On 6/24/22 10:48, Christophe Leroy wrote:

Le 24/06/2022 à 06:43, Anshuman Khandual a écrit :

quoted

This moves protection_map[] inside the platform and while here, also enable
ARCH_HAS_VM_GET_PAGE_PROT on 32 bit platforms via DECLARE_VM_GET_PAGE_PROT.

Not only 32 bit platforms, also nohash 64 (aka book3e/64)

Sure, will update the commit message.

quoted

Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <redacted>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <redacted>
---
  arch/powerpc/Kconfig               |  2 +-
  arch/powerpc/include/asm/pgtable.h | 20 +-------------------
  arch/powerpc/mm/pgtable.c          | 24 ++++++++++++++++++++++++
  3 files changed, 26 insertions(+), 20 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index c2ce2e60c8f0..1035d172c7dd 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig

@@ -140,7 +140,7 @@ config PPC
  	select ARCH_HAS_TICK_BROADCAST		if GENERIC_CLOCKEVENTS_BROADCAST
  	select ARCH_HAS_UACCESS_FLUSHCACHE
  	select ARCH_HAS_UBSAN_SANITIZE_ALL
-	select ARCH_HAS_VM_GET_PAGE_PROT	if PPC_BOOK3S_64
+	select ARCH_HAS_VM_GET_PAGE_PROT
  	select ARCH_HAVE_NMI_SAFE_CMPXCHG
  	select ARCH_KEEP_MEMBLOCK
  	select ARCH_MIGHT_HAVE_PC_PARPORT

diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
index d564d0ecd4cd..bf98db844579 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h

@@ -20,25 +20,6 @@ struct mm_struct;
  #include <asm/nohash/pgtable.h>
  #endif /* !CONFIG_PPC_BOOK3S */
  
-/* Note due to the way vm flags are laid out, the bits are XWR */
-#define __P000	PAGE_NONE
-#define __P001	PAGE_READONLY
-#define __P010	PAGE_COPY
-#define __P011	PAGE_COPY
-#define __P100	PAGE_READONLY_X
-#define __P101	PAGE_READONLY_X
-#define __P110	PAGE_COPY_X
-#define __P111	PAGE_COPY_X
-
-#define __S000	PAGE_NONE
-#define __S001	PAGE_READONLY
-#define __S010	PAGE_SHARED
-#define __S011	PAGE_SHARED
-#define __S100	PAGE_READONLY_X
-#define __S101	PAGE_READONLY_X
-#define __S110	PAGE_SHARED_X
-#define __S111	PAGE_SHARED_X
-
  #ifndef __ASSEMBLY__
  
  #ifndef MAX_PTRS_PER_PGD

@@ -79,6 +60,7 @@ extern void paging_init(void);
  void poking_init(void);
  
  extern unsigned long ioremap_bot;
+extern pgprot_t protection_map[16] __ro_after_init;
  
  /*
   * kern_addr_valid is intended to indicate whether an address is a valid

diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c
index e6166b71d36d..618f30d35b17 100644
--- a/arch/powerpc/mm/pgtable.c
+++ b/arch/powerpc/mm/pgtable.c

@@ -472,3 +472,27 @@ pte_t *__find_linux_pte(pgd_t *pgdir, unsigned long ea,
  	return ret_pte;
  }
  EXPORT_SYMBOL_GPL(__find_linux_pte);
+
+/* Note due to the way vm flags are laid out, the bits are XWR */
+pgprot_t protection_map[16] __ro_after_init = {

I can't see any place where protection_map[] gets modified. This could 
be made const.

Sure, will make it a const as in case for many other platforms as well.

quoted

+	[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
+};
+
+#ifndef CONFIG_PPC_BOOK3S_64
+DECLARE_VM_GET_PAGE_PROT
+#endif