linux-kernel - [PATCH pci-next] pci/edr: Ignore Surprise Down error on hot removal

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20240304090819.3812465-1-haifeng.zhao@linux.intel.com>
Date: Mon,  4 Mar 2024 04:08:19 -0500
From: Ethan Zhao <haifeng.zhao@...ux.intel.com>
To: bhelgaas@...gle.com,
	lukas@...ner.de
Cc: Smita.KoralahalliChannabasappa@....com,
	ilpo.jarvinen@...ux.intel.com,
	sathyanarayanan.kuppuswamy@...ux.intel.com,
	linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	kbusch@...nel.org,
	Ethan Zhao <haifeng.zhao@...ux.intel.com>
Subject: [PATCH pci-next] pci/edr: Ignore Surprise Down error on hot removal

Per PCI firmware spec r3.3 sec 4.6.12, for firmware first mode DPC
handling path, FW should clear UC errors logged by port and bring link
out of DPC, but because of ambiguity of wording in the spec, some BIOSes
doesn't clear the surprise down error and the error bits in pci status,
still notify OS to handle it. thus following trick is needed in EDR when
double reporting (hot removal interrupt && dpc notification) is hit.

https://patchwork.kernel.org/project/linux-pci/patch/20240207181854.
121335-1-Smita.KoralahalliChannabasappa@....com/

Signed-off-by: Ethan Zhao <haifeng.zhao@...ux.intel.com>
---
 drivers/pci/pci.h      | 1 +
 drivers/pci/pcie/dpc.c | 9 +++++----
 drivers/pci/pcie/edr.c | 3 +++
 3 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 50134b5e3235..3787bb32e724 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -443,6 +443,7 @@ void pci_save_dpc_state(struct pci_dev *dev);
 void pci_restore_dpc_state(struct pci_dev *dev);
 void pci_dpc_init(struct pci_dev *pdev);
 void dpc_process_error(struct pci_dev *pdev);
+bool dpc_handle_surprise_removal(struct pci_dev *pdev);
 pci_ers_result_t dpc_reset_link(struct pci_dev *pdev);
 bool pci_dpc_recovered(struct pci_dev *pdev);
 #else
diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index 98b42e425bb9..be79f205e04c 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -319,8 +319,10 @@ static void pci_clear_surpdn_errors(struct pci_dev *pdev)
 	pcie_capability_write_word(pdev, PCI_EXP_DEVSTA, PCI_EXP_DEVSTA_FED);
 }
 
-static void dpc_handle_surprise_removal(struct pci_dev *pdev)
+bool  dpc_handle_surprise_removal(struct pci_dev *pdev)
 {
+	if (!dpc_is_surprise_removal(pdev))
+		return false;
 	if (!pcie_wait_for_link(pdev, false)) {
 		pci_info(pdev, "Data Link Layer Link Active not cleared in 1000 msec\n");
 		goto out;
@@ -338,6 +340,7 @@ static void dpc_handle_surprise_removal(struct pci_dev *pdev)
 out:
 	clear_bit(PCI_DPC_RECOVERED, &pdev->priv_flags);
 	wake_up_all(&dpc_completed_waitqueue);
+	return true;
 }
 
 static bool dpc_is_surprise_removal(struct pci_dev *pdev)
@@ -362,10 +365,8 @@ static irqreturn_t dpc_handler(int irq, void *context)
 	 * According to PCIe r6.0 sec 6.7.6, errors are an expected side effect
 	 * of async removal and should be ignored by software.
 	 */
-	if (dpc_is_surprise_removal(pdev)) {
-		dpc_handle_surprise_removal(pdev);
+	if (dpc_handle_surprise_removal(pdev))
 		return IRQ_HANDLED;
-	}
 
 	dpc_process_error(pdev);
 
diff --git a/drivers/pci/pcie/edr.c b/drivers/pci/pcie/edr.c
index 5f4914d313a1..556edfb2696a 100644
--- a/drivers/pci/pcie/edr.c
+++ b/drivers/pci/pcie/edr.c
@@ -184,6 +184,9 @@ static void edr_handle_event(acpi_handle handle, u32 event, void *data)
 		goto send_ost;
 	}
 
+	if (dpc_handle_surprise_removal(edev))
+		goto send_ost;
+
 	dpc_process_error(edev);
 	pci_aer_raw_clear_status(edev);
 

base-commit: a66f2b4a4d365dc4bac35576f3a9d4f5982f1d63
-- 
2.31.1