Re: [RFC PATCH for 4.15 v3 15/22] rseq: selftests: Provide self-tests

From: Peter Zijlstra
Date: Wed Nov 22 2017 - 14:41:05 EST

On Tue, Nov 21, 2017 at 09:18:53AM -0500, Mathieu Desnoyers wrote:
> Implements two basic tests of RSEQ functionality, and one more
> exhaustive parameterizable test.
> The first, "basic_test" only asserts that RSEQ works moderately
> correctly. E.g. that the CPUID pointer works.
> "basic_percpu_ops_test" is a slightly more "realistic" variant,
> implementing a few simple per-cpu operations and testing their
> correctness.
> "param_test" is a parametrizable restartable sequences test. See
> the "--help" output for usage.
> A script runs many variants of the parametrizable
> tests.
> As part of those tests, a helper library "rseq" implements a user-space
> API around restartable sequences. It uses the cpu_opv system call as
> fallback when single-stepped by a debugger. It exposes the instruction
> pointer addresses where the rseq assembly blocks begin and end, as well
> as the associated abort instruction pointer, in the __rseq_table
> section. This section allows debuggers may know where to place
> breakpoints when single-stepping through assembly blocks which may be
> aborted at any point by the kernel.

Could I ask you to split this in smaller bits?

I'd start with just the rseq library, using only the rseq interface.
Then add the whole cpu_opv fallback stuff.
Then add the selftests using librseq.

As is this is a tad much to read in a single go.