Profiles only describe ISA features, not a complete execution environment.

A software platform is a specification for an execution environment, in which software targeted for that software platform can run.

A hardware platform is a specification for a hardware system (which can be viewed as a physical realization of an execution environment).

Both software and hardware platforms include specifications for many features beyond details of the ISA used by RISC-V harts in the platform (e.g., boot process, calling convention, behavior of environment calls, discovery mechanism, presence of certain memory-mapped hardware devices, etc.). Architecture profiles factor out ISA-specific definitions from platform definitions to allow ISA profiles to be reused across different platforms, and to be used by tools (e.g., compilers) that are common across many different platforms.

A platform can add additional constraints on top of those in a profile. For example, mandating an extension that is a standard option in the underlying profile, or constraining some implementation-specific parameter in the profile to lie within a certain range.

A platform cannot remove mandates or reduce other requirements in a profile.