Commit ca73d3bf authored Aug 07, 2024 by Udit Kumar Committed by felix Aug 07, 2024

serial: 8250_omap: Fix Errata i2310 with RX FIFO level check

stable inclusion
from stable-v5.10.221
commit 0a95f0f6d64eb9e80bb6008626f68182c32d3976
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAGEP6
CVE: CVE-2024-42095

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=0a95f0f6d64eb9e80bb6008626f68182c32d3976

--------------------------------

commit c128a1b0523b685c8856ddc0ac0e1caef1fdeee5 upstream.

Errata i2310[0] says, Erroneous timeout can be triggered,
if this Erroneous interrupt is not cleared then it may leads
to storm of interrupts.

Commit 9d141c1e6157 ("serial: 8250_omap: Implementation of Errata i2310")
which added the workaround but missed ensuring RX FIFO is really empty
before applying the errata workaround as recommended in the errata text.
Fix this by adding back check for UART_OMAP_RX_LVL to be 0 for
workaround to take effect.

[0] https://www.ti.com/lit/pdf/sprz536

 page 23

Fixes: 9d141c1e6157 ("serial: 8250_omap: Implementation of Errata i2310")
Cc: stable@vger.kernel.org
Reported-by: Vignesh Raghavendra <vigneshr@ti.com>
Closes: https://lore.kernel.org/all/e96d0c55-0b12-4cbf-9d23-48963543de49@ti.com/


Signed-off-by: Udit Kumar <u-kumar1@ti.com>
Link: https://lore.kernel.org/r/20240625160725.2102194-1-u-kumar1@ti.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Felix Fu <fuzhen5@huawei.com>

parent 0475afdd

drivers/tty/serial/8250/8250_omap.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -656,7 +656,8 @@ static irqreturn_t omap8250_irq(int irq, void *dev_id)
		* https://www.ti.com/lit/pdf/sprz536
		*/
		if (priv->habit & UART_RX_TIMEOUT_QUIRK &&
		(iir & UART_IIR_RX_TIMEOUT) == UART_IIR_RX_TIMEOUT) {
		(iir & UART_IIR_RX_TIMEOUT) == UART_IIR_RX_TIMEOUT &&
		serial_port_in(port, UART_OMAP_RX_LVL) == 0) {
		unsigned char efr2, timeout_h, timeout_l;

		efr2 = serial_in(up, UART_OMAP_EFR2);