On 26 August 2018 at 15:30, Martin K. Petersen <martin.petersen@xxxxxxxxxx> wrote: > > Hi Ard, > >>> However, since the dependency for "crc10dif" is already satisfied, >>> nothing is going to cause the hardware-accelerated kernel modules to >>> get loaded. >> >> This is not true. All accelerated implementations based on SIMD >> polynomial multiplication are tried to the respective CPU features >> bits. This applies to x86, power, ARM and arm64. >> >> E.g., for x86 you have >> >> alias: cpu:type:x86,ven*fam*mod*:feature:*0081* >> >> which will be matched by udev if /sys/devices/system/cpu/modalias >> contains feature 0081, and so the modules will be loaded automatically >> at boot. > > If I can avoid carrying that init callback in the block integrity code > that will definitely make me happy. However, loading crct10dif-pclmul > does not happen automatically for me. crc-t10dif is linked statically > and every user of the CRC goes through that library. So nothing ever > requests the "crct10dif" modalias and no accelerator modules are loaded. > > <fresh boot> > > # lsmod | grep crc > crc32c_intel 24576 0 > crc_ccitt 16384 1 ipv6 > > # modinfo crc32c_intel | grep cpu:type > alias: cpu:type:x86,ven*fam*mod*:feature:*0094* > > # modinfo crct10dif-pclmul | grep cpu:type > alias: cpu:type:x86,ven*fam*mod*:feature:*0081* > > # egrep -o "0081|0094" /sys/devices/system/cpu/modalias > 0081 > 0094 > > # modprobe crct10dif > # lsmod | grep crc > crct10dif_pclmul 16384 1 > crc32c_intel 24576 0 > crc_ccitt 16384 1 ipv6 > > It's interesting that crc32c_intel is loaded but libcrc32c is not. That > matches your description of how things should work. But crct10dif-pclmul > isn't loaded and neither is crc32_pclmul: > > # modprobe crc32 > # lsmod | grep crc > crc32_generic 16384 0 > crc32_pclmul 16384 0 > crc32c_intel 24576 0 > crc_ccitt 16384 1 ipv6 > That is odd. On my Ubuntu system, both crct10dif_pclmul and crc32_pclmul get loaded automatically.
