Re:Building a 64-bit aarch64 kernel and userspace for the Ra...
by the-dude on Saturday November 16, 2019 @11:36AM
(#21553475)
Raspbian contains a 64-bit kernel nowadays, add
arm_64bit=1
to your /boot/config.txt
You now have a 64-bit kernel with 32-bit userland.
It is unclear to me what kind of code gcc now generates with -march=native. If somebody could clear that up, would be very much appreciated ( ie, does it use 31 GPRs ).
Re:Building a 64-bit aarch64 kernel and userspace for the Ra...
by monocasa on Saturday November 16, 2019 @12:42PM
(#21553839)
If it's a 32bit userland, then you don't have access to the other GPRs. The GPR field in AArch32 instructions is a max of 4 bits, so you can only encode r0-r15.
arm_64bit=1
to your /boot/config.txt
You now have a 64-bit kernel with 32-bit userland.
It is unclear to me what kind of code gcc now generates with -march=native. If somebody could clear that up, would be very much appreciated ( ie, does it use 31 GPRs ).