| | Date | Sun, 27 May 2012 10:05:55 +0900 | | From | Greg KH <> | | Subject | [ 92/94] MCE: Fix vm86 handling for 32bit mce handler |
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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)
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