From: Arseny Solokha <asolokha@kb.kras.ru>
Date: Wed, 4 Feb 2015 02:18:02 +0000 (+1100)
Subject: powerpc/mm: Warn on flushing tlb page in kernel context
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=c2c896bee08e1461fc24f9bf7dd57e2c63f6db70;p=deliverable%2Flinux.git

powerpc/mm: Warn on flushing tlb page in kernel context

Function __flush_tlb_page() must only be called for user contexts, so
put in extra hardening to warn on calling it for kernel context.

Signed-off-by: Arseny Solokha <asolokha@kb.kras.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---

diff --git a/arch/powerpc/mm/tlb_nohash.c b/arch/powerpc/mm/tlb_nohash.c
index ab0616b0e6c2..cbd3d069897f 100644
--- a/arch/powerpc/mm/tlb_nohash.c
+++ b/arch/powerpc/mm/tlb_nohash.c
@@ -284,7 +284,11 @@ void __flush_tlb_page(struct mm_struct *mm, unsigned long vmaddr,
 	struct cpumask *cpu_mask;
 	unsigned int pid;
 
-	if (unlikely(!mm))
+	/*
+	 * This function as well as __local_flush_tlb_page() must only be called
+	 * for user contexts.
+	 */
+	if (unlikely(WARN_ON(!mm)))
 		return;
 
 	preempt_disable();