kexec: add page (#1769)

pages/linux/kexec.md

@@ -0,0 +1,19 @@
+# kexec
+
+> Directly reboot into a new kernel.
+
+- Load a new kernel:
+
+`kexec -l {{path/to/kernel}} --initrd={{path/to/initrd}} --command-line={{arguments}}`
+
+- Load a new kernel with current boot parameters:
+
+`kexec -l {{path/to/kernel}} --initrd={{path/to/initrd}} --reuse-cmdline`
+
+- Execute a currently loaded kernel:
+
+`kexec -e`
+
+- Unload current kexec target kernel:
+
+`kexec -u`