netdev - [PATCH net-next] ptp: ocp: add UPF_NO_THRE

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: <20220309223427.34745-1-jonathan.lemon@gmail.com>
Date:   Wed,  9 Mar 2022 14:34:27 -0800
From:   Jonathan Lemon <jonathan.lemon@...il.com>
To:     netdev@...r.kernel.org
Cc:     kuba@...nel.org, davem@...emloft.net, richardcochran@...il.com,
        kernel-team@...com
Subject: [PATCH net-next] ptp: ocp: add UPF_NO_THRE_TEST flag for serial ports

From: Jonathan Lemon <bsd@...com>

The serial port driver attempts to test for correct THRE behavior
on startup.  However, it does this by disabling interrupts, and
then intentionally trying to trigger an interrupt in order to see
if the IIR bit is set in the UART.

However, in this FPGA design, the UART interrupt is generated
through the MSI vector, so when interrupts are re-enabled after
the test, the DMAR-IR reports an unhandled IRTE entry, since
no irq handler is installed at this point - it is installed
after the test.

This only happens on the /second/ open of the UART, since on the
first open, the x86_vector has installed and activated by the
driver probe, and is correctly handled.  When the serial port is
closed for the first time, this vector is deactivated and removed,
leading to this error.

Signed-off-by: Jonathan Lemon <jonathan.lemon@...il.com>
---
 drivers/ptp/ptp_ocp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/ptp/ptp_ocp.c b/drivers/ptp/ptp_ocp.c
index 36c09269a12d..64cc92c2426b 100644
--- a/drivers/ptp/ptp_ocp.c
+++ b/drivers/ptp/ptp_ocp.c
@@ -1752,7 +1752,7 @@ ptp_ocp_serial_line(struct ptp_ocp *bp, struct ocp_resource *r)
 	uart.port.mapbase = pci_resource_start(pdev, 0) + r->offset;
 	uart.port.irq = pci_irq_vector(pdev, r->irq_vec);
 	uart.port.uartclk = 50000000;
-	uart.port.flags = UPF_FIXED_TYPE | UPF_IOREMAP;
+	uart.port.flags = UPF_FIXED_TYPE | UPF_IOREMAP | UPF_NO_THRE_TEST;
 	uart.port.type = PORT_16550A;

 	return serial8250_register_8250_port(&uart);
-- 
2.31.1