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    SubjectRe: [RFC PATCH for 4.15 14/14] Restartable sequences: Provide self-tests
    On Mon, Oct 16, 2017 at 02:00:33PM +1100, Michael Ellerman wrote:
    > Mathieu Desnoyers <mathieu.desnoyers@efficios.com> writes:
    >
    > > 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
    > > - Code infinitely looping within a critical section will eventually be
    > > interrupted.
    > > - Critical sections are interrupted by signals.
    > >
    > > "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.
    > >
    > > 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.
    > >
    > > The following rseq APIs are implemented in this helper library:
    > > - rseq_register_current_thread()/rseq_unregister_current_thread():
    > > register/unregister current thread's use of rseq,
    > > - rseq_current_cpu_raw():
    > > current CPU number,
    > > - rseq_start():
    > > beginning of a restartable sequence,
    > > - rseq_cpu_at_start():
    > > CPU number at start of restartable sequence,
    > > - rseq_finish():
    > > End of restartable sequence made of zero or more loads, completed by
    > > a word-sized store,
    > > - rseq_finish2():
    > > End of restartable sequence made of zero or more loads, one
    > > speculative word-sized store, completed by a word-sized store,
    > > - rseq_finish2_release():
    > > End of restartable sequence made of zero or more loads, one
    > > speculative word-sized store, completed by a word-sized store with
    > > release semantic,
    > > - rseq_finish_memcpy():
    > > End of restartable sequence made of zero or more loads, a
    > > speculative copy of a variable length memory region, completed by a
    > > word-sized store.
    > > - rseq_finish_memcpy_release():
    > > End of restartable sequence made of zero or more loads, a
    > > speculative copy of a variable length memory region, completed by a
    > > word-sized store with release semantic.
    > >
    > > PowerPC tests have been implemented by Boqun Feng.
    >
    > Hi Boqun,
    >

    Hello Michael,

    > I'm having trouble testing these, I get:
    >
    > ~/linus/tools/testing/selftests/cpu-opv$ ./basic_cpu_opv_test
    > Testing test_compare_eq same
    > Testing test_compare_eq different
    > Testing test_compare_ne same
    > Testing test_compare_ne different
    > Testing test_2compare_eq index
    > Testing test_2compare_ne index
    > Testing test_memcpy
    > Testing test_memcpy_u32
    > Testing test_add
    > Testing test_two_add
    > Testing test_or
    > Testing test_and
    > Testing test_xor
    > Testing test_lshift
    > Testing test_rshift
    > Testing test_cmpxchg success
    > Testing test_cmpxchg fail
    >
    > ~/linus/tools/testing/selftests/rseq$ ./basic_test
    > testing current cpu
    > testing critical section
    > testing critical section is interrupted by signal
    >
    > ~/linus/tools/testing/selftests/rseq$ ./basic_percpu_ops_test
    > ./basic_percpu_ops_test: error while loading shared libraries: R_PPC64_ADDR16_HI re10d8f10a0 for symbol `' out of range
    > ~/linus/tools/testing/selftests/rseq$ ./param_test
    > ./param_test: error while loading shared libraries: R_PPC64_ADDR16_HI re136251b48 for symbol `' out of range
    >

    I think this one is due to the same reason as:

    7998eb3dc700 ("powerpc: Fix 64 bit builds with binutils 2.24")

    I have made the fix before, but seems forgot to send it to Mathieu...

    so would this help?

    diff --git a/tools/testing/selftests/rseq/rseq-ppc.h b/tools/testing/selftests/rseq/rseq-ppc.h
    index bc78b4fd72b1..39cbabe89b0e 100644
    --- a/tools/testing/selftests/rseq/rseq-ppc.h
    +++ b/tools/testing/selftests/rseq/rseq-ppc.h
    @@ -74,7 +74,7 @@ do { \
    "lis %%r17, (3b)@highest\n\t" \
    "ori %%r17, %%r17, (3b)@higher\n\t" \
    "rldicr %%r17, %%r17, 32, 31\n\t" \
    - "oris %%r17, %%r17, (3b)@h\n\t" \
    + "oris %%r17, %%r17, (3b)@high\n\t" \
    "ori %%r17, %%r17, (3b)@l\n\t" \
    "std %%r17, 0(%[rseq_cs])\n\t" \
    RSEQ_INJECT_ASM(2) \
    Regards,
    Boqun

    >
    > Any idea what's going on with the last two? I assume you don't see that
    > in your test setup :)
    >
    > cheers

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