Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [PATCH v4 00/24] ILP32 for ARM64 | Date | Wed, 15 Apr 2015 00:28:09 +0200 |
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On Tuesday 14 April 2015 16:00:34 Catalin Marinas wrote: > On Tue, Apr 14, 2015 at 04:07:36PM +0200, Arnd Bergmann wrote: > > For completeness, there is yet another option, which would be to use the > > exact system call table from arm64 and do all the emulation in user space > > rather than the kernel. This would however be the least compatible with > > existing source code, so you probably don't want to do that. > > It would be great if this worked but I think we looked at it before and > it seems nice until you hit the futex stuff and robust lists (I don't > fully remember the details). Some of the structures (siginfo) would no > longer be POSIX compliant and some of them aren't only accessed via libc > to be able to create shadow copies.
Well, that may or may not be acceptable. Aarch64-ilp32 mode is a hack to enable a very special class of applications, it's not like anyone would want to run a full system for this and need POSIX compliance.
We could definitely be pragmatic and do whatever helps get the job done. That said, it diverges further from what legacy 32-bit applications expect to see, so this approach will likely make an application port harder, not easier.
Arnd
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