAGE_EXEC | _PAGE_CI)
 
-#define __P000	PAGE_NONE
-#define __P001	PAGE_READONLY_X
-#define __P010	PAGE_COPY
-#define __P011	PAGE_COPY_X
-#define __P100	PAGE_READONLY
-#define __P101	PAGE_READONLY_X
-#define __P110	PAGE_COPY
-#define __P111	PAGE_COPY_X
-
-#define __S000	PAGE_NONE
-#define __S001	PAGE_READONLY_X
-#define __S010	PAGE_SHARED
-#define __S011	PAGE_SHARED_X
-#define __S100	PAGE_READONLY
-#define __S101	PAGE_READONLY_X
-#define __S110	PAGE_SHARED
-#define __S111	PAGE_SHARED_X
-
 /* zero page used for uninitialized stuff */
 extern unsigned long empty_zero_page[2048];
 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
diff --git a/arch/openrisc/mm/init.c b/arch/openrisc/mm/init.c
index 3a021ab6f1ae..266dc68c32e5 100644
--- a/arch/openrisc/mm/init.c
+++ b/arch/openrisc/mm/init.c
@@ -208,3 +208,44 @@ void __init mem_init(void)
 	mem_init_done = 1;
 	return;
 }
+
+pgprot_t vm_get_page_prot(unsigned long vm_flags)
+{
+	switch (vm_flags & (VM_READ | VM_WRITE | VM_EXEC | VM_SHARED)) {
+	case VM_NONE:
+		return PAGE_NONE;
+	case VM_READ:
+		return PAGE_READONLY_X;
+	case VM_WRITE:
+		return PAGE_COPY;
+	case VM_WRITE | VM_READ:
+		return PAGE_COPY_X;
+	case VM_EXEC:
+		return PAGE_READONLY;
+	case VM_EXEC | VM_READ:
+		return PAGE_READONLY_X;
+	case VM_EXEC | VM_WRITE:
+		return PAGE_COPY;
+	case VM_EXEC | VM_WRITE | VM_READ:
+		return PAGE_COPY_X;
+	case VM_SHARED:
+		return PAGE_NONE;
+	case VM_SHARED | VM_READ:
+		return PAGE_READONLY_X;
+	case VM_SHARED | VM_WRITE:
+		return PAGE_SHARED;
+	case VM_SHARED | VM_WRITE | VM_READ:
+		return PAGE_SHARED_X;
+	case VM_SHARED | VM_EXEC:
+		return PAGE_READONLY;
+	case VM_SHARED | VM_EXEC | VM_READ:
+		return PAGE_READONLY_X;
+	case VM_SHARED | VM_EXEC | VM_WRITE:
+		return PAGE_SHARED;
+	case VM_SHARED | VM_EXEC | VM_WRITE | VM_READ:
+		return PAGE_SHARED_X;
+	default:
+		BUILD_BUG();
+	}
+}
+EXPORT_SYMBOL(vm_get_page_prot);
-- 
2.25.1

Re: [PATCH 1/6] mm/mmap: Restrict generic protection_map[] array visibility

[Christophe Leroy]

Le 03/06/2022 à 12:14, Anshuman Khandual a écrit :
> Restrict generic protection_map[] array visibility only for platforms which
> do not enable ARCH_HAS_VM_GET_PAGE_PROT. For other platforms that do define
> their own vm_get_page_prot() enabling ARCH_HAS_VM_GET_PAGE_PROT, could have
> their private static protection_map[] still implementing an array look up.
> These private protection_map[] array could do without __PXXX/__SXXX macros,
> making them redundant and dropping them off.
> 
> But platforms which do not define their custom vm_get_page_prot() enabling
> ARCH_HAS_VM_GET_PAGE_PROT, will still have to provide __PXXX/__SXXX macros.
> Although this now provides a method for other willing platforms to drop off
> __PXXX/__SXX macros completely.
> 
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: x86@kernel.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linuxppc-dev@lists.ozlabs.org
> Cc: sparclinux@vger.kernel.org
> Cc: linux-mm@kvack.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
>   arch/arm64/include/asm/pgtable-prot.h | 18 ------------------
>   arch/arm64/mm/mmap.c                  | 21 +++++++++++++++++++++
>   arch/powerpc/include/asm/pgtable.h    |  2 ++
>   arch/powerpc/mm/book3s64/pgtable.c    | 20 ++++++++++++++++++++
>   arch/sparc/include/asm/pgtable_32.h   |  2 ++
>   arch/sparc/include/asm/pgtable_64.h   | 19 -------------------
>   arch/sparc/mm/init_64.c               | 20 ++++++++++++++++++++
>   arch/x86/include/asm/pgtable_types.h  | 19 -------------------
>   arch/x86/mm/pgprot.c                  | 19 +++++++++++++++++++
>   include/linux/mm.h                    |  2 ++
>   mm/mmap.c                             |  2 +-
>   11 files changed, 87 insertions(+), 57 deletions(-)
> 

> diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
> index d564d0ecd4cd..8ed2a80c896e 100644
> --- a/arch/powerpc/include/asm/pgtable.h
> +++ b/arch/powerpc/include/asm/pgtable.h
> @@ -21,6 +21,7 @@ struct mm_struct;
>   #endif /* !CONFIG_PPC_BOOK3S */
>   
>   /* Note due to the way vm flags are laid out, the bits are XWR */
> +#ifndef CONFIG_ARCH_HAS_VM_GET_PAGE_PROT

Ok, so until now it was common to all powerpc platforms. Now you define 
a different way whether it is a PPC_BOOK3S_64 or another platform ? 
What's the point ?

>   #define __P000	PAGE_NONE
>   #define __P001	PAGE_READONLY
>   #define __P010	PAGE_COPY
> @@ -38,6 +39,7 @@ struct mm_struct;
>   #define __S101	PAGE_READONLY_X
>   #define __S110	PAGE_SHARED_X
>   #define __S111	PAGE_SHARED_X
> +#endif
>   
>   #ifndef __ASSEMBLY__
>   
> diff --git a/arch/powerpc/mm/book3s64/pgtable.c b/arch/powerpc/mm/book3s64/pgtable.c
> index 7b9966402b25..2cf10a17c0a9 100644
> --- a/arch/powerpc/mm/book3s64/pgtable.c
> +++ b/arch/powerpc/mm/book3s64/pgtable.c
> @@ -551,6 +551,26 @@ unsigned long memremap_compat_align(void)
>   EXPORT_SYMBOL_GPL(memremap_compat_align);
>   #endif
>   
> +/* Note due to the way vm flags are laid out, the bits are XWR */
> +static pgprot_t protection_map[16] __ro_after_init = {

I don't think powerpc modifies that at all. Could be const instead of 
ro_after_init.

> +	[VM_NONE]					= PAGE_NONE,
> +	[VM_READ]					= PAGE_READONLY,
> +	[VM_WRITE]					= PAGE_COPY,
> +	[VM_WRITE | VM_READ]				= PAGE_COPY,
> +	[VM_EXEC]					= PAGE_READONLY_X,
> +	[VM_EXEC | VM_READ]				= PAGE_READONLY_X,
> +	[VM_EXEC | VM_WRITE]				= PAGE_COPY_X,
> +	[VM_EXEC | VM_WRITE | VM_READ]			= PAGE_COPY_X,
> +	[VM_SHARED]					= PAGE_NONE,
> +	[VM_SHARED | VM_READ]				= PAGE_READONLY,
> +	[VM_SHARED | VM_WRITE]				= PAGE_SHARED,
> +	[VM_SHARED | VM_WRITE | VM_READ]		= PAGE_SHARED,
> +	[VM_SHARED | VM_EXEC]				= PAGE_READONLY_X,
> +	[VM_SHARED | VM_EXEC | VM_READ]			= PAGE_READONLY_X,
> +	[VM_SHARED | VM_EXEC | VM_WRITE]		= PAGE_SHARED_X,
> +	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= PAGE_SHARED_X
> +};

That's nice but it could apply to all powerpc platforms. Why restrict it 
to book3s/64 ?

> +
>   pgprot_t vm_get_page_prot(unsigned long vm_flags)
>   {
>   	unsigned long prot = pgprot_val(protection_map[vm_flags &
> diff --git a/arch/sparc/include/asm/pgtable_32.h b/arch/sparc/include/asm/pgtable_32.h
> index 4866625da314..bca98b280fdd 100644
> --- a/arch/sparc/include/asm/pgtable_32.h
> +++ b/arch/sparc/include/asm/pgtable_32.h
> @@ -65,6 +65,7 @@ void paging_init(void);
>   extern unsigned long ptr_in_current_pgd;
>   
>   /*         xwr */
> +#ifndef CONFIG_ARCH_HAS_VM_GET_PAGE_PROT

CONFIG_ARCH_HAS_VM_GET_PAGE_PROT is selected by sparc64 only, is that 
ifdef needed at all ?

>   #define __P000  PAGE_NONE
>   #define __P001  PAGE_READONLY
>   #define __P010  PAGE_COPY
> @@ -82,6 +83,7 @@ extern unsigned long ptr_in_current_pgd;
>   #define __S101	PAGE_READONLY
>   #define __S110	PAGE_SHARED
>   #define __S111	PAGE_SHARED
> +#endif
>   
>   /* First physical page can be anywhere, the following is needed so that
>    * va-->pa and vice versa conversions work properly without performance
> diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
> index 4679e45c8348..a779418ceba9 100644
> --- a/arch/sparc/include/asm/pgtable_64.h
> +++ b/arch/sparc/include/asm/pgtable_64.h
> @@ -187,25 +187,6 @@ bool kern_addr_valid(unsigned long addr);
>   #define _PAGE_SZHUGE_4U	_PAGE_SZ4MB_4U
>   #define _PAGE_SZHUGE_4V	_PAGE_SZ4MB_4V
>   
> -/* These are actually filled in at boot time by sun4{u,v}_pgprot_init() */
> -#define __P000	__pgprot(0)
> -#define __P001	__pgprot(0)
> -#define __P010	__pgprot(0)
> -#define __P011	__pgprot(0)
> -#define __P100	__pgprot(0)
> -#define __P101	__pgprot(0)
> -#define __P110	__pgprot(0)
> -#define __P111	__pgprot(0)
> -
> -#define __S000	__pgprot(0)
> -#define __S001	__pgprot(0)
> -#define __S010	__pgprot(0)
> -#define __S011	__pgprot(0)
> -#define __S100	__pgprot(0)
> -#define __S101	__pgprot(0)
> -#define __S110	__pgprot(0)
> -#define __S111	__pgprot(0)
> -
>   #ifndef __ASSEMBLY__
>   
>   pte_t mk_pte_io(unsigned long, pgprot_t, int, unsigned long);
> diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
> index f6174df2d5af..6edc2a68b73c 100644
> --- a/arch/sparc/mm/init_64.c
> +++ b/arch/sparc/mm/init_64.c
> @@ -2634,6 +2634,26 @@ void vmemmap_free(unsigned long start, unsigned long end,
>   }
>   #endif /* CONFIG_SPARSEMEM_VMEMMAP */
>   
> +/* These are actually filled in at boot time by sun4{u,v}_pgprot_init() */
> +static pgprot_t protection_map[16] __ro_after_init = {
> +	[VM_NONE]					= __pgprot(0),
> +	[VM_READ]					= __pgprot(0),
> +	[VM_WRITE]					= __pgprot(0),
> +	[VM_WRITE | VM_READ]				= __pgprot(0),
> +	[VM_EXEC]					= __pgprot(0),
> +	[VM_EXEC | VM_READ]				= __pgprot(0),
> +	[VM_EXEC | VM_WRITE]				= __pgprot(0),
> +	[VM_EXEC | VM_WRITE | VM_READ]			= __pgprot(0),
> +	[VM_SHARED]					= __pgprot(0),
> +	[VM_SHARED | VM_READ]				= __pgprot(0),
> +	[VM_SHARED | VM_WRITE]				= __pgprot(0),
> +	[VM_SHARED | VM_WRITE | VM_READ]		= __pgprot(0),
> +	[VM_SHARED | VM_EXEC]				= __pgprot(0),
> +	[VM_SHARED | VM_EXEC | VM_READ]			= __pgprot(0),
> +	[VM_SHARED | VM_EXEC | VM_WRITE]		= __pgprot(0),
> +	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= __pgprot(0)
> +};

__pgprot(0) is 0 so you don't need to initialise the fields at all, it 
is zeroized at startup as part of BSS section.

> +
>   static void prot_init_common(unsigned long page_none,
>   			     unsigned long page_shared,
>   			     unsigned long page_copy,

> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index bc8f326be0ce..2254c1980c8e 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -420,11 +420,13 @@ extern unsigned int kobjsize(const void *objp);
>   #endif
>   #define VM_FLAGS_CLEAR	(ARCH_VM_PKEY_FLAGS | VM_ARCH_CLEAR)
>   
> +#ifndef CONFIG_ARCH_HAS_VM_GET_PAGE_PROT
>   /*
>    * mapping from the currently active vm_flags protection bits (the
>    * low four bits) to a page protection mask..
>    */
>   extern pgprot_t protection_map[16];
> +#endif
>   
>   /*
>    * The default fault flags that should be used by most of the
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 61e6135c54ef..e66920414945 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -101,6 +101,7 @@ static void unmap_region(struct mm_struct *mm,
>    *								w: (no) no
>    *								x: (yes) yes
>    */
> +#ifndef CONFIG_ARCH_HAS_VM_GET_PAGE_PROT
>   pgprot_t protection_map[16] __ro_after_init = {
>   	[VM_NONE]					= __P000,
>   	[VM_READ]					= __P001,
> @@ -120,7 +121,6 @@ pgprot_t protection_map[16] __ro_after_init = {
>   	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= __S111
>   };
>   
> -#ifndef CONFIG_ARCH_HAS_VM_GET_PAGE_PROT

Why not let architectures provide their protection_map[] and keep that 
function ?

>   pgprot_t vm_get_page_prot(unsigned long vm_flags)
>   {
>   	return protection_map[vm_flags & (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)];

Re: [PATCH 2/6] s390/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

[Christophe Leroy]

Le 03/06/2022 à 12:14, Anshuman Khandual a écrit :
> This defines and exports a platform specific custom vm_get_page_prot() via
> subscribing ARCH_HAS_VM_GET_PAGE_PROT. Subsequently all __SXXX and __PXXX
> macros can be dropped which are no longer needed.
> 
> Cc: Heiko Carstens <hca@linux.ibm.com>
> Cc: Vasily Gorbik <gor@linux.ibm.com>
> Cc: linux-s390@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Acked-by: Sven Schnelle <svens@linux.ibm.com>
> Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
>   arch/s390/Kconfig               |  1 +
>   arch/s390/include/asm/pgtable.h | 17 -----------------
>   arch/s390/mm/mmap.c             | 33 +++++++++++++++++++++++++++++++++
>   3 files changed, 34 insertions(+), 17 deletions(-)
> 
> diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
> index b17239ae7bd4..cdcf678deab1 100644
> --- a/arch/s390/Kconfig
> +++ b/arch/s390/Kconfig
> @@ -81,6 +81,7 @@ config S390
>   	select ARCH_HAS_SYSCALL_WRAPPER
>   	select ARCH_HAS_UBSAN_SANITIZE_ALL
>   	select ARCH_HAS_VDSO_DATA
> +	select ARCH_HAS_VM_GET_PAGE_PROT
>   	select ARCH_HAVE_NMI_SAFE_CMPXCHG
>   	select ARCH_INLINE_READ_LOCK
>   	select ARCH_INLINE_READ_LOCK_BH
> diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
> index a397b072a580..c63a05b5368a 100644
> --- a/arch/s390/include/asm/pgtable.h
> +++ b/arch/s390/include/asm/pgtable.h
> @@ -424,23 +424,6 @@ static inline int is_module_addr(void *addr)
>    * implies read permission.
>    */
>            /*xwr*/
> -#define __P000	PAGE_NONE
> -#define __P001	PAGE_RO
> -#define __P010	PAGE_RO
> -#define __P011	PAGE_RO
> -#define __P100	PAGE_RX
> -#define __P101	PAGE_RX
> -#define __P110	PAGE_RX
> -#define __P111	PAGE_RX
> -
> -#define __S000	PAGE_NONE
> -#define __S001	PAGE_RO
> -#define __S010	PAGE_RW
> -#define __S011	PAGE_RW
> -#define __S100	PAGE_RX
> -#define __S101	PAGE_RX
> -#define __S110	PAGE_RWX
> -#define __S111	PAGE_RWX
>   
>   /*
>    * Segment entry (large page) protection definitions.
> diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
> index d545f5c39f7e..11d75b8d5ec0 100644
> --- a/arch/s390/mm/mmap.c
> +++ b/arch/s390/mm/mmap.c
> @@ -188,3 +188,36 @@ void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack)
>   		mm->get_unmapped_area = arch_get_unmapped_area_topdown;
>   	}
>   }
> +
> +pgprot_t vm_get_page_prot(unsigned long vm_flags)
> +{
> +	switch (vm_flags & (VM_READ | VM_WRITE | VM_EXEC | VM_SHARED)) {
> +	case VM_NONE:
> +		return PAGE_NONE;
> +	case VM_READ:
> +	case VM_WRITE:
> +	case VM_WRITE | VM_READ:
> +		return PAGE_RO;
> +	case VM_EXEC:
> +	case VM_EXEC | VM_READ:
> +	case VM_EXEC | VM_WRITE:
> +	case VM_EXEC | VM_WRITE | VM_READ:
> +		return PAGE_RX;
> +	case VM_SHARED:
> +		return PAGE_NONE;
> +	case VM_SHARED | VM_READ:
> +		return PAGE_RO;
> +	case VM_SHARED | VM_WRITE:
> +	case VM_SHARED | VM_WRITE | VM_READ:
> +		return PAGE_RW;
> +	case VM_SHARED | VM_EXEC:
> +	case VM_SHARED | VM_EXEC | VM_READ:
> +		return PAGE_RX;
> +	case VM_SHARED | VM_EXEC | VM_WRITE:
> +	case VM_SHARED | VM_EXEC | VM_WRITE | VM_READ:
> +		return PAGE_RWX;
> +	default:
> +		BUILD_BUG();
> +	}
> +}
> +EXPORT_SYMBOL(vm_get_page_prot);

Wasn't it demonstrated in previous discussions that a switch/case is 
suboptimal compared to a table cell read ?

In order to get rid of the _Sxxx/_Pxxx macros, my preference would go to 
having architectures provide their own protection_map[] table, and keep 
the generic vm_get_page_prot() for the architectures would don't need a 
specific version of it.

This comment applies to all following patches as well.

Re: [PATCH 4/6] csky/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

[Guo Ren]

Acked-by: Guo Ren <guoren@kernel.org>

On Fri, Jun 3, 2022 at 6:15 PM Anshuman Khandual
<anshuman.khandual@arm.com> wrote:
>
> This defines and exports a platform specific custom vm_get_page_prot() via
> subscribing ARCH_HAS_VM_GET_PAGE_PROT. Subsequently all __SXXX and __PXXX
> macros can be dropped which are no longer needed.
>
> Cc: Geert Uytterhoeven <geert@linux-m68k.org>
> Cc: linux-csky@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Acked-by: Guo Ren <guoren@kernel.org>
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
>  arch/csky/Kconfig               |  1 +
>  arch/csky/include/asm/pgtable.h | 18 ------------------
>  arch/csky/mm/init.c             | 32 ++++++++++++++++++++++++++++++++
>  3 files changed, 33 insertions(+), 18 deletions(-)
>
> diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
> index 21d72b078eef..588b8a9c68ed 100644
> --- a/arch/csky/Kconfig
> +++ b/arch/csky/Kconfig
> @@ -6,6 +6,7 @@ config CSKY
>         select ARCH_HAS_GCOV_PROFILE_ALL
>         select ARCH_HAS_SYNC_DMA_FOR_CPU
>         select ARCH_HAS_SYNC_DMA_FOR_DEVICE
> +       select ARCH_HAS_VM_GET_PAGE_PROT
>         select ARCH_USE_BUILTIN_BSWAP
>         select ARCH_USE_QUEUED_RWLOCKS
>         select ARCH_WANT_FRAME_POINTERS if !CPU_CK610 && $(cc-option,-mbacktrace)
> diff --git a/arch/csky/include/asm/pgtable.h b/arch/csky/include/asm/pgtable.h
> index bbe245117777..229a5f4ad7fc 100644
> --- a/arch/csky/include/asm/pgtable.h
> +++ b/arch/csky/include/asm/pgtable.h
> @@ -77,24 +77,6 @@
>  #define MAX_SWAPFILES_CHECK() \
>                 BUILD_BUG_ON(MAX_SWAPFILES_SHIFT != 5)
>
> -#define __P000 PAGE_NONE
> -#define __P001 PAGE_READ
> -#define __P010 PAGE_READ
> -#define __P011 PAGE_READ
> -#define __P100 PAGE_READ
> -#define __P101 PAGE_READ
> -#define __P110 PAGE_READ
> -#define __P111 PAGE_READ
> -
> -#define __S000 PAGE_NONE
> -#define __S001 PAGE_READ
> -#define __S010 PAGE_WRITE
> -#define __S011 PAGE_WRITE
> -#define __S100 PAGE_READ
> -#define __S101 PAGE_READ
> -#define __S110 PAGE_WRITE
> -#define __S111 PAGE_WRITE
> -
>  extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
>  #define ZERO_PAGE(vaddr)       (virt_to_page(empty_zero_page))
>
> diff --git a/arch/csky/mm/init.c b/arch/csky/mm/init.c
> index bf2004aa811a..f9babbed17d4 100644
> --- a/arch/csky/mm/init.c
> +++ b/arch/csky/mm/init.c
> @@ -197,3 +197,35 @@ void __init fixaddr_init(void)
>         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
>         fixrange_init(vaddr, vaddr + PMD_SIZE, swapper_pg_dir);
>  }
> +
> +pgprot_t vm_get_page_prot(unsigned long vm_flags)
> +{
> +       switch (vm_flags & (VM_READ | VM_WRITE | VM_EXEC | VM_SHARED)) {
> +       case VM_NONE:
> +               return PAGE_NONE;
> +       case VM_READ:
> +       case VM_WRITE:
> +       case VM_WRITE | VM_READ:
> +       case VM_EXEC:
> +       case VM_EXEC | VM_READ:
> +       case VM_EXEC | VM_WRITE:
> +       case VM_EXEC | VM_WRITE | VM_READ:
> +               return PAGE_READ;
> +       case VM_SHARED:
> +               return PAGE_NONE;
> +       case VM_SHARED | VM_READ:
> +               return PAGE_READ;
> +       case VM_SHARED | VM_WRITE:
> +       case VM_SHARED | VM_WRITE | VM_READ:
> +               return PAGE_WRITE;
> +       case VM_SHARED | VM_EXEC:
> +       case VM_SHARED | VM_EXEC | VM_READ:
> +               return PAGE_READ;
> +       case VM_SHARED | VM_EXEC | VM_WRITE:
> +       case VM_SHARED | VM_EXEC | VM_WRITE | VM_READ:
> +               return PAGE_WRITE;
> +       default:
> +               BUILD_BUG();
> +       }
> +}
> +EXPORT_SYMBOL(vm_get_page_prot);
> --
> 2.25.1
>


-- 
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/

Re: [PATCH 6/6] openrisc/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

[Stafford Horne]

On Fri, Jun 03, 2022 at 03:44:11PM +0530, Anshuman Khandual wrote:
> This defines and exports a platform specific custom vm_get_page_prot() via
> subscribing ARCH_HAS_VM_GET_PAGE_PROT. Subsequently all __SXXX and __PXXX
> macros can be dropped which are no longer needed.
> 
> Cc: Jonas Bonn <jonas@southpole.se>
> Cc: openrisc@lists.librecores.org
> Cc: linux-kernel@vger.kernel.org
> Acked-by: Stafford Horne <shorne@gmail.com>
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>

Is it possible to retract my Acked-by?  I was following the discussion of this
new function actually being sub optimal.  So as far as I am concerned all these
architecture patches should be nak'ed.

-Stafford

Re: [PATCH 6/6] openrisc/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

[Anshuman Khandual]

On 6/5/22 11:37, Stafford Horne wrote:
> On Fri, Jun 03, 2022 at 03:44:11PM +0530, Anshuman Khandual wrote:
>> This defines and exports a platform specific custom vm_get_page_prot() via
>> subscribing ARCH_HAS_VM_GET_PAGE_PROT. Subsequently all __SXXX and __PXXX
>> macros can be dropped which are no longer needed.
>>
>> Cc: Jonas Bonn <jonas@southpole.se>
>> Cc: openrisc@lists.librecores.org
>> Cc: linux-kernel@vger.kernel.org
>> Acked-by: Stafford Horne <shorne@gmail.com>
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> 
> Is it possible to retract my Acked-by?  I was following the discussion of this
> new function actually being sub optimal.  So as far as I am concerned all these
> architecture patches should be nak'ed.

Sure, alright. I am planning to redo these arch patches via making
the protection_map[] array private to the platforms but possibly
with a common look up function as Christophe had suggested earlier.

Re: [PATCH 4/6] csky/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

[Anshuman Khandual]

On 6/4/22 17:43, Guo Ren wrote:
> Acked-by: Guo Ren <guoren@kernel.org>

I will resend this series with suggested changes.

> 
> On Fri, Jun 3, 2022 at 6:15 PM Anshuman Khandual
> <anshuman.khandual@arm.com> wrote:
>>
>> This defines and exports a platform specific custom vm_get_page_prot() via
>> subscribing ARCH_HAS_VM_GET_PAGE_PROT. Subsequently all __SXXX and __PXXX
>> macros can be dropped which are no longer needed.
>>
>> Cc: Geert Uytterhoeven <geert@linux-m68k.org>
>> Cc: linux-csky@vger.kernel.org
>> Cc: linux-kernel@vger.kernel.org
>> Acked-by: Guo Ren <guoren@kernel.org>
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
>> ---
>>  arch/csky/Kconfig               |  1 +
>>  arch/csky/include/asm/pgtable.h | 18 ------------------
>>  arch/csky/mm/init.c             | 32 ++++++++++++++++++++++++++++++++
>>  3 files changed, 33 insertions(+), 18 deletions(-)
>>
>> diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
>> index 21d72b078eef..588b8a9c68ed 100644
>> --- a/arch/csky/Kconfig
>> +++ b/arch/csky/Kconfig
>> @@ -6,6 +6,7 @@ config CSKY
>>         select ARCH_HAS_GCOV_PROFILE_ALL
>>         select ARCH_HAS_SYNC_DMA_FOR_CPU
>>         select ARCH_HAS_SYNC_DMA_FOR_DEVICE
>> +       select ARCH_HAS_VM_GET_PAGE_PROT
>>         select ARCH_USE_BUILTIN_BSWAP
>>         select ARCH_USE_QUEUED_RWLOCKS
>>         select ARCH_WANT_FRAME_POINTERS if !CPU_CK610 && $(cc-option,-mbacktrace)
>> diff --git a/arch/csky/include/asm/pgtable.h b/arch/csky/include/asm/pgtable.h
>> index bbe245117777..229a5f4ad7fc 100644
>> --- a/arch/csky/include/asm/pgtable.h
>> +++ b/arch/csky/include/asm/pgtable.h
>> @@ -77,24 +77,6 @@
>>  #define MAX_SWAPFILES_CHECK() \
>>                 BUILD_BUG_ON(MAX_SWAPFILES_SHIFT != 5)
>>
>> -#define __P000 PAGE_NONE
>> -#define __P001 PAGE_READ
>> -#define __P010 PAGE_READ
>> -#define __P011 PAGE_READ
>> -#define __P100 PAGE_READ
>> -#define __P101 PAGE_READ
>> -#define __P110 PAGE_READ
>> -#define __P111 PAGE_READ
>> -
>> -#define __S000 PAGE_NONE
>> -#define __S001 PAGE_READ
>> -#define __S010 PAGE_WRITE
>> -#define __S011 PAGE_WRITE
>> -#define __S100 PAGE_READ
>> -#define __S101 PAGE_READ
>> -#define __S110 PAGE_WRITE
>> -#define __S111 PAGE_WRITE
>> -
>>  extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
>>  #define ZERO_PAGE(vaddr)       (virt_to_page(empty_zero_page))
>>
>> diff --git a/arch/csky/mm/init.c b/arch/csky/mm/init.c
>> index bf2004aa811a..f9babbed17d4 100644
>> --- a/arch/csky/mm/init.c
>> +++ b/arch/csky/mm/init.c
>> @@ -197,3 +197,35 @@ void __init fixaddr_init(void)
>>         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
>>         fixrange_init(vaddr, vaddr + PMD_SIZE, swapper_pg_dir);
>>  }
>> +
>> +pgprot_t vm_get_page_prot(unsigned long vm_flags)
>> +{
>> +       switch (vm_flags & (VM_READ | VM_WRITE | VM_EXEC | VM_SHARED)) {
>> +       case VM_NONE:
>> +               return PAGE_NONE;
>> +       case VM_READ:
>> +       case VM_WRITE:
>> +       case VM_WRITE | VM_READ:
>> +       case VM_EXEC:
>> +       case VM_EXEC | VM_READ:
>> +       case VM_EXEC | VM_WRITE:
>> +       case VM_EXEC | VM_WRITE | VM_READ:
>> +               return PAGE_READ;
>> +       case VM_SHARED:
>> +               return PAGE_NONE;
>> +       case VM_SHARED | VM_READ:
>> +               return PAGE_READ;
>> +       case VM_SHARED | VM_WRITE:
>> +       case VM_SHARED | VM_WRITE | VM_READ:
>> +               return PAGE_WRITE;
>> +       case VM_SHARED | VM_EXEC:
>> +       case VM_SHARED | VM_EXEC | VM_READ:
>> +               return PAGE_READ;
>> +       case VM_SHARED | VM_EXEC | VM_WRITE:
>> +       case VM_SHARED | VM_EXEC | VM_WRITE | VM_READ:
>> +               return PAGE_WRITE;
>> +       default:
>> +               BUILD_BUG();
>> +       }
>> +}
>> +EXPORT_SYMBOL(vm_get_page_prot);
>> --
>> 2.25.1
>>
> 
> 

Re: [PATCH 2/6] s390/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

[Anshuman Khandual]

On 6/3/22 17:55, Christophe Leroy wrote:
> 
> 
> Le 03/06/2022 à 12:14, Anshuman Khandual a écrit :
>> This defines and exports a platform specific custom vm_get_page_prot() via
>> subscribing ARCH_HAS_VM_GET_PAGE_PROT. Subsequently all __SXXX and __PXXX
>> macros can be dropped which are no longer needed.
>>
>> Cc: Heiko Carstens <hca@linux.ibm.com>
>> Cc: Vasily Gorbik <gor@linux.ibm.com>
>> Cc: linux-s390@vger.kernel.org
>> Cc: linux-kernel@vger.kernel.org
>> Acked-by: Sven Schnelle <svens@linux.ibm.com>
>> Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
>> ---
>>   arch/s390/Kconfig               |  1 +
>>   arch/s390/include/asm/pgtable.h | 17 -----------------
>>   arch/s390/mm/mmap.c             | 33 +++++++++++++++++++++++++++++++++
>>   3 files changed, 34 insertions(+), 17 deletions(-)
>>
>> diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
>> index b17239ae7bd4..cdcf678deab1 100644
>> --- a/arch/s390/Kconfig
>> +++ b/arch/s390/Kconfig
>> @@ -81,6 +81,7 @@ config S390
>>   	select ARCH_HAS_SYSCALL_WRAPPER
>>   	select ARCH_HAS_UBSAN_SANITIZE_ALL
>>   	select ARCH_HAS_VDSO_DATA
>> +	select ARCH_HAS_VM_GET_PAGE_PROT
>>   	select ARCH_HAVE_NMI_SAFE_CMPXCHG
>>   	select ARCH_INLINE_READ_LOCK
>>   	select ARCH_INLINE_READ_LOCK_BH
>> diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
>> index a397b072a580..c63a05b5368a 100644
>> --- a/arch/s390/include/asm/pgtable.h
>> +++ b/arch/s390/include/asm/pgtable.h
>> @@ -424,23 +424,6 @@ static inline int is_module_addr(void *addr)
>>    * implies read permission.
>>    */
>>            /*xwr*/
>> -#define __P000	PAGE_NONE
>> -#define __P001	PAGE_RO
>> -#define __P010	PAGE_RO
>> -#define __P011	PAGE_RO
>> -#define __P100	PAGE_RX
>> -#define __P101	PAGE_RX
>> -#define __P110	PAGE_RX
>> -#define __P111	PAGE_RX
>> -
>> -#define __S000	PAGE_NONE
>> -#define __S001	PAGE_RO
>> -#define __S010	PAGE_RW
>> -#define __S011	PAGE_RW
>> -#define __S100	PAGE_RX
>> -#define __S101	PAGE_RX
>> -#define __S110	PAGE_RWX
>> -#define __S111	PAGE_RWX
>>   
>>   /*
>>    * Segment entry (large page) protection definitions.
>> diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
>> index d545f5c39f7e..11d75b8d5ec0 100644
>> --- a/arch/s390/mm/mmap.c
>> +++ b/arch/s390/mm/mmap.c
>> @@ -188,3 +188,36 @@ void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack)
>>   		mm->get_unmapped_area = arch_get_unmapped_area_topdown;
>>   	}
>>   }
>> +
>> +pgprot_t vm_get_page_prot(unsigned long vm_flags)
>> +{
>> +	switch (vm_flags & (VM_READ | VM_WRITE | VM_EXEC | VM_SHARED)) {
>> +	case VM_NONE:
>> +		return PAGE_NONE;
>> +	case VM_READ:
>> +	case VM_WRITE:
>> +	case VM_WRITE | VM_READ:
>> +		return PAGE_RO;
>> +	case VM_EXEC:
>> +	case VM_EXEC | VM_READ:
>> +	case VM_EXEC | VM_WRITE:
>> +	case VM_EXEC | VM_WRITE | VM_READ:
>> +		return PAGE_RX;
>> +	case VM_SHARED:
>> +		return PAGE_NONE;
>> +	case VM_SHARED | VM_READ:
>> +		return PAGE_RO;
>> +	case VM_SHARED | VM_WRITE:
>> +	case VM_SHARED | VM_WRITE | VM_READ:
>> +		return PAGE_RW;
>> +	case VM_SHARED | VM_EXEC:
>> +	case VM_SHARED | VM_EXEC | VM_READ:
>> +		return PAGE_RX;
>> +	case VM_SHARED | VM_EXEC | VM_WRITE:
>> +	case VM_SHARED | VM_EXEC | VM_WRITE | VM_READ:
>> +		return PAGE_RWX;
>> +	default:
>> +		BUILD_BUG();
>> +	}
>> +}
>> +EXPORT_SYMBOL(vm_get_page_prot);
> 
> Wasn't it demonstrated in previous discussions that a switch/case is 
> suboptimal compared to a table cell read ?

Right but all these platform patches here were acked from respective
platform folks. I assumed that they might have valued the simplicity
in switch case statements, while also dropping off the __SXXX/__PXXX
macros, which is the final objective. Looks like that assumption was
not accurate.

> 
> In order to get rid of the _Sxxx/_Pxxx macros, my preference would go to 
> having architectures provide their own protection_map[] table, and keep 
> the generic vm_get_page_prot() for the architectures would don't need a 
> specific version of it.

I will try and rework the patches as suggested.

> 
> This comment applies to all following patches as well.

Re: [PATCH 1/6] mm/mmap: Restrict generic protection_map[] array visibility

[Anshuman Khandual]

On 6/3/22 17:48, Christophe Leroy wrote:
> 
> 
> Le 03/06/2022 à 12:14, Anshuman Khandual a écrit :
>> Restrict generic protection_map[] array visibility only for platforms which
>> do not enable ARCH_HAS_VM_GET_PAGE_PROT. For other platforms that do define
>> their own vm_get_page_prot() enabling ARCH_HAS_VM_GET_PAGE_PROT, could have
>> their private static protection_map[] still implementing an array look up.
>> These private protection_map[] array could do without __PXXX/__SXXX macros,
>> making them redundant and dropping them off.
>>
>> But platforms which do not define their custom vm_get_page_prot() enabling
>> ARCH_HAS_VM_GET_PAGE_PROT, will still have to provide __PXXX/__SXXX macros.
>> Although this now provides a method for other willing platforms to drop off
>> __PXXX/__SXX macros completely.
>>
>> Cc: Catalin Marinas <catalin.marinas@arm.com>
>> Cc: Will Deacon <will@kernel.org>
>> Cc: Michael Ellerman <mpe@ellerman.id.au>
>> Cc: Paul Mackerras <paulus@samba.org>
>> Cc: "David S. Miller" <davem@davemloft.net>
>> Cc: Thomas Gleixner <tglx@linutronix.de>
>> Cc: Ingo Molnar <mingo@redhat.com>
>> Cc: Andrew Morton <akpm@linux-foundation.org>
>> Cc: x86@kernel.org
>> Cc: linux-arm-kernel@lists.infradead.org
>> Cc: linuxppc-dev@lists.ozlabs.org
>> Cc: sparclinux@vger.kernel.org
>> Cc: linux-mm@kvack.org
>> Cc: linux-kernel@vger.kernel.org
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
>> ---
>>   arch/arm64/include/asm/pgtable-prot.h | 18 ------------------
>>   arch/arm64/mm/mmap.c                  | 21 +++++++++++++++++++++
>>   arch/powerpc/include/asm/pgtable.h    |  2 ++
>>   arch/powerpc/mm/book3s64/pgtable.c    | 20 ++++++++++++++++++++
>>   arch/sparc/include/asm/pgtable_32.h   |  2 ++
>>   arch/sparc/include/asm/pgtable_64.h   | 19 -------------------
>>   arch/sparc/mm/init_64.c               | 20 ++++++++++++++++++++
>>   arch/x86/include/asm/pgtable_types.h  | 19 -------------------
>>   arch/x86/mm/pgprot.c                  | 19 +++++++++++++++++++
>>   include/linux/mm.h                    |  2 ++
>>   mm/mmap.c                             |  2 +-
>>   11 files changed, 87 insertions(+), 57 deletions(-)
>>
> 
>> diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
>> index d564d0ecd4cd..8ed2a80c896e 100644
>> --- a/arch/powerpc/include/asm/pgtable.h
>> +++ b/arch/powerpc/include/asm/pgtable.h
>> @@ -21,6 +21,7 @@ struct mm_struct;
>>   #endif /* !CONFIG_PPC_BOOK3S */
>>   
>>   /* Note due to the way vm flags are laid out, the bits are XWR */
>> +#ifndef CONFIG_ARCH_HAS_VM_GET_PAGE_PROT
> 
> Ok, so until now it was common to all powerpc platforms. Now you define 
> a different way whether it is a PPC_BOOK3S_64 or another platform ? 
> What's the point ?

On powerpc,

select ARCH_HAS_VM_GET_PAGE_PROT        if PPC_BOOK3S_64

Currently protection_map[] which requires __PXXX/__SXXX macros,
is applicable on all platforms, irrespective whether they enable
ARCH_HAS_VM_GET_PAGE_PROT or not. But because protection_map[]
is being made private for ARCH_HAS_VM_GET_PAGE_PROT enabling
platforms, they will not require __PXXX/__SXXX macros anymore.

In this case, PPC_BOOK3S_64 does not require the macros anymore,
where as other powerpc platforms will still require them as they
depend on the generic protection_map[].

> 
>>   #define __P000	PAGE_NONE
>>   #define __P001	PAGE_READONLY
>>   #define __P010	PAGE_COPY
>> @@ -38,6 +39,7 @@ struct mm_struct;
>>   #define __S101	PAGE_READONLY_X
>>   #define __S110	PAGE_SHARED_X
>>   #define __S111	PAGE_SHARED_X
>> +#endif
>>   
>>   #ifndef __ASSEMBLY__
>>   
>> diff --git a/arch/powerpc/mm/book3s64/pgtable.c b/arch/powerpc/mm/book3s64/pgtable.c
>> index 7b9966402b25..2cf10a17c0a9 100644
>> --- a/arch/powerpc/mm/book3s64/pgtable.c
>> +++ b/arch/powerpc/mm/book3s64/pgtable.c
>> @@ -551,6 +551,26 @@ unsigned long memremap_compat_align(void)
>>   EXPORT_SYMBOL_GPL(memremap_compat_align);
>>   #endif
>>   
>> +/* Note due to the way vm flags are laid out, the bits are XWR */
>> +static pgprot_t protection_map[16] __ro_after_init = {
> 
> I don't think powerpc modifies that at all. Could be const instead of 
> ro_after_init.

Sure, will change that.

> 
>> +	[VM_NONE]					= PAGE_NONE,
>> +	[VM_READ]					= PAGE_READONLY,
>> +	[VM_WRITE]					= PAGE_COPY,
>> +	[VM_WRITE | VM_READ]				= PAGE_COPY,
>> +	[VM_EXEC]					= PAGE_READONLY_X,
>> +	[VM_EXEC | VM_READ]				= PAGE_READONLY_X,
>> +	[VM_EXEC | VM_WRITE]				= PAGE_COPY_X,
>> +	[VM_EXEC | VM_WRITE | VM_READ]			= PAGE_COPY_X,
>> +	[VM_SHARED]					= PAGE_NONE,
>> +	[VM_SHARED | VM_READ]				= PAGE_READONLY,
>> +	[VM_SHARED | VM_WRITE]				= PAGE_SHARED,
>> +	[VM_SHARED | VM_WRITE | VM_READ]		= PAGE_SHARED,
>> +	[VM_SHARED | VM_EXEC]				= PAGE_READONLY_X,
>> +	[VM_SHARED | VM_EXEC | VM_READ]			= PAGE_READONLY_X,
>> +	[VM_SHARED | VM_EXEC | VM_WRITE]		= PAGE_SHARED_X,
>> +	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= PAGE_SHARED_X
>> +};
> 
> That's nice but it could apply to all powerpc platforms. Why restrict it 
> to book3s/64 ?

Because as mentioned earlier, others powerpc platforms do not
enable ARCH_HAS_VM_GET_PAGE_PROT.

> 
>> +
>>   pgprot_t vm_get_page_prot(unsigned long vm_flags)
>>   {
>>   	unsigned long prot = pgprot_val(protection_map[vm_flags &
>> diff --git a/arch/sparc/include/asm/pgtable_32.h b/arch/sparc/include/asm/pgtable_32.h
>> index 4866625da314..bca98b280fdd 100644
>> --- a/arch/sparc/include/asm/pgtable_32.h
>> +++ b/arch/sparc/include/asm/pgtable_32.h
>> @@ -65,6 +65,7 @@ void paging_init(void);
>>   extern unsigned long ptr_in_current_pgd;
>>   
>>   /*         xwr */
>> +#ifndef CONFIG_ARCH_HAS_VM_GET_PAGE_PROT
> 
> CONFIG_ARCH_HAS_VM_GET_PAGE_PROT is selected by sparc64 only, is that 
> ifdef needed at all ?

Not really necessary, but added just to tighten up.

> 
>>   #define __P000  PAGE_NONE
>>   #define __P001  PAGE_READONLY
>>   #define __P010  PAGE_COPY
>> @@ -82,6 +83,7 @@ extern unsigned long ptr_in_current_pgd;
>>   #define __S101	PAGE_READONLY
>>   #define __S110	PAGE_SHARED
>>   #define __S111	PAGE_SHARED
>> +#endif
>>   
>>   /* First physical page can be anywhere, the following is needed so that
>>    * va-->pa and vice versa conversions work properly without performance
>> diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
>> index 4679e45c8348..a779418ceba9 100644
>> --- a/arch/sparc/include/asm/pgtable_64.h
>> +++ b/arch/sparc/include/asm/pgtable_64.h
>> @@ -187,25 +187,6 @@ bool kern_addr_valid(unsigned long addr);
>>   #define _PAGE_SZHUGE_4U	_PAGE_SZ4MB_4U
>>   #define _PAGE_SZHUGE_4V	_PAGE_SZ4MB_4V
>>   
>> -/* These are actually filled in at boot time by sun4{u,v}_pgprot_init() */
>> -#define __P000	__pgprot(0)
>> -#define __P001	__pgprot(0)
>> -#define __P010	__pgprot(0)
>> -#define __P011	__pgprot(0)
>> -#define __P100	__pgprot(0)
>> -#define __P101	__pgprot(0)
>> -#define __P110	__pgprot(0)
>> -#define __P111	__pgprot(0)
>> -
>> -#define __S000	__pgprot(0)
>> -#define __S001	__pgprot(0)
>> -#define __S010	__pgprot(0)
>> -#define __S011	__pgprot(0)
>> -#define __S100	__pgprot(0)
>> -#define __S101	__pgprot(0)
>> -#define __S110	__pgprot(0)
>> -#define __S111	__pgprot(0)
>> -
>>   #ifndef __ASSEMBLY__
>>   
>>   pte_t mk_pte_io(unsigned long, pgprot_t, int, unsigned long);
>> diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
>> index f6174df2d5af..6edc2a68b73c 100644
>> --- a/arch/sparc/mm/init_64.c
>> +++ b/arch/sparc/mm/init_64.c
>> @@ -2634,6 +2634,26 @@ void vmemmap_free(unsigned long start, unsigned long end,
>>   }
>>   #endif /* CONFIG_SPARSEMEM_VMEMMAP */
>>   
>> +/* These are actually filled in at boot time by sun4{u,v}_pgprot_init() */
>> +static pgprot_t protection_map[16] __ro_after_init = {
>> +	[VM_NONE]					= __pgprot(0),
>> +	[VM_READ]					= __pgprot(0),
>> +	[VM_WRITE]					= __pgprot(0),
>> +	[VM_WRITE | VM_READ]				= __pgprot(0),
>> +	[VM_EXEC]					= __pgprot(0),
>> +	[VM_EXEC | VM_READ]				= __pgprot(0),
>> +	[VM_EXEC | VM_WRITE]				= __pgprot(0),
>> +	[VM_EXEC | VM_WRITE | VM_READ]			= __pgprot(0),
>> +	[VM_SHARED]					= __pgprot(0),
>> +	[VM_SHARED | VM_READ]				= __pgprot(0),
>> +	[VM_SHARED | VM_WRITE]				= __pgprot(0),
>> +	[VM_SHARED | VM_WRITE | VM_READ]		= __pgprot(0),
>> +	[VM_SHARED | VM_EXEC]				= __pgprot(0),
>> +	[VM_SHARED | VM_EXEC | VM_READ]			= __pgprot(0),
>> +	[VM_SHARED | VM_EXEC | VM_WRITE]		= __pgprot(0),
>> +	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= __pgprot(0)
>> +};
> 
> __pgprot(0) is 0 so you don't need to initialise the fields at all, it 
> is zeroized at startup as part of BSS section.

Sure, will change.

> 
>> +
>>   static void prot_init_common(unsigned long page_none,
>>   			     unsigned long page_shared,
>>   			     unsigned long page_copy,
> 
>> diff --git a/include/linux/mm.h b/include/linux/mm.h
>> index bc8f326be0ce..2254c1980c8e 100644
>> --- a/include/linux/mm.h
>> +++ b/include/linux/mm.h
>> @@ -420,11 +420,13 @@ extern unsigned int kobjsize(const void *objp);
>>   #endif
>>   #define VM_FLAGS_CLEAR	(ARCH_VM_PKEY_FLAGS | VM_ARCH_CLEAR)
>>   
>> +#ifndef CONFIG_ARCH_HAS_VM_GET_PAGE_PROT
>>   /*
>>    * mapping from the currently active vm_flags protection bits (the
>>    * low four bits) to a page protection mask..
>>    */
>>   extern pgprot_t protection_map[16];
>> +#endif
>>   
>>   /*
>>    * The default fault flags that should be used by most of the
>> diff --git a/mm/mmap.c b/mm/mmap.c
>> index 61e6135c54ef..e66920414945 100644
>> --- a/mm/mmap.c
>> +++ b/mm/mmap.c
>> @@ -101,6 +101,7 @@ static void unmap_region(struct mm_struct *mm,
>>    *								w: (no) no
>>    *								x: (yes) yes
>>    */
>> +#ifndef CONFIG_ARCH_HAS_VM_GET_PAGE_PROT
>>   pgprot_t protection_map[16] __ro_after_init = {
>>   	[VM_NONE]					= __P000,
>>   	[VM_READ]					= __P001,
>> @@ -120,7 +121,6 @@ pgprot_t protection_map[16] __ro_after_init = {
>>   	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= __S111
>>   };
>>   
>> -#ifndef CONFIG_ARCH_HAS_VM_GET_PAGE_PROT
> 
> Why not let architectures provide their protection_map[] and keep that 
> function ?

Just to understand this correctly.

All platforms provide their private protection_map[] array, drop __SXXX, __PXXX
macros which will not be required anymore, depend on generic vm_get_page_prot()
array look up, unless they need custom function via ARCH_HAS_VM_GET_PAGE_PROT ?

> 
>>   pgprot_t vm_get_page_prot(unsigned long vm_flags)
>>   {
>>   	return protection_map[vm_flags & (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)];