[PATCH 1/7] x86/mce: Handle an in-kernel MCE decoder

Borislav Petkov
2017-08-25T10:24:23Z

From: Borislav Petkov <bp@suse.de>

Change the MCE decoding flow to issue the trace_mce_record() tracepoint
only when there's no decoder registered on the decoder chain. If there
is, it will do some massaging on the MCE info before issuing it through
the tracepoint.

Signed-off-by: Borislav Petkov <bp@suse.de>
---
arch/x86/include/asm/mce.h | 4 +++-
arch/x86/kernel/cpu/mcheck/mce.c | 9 ++++++++-
2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h
index 181264989db5..ba4c99ace544 100644
--- a/arch/x86/include/asm/mce.h
+++ b/arch/x86/include/asm/mce.h
@@ -146,6 +146,7 @@ struct mca_config {
bool ser;
bool recovery;
bool bios_cmci_threshold;
+ bool has_decoder;
u8 banks;
s8 bootlog;
int tolerant;
@@ -195,7 +196,8 @@ enum mce_notifier_prios {
MCE_PRIO_SRAO = INT_MAX - 1,
MCE_PRIO_EXTLOG = INT_MAX - 2,
MCE_PRIO_NFIT = INT_MAX - 3,
- MCE_PRIO_EDAC = INT_MAX - 4,
+ MCE_PRIO_DECODER = INT_MAX - 4,
+ MCE_PRIO_EDAC = INT_MAX - 5,
MCE_PRIO_MCELOG = 1,
MCE_PRIO_LOWEST = 0,
};
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 3b413065c613..dcf75f40e031 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -163,6 +163,9 @@ void mce_register_decode_chain(struct notifier_block *nb)

atomic_inc(&num_notifiers);

+ if (nb->priority == MCE_PRIO_DECODER)
+ mca_cfg.has_decoder = true;
+
blocking_notifier_chain_register(&x86_mce_decoder_chain, nb);
}
EXPORT_SYMBOL_GPL(mce_register_decode_chain);
@@ -171,6 +174,9 @@ void mce_unregister_decode_chain(struct notifier_block *nb)
{
atomic_dec(&num_notifiers);

+ if (nb->priority == MCE_PRIO_DECODER)
+ mca_cfg.has_decoder = false;
+
blocking_notifier_chain_unregister(&x86_mce_decoder_chain, nb);
}
EXPORT_SYMBOL_GPL(mce_unregister_decode_chain);
@@ -557,7 +563,8 @@ static int mce_first_notifier(struct notifier_block *nb, unsigned long val,
return NOTIFY_STOP;

/* Emit the trace record: */
- trace_mce_record(m);
+ if (!mca_cfg.has_decoder)
+ trace_mce_record(m);

set_bit(0, &mce_need_notify);

--
2.13.0