Messages in this thread | | | Subject | Re: [PATCH v7 5/6] powerpc/64: Make COMPAT user-selectable disabled on littleendian by default. | From | Christophe Leroy <> | Date | Tue, 3 Sep 2019 05:21:49 +0000 |
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On 09/02/2019 11:53 PM, Michael Ellerman wrote: > Segher Boessenkool <segher@kernel.crashing.org> writes: >> On Mon, Sep 02, 2019 at 12:03:12PM +1000, Michael Ellerman wrote: >>> Michal Suchanek <msuchanek@suse.de> writes: >>>> On bigendian ppc64 it is common to have 32bit legacy binaries but much >>>> less so on littleendian. >>> >>> I think the toolchain people will tell you that there is no 32-bit >>> little endian ABI defined at all, if anything works it's by accident. > ^ > v2 > >> There of course is a lot of powerpcle-* support. The ABI used for it >> on linux is the SYSV ABI, just like on BE 32-bit. > > I was talking about ELFv2, which is 64-bit only. But that was based on > me thinking we had a hard assumption in the kernel that ppc64le kernels > always expect ELFv2 userland. Looking at the code though I was wrong > about that, it looks like we will run little endian ELFv1 binaries, > though I don't think anyone is testing it. > >> There also is specific powerpcle-linux support in GCC, and in binutils, >> too. Also, config.guess/config.sub supports it. Half a year ago this >> all built fine (no, I don't test it often either). >> >> I don't think glibc supports it though, so I wonder if anyone builds an >> actual system with it? Maybe busybox or the like? >> >>> So I think we should not make this selectable, unless someone puts their >>> hand up to say they want it and are willing to test it and keep it >>> working. >> >> What about actual 32-bit LE systems? Does anyone still use those? > > Not that I've ever heard of. >
We dropped support from 32-bit LE at least with a1f3ae3fe8a1 ("powerpc/32: Use stmw/lmw for registers save/restore in asm").
Discussion about it can be found at https://patchwork.ozlabs.org/patch/899465/
Christophe
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