Arnd Bergmann <arnd@xxxxxxxx> writes: > On Sunday 22 November 2015 13:29:29 Peter Maydell wrote: >> On 21 November 2015 at 23:21, Arnd Bergmann <arnd@xxxxxxxx> wrote: >> > Regarding PJ4, it's still unclear whether that has the same >> > problem and it only reports idivt when it actually supports idiva, >> > or whether the lack of idiva support on PJ4 is instead the reason >> > why the ARM ARM was updated to have separate flags. >> >> SDIV/IDIV were originally introduced for R and M profile only >> and there the Thumb encodings of SDIV/IDIV are mandatory >> whereas the ARM ones are optional (and weren't initially >> defined at all). So if you're looking for CPUs with only the >> Thumb encodings I would try checking older R profile cores >> like the Cortex-R4. > > The question is really about Marvell Dove, MMP and Armada 370, > which are all based on PJ4 or PJ4B (CPU part : 0x581), so ARMv7-A > and report idivt support but idiva. > > There are a couple of explanations here: > > a) Marvell really implemented only idivt but not idiva > and reports it correctly, and the people from > https://groups.google.com/a/dartlang.org/forum/#!topic/reviews/9wvsJvq0YYY > just misinterpreted the flags > > b) the dartlag.org folks are correct, and it supports neither > idivt nor idiva, and the /proc/cpuinfo flag is just wrong > and requires a fixup > > c) like Krait, it actually implements both idiva and idivt but > gets the reporting wrong. It's trivial to test for someone who has one. -- Måns Rullgård mans@xxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
