Re: [PATCH] mm: Define ARCH_HAS_FIRST_USER_ADDRESS

Christophe Leroy <christophe.leroy@xxxxxxxxxx> · Wed, 14 Apr 2021 07:22:06 +0200

Le 14/04/2021 à 04:54, Anshuman Khandual a écrit :

Currently most platforms define FIRST_USER_ADDRESS as 0UL duplicating the
same code all over. Instead define a new option ARCH_HAS_FIRST_USER_ADDRESS
for those platforms which would override generic default FIRST_USER_ADDRESS
value 0UL. This makes it much cleaner with reduced code.

Cc: linux-alpha@xxxxxxxxxxxxxxx
Cc: linux-snps-arc@xxxxxxxxxxxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-csky@xxxxxxxxxxxxxxx
Cc: linux-hexagon@xxxxxxxxxxxxxxx
Cc: linux-ia64@xxxxxxxxxxxxxxx
Cc: linux-m68k@xxxxxxxxxxxxxxxxxxxx
Cc: linux-mips@xxxxxxxxxxxxxxx
Cc: openrisc@xxxxxxxxxxxxxxxxxxxx
Cc: linux-parisc@xxxxxxxxxxxxxxx
Cc: linuxppc-dev@xxxxxxxxxxxxxxxx
Cc: linux-riscv@xxxxxxxxxxxxxxxxxxx
Cc: linux-s390@xxxxxxxxxxxxxxx
Cc: linux-sh@xxxxxxxxxxxxxxx
Cc: sparclinux@xxxxxxxxxxxxxxx
Cc: linux-um@xxxxxxxxxxxxxxxxxxx
Cc: linux-xtensa@xxxxxxxxxxxxxxxx
Cc: x86@xxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
---
  arch/alpha/include/asm/pgtable.h             | 1 -
  arch/arc/include/asm/pgtable.h               | 6 ------
  arch/arm/Kconfig                             | 1 +
  arch/arm64/include/asm/pgtable.h             | 2 --
  arch/csky/include/asm/pgtable.h              | 1 -
  arch/hexagon/include/asm/pgtable.h           | 3 ---
  arch/ia64/include/asm/pgtable.h              | 1 -
  arch/m68k/include/asm/pgtable_mm.h           | 1 -
  arch/microblaze/include/asm/pgtable.h        | 2 --
  arch/mips/include/asm/pgtable-32.h           | 1 -
  arch/mips/include/asm/pgtable-64.h           | 1 -
  arch/nds32/Kconfig                           | 1 +
  arch/nios2/include/asm/pgtable.h             | 2 --
  arch/openrisc/include/asm/pgtable.h          | 1 -
  arch/parisc/include/asm/pgtable.h            | 2 --
  arch/powerpc/include/asm/book3s/pgtable.h    | 1 -
  arch/powerpc/include/asm/nohash/32/pgtable.h | 1 -
  arch/powerpc/include/asm/nohash/64/pgtable.h | 2 --
  arch/riscv/include/asm/pgtable.h             | 2 --
  arch/s390/include/asm/pgtable.h              | 2 --
  arch/sh/include/asm/pgtable.h                | 2 --
  arch/sparc/include/asm/pgtable_32.h          | 1 -
  arch/sparc/include/asm/pgtable_64.h          | 3 ---
  arch/um/include/asm/pgtable-2level.h         | 1 -
  arch/um/include/asm/pgtable-3level.h         | 1 -
  arch/x86/include/asm/pgtable_types.h         | 2 --
  arch/xtensa/include/asm/pgtable.h            | 1 -
  include/linux/mm.h                           | 4 ++++
  mm/Kconfig                                   | 4 ++++
  29 files changed, 10 insertions(+), 43 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 8ba434287387..47098ccd715e 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -46,6 +46,10 @@ extern int sysctl_page_lock_unfairness;

  

  void init_mm_internals(void);

  

+#ifndef ARCH_HAS_FIRST_USER_ADDRESS


I guess you didn't test it ..... :)

should be #ifndef CONFIG_ARCH_HAS_FIRST_USER_ADDRESS


+#define FIRST_USER_ADDRESS	0UL
+#endif


But why do we need a config option at all for that ?

Why not just:

#ifndef FIRST_USER_ADDRESS
#define FIRST_USER_ADDRESS	0UL
#endif


+
  #ifndef CONFIG_NEED_MULTIPLE_NODES	/* Don't use mapnrs, do it properly */
  extern unsigned long max_mapnr;

  

diff --git a/mm/Kconfig b/mm/Kconfig

index 24c045b24b95..373fbe377075 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -806,6 +806,10 @@ config VMAP_PFN

  

  config ARCH_USES_HIGH_VMA_FLAGS

  	bool
+
+config ARCH_HAS_FIRST_USER_ADDRESS
+	bool
+
  config ARCH_HAS_PKEYS
  	bool

  





