ARM: mm: Provide is_write_fault()

hulk inclusion
category: feature
bugzilla: 181005 https://gitee.com/openeuler/kernel/issues/I4EUY7

-----------------------------------------------

The function will check whether the fault is caused by a write access.
Signed-off-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NPeng Liu <liupeng256@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

arch/arm/mm/fault.c

@@ -112,6 +112,11 @@ void show_pte(const char *lvl, struct mm_struct *mm, unsigned long addr)
 { }
 #endif					/* CONFIG_MMU */
 
+static inline bool is_write_fault(unsigned int fsr)
+{
+	return (fsr & FSR_WRITE) && !(fsr & FSR_CM);
+}
+
 static void die_kernel_fault(const char *msg, struct mm_struct *mm,
 			     unsigned long addr, unsigned int fsr,
 			     struct pt_regs *regs)
@@ -274,7 +279,7 @@ 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 (is_write_fault(fsr)) {
 		flags |= FAULT_FLAG_WRITE;
 		vm_flags = VM_WRITE;
 	}