Sigma0, the Root-Pager

Sigma0 is a special L4 server that serves as the origin for mapping memory.

It is started by Fiasco.OC on the system boot and gets full access to all userland RAM and device memory. It functions as the pager (main memory provider) for Moe and as the provider for device memory for Io. Moe and Io are trusted and usually the only applications besides Ned that get a capability for Sigma0. Memory can be requested from Sigma0 directly via an IPC, or indirectly by causing page faults and having them resolved by Sigma0.

Factory

There is only one instance of Sigma0 in an L4Re system, which is made accessible to Moe via an IPC gate capability. Using this capability, Moe can request Sigma0 to create new communication channels to itself by creating additional IPC gate capabilities. This request is done using the L4::Factory interface. This is the only kind of object that can be created by the factory in Sigma0.

List of objects that the Sigma0 Factory can create:

• Sigma0 ()
  • Use protocol id L4_PROTO_SIGMA0 for creation
  • No arguments supported

See also

Sigma0 API