linux-kernel - [PATCH 4/6 v5] acpi/ghes: Add helper for CPER CXL protocol errors checks

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Message-ID: <20251017133357.1150982-5-fabio.m.de.francesco@linux.intel.com>
Date: Fri, 17 Oct 2025 15:30:49 +0200
From: "Fabio M. De Francesco" <fabio.m.de.francesco@...ux.intel.com>
To: linux-cxl@...r.kernel.org
Cc: "Rafael J . Wysocki" <rafael@...nel.org>,
	Len Brown <lenb@...nel.org>,
	Tony Luck <tony.luck@...el.com>,
	Borislav Petkov <bp@...en8.de>,
	Hanjun Guo <guohanjun@...wei.com>,
	Mauro Carvalho Chehab <mchehab@...nel.org>,
	Shuai Xue <xueshuai@...ux.alibaba.com>,
	Davidlohr Bueso <dave@...olabs.net>,
	Jonathan Cameron <jonathan.cameron@...wei.com>,
	Dave Jiang <dave.jiang@...el.com>,
	Alison Schofield <alison.schofield@...el.com>,
	Vishal Verma <vishal.l.verma@...el.com>,
	Ira Weiny <ira.weiny@...el.com>,
	Dan Williams <dan.j.williams@...el.com>,
	Mahesh J Salgaonkar <mahesh@...ux.ibm.com>,
	Oliver O'Halloran <oohall@...il.com>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Sunil V L <sunilvl@...tanamicro.com>,
	Xiaofei Tan <tanxiaofei@...wei.com>,
	Mario Limonciello <mario.limonciello@....com>,
	Huacai Chen <chenhuacai@...nel.org>,
	Heinrich Schuchardt <heinrich.schuchardt@...onical.com>,
	Arnd Bergmann <arnd@...db.de>,
	"Fabio M . De Francesco" <fabio.m.de.francesco@...ux.intel.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...nel.org>,
	Guo Weikang <guoweikang.kernel@...il.com>,
	Xin Li <xin@...or.com>,
	Will Deacon <will@...nel.org>,
	Huang Yiwei <quic_hyiwei@...cinc.com>,
	Gavin Shan <gshan@...hat.com>,
	Smita Koralahalli <Smita.KoralahalliChannabasappa@....com>,
	Uwe Kleine-König <u.kleine-koenig@...libre.com>,
	Li Ming <ming.li@...omail.com>,
	Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
	Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>,
	Karolina Stolarek <karolina.stolarek@...cle.com>,
	Jon Pan-Doh <pandoh@...gle.com>,
	Lukas Wunner <lukas@...ner.de>,
	Shiju Jose <shiju.jose@...wei.com>,
	linux-kernel@...r.kernel.org,
	linux-acpi@...r.kernel.org,
	linuxppc-dev@...ts.ozlabs.org,
	linux-pci@...r.kernel.org
Subject: [PATCH 4/6 v5] acpi/ghes: Add helper for CPER CXL protocol errors checks

Move the CPER CXL protocol errors validity checks out of
cxl_cper_post_prot_err() to cxl_cper_sec_prot_err_valid() and check the
serial number only for CXL agents that are CXL devices (UEFI v2.10,
Appendix N.2.13).

Signed-off-by: Fabio M. De Francesco <fabio.m.de.francesco@...ux.intel.com>
---
 drivers/acpi/apei/ghes.c | 32 ++++++++++++++++++++++----------
 include/cxl/event.h      | 10 ++++++++++
 2 files changed, 32 insertions(+), 10 deletions(-)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index d6fe5f020e96e..e69ae864f43d3 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -706,30 +706,42 @@ static DEFINE_KFIFO(cxl_cper_prot_err_fifo, struct cxl_cper_prot_err_work_data,
 static DEFINE_SPINLOCK(cxl_cper_prot_err_work_lock);
 struct work_struct *cxl_cper_prot_err_work;
 
-static void cxl_cper_post_prot_err(struct cxl_cper_sec_prot_err *prot_err,
-				   int severity)
+int cxl_cper_sec_prot_err_valid(struct cxl_cper_sec_prot_err *prot_err)
 {
-	struct cxl_cper_prot_err_work_data wd;
-	u8 *dvsec_start, *cap_start;
-
 	if (!(prot_err->valid_bits & PROT_ERR_VALID_AGENT_ADDRESS)) {
 		pr_err_ratelimited("CXL CPER invalid agent type\n");
-		return;
+		return -EINVAL;
 	}
 
 	if (!(prot_err->valid_bits & PROT_ERR_VALID_ERROR_LOG)) {
 		pr_err_ratelimited("CXL CPER invalid protocol error log\n");
-		return;
+		return -EINVAL;
 	}
 
 	if (prot_err->err_len != sizeof(struct cxl_ras_capability_regs)) {
 		pr_err_ratelimited("CXL CPER invalid RAS Cap size (%u)\n",
 				   prot_err->err_len);
-		return;
+		return -EINVAL;
 	}
 
-	if (!(prot_err->valid_bits & PROT_ERR_VALID_SERIAL_NUMBER))
-		pr_warn(FW_WARN "CXL CPER no device serial number\n");
+	if ((prot_err->agent_type == RCD || prot_err->agent_type == DEVICE ||
+	     prot_err->agent_type == LD || prot_err->agent_type == FMLD) &&
+	    !(prot_err->valid_bits & PROT_ERR_VALID_SERIAL_NUMBER))
+		pr_warn_ratelimited(FW_WARN
+				    "CXL CPER no device serial number\n");
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cxl_cper_sec_prot_err_valid);
+
+static void cxl_cper_post_prot_err(struct cxl_cper_sec_prot_err *prot_err,
+				   int severity)
+{
+	struct cxl_cper_prot_err_work_data wd;
+	u8 *dvsec_start, *cap_start;
+
+	if (cxl_cper_sec_prot_err_valid(prot_err))
+		return;
 
 	guard(spinlock_irqsave)(&cxl_cper_prot_err_work_lock);
 
diff --git a/include/cxl/event.h b/include/cxl/event.h
index 6fd90f9cc2034..e1deb66c2197e 100644
--- a/include/cxl/event.h
+++ b/include/cxl/event.h
@@ -320,4 +320,14 @@ static inline int cxl_cper_prot_err_kfifo_get(struct cxl_cper_prot_err_work_data
 }
 #endif
 
+#ifdef CONFIG_ACPI_APEI_PCIEAER
+int cxl_cper_sec_prot_err_valid(struct cxl_cper_sec_prot_err *prot_err);
+#else
+static inline int
+cxl_cper_sec_prot_err_valid(struct cxl_cper_sec_prot_err *prot_err)
+{
+	return -EINVAL;
+}
+#endif
+
 #endif /* _LINUX_CXL_EVENT_H */
-- 
2.51.0