From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934956AbcKPUbg (ORCPT ); Wed, 16 Nov 2016 15:31:36 -0500 Received: from mout.gmx.net ([212.227.17.22]:53305 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932201AbcKPUbc (ORCPT ); Wed, 16 Nov 2016 15:31:32 -0500 From: =?UTF-8?q?Manuel=20Sch=C3=B6lling?= To: plagnioj@jcrosoft.com, tomi.valkeinen@ti.com Cc: manuel.schoelling@gmx.de, jslaby@suse.cz, gregkh@linuxfoundation.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, andrey_utkin@fastmail.com Subject: [PATCH v4.1 2/2] console: Add persistent scrollback buffers for all VGA consoles Date: Wed, 16 Nov 2016 21:31:00 +0100 Message-Id: <1479328260-16286-3-git-send-email-manuel.schoelling@gmx.de> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1479328260-16286-1-git-send-email-manuel.schoelling@gmx.de> References: <1479317933-21849-1-git-send-email-manuel.schoelling@gmx.de> <1479328260-16286-1-git-send-email-manuel.schoelling@gmx.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Provags-ID: V03:K0:IprgI1MPAx3hnKM5bWRu+1cg4xSm4V0hZy/eYCKnWbItyFUWkWd lzEEvZFFr7c89Wga7z7aJOwxVR/a2fWHzx/n0esMizQzyQRvYx19R3Luc0YU5GhoZotMf47 o7iVG5i9XAkhXYUUqpR+JqrfWO4FigKzvduUYcbfU6yeIfpEVh7DYJr23Waq5Pra6AIqBcW a4ljKNPdmnQfsXAqbQ86Q== X-UI-Out-Filterresults: notjunk:1;V01:K0:eu3laWdiLaU=:w6azbakS3A+irzx6kiVUEq XVaVGdpvcpEG/OBa2zVlMH7s8rlvMfE4fImHvLPbNdLwGCVlGBYhGDyZmOXnySQwtRiwMo6Uw 2vxbYba8kY1Yii4GaAsLOH9ARrp958EduvlNGQGHUi6+uQaowayZ0Q+N2vMbdbFqLd2LKWZ3I Xy1ydV8VcPhP5XDT6eo6yGKyyG1RBP6n/1VnmfqjG7WooZxu7Dy0jtRzzpJc4tBOsbZkrKH71 vLYFnkLxL7BALl10SKx4s+HyGQb5RC7DBLZbVp76PUddn3jGl5+XSEylwHz+PY40eOLHG1sUc f5MWzC3ka5nZqEaI1aA7mZS8Iudxd+hZfQeqSzpsO9BpF5RyY1KGCyqYrkvAMeoasvOQ8wdAV M4V0wn5n7mKMIPouWLy3ru8rZ7au2v1uBetlBKlBUSiH6ok45RE0Z/9qMqjq2nXI7rslzj9Nt Cq0U14YmBpaBPk5DJmw//2I2YHi4aJpgij6LQyLUOBH2O+xt2EyfXUQ4nPthCm+vWlB92NlxZ J6IJSiBRB3vxy9A0j93JlycqjLRH//oFbtk8COpho/px6oXXpLauGL9Noly+k6xDP4Xm8T0qu a7pMfpSzNB0JxKCV92rqwvm6VUiKX5V168Ia24e2fhhRX3E8Zxt1HZQNMCspQ7FG69wj7DeMU uEomxE+T4e4vSoh1OAlnYVecne4a+G+oZW5v/s4wLu8tlS6wte18GkUaQXW6IuzpaK173iazo KbqqHLw/YVxlTiMqN4PAvm39DS5JseMPnqB03eoJNbl14xzNb2dr8HSsbzCRM5viUAk8fmCLg XOnvt5j Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add a scrollback buffers for each VGA console. The benefit is that the scrollback history is not flushed when switching between consoles but is persistent. The buffers are allocated on demand when a new console is opened. This breaks tools like clear_console that rely on flushing the scrollback history by switching back and forth between consoles which is why this feature is disabled by default. Use the escape sequence \e[3J instead for flushing the buffer. Signed-off-by: Manuel Schölling --- drivers/video/console/Kconfig | 23 ++++++- drivers/video/console/vgacon.c | 134 +++++++++++++++++++++++++++++------------ 2 files changed, 114 insertions(+), 43 deletions(-) diff --git a/drivers/video/console/Kconfig b/drivers/video/console/Kconfig index 38da6e2..8167540 100644 --- a/drivers/video/console/Kconfig +++ b/drivers/video/console/Kconfig @@ -43,9 +43,26 @@ config VGACON_SOFT_SCROLLBACK_SIZE range 1 1024 default "64" help - Enter the amount of System RAM to allocate for the scrollback - buffer. Each 64KB will give you approximately 16 80x25 - screenfuls of scrollback buffer + Enter the amount of System RAM to allocate for scrollback + buffers of VGA consoles. Each 64KB will give you approximately + 16 80x25 screenfuls of scrollback buffer. + +config VGACON_SOFT_SCROLLBACK_PERSISTENT + bool "Persistent Scrollback History for each console" + depends on VGACON_SOFT_SCROLLBACK + default n + help + Say Y here if the scrollback history should persist when switching + between consoles. Otherwise, the scrollback history will be flushed + each time the console is switched. + + This breaks legacy versions of tools like clear_console which + might cause security issues. + Use the escape sequence \e[3J instead if this feature is activated. + + Note that a buffer of VGACON_SOFT_SCROLLBACK_SIZE is taken for each + created tty device. + So if you use a RAM-constrained system, say N here. config MDA_CONSOLE depends on !M68K && !PARISC && ISA diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c index 1fee18f..8314f69 100644 --- a/drivers/video/console/vgacon.c +++ b/drivers/video/console/vgacon.c @@ -162,7 +162,7 @@ static inline void vga_set_mem_top(struct vc_data *c) #ifdef CONFIG_VGACON_SOFT_SCROLLBACK /* software scrollback */ -static struct vgacon_scrollback_info { +struct vgacon_scrollback_info { void *data; int tail; int size; @@ -171,63 +171,116 @@ static struct vgacon_scrollback_info { int cur; int save; int restore; -} vgacon_scrollback; +}; +static struct vgacon_scrollback_info *vgacon_scrollback_cur; +#ifdef CONFIG_VGACON_SOFT_SCROLLBACK_PERSISTENT +static struct vgacon_scrollback_info vgacon_scrollbacks[MAX_NR_CONSOLES]; +#else +static struct vgacon_scrollback_info vgacon_scrollbacks[1]; +#endif + +static void vgacon_scrollback_reset(size_t reset_size) +{ + if (vgacon_scrollback_cur->data && reset_size > 0) + memset(vgacon_scrollback_cur->data, 0, reset_size); + + vgacon_scrollback_cur->cnt = 0; + vgacon_scrollback_cur->tail = 0; + vgacon_scrollback_cur->cur = 0; +} + +static void vgacon_scrollback_init(int vc_num) +{ + int pitch = vga_video_num_columns * 2; + size_t size = CONFIG_VGACON_SOFT_SCROLLBACK_SIZE * 1024; + int rows = size/pitch; + void *data; + + data = kcalloc(CONFIG_VGACON_SOFT_SCROLLBACK_SIZE, 1024, GFP_NOWAIT); + if (data) { + vgacon_scrollbacks[vc_num].data = data; + vgacon_scrollback_cur = &vgacon_scrollbacks[vc_num]; + + vgacon_scrollback_cur->rows = rows - 1; + vgacon_scrollback_cur->size = rows * pitch; -static void vgacon_scrollback_init(int pitch) + vgacon_scrollback_reset(0); + } else { + pr_warn("VGAcon: failed to allocate memory for scrollback. Trying to reuse previous buffer.\n"); + /* Leave vgacon_scrollback_cur untouched but reset its content */ + vgacon_scrollback_reset(size); + } +} + +static void vgacon_switch_scrollback(int vc_num) { - int rows = CONFIG_VGACON_SOFT_SCROLLBACK_SIZE * 1024/pitch; - - if (vgacon_scrollback.data) { - vgacon_scrollback.cnt = 0; - vgacon_scrollback.tail = 0; - vgacon_scrollback.cur = 0; - vgacon_scrollback.rows = rows - 1; - vgacon_scrollback.size = rows * pitch; +#ifdef CONFIG_VGACON_SOFT_SCROLLBACK_PERSISTENT + if (!vgacon_scrollbacks[vc_num].data) + vgacon_scrollback_init(vc_num); + else + vgacon_scrollback_cur = &vgacon_scrollbacks[vc_num]; +#else + vc_num = 0; + + if (!vgacon_scrollbacks[vc_num].data) + vgacon_scrollback_init(vc_num); + else { + size_t size = CONFIG_VGACON_SOFT_SCROLLBACK_SIZE * 1024; + + vgacon_scrollback_reset(size); } +#endif } static void vgacon_scrollback_startup(void) { - vgacon_scrollback.data = kcalloc(CONFIG_VGACON_SOFT_SCROLLBACK_SIZE, 1024, GFP_NOWAIT); - vgacon_scrollback_init(vga_video_num_columns * 2); + int i; + + for (i = 0; i < ARRAY_SIZE(vgacon_scrollbacks); ++i) + vgacon_scrollbacks[i].data = NULL; + + vgacon_scrollback_cur = &vgacon_scrollbacks[0]; + vgacon_scrollback_init(0); } static void vgacon_scrollback_update(struct vc_data *c, int t, int count) { void *p; - if (!vgacon_scrollback.size || c->vc_num != fg_console) + if (!vgacon_scrollback_cur->data || !vgacon_scrollback_cur->size) return; p = (void *) (c->vc_origin + t * c->vc_size_row); while (count--) { - scr_memcpyw(vgacon_scrollback.data + vgacon_scrollback.tail, + scr_memcpyw(vgacon_scrollback_cur->data + + vgacon_scrollback_cur->tail, p, c->vc_size_row); - vgacon_scrollback.cnt++; + + vgacon_scrollback_cur->cnt++; p += c->vc_size_row; - vgacon_scrollback.tail += c->vc_size_row; + vgacon_scrollback_cur->tail += c->vc_size_row; - if (vgacon_scrollback.tail >= vgacon_scrollback.size) - vgacon_scrollback.tail = 0; + if (vgacon_scrollback_cur->tail >= vgacon_scrollback_cur->size) + vgacon_scrollback_cur->tail = 0; - if (vgacon_scrollback.cnt > vgacon_scrollback.rows) - vgacon_scrollback.cnt = vgacon_scrollback.rows; + if (vgacon_scrollback_cur->cnt > vgacon_scrollback_cur->rows) + vgacon_scrollback_cur->cnt = vgacon_scrollback_cur->rows; - vgacon_scrollback.cur = vgacon_scrollback.cnt; + vgacon_scrollback_cur->cur = vgacon_scrollback_cur->cnt; } } static void vgacon_restore_screen(struct vc_data *c) { - vgacon_scrollback.save = 0; + vgacon_scrollback_cur->save = 0; - if (!vga_is_gfx && !vgacon_scrollback.restore) { + if (!vga_is_gfx && !vgacon_scrollback_cur->restore) { scr_memcpyw((u16 *) c->vc_origin, (u16 *) c->vc_screenbuf, c->vc_screenbuf_size > vga_vram_size ? vga_vram_size : c->vc_screenbuf_size); - vgacon_scrollback.restore = 1; - vgacon_scrollback.cur = vgacon_scrollback.cnt; + vgacon_scrollback_cur->restore = 1; + vgacon_scrollback_cur->cur = vgacon_scrollback_cur->cnt; } } @@ -241,17 +294,17 @@ static void vgacon_scrolldelta(struct vc_data *c, int lines) return; } - if (!vgacon_scrollback.data) + if (!vgacon_scrollback_cur->data) return; - if (!vgacon_scrollback.save) { + if (!vgacon_scrollback_cur->save) { vgacon_cursor(c, CM_ERASE); vgacon_save_screen(c); - vgacon_scrollback.save = 1; + vgacon_scrollback_cur->save = 1; } - vgacon_scrollback.restore = 0; - start = vgacon_scrollback.cur + lines; + vgacon_scrollback_cur->restore = 0; + start = vgacon_scrollback_cur->cur + lines; end = start + abs(lines); if (start < 0) @@ -266,16 +319,16 @@ static void vgacon_scrolldelta(struct vc_data *c, int lines) if (end > vgacon_scrollback.cnt) end = vgacon_scrollback.cnt; - vgacon_scrollback.cur = start; + vgacon_scrollback_cur->cur = start; count = end - start; - soff = vgacon_scrollback.tail - ((vgacon_scrollback.cnt - end) * - c->vc_size_row); + soff = vgacon_scrollback_cur->tail - (c->vc_size_row * + (vgacon_scrollback_cur->cnt - end)); soff -= count * c->vc_size_row; if (soff < 0) - soff += vgacon_scrollback.size; + soff += vgacon_scrollback_cur->size; - count = vgacon_scrollback.cnt - start; + count = vgacon_scrollback_cur->cnt - start; if (count > c->vc_rows) count = c->vc_rows; @@ -289,13 +342,13 @@ static void vgacon_scrolldelta(struct vc_data *c, int lines) count *= c->vc_size_row; /* how much memory to end of buffer left? */ - copysize = min(count, vgacon_scrollback.size - soff); - scr_memcpyw(d, vgacon_scrollback.data + soff, copysize); + copysize = min(count, vgacon_scrollback_cur->size - soff); + scr_memcpyw(d, vgacon_scrollback_cur->data + soff, copysize); d += copysize; count -= copysize; if (count) { - scr_memcpyw(d, vgacon_scrollback.data, count); + scr_memcpyw(d, vgacon_scrollback_cur->data, count); d += count; } @@ -308,6 +361,7 @@ static void vgacon_scrolldelta(struct vc_data *c, int lines) #define vgacon_scrollback_startup(...) do { } while (0) #define vgacon_scrollback_init(...) do { } while (0) #define vgacon_scrollback_update(...) do { } while (0) +#define vgacon_switch_scrollback(...) do { } while (0) static void vgacon_restore_screen(struct vc_data *c) { @@ -782,7 +836,7 @@ static int vgacon_switch(struct vc_data *c) vgacon_doresize(c, c->vc_cols, c->vc_rows); } - vgacon_scrollback_init(c->vc_size_row); + vgacon_switch_scrollback(c->vc_num); return 0; /* Redrawing not needed */ } -- 2.1.4