mm/vma: introduce VM_ACCESS_FLAGS

There are many places where all basic VMA access flags (read, write,
exec) are initialized or checked against as a group.  One such example
is during page fault.  Existing vma_is_accessible() wrapper already
creates the notion of VMA accessibility as a group access permissions.

Hence lets just create VM_ACCESS_FLAGS (VM_READ|VM_WRITE|VM_EXEC) which
will not only reduce code duplication but also extend the VMA
accessibility concept in general.

Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Rob Springer <rspringer@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Link: http://lkml.kernel.org/r/1583391014-8170-3-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index b598e69..2dd5c41 100644 (file)
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -189,7 +189,7 @@ void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
  */
 static inline bool access_error(unsigned int fsr, struct vm_area_struct *vma)
 {
-       unsigned int mask = VM_READ | VM_WRITE | VM_EXEC;
+       unsigned int mask = VM_ACCESS_FLAGS;
 
        if ((fsr & FSR_WRITE) && !(fsr & FSR_CM))
                mask = VM_WRITE;

diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 1027851..c9cedc0 100644 (file)
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -445,7 +445,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
        const struct fault_info *inf;
        struct mm_struct *mm = current->mm;
        vm_fault_t fault, major = 0;
-       unsigned long vm_flags = VM_READ | VM_WRITE | VM_EXEC;
+       unsigned long vm_flags = VM_ACCESS_FLAGS;
        unsigned int mm_flags = FAULT_FLAG_DEFAULT;
 
        if (kprobe_page_fault(regs, esr))

diff --git a/arch/nds32/mm/fault.c b/arch/nds32/mm/fault.c
index 0cf0c08..f331e53 100644 (file)
--- a/arch/nds32/mm/fault.c
+++ b/arch/nds32/mm/fault.c
@@ -79,7 +79,7 @@ void do_page_fault(unsigned long entry, unsigned long addr,
        struct vm_area_struct *vma;
        int si_code;
        vm_fault_t fault;
-       unsigned int mask = VM_READ | VM_WRITE | VM_EXEC;
+       unsigned int mask = VM_ACCESS_FLAGS;
        unsigned int flags = FAULT_FLAG_DEFAULT;
 
        error_code = error_code & (ITYPE_mskINST | ITYPE_mskETYPE);

diff --git a/arch/powerpc/mm/book3s64/pkeys.c b/arch/powerpc/mm/book3s64/pkeys.c
index 07527f1..1199fc2 100644 (file)
--- a/arch/powerpc/mm/book3s64/pkeys.c
+++ b/arch/powerpc/mm/book3s64/pkeys.c
@@ -315,7 +315,7 @@ int __execute_only_pkey(struct mm_struct *mm)
 static inline bool vma_is_pkey_exec_only(struct vm_area_struct *vma)
 {
        /* Do this check first since the vm_flags should be hot */
-       if ((vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC)) != VM_EXEC)
+       if ((vma->vm_flags & VM_ACCESS_FLAGS) != VM_EXEC)
                return false;
 
        return (vma_pkey(vma) == vma->vm_mm->context.execute_only_pkey);

diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index d56f677..9822a1f 100644 (file)
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -580,7 +580,7 @@ void do_dat_exception(struct pt_regs *regs)
        int access;
        vm_fault_t fault;
 
-       access = VM_READ | VM_EXEC | VM_WRITE;
+       access = VM_ACCESS_FLAGS;
        fault = do_exception(regs, access);
        if (unlikely(fault))
                do_fault_error(regs, access, fault);

diff --git a/arch/unicore32/mm/fault.c b/arch/unicore32/mm/fault.c
index a9bd08f..3022104 100644 (file)
--- a/arch/unicore32/mm/fault.c
+++ b/arch/unicore32/mm/fault.c
@@ -149,7 +149,7 @@ void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
  */
 static inline bool access_error(unsigned int fsr, struct vm_area_struct *vma)
 {
-       unsigned int mask = VM_READ | VM_WRITE | VM_EXEC;
+       unsigned int mask = VM_ACCESS_FLAGS;
 
        if (!(fsr ^ 0x12))      /* write? */
                mask = VM_WRITE;

diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c
index c6f84c0..8873ed1 100644 (file)
--- a/arch/x86/mm/pkeys.c
+++ b/arch/x86/mm/pkeys.c
@@ -63,7 +63,7 @@ int __execute_only_pkey(struct mm_struct *mm)
 static inline bool vma_is_pkey_exec_only(struct vm_area_struct *vma)
 {
        /* Do this check first since the vm_flags should be hot */
-       if ((vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC)) != VM_EXEC)
+       if ((vma->vm_flags & VM_ACCESS_FLAGS) != VM_EXEC)
                return false;
        if (vma_pkey(vma) != vma->vm_mm->context.execute_only_pkey)
                return false;

diff --git a/drivers/staging/gasket/gasket_core.c b/drivers/staging/gasket/gasket_core.c
index cd181a6..8e0575f 100644 (file)
--- a/drivers/staging/gasket/gasket_core.c
+++ b/drivers/staging/gasket/gasket_core.c
@@ -689,7 +689,7 @@ static bool gasket_mmap_has_permissions(struct gasket_dev *gasket_dev,
 
        /* Make sure that no wrong flags are set. */
        requested_permissions =
-               (vma->vm_flags & (VM_WRITE | VM_READ | VM_EXEC));
+               (vma->vm_flags & VM_ACCESS_FLAGS);
        if (requested_permissions & ~(bar_permissions)) {
                dev_dbg(gasket_dev->dev,
                        "Attempting to map a region with requested permissions 0x%x, but region has permissions 0x%x.\n",

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 33076fa..4db1522 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -369,6 +369,10 @@ extern unsigned int kobjsize(const void *objp);
 
 #define VM_STACK_FLAGS (VM_STACK | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT)
 
+/* VMA basic access permission flags */
+#define VM_ACCESS_FLAGS (VM_READ | VM_WRITE | VM_EXEC)
+
+
 /*
  * Special vmas that are non-mergable, non-mlock()able.
  */
@@ -646,7 +650,7 @@ static inline bool vma_is_foreign(struct vm_area_struct *vma)
 
 static inline bool vma_is_accessible(struct vm_area_struct *vma)
 {
-       return vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC);
+       return vma->vm_flags & VM_ACCESS_FLAGS;
 }
 
 #ifdef CONFIG_SHMEM

diff --git a/mm/mmap.c b/mm/mmap.c
index de07bbc..f609e9e 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1224,7 +1224,7 @@ static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *
        return a->vm_end == b->vm_start &&
                mpol_equal(vma_policy(a), vma_policy(b)) &&
                a->vm_file == b->vm_file &&
-               !((a->vm_flags ^ b->vm_flags) & ~(VM_READ|VM_WRITE|VM_EXEC|VM_SOFTDIRTY)) &&
+               !((a->vm_flags ^ b->vm_flags) & ~(VM_ACCESS_FLAGS | VM_SOFTDIRTY)) &&
                b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT);
 }
 

diff --git a/mm/mprotect.c b/mm/mprotect.c
index 1d823b0..494192c 100644 (file)
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -419,7 +419,7 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
         */
        if (arch_has_pfn_modify_check() &&
            (vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) &&
-           (newflags & (VM_READ|VM_WRITE|VM_EXEC)) == 0) {
+           (newflags & VM_ACCESS_FLAGS) == 0) {
                pgprot_t new_pgprot = vm_get_page_prot(newflags);
 
                error = walk_page_range(current->mm, start, end,
@@ -598,7 +598,7 @@ static int do_mprotect_pkey(unsigned long start, size_t len,
                newflags |= (vma->vm_flags & ~mask_off_old_flags);
 
                /* newflags >> 4 shift VM_MAY% in place of VM_% */
-               if ((newflags & ~(newflags >> 4)) & (VM_READ | VM_WRITE | VM_EXEC)) {
+               if ((newflags & ~(newflags >> 4)) & VM_ACCESS_FLAGS) {
                        error = -EACCES;
                        goto out;
                }