This basically restores slightly modified version of original
sync_global_pgds() which we had before foldedl p4d was introduced.
The only modification is protection against 'address' overflow.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
arch/x86/mm/init_64.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 47 insertions(+)
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index a991f5c4c2c4..d637893ac8c2 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -92,6 +92,52 @@ __setup("noexec32=", nonx32_setup);
* When memory was added/removed make sure all the processes MM have
* suitable PGD entries in the local PGD level page.
*/
+#ifdef CONFIG_X86_5LEVEL
+void sync_global_pgds(unsigned long start, unsigned long end, int removed)
+{
+ unsigned long address;
+
+ for (address = start; address <= end && address >= start;
+ address += PGDIR_SIZE) {
+ const pgd_t *pgd_ref = pgd_offset_k(address);
+ struct page *page;
+
+ /*
+ * When it is called after memory hot remove, pgd_none()
+ * returns true. In this case (removed == 1), we must clear
+ * the PGD entries in the local PGD level page.
+ */
+ if (pgd_none(*pgd_ref) && !removed)
+ continue;
+
+ spin_lock(&pgd_lock);
+ list_for_each_entry(page, &pgd_list, lru) {
+ pgd_t *pgd;
+ spinlock_t *pgt_lock;
+
+ pgd = (pgd_t *)page_address(page) + pgd_index(address);
+ /* the pgt_lock only for Xen */
+ pgt_lock = &pgd_page_get_mm(page)->page_table_lock;
+ spin_lock(pgt_lock);
+
+ if (!pgd_none(*pgd_ref) && !pgd_none(*pgd))
+ BUG_ON(pgd_page_vaddr(*pgd)
+ != pgd_page_vaddr(*pgd_ref));
+
+ if (removed) {
+ if (pgd_none(*pgd_ref) && !pgd_none(*pgd))
+ pgd_clear(pgd);
+ } else {
+ if (pgd_none(*pgd))
+ set_pgd(pgd, *pgd_ref);
+ }
+
+ spin_unlock(pgt_lock);
+ }
+ spin_unlock(&pgd_lock);
+ }
+}
+#else
void sync_global_pgds(unsigned long start, unsigned long end, int removed)
{
unsigned long address;
@@ -145,6 +191,7 @@ void sync_global_pgds(unsigned long start, unsigned long end, int removed)
spin_unlock(&pgd_lock);
}
}
+#endif
/*
* NOTE: This function is marked __ref because it calls __init function
--
2.10.2
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