On Wednesday, May 04, 2016 09:58:37 AM John Blinka wrote:
> Hello, Gentooers:
> 
> I have a new Dell 17 5759 with core i5-6200U skylake cpu on which I'm
> trying to dual boot windows 10 and gentoo.  All the rest of my gentoo
> hardware is much older, so this new laptop introduces 2 technologies new to
> me: uefi and 64 bit kernels.
> 
> I installed gentoo using the x86 handbook and a recent sysrescuecd usb
> drive.  The install was unremarkable except for trying to build a 64 bit
> kernel.  No matter what I do, the kernel build fails very early with the
> message:
> 
> kernel/bounds.c:1:0 error: CPU you selected does not support x86-64
> instruction set.
> 
> Looking at bounds.c does not enlighten me.
> 
> I've tried specifying a 64 bit kernel in various ways:
> 
> setting CONFIG_64BIT=y and CONFIG_X86_64=y via make menuconfig,
> 
> make defconfig, which claims it uses an x86_64_defconfig, and sets the 2
> configuration variables above to "y",
> 
> and genkernel, which says it's getting arch-specific config.sh from
> /usr/share/genkernel/arch/x86_64/config.sh, which also sets the 2 variables
> above to "y".
> 
> So, a 64 bit sysrescuecd kernel does run on this box, and its /proc/cpuinfo
> tells me that it does indeed have a core i5-6200U cpu which, per Google,
> does support the x86-64 instruction set.   I believe I've told the kernel
> make system that I want a 64 bit kernel and that the cpu I want to run it
> on supports the x86-64 instruction set.  Not trusting my kernel config
> knowledge, I've tried letting clean kernel installations produce a 64 bit
> kernel configuration for me via make defconfig and genkernel, both of which
> appear to be attempting 64 bit configurations.  All of these attempts fail
> the same way.  I've tried all of this on gentoo-sources-4.4.6 and
> -4.1.15-r1.
> 
> Any help would be greatly appreciated.  Thanks!

You should use the AMD64 handbook, not the x86 handbook, if you're trying to 
install on x86_64 hardware.

https://wiki.gentoo.org/wiki/Handbook:AMD64

More importantly, you should be booted into a 64-bit environment. That means 
using a 64-bit live image for your initial boot, and using an amd64 stage3.

EFI has similar requirements; you'll need to be booted via EFI in the first 
place in order to set up the bootloader properly; your firmware won't make the 
necessary hardware calls available to register your bootloader if you're not 
booted in EFI mode.

HTH.

-- 
:wq