Re: [RFC] Rename various 'IA32' uses in arch/x86/ code

[Brian Gerst <brgerst@gmail.com>]

On Thu, Jun 18, 2015 at 12:49 PM, Ingo Molnar <mingo@kernel.org> wrote:
>
> * H. Peter Anvin <hpa@zytor.com> wrote:
>
>> On 06/08/2015 03:24 PM, tip-bot for Ingo Molnar wrote:
>> > Commit-ID:  bace7117d3fb59a6ed7ea1aa6c8994df6a28a72a
>> > Gitweb:     http://git.kernel.org/tip/bace7117d3fb59a6ed7ea1aa6c8994df6a28a72a
>> > Author:     Ingo Molnar <mingo@kernel.org>
>> > AuthorDate: Mon, 8 Jun 2015 21:20:26 +0200
>> > Committer:  Ingo Molnar <mingo@kernel.org>
>> > CommitDate: Mon, 8 Jun 2015 23:43:38 +0200
>> >
>> > x86/asm/entry: (Re-)rename __NR_entry_INT80_compat_max to __NR_syscall_compat_max
>> >
>> > Brian Gerst noticed that I did a weird rename in the following commit:
>> >
>> >    b2502b418e63 ("x86/asm/entry: Untangle 'system_call' into two entry points: entry_SYSCALL_64 and entry_INT80_32")
>> >
>> > which renamed __NR_ia32_syscall_max to __NR_entry_INT80_compat_max.
>> >
>> > Now the original name was a misnomer, but the new one is a misnomer as well,
>> > as all the 32-bit compat syscall entry points (sysenter, syscall) share the
>> > system call table, not just the INT80 based one.
>> >
>> > Rename it to __NR_syscall_compat_max.
>> >
>>
>> The original one wasn't really a misnomer, as it referred to the ia32
>> system calls specifically, but this works too.
>
> It was a misnomer, because what are the 'ia32 system calls'? We have no Intel
> specific system calls!
>
> The term 'IA32' (Intel Architecture 32-bit) is a misnomer in many existing
> arch/x86/ symbol, function and file names, and most of them should be renamed.
>
> Some common examples, with a suggested rename target:
>
>  stack_frame_ia32               -> stack_frame_compat
>  IA32_RT_SIGFRAME_sigcontext    -> COMPAT_RT_SIGFRAME_sigcontext
>  sigcontext_ia32                -> sigcontext_compat
>  user_i387_ia32_struct          -> user_i387_compat_struct
>  TIF_IA32                       -> TIF_COMPAT
>
> and here a few 'ia32' misnomers that should be addressed not via simple renames,
> but via transformations to existing compat facilities:
>
>  CONFIG_IA32_EMULATION          -> partly eliminate, partly covert to CONFIG_COMPAT use

I think we still want a symbol for code that is exclusive to 32-bit
compatibility (like entry and signal code) to keep it separate from
X32 which also wants CONFIG_COMPAT.  If I get time this weekend I'll
get the patchset to do the separation updated to the tip branch.

>  is_ia32_task()                 -> convert to is_compat_task() use
>
> This holds for file names as well, for example:
>
>  arch/x86/ia32/                 -> arch/x86/compat/
>  arch/x86/ia32/ia32_aout.c      -> arch/x86/compat/aout.c
>  arch/x86/ia32/ia32_signal.c    -> arch/x86/compat/signal.c
>  arch/x86/ia32/sys_ia32.c       -> arch/x86/compat/sys.c
>
> There are a number of symbols where the 'IA32' name is probably fine: for example
> the various Intel-specific MSR names - or even cross-CPU MSR names that AMD uses
> but which got first introduced on Intel CPUs.
>
> For generic names that deal with 32-bit compat, 'ia32' is a misnomer.
>
> If there's consensus for the above (re-)naming schemes I can start doing them.

As long as there is no confusion between this and X32, I am fine with it.

--
Brian Gerst