On 16.06.2023 22:27, Andrew Cooper wrote: > On 16/06/2023 6:48 pm, Shawn Anastasio wrote: >> diff --git a/xen/arch/ppc/ppc64/head.S b/xen/arch/ppc/ppc64/head.S >> new file mode 100644 >> index 0000000000..0b289c713a >> --- /dev/null >> +++ b/xen/arch/ppc/ppc64/head.S >> @@ -0,0 +1,27 @@ >> +/* SPDX-License-Identifier: GPL-2.0-or-later */ >> + >> +.section .text.header, "ax", %progbits >> + >> +ENTRY(start) >> + /* >> + * Depending on how we were booted, the CPU could be running in either >> + * Little Endian or Big Endian mode. The following trampoline from Linux >> + * cleverly uses an instruction that encodes to a NOP if the CPU's >> + * endianness matches the assumption of the assembler (LE, in our case) >> + * or a branch to code that performs the endian switch in the other >> case. >> + */ > > Sorry, I also meant to ask. How prevalent is Big Endian in practice in > the Power world? > > It's another area (like 4k pages) where I expect there to be plenty of > fun to be had with the codebase.
Why? I'd expect "fun" if ppc was meaning to run in big-endian mode. Jan
