[PATCH v3 1/3] printk: Revert add_preferred_console_match() related commits

Tony Lindgren
2024-06-18T04:55:24Z

Recent changes to allow using DEVNAME:0.0 style console names caused a
regression to the kernel command line handling for the console options.

The last preferred console added gets used for init. This is documented
in the comments for add_preferred_console(). Now the kernel command line
options for console=ttyS0,115200 console=tty0 are wrongly handled and
cause the /dev/console to be associated with ttyS0 instead of tty0.

This happens because we are calling __add_preferred_console() later on
from serial8250_isa_init_ports() after console_setup() and the console
gets treated as the last added preferred console. As the DEVNAME:0.0 style
console device is not known at console_setup() time, I added a call to
__add_preferred_console() later on when the console is ready.

To fix the issue, let's revert the printk related commits:

f03e8c1060f8 ("printk: Save console options for add_preferred_console_match()")
b73c9cbe4f1f ("printk: Flag register_console() if console is set on command line")
8a831c584e6e ("printk: Don't try to parse DEVNAME:0.0 console options")

We need to also drop the call for add_preferred_console_match() from
serial_base_add_one_prefcon() added by commit 787a1cabac01 ("serial: core:
Add support for DEVNAME:0.0 style naming for kernel console").

Petr has suggested a better way to handle the deferred consoles that does
not rely on calling __add_preferred_console() again.

Reported-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/linux-serial/ZlC6_Um4P4b-_WQE@pathway.suse.cz/
Fixes: f03e8c1060f8 ("printk: Save console options for add_preferred_console_match()")
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Tony Lindgren <tony.lindgren@linux.intel.com>
---
drivers/tty/serial/serial_base_bus.c | 8 +-
include/linux/printk.h | 3 -
kernel/printk/Makefile | 2 +-
kernel/printk/conopt.c | 146 ---------------------------
kernel/printk/console_cmdline.h | 6 --
kernel/printk/printk.c | 23 +----
6 files changed, 6 insertions(+), 182 deletions(-)
delete mode 100644 kernel/printk/conopt.c

diff --git a/drivers/tty/serial/serial_base_bus.c b/drivers/tty/serial/serial_base_bus.c
index 73c6ee540c83..5ebacb982f9e 100644
--- a/drivers/tty/serial/serial_base_bus.c
+++ b/drivers/tty/serial/serial_base_bus.c
@@ -210,13 +210,7 @@ void serial_base_port_device_remove(struct serial_port_device *port_dev)
static int serial_base_add_one_prefcon(const char *match, const char *dev_name,
int port_id)
{
- int ret;
-
- ret = add_preferred_console_match(match, dev_name, port_id);
- if (ret == -ENOENT)
- return 0;
-
- return ret;
+ return 0;
}

#ifdef __sparc__
diff --git a/include/linux/printk.h b/include/linux/printk.h
index 40afab23881a..65c5184470f1 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -60,9 +60,6 @@ static inline const char *printk_skip_headers(const char *buffer)
#define CONSOLE_LOGLEVEL_DEFAULT CONFIG_CONSOLE_LOGLEVEL_DEFAULT
#define CONSOLE_LOGLEVEL_QUIET CONFIG_CONSOLE_LOGLEVEL_QUIET

-int add_preferred_console_match(const char *match, const char *name,
- const short idx);
-
extern int console_printk[];

#define console_loglevel (console_printk[0])
diff --git a/kernel/printk/Makefile b/kernel/printk/Makefile
index 040fe7d1eda2..39a2b61c7232 100644
--- a/kernel/printk/Makefile
+++ b/kernel/printk/Makefile
@@ -1,5 +1,5 @@
# SPDX-License-Identifier: GPL-2.0-only
-obj-y = printk.o conopt.o
+obj-y = printk.o
obj-$(CONFIG_PRINTK) += printk_safe.o nbcon.o
obj-$(CONFIG_A11Y_BRAILLE_CONSOLE) += braille.o
obj-$(CONFIG_PRINTK_INDEX) += index.o
diff --git a/kernel/printk/conopt.c b/kernel/printk/conopt.c
deleted file mode 100644
index 9d507bac3657..000000000000
--- a/kernel/printk/conopt.c
+++ /dev/null
@@ -1,146 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Kernel command line console options for hardware based addressing
- *
- * Copyright (C) 2023 Texas Instruments Incorporated - https://www.ti.com/
- * Author: Tony Lindgren <tony@atomide.com>
- */
-
-#include <linux/console.h>
-#include <linux/init.h>
-#include <linux/string.h>
-#include <linux/types.h>
-
-#include <asm/errno.h>
-
-#include "console_cmdline.h"
-
-/*
- * Allow longer DEVNAME:0.0 style console naming such as abcd0000.serial:0.0
- * in addition to the legacy ttyS0 style naming.
- */
-#define CONSOLE_NAME_MAX 32
-
-#define CONSOLE_OPT_MAX 16
-#define CONSOLE_BRL_OPT_MAX 16
-
-struct console_option {
- char name[CONSOLE_NAME_MAX];
- char opt[CONSOLE_OPT_MAX];
- char brl_opt[CONSOLE_BRL_OPT_MAX];
- u8 has_brl_opt:1;
-};
-
-/* Updated only at console_setup() time, no locking needed */
-static struct console_option conopt[MAX_CMDLINECONSOLES];
-
-/**
- * console_opt_save - Saves kernel command line console option for driver use
- * @str: Kernel command line console name and option
- * @brl_opt: Braille console options
- *
- * Saves a kernel command line console option for driver subsystems to use for
- * adding a preferred console during init. Called from console_setup() only.
- *
- * Return: 0 on success, negative error code on failure.
- */
-int __init console_opt_save(const char *str, const char *brl_opt)
-{
- struct console_option *con;
- size_t namelen, optlen;
- const char *opt;
- int i;
-
- namelen = strcspn(str, ",");
- if (namelen == 0 || namelen >= CONSOLE_NAME_MAX)
- return -EINVAL;
-
- opt = str + namelen;
- if (*opt == ',')
- opt++;
-
- optlen = strlen(opt);
- if (optlen >= CONSOLE_OPT_MAX)
- return -EINVAL;
-
- for (i = 0; i < MAX_CMDLINECONSOLES; i++) {
- con = &conopt[i];
-
- if (con->name[0]) {
- if (!strncmp(str, con->name, namelen))
- return 0;
- continue;
- }
-
- /*
- * The name isn't terminated, only opt is. Empty opt is fine,
- * but brl_opt can be either empty or NULL. For more info, see
- * _braille_console_setup().
- */
- strscpy(con->name, str, namelen + 1);
- strscpy(con->opt, opt, CONSOLE_OPT_MAX);
- if (brl_opt) {
- strscpy(con->brl_opt, brl_opt, CONSOLE_BRL_OPT_MAX);
- con->has_brl_opt = 1;
- }
-
- return 0;
- }
-
- return -ENOMEM;
-}
-
-static struct console_option *console_opt_find(const char *name)
-{
- struct console_option *con;
- int i;
-
- for (i = 0; i < MAX_CMDLINECONSOLES; i++) {
- con = &conopt[i];
- if (!strcmp(name, con->name))
- return con;
- }
-
- return NULL;
-}
-
-/**
- * add_preferred_console_match - Adds a preferred console if a match is found
- * @match: Expected console on kernel command line, such as console=DEVNAME:0.0
- * @name: Name of the console character device to add such as ttyS
- * @idx: Index for the console
- *
- * Allows driver subsystems to add a console after translating the command
- * line name to the character device name used for the console. Options are
- * added automatically based on the kernel command line. Duplicate preferred
- * consoles are ignored by __add_preferred_console().
- *
- * Return: 0 on success, negative error code on failure.
- */
-int add_preferred_console_match(const char *match, const char *name,
- const short idx)
-{
- struct console_option *con;
- char *brl_opt = NULL;
-
- if (!match || !strlen(match) || !name || !strlen(name) ||
- idx < 0)
- return -EINVAL;
-
- con = console_opt_find(match);
- if (!con)
- return -ENOENT;
-
- /*
- * See __add_preferred_console(). It checks for NULL brl_options to set
- * the preferred_console flag. Empty brl_opt instead of NULL leads into
- * the preferred_console flag not set, and CON_CONSDEV not being set,
- * and the boot console won't get disabled at the end of console_setup().
- */
- if (con->has_brl_opt)
- brl_opt = con->brl_opt;
-
- console_opt_add_preferred_console(name, idx, con->opt, brl_opt);
-
- return 0;
-}
diff --git a/kernel/printk/console_cmdline.h b/kernel/printk/console_cmdline.h
index a125e0235589..3ca74ad391d6 100644
--- a/kernel/printk/console_cmdline.h
+++ b/kernel/printk/console_cmdline.h
@@ -2,12 +2,6 @@
#ifndef _CONSOLE_CMDLINE_H
#define _CONSOLE_CMDLINE_H

-#define MAX_CMDLINECONSOLES 8
-
-int console_opt_save(const char *str, const char *brl_opt);
-int console_opt_add_preferred_console(const char *name, const short idx,
- char *options, char *brl_options);
-
struct console_cmdline
{
char name[16]; /* Name of the driver */
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 420fd310129d..dddb15f48d59 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -383,6 +383,9 @@ static int console_locked;
/*
* Array of consoles built from command line options (console=)
*/
+
+#define MAX_CMDLINECONSOLES 8
+
static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES];

static int preferred_console = -1;
@@ -2500,17 +2503,6 @@ static int __init console_setup(char *str)
if (_braille_console_setup(&str, &brl_options))
return 1;

- /* Save the console for driver subsystem use */
- if (console_opt_save(str, brl_options))
- return 1;
-
- /* Flag register_console() to not call try_enable_default_console() */
- console_set_on_cmdline = 1;
-
- /* Don't attempt to parse a DEVNAME:0.0 style console */
- if (strchr(str, ':'))
- return 1;
-
/*
* Decode str into name, index, options.
*/
@@ -2541,13 +2533,6 @@ static int __init console_setup(char *str)
}
__setup("console=", console_setup);

-/* Only called from add_preferred_console_match() */
-int console_opt_add_preferred_console(const char *name, const short idx,
- char *options, char *brl_options)
-{
- return __add_preferred_console(name, idx, options, brl_options, true);
-}
-
/**
* add_preferred_console - add a device to the list of preferred consoles.
* @name: device name
@@ -3522,7 +3507,7 @@ void register_console(struct console *newcon)
* Note that a console with tty binding will have CON_CONSDEV
* flag set and will be first in the list.
*/
- if (preferred_console < 0 && !console_set_on_cmdline) {
+ if (preferred_console < 0) {
if (hlist_empty(&console_list) || !console_first()->device ||
console_first()->flags & CON_BOOT) {
try_enable_default_console(newcon);
--
2.45.2