2016-12-25 19:11:34 +00:00
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From: John Crispin <john@phrozen.org>
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Subject: serial: do not accept sysrq characters via serial port
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many embedded boards have a disconnected TTL level serial which can
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generate some garbage that can lead to spurious false sysrq detects.
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[john@phrozen.org: sent upstream 22.12.2016]
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Signed-off-by: John Crispin <john@phrozen.org>
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Signed-off-by: Felix Fietkau <nbd@nbd.name>
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---
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include/linux/serial_core.h | 2 +-
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lib/Kconfig.debug | 5 +++++
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2 files changed, 6 insertions(+), 1 deletion(-)
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--- a/include/linux/serial_core.h
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+++ b/include/linux/serial_core.h
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2018-05-17 16:41:25 +00:00
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@@ -455,7 +455,7 @@ extern void uart_handle_cts_change(struc
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2016-12-25 19:11:34 +00:00
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extern void uart_insert_char(struct uart_port *port, unsigned int status,
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unsigned int overrun, unsigned int ch, unsigned int flag);
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-#ifdef SUPPORT_SYSRQ
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+#if defined(SUPPORT_SYSRQ) && defined(CONFIG_MAGIC_SYSRQ_SERIAL)
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static inline int
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uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
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{
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--- a/lib/Kconfig.debug
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+++ b/lib/Kconfig.debug
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2018-06-06 13:22:05 +00:00
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@@ -396,6 +396,11 @@ config MAGIC_SYSRQ_DEFAULT_ENABLE
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2016-12-25 19:11:34 +00:00
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This may be set to 1 or 0 to enable or disable them all, or
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to a bitmask as described in Documentation/sysrq.txt.
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+config MAGIC_SYSRQ_SERIAL
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+ bool "Enable magic SysRq key over serial"
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+ depends on MAGIC_SYSRQ
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+ default y
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+
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config DEBUG_KERNEL
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bool "Kernel debugging"
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help
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