commit: 90eed7d87b748f9c0d11b9bad64a4c41e31b78c4
From: Paul Mundt <[email protected]>
Date: Tue, 24 Jul 2012 13:15:54 +0900
Subject: 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]>
---
 arch/sh/mm/fault.c |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c
index 1fc25d8..3bdc1ad 100644
--- 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,
-- 
1.7.3.4
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