linux-kernel - [PATCH v2 2/6] x86/mce: Make mce=nobootlog work again

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Message-Id: <20200103150722.20313-3-jschoenh@amazon.de>
Date:   Fri,  3 Jan 2020 16:07:18 +0100
From:   Jan H. Schönherr <jschoenh@...zon.de>
To:     Borislav Petkov <bp@...en8.de>
Cc:     Jan H. Schönherr <jschoenh@...zon.de>,
        Yazen Ghannam <yazen.ghannam@....com>,
        linux-kernel@...r.kernel.org, linux-edac@...r.kernel.org,
        Tony Luck <tony.luck@...el.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org
Subject: [PATCH v2 2/6] x86/mce: Make mce=nobootlog work again

Since commit 8b38937b7ab5 ("x86/mce: Do not enter deferred errors into
the generic pool twice") the mce=nobootlog option has become mostly
ineffective (after being only slightly ineffective before), as the
code is taking actions on MCEs left over from boot when they have a
usable address.

Move the check for MCP_DONTLOG a bit outward to make it effective again.

Also, since commit 011d82611172 ("RAS: Add a Corrected Errors Collector")
the two branches of the remaining "if" the bottom of machine_check_poll()
do same. Unify them.

Signed-off-by: Jan H. Schönherr <jschoenh@...zon.de>
---
Changes v1->v2:
- remove an indentation level in favor of a goto (requested by Boris)
- don't mention Linux version (per remark from Boris)
---
 arch/x86/kernel/cpu/mce/core.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index 16134ce587fd..0ccd6cf3402d 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -750,26 +750,22 @@ bool machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
 log_it:
 		error_seen = true;
 
-		mce_read_aux(&m, i);
+		if (flags & MCP_DONTLOG)
+			goto clear_it;
 
+		mce_read_aux(&m, i);
 		m.severity = mce_severity(&m, mca_cfg.tolerant, NULL, false);
-
 		/*
 		 * Don't get the IP here because it's unlikely to
 		 * have anything to do with the actual error location.
 		 */
-		if (!(flags & MCP_DONTLOG) && !mca_cfg.dont_log_ce)
-			mce_log(&m);
-		else if (mce_usable_address(&m)) {
-			/*
-			 * Although we skipped logging this, we still want
-			 * to take action. Add to the pool so the registered
-			 * notifiers will see it.
-			 */
-			if (!mce_gen_pool_add(&m))
-				mce_schedule_work();
-		}
 
+		if (mca_cfg.dont_log_ce && !mce_usable_address(&m))
+			goto clear_it;
+
+		mce_log(&m);
+
+clear_it:
 		/*
 		 * Clear state for this bank.
 		 */
-- 
2.22.0.3.gb49bb57c8208.dirty