docs: update enforcement page

Signed-off-by: Kornilios Kourtis <[email protected]>

docs/content/en/docs/concepts/enforcement/_index.md

@@ -5,6 +5,32 @@ weight: 4
 description: "Documentation for Tetragon enforcement system"
 ---
 
-Tetragon allows enforcing events in the kernel inline with the operation itself.
-This describes the types of enforcmenet provided by Tetragon and concerns
-policy implementors must be aware of.
+Tetragon allows enforcing events in the kernel inline with the operation itself. This document
+describes the types of enforcement provided by Tetragon and concerns policy implementors must be
+aware of.
+
+There are two ways that Tetragon performs enforcement: overriding the return value of a function and
+sending a signal (e.g., `SIGKILL`) to the process.
+
+
+## Override return value
+
+Override the return value of a call means that the function will never be executed and, instead, a
+value (typically an error) will be returned to the caller. Generally speaking, only system calls and
+security check functions allow to change their return value in this manner. Details about how users
+can configure tracing policies to override the return value can be found in the [Override
+action]({{< ref "/docs/concepts/tracing-policy/selectors#override-action" >}}) documentation.
+
+## Signals
+
+Another type of enforcement is signals. For example, users can write a TracingPolicy (details can be
+found in the [Signal action]({{<ref "/docs/concepts/tracing-policy/selectors#signal-action" >}})
+documentation) that sends a `SIGKILL` to a process matching certain criteria and thus terminate it.
+
+In contrast with overriding the return value, sending a `SIGKILL` signal does not always stop the
+operation being performed by the process that triggered the operation. For example, a `SIGKILL` sent
+in a `write()` system call does not guarantee that the data will not be written to the file.
+However, it does ensure that the process is terminated synchronously (and any threads will be
+stopped). In some cases it may be sufficient to ensure the process is stopped and the process does
+not handle the return of the call. To ensure the operation is not completed, though, the `Signal`
+action should be combined with the `Override` action.

docs/content/en/docs/concepts/tracing-policy/selectors.md

@@ -546,6 +546,11 @@ process is spawned in the container PID namespace and is not a child of PID 1.
     - action: Sigkill
 ```
 
+{{< caution >}}
+Please consult the [Enforcement]({{<ref "/docs/concepts/enforcement" >}}) section if you plan to use
+this action for enforcement.
+{{< /caution >}}
+
 ### Signal action
 
 `Signal` action sends specified signal to current process. The signal number
@@ -583,6 +588,12 @@ The difference is to use the signal action with `SIGKILL(9)` signal.
       argSig: 9
 ```
 
+{{< caution >}}
+Please consult the [Enforcement]({{<ref "/docs/concepts/enforcement" >}}) section if you plan to use
+this action for enforcement.
+{{< /caution >}}
+
+
 ### Override action
 
 `Override` action allows to modify the return value of call. While `Sigkill`