Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2#include <linux/slab.h> /* for kmalloc */
3#include <linux/consolemap.h>
4#include <linux/interrupt.h>
5#include <linux/sched.h>
6#include <linux/device.h> /* for dev_warn */
7#include <linux/selection.h>
8#include <linux/workqueue.h>
9#include <linux/tty.h>
10#include <linux/tty_flip.h>
11#include <linux/atomic.h>
12#include <linux/console.h>
13
14#include "speakup.h"
15
16unsigned short spk_xs, spk_ys, spk_xe, spk_ye; /* our region points */
17struct vc_data *spk_sel_cons;
18
19struct speakup_selection_work {
20 struct work_struct work;
21 struct tiocl_selection sel;
22 struct tty_struct *tty;
23};
24
25void speakup_clear_selection(void)
26{
27 console_lock();
28 clear_selection();
29 console_unlock();
30}
31
32static void __speakup_set_selection(struct work_struct *work)
33{
34 struct speakup_selection_work *ssw =
35 container_of(work, struct speakup_selection_work, work);
36
37 struct tty_struct *tty;
38 struct tiocl_selection sel;
39
40 sel = ssw->sel;
41
42 /* this ensures we copy sel before releasing the lock below */
43 rmb();
44
45 /* release the lock by setting tty of the struct to NULL */
46 tty = xchg(&ssw->tty, NULL);
47
48 if (spk_sel_cons != vc_cons[fg_console].d) {
49 spk_sel_cons = vc_cons[fg_console].d;
50 pr_warn("Selection: mark console not the same as cut\n");
51 goto unref;
52 }
53
54 set_selection_kernel(&sel, tty);
55
56unref:
57 tty_kref_put(tty);
58}
59
60static struct speakup_selection_work speakup_sel_work = {
61 .work = __WORK_INITIALIZER(speakup_sel_work.work,
62 __speakup_set_selection)
63};
64
65int speakup_set_selection(struct tty_struct *tty)
66{
67 /* we get kref here first in order to avoid a subtle race when
68 * cancelling selection work. getting kref first establishes the
69 * invariant that if speakup_sel_work.tty is not NULL when
70 * speakup_cancel_selection() is called, it must be the case that a put
71 * kref is pending.
72 */
73 tty_kref_get(tty);
74 if (cmpxchg(&speakup_sel_work.tty, NULL, tty)) {
75 tty_kref_put(tty);
76 return -EBUSY;
77 }
78 /* now we have the 'lock' by setting tty member of
79 * speakup_selection_work. wmb() ensures that writes to
80 * speakup_sel_work don't happen before cmpxchg() above.
81 */
82 wmb();
83
84 speakup_sel_work.sel.xs = spk_xs + 1;
85 speakup_sel_work.sel.ys = spk_ys + 1;
86 speakup_sel_work.sel.xe = spk_xe + 1;
87 speakup_sel_work.sel.ye = spk_ye + 1;
88 speakup_sel_work.sel.sel_mode = TIOCL_SELCHAR;
89
90 schedule_work_on(WORK_CPU_UNBOUND, &speakup_sel_work.work);
91
92 return 0;
93}
94
95void speakup_cancel_selection(void)
96{
97 struct tty_struct *tty;
98
99 cancel_work_sync(&speakup_sel_work.work);
100 /* setting to null so that if work fails to run and we cancel it,
101 * we can run it again without getting EBUSY forever from there on.
102 * we need to use xchg here to avoid race with speakup_set_selection()
103 */
104 tty = xchg(&speakup_sel_work.tty, NULL);
105 if (tty)
106 tty_kref_put(tty);
107}
108
109static void __speakup_paste_selection(struct work_struct *work)
110{
111 struct speakup_selection_work *ssw =
112 container_of(work, struct speakup_selection_work, work);
113 struct tty_struct *tty = xchg(&ssw->tty, NULL);
114
115 paste_selection(tty);
116 tty_kref_put(tty);
117}
118
119static struct speakup_selection_work speakup_paste_work = {
120 .work = __WORK_INITIALIZER(speakup_paste_work.work,
121 __speakup_paste_selection)
122};
123
124int speakup_paste_selection(struct tty_struct *tty)
125{
126 tty_kref_get(tty);
127 if (cmpxchg(&speakup_paste_work.tty, NULL, tty)) {
128 tty_kref_put(tty);
129 return -EBUSY;
130 }
131
132 schedule_work_on(WORK_CPU_UNBOUND, &speakup_paste_work.work);
133 return 0;
134}
135
136void speakup_cancel_paste(void)
137{
138 struct tty_struct *tty;
139
140 cancel_work_sync(&speakup_paste_work.work);
141 tty = xchg(&speakup_paste_work.tty, NULL);
142 if (tty)
143 tty_kref_put(tty);
144}