* [PATCH] console: Add persistent scrollback buffers for all VGA consoles
@ 2014-05-30 13:27 Manuel Schölling
2014-05-30 14:28 ` Geert Uytterhoeven
` (2 more replies)
0 siblings, 3 replies; 11+ messages in thread
From: Manuel Schölling @ 2014-05-30 13:27 UTC (permalink / raw)
To: plagnioj
Cc: tomi.valkeinen, geert, broonie, rdunlap, dh.herrmann, airlied,
mtosatti, linux-fbdev, linux-kernel, Manuel Schölling
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.
Signed-off-by: Manuel Schölling <manuel.schoelling@gmx.de>
---
drivers/video/console/Kconfig | 6 +-
drivers/video/console/vgacon.c | 124 ++++++++++++++++++++++++----------------
2 files changed, 79 insertions(+), 51 deletions(-)
diff --git a/drivers/video/console/Kconfig b/drivers/video/console/Kconfig
index fe1cd01..d7ec96c 100644
--- a/drivers/video/console/Kconfig
+++ b/drivers/video/console/Kconfig
@@ -38,14 +38,14 @@ config VGACON_SOFT_SCROLLBACK
RAM to allocate for this buffer. If unsure, say 'N'.
config VGACON_SOFT_SCROLLBACK_SIZE
- int "Scrollback Buffer Size (in KB)"
+ int "Scrollback Buffer Size per console (in KB)"
depends on VGACON_SOFT_SCROLLBACK
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
+ buffer for each VGA console. Each 64KB will give you approximately
+ 16 80x25 screenfuls of scrollback buffer.
config MDA_CONSOLE
depends on !M68K && !PARISC && ISA
diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index 9d8feac..215eafb 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -181,75 +181,101 @@ static inline void vga_set_mem_top(struct vc_data *c)
#ifdef CONFIG_VGACON_SOFT_SCROLLBACK
/* software scrollback */
-static void *vgacon_scrollback;
-static int vgacon_scrollback_tail;
-static int vgacon_scrollback_size;
-static int vgacon_scrollback_rows;
-static int vgacon_scrollback_cnt;
-static int vgacon_scrollback_cur;
-static int vgacon_scrollback_save;
-static int vgacon_scrollback_restore;
-
-static void vgacon_scrollback_init(int pitch)
+struct vgacon_scrollback_info {
+ void *data;
+ int tail;
+ int size;
+ int rows;
+ int cnt;
+ int cur;
+ int save;
+ int restore;
+} vgacon_scrollbacks[MAX_NR_CONSOLES];
+
+static void vgacon_scrollback_init(int vc_num)
{
+ int pitch = vga_video_num_columns * 2;
int rows = CONFIG_VGACON_SOFT_SCROLLBACK_SIZE * 1024/pitch;
+ void *data;
- if (vgacon_scrollback) {
- vgacon_scrollback_cnt = 0;
- vgacon_scrollback_tail = 0;
- vgacon_scrollback_cur = 0;
- vgacon_scrollback_rows = rows - 1;
- vgacon_scrollback_size = rows * pitch;
+ data = kcalloc(CONFIG_VGACON_SOFT_SCROLLBACK_SIZE, 1024, GFP_NOWAIT);
+ if (!data) {
+ pr_warn("VGAcon: failed to allocate memory for scrollback.\n");
+ vgacon_scrollbacks[vc_num].data = NULL;
+ return;
}
+
+ vgacon_scrollbacks[vc_num].data = data;
+ vgacon_scrollbacks[vc_num].cnt = 0;
+ vgacon_scrollbacks[vc_num].tail = 0;
+ vgacon_scrollbacks[vc_num].cur = 0;
+ vgacon_scrollbacks[vc_num].rows = rows - 1;
+ vgacon_scrollbacks[vc_num].size = rows * pitch;
+}
+
+static void vgacon_switch_scrollback(int vc_num)
+{
+ if (!vgacon_scrollbacks[vc_num].data)
+ vgacon_scrollback_init(vc_num);
}
static void vgacon_scrollback_startup(void)
{
- vgacon_scrollback = kcalloc(CONFIG_VGACON_SOFT_SCROLLBACK_SIZE, 1024, GFP_NOWAIT);
- vgacon_scrollback_init(vga_video_num_columns * 2);
+ int i;
+
+ for (i = 0; i < MAX_NR_CONSOLES; ++i)
+ vgacon_scrollbacks[i].data = NULL;
+
+ vgacon_scrollback_init(0);
}
static void vgacon_scrollback_update(struct vc_data *c, int t, int count)
{
+ struct vgacon_scrollback_info *scrollback;
void *p;
- if (!vgacon_scrollback_size || c->vc_num != fg_console)
+ scrollback = &vgacon_scrollbacks[c->vc_num];
+ if (!scrollback->data || !scrollback->size)
return;
p = (void *) (c->vc_origin + t * c->vc_size_row);
while (count--) {
- scr_memcpyw(vgacon_scrollback + vgacon_scrollback_tail,
+ scr_memcpyw(scrollback->data + scrollback->tail,
p, c->vc_size_row);
- vgacon_scrollback_cnt++;
+ scrollback->cnt++;
p += c->vc_size_row;
- vgacon_scrollback_tail += c->vc_size_row;
+ scrollback->tail += c->vc_size_row;
- if (vgacon_scrollback_tail >= vgacon_scrollback_size)
- vgacon_scrollback_tail = 0;
+ if (scrollback->tail >= scrollback->size)
+ scrollback->tail = 0;
- if (vgacon_scrollback_cnt > vgacon_scrollback_rows)
- vgacon_scrollback_cnt = vgacon_scrollback_rows;
+ if (scrollback->cnt > scrollback->rows)
+ scrollback->cnt = scrollback->rows;
- vgacon_scrollback_cur = vgacon_scrollback_cnt;
+ scrollback->cur = scrollback->cnt;
}
}
static void vgacon_restore_screen(struct vc_data *c)
{
- vgacon_scrollback_save = 0;
+ struct vgacon_scrollback_info *scrollback;
+
+ scrollback = &vgacon_scrollbacks[c->vc_num];
+ scrollback->save = 0;
- if (!vga_is_gfx && !vgacon_scrollback_restore) {
+ if (!vga_is_gfx && !scrollback->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;
+ scrollback->restore = 1;
+ scrollback->cur = scrollback->cnt;
}
}
static int vgacon_scrolldelta(struct vc_data *c, int lines)
{
+ struct vgacon_scrollback_info *scrollback;
int start, end, count, soff;
if (!lines) {
@@ -258,41 +284,42 @@ static int vgacon_scrolldelta(struct vc_data *c, int lines)
return 1;
}
- if (!vgacon_scrollback)
+ scrollback = &vgacon_scrollbacks[c->vc_num];
+ if (!scrollback->data)
return 1;
- if (!vgacon_scrollback_save) {
+ if (!scrollback->save) {
vgacon_cursor(c, CM_ERASE);
vgacon_save_screen(c);
- vgacon_scrollback_save = 1;
+ scrollback->save = 1;
}
- vgacon_scrollback_restore = 0;
- start = vgacon_scrollback_cur + lines;
+ scrollback->restore = 0;
+ start = scrollback->cur + lines;
end = start + abs(lines);
if (start < 0)
start = 0;
- if (start > vgacon_scrollback_cnt)
- start = vgacon_scrollback_cnt;
+ if (start > scrollback->cnt)
+ start = scrollback->cnt;
if (end < 0)
end = 0;
- if (end > vgacon_scrollback_cnt)
- end = vgacon_scrollback_cnt;
+ if (end > scrollback->cnt)
+ end = scrollback->cnt;
- vgacon_scrollback_cur = start;
+ scrollback->cur = start;
count = end - start;
- soff = vgacon_scrollback_tail - ((vgacon_scrollback_cnt - end) *
+ soff = scrollback->tail - ((scrollback->cnt - end) *
c->vc_size_row);
soff -= count * c->vc_size_row;
if (soff < 0)
- soff += vgacon_scrollback_size;
+ soff += scrollback->size;
- count = vgacon_scrollback_cnt - start;
+ count = scrollback->cnt - start;
if (count > c->vc_rows)
count = c->vc_rows;
@@ -306,13 +333,13 @@ static int 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 + soff, copysize);
+ copysize = min(count, scrollback->size - soff);
+ scr_memcpyw(d, scrollback->data + soff, copysize);
d += copysize;
count -= copysize;
if (count) {
- scr_memcpyw(d, vgacon_scrollback, count);
+ scr_memcpyw(d, scrollback->data, count);
d += count;
}
@@ -327,6 +354,7 @@ static int 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)
{
@@ -842,7 +870,7 @@ 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 */
}
--
1.7.10.4
^ permalink raw reply related [flat|nested] 11+ messages in thread
* Re: [PATCH] console: Add persistent scrollback buffers for all VGA consoles
2014-05-30 13:27 [PATCH] console: Add persistent scrollback buffers for all VGA consoles Manuel Schölling
@ 2014-05-30 14:28 ` Geert Uytterhoeven
2014-05-30 14:57 ` Manuel Schoelling
2014-05-30 17:06 ` Randy Dunlap
2014-05-30 22:26 ` Jakub Wilk
2 siblings, 1 reply; 11+ messages in thread
From: Geert Uytterhoeven @ 2014-05-30 14:28 UTC (permalink / raw)
To: Manuel Schölling
Cc: Jean-Christophe PLAGNIOL-VILLARD, Tomi Valkeinen, Mark Brown,
Randy Dunlap, David Herrmann, Dave Airlie, Marcelo Tosatti,
Linux Fbdev development list, linux-kernel
Hi Manuel,
On Fri, May 30, 2014 at 3:27 PM, Manuel Schölling
<manuel.schoelling@gmx.de> wrote:
> 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.
Thanks for your patch!
I see two issues with this feature:
1. Before, the single (default 64 KiB) buffer was allocated at startup.
Now you will allocate a buffer each time a new console is opened.
Depending on memory fragmentation, this may fail.
2. People with RAM-constrained systems may not like this.
Can it be a config option?
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] console: Add persistent scrollback buffers for all VGA consoles
2014-05-30 14:28 ` Geert Uytterhoeven
@ 2014-05-30 14:57 ` Manuel Schoelling
0 siblings, 0 replies; 11+ messages in thread
From: Manuel Schoelling @ 2014-05-30 14:57 UTC (permalink / raw)
To: Geert Uytterhoeven
Cc: Jean-Christophe PLAGNIOL-VILLARD, Tomi Valkeinen, Mark Brown,
Randy Dunlap, David Herrmann, Dave Airlie, Marcelo Tosatti,
Linux Fbdev development list, linux-kernel
Hi Geert,
On Fr, 2014-05-30 at 16:28 +0200, Geert Uytterhoeven wrote:
Hi Manuel,
>
> On Fri, May 30, 2014 at 3:27 PM, Manuel Schölling
> <manuel.schoelling@gmx.de> wrote:
> > 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.
>
> Thanks for your patch!
>
> I see two issues with this feature:
> 1. Before, the single (default 64 KiB) buffer was allocated at
startup.
> Now you will allocate a buffer each time a new console is opened.
> Depending on memory fragmentation, this may fail.
Indeed, if allocation fails, scrollbuffer[vc_num]->data will stay NULL
and scrolling will be disabled for that console. Is that ok or would you
prefer another behavior of the kernel?
> 2. People with RAM-constrained systems may not like this.
> Can it be a config option?
Sure, I will add an option for that.
>
> Gr{oetje,eeting}s,
>
> Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 --
geert@linux-m68k.org
>
> In personal conversations with technical people, I call myself a
hacker. But
> when I'm talking to journalists I just say "programmer" or something
like that.
> -- Linus Torvalds
>
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] console: Add persistent scrollback buffers for all VGA consoles
2014-05-30 13:27 [PATCH] console: Add persistent scrollback buffers for all VGA consoles Manuel Schölling
2014-05-30 14:28 ` Geert Uytterhoeven
@ 2014-05-30 17:06 ` Randy Dunlap
2014-05-30 22:26 ` Jakub Wilk
2 siblings, 0 replies; 11+ messages in thread
From: Randy Dunlap @ 2014-05-30 17:06 UTC (permalink / raw)
To: Manuel Schölling, plagnioj
Cc: tomi.valkeinen, geert, broonie, dh.herrmann, airlied, mtosatti,
linux-fbdev, linux-kernel
On 05/30/2014 06:27 AM, Manuel Schölling wrote:
> ---
> drivers/video/console/Kconfig | 6 +-
> drivers/video/console/vgacon.c | 124 ++++++++++++++++++++++++----------------
> 2 files changed, 79 insertions(+), 51 deletions(-)
>
> diff --git a/drivers/video/console/Kconfig b/drivers/video/console/Kconfig
> index fe1cd01..d7ec96c 100644
> --- a/drivers/video/console/Kconfig
> +++ b/drivers/video/console/Kconfig
> @@ -38,14 +38,14 @@ config VGACON_SOFT_SCROLLBACK
> RAM to allocate for this buffer. If unsure, say 'N'.
>
> config VGACON_SOFT_SCROLLBACK_SIZE
> - int "Scrollback Buffer Size (in KB)"
> + int "Scrollback Buffer Size per console (in KB)"
> depends on VGACON_SOFT_SCROLLBACK
> 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
> + buffer for each VGA console. Each 64KB will give you approximately
> + 16 80x25 screenfuls of scrollback buffer.
Nitpick: CodingStyle says to indent help text 1 tab + 2 spaces.
>
> config MDA_CONSOLE
> depends on !M68K && !PARISC && ISA
--
~Randy
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] console: Add persistent scrollback buffers for all VGA consoles
2014-05-30 13:27 [PATCH] console: Add persistent scrollback buffers for all VGA consoles Manuel Schölling
2014-05-30 14:28 ` Geert Uytterhoeven
2014-05-30 17:06 ` Randy Dunlap
@ 2014-05-30 22:26 ` Jakub Wilk
2014-05-31 9:49 ` Manuel Schoelling
2 siblings, 1 reply; 11+ messages in thread
From: Jakub Wilk @ 2014-05-30 22:26 UTC (permalink / raw)
To: Manuel Schölling
Cc: plagnioj, tomi.valkeinen, geert, broonie, rdunlap, dh.herrmann,
airlied, mtosatti, linux-fbdev, linux-kernel
* Manuel Schölling <manuel.schoelling@gmx.de>, 2014-05-30, 15:27:
>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.
Some people rely on this scrollback flushing as a security feature. Is
there even another way to clear the scrollback, than to switch to
another vt and then back again?
Debian ships this:
http://manpages.debian.org/cgi-bin/man.cgi?query=clear_console
https://sources.debian.net/src/bash/4.2%2Bdfsg-0.1/debian/clear_console.c
--
Jakub Wilk
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] console: Add persistent scrollback buffers for all VGA consoles
2014-05-30 22:26 ` Jakub Wilk
@ 2014-05-31 9:49 ` Manuel Schoelling
0 siblings, 0 replies; 11+ messages in thread
From: Manuel Schoelling @ 2014-05-31 9:49 UTC (permalink / raw)
To: Jakub Wilk
Cc: plagnioj, tomi.valkeinen, geert, broonie, rdunlap, dh.herrmann,
airlied, mtosatti, linux-fbdev, linux-kernel
On Sa, 2014-05-31 at 00:26 +0200, Jakub Wilk wrote:
> * Manuel Schölling <manuel.schoelling@gmx.de>, 2014-05-30, 15:27:
> >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.
>
> Some people rely on this scrollback flushing as a security feature. Is
> there even another way to clear the scrollback, than to switch to
> another vt and then back again?
Thanks for raising this security issue! Maybe we should add something
like VT_FLUSH_SCROLLBACK to vt_ioctl()? [1]
I'm open for better ways to flush the scrollback history.
[1] http://lxr.free-electrons.com/source/drivers/tty/vt/vt_ioctl.c#L334
> Debian ships this:
> http://manpages.debian.org/cgi-bin/man.cgi?query=clear_console
> https://sources.debian.net/src/bash/4.2%2Bdfsg-0.1/debian/clear_console.c
>
^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH] console: Add persistent scrollback buffers for all VGA consoles
@ 2016-05-23 21:07 Manuel Schölling
0 siblings, 0 replies; 11+ messages in thread
From: Manuel Schölling @ 2016-05-23 21:07 UTC (permalink / raw)
To: plagnioj
Cc: tomi.valkeinen, sfr, manuel.schoelling, linux-fbdev, linux-kernel
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 <manuel.schoelling@gmx.de>
---
drivers/video/console/Kconfig | 23 +++++-
drivers/video/console/vgacon.c | 172 +++++++++++++++++++++++++++--------------
2 files changed, 134 insertions(+), 61 deletions(-)
diff --git a/drivers/video/console/Kconfig b/drivers/video/console/Kconfig
index 38da6e2..67e52f0 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_FOR_EACH_CONSOLE
+ bool "Persistent Scrollback History for each console"
+ depends on VGACON_SOFT_SCROLLBACK
+ default n
+ help
+ Say Y here if for each VGA console a scrollback buffer should
+ be allocated. The scrollback history will persist when switching
+ between consoles. If you say N here, scrollback is only supported
+ for the active VGA console and scrollback history will be flushed
+ when switching between consoles.
+
+ 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.
+
+ 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 517f565..6c0b9ba 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -1,5 +1,5 @@
/*
- * linux/drivers/video/vgacon.c -- Low level VGA based console driver
+ * linux/drivers/video/console/vgacon.c -- Low level VGA based console driver
*
* Created 28 Sep 1997 by Geert Uytterhoeven
*
@@ -106,12 +106,12 @@ static unsigned char vga_hardscroll_enabled __read_mostly;
static unsigned char vga_hardscroll_user_enable __read_mostly = 1;
static unsigned char vga_font_is_default = 1;
static int vga_vesa_blanked;
-static int vga_palette_blanked;
-static int vga_is_gfx;
-static int vga_512_chars;
-static int vga_video_font_height;
-static int vga_scan_lines __read_mostly;
-static unsigned int vga_rolled_over;
+static int vga_palette_blanked;
+static int vga_is_gfx;
+static int vga_512_chars;
+static int vga_video_font_height;
+static int vga_scan_lines __read_mostly;
+static unsigned int vga_rolled_over;
static int vgacon_text_mode_force;
@@ -182,70 +182,125 @@ static inline void vga_set_mem_top(struct vc_data *c)
#ifdef CONFIG_VGACON_SOFT_SCROLLBACK
/* software scrollback */
-static void *vgacon_scrollback;
-static int vgacon_scrollback_tail;
-static int vgacon_scrollback_size;
-static int vgacon_scrollback_rows;
-static int vgacon_scrollback_cnt;
-static int vgacon_scrollback_cur;
-static int vgacon_scrollback_save;
-static int vgacon_scrollback_restore;
-
-static void vgacon_scrollback_init(int pitch)
+struct vgacon_scrollback_info {
+ void *data;
+ int tail;
+ int size;
+ int rows;
+ int cnt;
+ int cur;
+ int save;
+ int restore;
+};
+static struct vgacon_scrollback_info *vgacon_scrollback_cur;
+#ifdef CONFIG_VGACON_SOFT_SCROLLBACK_FOR_EACH_CONSOLE
+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)
{
- int rows = CONFIG_VGACON_SOFT_SCROLLBACK_SIZE * 1024/pitch;
-
- if (vgacon_scrollback) {
- vgacon_scrollback_cnt = 0;
- vgacon_scrollback_tail = 0;
- vgacon_scrollback_cur = 0;
- vgacon_scrollback_rows = rows - 1;
- vgacon_scrollback_size = rows * pitch;
+ 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;
+
+ 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)
+{
+#ifdef CONFIG_VGACON_SOFT_SCROLLBACK_FOR_EACH_CONSOLE
+ 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 = 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 + 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;
}
}
@@ -259,41 +314,41 @@ static int vgacon_scrolldelta(struct vc_data *c, int lines)
return 1;
}
- if (!vgacon_scrollback)
+ if (!vgacon_scrollback_cur->data)
return 1;
- 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;
+ soff -= ((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;
@@ -307,13 +362,13 @@ static int 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 + 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, count);
+ scr_memcpyw(d, vgacon_scrollback_cur->data, count);
d += count;
}
@@ -328,6 +383,7 @@ static int 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)
{
@@ -843,7 +899,7 @@ 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
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH] console: Add persistent scrollback buffers for all VGA consoles
@ 2016-05-16 11:25 Manuel Schölling
0 siblings, 0 replies; 11+ messages in thread
From: Manuel Schölling @ 2016-05-16 11:25 UTC (permalink / raw)
To: plagnioj
Cc: tomi.valkeinen, sfr, manuel.schoelling, linux-fbdev, linux-kernel
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 <manuel.schoelling@gmx.de>
---
drivers/video/console/Kconfig | 23 +++++-
drivers/video/console/vgacon.c | 172 +++++++++++++++++++++++++++--------------
2 files changed, 134 insertions(+), 61 deletions(-)
diff --git a/drivers/video/console/Kconfig b/drivers/video/console/Kconfig
index 38da6e2..67e52f0 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_FOR_EACH_CONSOLE
+ bool "Persistent Scrollback History for each console"
+ depends on VGACON_SOFT_SCROLLBACK
+ default n
+ help
+ Say Y here if for each VGA console a scrollback buffer should
+ be allocated. The scrollback history will persist when switching
+ between consoles. If you say N here, scrollback is only supported
+ for the active VGA console and scrollback history will be flushed
+ when switching between consoles.
+
+ 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.
+
+ 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 517f565..6c0b9ba 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -1,5 +1,5 @@
/*
- * linux/drivers/video/vgacon.c -- Low level VGA based console driver
+ * linux/drivers/video/console/vgacon.c -- Low level VGA based console driver
*
* Created 28 Sep 1997 by Geert Uytterhoeven
*
@@ -106,12 +106,12 @@ static unsigned char vga_hardscroll_enabled __read_mostly;
static unsigned char vga_hardscroll_user_enable __read_mostly = 1;
static unsigned char vga_font_is_default = 1;
static int vga_vesa_blanked;
-static int vga_palette_blanked;
-static int vga_is_gfx;
-static int vga_512_chars;
-static int vga_video_font_height;
-static int vga_scan_lines __read_mostly;
-static unsigned int vga_rolled_over;
+static int vga_palette_blanked;
+static int vga_is_gfx;
+static int vga_512_chars;
+static int vga_video_font_height;
+static int vga_scan_lines __read_mostly;
+static unsigned int vga_rolled_over;
static int vgacon_text_mode_force;
@@ -182,70 +182,125 @@ static inline void vga_set_mem_top(struct vc_data *c)
#ifdef CONFIG_VGACON_SOFT_SCROLLBACK
/* software scrollback */
-static void *vgacon_scrollback;
-static int vgacon_scrollback_tail;
-static int vgacon_scrollback_size;
-static int vgacon_scrollback_rows;
-static int vgacon_scrollback_cnt;
-static int vgacon_scrollback_cur;
-static int vgacon_scrollback_save;
-static int vgacon_scrollback_restore;
-
-static void vgacon_scrollback_init(int pitch)
+struct vgacon_scrollback_info {
+ void *data;
+ int tail;
+ int size;
+ int rows;
+ int cnt;
+ int cur;
+ int save;
+ int restore;
+};
+static struct vgacon_scrollback_info *vgacon_scrollback_cur;
+#ifdef CONFIG_VGACON_SOFT_SCROLLBACK_FOR_EACH_CONSOLE
+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)
{
- int rows = CONFIG_VGACON_SOFT_SCROLLBACK_SIZE * 1024/pitch;
-
- if (vgacon_scrollback) {
- vgacon_scrollback_cnt = 0;
- vgacon_scrollback_tail = 0;
- vgacon_scrollback_cur = 0;
- vgacon_scrollback_rows = rows - 1;
- vgacon_scrollback_size = rows * pitch;
+ 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;
+
+ 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)
+{
+#ifdef CONFIG_VGACON_SOFT_SCROLLBACK_FOR_EACH_CONSOLE
+ 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 = 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 + 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;
}
}
@@ -259,41 +314,41 @@ static int vgacon_scrolldelta(struct vc_data *c, int lines)
return 1;
}
- if (!vgacon_scrollback)
+ if (!vgacon_scrollback_cur->data)
return 1;
- 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;
+ soff -= ((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;
@@ -307,13 +362,13 @@ static int 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 + 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, count);
+ scr_memcpyw(d, vgacon_scrollback_cur->data, count);
d += count;
}
@@ -328,6 +383,7 @@ static int 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)
{
@@ -843,7 +899,7 @@ 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
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH] console: Add persistent scrollback buffers for all VGA consoles
@ 2016-05-09 10:39 Manuel Schölling
0 siblings, 0 replies; 11+ messages in thread
From: Manuel Schölling @ 2016-05-09 10:39 UTC (permalink / raw)
To: plagnioj
Cc: tomi.valkeinen, sfr, manuel.schoelling, linux-fbdev, linux-kernel
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 <manuel.schoelling@gmx.de>
---
drivers/video/console/Kconfig | 23 +++++-
drivers/video/console/vgacon.c | 172 +++++++++++++++++++++++++++--------------
2 files changed, 134 insertions(+), 61 deletions(-)
diff --git a/drivers/video/console/Kconfig b/drivers/video/console/Kconfig
index 38da6e2..67e52f0 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_FOR_EACH_CONSOLE
+ bool "Persistent Scrollback History for each console"
+ depends on VGACON_SOFT_SCROLLBACK
+ default n
+ help
+ Say Y here if for each VGA console a scrollback buffer should
+ be allocated. The scrollback history will persist when switching
+ between consoles. If you say N here, scrollback is only supported
+ for the active VGA console and scrollback history will be flushed
+ when switching between consoles.
+
+ 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.
+
+ 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 517f565..6c0b9ba 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -1,5 +1,5 @@
/*
- * linux/drivers/video/vgacon.c -- Low level VGA based console driver
+ * linux/drivers/video/console/vgacon.c -- Low level VGA based console driver
*
* Created 28 Sep 1997 by Geert Uytterhoeven
*
@@ -106,12 +106,12 @@ static unsigned char vga_hardscroll_enabled __read_mostly;
static unsigned char vga_hardscroll_user_enable __read_mostly = 1;
static unsigned char vga_font_is_default = 1;
static int vga_vesa_blanked;
-static int vga_palette_blanked;
-static int vga_is_gfx;
-static int vga_512_chars;
-static int vga_video_font_height;
-static int vga_scan_lines __read_mostly;
-static unsigned int vga_rolled_over;
+static int vga_palette_blanked;
+static int vga_is_gfx;
+static int vga_512_chars;
+static int vga_video_font_height;
+static int vga_scan_lines __read_mostly;
+static unsigned int vga_rolled_over;
static int vgacon_text_mode_force;
@@ -182,70 +182,125 @@ static inline void vga_set_mem_top(struct vc_data *c)
#ifdef CONFIG_VGACON_SOFT_SCROLLBACK
/* software scrollback */
-static void *vgacon_scrollback;
-static int vgacon_scrollback_tail;
-static int vgacon_scrollback_size;
-static int vgacon_scrollback_rows;
-static int vgacon_scrollback_cnt;
-static int vgacon_scrollback_cur;
-static int vgacon_scrollback_save;
-static int vgacon_scrollback_restore;
-
-static void vgacon_scrollback_init(int pitch)
+struct vgacon_scrollback_info {
+ void *data;
+ int tail;
+ int size;
+ int rows;
+ int cnt;
+ int cur;
+ int save;
+ int restore;
+};
+static struct vgacon_scrollback_info *vgacon_scrollback_cur;
+#ifdef CONFIG_VGACON_SOFT_SCROLLBACK_FOR_EACH_CONSOLE
+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)
{
- int rows = CONFIG_VGACON_SOFT_SCROLLBACK_SIZE * 1024/pitch;
-
- if (vgacon_scrollback) {
- vgacon_scrollback_cnt = 0;
- vgacon_scrollback_tail = 0;
- vgacon_scrollback_cur = 0;
- vgacon_scrollback_rows = rows - 1;
- vgacon_scrollback_size = rows * pitch;
+ 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;
+
+ 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)
+{
+#ifdef CONFIG_VGACON_SOFT_SCROLLBACK_FOR_EACH_CONSOLE
+ 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 = 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 + 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;
}
}
@@ -259,41 +314,41 @@ static int vgacon_scrolldelta(struct vc_data *c, int lines)
return 1;
}
- if (!vgacon_scrollback)
+ if (!vgacon_scrollback_cur->data)
return 1;
- 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;
+ soff -= ((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;
@@ -307,13 +362,13 @@ static int 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 + 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, count);
+ scr_memcpyw(d, vgacon_scrollback_cur->data, count);
d += count;
}
@@ -328,6 +383,7 @@ static int 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)
{
@@ -843,7 +899,7 @@ 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
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH] console: Add persistent scrollback buffers for all VGA consoles
@ 2016-05-02 17:59 Manuel Schölling
0 siblings, 0 replies; 11+ messages in thread
From: Manuel Schölling @ 2016-05-02 17:59 UTC (permalink / raw)
To: plagnioj
Cc: tomi.valkeinen, sfr, manuel.schoelling, linux-fbdev, linux-kernel
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 <manuel.schoelling@gmx.de>
---
drivers/video/console/Kconfig | 23 +++++-
drivers/video/console/vgacon.c | 172 +++++++++++++++++++++++++++--------------
2 files changed, 134 insertions(+), 61 deletions(-)
diff --git a/drivers/video/console/Kconfig b/drivers/video/console/Kconfig
index 38da6e2..67e52f0 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_FOR_EACH_CONSOLE
+ bool "Persistent Scrollback History for each console"
+ depends on VGACON_SOFT_SCROLLBACK
+ default n
+ help
+ Say Y here if for each VGA console a scrollback buffer should
+ be allocated. The scrollback history will persist when switching
+ between consoles. If you say N here, scrollback is only supported
+ for the active VGA console and scrollback history will be flushed
+ when switching between consoles.
+
+ 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.
+
+ 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 517f565..6c0b9ba 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -1,5 +1,5 @@
/*
- * linux/drivers/video/vgacon.c -- Low level VGA based console driver
+ * linux/drivers/video/console/vgacon.c -- Low level VGA based console driver
*
* Created 28 Sep 1997 by Geert Uytterhoeven
*
@@ -106,12 +106,12 @@ static unsigned char vga_hardscroll_enabled __read_mostly;
static unsigned char vga_hardscroll_user_enable __read_mostly = 1;
static unsigned char vga_font_is_default = 1;
static int vga_vesa_blanked;
-static int vga_palette_blanked;
-static int vga_is_gfx;
-static int vga_512_chars;
-static int vga_video_font_height;
-static int vga_scan_lines __read_mostly;
-static unsigned int vga_rolled_over;
+static int vga_palette_blanked;
+static int vga_is_gfx;
+static int vga_512_chars;
+static int vga_video_font_height;
+static int vga_scan_lines __read_mostly;
+static unsigned int vga_rolled_over;
static int vgacon_text_mode_force;
@@ -182,70 +182,125 @@ static inline void vga_set_mem_top(struct vc_data *c)
#ifdef CONFIG_VGACON_SOFT_SCROLLBACK
/* software scrollback */
-static void *vgacon_scrollback;
-static int vgacon_scrollback_tail;
-static int vgacon_scrollback_size;
-static int vgacon_scrollback_rows;
-static int vgacon_scrollback_cnt;
-static int vgacon_scrollback_cur;
-static int vgacon_scrollback_save;
-static int vgacon_scrollback_restore;
-
-static void vgacon_scrollback_init(int pitch)
+struct vgacon_scrollback_info {
+ void *data;
+ int tail;
+ int size;
+ int rows;
+ int cnt;
+ int cur;
+ int save;
+ int restore;
+};
+static struct vgacon_scrollback_info *vgacon_scrollback_cur;
+#ifdef CONFIG_VGACON_SOFT_SCROLLBACK_FOR_EACH_CONSOLE
+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)
{
- int rows = CONFIG_VGACON_SOFT_SCROLLBACK_SIZE * 1024/pitch;
-
- if (vgacon_scrollback) {
- vgacon_scrollback_cnt = 0;
- vgacon_scrollback_tail = 0;
- vgacon_scrollback_cur = 0;
- vgacon_scrollback_rows = rows - 1;
- vgacon_scrollback_size = rows * pitch;
+ 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;
+
+ 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)
+{
+#ifdef CONFIG_VGACON_SOFT_SCROLLBACK_FOR_EACH_CONSOLE
+ 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 = 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 + 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;
}
}
@@ -259,41 +314,41 @@ static int vgacon_scrolldelta(struct vc_data *c, int lines)
return 1;
}
- if (!vgacon_scrollback)
+ if (!vgacon_scrollback_cur->data)
return 1;
- 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;
+ soff -= ((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;
@@ -307,13 +362,13 @@ static int 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 + 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, count);
+ scr_memcpyw(d, vgacon_scrollback_cur->data, count);
d += count;
}
@@ -328,6 +383,7 @@ static int 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)
{
@@ -843,7 +899,7 @@ 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
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH] console: Add persistent scrollback buffers for all VGA consoles
@ 2016-04-23 10:07 Manuel Schölling
0 siblings, 0 replies; 11+ messages in thread
From: Manuel Schölling @ 2016-04-23 10:07 UTC (permalink / raw)
To: plagnioj
Cc: tomi.valkeinen, sfr, manuel.schoelling, linux-fbdev, linux-kernel
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 <manuel.schoelling@gmx.de>
---
drivers/video/console/Kconfig | 23 +++++-
drivers/video/console/vgacon.c | 172 +++++++++++++++++++++++++++--------------
2 files changed, 134 insertions(+), 61 deletions(-)
diff --git a/drivers/video/console/Kconfig b/drivers/video/console/Kconfig
index 38da6e2..67e52f0 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_FOR_EACH_CONSOLE
+ bool "Persistent Scrollback History for each console"
+ depends on VGACON_SOFT_SCROLLBACK
+ default n
+ help
+ Say Y here if for each VGA console a scrollback buffer should
+ be allocated. The scrollback history will persist when switching
+ between consoles. If you say N here, scrollback is only supported
+ for the active VGA console and scrollback history will be flushed
+ when switching between consoles.
+
+ 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.
+
+ 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 517f565..6c0b9ba 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -1,5 +1,5 @@
/*
- * linux/drivers/video/vgacon.c -- Low level VGA based console driver
+ * linux/drivers/video/console/vgacon.c -- Low level VGA based console driver
*
* Created 28 Sep 1997 by Geert Uytterhoeven
*
@@ -106,12 +106,12 @@ static unsigned char vga_hardscroll_enabled __read_mostly;
static unsigned char vga_hardscroll_user_enable __read_mostly = 1;
static unsigned char vga_font_is_default = 1;
static int vga_vesa_blanked;
-static int vga_palette_blanked;
-static int vga_is_gfx;
-static int vga_512_chars;
-static int vga_video_font_height;
-static int vga_scan_lines __read_mostly;
-static unsigned int vga_rolled_over;
+static int vga_palette_blanked;
+static int vga_is_gfx;
+static int vga_512_chars;
+static int vga_video_font_height;
+static int vga_scan_lines __read_mostly;
+static unsigned int vga_rolled_over;
static int vgacon_text_mode_force;
@@ -182,70 +182,125 @@ static inline void vga_set_mem_top(struct vc_data *c)
#ifdef CONFIG_VGACON_SOFT_SCROLLBACK
/* software scrollback */
-static void *vgacon_scrollback;
-static int vgacon_scrollback_tail;
-static int vgacon_scrollback_size;
-static int vgacon_scrollback_rows;
-static int vgacon_scrollback_cnt;
-static int vgacon_scrollback_cur;
-static int vgacon_scrollback_save;
-static int vgacon_scrollback_restore;
-
-static void vgacon_scrollback_init(int pitch)
+struct vgacon_scrollback_info {
+ void *data;
+ int tail;
+ int size;
+ int rows;
+ int cnt;
+ int cur;
+ int save;
+ int restore;
+};
+static struct vgacon_scrollback_info *vgacon_scrollback_cur;
+#ifdef CONFIG_VGACON_SOFT_SCROLLBACK_FOR_EACH_CONSOLE
+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)
{
- int rows = CONFIG_VGACON_SOFT_SCROLLBACK_SIZE * 1024/pitch;
-
- if (vgacon_scrollback) {
- vgacon_scrollback_cnt = 0;
- vgacon_scrollback_tail = 0;
- vgacon_scrollback_cur = 0;
- vgacon_scrollback_rows = rows - 1;
- vgacon_scrollback_size = rows * pitch;
+ 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;
+
+ 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)
+{
+#ifdef CONFIG_VGACON_SOFT_SCROLLBACK_FOR_EACH_CONSOLE
+ 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 = 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 + 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;
}
}
@@ -259,41 +314,41 @@ static int vgacon_scrolldelta(struct vc_data *c, int lines)
return 1;
}
- if (!vgacon_scrollback)
+ if (!vgacon_scrollback_cur->data)
return 1;
- 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;
+ soff -= ((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;
@@ -307,13 +362,13 @@ static int 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 + 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, count);
+ scr_memcpyw(d, vgacon_scrollback_cur->data, count);
d += count;
}
@@ -328,6 +383,7 @@ static int 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)
{
@@ -843,7 +899,7 @@ 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
^ permalink raw reply related [flat|nested] 11+ messages in thread
end of thread, other threads:[~2016-05-23 21:07 UTC | newest]
Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-05-30 13:27 [PATCH] console: Add persistent scrollback buffers for all VGA consoles Manuel Schölling
2014-05-30 14:28 ` Geert Uytterhoeven
2014-05-30 14:57 ` Manuel Schoelling
2014-05-30 17:06 ` Randy Dunlap
2014-05-30 22:26 ` Jakub Wilk
2014-05-31 9:49 ` Manuel Schoelling
2016-04-23 10:07 Manuel Schölling
2016-05-02 17:59 Manuel Schölling
2016-05-09 10:39 Manuel Schölling
2016-05-16 11:25 Manuel Schölling
2016-05-23 21:07 Manuel Schölling
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