arm64/mm: Use generic __pud_free() helper in pud_free() implementation

Commit 0dd4f60 ("arm64: mm: Add support for folding PUDs at
runtime") implements specialized PUD alloc/free helpers to allow the
decision whether or not to fold PUDs to be made at runtime when the
number of paging levels is 4 or higher.

Its implementation of pud_free() is based on the generic version that
existed when the patch was first written, but in the meantime, the
freeing of a PUD has become a bit more involved, and so instead of
simply freeing the page, we should invoke the generic __pud_free() that
encapsulates whatever needs doing at this point.

This fixes a reported warning emitted by the page flags
self-diagnostics.

Reported-by: Ryan Roberts <[email protected]>
Signed-off-by: Ard Biesheuvel <[email protected]>
Tested-by: Ryan Roberts <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Catalin Marinas <[email protected]>

Author: ardbiesheuvel

arch/arm64/include/asm/pgalloc.h

@@ -60,8 +60,7 @@ static inline void pud_free(struct mm_struct *mm, pud_t *pud)
 {
 	if (!pgtable_l4_enabled())
 		return;
-	BUG_ON((unsigned long)pud & (PAGE_SIZE-1));
-	free_page((unsigned long)pud);
+	__pud_free(mm, pud);
 }
 #else
 static inline void __p4d_populate(p4d_t *p4dp, phys_addr_t pudp, p4dval_t prot)