Implement crashdump

crashdump is a small binary which copies the ramdump from /proc/vmcore
to /dev/hvc3 which will be backed by a file outside of the VM.

crashdump is included in a init ramdisk image, and will be executed as
the init process when a kernel panic occurs.

Bug: 237381237
Test: N/A (follow-up CL needed)
Change-Id: Iecac0b437a2f512348ee28abe8b2bf6b23640029
diff --git a/microdroid/kdump/Android.bp b/microdroid/kdump/Android.bp
index 1a8c9cc..ffbfcce 100644
--- a/microdroid/kdump/Android.bp
+++ b/microdroid/kdump/Android.bp
@@ -8,3 +8,21 @@
     srcs: ["kexec.c"],
     installable: false,
 }
+
+cc_binary {
+    name: "microdroid_crashdump",
+    stem: "crashdump",
+    srcs: ["crashdump.c"],
+    static_executable: true,
+    installable: false,
+}
+
+android_filesystem {
+    name: "microdroid_crashdump_initrd",
+    deps: ["microdroid_crashdump"],
+    dirs: [
+        "dev",
+        "proc",
+    ],
+    type: "cpio",
+}