HMX extension

[Rot127]

We miss the HMX extension. The currently most up-to-date IDA plugin idp_hexagon supports it.

Since there is almost no public information about the extension, we could use the source of idp_hexagon to create our json files for import.

[Rot127]

To summerize from https://github.com/n-o-o-n/idp_hexagon/issues/17

logs from hexagon-sim can be used to retrieve the information needed.

• Hexagon_SDK/x.y.z.w/tools/HEXAGON_Tools/a.b.cd/Tools/target/hexagon/include/hmx_hexagon_protos.h contains intrinsics.
• For generating logs:

  @hexagon-sim --pmu_statsfile $(TARGET_DIR)/pmu.log \
            --archstring "--QDSP6_MX_PRESENT 1 --hmxdebuglvl 5 --hmxdebugfile hmx.log" \
            --mv69 --mhmx -- $(TARGET) $(ARG)

• Bit 26 in SSR register must be set to enable HMX:

  static void hmx_enable( void )
  {
    // set bit SSR[26]: 2nd Coprocessor Enable
    asm volatile(
        "r0 = ssr\n\t"
        "r0 = setbit(r0, #26)\n\t"
        "ssr = r0\n\t"
        ::: "r0"
    );
  }