Re: [PATCH v3 1/2] mm: introduce ARCH_HAS_PTE_SPECIAL

2018-04-11 Thread Michal Hocko 
On Wed 11-04-18 10:03:35, Laurent Dufour wrote:
> 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.
> 
> Suggested-by: Jerome Glisse 
> Reviewed-by: Jerome Glisse 
> Acked-by: David Rientjes 
> Signed-off-by: Laurent Dufour 

Looks good to me. I have checked x86 and the generic code and it looks
good to me. Anyway arch maintainers really have to double check this.
-- 
Michal Hocko
SUSE Labs
--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v3 1/2] mm: introduce ARCH_HAS_PTE_SPECIAL

2018-04-11 Thread Laurent Dufour 
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.

Suggested-by: Jerome Glisse 
Reviewed-by: Jerome Glisse 
Acked-by: David Rientjes 
Signed-off-by: Laurent Dufour 
---
 Documentation/features/vm/pte_special/arch-support.txt | 2 +-
 arch/arc/Kconfig   | 1 +
 arch/arc/include/asm/pgtable.h | 2 --
 arch/arm/Kconfig   | 1 +
 arch/arm/include/asm/pgtable-3level.h  | 1 -
 arch/arm64/Kconfig | 1 +
 arch/arm64/include/asm/pgtable.h   | 2 --
 arch/powerpc/Kconfig   | 1 +
 arch/powerpc/include/asm/book3s/64/pgtable.h   | 3 ---
 arch/powerpc/include/asm/pte-common.h  | 3 ---
 arch/riscv/Kconfig | 1 +
 arch/riscv/include/asm/pgtable-bits.h  | 3 ---
 arch/s390/Kconfig  | 1 +
 arch/s390/include/asm/pgtable.h| 1 -
 arch/sh/Kconfig| 1 +
 arch/sh/include/asm/pgtable.h  | 2 --
 arch/sparc/Kconfig | 1 +
 arch/sparc/include/asm/pgtable_64.h| 3 ---
 arch/x86/Kconfig   | 1 +
 arch/x86/include/asm/pgtable_types.h   | 1 -
 include/linux/pfn_t.h  | 4 ++--
 mm/Kconfig | 3 +++
 mm/gup.c   | 4 ++--
 mm/memory.c| 2 +-
 24 files changed, 18 insertions(+), 27 deletions(-)

diff --git a/Documentation/features/vm/pte_special/arch-support.txt 
b/Documentation/features/vm/pte_special/arch-support.txt
index 055004f467d2..cd05924ea875 100644
--- a/Documentation/features/vm/pte_special/arch-support.txt
+++ b/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
 #
 ---
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index d76bf4a83740..8516e2b0239a 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -44,6 +44,7 @@ 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
diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h
index 08fe33830d4b..8ec5599a0957 100644
--- a/arch/arc/include/asm/pgtable.h
+++ b/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));
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index a7f8e7f4b88f..c088c851b235 100644
--- a/arch/arm/Kconfig
+++ b/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
diff --git a/arch/arm/include/asm/pgtable-3level.h