This is designed to be used in conjunction with
the boot argument: earlyprintk=vga
+ This parameter works in place of the kgdboc parameter
+ but can only be used if the backing tty is available
+ very early in the boot process. For early debugging
+ via a serial port see kgdboc_earlycon instead.
+
edd= [EDD]
Format: {"off" | "on" | "skip[mbr]"}
kms, kbd format: kms,kbd
kms, kbd and serial format: kms,kbd,<ser_dev>[,baud]
+ kgdboc_earlycon= [KGDB,HW]
+ If the boot console provides the ability to read
+ characters and can work in polling mode, you can use
+ this parameter to tell kgdb to use it as a backend
+ until the normal console is registered. Intended to
+ be used together with the kgdboc parameter which
+ specifies the normal console to transition to.
+
+ The name of the early console should be specified
+ as the value of this parameter. Note that the name of
+ the early console might be different than the tty
+ name passed to kgdboc. It's OK to leave the value
+ blank and the first boot console that implements
+ read() will be picked.
+
kgdbwait [KGDB] Stop kernel execution and enter the
kernel debugger at the earliest opportunity.
on the initial connect, or to use a debugger proxy that allows an
unmodified gdb to do the debugging.
+Kernel parameter: ``kgdboc_earlycon``
+-------------------------------------
+
+If you specify the kernel parameter ``kgdboc_earlycon`` and your serial
+driver registers a boot console that supports polling (doesn't need
+interrupts and implements a nonblocking read() function) kgdb will attempt
+to work using the boot console until it can transition to the regular
+tty driver specified by the ``kgdboc`` parameter.
+
+Normally there is only one boot console (especially that implements the
+read() function) so just adding ``kgdboc_earlycon`` on its own is
+sufficient to make this work. If you have more than one boot console you
+can add the boot console's name to differentiate. Note that names that
+are registered through the boot console layer and the tty layer are not
+the same for the same port.
+
+For instance, on one board to be explicit you might do::
+
+ kgdboc_earlycon=qcom_geni kgdboc=ttyMSM0
+
+If the only boot console on the device was "qcom_geni", you could simplify::
+
+ kgdboc_earlycon kgdboc=ttyMSM0
+
Kernel parameter: ``kgdbwait``
------------------------------
select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
select ARCH_HAS_DEBUG_VIRTUAL
select ARCH_HAS_DEVMEM_IS_ALLOWED
+ select ARCH_HAS_EARLY_DEBUG if KGDB
select ARCH_HAS_ELF_RANDOMIZE
select ARCH_HAS_FAST_MULTIPLIER
select ARCH_HAS_FILTER_PGPROT
uart_console_write(port, s, count, serial_putc);
}
+#ifdef CONFIG_CONSOLE_POLL
+static int early_serial8250_read(struct console *console,
+ char *s, unsigned int count)
+{
+ struct earlycon_device *device = console->data;
+ struct uart_port *port = &device->port;
+ unsigned int status;
+ int num_read = 0;
+
+ while (num_read < count) {
+ status = serial8250_early_in(port, UART_LSR);
+ if (!(status & UART_LSR_DR))
+ break;
+ s[num_read++] = serial8250_early_in(port, UART_RX);
+ }
+
+ return num_read;
+}
+#else
+#define early_serial8250_read NULL
+#endif
+
static void __init init_port(struct earlycon_device *device)
{
struct uart_port *port = &device->port;
init_port(device);
device->con->write = early_serial8250_write;
+ device->con->read = early_serial8250_read;
return 0;
}
EARLYCON_DECLARE(uart8250, early_serial8250_setup);
uart_console_write(&dev->port, s, n, pl011_putc);
}
+#ifdef CONFIG_CONSOLE_POLL
+static int pl011_getc(struct uart_port *port)
+{
+ if (readl(port->membase + UART01x_FR) & UART01x_FR_RXFE)
+ return NO_POLL_CHAR;
+
+ if (port->iotype == UPIO_MEM32)
+ return readl(port->membase + UART01x_DR);
+ else
+ return readb(port->membase + UART01x_DR);
+}
+
+static int pl011_early_read(struct console *con, char *s, unsigned int n)
+{
+ struct earlycon_device *dev = con->data;
+ int ch, num_read = 0;
+
+ while (num_read < n) {
+ ch = pl011_getc(&dev->port);
+ if (ch == NO_POLL_CHAR)
+ break;
+
+ s[num_read++] = ch;
+ }
+
+ return num_read;
+}
+#else
+#define pl011_early_read NULL
+#endif
+
/*
* On non-ACPI systems, earlycon is enabled by specifying
* "earlycon=pl011,<address>" on the kernel command line.
return -ENODEV;
device->con->write = pl011_early_write;
+ device->con->read = pl011_early_read;
return 0;
}
#include <linux/vt_kern.h>
#include <linux/input.h>
#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/serial_core.h>
#define MAX_CONFIG_LEN 40
/* -1 = init not run yet, 0 = unconfigured, 1 = configured. */
static int configured = -1;
+static DEFINE_MUTEX(config_mutex);
static char config[MAX_CONFIG_LEN];
static struct kparam_string kps = {
static struct tty_driver *kgdb_tty_driver;
static int kgdb_tty_line;
+static struct platform_device *kgdboc_pdev;
+
+#if IS_BUILTIN(CONFIG_KGDB_SERIAL_CONSOLE)
+static struct kgdb_io kgdboc_earlycon_io_ops;
+static struct console *earlycon;
+static int (*earlycon_orig_exit)(struct console *con);
+#endif /* IS_BUILTIN(CONFIG_KGDB_SERIAL_CONSOLE) */
+
#ifdef CONFIG_KDB_KEYBOARD
static int kgdboc_reset_connect(struct input_handler *handler,
struct input_dev *dev,
#define kgdboc_restore_input()
#endif /* ! CONFIG_KDB_KEYBOARD */
+#if IS_BUILTIN(CONFIG_KGDB_SERIAL_CONSOLE)
+static void cleanup_earlycon(void)
+{
+ if (earlycon)
+ kgdb_unregister_io_module(&kgdboc_earlycon_io_ops);
+}
+#else /* !IS_BUILTIN(CONFIG_KGDB_SERIAL_CONSOLE) */
+static inline void cleanup_earlycon(void) { }
+#endif /* !IS_BUILTIN(CONFIG_KGDB_SERIAL_CONSOLE) */
+
static void cleanup_kgdboc(void)
{
+ cleanup_earlycon();
+
+ if (configured != 1)
+ return;
+
if (kgdb_unregister_nmi_console())
return;
kgdboc_unregister_kbd();
- if (configured == 1)
- kgdb_unregister_io_module(&kgdboc_io_ops);
+ kgdb_unregister_io_module(&kgdboc_io_ops);
}
static int configure_kgdboc(void)
kgdb_unregister_io_module(&kgdboc_io_ops);
noconfig:
kgdboc_unregister_kbd();
- config[0] = 0;
configured = 0;
- cleanup_kgdboc();
return err;
}
+static int kgdboc_probe(struct platform_device *pdev)
+{
+ int ret = 0;
+
+ mutex_lock(&config_mutex);
+ if (configured != 1) {
+ ret = configure_kgdboc();
+
+ /* Convert "no device" to "defer" so we'll keep trying */
+ if (ret == -ENODEV)
+ ret = -EPROBE_DEFER;
+ }
+ mutex_unlock(&config_mutex);
+
+ return ret;
+}
+
+static struct platform_driver kgdboc_platform_driver = {
+ .probe = kgdboc_probe,
+ .driver = {
+ .name = "kgdboc",
+ .suppress_bind_attrs = true,
+ },
+};
+
static int __init init_kgdboc(void)
{
- /* Already configured? */
- if (configured == 1)
+ int ret;
+
+ /*
+ * kgdboc is a little bit of an odd "platform_driver". It can be
+ * up and running long before the platform_driver object is
+ * created and thus doesn't actually store anything in it. There's
+ * only one instance of kgdb so anything is stored as global state.
+ * The platform_driver is only created so that we can leverage the
+ * kernel's mechanisms (like -EPROBE_DEFER) to call us when our
+ * underlying tty is ready. Here we init our platform driver and
+ * then create the single kgdboc instance.
+ */
+ ret = platform_driver_register(&kgdboc_platform_driver);
+ if (ret)
+ return ret;
+
+ kgdboc_pdev = platform_device_alloc("kgdboc", PLATFORM_DEVID_NONE);
+ if (!kgdboc_pdev) {
+ ret = -ENOMEM;
+ goto err_did_register;
+ }
+
+ ret = platform_device_add(kgdboc_pdev);
+ if (!ret)
return 0;
- return configure_kgdboc();
+ platform_device_put(kgdboc_pdev);
+
+err_did_register:
+ platform_driver_unregister(&kgdboc_platform_driver);
+ return ret;
+}
+
+static void exit_kgdboc(void)
+{
+ mutex_lock(&config_mutex);
+ cleanup_kgdboc();
+ mutex_unlock(&config_mutex);
+
+ platform_device_unregister(kgdboc_pdev);
+ platform_driver_unregister(&kgdboc_platform_driver);
}
static int kgdboc_get_char(void)
const struct kernel_param *kp)
{
size_t len = strlen(kmessage);
+ int ret = 0;
if (len >= MAX_CONFIG_LEN) {
pr_err("config string too long\n");
return -ENOSPC;
}
- /* Only copy in the string if the init function has not run yet */
- if (configured < 0) {
- strcpy(config, kmessage);
- return 0;
- }
-
if (kgdb_connected) {
pr_err("Cannot reconfigure while KGDB is connected.\n");
-
return -EBUSY;
}
+ mutex_lock(&config_mutex);
+
strcpy(config, kmessage);
/* Chop out \n char as a result of echo */
if (len && config[len - 1] == '\n')
if (configured == 1)
cleanup_kgdboc();
- /* Go and configure with the new params. */
- return configure_kgdboc();
+ /*
+ * Configure with the new params as long as init already ran.
+ * Note that we can get called before init if someone loads us
+ * with "modprobe kgdboc kgdboc=..." or if they happen to use the
+ * the odd syntax of "kgdboc.kgdboc=..." on the kernel command.
+ */
+ if (configured >= 0)
+ ret = configure_kgdboc();
+
+ /*
+ * If we couldn't configure then clear out the config. Note that
+ * specifying an invalid config on the kernel command line vs.
+ * through sysfs have slightly different behaviors. If we fail
+ * to configure what was specified on the kernel command line
+ * we'll leave it in the 'config' and return -EPROBE_DEFER from
+ * our probe. When specified through sysfs userspace is
+ * responsible for loading the tty driver before setting up.
+ */
+ if (ret)
+ config[0] = '\0';
+
+ mutex_unlock(&config_mutex);
+
+ return ret;
}
static int dbg_restore_graphics;
/* Increment the module count when the debugger is active */
if (!kgdb_connected)
try_module_get(THIS_MODULE);
-
- atomic_inc(&ignore_console_lock_warning);
}
static void kgdboc_post_exp_handler(void)
{
- atomic_dec(&ignore_console_lock_warning);
-
/* decrement the module count when the debugger detaches */
if (!kgdb_connected)
module_put(THIS_MODULE);
.post_exception = kgdboc_post_exp_handler,
};
-#ifdef CONFIG_KGDB_SERIAL_CONSOLE
+#if IS_BUILTIN(CONFIG_KGDB_SERIAL_CONSOLE)
static int kgdboc_option_setup(char *opt)
{
if (!opt) {
/* This is only available if kgdboc is a built in for early debugging */
static int __init kgdboc_early_init(char *opt)
{
- /* save the first character of the config string because the
- * init routine can destroy it.
- */
- char save_ch;
-
kgdboc_option_setup(opt);
- save_ch = config[0];
- init_kgdboc();
- config[0] = save_ch;
+ configure_kgdboc();
return 0;
}
early_param("ekgdboc", kgdboc_early_init);
-#endif /* CONFIG_KGDB_SERIAL_CONSOLE */
+
+static int kgdboc_earlycon_get_char(void)
+{
+ char c;
+
+ if (!earlycon->read(earlycon, &c, 1))
+ return NO_POLL_CHAR;
+
+ return c;
+}
+
+static void kgdboc_earlycon_put_char(u8 chr)
+{
+ earlycon->write(earlycon, &chr, 1);
+}
+
+static void kgdboc_earlycon_pre_exp_handler(void)
+{
+ struct console *con;
+ static bool already_warned;
+
+ if (already_warned)
+ return;
+
+ /*
+ * When the first normal console comes up the kernel will take all
+ * the boot consoles out of the list. Really, we should stop using
+ * the boot console when it does that but until a TTY is registered
+ * we have no other choice so we keep using it. Since not all
+ * serial drivers might be OK with this, print a warning once per
+ * boot if we detect this case.
+ */
+ for_each_console(con)
+ if (con == earlycon)
+ return;
+
+ already_warned = true;
+ pr_warn("kgdboc_earlycon is still using bootconsole\n");
+}
+
+static int kgdboc_earlycon_deferred_exit(struct console *con)
+{
+ /*
+ * If we get here it means the boot console is going away but we
+ * don't yet have a suitable replacement. Don't pass through to
+ * the original exit routine. We'll call it later in our deinit()
+ * function. For now, restore the original exit() function pointer
+ * as a sentinal that we've hit this point.
+ */
+ con->exit = earlycon_orig_exit;
+
+ return 0;
+}
+
+static void kgdboc_earlycon_deinit(void)
+{
+ if (!earlycon)
+ return;
+
+ if (earlycon->exit == kgdboc_earlycon_deferred_exit)
+ /*
+ * kgdboc_earlycon is exiting but original boot console exit
+ * was never called (AKA kgdboc_earlycon_deferred_exit()
+ * didn't ever run). Undo our trap.
+ */
+ earlycon->exit = earlycon_orig_exit;
+ else if (earlycon->exit)
+ /*
+ * We skipped calling the exit() routine so we could try to
+ * keep using the boot console even after it went away. We're
+ * finally done so call the function now.
+ */
+ earlycon->exit(earlycon);
+
+ earlycon = NULL;
+}
+
+static struct kgdb_io kgdboc_earlycon_io_ops = {
+ .name = "kgdboc_earlycon",
+ .read_char = kgdboc_earlycon_get_char,
+ .write_char = kgdboc_earlycon_put_char,
+ .pre_exception = kgdboc_earlycon_pre_exp_handler,
+ .deinit = kgdboc_earlycon_deinit,
+ .is_console = true,
+};
+
+#define MAX_CONSOLE_NAME_LEN (sizeof((struct console *) 0)->name)
+static char kgdboc_earlycon_param[MAX_CONSOLE_NAME_LEN] __initdata;
+static bool kgdboc_earlycon_late_enable __initdata;
+
+static int __init kgdboc_earlycon_init(char *opt)
+{
+ struct console *con;
+
+ kdb_init(KDB_INIT_EARLY);
+
+ /*
+ * Look for a matching console, or if the name was left blank just
+ * pick the first one we find.
+ */
+ console_lock();
+ for_each_console(con) {
+ if (con->write && con->read &&
+ (con->flags & (CON_BOOT | CON_ENABLED)) &&
+ (!opt || !opt[0] || strcmp(con->name, opt) == 0))
+ break;
+ }
+
+ if (!con) {
+ /*
+ * Both earlycon and kgdboc_earlycon are initialized during * early parameter parsing. We cannot guarantee earlycon gets
+ * in first and, in any case, on ACPI systems earlycon may
+ * defer its own initialization (usually to somewhere within
+ * setup_arch() ). To cope with either of these situations
+ * we can defer our own initialization to a little later in
+ * the boot.
+ */
+ if (!kgdboc_earlycon_late_enable) {
+ pr_info("No suitable earlycon yet, will try later\n");
+ if (opt)
+ strscpy(kgdboc_earlycon_param, opt,
+ sizeof(kgdboc_earlycon_param));
+ kgdboc_earlycon_late_enable = true;
+ } else {
+ pr_info("Couldn't find kgdb earlycon\n");
+ }
+ goto unlock;
+ }
+
+ earlycon = con;
+ pr_info("Going to register kgdb with earlycon '%s'\n", con->name);
+ if (kgdb_register_io_module(&kgdboc_earlycon_io_ops) != 0) {
+ earlycon = NULL;
+ pr_info("Failed to register kgdb with earlycon\n");
+ } else {
+ /* Trap exit so we can keep earlycon longer if needed. */
+ earlycon_orig_exit = con->exit;
+ con->exit = kgdboc_earlycon_deferred_exit;
+ }
+
+unlock:
+ console_unlock();
+
+ /* Non-zero means malformed option so we always return zero */
+ return 0;
+}
+
+early_param("kgdboc_earlycon", kgdboc_earlycon_init);
+
+/*
+ * This is only intended for the late adoption of an early console.
+ *
+ * It is not a reliable way to adopt regular consoles because we can not
+ * control what order console initcalls are made and, in any case, many
+ * regular consoles are registered much later in the boot process than
+ * the console initcalls!
+ */
+static int __init kgdboc_earlycon_late_init(void)
+{
+ if (kgdboc_earlycon_late_enable)
+ kgdboc_earlycon_init(kgdboc_earlycon_param);
+ return 0;
+}
+console_initcall(kgdboc_earlycon_late_init);
+
+#endif /* IS_BUILTIN(CONFIG_KGDB_SERIAL_CONSOLE) */
module_init(init_kgdboc);
-module_exit(cleanup_kgdboc);
+module_exit(exit_kgdboc);
module_param_call(kgdboc, param_set_kgdboc_var, param_get_string, &kps, 0644);
MODULE_PARM_DESC(kgdboc, "<serial_device>[,baud]");
MODULE_DESCRIPTION("KGDB Console TTY Driver");
__qcom_geni_serial_console_write(&dev->port, s, n);
}
+#ifdef CONFIG_CONSOLE_POLL
+static int qcom_geni_serial_earlycon_read(struct console *con,
+ char *s, unsigned int n)
+{
+ struct earlycon_device *dev = con->data;
+ struct uart_port *uport = &dev->port;
+ int num_read = 0;
+ int ch;
+
+ while (num_read < n) {
+ ch = qcom_geni_serial_get_char(uport);
+ if (ch == NO_POLL_CHAR)
+ break;
+ s[num_read++] = ch;
+ }
+
+ return num_read;
+}
+
+static void __init qcom_geni_serial_enable_early_read(struct geni_se *se,
+ struct console *con)
+{
+ geni_se_setup_s_cmd(se, UART_START_READ, 0);
+ con->read = qcom_geni_serial_earlycon_read;
+}
+#else
+static inline void qcom_geni_serial_enable_early_read(struct geni_se *se,
+ struct console *con) { }
+#endif
+
static int __init qcom_geni_serial_earlycon_setup(struct earlycon_device *dev,
const char *opt)
{
dev->con->write = qcom_geni_serial_earlycon_write;
dev->con->setup = NULL;
+ qcom_geni_serial_enable_early_read(&se, dev->con);
+
return 0;
}
OF_EARLYCON_DECLARE(qcom_geni, "qcom,geni-debug-uart",
#define KDB_FLAG_NO_I8042 (1 << 7) /* No i8042 chip is available, do
* not use keyboard */
-extern int kdb_flags; /* Global flags, see kdb_state for per cpu state */
+extern unsigned int kdb_flags; /* Global flags, see kdb_state for per cpu state */
extern void kdb_save_flags(void);
extern void kdb_restore_flags(void);
* @write_char: Pointer to a function that will write one char.
* @flush: Pointer to a function that will flush any pending writes.
* @init: Pointer to a function that will initialize the device.
+ * @deinit: Pointer to a function that will deinit the device. Implies that
+ * this I/O driver is temporary and expects to be replaced. Called when
+ * an I/O driver is replaced or explicitly unregistered.
* @pre_exception: Pointer to a function that will do any prep work for
* the I/O driver.
* @post_exception: Pointer to a function that will do any cleanup work
void (*write_char) (u8);
void (*flush) (void);
int (*init) (void);
+ void (*deinit) (void);
void (*pre_exception) (void);
void (*post_exception) (void);
int is_console;
#else
static inline int kgdb_register_nmi_console(void) { return 0; }
static inline int kgdb_unregister_nmi_console(void) { return 0; }
-static inline bool kgdb_nmi_poll_knock(void) { return 1; }
+static inline bool kgdb_nmi_poll_knock(void) { return true; }
#endif
extern int kgdb_register_io_module(struct kgdb_io *local_kgdb_io_ops);
extern int kgdb_single_step;
extern atomic_t kgdb_active;
#define in_dbg_master() \
- (raw_smp_processor_id() == atomic_read(&kgdb_active))
+ (irqs_disabled() && (smp_processor_id() == atomic_read(&kgdb_active)))
extern bool dbg_is_early;
extern void __init dbg_late_init(void);
extern void kgdb_panic(const char *msg);
struct debuggerinfo_struct kgdb_info[NR_CPUS];
-/**
- * kgdb_connected - Is a host GDB connected to us?
- */
+/* kgdb_connected - Is a host GDB connected to us? */
int kgdb_connected;
EXPORT_SYMBOL_GPL(kgdb_connected);
if (exception_level > 1) {
dump_stack();
+ kgdb_io_module_registered = false;
panic("Recursive entry to debugger");
}
if (kgdb_skipexception(ks->ex_vector, ks->linux_regs))
goto kgdb_restore;
+ atomic_inc(&ignore_console_lock_warning);
+
/* Call the I/O driver's pre_exception routine */
if (dbg_io_ops->pre_exception)
dbg_io_ops->pre_exception();
if (dbg_io_ops->post_exception)
dbg_io_ops->post_exception();
+ atomic_dec(&ignore_console_lock_warning);
+
if (!kgdb_single_step) {
raw_spin_unlock(&dbg_slave_lock);
/* Wait till all the CPUs have quit from the debugger. */
kgdb_breakpoint();
}
+static void kgdb_initial_breakpoint(void)
+{
+ kgdb_break_asap = 0;
+
+ pr_crit("Waiting for connection from remote gdb...\n");
+ kgdb_breakpoint();
+}
+
void __weak kgdb_arch_late(void)
{
}
if (kgdb_io_module_registered)
kgdb_arch_late();
kdb_init(KDB_INIT_FULL);
+
+ if (kgdb_io_module_registered && kgdb_break_asap)
+ kgdb_initial_breakpoint();
}
static int
}
EXPORT_SYMBOL_GPL(kgdb_schedule_breakpoint);
-static void kgdb_initial_breakpoint(void)
-{
- kgdb_break_asap = 0;
-
- pr_crit("Waiting for connection from remote gdb...\n");
- kgdb_breakpoint();
-}
-
/**
* kgdb_register_io_module - register KGDB IO module
* @new_dbg_io_ops: the io ops vector
*/
int kgdb_register_io_module(struct kgdb_io *new_dbg_io_ops)
{
+ struct kgdb_io *old_dbg_io_ops;
int err;
spin_lock(&kgdb_registration_lock);
- if (dbg_io_ops) {
- spin_unlock(&kgdb_registration_lock);
+ old_dbg_io_ops = dbg_io_ops;
+ if (old_dbg_io_ops) {
+ if (!old_dbg_io_ops->deinit) {
+ spin_unlock(&kgdb_registration_lock);
- pr_err("Another I/O driver is already registered with KGDB\n");
- return -EBUSY;
+ pr_err("KGDB I/O driver %s can't replace %s.\n",
+ new_dbg_io_ops->name, old_dbg_io_ops->name);
+ return -EBUSY;
+ }
+ pr_info("Replacing I/O driver %s with %s\n",
+ old_dbg_io_ops->name, new_dbg_io_ops->name);
}
if (new_dbg_io_ops->init) {
spin_unlock(&kgdb_registration_lock);
+ if (old_dbg_io_ops) {
+ old_dbg_io_ops->deinit();
+ return 0;
+ }
+
pr_info("Registered I/O driver %s\n", new_dbg_io_ops->name);
/* Arm KGDB now. */
kgdb_register_callbacks();
- if (kgdb_break_asap)
+ if (kgdb_break_asap &&
+ (!dbg_is_early || IS_ENABLED(CONFIG_ARCH_HAS_EARLY_DEBUG)))
kgdb_initial_breakpoint();
return 0;
spin_unlock(&kgdb_registration_lock);
+ if (old_dbg_io_ops->deinit)
+ old_dbg_io_ops->deinit();
+
pr_info("Unregistered I/O driver %s, debugger disabled\n",
old_dbg_io_ops->name);
}
kgdb_break_asap = 1;
kdb_init(KDB_INIT_EARLY);
- if (kgdb_io_module_registered)
+ if (kgdb_io_module_registered &&
+ IS_ENABLED(CONFIG_ARCH_HAS_EARLY_DEBUG))
kgdb_initial_breakpoint();
return 0;
/*
* Kernel debugger state flags
*/
-int kdb_flags;
+unsigned int kdb_flags;
/*
* kdb_lock protects updates to kdb_initial_cpu. Used to
argv[2]);
return 0;
}
- kdb_flags = (kdb_flags &
- ~(KDB_DEBUG_FLAG_MASK << KDB_DEBUG_FLAG_SHIFT))
+ kdb_flags = (kdb_flags & ~KDB_DEBUG(MASK))
| (debugflags << KDB_DEBUG_FLAG_SHIFT);
return 0;
switch (*cmd) {
case CTRL_P:
if (cmdptr != cmd_tail)
- cmdptr = (cmdptr-1) % KDB_CMD_HISTORY_COUNT;
+ cmdptr = (cmdptr + KDB_CMD_HISTORY_COUNT - 1) %
+ KDB_CMD_HISTORY_COUNT;
strscpy(cmd_cur, cmd_hist[cmdptr], CMD_BUFLEN);
return 1;
case CTRL_N:
}
if (KDB_DEBUG(MASK))
- kdb_printf("KDBFLAGS=0x%x\n", kdb_flags);
+ kdb_printf("KDBDEBUG=0x%x\n",
+ (kdb_flags & KDB_DEBUG(MASK)) >> KDB_DEBUG_FLAG_SHIFT);
return 0;
}
CONFIG_KDB_CONTINUE_CATASTROPHIC == 2. KDB forces a reboot.
If you are not sure, say 0.
+config ARCH_HAS_EARLY_DEBUG
+ bool
+ default n
+ help
+ If an architecture can definitely handle entering the debugger
+ when early_param's are parsed then it select this config.
+ Otherwise, if "kgdbwait" is passed on the kernel command line it
+ won't actually be processed until dbg_late_init() just after the
+ call to kgdb_arch_late() is made.
+
+ NOTE: Even if this isn't selected by an architecture we will
+ still try to register kgdb to handle breakpoints and crashes
+ when early_param's are parsed, we just won't act on the
+ "kgdbwait" parameter until dbg_late_init(). If you get a
+ crash and try to drop into kgdb somewhere between these two
+ places you might or might not end up being able to use kgdb
+ depending on exactly how far along the architecture has initted.
+
endif # KGDB
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