ARM: allow __do_kernel_fault() to report execution of memory faults

Allow __do_kernel_fault() to detect the execution of memory, so we can
provide the same fault message as do_page_fault() would do. This is
required when we split the kernel address fault handling from the
main do_page_fault() code path.

Reviewed-by: Xie Yuanbin <xieyuanbin1@huawei.com>
Tested-by: Xie Yuanbin <xieyuanbin1@huawei.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

Author: Russell King (Oracle)

arch/arm/mm/fault.c

@@ -175,6 +175,8 @@ __do_kernel_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
 	 */
 	if (addr < PAGE_SIZE) {
 		msg = "NULL pointer dereference";
+	} else if (is_permission_fault(fsr) && fsr & FSR_LNX_PF) {
+		msg = "execution of memory";
 	} else {
 		if (is_translation_fault(fsr) &&
 		    kfence_handle_page_fault(addr, is_write_fault(fsr), regs))