On Wed, May 29, 2024 at 09:58:35AM +0000, Christophe Leroy wrote:
 

Yes I now have :

+#define _PAGE_HSIZE_MSK (_PAGE_U0 | _PAGE_U1 | _PAGE_U2 | _PAGE_U3)
+#define _PAGE_HSIZE_SHIFT              14
+#define _PAGE_HSIZE_SHIFT_OFFSET       20

and have added a helper to avoid doing the calculation at several places:

+static inline unsigned long pte_huge_size(pte_t pte)
+{
+       pte_basic_t val = pte_val(pte);
+
+       return 1UL << (((val & _PAGE_HSIZE_MSK) >> _PAGE_HSIZE_SHIFT) + 
_PAGE_HSIZE_SHIFT_OFFSET);
+}

Great, this looks much better.

That's what I did before but it didn't work. The problem is that 
pte_advance_pfn() takes a long not a long long:

static inline pte_t pte_advance_pfn(pte_t pte, unsigned long nr)
{
	return __pte(pte_val(pte) + (nr << PFN_PTE_SHIFT));
}

And when I called it with nr = PMD_SIZE / PAGE_SIZE = 2M / 4k = 512, as 
we have PFN_PTE_SHIFT = 24, I got 512 << 24 = 0

Ah, I missed that trickery with the types.

Thanks!


-- 
Oscar Salvador
SUSE Labs