Re: [RFC PATCH V3 00/43] rv64ilp32_abi: Build CONFIG_64BIT kernel-self with ILP32 ABI

Liam R. Howlett
2025-03-25T19:24:54Z

* David Hildenbrand <david@redhat.com> [250325 14:52]:
> On 25.03.25 13:26, Peter Zijlstra wrote:
> > On Tue, Mar 25, 2025 at 08:15:41AM -0400, guoren@kernel.org wrote:
> > > From: "Guo Ren (Alibaba DAMO Academy)" <guoren@kernel.org>
> > >
> > > Since 2001, the CONFIG_64BIT kernel has been built with the LP64 ABI,
> > > but this patchset allows the CONFIG_64BIT kernel to use an ILP32 ABI
> >
> > I'm thinking you're going to be finding a metric ton of assumptions
> > about 'unsigned long' being 64bit when 64BIT=y throughout the kernel.
> >
> > I know of a couple of places where 64BIT will result in different math
> > such that a 32bit 'unsigned long' will trivially overflow.
> >
> > Please, don't do this. This adds a significant maintenance burden on all
> > of us.
> >
>
> Fully agreed.

I would go further and say I do not want this to go in.

The open ended maintenance burden is not worth extending hardware life
of a board with 16mb of ram (If I understand your 2023 LPC slides
correctly).

Thank you,
Liam