Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751852AbcLDKzC (ORCPT ); Sun, 4 Dec 2016 05:55:02 -0500 Received: from mout.gmx.net ([212.227.17.21]:52960 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750979AbcLDKyc (ORCPT ); Sun, 4 Dec 2016 05:54:32 -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, andrey_utkin@fastmail.com, kilobyte@angband.pl, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v7 3/3] console: Add persistent scrollback buffers for all VGA consoles Date: Sun, 4 Dec 2016 11:53:56 +0100 Message-Id: <1480848836-11330-4-git-send-email-manuel.schoelling@gmx.de> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1480848836-11330-1-git-send-email-manuel.schoelling@gmx.de> References: <1480848836-11330-1-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:sPFC1XRxDxq5rBo0TiO8YVvwO3mdGYwiGJCm+9xSuq0b4HGCNeb kcZenZ03QZQjnAFsyU5mkLR/LO5UwjakhejpPFZRxJeYY2Gt/kMvrj0Di1l7LaqahJGplPX +cF/84jYDj+MldJskIuJE8kxC13mQ7n1cWep59JySpEGKoIfF2q5mrNLL4l1wZ+pVzFRCwF dKluGryMmc+VJeHajom1A== X-UI-Out-Filterresults: notjunk:1;V01:K0:hRgeQwJ1NAQ=:Ur6HtV90vwe02woMI9oUKa /tD2t1B4gp9PRFnXuzCBA8V3tgZcZXMBi46yqnzgL1FQZyVU6PE0XJNpntK9MJ6P7FtMyGOB9 t4DBcXR+Ds1KGOHmdViByX8TvkttL7c7ESKZHbiBjwvqYfQ58uCjSMpBKvMWplGMuOlTCtxL7 SYlUCSh5DSADr4q9kO/X4sT42kr4ECgEvhCggC3r3wOQl3cVD2uTnf2RBxk4O4Z6jUB0rMYo1 p/2U82W1WS5c3u+aMLGbXlJOiEzGDuaAS6J+0Nc74mQo/6/RyhQJ73EJg+CLvKP22DlAXt0Fw xPt0epe0nXuZYx8gAINkEjiHZbyV0X9ONdrv+VWiQMAD7bbYXs8+v7kc5f7nwCeJujG8ttAFu HvAnqEtTqOPZVDoCAUU9BIXep65t4c05cJ/owRfY1ThcqAMXeBZkFiXWwkKTQ7e2LpuoKUTwY FfmEB0x9k3RfTGQtyutDwXOAzWZEMn7+Ld2BpuiedcxZ0VVjURAS6CM2c/QNHBLNYXLYzsMVX W4dm8ukriB0dLBrrPzglOTl4DimNb42s8dIOvikumWqg4X38C/ELDG4653Y+XsrsajdxBW6dY UlXa1Hs+56B0nCLjQx2kEWATPCyX73H5PBaR5t4MB/2Tkq1LuelclJV5y10Q2d5S0aBguUiYS 1nuQbFQ/21QrOC1puC5gbwltcXQ4rRoizq/DM/NQN3qGnzJzpH3dBtkR44YwOPDJYwYCpzYhH EUT3GG8H6iawe4RmLu8Cn1Hu5ErNZ/4gKMIrg86T5enicLDzppJhZi0W3z9ibppdAs/JoLPsn frHEip4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9965 Lines: 312 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 Reviewed-by: Andrey Utkin Tested-by: Andrey Utkin Tested-by: Adam Borowski --- drivers/video/console/Kconfig | 25 +++++++- drivers/video/console/vgacon.c | 142 ++++++++++++++++++++++++++--------------- 2 files changed, 111 insertions(+), 56 deletions(-) diff --git a/drivers/video/console/Kconfig b/drivers/video/console/Kconfig index 38da6e2..c5742d2 100644 --- a/drivers/video/console/Kconfig +++ b/drivers/video/console/Kconfig @@ -43,9 +43,28 @@ 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 feature might break your tool of choice to flush the scrollback + buffer, e.g. clear(1) will work fine but Debian's clear_console(1) + will be broken, which might cause security issues. + You can 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 9a7c2bb..ca23d22 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; @@ -171,74 +171,110 @@ 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) +static void vgacon_scrollback_reset(int vc_num, size_t reset_size) { - if (vgacon_scrollback.data && reset_size > 0) - memset(vgacon_scrollback.data, 0, reset_size); + struct vgacon_scrollback_info *scrollback = &vgacon_scrollbacks[vc_num]; + + if (scrollback->data && reset_size > 0) + memset(scrollback->data, 0, reset_size); - vgacon_scrollback.cnt = 0; - vgacon_scrollback.tail = 0; - vgacon_scrollback.cur = 0; + scrollback->cnt = 0; + scrollback->tail = 0; + scrollback->cur = 0; } -static void vgacon_scrollback_init(int pitch) +static void vgacon_scrollback_init(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; + int pitch = vga_video_num_columns * 2; + size_t size = CONFIG_VGACON_SOFT_SCROLLBACK_SIZE * 1024; + int rows = size / pitch; + void *data; + + data = kmalloc_array(CONFIG_VGACON_SOFT_SCROLLBACK_SIZE, 1024, + GFP_NOWAIT); + + 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; + + vgacon_scrollback_reset(vc_num, size); +} + +static void vgacon_scrollback_switch(int vc_num) +{ +#ifndef CONFIG_VGACON_SOFT_SCROLLBACK_PERSISTENT + vc_num = 0; +#endif + + if (!vgacon_scrollbacks[vc_num].data) { + vgacon_scrollback_init(vc_num); + } else { +#ifdef CONFIG_VGACON_SOFT_SCROLLBACK_PERSISTENT + vgacon_scrollback_cur = &vgacon_scrollbacks[vc_num]; +#else + size_t size = CONFIG_VGACON_SOFT_SCROLLBACK_SIZE * 1024; + + vgacon_scrollback_reset(vc_num, 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); + 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 || + c->vc_num != fg_console) 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; } } @@ -252,41 +288,41 @@ 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) start = 0; - if (start > vgacon_scrollback.cnt) - start = vgacon_scrollback.cnt; + if (start > vgacon_scrollback_cur->cnt) + start = vgacon_scrollback_cur->cnt; if (end < 0) end = 0; - if (end > vgacon_scrollback.cnt) - end = vgacon_scrollback.cnt; + if (end > vgacon_scrollback_cur->cnt) + end = vgacon_scrollback_cur->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 - + ((vgacon_scrollback_cur->cnt - end) * c->vc_size_row); 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; @@ -300,13 +336,13 @@ 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; } @@ -320,13 +356,13 @@ static void vgacon_flush_scrollback(struct vc_data *c) { size_t size = CONFIG_VGACON_SOFT_SCROLLBACK_SIZE * 1024; - if (c->vc_num == fg_console) - vgacon_scrollback_reset(size); + vgacon_scrollback_reset(c->vc_num, size); } #else #define vgacon_scrollback_startup(...) do { } while (0) #define vgacon_scrollback_init(...) do { } while (0) #define vgacon_scrollback_update(...) do { } while (0) +#define vgacon_scrollback_switch(...) do { } while (0) static void vgacon_restore_screen(struct vc_data *c) { @@ -805,7 +841,7 @@ 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_scrollback_switch(c->vc_num); return 0; /* Redrawing not needed */ } -- 2.1.4