lkml.org 
[lkml]   [2012]   [May]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[ 92/94] MCE: Fix vm86 handling for 32bit mce handler
3.3-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Andi Kleen <andi@firstfloor.org>

commit a129a7c84582629741e5fa6f40026efcd7a65bd4 upstream.

When running on 32bit the mce handler could misinterpret
vm86 mode as ring 0. This can affect whether it does recovery
or not; it was possible to panic when recovery was actually
possible.

Fix this by always forcing vm86 to look like ring 3.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/x86/kernel/cpu/mcheck/mce.c | 8 ++++++++
1 file changed, 8 insertions(+)

--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -437,6 +437,14 @@ static inline void mce_gather_info(struc
if (m->mcgstatus & (MCG_STATUS_RIPV|MCG_STATUS_EIPV)) {
m->ip = regs->ip;
m->cs = regs->cs;
+
+ /*
+ * When in VM86 mode make the cs look like ring 3
+ * always. This is a lie, but it's better than passing
+ * the additional vm86 bit around everywhere.
+ */
+ if (v8086_mode(regs))
+ m->cs |= 3;
}
/* Use accurate RIP reporting if available. */
if (rip_msr)



\
 
 \ /
  Last update: 2012-05-27 04:21    [W:0.590 / U:5.992 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site