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Revert "tty/serial: Add kgdb_nmi driver"
This reverts commit0c57dfcc6c. The functionality was supoosed to be used by a later patch in the series that never landed [1]. Drop it. NOTE: part of functionality was already reverted by commit39d0be8743("serial: kgdb_nmi: Remove unused knock code"). Also note that this revert is not a clean revert given code changes that have happened in the meantime. It's obvious that nobody is using this code since the two exposed functions (kgdb_register_nmi_console() and kgdb_unregister_nmi_console()) are both no-ops if "arch_kgdb_ops.enable_nmi" is not defined. No architectures define it. [1] https://lore.kernel.org/lkml/1348522080-32629-9-git-send-email-anton.vorontsov@linaro.org/ Signed-off-by: Douglas Anderson <dianders@chromium.org> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: URL [1] Link: https://lore.kernel.org/r/20250129082535.1.Ia095eac1ae357f87d23e7af2206741f5d40788f1@changeid Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Douglas Anderson
Greg Kroah-Hartman
parent
c213375e32
commit
c08b0f2c31
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@ -179,25 +179,6 @@ config SERIAL_ATMEL_TTYAT
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Say Y if you have an external 8250/16C550 UART. If unsure, say N.
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config SERIAL_KGDB_NMI
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bool "Serial console over KGDB NMI debugger port"
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depends on KGDB_SERIAL_CONSOLE
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help
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This special driver allows you to temporary use NMI debugger port
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as a normal console (assuming that the port is attached to KGDB).
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Unlike KDB's disable_nmi command, with this driver you are always
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able to go back to the debugger using KGDB escape sequence ($3#33).
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This is because this console driver processes the input in NMI
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context, and thus is able to intercept the magic sequence.
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Note that since the console interprets input and uses polling
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communication methods, for things like PPP you still must fully
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detach debugger port from the KGDB NMI (i.e. disable_nmi), and
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use raw console.
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If unsure, say N.
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config SERIAL_MESON
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tristate "Meson serial port support"
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depends on ARCH_MESON || COMPILE_TEST
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@ -96,6 +96,5 @@ obj-$(CONFIG_SERIAL_ZS) += zs.o
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# GPIOLIB helpers for modem control lines
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obj-$(CONFIG_SERIAL_MCTRL_GPIO) += serial_mctrl_gpio.o
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obj-$(CONFIG_SERIAL_KGDB_NMI) += kgdb_nmi.o
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obj-$(CONFIG_KGDB_SERIAL_CONSOLE) += kgdboc.o
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obj-$(CONFIG_SERIAL_NUVOTON_MA35D1) += ma35d1_serial.o
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@ -1,280 +0,0 @@
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// SPDX-License-Identifier: GPL-2.0
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/*
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* KGDB NMI serial console
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*
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* Copyright 2010 Google, Inc.
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* Arve Hjønnevåg <arve@android.com>
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* Colin Cross <ccross@android.com>
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* Copyright 2012 Linaro Ltd.
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* Anton Vorontsov <anton.vorontsov@linaro.org>
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/compiler.h>
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#include <linux/slab.h>
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#include <linux/errno.h>
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#include <linux/atomic.h>
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#include <linux/console.h>
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#include <linux/tty.h>
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#include <linux/tty_driver.h>
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#include <linux/tty_flip.h>
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#include <linux/serial_core.h>
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#include <linux/interrupt.h>
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#include <linux/hrtimer.h>
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#include <linux/tick.h>
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#include <linux/kfifo.h>
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#include <linux/kgdb.h>
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#include <linux/kdb.h>
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static atomic_t kgdb_nmi_num_readers = ATOMIC_INIT(0);
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static int kgdb_nmi_console_setup(struct console *co, char *options)
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{
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arch_kgdb_ops.enable_nmi(1);
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/* The NMI console uses the dbg_io_ops to issue console messages. To
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* avoid duplicate messages during kdb sessions we must inform kdb's
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* I/O utilities that messages sent to the console will automatically
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* be displayed on the dbg_io.
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*/
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dbg_io_ops->cons = co;
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return 0;
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}
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static void kgdb_nmi_console_write(struct console *co, const char *s, uint c)
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{
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int i;
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for (i = 0; i < c; i++)
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dbg_io_ops->write_char(s[i]);
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}
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static struct tty_driver *kgdb_nmi_tty_driver;
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static struct tty_driver *kgdb_nmi_console_device(struct console *co, int *idx)
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{
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*idx = co->index;
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return kgdb_nmi_tty_driver;
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}
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static struct console kgdb_nmi_console = {
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.name = "ttyNMI",
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.setup = kgdb_nmi_console_setup,
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.write = kgdb_nmi_console_write,
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.device = kgdb_nmi_console_device,
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.flags = CON_PRINTBUFFER | CON_ANYTIME,
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.index = -1,
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};
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/*
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* This is usually the maximum rate on debug ports. We make fifo large enough
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* to make copy-pasting to the terminal usable.
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*/
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#define KGDB_NMI_BAUD 115200
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#define KGDB_NMI_FIFO_SIZE roundup_pow_of_two(KGDB_NMI_BAUD / 8 / HZ)
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struct kgdb_nmi_tty_priv {
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struct tty_port port;
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struct timer_list timer;
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STRUCT_KFIFO(char, KGDB_NMI_FIFO_SIZE) fifo;
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};
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static struct tty_port *kgdb_nmi_port;
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/*
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* The tasklet is cheap, it does not cause wakeups when reschedules itself,
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* instead it waits for the next tick.
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*/
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static void kgdb_nmi_tty_receiver(struct timer_list *t)
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{
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struct kgdb_nmi_tty_priv *priv = from_timer(priv, t, timer);
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char ch;
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priv->timer.expires = jiffies + (HZ/100);
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add_timer(&priv->timer);
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if (likely(!atomic_read(&kgdb_nmi_num_readers) ||
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!kfifo_len(&priv->fifo)))
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return;
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while (kfifo_out(&priv->fifo, &ch, 1))
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tty_insert_flip_char(&priv->port, ch, TTY_NORMAL);
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tty_flip_buffer_push(&priv->port);
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}
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static int kgdb_nmi_tty_activate(struct tty_port *port, struct tty_struct *tty)
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{
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struct kgdb_nmi_tty_priv *priv =
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container_of(port, struct kgdb_nmi_tty_priv, port);
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kgdb_nmi_port = port;
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priv->timer.expires = jiffies + (HZ/100);
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add_timer(&priv->timer);
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return 0;
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}
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static void kgdb_nmi_tty_shutdown(struct tty_port *port)
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{
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struct kgdb_nmi_tty_priv *priv =
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container_of(port, struct kgdb_nmi_tty_priv, port);
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del_timer(&priv->timer);
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kgdb_nmi_port = NULL;
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}
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static const struct tty_port_operations kgdb_nmi_tty_port_ops = {
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.activate = kgdb_nmi_tty_activate,
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.shutdown = kgdb_nmi_tty_shutdown,
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};
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static int kgdb_nmi_tty_install(struct tty_driver *drv, struct tty_struct *tty)
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{
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struct kgdb_nmi_tty_priv *priv;
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int ret;
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priv = kzalloc(sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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INIT_KFIFO(priv->fifo);
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timer_setup(&priv->timer, kgdb_nmi_tty_receiver, 0);
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tty_port_init(&priv->port);
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priv->port.ops = &kgdb_nmi_tty_port_ops;
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tty->driver_data = priv;
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ret = tty_port_install(&priv->port, drv, tty);
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if (ret) {
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pr_err("%s: can't install tty port: %d\n", __func__, ret);
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goto err;
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}
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return 0;
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err:
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tty_port_destroy(&priv->port);
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kfree(priv);
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return ret;
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}
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static void kgdb_nmi_tty_cleanup(struct tty_struct *tty)
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{
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struct kgdb_nmi_tty_priv *priv = tty->driver_data;
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tty->driver_data = NULL;
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tty_port_destroy(&priv->port);
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kfree(priv);
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}
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static int kgdb_nmi_tty_open(struct tty_struct *tty, struct file *file)
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{
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struct kgdb_nmi_tty_priv *priv = tty->driver_data;
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unsigned int mode = file->f_flags & O_ACCMODE;
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int ret;
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ret = tty_port_open(&priv->port, tty, file);
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if (!ret && (mode == O_RDONLY || mode == O_RDWR))
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atomic_inc(&kgdb_nmi_num_readers);
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return ret;
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}
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static void kgdb_nmi_tty_close(struct tty_struct *tty, struct file *file)
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{
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struct kgdb_nmi_tty_priv *priv = tty->driver_data;
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unsigned int mode = file->f_flags & O_ACCMODE;
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if (mode == O_RDONLY || mode == O_RDWR)
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atomic_dec(&kgdb_nmi_num_readers);
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tty_port_close(&priv->port, tty, file);
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}
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static void kgdb_nmi_tty_hangup(struct tty_struct *tty)
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{
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struct kgdb_nmi_tty_priv *priv = tty->driver_data;
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tty_port_hangup(&priv->port);
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}
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static unsigned int kgdb_nmi_tty_write_room(struct tty_struct *tty)
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{
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/* Actually, we can handle any amount as we use polled writes. */
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return 2048;
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}
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static ssize_t kgdb_nmi_tty_write(struct tty_struct *tty, const u8 *buf,
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size_t c)
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{
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int i;
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for (i = 0; i < c; i++)
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dbg_io_ops->write_char(buf[i]);
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return c;
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}
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static const struct tty_operations kgdb_nmi_tty_ops = {
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.open = kgdb_nmi_tty_open,
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.close = kgdb_nmi_tty_close,
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.install = kgdb_nmi_tty_install,
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.cleanup = kgdb_nmi_tty_cleanup,
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.hangup = kgdb_nmi_tty_hangup,
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.write_room = kgdb_nmi_tty_write_room,
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.write = kgdb_nmi_tty_write,
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};
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int kgdb_register_nmi_console(void)
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{
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int ret;
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if (!arch_kgdb_ops.enable_nmi)
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return 0;
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kgdb_nmi_tty_driver = tty_alloc_driver(1, TTY_DRIVER_REAL_RAW);
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if (IS_ERR(kgdb_nmi_tty_driver)) {
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pr_err("%s: cannot allocate tty\n", __func__);
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return PTR_ERR(kgdb_nmi_tty_driver);
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}
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kgdb_nmi_tty_driver->driver_name = "ttyNMI";
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kgdb_nmi_tty_driver->name = "ttyNMI";
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kgdb_nmi_tty_driver->num = 1;
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kgdb_nmi_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
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kgdb_nmi_tty_driver->subtype = SERIAL_TYPE_NORMAL;
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kgdb_nmi_tty_driver->init_termios = tty_std_termios;
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tty_termios_encode_baud_rate(&kgdb_nmi_tty_driver->init_termios,
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KGDB_NMI_BAUD, KGDB_NMI_BAUD);
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tty_set_operations(kgdb_nmi_tty_driver, &kgdb_nmi_tty_ops);
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ret = tty_register_driver(kgdb_nmi_tty_driver);
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if (ret) {
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pr_err("%s: can't register tty driver: %d\n", __func__, ret);
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goto err_drv_reg;
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}
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register_console(&kgdb_nmi_console);
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return 0;
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err_drv_reg:
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tty_driver_kref_put(kgdb_nmi_tty_driver);
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return ret;
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}
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EXPORT_SYMBOL_GPL(kgdb_register_nmi_console);
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int kgdb_unregister_nmi_console(void)
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{
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int ret;
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if (!arch_kgdb_ops.enable_nmi)
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return 0;
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arch_kgdb_ops.enable_nmi(0);
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ret = unregister_console(&kgdb_nmi_console);
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if (ret)
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return ret;
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tty_unregister_driver(kgdb_nmi_tty_driver);
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tty_driver_kref_put(kgdb_nmi_tty_driver);
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return 0;
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}
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EXPORT_SYMBOL_GPL(kgdb_unregister_nmi_console);
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@ -186,8 +186,6 @@ static void cleanup_kgdboc(void)
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if (configured != 1)
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return;
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if (kgdb_unregister_nmi_console())
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return;
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kgdboc_unregister_kbd();
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kgdb_unregister_io_module(&kgdboc_io_ops);
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}
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@ -250,16 +248,10 @@ static int configure_kgdboc(void)
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if (err)
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goto noconfig;
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err = kgdb_register_nmi_console();
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if (err)
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goto nmi_con_failed;
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configured = 1;
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return 0;
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nmi_con_failed:
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kgdb_unregister_io_module(&kgdboc_io_ops);
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noconfig:
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kgdboc_unregister_kbd();
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configured = 0;
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@ -306,14 +306,6 @@ extern const struct kgdb_arch arch_kgdb_ops;
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extern unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs);
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#ifdef CONFIG_SERIAL_KGDB_NMI
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extern int kgdb_register_nmi_console(void);
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extern int kgdb_unregister_nmi_console(void);
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#else
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static inline int kgdb_register_nmi_console(void) { return 0; }
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static inline int kgdb_unregister_nmi_console(void) { return 0; }
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#endif
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extern int kgdb_register_io_module(struct kgdb_io *local_kgdb_io_ops);
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extern void kgdb_unregister_io_module(struct kgdb_io *local_kgdb_io_ops);
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extern struct kgdb_io *dbg_io_ops;
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