sh: Fix up recursive fault in oops with unset TTB.

Presently the oops code looks for the pgd either from the mm context or the cached TTB value. There are presently cases where the TTB can be unset or otherwise cleared by hardware, which we weren't handling, resulting in recursive faults on the NULL pgd. In these cases we can simply reload from swapper_pg_dir and continue on as normal. Cc: [email protected] Signed-off-by: Paul Mundt <[email protected]>
vincehsu · Jul 25, 2012 · 90eed7d · 90eed7d
1 parent 92f53a8
commit 90eed7d
Showing 1 changed file with 6 additions and 2 deletions.
diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c
@@ -58,11 +58,15 @@ static void show_pte(struct mm_struct *mm, unsigned long addr)
 {
 	pgd_t *pgd;
 
-	if (mm)
+	if (mm) {
 		pgd = mm->pgd;
-	else
+	} else {
 		pgd = get_TTB();
 
+		if (unlikely(!pgd))
+			pgd = swapper_pg_dir;
+	}
+
 	printk(KERN_ALERT "pgd = %p\n", pgd);
 	pgd += pgd_index(addr);
 	printk(KERN_ALERT "[%08lx] *pgd=%0*Lx", addr,