Changes

=== Executing outside critical section ===

=== Executing outside critical section ===

This is the simplest case. Process just have <code>struct rseq</code> registered in the kernel but currently instruction pointer (IP) not inside CS.

This is the simplest case. The process has a <code>struct rseq</code> registered with the kernel, but its instruction pointer (IP) is not currently executing within an RSEQ critical section.

==== Checkpoint ====

==== Checkpoint ====

We need only to determine where the <code>struct rseq</code> is and dump its address length and signature.

CRIU only needs to locate the <code>struct rseq</code> instance and record its address, length, and signature. This information is obtained using the ptrace request <code>PTRACE_GET_RSEQ_CONFIGURATION</code> (see the <code>dump_thread_rseq</code> function).

To achieve that we use special ptrace handle <code>PTRACE_GET_RSEQ_CONFIGURATION</code> (refer to the <code>dump_thread_rseq</code> function).

==== Restore ====

==== Restore ====

We need to take data about the <code>struct rseq</code> from the image (see images/rseq.proto) and register it from the parasite context using the <code>rseq</code> syscall (take a look on <code>restore_rseq</code> in criu/pie/restorer.c)

During restore, CRIU retrieves the <code>struct rseq</code> information from the checkpoint image (see images/rseq.proto) and re-register it from the parasite context using the <code>rseq</code> syscall (see <code>restore_rseq</code> in <code>criu/pie/restorer.c</code>).

=== Executing inside critical section ===

=== Executing inside critical section ===