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    Subject[PATCH 5.19 1000/1157] selftests/powerpc: Fix matrix multiply assist test
    Date
    From: Rashmica Gupta <rashmica@linux.ibm.com>

    [ Upstream commit cd1e64935f79e31d666172c52c951ca97152b783 ]

    The ISA states: "when ACC[i] contains defined data, the contents of VSRs
    4×i to 4×i+3 are undefined until either a VSX Move From ACC instruction
    is used to copy the contents of ACC[i] to VSRs 4×i to 4×i+3 or some other
    instruction directly writes to one of these VSRs." We aren't doing this.

    This test only works on Power10 because the hardware implementation
    happens to map ACC0 to VSRs 0-3, but will fail on any other implementation
    that doesn't do this. So add xxmfacc between writing to the accumulator
    and accessing the VSRs.

    Fixes: 3527e1ab9a79 ("selftests/powerpc: Add matrix multiply assist (MMA) test")
    Signed-off-by: Rashmica Gupta <rashmica@linux.ibm.com>
    Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
    Link: https://lore.kernel.org/r/20220617043935.428083-1-rashmica@linux.ibm.com
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    tools/testing/selftests/powerpc/math/mma.S | 3 +++
    1 file changed, 3 insertions(+)

    diff --git a/tools/testing/selftests/powerpc/math/mma.S b/tools/testing/selftests/powerpc/math/mma.S
    index 8528c9849565..61cc88b1b26b 100644
    --- a/tools/testing/selftests/powerpc/math/mma.S
    +++ b/tools/testing/selftests/powerpc/math/mma.S
    @@ -20,6 +20,9 @@ test_mma:
    /* xvi16ger2s */
    .long 0xec042958

    + /* Deprime the accumulator - xxmfacc 0 */
    + .long 0x7c000162
    +
    /* Store result in image passed in r5 */
    stxvw4x 0,0,5
    addi 5,5,16
    --
    2.35.1


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