From: Andi Kleen Date: Fri, 19 Nov 2010 12:16:22 +0000 (+0100) Subject: MCE: Fix vm86 handling for 32bit mce handler X-Git-Tag: firefly_0821_release~3680^2~2655^2~4 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=a129a7c84582629741e5fa6f40026efcd7a65bd4;p=firefly-linux-kernel-4.4.55.git MCE: Fix vm86 handling for 32bit mce handler 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 Cc: Signed-off-by: Tony Luck --- diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index 66e1c51be084..5f793e6c854b 100644 --- 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(struct mce *m, struct pt_regs *regs) 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)