From: Peng Fan peng.fan@nxp.com
[ Upstream commit ef25e16ea9674b713a68c3bda821556ce9901254 ]
There maybe pending USR interrupt before requesting irq, however uart_add_one_port has not executed, so there will be kernel panic: [ 0.795668] Unable to handle kernel NULL pointer dereference at virtual addre ss 0000000000000080 [ 0.802701] Mem abort info: [ 0.805367] ESR = 0x0000000096000004 [ 0.808950] EC = 0x25: DABT (current EL), IL = 32 bits [ 0.814033] SET = 0, FnV = 0 [ 0.816950] EA = 0, S1PTW = 0 [ 0.819950] FSC = 0x04: level 0 translation fault [ 0.824617] Data abort info: [ 0.827367] ISV = 0, ISS = 0x00000004 [ 0.831033] CM = 0, WnR = 0 [ 0.833866] [0000000000000080] user address but active_mm is swapper [ 0.839951] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP [ 0.845953] Modules linked in: [ 0.848869] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.1.1+g56321e101aca #1 [ 0.855617] Hardware name: Freescale i.MX8MP EVK (DT) [ 0.860452] pstate: 000000c5 (nzcv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 0.867117] pc : __imx_uart_rxint.constprop.0+0x11c/0x2c0 [ 0.872283] lr : imx_uart_int+0xf8/0x1ec
The issue only happends in the inmate linux when Jailhouse hypervisor enabled. The test procedure is: while true; do jailhouse enable imx8mp.cell jailhouse cell linux xxxx sleep 10 jailhouse cell destroy 1 jailhouse disable sleep 5 done
And during the upper test, press keys to the 2nd linux console. When `jailhouse cell destroy 1`, the 2nd linux has no chance to put the uart to a quiese state, so USR1/2 may has pending interrupts. Then when `jailhosue cell linux xx` to start 2nd linux again, the issue trigger.
In order to disable irqs before requesting them, both UCR1 and UCR2 irqs should be disabled, so here fix that, disable the Ageing Timer interrupt in UCR2 as UCR1 does.
Fixes: 8a61f0c70ae6 ("serial: imx: Disable irqs before requesting them") Suggested-by: Sherry Sun sherry.sun@nxp.com Reviewed-by: Sherry Sun sherry.sun@nxp.com Signed-off-by: Peng Fan peng.fan@nxp.com Acked-by: Jason Liu jason.hui.liu@nxp.com Link: https://lore.kernel.org/r/20230206013016.29352-1-sherry.sun@nxp.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/tty/serial/imx.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index f3f03cef3c7a9..f07c4f9ff13c0 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -2377,6 +2377,11 @@ static int imx_uart_probe(struct platform_device *pdev) ucr1 &= ~(UCR1_ADEN | UCR1_TRDYEN | UCR1_IDEN | UCR1_RRDYEN | UCR1_RTSDEN); imx_uart_writel(sport, ucr1, UCR1);
+ /* Disable Ageing Timer interrupt */ + ucr2 = imx_uart_readl(sport, UCR2); + ucr2 &= ~UCR2_ATEN; + imx_uart_writel(sport, ucr2, UCR2); + /* * In case RS485 is enabled without GPIO RTS control, the UART IP * is used to control CTS signal. Keep both the UART and Receiver