397 lines
13 KiB
C
397 lines
13 KiB
C
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/*
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* linux/include/linux/console.h
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*
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* Copyright (C) 1993 Hamish Macdonald
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file COPYING in the main directory of this archive
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* for more details.
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*
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* Changed:
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* 10-Mar-94: Arno Griffioen: Conversion for vt100 emulator port from PC LINUX
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*/
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#ifndef _LINUX_CONSOLE_H_
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#define _LINUX_CONSOLE_H_ 1
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#include <linux/atomic.h>
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#include <linux/bits.h>
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#include <linux/rculist.h>
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#include <linux/types.h>
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struct vc_data;
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struct console_font_op;
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struct console_font;
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struct module;
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struct tty_struct;
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struct notifier_block;
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enum con_scroll {
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SM_UP,
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SM_DOWN,
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};
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enum vc_intensity;
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/**
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* struct consw - callbacks for consoles
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*
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* @con_scroll: move lines from @top to @bottom in direction @dir by @lines.
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* Return true if no generic handling should be done.
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* Invoked by csi_M and printing to the console.
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* @con_set_palette: sets the palette of the console to @table (optional)
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* @con_scrolldelta: the contents of the console should be scrolled by @lines.
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* Invoked by user. (optional)
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*/
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struct consw {
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struct module *owner;
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const char *(*con_startup)(void);
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void (*con_init)(struct vc_data *vc, int init);
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void (*con_deinit)(struct vc_data *vc);
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void (*con_clear)(struct vc_data *vc, int sy, int sx, int height,
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int width);
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void (*con_putc)(struct vc_data *vc, int c, int ypos, int xpos);
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void (*con_putcs)(struct vc_data *vc, const unsigned short *s,
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int count, int ypos, int xpos);
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void (*con_cursor)(struct vc_data *vc, int mode);
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bool (*con_scroll)(struct vc_data *vc, unsigned int top,
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unsigned int bottom, enum con_scroll dir,
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unsigned int lines);
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int (*con_switch)(struct vc_data *vc);
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int (*con_blank)(struct vc_data *vc, int blank, int mode_switch);
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int (*con_font_set)(struct vc_data *vc, struct console_font *font,
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unsigned int vpitch, unsigned int flags);
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int (*con_font_get)(struct vc_data *vc, struct console_font *font,
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unsigned int vpitch);
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int (*con_font_default)(struct vc_data *vc,
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struct console_font *font, char *name);
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int (*con_resize)(struct vc_data *vc, unsigned int width,
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unsigned int height, unsigned int user);
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void (*con_set_palette)(struct vc_data *vc,
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const unsigned char *table);
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void (*con_scrolldelta)(struct vc_data *vc, int lines);
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int (*con_set_origin)(struct vc_data *vc);
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void (*con_save_screen)(struct vc_data *vc);
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u8 (*con_build_attr)(struct vc_data *vc, u8 color,
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enum vc_intensity intensity,
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bool blink, bool underline, bool reverse, bool italic);
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void (*con_invert_region)(struct vc_data *vc, u16 *p, int count);
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u16 *(*con_screen_pos)(const struct vc_data *vc, int offset);
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unsigned long (*con_getxy)(struct vc_data *vc, unsigned long position,
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int *px, int *py);
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/*
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* Flush the video console driver's scrollback buffer
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*/
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void (*con_flush_scrollback)(struct vc_data *vc);
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/*
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* Prepare the console for the debugger. This includes, but is not
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* limited to, unblanking the console, loading an appropriate
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* palette, and allowing debugger generated output.
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*/
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int (*con_debug_enter)(struct vc_data *vc);
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/*
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* Restore the console to its pre-debug state as closely as possible.
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*/
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int (*con_debug_leave)(struct vc_data *vc);
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};
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extern const struct consw *conswitchp;
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extern const struct consw dummy_con; /* dummy console buffer */
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extern const struct consw vga_con; /* VGA text console */
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extern const struct consw newport_con; /* SGI Newport console */
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int con_is_bound(const struct consw *csw);
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int do_unregister_con_driver(const struct consw *csw);
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int do_take_over_console(const struct consw *sw, int first, int last, int deflt);
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void give_up_console(const struct consw *sw);
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#ifdef CONFIG_HW_CONSOLE
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int con_debug_enter(struct vc_data *vc);
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int con_debug_leave(void);
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#else
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static inline int con_debug_enter(struct vc_data *vc)
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{
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return 0;
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}
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static inline int con_debug_leave(void)
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{
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return 0;
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}
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#endif
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/* cursor */
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#define CM_DRAW (1)
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#define CM_ERASE (2)
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#define CM_MOVE (3)
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/*
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* The interface for a console, or any other device that wants to capture
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* console messages (printer driver?)
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*/
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/**
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* cons_flags - General console flags
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* @CON_PRINTBUFFER: Used by newly registered consoles to avoid duplicate
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* output of messages that were already shown by boot
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* consoles or read by userspace via syslog() syscall.
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* @CON_CONSDEV: Indicates that the console driver is backing
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* /dev/console.
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* @CON_ENABLED: Indicates if a console is allowed to print records. If
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* false, the console also will not advance to later
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* records.
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* @CON_BOOT: Marks the console driver as early console driver which
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* is used during boot before the real driver becomes
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* available. It will be automatically unregistered
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* when the real console driver is registered unless
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* "keep_bootcon" parameter is used.
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* @CON_ANYTIME: A misnomed historical flag which tells the core code
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* that the legacy @console::write callback can be invoked
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* on a CPU which is marked OFFLINE. That is misleading as
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* it suggests that there is no contextual limit for
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* invoking the callback. The original motivation was
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* readiness of the per-CPU areas.
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* @CON_BRL: Indicates a braille device which is exempt from
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* receiving the printk spam for obvious reasons.
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* @CON_EXTENDED: The console supports the extended output format of
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* /dev/kmesg which requires a larger output buffer.
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*/
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enum cons_flags {
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CON_PRINTBUFFER = BIT(0),
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CON_CONSDEV = BIT(1),
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CON_ENABLED = BIT(2),
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CON_BOOT = BIT(3),
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CON_ANYTIME = BIT(4),
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CON_BRL = BIT(5),
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CON_EXTENDED = BIT(6),
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};
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/**
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* struct console - The console descriptor structure
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* @name: The name of the console driver
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* @write: Write callback to output messages (Optional)
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* @read: Read callback for console input (Optional)
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* @device: The underlying TTY device driver (Optional)
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* @unblank: Callback to unblank the console (Optional)
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* @setup: Callback for initializing the console (Optional)
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* @exit: Callback for teardown of the console (Optional)
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* @match: Callback for matching a console (Optional)
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* @flags: Console flags. See enum cons_flags
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* @index: Console index, e.g. port number
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* @cflag: TTY control mode flags
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* @ispeed: TTY input speed
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* @ospeed: TTY output speed
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* @seq: Sequence number of the next ringbuffer record to print
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* @dropped: Number of unreported dropped ringbuffer records
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* @data: Driver private data
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* @node: hlist node for the console list
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*/
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struct console {
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char name[16];
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void (*write)(struct console *co, const char *s, unsigned int count);
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int (*read)(struct console *co, char *s, unsigned int count);
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struct tty_driver *(*device)(struct console *co, int *index);
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void (*unblank)(void);
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int (*setup)(struct console *co, char *options);
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int (*exit)(struct console *co);
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int (*match)(struct console *co, char *name, int idx, char *options);
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short flags;
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short index;
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int cflag;
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uint ispeed;
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uint ospeed;
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u64 seq;
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unsigned long dropped;
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void *data;
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struct hlist_node node;
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};
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#ifdef CONFIG_LOCKDEP
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extern void lockdep_assert_console_list_lock_held(void);
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#else
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static inline void lockdep_assert_console_list_lock_held(void)
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{
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}
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#endif
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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extern bool console_srcu_read_lock_is_held(void);
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#else
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static inline bool console_srcu_read_lock_is_held(void)
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{
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return 1;
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}
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#endif
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extern int console_srcu_read_lock(void);
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extern void console_srcu_read_unlock(int cookie);
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extern void console_list_lock(void) __acquires(console_mutex);
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extern void console_list_unlock(void) __releases(console_mutex);
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extern struct hlist_head console_list;
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/**
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* console_srcu_read_flags - Locklessly read the console flags
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* @con: struct console pointer of console to read flags from
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*
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* This function provides the necessary READ_ONCE() and data_race()
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* notation for locklessly reading the console flags. The READ_ONCE()
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* in this function matches the WRITE_ONCE() when @flags are modified
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* for registered consoles with console_srcu_write_flags().
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*
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* Only use this function to read console flags when locklessly
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* iterating the console list via srcu.
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*
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* Context: Any context.
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*/
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static inline short console_srcu_read_flags(const struct console *con)
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{
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WARN_ON_ONCE(!console_srcu_read_lock_is_held());
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/*
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* Locklessly reading console->flags provides a consistent
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* read value because there is at most one CPU modifying
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* console->flags and that CPU is using only read-modify-write
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* operations to do so.
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*/
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return data_race(READ_ONCE(con->flags));
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}
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/**
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* console_srcu_write_flags - Write flags for a registered console
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* @con: struct console pointer of console to write flags to
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* @flags: new flags value to write
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*
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* Only use this function to write flags for registered consoles. It
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* requires holding the console_list_lock.
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*
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* Context: Any context.
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*/
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static inline void console_srcu_write_flags(struct console *con, short flags)
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{
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lockdep_assert_console_list_lock_held();
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/* This matches the READ_ONCE() in console_srcu_read_flags(). */
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WRITE_ONCE(con->flags, flags);
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}
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/* Variant of console_is_registered() when the console_list_lock is held. */
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static inline bool console_is_registered_locked(const struct console *con)
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{
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lockdep_assert_console_list_lock_held();
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return !hlist_unhashed(&con->node);
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}
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/*
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* console_is_registered - Check if the console is registered
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* @con: struct console pointer of console to check
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*
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* Context: Process context. May sleep while acquiring console list lock.
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* Return: true if the console is in the console list, otherwise false.
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*
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* If false is returned for a console that was previously registered, it
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* can be assumed that the console's unregistration is fully completed,
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* including the exit() callback after console list removal.
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*/
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static inline bool console_is_registered(const struct console *con)
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{
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bool ret;
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console_list_lock();
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ret = console_is_registered_locked(con);
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console_list_unlock();
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return ret;
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}
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/**
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* for_each_console_srcu() - Iterator over registered consoles
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* @con: struct console pointer used as loop cursor
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*
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* Although SRCU guarantees the console list will be consistent, the
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* struct console fields may be updated by other CPUs while iterating.
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*
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* Requires console_srcu_read_lock to be held. Can be invoked from
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* any context.
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*/
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#define for_each_console_srcu(con) \
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hlist_for_each_entry_srcu(con, &console_list, node, \
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console_srcu_read_lock_is_held())
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/**
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* for_each_console() - Iterator over registered consoles
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* @con: struct console pointer used as loop cursor
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*
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* The console list and the console->flags are immutable while iterating.
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*
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* Requires console_list_lock to be held.
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*/
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#define for_each_console(con) \
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lockdep_assert_console_list_lock_held(); \
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hlist_for_each_entry(con, &console_list, node)
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extern int console_set_on_cmdline;
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extern struct console *early_console;
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enum con_flush_mode {
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CONSOLE_FLUSH_PENDING,
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CONSOLE_REPLAY_ALL,
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};
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extern int add_preferred_console(char *name, int idx, char *options);
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extern void console_force_preferred_locked(struct console *con);
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extern void register_console(struct console *);
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extern int unregister_console(struct console *);
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extern void console_lock(void);
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extern int console_trylock(void);
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extern void console_unlock(void);
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extern void console_conditional_schedule(void);
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extern void console_unblank(void);
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extern void console_flush_on_panic(enum con_flush_mode mode);
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extern struct tty_driver *console_device(int *);
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extern void console_stop(struct console *);
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extern void console_start(struct console *);
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extern int is_console_locked(void);
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extern int braille_register_console(struct console *, int index,
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char *console_options, char *braille_options);
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extern int braille_unregister_console(struct console *);
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#ifdef CONFIG_TTY
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extern void console_sysfs_notify(void);
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#else
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static inline void console_sysfs_notify(void)
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||
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|
{ }
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||
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|
#endif
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||
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|
extern bool console_suspend_enabled;
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||
|
|
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||
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|
/* Suspend and resume console messages over PM events */
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||
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|
extern void suspend_console(void);
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||
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|
extern void resume_console(void);
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||
|
|
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||
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|
int mda_console_init(void);
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||
|
|
|
||
|
|
void vcs_make_sysfs(int index);
|
||
|
|
void vcs_remove_sysfs(int index);
|
||
|
|
|
||
|
|
/* Some debug stub to catch some of the obvious races in the VT code */
|
||
|
|
#define WARN_CONSOLE_UNLOCKED() \
|
||
|
|
WARN_ON(!atomic_read(&ignore_console_lock_warning) && \
|
||
|
|
!is_console_locked() && !oops_in_progress)
|
||
|
|
/*
|
||
|
|
* Increment ignore_console_lock_warning if you need to quiet
|
||
|
|
* WARN_CONSOLE_UNLOCKED() for debugging purposes.
|
||
|
|
*/
|
||
|
|
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
|
||
|
|
|
||
|
|
extern void console_init(void);
|
||
|
|
|
||
|
|
/* For deferred console takeover */
|
||
|
|
void dummycon_register_output_notifier(struct notifier_block *nb);
|
||
|
|
void dummycon_unregister_output_notifier(struct notifier_block *nb);
|
||
|
|
|
||
|
|
#endif /* _LINUX_CONSOLE_H */
|