[PATCH v3 2/3] kgdb: Add command linux.vmcoreinfo to kgdb

[Amal Raj T <tjarlama@gmail.com>]

From: Amal Raj T <amalrajt@meta.com>

The current implementation of `poll_put_char` in the serial console driver
performs LF -> CRLF replacement, which can corrupt binary data. Since kdb
is the only user of `poll_put_char`, this patch moves the LF -> CRLF
replacement logic to kdb.

Link: https://lore.kernel.org/linux-debuggers/Zy093jVKPs9gSVx2@telecaster/
---
 drivers/tty/serial/serial_core.c | 2 --
 kernel/debug/kdb/kdb_io.c        | 2 ++
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 74fa02b23772..8e702f3deffb 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -2738,8 +2738,6 @@ static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
 	if (!port)
 		return;
 
-	if (ch == '\n')
-		port->ops->poll_put_char(port, '\r');
 	port->ops->poll_put_char(port, ch);
 	uart_port_deref(port);
 }
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 6a77f1c779c4..43a7c8ad741a 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -572,6 +572,8 @@ static void kdb_msg_write(const char *msg, int msg_len)
 	len = msg_len;
 
 	while (len--) {
+		if (*cp == '\n')
+			dbg_io_ops->write_char('\r');
 		dbg_io_ops->write_char(*cp);
 		cp++;
 	}
-- 
2.43.5