On 11/23, Arnd Bergmann wrote: > On Monday 23 November 2015 09:14:39 Christopher Covington wrote: > > On 11/23/2015 03:15 AM, Arnd Bergmann wrote: > > > On Sunday 22 November 2015 21:36:45 Nicolas Pitre wrote: > > >> On Sun, 22 Nov 2015, Arnd Bergmann wrote: > > > > > > Ok, thanks a lot! So the reporting in /proc/cpuinfo clearly matches > > > the actual features, and we can just treat this as no LPAE / no IDIV > > > for kernel compilation, as nobody ever seems to use THUMB2_KERNEL > > > in practice. > > > > > > PJ4-MP is like Cortex-A15/A7/A12/A17 and supports both IDIV and LPAE, > > > which leaves the question whether Scorpion or Krait do the same as > > > well, or whether they are outliers and need a special configuration. > > > > LPAE is only supported in the Krait 450. > > > > http://www.anandtech.com/show/7537/qualcomms-snapdragon-805-25ghz-128bit-memory-interface-d3d11class-graphics-more > > > > I'm pretty sure idiv support came earlier, but I don't have the > > specifics on hand. > > I have seen that article, but didn't trust it as a canonical > source of information here. > > If you can confirm that it's right, that would mean that we > don't support LPAE on mach-qcom, as the only SoC with Krait 450 > seems to be APQ8084, and mainline Linux doesn't run on that. arch/arm/boot/dts/qcom-apq8084.dtsi exists in the mainline kernel. We support more than what's in the Kconfig language under mach-qcom. And yes LPAE is supported by apq8084 (as is IDIV). Here's the /proc/cpuinfo on that device. # cat /proc/cpuinfo processor : 0 model name : ARMv7 Processor rev 1 (v7l) BogoMIPS : 38.40 Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae evtstrm CPU implementer : 0x51 CPU architecture: 7 CPU variant : 0x3 CPU part : 0x06f CPU revision : 1 processor : 1 model name : ARMv7 Processor rev 1 (v7l) BogoMIPS : 38.40 Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae evtstrm CPU implementer : 0x51 CPU architecture: 7 CPU variant : 0x3 CPU part : 0x06f CPU revision : 1 processor : 2 model name : ARMv7 Processor rev 1 (v7l) BogoMIPS : 38.40 Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae evtstrm CPU implementer : 0x51 CPU architecture: 7 CPU variant : 0x3 CPU part : 0x06f CPU revision : 1 processor : 3 model name : ARMv7 Processor rev 1 (v7l) BogoMIPS : 38.40 Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae evtstrm CPU implementer : 0x51 CPU architecture: 7 CPU variant : 0x3 CPU part : 0x06f CPU revision : 1 Hardware : Qualcomm (Flattened Device Tree) Revision : 0000 Serial : 0000000000000000 > > The ones we do support are MSM8x60 (Scorpion), MSM8960 > (Krait-without-number),and MSM7874 (Krait 400). Do those all > support IDIV but not LPAE? > Krait supports IDIV for all versions. Scorpion doesn't support IDIV or lpae. Here's the output of /proc/cpuinfo on that device. # cat /proc/cpuinfo processor : 0 model name : ARMv7 Processor rev 2 (v7l) BogoMIPS : 13.50 Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpd32 CPU implementer : 0x51 CPU architecture: 7 CPU variant : 0x0 CPU part : 0x02d CPU revision : 2 processor : 1 model name : ARMv7 Processor rev 2 (v7l) BogoMIPS : 13.50 Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpd32 CPU implementer : 0x51 CPU architecture: 7 CPU variant : 0x0 CPU part : 0x02d CPU revision : 2 Hardware : Qualcomm (Flattened Device Tree) Revision : 0000 Serial : 0000000000000000 -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project -- 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
