142 lines · c
1// SPDX-License-Identifier: GPL-2.02#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 25static void __speakup_set_selection(struct work_struct *work)26{27 struct speakup_selection_work *ssw =28 container_of(work, struct speakup_selection_work, work);29 30 struct tty_struct *tty;31 struct tiocl_selection sel;32 33 sel = ssw->sel;34 35 /* this ensures we copy sel before releasing the lock below */36 rmb();37 38 /* release the lock by setting tty of the struct to NULL */39 tty = xchg(&ssw->tty, NULL);40 41 if (spk_sel_cons != vc_cons[fg_console].d) {42 spk_sel_cons = vc_cons[fg_console].d;43 pr_warn("Selection: mark console not the same as cut\n");44 goto unref;45 }46 47 console_lock();48 clear_selection();49 console_unlock();50 51 set_selection_kernel(&sel, tty);52 53unref:54 tty_kref_put(tty);55}56 57static struct speakup_selection_work speakup_sel_work = {58 .work = __WORK_INITIALIZER(speakup_sel_work.work,59 __speakup_set_selection)60};61 62int speakup_set_selection(struct tty_struct *tty)63{64 /* we get kref here first in order to avoid a subtle race when65 * cancelling selection work. getting kref first establishes the66 * invariant that if speakup_sel_work.tty is not NULL when67 * speakup_cancel_selection() is called, it must be the case that a put68 * kref is pending.69 */70 tty_kref_get(tty);71 if (cmpxchg(&speakup_sel_work.tty, NULL, tty)) {72 tty_kref_put(tty);73 return -EBUSY;74 }75 /* now we have the 'lock' by setting tty member of76 * speakup_selection_work. wmb() ensures that writes to77 * speakup_sel_work don't happen before cmpxchg() above.78 */79 wmb();80 81 speakup_sel_work.sel.xs = spk_xs + 1;82 speakup_sel_work.sel.ys = spk_ys + 1;83 speakup_sel_work.sel.xe = spk_xe + 1;84 speakup_sel_work.sel.ye = spk_ye + 1;85 speakup_sel_work.sel.sel_mode = TIOCL_SELCHAR;86 87 schedule_work_on(WORK_CPU_UNBOUND, &speakup_sel_work.work);88 89 return 0;90}91 92void speakup_cancel_selection(void)93{94 struct tty_struct *tty;95 96 cancel_work_sync(&speakup_sel_work.work);97 /* setting to null so that if work fails to run and we cancel it,98 * we can run it again without getting EBUSY forever from there on.99 * we need to use xchg here to avoid race with speakup_set_selection()100 */101 tty = xchg(&speakup_sel_work.tty, NULL);102 if (tty)103 tty_kref_put(tty);104}105 106static void __speakup_paste_selection(struct work_struct *work)107{108 struct speakup_selection_work *ssw =109 container_of(work, struct speakup_selection_work, work);110 struct tty_struct *tty = xchg(&ssw->tty, NULL);111 112 paste_selection(tty);113 tty_kref_put(tty);114}115 116static struct speakup_selection_work speakup_paste_work = {117 .work = __WORK_INITIALIZER(speakup_paste_work.work,118 __speakup_paste_selection)119};120 121int speakup_paste_selection(struct tty_struct *tty)122{123 tty_kref_get(tty);124 if (cmpxchg(&speakup_paste_work.tty, NULL, tty)) {125 tty_kref_put(tty);126 return -EBUSY;127 }128 129 schedule_work_on(WORK_CPU_UNBOUND, &speakup_paste_work.work);130 return 0;131}132 133void speakup_cancel_paste(void)134{135 struct tty_struct *tty;136 137 cancel_work_sync(&speakup_paste_work.work);138 tty = xchg(&speakup_paste_work.tty, NULL);139 if (tty)140 tty_kref_put(tty);141}142