From dbee4cffa1bfe23263edde1d17cdbef0de3a6ac0 Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Mon, 15 Jun 2020 09:48:38 +0200 Subject: vt: convert vc_tab_stop to bitmap vc_tab_stop is used as a bitmap, but defined as an unsigned int array. Switch it to bitmap and convert all users to the bitmap interface. Note the difference in behavior! We no longer mask the top 24 bits away from x, hence we do not wrap tabs at 256th column. Instead, we silently drop attempts to set a tab behind 256 columns. And we will also seek by '\t' to the rightmost column, when behind that boundary. I do not think the original behavior was desired and that someone relies on that. If this turns out to be the case, we can change the added 'if's back to masks here and there instead... (Or we can increase the limit as fb consoles now have 240 chars here. And they could have more with higher than my resolution, of course.) Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20200615074910.19267-6-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman --- drivers/tty/vt/vt.c | 44 ++++++++++++++++++-------------------------- 1 file changed, 18 insertions(+), 26 deletions(-) (limited to 'drivers/tty/vt') diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c index 4e79cda0c2be..3adb7f409524 100644 --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -2052,6 +2052,8 @@ enum { ESnormal, ESesc, ESsquare, ESgetpars, ESfunckey, /* console_lock is held (except via vc_init()) */ static void reset_terminal(struct vc_data *vc, int do_clear) { + unsigned int i; + vc->vc_top = 0; vc->vc_bottom = vc->vc_rows; vc->vc_state = ESnormal; @@ -2082,14 +2084,9 @@ static void reset_terminal(struct vc_data *vc, int do_clear) default_attr(vc); update_attr(vc); - vc->vc_tab_stop[0] = - vc->vc_tab_stop[1] = - vc->vc_tab_stop[2] = - vc->vc_tab_stop[3] = - vc->vc_tab_stop[4] = - vc->vc_tab_stop[5] = - vc->vc_tab_stop[6] = - vc->vc_tab_stop[7] = 0x01010101; + bitmap_zero(vc->vc_tab_stop, VC_TABSTOPS_COUNT); + for (i = 0; i < VC_TABSTOPS_COUNT; i += 8) + set_bit(i, vc->vc_tab_stop); vc->vc_bell_pitch = DEFAULT_BELL_PITCH; vc->vc_bell_duration = DEFAULT_BELL_DURATION; @@ -2147,11 +2144,13 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c) return; case 9: vc->vc_pos -= (vc->state.x << 1); - while (vc->state.x < vc->vc_cols - 1) { - vc->state.x++; - if (vc->vc_tab_stop[7 & (vc->state.x >> 5)] & (1 << (vc->state.x & 31))) - break; - } + + vc->state.x = find_next_bit(vc->vc_tab_stop, + min(vc->vc_cols - 1, VC_TABSTOPS_COUNT), + vc->state.x + 1); + if (vc->state.x >= VC_TABSTOPS_COUNT) + vc->state.x = vc->vc_cols - 1; + vc->vc_pos += (vc->state.x << 1); notify_write(vc, '\t'); return; @@ -2210,7 +2209,8 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c) lf(vc); return; case 'H': - vc->vc_tab_stop[7 & (vc->state.x >> 5)] |= (1 << (vc->state.x & 31)); + if (vc->state.x < VC_TABSTOPS_COUNT) + set_bit(vc->state.x, vc->vc_tab_stop); return; case 'Z': respond_ID(tty); @@ -2421,18 +2421,10 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c) respond_ID(tty); return; case 'g': - if (!vc->vc_par[0]) - vc->vc_tab_stop[7 & (vc->state.x >> 5)] &= ~(1 << (vc->state.x & 31)); - else if (vc->vc_par[0] == 3) { - vc->vc_tab_stop[0] = - vc->vc_tab_stop[1] = - vc->vc_tab_stop[2] = - vc->vc_tab_stop[3] = - vc->vc_tab_stop[4] = - vc->vc_tab_stop[5] = - vc->vc_tab_stop[6] = - vc->vc_tab_stop[7] = 0; - } + if (!vc->vc_par[0] && vc->state.x < VC_TABSTOPS_COUNT) + set_bit(vc->state.x, vc->vc_tab_stop); + else if (vc->vc_par[0] == 3) + bitmap_zero(vc->vc_tab_stop, VC_TABSTOPS_COUNT); return; case 'm': csi_m(vc); -- cgit v1.2.3