From: Ulrich Hecht uli+renesas@fpond.eu
stable inclusion from stable-5.10.67 commit 49e2bcb7cf580f83fec96b29bf2b3774bdf1b930 bugzilla: 182619 https://gitee.com/openeuler/kernel/issues/I4EWO7
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ Upstream commit 87b8061bad9bd4b549b2daf36ffbaa57be2789a2 ]
This fixes two issues that cause the sysrq sequence to be inadvertently aborted on SCIF serial consoles:
- a NUL character remains in the RX queue after a break has been detected, which is then passed on to uart_handle_sysrq_char() - the break interrupt is handled twice on controllers with multiplexed ERI and BRI interrupts
Signed-off-by: Ulrich Hecht uli+renesas@fpond.eu Link: https://lore.kernel.org/r/20210816162201.28801-1-uli+renesas@fpond.eu Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Chen Jun chenjun102@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com
Signed-off-by: Chen Jun chenjun102@huawei.com --- drivers/tty/serial/sh-sci.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 70898a999a49..f700bfaef129 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1760,6 +1760,10 @@ static irqreturn_t sci_br_interrupt(int irq, void *ptr)
/* Handle BREAKs */ sci_handle_breaks(port); + + /* drop invalid character received before break was detected */ + serial_port_in(port, SCxRDR); + sci_clear_SCxSR(port, SCxSR_BREAK_CLEAR(port));
return IRQ_HANDLED; @@ -1839,7 +1843,8 @@ static irqreturn_t sci_mpxed_interrupt(int irq, void *ptr) ret = sci_er_interrupt(irq, ptr);
/* Break Interrupt */ - if ((ssr_status & SCxSR_BRK(port)) && err_enabled) + if (s->irqs[SCIx_ERI_IRQ] != s->irqs[SCIx_BRI_IRQ] && + (ssr_status & SCxSR_BRK(port)) && err_enabled) ret = sci_br_interrupt(irq, ptr);
/* Overrun Interrupt */