Re: [RFC PATCH 0/5] powerpc: sstep: Emulation test infrastructure

[Daniel Axtens <dja@axtens.net>]

Hi Sandipan,

> This aims to add a test infrastructure for the in-kernel instruction
> emulation code. This is currently limited to testing only the basic
> integer operations and supports verification of the GPRs, LR, XER and
> CR.
>
> There can be multiple test cases for each instruction. Each test case
> has to be provided with the initial register state (in the form of a
> struct pt_regs) and the 32-bit instruction to test.
>
> Apart from verifying the end result, problems with the behaviour of
> certain instructions for things like setting certain bits in CR or
> XER (which can also be processor dependent) can be identified.
> For example, the newly introduced CA32 bit in XER, exclusive to P9
> CPUs as of now, was not being set when expected for some of the
> arithmetic and shift instructions. With this infrastructure, it will
> be easier to identify such problems and rectify them. The test cases
> for the addc[.] instruction demonstrate this for different scenarios
> where the CA and CA32 bits of XER should be set.
>

I forgot to mention this in my other emails - I think this is a really
good idea, thank you for doing it.

Regards,
Daniel

> Sandipan Das (5):
>   powerpc: Add bitmasks for D-form instruction fields
>   powerpc: Add bitmask for Rc instruction field
>   powerpc: sstep: Add instruction emulation selftests
>   powerpc: sstep: Add selftests for add[.] instruction
>   powerpc: sstep: Add selftests for addc[.] instruction
>
>  arch/powerpc/Kconfig.debug            |   5 +
>  arch/powerpc/include/asm/ppc-opcode.h |   5 +
>  arch/powerpc/lib/Makefile             |   1 +
>  arch/powerpc/lib/exec_test_instr.S    | 150 +++++++
>  arch/powerpc/lib/sstep_tests.c        | 564 ++++++++++++++++++++++++++
>  5 files changed, 725 insertions(+)
>  create mode 100644 arch/powerpc/lib/exec_test_instr.S
>  create mode 100644 arch/powerpc/lib/sstep_tests.c
>
> -- 
> 2.19.2