ARM: 9127/1: mm: Cleanup access_error()

Now the write fault check in do_page_fault() and access_error() twice,
we can cleanup access_error(), and make the fault check and vma flags set
into do_page_fault() directly, then pass the vma flags to __do_page_fault.

No functional change.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index 249db39..9a6d74f 100644 (file)
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -183,26 +183,9 @@ void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 #define VM_FAULT_BADMAP                0x010000
 #define VM_FAULT_BADACCESS     0x020000
 
-/*
- * Check that the permissions on the VMA allow for the fault which occurred.
- * If we encountered a write fault, we must have write permission, otherwise
- * we allow any permission.
- */
-static inline bool access_error(unsigned int fsr, struct vm_area_struct *vma)
-{
-       unsigned int mask = VM_ACCESS_FLAGS;
-
-       if ((fsr & FSR_WRITE) && !(fsr & FSR_CM))
-               mask = VM_WRITE;
-       if (fsr & FSR_LNX_PF)
-               mask = VM_EXEC;
-
-       return vma->vm_flags & mask ? false : true;
-}
-
 static vm_fault_t __kprobes
-__do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
-               unsigned int flags, struct pt_regs *regs)
+__do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int flags,
+               unsigned long vma_flags, struct pt_regs *regs)
 {
        struct vm_area_struct *vma = find_vma(mm, addr);
        if (unlikely(!vma))
@@ -218,10 +201,10 @@ __do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
        }
 
        /*
-        * Ok, we have a good vm_area for this
-        * memory access, so we can handle it.
+        * ok, we have a good vm_area for this memory access, check the
+        * permissions on the VMA allow for the fault which occurred.
         */
-       if (access_error(fsr, vma))
+       if (!(vma->vm_flags & vma_flags))
                return VM_FAULT_BADACCESS;
 
        return handle_mm_fault(vma, addr & PAGE_MASK, flags, regs);
@@ -234,6 +217,7 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
        int sig, code;
        vm_fault_t fault;
        unsigned int flags = FAULT_FLAG_DEFAULT;
+       unsigned long vm_flags = VM_ACCESS_FLAGS;
 
        if (kprobe_page_fault(regs, fsr))
                return 0;
@@ -252,8 +236,14 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 
        if (user_mode(regs))
                flags |= FAULT_FLAG_USER;
-       if ((fsr & FSR_WRITE) && !(fsr & FSR_CM))
+
+       if ((fsr & FSR_WRITE) && !(fsr & FSR_CM)) {
                flags |= FAULT_FLAG_WRITE;
+               vm_flags = VM_WRITE;
+       }
+
+       if (fsr & FSR_LNX_PF)
+               vm_flags = VM_EXEC;
 
        perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
 
@@ -281,7 +271,7 @@ retry:
 #endif
        }
 
-       fault = __do_page_fault(mm, addr, fsr, flags, regs);
+       fault = __do_page_fault(mm, addr, flags, vm_flags, regs);
 
        /* If we need to retry but a fatal signal is pending, handle the
         * signal first. We do not need to release the mmap_lock because