Re: [PATCH] x86/MCE: Remove MCP_TIMESTAMP

From: Thomas Gleixner
Date: Tue Nov 08 2016 - 16:57:37 EST


On Tue, 8 Nov 2016, Borislav Petkov wrote:

> On Tue, Nov 08, 2016 at 10:14:04PM +0100, Thomas Gleixner wrote:
> > And yes, you should spend the extra cycles. Adding a flags argument to
> > mce_setup() and propagate it through the various callsites shouldn't be
> > that hard and would make the stuff obvious instead of obfuscated.
>
> Sure, that's already on my TODO. I want to take a look at it when I have
> a quiet moment.

So for now we should fold something like the below into this patch.

Thanks,

tglx

8<--------------------

--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -706,6 +706,15 @@ bool machine_check_poll(enum mcp_flags f

mce_gather_info(&m, NULL);

+ /*
+ * m.tsc was set in mce_setup(). Clear it if not requested.
+ *
+ * FIXME: Propagate @flags to mce_gather_info/mce_setup() to avoid
+ * that dance
+ */
+ if (!(flags & MCP_TIMESTAMP))
+ m.tsc = 0;
+
for (i = 0; i < mca_cfg.banks; i++) {
if (!mce_banks[i].ctl || !test_bit(i, *b))
continue;
@@ -734,9 +743,6 @@ bool machine_check_poll(enum mcp_flags f

mce_read_aux(&m, i);

- if (!(flags & MCP_TIMESTAMP))
- m.tsc = 0;
-
severity = mce_severity(&m, mca_cfg.tolerant, NULL, false);

if (severity == MCE_DEFERRED_SEVERITY && memory_error(&m))