support/testing/tests/package/test_kexec.py: new runtime test

Signed-off-by: Julien Olivain <ju.o@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

DEVELOPERS

@@ -1718,6 +1718,8 @@ F:	support/testing/tests/package/sample_python_spake2.py
 F:	support/testing/tests/package/test_gnupg2.py
 F:	support/testing/tests/package/test_highway.py
 F:	support/testing/tests/package/test_hwloc.py
+F:	support/testing/tests/package/test_kexec.py
+F:	support/testing/tests/package/test_kexec/
 F:	support/testing/tests/package/test_libjxl.py
 F:	support/testing/tests/package/test_lsof.py
 F:	support/testing/tests/package/test_ncdu.py

support/testing/tests/package/test_kexec.py

@@ -0,0 +1,93 @@
+import os
+
+import infra.basetest
+
+
+class TestKexec(infra.basetest.BRTest):
+
+    # A specific configuration is needed for using kexec:
+    # - We use Aarch64 since it is well supported for kexec,
+    # - A kernel config fragment enables all the kexec parts,
+    # - The kernel Image is installed on target filesystem to be
+    #   reloaded through kexec,
+    # - We use a ext4 rootfs image exposed as a virtio storage (rather
+    #   than cpio initrd). This avoids needing to install the initrd
+    #   inside the rootfs.
+    config = \
+        """
+        BR2_aarch64=y
+        BR2_TOOLCHAIN_EXTERNAL=y
+        BR2_TARGET_GENERIC_GETTY_PORT="ttyAMA0"
+        BR2_LINUX_KERNEL=y
+        BR2_LINUX_KERNEL_CUSTOM_VERSION=y
+        BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="6.1.15"
+        BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
+        BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="board/qemu/aarch64-virt/linux.config"
+        BR2_LINUX_KERNEL_CONFIG_FRAGMENT_FILES="{}"
+        BR2_LINUX_KERNEL_INSTALL_TARGET=y
+        BR2_LINUX_KERNEL_NEEDS_HOST_OPENSSL=y
+        BR2_PACKAGE_KEXEC=y
+        BR2_TARGET_ROOTFS_EXT2=y
+        BR2_TARGET_ROOTFS_EXT2_4=y
+        # BR2_TARGET_ROOTFS_TAR is not set
+        """.format(
+            infra.filepath("tests/package/test_kexec/linux-kexec.fragment")
+        )
+
+    def test_run(self):
+        hda = os.path.join(self.builddir, "images", "rootfs.ext4")
+        kern = os.path.join(self.builddir, "images", "Image")
+        # Notes:
+        # Sufficient memory is needed to load the kernel: having at
+        # least 512MB works. kexec could silently fail if not enough
+        # memory is present. KASLR needs to be disabled for the test:
+        # we pass "nokaslr" to kernel bootargs, and also pass
+        # "dtb-kaslr-seed=off" to qemu virt machine.
+        bootargs = ["root=/dev/vda console=ttyAMA0 nokaslr"]
+        qemu_opts = ["-M", "virt,dtb-kaslr-seed=off", "-cpu", "cortex-a57", "-m", "512M",
+                     "-drive", f"file={hda},if=virtio,format=raw"]
+        self.emulator.boot(arch="aarch64",
+                           kernel=kern,
+                           kernel_cmdline=bootargs,
+                           options=qemu_opts)
+        self.emulator.login()
+
+        # Test the program can execute
+        self.assertRunOk("kexec --version")
+
+        # Check the kexec kernel is NOT loaded:
+        self.assertRunOk("test \"$(cat /sys/kernel/kexec_loaded)\" -eq 0")
+
+        # Load the Kernel:
+        # "--append br-test" adds a dummy kernel args we'll be able to
+        # check in the second executed kernel.
+        # We use the dtb image from /sys/firmware/fdt (since we don't
+        # have the dtb file in the system)
+        self.assertRunOk("kexec -d -l --dtb=/sys/firmware/fdt --reuse-cmdline --serial=ttyAMA0 --append=br-test /boot/Image")
+
+        # Check the kexec kernel IS loaded:
+        self.assertRunOk("test \"$(cat /sys/kernel/kexec_loaded)\" -eq 1")
+
+        # Create a marker file in tmpfs which is supposed to disappear
+        # after kexec kernel restart.
+        self.assertRunOk("touch /dev/shm/br-kexec-marker")
+
+        # Execute the loaded kernel (i.e perform a kexec reboot)
+        # qemu.sendline() is used here because no exit code nor
+        # program return is expected, since kexec is like a
+        # reboot. The login is expected to be reached after the
+        # command is issued.
+        self.emulator.qemu.sendline("kexec -d -e")
+
+        # Wait for the login, and log again
+        self.emulator.login()
+
+        # Check the "br-test" dummy kernel arg is present
+        self.assertRunOk("grep br-test /proc/cmdline")
+
+        # Check the test marker file is no longer here
+        self.assertRunOk("test ! -e /dev/shm/br-kexec-marker")
+
+        # After restart, the kernel is not supposed to have a kexec
+        # loaded image:
+        self.assertRunOk("test \"$(cat /sys/kernel/kexec_loaded)\" -eq 0")

support/testing/tests/package/test_kexec/linux-kexec.fragment

@@ -0,0 +1,5 @@
+CONFIG_KEXEC=y
+CONFIG_KEXEC_FILE=y
+CONFIG_PROC_KCORE=y
+CONFIG_DEBUG_KERNEL=y
+CONFIG_KALLSYMS_ALL=y