b2f9b77c7f
When in time-travel mode (infinite-cpu or external) time should not pass for writing to the console. As such, it makes sense to put the FD for the output side into blocking mode and simply let any write to it hang. If we did not do this, then time could pass waiting for the console to become writable again. This is not desirable as it has random effects on the clock between runs. Implement this by duplicating the FD if output is active in a relevant mode and setting the duplicate to be blocking. This avoids changing the input channel to be blocking should it exists. After this, use the blocking FD for all write operations and do not allocate an IRQ it is set. Without time-travel mode fd_out will always match fd_in and IRQs are registered. Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Link: https://patch.msgid.link/20231018123643.1255813-4-benjamin@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
50 lines
1.5 KiB
C
50 lines
1.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2000, 2001 Jeff Dike (jdike@karaya.com)
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*/
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#ifndef __CHAN_KERN_H__
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#define __CHAN_KERN_H__
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#include <linux/tty.h>
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#include <linux/list.h>
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#include <linux/console.h>
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#include "chan_user.h"
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#include "line.h"
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struct chan {
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struct list_head list;
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struct list_head free_list;
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struct line *line;
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char *dev;
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unsigned int primary:1;
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unsigned int input:1;
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unsigned int output:1;
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unsigned int opened:1;
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unsigned int enabled:1;
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int fd_in;
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int fd_out; /* only different to fd_in if blocking output is needed */
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const struct chan_ops *ops;
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void *data;
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};
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extern void chan_interrupt(struct line *line, int irq);
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extern int parse_chan_pair(char *str, struct line *line, int device,
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const struct chan_opts *opts, char **error_out);
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extern int write_chan(struct chan *chan, const u8 *buf, size_t len,
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int write_irq);
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extern int console_write_chan(struct chan *chan, const char *buf,
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int len);
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extern int console_open_chan(struct line *line, struct console *co);
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extern void deactivate_chan(struct chan *chan, int irq);
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extern void chan_enable_winch(struct chan *chan, struct tty_port *port);
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extern int enable_chan(struct line *line);
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extern void close_chan(struct line *line);
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extern int chan_window_size(struct line *line,
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unsigned short *rows_out,
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unsigned short *cols_out);
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extern int chan_config_string(struct line *line, char *str, int size,
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char **error_out);
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#endif
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