From: Mark Fortescue <mark@mtfhpc.demon.co.uk>
Date: Tue, 31 Jul 2007 09:03:11 +0000 (-0700)
Subject: [SPARC]: Fix exec failures on sun4c.
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=da4e9fea85ea42c9c6ce163a85d5164efbec31a2;p=sagit-ice-cold%2Fkernel_xiaomi_msm8998.git

[SPARC]: Fix exec failures on sun4c.

This deals with a sun4c issue caused by commit b6a2fea39318e43fee84fa7b0b90d68bed92d2ba:
mm: variable length argument support.

The new way the code works means that sun4c_update_mmu_cache gets
called before a context has been selected, which results in invalid
operation of the underling mm code.

Simply ignoring update requests when there is no valid context solves
the problem.

Signed-off-by Mark Fortescue <mark@mtfhpc.demon.co.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/arch/sparc/mm/sun4c.c b/arch/sparc/mm/sun4c.c
index a57a366e339a..79d60d86f6f8 100644
--- a/arch/sparc/mm/sun4c.c
+++ b/arch/sparc/mm/sun4c.c
@@ -1999,6 +1999,9 @@ void sun4c_update_mmu_cache(struct vm_area_struct *vma, unsigned long address, p
 	unsigned long flags;
 	int pseg;
 
+	if (vma->vm_mm->context == NO_CONTEXT)
+		return;
+
 	local_irq_save(flags);
 	address &= PAGE_MASK;
 	if ((pseg = sun4c_get_segmap(address)) == invalid_segment) {