x86/mce: Fix check for processor context when machine check was taken.
Linus pointed out that there was no value is checking whether m->ip was zero - because zero is a legimate value. If we have a reliable (or faked in the VM86 case) "m->cs" we can use it to tell whether we were in user mode or kernelwhen the machine check hit. Reported-by: Linus Torvalds <torvalds@linuxfoundation.org> Cc: <stable@vger.kernel.org> Signed-off-by: Tony Luck <tony.luck@intel.com>
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@ -165,15 +165,19 @@ static struct severity {
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};
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/*
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* If the EIPV bit is set, it means the saved IP is the
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* instruction which caused the MCE.
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* If mcgstatus indicated that ip/cs on the stack were
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* no good, then "m->cs" will be zero and we will have
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* to assume the worst case (IN_KERNEL) as we actually
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* have no idea what we were executing when the machine
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* check hit.
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* If we do have a good "m->cs" (or a faked one in the
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* case we were executing in VM86 mode) we can use it to
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* distinguish an exception taken in user from from one
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* taken in the kernel.
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*/
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static int error_context(struct mce *m)
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{
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if (m->mcgstatus & MCG_STATUS_EIPV)
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return (m->ip && (m->cs & 3) == 3) ? IN_USER : IN_KERNEL;
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/* Unknown, assume kernel */
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return IN_KERNEL;
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return ((m->cs & 3) == 3) ? IN_USER : IN_KERNEL;
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}
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int mce_severity(struct mce *m, int tolerant, char **msg)
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