[3.8.y.z extended stable] Patch "MIPS: Hibernate: Flush TLB entries in swsusp_arch_resume()" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    MIPS: Hibernate: Flush TLB entries in swsusp_arch_resume()

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.22.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

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>From d7ad18e97ff5609d589fbc132f1b6a81e3e2eb91 Mon Sep 17 00:00:00 2001
From: Huacai Chen <chenhc at lemote.com>
Date: Sat, 22 Mar 2014 17:21:44 +0800
Subject: MIPS: Hibernate: Flush TLB entries in swsusp_arch_resume()

commit c14af233fbe279d0e561ecf84f1208b1bae087ef upstream.

The original MIPS hibernate code flushes cache and TLB entries in
swsusp_arch_resume(). But they are removed in Commit 44eeab67416711
(MIPS: Hibernation: Remove SMP TLB and cacheflushing code.). A cross-
CPU flush is surely unnecessary because all but the local CPU have
already been disabled. But a local flush (at least the TLB flush) is
needed. When we do hibernation on Loongson-3 with an E1000E NIC, it is
very easy to produce a kernel panic (kernel page fault, or unaligned
access). The root cause is E1000E driver use vzalloc_node() to allocate
pages, the stale TLB entries of the booting kernel will be misused by
the resumed target kernel.

Signed-off-by: Huacai Chen <chenhc at lemote.com>
Cc: John Crispin <john at phrozen.org>
Cc: Steven J. Hill <Steven.Hill at imgtec.com>
Cc: Aurelien Jarno <aurelien at aurel32.net>
Cc: linux-mips at linux-mips.org
Cc: Fuxin Zhang <zhangfx at lemote.com>
Cc: Zhangjin Wu <wuzhangjin at gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/6643/
Signed-off-by: Ralf Baechle <ralf at linux-mips.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 arch/mips/power/hibernate.S | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/mips/power/hibernate.S b/arch/mips/power/hibernate.S
index 61e2558..63bc9e5 100644
--- a/arch/mips/power/hibernate.S
+++ b/arch/mips/power/hibernate.S
@@ -43,6 +43,7 @@ LEAF(swsusp_arch_resume)
 	bne t1, t3, 1b
 	PTR_L t0, PBE_NEXT(t0)
 	bnez t0, 0b
+	jal local_flush_tlb_all /* Avoid TLB mismatch after kernel resume */
 	PTR_LA t0, saved_regs
 	PTR_L ra, PT_R31(t0)
 	PTR_L sp, PT_R29(t0)
--
1.9.1