Re: [PATCH 0/5] x86: IA32 emulation cleanups

From: Ingo Molnar
Date: Wed Mar 04 2015 - 00:24:35 EST



* Brian Gerst <brgerst@xxxxxxxxx> wrote:

> This series cleans up some files in the 32-bit emulation code, by merging
> with the native 32-bit code, or in the case of the syscall audit, using the
> generic compat code that was recently added.
>
> Brian Gerst (5):
> x86: Remove compat_ni_syscall()
> x86: Merge native and compat 32-bit syscall tables
> x86: Remove sys32_vm86_warning
> x86: Use generic compat audit code
> x86: Clean up ia32/Makefile

So this series is looking pretty good to me, I've picked up #1-#3,
pending clarification on #4. I've stuck them into tip:x86/asm, because
they might interact with ongoing system call entry work.

While we are at it: CONFIG_IA32_EMULATION is a misnomer: there's
nothing 'emulated' there, it's full software and hardware support for
the 32-bit ABI. It's just an ugly (and somewhat confusing) replacement
for CONFIG_COMPAT that most other architectures are using.

So could we also get rid of CONFIG_IA32_EMULATION and change most of
its uses over to CONFIG_COMPAT et al? The only complication with that
might be that IA32_EMULATION kconfig switch hardcodes a few features
currently:

select BINFMT_ELF
select COMPAT_BINFMT_ELF
select HAVE_UID16

allowing the binfmt formats to be undefined should be OK; the uid16
dependency needs to be checked, whether it's safe to allow it to be
disabled.

Thanks,

Ingo
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