mm/mmap: define DECLARE_VM_GET_PAGE_PROT

This just converts the generic vm_get_page_prot() implementation into a
new macro i.e DECLARE_VM_GET_PAGE_PROT which later can be used across
platforms when enabling them with ARCH_HAS_VM_GET_PAGE_PROT.  This does
not create any functional change.

Link: https://lkml.kernel.org/r/20220711070600.2378316-3-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Suggested-by: Christoph Hellwig <hch@infradead.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Brian Cain <bcain@quicinc.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 3cdc16c..014ee8f 100644 (file)
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1689,4 +1689,32 @@ typedef unsigned int pgtbl_mod_mask;
 #define MAX_PTRS_PER_P4D PTRS_PER_P4D
 #endif
 
+/* description of effects of mapping type and prot in current implementation.
+ * this is due to the limited x86 page protection hardware.  The expected
+ * behavior is in parens:
+ *
+ * map_type    prot
+ *             PROT_NONE       PROT_READ       PROT_WRITE      PROT_EXEC
+ * MAP_SHARED  r: (no) no      r: (yes) yes    r: (no) yes     r: (no) yes
+ *             w: (no) no      w: (no) no      w: (yes) yes    w: (no) no
+ *             x: (no) no      x: (no) yes     x: (no) yes     x: (yes) yes
+ *
+ * MAP_PRIVATE r: (no) no      r: (yes) yes    r: (no) yes     r: (no) yes
+ *             w: (no) no      w: (no) no      w: (copy) copy  w: (no) no
+ *             x: (no) no      x: (no) yes     x: (no) yes     x: (yes) yes
+ *
+ * On arm64, PROT_EXEC has the following behaviour for both MAP_SHARED and
+ * MAP_PRIVATE (with Enhanced PAN supported):
+ *                                                             r: (no) no
+ *                                                             w: (no) no
+ *                                                             x: (yes) yes
+ */
+#define DECLARE_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)];    \
+}                                                                      \
+EXPORT_SYMBOL(vm_get_page_prot);
+
 #endif /* _LINUX_PGTABLE_H */

diff --git a/mm/mmap.c b/mm/mmap.c
index def0e03..3c0d657 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -81,26 +81,6 @@ static void unmap_region(struct mm_struct *mm,
                struct vm_area_struct *vma, struct vm_area_struct *prev,
                unsigned long start, unsigned long end);
 
-/* description of effects of mapping type and prot in current implementation.
- * this is due to the limited x86 page protection hardware.  The expected
- * behavior is in parens:
- *
- * map_type    prot
- *             PROT_NONE       PROT_READ       PROT_WRITE      PROT_EXEC
- * MAP_SHARED  r: (no) no      r: (yes) yes    r: (no) yes     r: (no) yes
- *             w: (no) no      w: (no) no      w: (yes) yes    w: (no) no
- *             x: (no) no      x: (no) yes     x: (no) yes     x: (yes) yes
- *
- * MAP_PRIVATE r: (no) no      r: (yes) yes    r: (no) yes     r: (no) yes
- *             w: (no) no      w: (no) no      w: (copy) copy  w: (no) no
- *             x: (no) no      x: (no) yes     x: (no) yes     x: (yes) yes
- *
- * On arm64, PROT_EXEC has the following behaviour for both MAP_SHARED and
- * MAP_PRIVATE (with Enhanced PAN supported):
- *                                                             r: (no) no
- *                                                             w: (no) no
- *                                                             x: (yes) yes
- */
 #ifdef __P000
 pgprot_t protection_map[16] __ro_after_init = {
        [VM_NONE]                                       = __P000,
@@ -123,11 +103,7 @@ pgprot_t protection_map[16] __ro_after_init = {
 #endif
 
 #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)];
-}
-EXPORT_SYMBOL(vm_get_page_prot);
+DECLARE_VM_GET_PAGE_PROT
 #endif /* CONFIG_ARCH_HAS_VM_GET_PAGE_PROT */
 
 static pgprot_t vm_pgprot_modify(pgprot_t oldprot, unsigned long vm_flags)