mirror of
https://github.com/torvalds/linux.git
synced 2024-12-08 20:21:34 +00:00
faeb4e09fe
Kernel uses ARCH=powerpc for both 32-bit and 64-bit PowerPC, here adds a ppc64 variant for big endian 64-bit PowerPC, users can pass XARCH=ppc64 to test it. The powernv machine of qemu-system-ppc64 is used with powernv_be_defconfig. As the document [1] shows: PowerNV (as Non-Virtualized) is the “bare metal” platform using the OPAL firmware. It runs Linux on IBM and OpenPOWER systems and it can be used as an hypervisor OS, running KVM guests, or simply as a host OS. Notes, - differs from little endian 64-bit PowerPC, vmlinux is used instead of zImage, because big endian zImage [2] only boot on qemu with x-vof=on (added from qemu v7.0) and a fixup patch [3] for qemu v7.0.51: - since the VSX support may be disabled in kernel side, to avoid "illegal instruction" errors due to missing VSX kernel support, let's simply let compiler not generate vector/scalar (VSX) instructions via the '-mno-vsx' option. - as 'man gcc' shows, '-mmultiple' is used to generate code that uses the load multiple word instructions and the store multiple word instructions. Those instructions do not work when the processor is in little-endian mode (except PPC740/PPC750), so, we only enable it for big endian powerpc. - for big endian ppc64, as the help message from arch/powerpc/Kconfig shows, the V2 ABI is standard for 64-bit little-endian, but for big-endian it is less well tested by kernel and toolchain, so, use elfv1 as-is, no need to explicitly ask toolchain to use elfv2 here. [1]: https://qemu.readthedocs.io/en/latest/system/ppc/powernv.html [2]: https://github.com/linuxppc/issues/issues/402 [3]: https://lore.kernel.org/qemu-devel/20220504065536.3534488-1-aik@ozlabs.ru/ Suggested-by: Willy Tarreau <w@1wt.eu> Link: https://lore.kernel.org/lkml/20230722121019.GD17311@1wt.eu/ Link: https://lore.kernel.org/lkml/20230719043353.GC5331@1wt.eu/ Reviewed-by: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Zhangjin Wu <falcon@tinylab.org> Signed-off-by: Willy Tarreau <w@1wt.eu> |
||
|---|---|---|
| .. | ||
| .gitignore | ||
| Makefile | ||
| nolibc-test.c | ||