aboutsummaryrefslogtreecommitdiffstatshomepage
path: root/include/linux/console.h
diff options
context:
space:
mode:
Diffstat (limited to 'include/linux/console.h')
-rw-r--r--include/linux/console.h628
1 files changed, 535 insertions, 93 deletions
diff --git a/include/linux/console.h b/include/linux/console.h
index 4b1e26c4cb42..8f10d0a85bb4 100644
--- a/include/linux/console.h
+++ b/include/linux/console.h
@@ -15,7 +15,12 @@
#define _LINUX_CONSOLE_H_ 1
#include <linux/atomic.h>
+#include <linux/bits.h>
+#include <linux/irq_work.h>
+#include <linux/rculist.h>
+#include <linux/rcuwait.h>
#include <linux/types.h>
+#include <linux/vesa.h>
struct vc_data;
struct console_font_op;
@@ -34,63 +39,91 @@ enum vc_intensity;
/**
* struct consw - callbacks for consoles
*
+ * @owner: the module to get references of when this console is used
+ * @con_startup: set up the console and return its name (like VGA, EGA, ...)
+ * @con_init: initialize the console on @vc. @init is true for the very first
+ * call on this @vc.
+ * @con_deinit: deinitialize the console from @vc.
+ * @con_clear: erase @count characters at [@x, @y] on @vc. @count >= 1.
+ * @con_putc: emit one character with attributes @ca to [@x, @y] on @vc.
+ * (optional -- @con_putcs would be called instead)
+ * @con_putcs: emit @count characters with attributes @s to [@x, @y] on @vc.
+ * @con_cursor: enable/disable cursor depending on @enable
* @con_scroll: move lines from @top to @bottom in direction @dir by @lines.
* Return true if no generic handling should be done.
* Invoked by csi_M and printing to the console.
- * @con_set_palette: sets the palette of the console to @table (optional)
+ * @con_switch: notifier about the console switch; it is supposed to return
+ * true if a redraw is needed.
+ * @con_blank: blank/unblank the console. The target mode is passed in @blank.
+ * @mode_switch is set if changing from/to text/graphics. The hook
+ * is supposed to return true if a redraw is needed.
+ * @con_font_set: set console @vc font to @font with height @vpitch. @flags can
+ * be %KD_FONT_FLAG_DONT_RECALC. (optional)
+ * @con_font_get: fetch the current font on @vc of height @vpitch into @font.
+ * (optional)
+ * @con_font_default: set default font on @vc. @name can be %NULL or font name
+ * to search for. @font can be filled back. (optional)
+ * @con_resize: resize the @vc console to @width x @height. @from_user is true
+ * when this change comes from the user space.
+ * @con_set_palette: sets the palette of the console @vc to @table (optional)
* @con_scrolldelta: the contents of the console should be scrolled by @lines.
* Invoked by user. (optional)
+ * @con_set_origin: set origin (see &vc_data::vc_origin) of the @vc. If not
+ * provided or returns false, the origin is set to
+ * @vc->vc_screenbuf. (optional)
+ * @con_save_screen: save screen content into @vc->vc_screenbuf. Called e.g.
+ * upon entering graphics. (optional)
+ * @con_build_attr: build attributes based on @color, @intensity and other
+ * parameters. The result is used for both normal and erase
+ * characters. (optional)
+ * @con_invert_region: invert a region of length @count on @vc starting at @p.
+ * (optional)
+ * @con_debug_enter: prepare the console for the debugger. This includes, but
+ * is not limited to, unblanking the console, loading an
+ * appropriate palette, and allowing debugger generated output.
+ * (optional)
+ * @con_debug_leave: restore the console to its pre-debug state as closely as
+ * possible. (optional)
*/
struct consw {
struct module *owner;
const char *(*con_startup)(void);
- void (*con_init)(struct vc_data *vc, int init);
+ void (*con_init)(struct vc_data *vc, bool init);
void (*con_deinit)(struct vc_data *vc);
- void (*con_clear)(struct vc_data *vc, int sy, int sx, int height,
- int width);
- void (*con_putc)(struct vc_data *vc, int c, int ypos, int xpos);
- void (*con_putcs)(struct vc_data *vc, const unsigned short *s,
- int count, int ypos, int xpos);
- void (*con_cursor)(struct vc_data *vc, int mode);
+ void (*con_clear)(struct vc_data *vc, unsigned int y,
+ unsigned int x, unsigned int count);
+ void (*con_putc)(struct vc_data *vc, u16 ca, unsigned int y,
+ unsigned int x);
+ void (*con_putcs)(struct vc_data *vc, const u16 *s,
+ unsigned int count, unsigned int ypos,
+ unsigned int xpos);
+ void (*con_cursor)(struct vc_data *vc, bool enable);
bool (*con_scroll)(struct vc_data *vc, unsigned int top,
unsigned int bottom, enum con_scroll dir,
unsigned int lines);
- int (*con_switch)(struct vc_data *vc);
- int (*con_blank)(struct vc_data *vc, int blank, int mode_switch);
- int (*con_font_set)(struct vc_data *vc, struct console_font *font,
- unsigned int flags);
- int (*con_font_get)(struct vc_data *vc, struct console_font *font);
+ bool (*con_switch)(struct vc_data *vc);
+ bool (*con_blank)(struct vc_data *vc, enum vesa_blank_mode blank,
+ bool mode_switch);
+ int (*con_font_set)(struct vc_data *vc,
+ const struct console_font *font,
+ unsigned int vpitch, unsigned int flags);
+ int (*con_font_get)(struct vc_data *vc, struct console_font *font,
+ unsigned int vpitch);
int (*con_font_default)(struct vc_data *vc,
- struct console_font *font, char *name);
- int (*con_font_copy)(struct vc_data *vc, int con);
+ struct console_font *font, const char *name);
int (*con_resize)(struct vc_data *vc, unsigned int width,
- unsigned int height, unsigned int user);
+ unsigned int height, bool from_user);
void (*con_set_palette)(struct vc_data *vc,
const unsigned char *table);
void (*con_scrolldelta)(struct vc_data *vc, int lines);
- int (*con_set_origin)(struct vc_data *vc);
+ bool (*con_set_origin)(struct vc_data *vc);
void (*con_save_screen)(struct vc_data *vc);
u8 (*con_build_attr)(struct vc_data *vc, u8 color,
enum vc_intensity intensity,
bool blink, bool underline, bool reverse, bool italic);
void (*con_invert_region)(struct vc_data *vc, u16 *p, int count);
- u16 *(*con_screen_pos)(const struct vc_data *vc, int offset);
- unsigned long (*con_getxy)(struct vc_data *vc, unsigned long position,
- int *px, int *py);
- /*
- * Flush the video console driver's scrollback buffer
- */
- void (*con_flush_scrollback)(struct vc_data *vc);
- /*
- * Prepare the console for the debugger. This includes, but is not
- * limited to, unblanking the console, loading an appropriate
- * palette, and allowing debugger generated output.
- */
- int (*con_debug_enter)(struct vc_data *vc);
- /*
- * Restore the console to its pre-debug state as closely as possible.
- */
- int (*con_debug_leave)(struct vc_data *vc);
+ void (*con_debug_enter)(struct vc_data *vc);
+ void (*con_debug_leave)(struct vc_data *vc);
};
extern const struct consw *conswitchp;
@@ -99,66 +132,487 @@ extern const struct consw dummy_con; /* dummy console buffer */
extern const struct consw vga_con; /* VGA text console */
extern const struct consw newport_con; /* SGI Newport console */
+struct screen_info;
+#ifdef CONFIG_VGA_CONSOLE
+void vgacon_register_screen(struct screen_info *si);
+#else
+static inline void vgacon_register_screen(struct screen_info *si) { }
+#endif
+
int con_is_bound(const struct consw *csw);
int do_unregister_con_driver(const struct consw *csw);
int do_take_over_console(const struct consw *sw, int first, int last, int deflt);
void give_up_console(const struct consw *sw);
-#ifdef CONFIG_HW_CONSOLE
-int con_debug_enter(struct vc_data *vc);
-int con_debug_leave(void);
+#ifdef CONFIG_VT
+void con_debug_enter(struct vc_data *vc);
+void con_debug_leave(void);
#else
-static inline int con_debug_enter(struct vc_data *vc)
-{
- return 0;
-}
-static inline int con_debug_leave(void)
-{
- return 0;
-}
+static inline void con_debug_enter(struct vc_data *vc) { }
+static inline void con_debug_leave(void) { }
#endif
-/* cursor */
-#define CM_DRAW (1)
-#define CM_ERASE (2)
-#define CM_MOVE (3)
-
/*
* The interface for a console, or any other device that wants to capture
* console messages (printer driver?)
+ */
+
+/**
+ * enum cons_flags - General console flags
+ * @CON_PRINTBUFFER: Used by newly registered consoles to avoid duplicate
+ * output of messages that were already shown by boot
+ * consoles or read by userspace via syslog() syscall.
+ * @CON_CONSDEV: Indicates that the console driver is backing
+ * /dev/console.
+ * @CON_ENABLED: Indicates if a console is allowed to print records. If
+ * false, the console also will not advance to later
+ * records.
+ * @CON_BOOT: Marks the console driver as early console driver which
+ * is used during boot before the real driver becomes
+ * available. It will be automatically unregistered
+ * when the real console driver is registered unless
+ * "keep_bootcon" parameter is used.
+ * @CON_ANYTIME: A misnomed historical flag which tells the core code
+ * that the legacy @console::write callback can be invoked
+ * on a CPU which is marked OFFLINE. That is misleading as
+ * it suggests that there is no contextual limit for
+ * invoking the callback. The original motivation was
+ * readiness of the per-CPU areas.
+ * @CON_BRL: Indicates a braille device which is exempt from
+ * receiving the printk spam for obvious reasons.
+ * @CON_EXTENDED: The console supports the extended output format of
+ * /dev/kmesg which requires a larger output buffer.
+ * @CON_SUSPENDED: Indicates if a console is suspended. If true, the
+ * printing callbacks must not be called.
+ * @CON_NBCON: Console can operate outside of the legacy style console_lock
+ * constraints.
+ */
+enum cons_flags {
+ CON_PRINTBUFFER = BIT(0),
+ CON_CONSDEV = BIT(1),
+ CON_ENABLED = BIT(2),
+ CON_BOOT = BIT(3),
+ CON_ANYTIME = BIT(4),
+ CON_BRL = BIT(5),
+ CON_EXTENDED = BIT(6),
+ CON_SUSPENDED = BIT(7),
+ CON_NBCON = BIT(8),
+};
+
+/**
+ * struct nbcon_state - console state for nbcon consoles
+ * @atom: Compound of the state fields for atomic operations
+ *
+ * @req_prio: The priority of a handover request
+ * @prio: The priority of the current owner
+ * @unsafe: Console is busy in a non takeover region
+ * @unsafe_takeover: A hostile takeover in an unsafe state happened in the
+ * past. The console cannot be safe until re-initialized.
+ * @cpu: The CPU on which the owner runs
+ *
+ * To be used for reading and preparing of the value stored in the nbcon
+ * state variable @console::nbcon_state.
+ *
+ * The @prio and @req_prio fields are particularly important to allow
+ * spin-waiting to timeout and give up without the risk of a waiter being
+ * assigned the lock after giving up.
+ */
+struct nbcon_state {
+ union {
+ unsigned int atom;
+ struct {
+ unsigned int prio : 2;
+ unsigned int req_prio : 2;
+ unsigned int unsafe : 1;
+ unsigned int unsafe_takeover : 1;
+ unsigned int cpu : 24;
+ };
+ };
+};
+
+/*
+ * The nbcon_state struct is used to easily create and interpret values that
+ * are stored in the @console::nbcon_state variable. Ensure this struct stays
+ * within the size boundaries of the atomic variable's underlying type in
+ * order to avoid any accidental truncation.
+ */
+static_assert(sizeof(struct nbcon_state) <= sizeof(int));
+
+/**
+ * enum nbcon_prio - console owner priority for nbcon consoles
+ * @NBCON_PRIO_NONE: Unused
+ * @NBCON_PRIO_NORMAL: Normal (non-emergency) usage
+ * @NBCON_PRIO_EMERGENCY: Emergency output (WARN/OOPS...)
+ * @NBCON_PRIO_PANIC: Panic output
+ * @NBCON_PRIO_MAX: The number of priority levels
*
- * If a console driver is marked CON_BOOT then it will be auto-unregistered
- * when the first real console is registered. This is for early-printk drivers.
+ * A higher priority context can takeover the console when it is
+ * in the safe state. The final attempt to flush consoles in panic()
+ * can be allowed to do so even in an unsafe state (Hope and pray).
+ */
+enum nbcon_prio {
+ NBCON_PRIO_NONE = 0,
+ NBCON_PRIO_NORMAL,
+ NBCON_PRIO_EMERGENCY,
+ NBCON_PRIO_PANIC,
+ NBCON_PRIO_MAX,
+};
+
+struct console;
+struct printk_buffers;
+
+/**
+ * struct nbcon_context - Context for console acquire/release
+ * @console: The associated console
+ * @spinwait_max_us: Limit for spin-wait acquire
+ * @prio: Priority of the context
+ * @allow_unsafe_takeover: Allow performing takeover even if unsafe. Can
+ * be used only with NBCON_PRIO_PANIC @prio. It
+ * might cause a system freeze when the console
+ * is used later.
+ * @backlog: Ringbuffer has pending records
+ * @pbufs: Pointer to the text buffer for this context
+ * @seq: The sequence number to print for this context
*/
+struct nbcon_context {
+ /* members set by caller */
+ struct console *console;
+ unsigned int spinwait_max_us;
+ enum nbcon_prio prio;
+ unsigned int allow_unsafe_takeover : 1;
-#define CON_PRINTBUFFER (1)
-#define CON_CONSDEV (2) /* Preferred console, /dev/console */
-#define CON_ENABLED (4)
-#define CON_BOOT (8)
-#define CON_ANYTIME (16) /* Safe to call when cpu is offline */
-#define CON_BRL (32) /* Used for a braille device */
-#define CON_EXTENDED (64) /* Use the extended output format a la /dev/kmsg */
+ /* members set by emit */
+ unsigned int backlog : 1;
+ /* members set by acquire */
+ struct printk_buffers *pbufs;
+ u64 seq;
+};
+
+/**
+ * struct nbcon_write_context - Context handed to the nbcon write callbacks
+ * @ctxt: The core console context
+ * @outbuf: Pointer to the text buffer for output
+ * @len: Length to write
+ * @unsafe_takeover: If a hostile takeover in an unsafe state has occurred
+ */
+struct nbcon_write_context {
+ struct nbcon_context __private ctxt;
+ char *outbuf;
+ unsigned int len;
+ bool unsafe_takeover;
+};
+
+/**
+ * struct console - The console descriptor structure
+ * @name: The name of the console driver
+ * @write: Legacy write callback to output messages (Optional)
+ * @read: Read callback for console input (Optional)
+ * @device: The underlying TTY device driver (Optional)
+ * @unblank: Callback to unblank the console (Optional)
+ * @setup: Callback for initializing the console (Optional)
+ * @exit: Callback for teardown of the console (Optional)
+ * @match: Callback for matching a console (Optional)
+ * @flags: Console flags. See enum cons_flags
+ * @index: Console index, e.g. port number
+ * @cflag: TTY control mode flags
+ * @ispeed: TTY input speed
+ * @ospeed: TTY output speed
+ * @seq: Sequence number of the next ringbuffer record to print
+ * @dropped: Number of unreported dropped ringbuffer records
+ * @data: Driver private data
+ * @node: hlist node for the console list
+ *
+ * @nbcon_state: State for nbcon consoles
+ * @nbcon_seq: Sequence number of the next record for nbcon to print
+ * @nbcon_device_ctxt: Context available for non-printing operations
+ * @nbcon_prev_seq: Seq num the previous nbcon owner was assigned to print
+ * @pbufs: Pointer to nbcon private buffer
+ * @kthread: Printer kthread for this console
+ * @rcuwait: RCU-safe wait object for @kthread waking
+ * @irq_work: Defer @kthread waking to IRQ work context
+ */
struct console {
- char name[16];
- void (*write)(struct console *, const char *, unsigned);
- int (*read)(struct console *, char *, unsigned);
- struct tty_driver *(*device)(struct console *, int *);
- void (*unblank)(void);
- int (*setup)(struct console *, char *);
- int (*exit)(struct console *);
- int (*match)(struct console *, char *name, int idx, char *options);
- short flags;
- short index;
- int cflag;
- void *data;
- struct console *next;
+ char name[16];
+ void (*write)(struct console *co, const char *s, unsigned int count);
+ int (*read)(struct console *co, char *s, unsigned int count);
+ struct tty_driver *(*device)(struct console *co, int *index);
+ void (*unblank)(void);
+ int (*setup)(struct console *co, char *options);
+ int (*exit)(struct console *co);
+ int (*match)(struct console *co, char *name, int idx, char *options);
+ short flags;
+ short index;
+ int cflag;
+ uint ispeed;
+ uint ospeed;
+ u64 seq;
+ unsigned long dropped;
+ void *data;
+ struct hlist_node node;
+
+ /* nbcon console specific members */
+
+ /**
+ * @write_atomic:
+ *
+ * NBCON callback to write out text in any context. (Optional)
+ *
+ * This callback is called with the console already acquired. However,
+ * a higher priority context is allowed to take it over by default.
+ *
+ * The callback must call nbcon_enter_unsafe() and nbcon_exit_unsafe()
+ * around any code where the takeover is not safe, for example, when
+ * manipulating the serial port registers.
+ *
+ * nbcon_enter_unsafe() will fail if the context has lost the console
+ * ownership in the meantime. In this case, the callback is no longer
+ * allowed to go forward. It must back out immediately and carefully.
+ * The buffer content is also no longer trusted since it no longer
+ * belongs to the context.
+ *
+ * The callback should allow the takeover whenever it is safe. It
+ * increases the chance to see messages when the system is in trouble.
+ * If the driver must reacquire ownership in order to finalize or
+ * revert hardware changes, nbcon_reacquire_nobuf() can be used.
+ * However, on reacquire the buffer content is no longer available. A
+ * reacquire cannot be used to resume printing.
+ *
+ * The callback can be called from any context (including NMI).
+ * Therefore it must avoid usage of any locking and instead rely
+ * on the console ownership for synchronization.
+ */
+ void (*write_atomic)(struct console *con, struct nbcon_write_context *wctxt);
+
+ /**
+ * @write_thread:
+ *
+ * NBCON callback to write out text in task context.
+ *
+ * This callback must be called only in task context with both
+ * device_lock() and the nbcon console acquired with
+ * NBCON_PRIO_NORMAL.
+ *
+ * The same rules for console ownership verification and unsafe
+ * sections handling applies as with write_atomic().
+ *
+ * The console ownership handling is necessary for synchronization
+ * against write_atomic() which is synchronized only via the context.
+ *
+ * The device_lock() provides the primary serialization for operations
+ * on the device. It might be as relaxed (mutex)[*] or as tight
+ * (disabled preemption and interrupts) as needed. It allows
+ * the kthread to operate in the least restrictive mode[**].
+ *
+ * [*] Standalone nbcon_context_try_acquire() is not safe with
+ * the preemption enabled, see nbcon_owner_matches(). But it
+ * can be safe when always called in the preemptive context
+ * under the device_lock().
+ *
+ * [**] The device_lock() makes sure that nbcon_context_try_acquire()
+ * would never need to spin which is important especially with
+ * PREEMPT_RT.
+ */
+ void (*write_thread)(struct console *con, struct nbcon_write_context *wctxt);
+
+ /**
+ * @device_lock:
+ *
+ * NBCON callback to begin synchronization with driver code.
+ *
+ * Console drivers typically must deal with access to the hardware
+ * via user input/output (such as an interactive login shell) and
+ * output of kernel messages via printk() calls. This callback is
+ * called by the printk-subsystem whenever it needs to synchronize
+ * with hardware access by the driver. It should be implemented to
+ * use whatever synchronization mechanism the driver is using for
+ * itself (for example, the port lock for uart serial consoles).
+ *
+ * The callback is always called from task context. It may use any
+ * synchronization method required by the driver.
+ *
+ * IMPORTANT: The callback MUST disable migration. The console driver
+ * may be using a synchronization mechanism that already takes
+ * care of this (such as spinlocks). Otherwise this function must
+ * explicitly call migrate_disable().
+ *
+ * The flags argument is provided as a convenience to the driver. It
+ * will be passed again to device_unlock(). It can be ignored if the
+ * driver does not need it.
+ */
+ void (*device_lock)(struct console *con, unsigned long *flags);
+
+ /**
+ * @device_unlock:
+ *
+ * NBCON callback to finish synchronization with driver code.
+ *
+ * It is the counterpart to device_lock().
+ *
+ * This callback is always called from task context. It must
+ * appropriately re-enable migration (depending on how device_lock()
+ * disabled migration).
+ *
+ * The flags argument is the value of the same variable that was
+ * passed to device_lock().
+ */
+ void (*device_unlock)(struct console *con, unsigned long flags);
+
+ atomic_t __private nbcon_state;
+ atomic_long_t __private nbcon_seq;
+ struct nbcon_context __private nbcon_device_ctxt;
+ atomic_long_t __private nbcon_prev_seq;
+
+ struct printk_buffers *pbufs;
+ struct task_struct *kthread;
+ struct rcuwait rcuwait;
+ struct irq_work irq_work;
};
+#ifdef CONFIG_LOCKDEP
+extern void lockdep_assert_console_list_lock_held(void);
+#else
+static inline void lockdep_assert_console_list_lock_held(void)
+{
+}
+#endif
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+extern bool console_srcu_read_lock_is_held(void);
+#else
+static inline bool console_srcu_read_lock_is_held(void)
+{
+ return 1;
+}
+#endif
+
+extern int console_srcu_read_lock(void);
+extern void console_srcu_read_unlock(int cookie);
+
+extern void console_list_lock(void) __acquires(console_mutex);
+extern void console_list_unlock(void) __releases(console_mutex);
+
+extern struct hlist_head console_list;
+
+/**
+ * console_srcu_read_flags - Locklessly read flags of a possibly registered
+ * console
+ * @con: struct console pointer of console to read flags from
+ *
+ * Locklessly reading @con->flags provides a consistent read value because
+ * there is at most one CPU modifying @con->flags and that CPU is using only
+ * read-modify-write operations to do so.
+ *
+ * Requires console_srcu_read_lock to be held, which implies that @con might
+ * be a registered console. The purpose of holding console_srcu_read_lock is
+ * to guarantee that the console state is valid (CON_SUSPENDED/CON_ENABLED)
+ * and that no exit/cleanup routines will run if the console is currently
+ * undergoing unregistration.
+ *
+ * If the caller is holding the console_list_lock or it is _certain_ that
+ * @con is not and will not become registered, the caller may read
+ * @con->flags directly instead.
+ *
+ * Context: Any context.
+ * Return: The current value of the @con->flags field.
+ */
+static inline short console_srcu_read_flags(const struct console *con)
+{
+ WARN_ON_ONCE(!console_srcu_read_lock_is_held());
+
+ /*
+ * The READ_ONCE() matches the WRITE_ONCE() when @flags are modified
+ * for registered consoles with console_srcu_write_flags().
+ */
+ return data_race(READ_ONCE(con->flags));
+}
+
+/**
+ * console_srcu_write_flags - Write flags for a registered console
+ * @con: struct console pointer of console to write flags to
+ * @flags: new flags value to write
+ *
+ * Only use this function to write flags for registered consoles. It
+ * requires holding the console_list_lock.
+ *
+ * Context: Any context.
+ */
+static inline void console_srcu_write_flags(struct console *con, short flags)
+{
+ lockdep_assert_console_list_lock_held();
+
+ /* This matches the READ_ONCE() in console_srcu_read_flags(). */
+ WRITE_ONCE(con->flags, flags);
+}
+
+/* Variant of console_is_registered() when the console_list_lock is held. */
+static inline bool console_is_registered_locked(const struct console *con)
+{
+ lockdep_assert_console_list_lock_held();
+ return !hlist_unhashed(&con->node);
+}
+
/*
- * for_each_console() allows you to iterate on each console
+ * console_is_registered - Check if the console is registered
+ * @con: struct console pointer of console to check
+ *
+ * Context: Process context. May sleep while acquiring console list lock.
+ * Return: true if the console is in the console list, otherwise false.
+ *
+ * If false is returned for a console that was previously registered, it
+ * can be assumed that the console's unregistration is fully completed,
+ * including the exit() callback after console list removal.
*/
-#define for_each_console(con) \
- for (con = console_drivers; con != NULL; con = con->next)
+static inline bool console_is_registered(const struct console *con)
+{
+ bool ret;
+
+ console_list_lock();
+ ret = console_is_registered_locked(con);
+ console_list_unlock();
+ return ret;
+}
+
+/**
+ * for_each_console_srcu() - Iterator over registered consoles
+ * @con: struct console pointer used as loop cursor
+ *
+ * Although SRCU guarantees the console list will be consistent, the
+ * struct console fields may be updated by other CPUs while iterating.
+ *
+ * Requires console_srcu_read_lock to be held. Can be invoked from
+ * any context.
+ */
+#define for_each_console_srcu(con) \
+ hlist_for_each_entry_srcu(con, &console_list, node, \
+ console_srcu_read_lock_is_held())
+
+/**
+ * for_each_console() - Iterator over registered consoles
+ * @con: struct console pointer used as loop cursor
+ *
+ * The console list and the &console.flags are immutable while iterating.
+ *
+ * Requires console_list_lock to be held.
+ */
+#define for_each_console(con) \
+ lockdep_assert_console_list_lock_held(); \
+ hlist_for_each_entry(con, &console_list, node)
+
+#ifdef CONFIG_PRINTK
+extern void nbcon_cpu_emergency_enter(void);
+extern void nbcon_cpu_emergency_exit(void);
+extern bool nbcon_can_proceed(struct nbcon_write_context *wctxt);
+extern bool nbcon_enter_unsafe(struct nbcon_write_context *wctxt);
+extern bool nbcon_exit_unsafe(struct nbcon_write_context *wctxt);
+extern void nbcon_reacquire_nobuf(struct nbcon_write_context *wctxt);
+#else
+static inline void nbcon_cpu_emergency_enter(void) { }
+static inline void nbcon_cpu_emergency_exit(void) { }
+static inline bool nbcon_can_proceed(struct nbcon_write_context *wctxt) { return false; }
+static inline bool nbcon_enter_unsafe(struct nbcon_write_context *wctxt) { return false; }
+static inline bool nbcon_exit_unsafe(struct nbcon_write_context *wctxt) { return false; }
+static inline void nbcon_reacquire_nobuf(struct nbcon_write_context *wctxt) { }
+#endif
extern int console_set_on_cmdline;
extern struct console *early_console;
@@ -168,10 +622,10 @@ enum con_flush_mode {
CONSOLE_REPLAY_ALL,
};
-extern int add_preferred_console(char *name, int idx, char *options);
+extern int add_preferred_console(const char *name, const short idx, char *options);
+extern void console_force_preferred_locked(struct console *con);
extern void register_console(struct console *);
extern int unregister_console(struct console *);
-extern struct console *console_drivers;
extern void console_lock(void);
extern int console_trylock(void);
extern void console_unlock(void);
@@ -179,8 +633,8 @@ extern void console_conditional_schedule(void);
extern void console_unblank(void);
extern void console_flush_on_panic(enum con_flush_mode mode);
extern struct tty_driver *console_device(int *);
-extern void console_stop(struct console *);
-extern void console_start(struct console *);
+extern void console_suspend(struct console *);
+extern void console_resume(struct console *);
extern int is_console_locked(void);
extern int braille_register_console(struct console *, int index,
char *console_options, char *braille_options);
@@ -194,8 +648,8 @@ static inline void console_sysfs_notify(void)
extern bool console_suspend_enabled;
/* Suspend and resume console messages over PM events */
-extern void suspend_console(void);
-extern void resume_console(void);
+extern void console_suspend_all(void);
+extern void console_resume_all(void);
int mda_console_init(void);
@@ -212,18 +666,6 @@ void vcs_remove_sysfs(int index);
*/
extern atomic_t ignore_console_lock_warning;
-/* VESA Blanking Levels */
-#define VESA_NO_BLANKING 0
-#define VESA_VSYNC_SUSPEND 1
-#define VESA_HSYNC_SUSPEND 2
-#define VESA_POWERDOWN 3
-
-#ifdef CONFIG_VGA_CONSOLE
-extern bool vgacon_text_force(void);
-#else
-static inline bool vgacon_text_force(void) { return false; }
-#endif
-
extern void console_init(void);
/* For deferred console takeover */