Re: [PATCH v7 0/4] rust: Add safe pointer formatting support

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Tue, Dec 30, 2025 at 10:03:17AM +0800, Ke Sun wrote:
> On Mon, Dec 29, 2025 at 10:12 PM Andy Shevchenko
> <andriy.shevchenko@linux.intel.com> wrote:
> >
> > On Mon, Dec 29, 2025 at 03:21:18PM +0800, Ke Sun wrote:
> > > This patch series adds safe pointer formatting support for Rust kernel code,
> > > providing three pointer wrapper types (HashedPtr, RawPtr, RestrictedPtr) that
> > > correspond to C kernel's printk format specifiers %p, %px, and %pK.
> >
> > I didn't get the motivation behind %pK. Also what's about all the extensions
> > we (currently) have?
> 
> I'm implementing a R4L wrapper for the RTC driver and currently only
> need basic pointer printing. %pK is typically used in seqfile to
> export information to userspace.
> 
> All extensions can be implemented by modifying and exporting the
> corresponding functions in C, then adding wrapper types in Rust.
> What's your recommendation on which extensions to prioritize, or
> should we implement them all?

I have no priority list, I just asked for clarification of your roadmap and %pK
case as the latter is quite rare (3 in Documentation, 8 in tools, and 25 otherwise)
and probably shouldn't have existed at all. So, I would rather not advertise it,
may be even mark as deprecated or so on Rust level.

> > > The implementation ensures that raw pointers are automatically hashed when
> > > formatted with {:p}, providing safe default behavior that prevents information
> > > leaks about kernel memory layout. Users can also explicitly use wrapper types
> > > when they need specific formatting behavior.

-- 
With Best Regards,
Andy Shevchenko