Add KASLR option, make nokaslr default, refactor kernel cmdline variables

Author: gsingh93

Makefile

@@ -335,6 +335,9 @@ QEMU_KERNEL_IMAGE ?= $(KERNEL_IMAGE)
 ECHR ?= 1
 ROOT ?= /dev/vda
 RW ?= rw
+KASLR ?= 0
+
+QEMU_KERNEL_CMDLINE := selinux=0
 
 QEMU_ARGS := \
   -m $(MEM) \
@@ -351,11 +354,11 @@ ifneq ($(INITRD),)
   ifeq ($(INITRD),1)
     INITRD := $(CPIO_FILE)
   endif
-  QEMU_EXTRA_KERNEL_CMDLINE += rdinit=$(RDINIT)
+  QEMU_KERNEL_CMDLINE += rdinit=$(RDINIT)
   QEMU_ARGS += -initrd $(INITRD)
 else
   QEMU_ARGS += -drive file=$(ROOTFS),if=virtio,format=$(ROOTFS_FORMAT)
-  QEMU_EXTRA_KERNEL_CMDLINE += root=$(ROOT) $(RW)
+  QEMU_KERNEL_CMDLINE += root=$(ROOT) $(RW)
 endif
 
 ifeq ($(GDB),1)
@@ -364,9 +367,9 @@ endif
 
 ifeq ($(ARCH),x86_64)
   QEMU_BIN := qemu-system-x86_64
-  QEMU_ARGS += \
-    -cpu kvm64,+smep,+smap \
-    -append "console=ttyS0 selinux=0 kpti no5lvl $(QEMU_EXTRA_KERNEL_CMDLINE)"
+  QEMU_KERNEL_CMDLINE += console=ttyS0 kpti no5lvl
+
+  QEMU_ARGS += -cpu kvm64,+smep,+smap
 
   # We can't use KVM with GitHub Actions CI
   ifneq ($(CI),true)
@@ -375,13 +378,20 @@ ifeq ($(ARCH),x86_64)
 
 else
   QEMU_BIN := qemu-system-aarch64
+  QEMU_KERNEL_CMDLINE += console=ttyAMA0
+
   QEMU_ARGS += \
     -M virt \
     -cpu cortex-a53 \
-    -semihosting-config enable=on,target=native \
-    -append "console=ttyAMA0 selinux=0 $(QEMU_EXTRA_KERNEL_CMDLINE)"
+    -semihosting-config enable=on,target=native
 endif
 
+ifeq ($(KASLR),0)
+  QEMU_KERNEL_CMDLINE += nokaslr
+endif
+
+QEMU_ARGS += -append "$(QEMU_KERNEL_CMDLINE) $(QEMU_EXTRA_KERNEL_CMDLINE)"
+
 RUN_DEPS := $(QEMU_KERNEL_IMAGE)
 
 .PHONY: run