From 840532711d7299d7e937952482ec899d4622c452 Mon Sep 17 00:00:00 2001 From: Anshuman Khandual Date: Mon, 11 Jul 2022 12:35:35 +0530 Subject: [PATCH] mm/mmap: build protect protection_map[] with __P000 Patch series "mm/mmap: Drop __SXXX/__PXXX macros from across platforms", v7. __SXXX/__PXXX macros are unnecessary abstraction layer in creating the generic protection_map[] array which is used for vm_get_page_prot(). This abstraction layer can be avoided, if the platforms just define the array protection_map[] for all possible vm_flags access permission combinations and also export vm_get_page_prot() implementation. This series drops __SXXX/__PXXX macros from across platforms in the tree. First it build protects generic protection_map[] array with '#ifdef __P000' and moves it inside platforms which enable ARCH_HAS_VM_GET_PAGE_PROT. Later this build protects same array with '#ifdef ARCH_HAS_VM_GET_PAGE_PROT' and moves inside remaining platforms while enabling ARCH_HAS_VM_GET_PAGE_PROT. This adds a new macro DECLARE_VM_GET_PAGE_PROT defining the current generic vm_get_page_prot(), in order for it to be reused on platforms that do not require custom implementation. Finally, ARCH_HAS_VM_GET_PAGE_PROT can just be dropped, as all platforms now define and export vm_get_page_prot(), via looking up a private and static protection_map[] array. protection_map[] data type has been changed as 'static const' on all platforms that do not change it during boot. This patch (of 26): Build protect generic protection_map[] array with __P000, so that it can be moved inside all the platforms one after the other. Otherwise there will be build failures during this process. CONFIG_ARCH_HAS_VM_GET_PAGE_PROT cannot be used for this purpose as only certain platforms enable this config now. Link: https://lkml.kernel.org/r/20220711070600.2378316-1-anshuman.khandual@arm.com Link: https://lkml.kernel.org/r/20220711070600.2378316-2-anshuman.khandual@arm.com Signed-off-by: Anshuman Khandual Reviewed-by: Christoph Hellwig Reviewed-by: Christophe Leroy Suggested-by: Christophe Leroy Cc: Arnd Bergmann Cc: Brian Cain Cc: Catalin Marinas Cc: Christoph Hellwig Cc: Chris Zankel Cc: "David S. Miller" Cc: Dinh Nguyen Cc: Geert Uytterhoeven Cc: Guo Ren Cc: Heiko Carstens Cc: Huacai Chen Cc: Ingo Molnar Cc: "James E.J. Bottomley" Cc: Jeff Dike Cc: Jonas Bonn Cc: Michael Ellerman Cc: Michal Simek Cc: Nicholas Piggin Cc: Palmer Dabbelt Cc: Paul Mackerras Cc: Paul Walmsley Cc: Richard Henderson Cc: Rich Felker Cc: Russell King Cc: Sam Ravnborg Cc: Stafford Horne Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Cc: Vasily Gorbik Cc: Vineet Gupta Cc: WANG Xuerui Cc: Will Deacon Cc: Yoshinori Sato Signed-off-by: Andrew Morton --- include/linux/mm.h | 2 ++ mm/mmap.c | 2 ++ 2 files changed, 4 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index d4ebfc206e2b..1a435ce146a2 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -425,7 +425,9 @@ extern unsigned int kobjsize(const void *objp); * mapping from the currently active vm_flags protection bits (the * low four bits) to a page protection mask.. */ +#ifdef __P000 extern pgprot_t protection_map[16]; +#endif /* * The default fault flags that should be used by most of the diff --git a/mm/mmap.c b/mm/mmap.c index c14d7286a379..def0e03cf25c 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -101,6 +101,7 @@ static void unmap_region(struct mm_struct *mm, * w: (no) no * x: (yes) yes */ +#ifdef __P000 pgprot_t protection_map[16] __ro_after_init = { [VM_NONE] = __P000, [VM_READ] = __P001, @@ -119,6 +120,7 @@ pgprot_t protection_map[16] __ro_after_init = { [VM_SHARED | VM_EXEC | VM_WRITE] = __S110, [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = __S111 }; +#endif #ifndef CONFIG_ARCH_HAS_VM_GET_PAGE_PROT pgprot_t vm_get_page_prot(unsigned long vm_flags)