static inline void pud_clear(pud_t *pudp)
{
+ unsigned long pgd;
+
set_pud(pudp, __pud(0));
/*
- * Pentium-II erratum A13: in PAE mode we explicitly have to flush
- * the TLB via cr3 if the top-level pgd is changed...
+ * According to Intel App note "TLBs, Paging-Structure Caches,
+ * and Their Invalidation", April 2007, document 317080-001,
+ * section 8.1: in PAE mode we explicitly have to flush the
+ * TLB via cr3 if the top-level pgd is changed...
*
- * XXX I don't think we need to worry about this here, since
- * when clearing the pud, the calling code needs to flush the
- * tlb anyway. But do it now for safety's sake. - jsgf
+ * Make sure the pud entry we're updating is within the
+ * current pgd to avoid unnecessary TLB flushes.
*/
- write_cr3(read_cr3());
+ pgd = read_cr3();
+ if (__pa(pudp) >= pgd && __pa(pudp) < (pgd + sizeof(pgd_t)*PTRS_PER_PGD))
+ write_cr3(pgd);
}
#define pud_page(pud) \