[RFC V2 6/6] mm: Drop pxd_ERROR()

[Anshuman Khandual]

On Wed, Aug 12, 2026 at 01:33:14PM +0200, David Hildenbrand (Arm) wrote:
> On 8/11/26 06:21, Anshuman Khandual wrote:
> > pxd_ERROR() has been used in generic mm just to print the page table entry
> > in pxd_clear_bad() before clearing those out with pxd_clear() later. These
> > pxd_ERROR() macros have been provided by all platforms which basically did
> > the same thing.
> > 
> > Make pxd_clear_bad() use recently added ptval_to_str() instead for printing
> > page table entries thus completely dropping dependency on platform provided
> > pxd_ERROR() macros which can then be dropped off. First move all required
> > helpers in core MM into a header file which could then be used else where.
> > 
> 
> It might make sense to split this patch further up to ease review:
> 
> Patch 1) provide ptval_to_str() a header.
> 
> Patch 2) Stop using pxd_ERROR() and friends in common code, converting to
> pteval_to_str()
> 
> Patch 3) Remove now unused pxd_ERROR() and friends from arch code.

Sure but the intiial platform changes which now use ptval_to_str() as well
will probably come after the Patch (2) but before the Patch (3).

> 
> ...
> > +static inline void
> > +ptval_bytes_to_hex_str(char *buf, size_t buf_size, const void *entry, size_t entry_size)
> > +{
> > +	if (WARN_ON_ONCE(buf_size < entry_size * 2 + 1)) {
> > +		snprintf(buf, buf_size, "overflow");
> > +		return;
> > +	}
> > +
> > +	switch (entry_size) {
> > +	case sizeof(u32):
> > +		snprintf(buf, buf_size, "%08x", *(const u32 *)entry);
> > +		break;
> > +	case sizeof(u64):
> > +		snprintf(buf, buf_size, "%016llx", *(const u64 *)entry);
> > +		break;
> > +#if defined(__SIZEOF_INT128__)
> > +	case sizeof(u128):
> > +		snprintf(buf, buf_size, "%016llx%016llx",
> > +			 (unsigned long long)(*(const u128 *)entry >> 64),
> > +			 (unsigned long long)*(const u128 *)entry);
> > +		break;
> > +#endif
> > +	default:
> > +		snprintf(buf, buf_size, "unsupported");
> > +		break;
> > +	}
> > +}
> 
> Why not leave ptval_bytes_to_hex_str() in the C file for less churn for now?

Agreed - will change.

> 
> -- 
> Cheers,
> 
> David

Thanks for the review.