Commit 43957b5d authored by Anshuman Khandual's avatar Anshuman Khandual Committed by Andrew Morton
Browse files

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: default avatarAnshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Suggested-by: default avatarChristoph 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: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 84053271

include/linux/pgtable.h

+28 −0
Original line number Diff line number Diff line
@@ -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 */

mm/mmap.c

+1 −25
Original line number Diff line number Diff line
@@ -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)