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Commit 09371957 authored by Borislav Petkov's avatar Borislav Petkov Committed by Borislav Petkov
Browse files

x86, MCE: Drain mcelog buffer 



Add a function which drains whatever MCEs were logged in already during
boot and before the decoder chains were registered.

Signed-off-by: default avatarBorislav Petkov <borislav.petkov@amd.com>
parent 3653ada5

arch/x86/kernel/cpu/mcheck/mce.c

+39 −0
Original line number Diff line number Diff line
@@ -189,9 +189,48 @@ void mce_log(struct mce *mce) 
	set_bit(0, &mce_need_notify);

}



static void drain_mcelog_buffer(void)

{

	unsigned int next, i, prev = 0;



	next = rcu_dereference_check_mce(mcelog.next);



	do {

		struct mce *m;



		/* drain what was logged during boot */

		for (i = prev; i < next; i++) {

			unsigned long start = jiffies;

			unsigned retries = 1;



			m = &mcelog.entry[i];



			while (!m->finished) {

				if (time_after_eq(jiffies, start + 2*retries))

					retries++;



				cpu_relax();



				if (!m->finished && retries >= 4) {

					pr_err("MCE: skipping error being logged currently!\n");

					break;

				}

			}

			smp_rmb();

			atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, m);

		}



		memset(mcelog.entry + prev, 0, (next - prev) * sizeof(*m));

		prev = next;

		next = cmpxchg(&mcelog.next, prev, 0);

	} while (next != prev);

}





void mce_register_decode_chain(struct notifier_block *nb)

{

	atomic_notifier_chain_register(&x86_mce_decoder_chain, nb);

	drain_mcelog_buffer();

}

EXPORT_SYMBOL_GPL(mce_register_decode_chain);