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

From: Sandipan Das <[email-masked]>
Date: Mon, 4 Feb 2019 09:48:34 +0530

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.

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