* [PATCH v4 2/2] console: Add persistent scrollback buffers for all VGA consoles
2016-11-16 17:40 ` [PATCH v4 1/2] console: Move scrollback data into its own struct Manuel Schölling
@ 2016-11-16 17:40 ` Manuel Schölling
2016-11-16 19:38 ` [PATCH v4 1/2] console: Move scrollback data into its own struct kbuild test robot
2016-11-16 20:12 ` kbuild test robot
2 siblings, 0 replies; 4+ messages in thread
From: Manuel Schölling @ 2016-11-16 17:40 UTC (permalink / raw)
To: plagnioj, tomi.valkeinen
Cc: manuel.schoelling, jslaby, gregkh, linux-fbdev, linux-kernel,
andrey_utkin
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 | 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 d3f823a..90ec0c5 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
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH v4 1/2] console: Move scrollback data into its own struct
2016-11-16 17:40 ` [PATCH v4 1/2] console: Move scrollback data into its own struct Manuel Schölling
2016-11-16 17:40 ` [PATCH v4 2/2] console: Add persistent scrollback buffers for all VGA consoles Manuel Schölling
@ 2016-11-16 19:38 ` kbuild test robot
2016-11-16 20:12 ` kbuild test robot
2 siblings, 0 replies; 4+ messages in thread
From: kbuild test robot @ 2016-11-16 19:38 UTC (permalink / raw)
To: Manuel Schölling
Cc: kbuild-all, plagnioj, tomi.valkeinen, manuel.schoelling, jslaby,
gregkh, linux-fbdev, linux-kernel, andrey_utkin
[-- Attachment #1: Type: text/plain, Size: 2072 bytes --]
Hi Manuel,
[auto build test ERROR on linus/master]
[also build test ERROR on v4.9-rc5 next-20161116]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Manuel-Sch-lling/console-Move-scrollback-data-into-its-own-struct/20161117-024343
config: x86_64-kexec (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
# save the attached .config to linux build tree
make ARCH=x86_64
All errors (new ones prefixed by >>):
drivers/video/console/vgacon.c: In function 'vgacon_scrolldelta':
>> drivers/video/console/vgacon.c:279:14: error: 'vgacon_scrollback_cnt' undeclared (first use in this function)
if (start > vgacon_scrollback_cnt)
^~~~~~~~~~~~~~~~~~~~~
drivers/video/console/vgacon.c:279:14: note: each undeclared identifier is reported only once for each function it appears in
vim +/vgacon_scrollback_cnt +279 drivers/video/console/vgacon.c
adc80b064 Manuel Schölling 2016-11-16 273 start = vgacon_scrollback.cur + lines;
15bdab959 Antonino A. Daplas 2006-03-27 274 end = start + abs(lines);
15bdab959 Antonino A. Daplas 2006-03-27 275
15bdab959 Antonino A. Daplas 2006-03-27 276 if (start < 0)
15bdab959 Antonino A. Daplas 2006-03-27 277 start = 0;
15bdab959 Antonino A. Daplas 2006-03-27 278
15bdab959 Antonino A. Daplas 2006-03-27 @279 if (start > vgacon_scrollback_cnt)
15bdab959 Antonino A. Daplas 2006-03-27 280 start = vgacon_scrollback_cnt;
15bdab959 Antonino A. Daplas 2006-03-27 281
15bdab959 Antonino A. Daplas 2006-03-27 282 if (end < 0)
:::::: The code at line 279 was first introduced by commit
:::::: 15bdab959c9bb909c0317480dd9b35748a8f7887 [PATCH] vgacon: Add support for soft scrollback
:::::: TO: Antonino A. Daplas <adaplas@gmail.com>
:::::: CC: Linus Torvalds <torvalds@g5.osdl.org>
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 24225 bytes --]
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH v4 1/2] console: Move scrollback data into its own struct
2016-11-16 17:40 ` [PATCH v4 1/2] console: Move scrollback data into its own struct Manuel Schölling
2016-11-16 17:40 ` [PATCH v4 2/2] console: Add persistent scrollback buffers for all VGA consoles Manuel Schölling
2016-11-16 19:38 ` [PATCH v4 1/2] console: Move scrollback data into its own struct kbuild test robot
@ 2016-11-16 20:12 ` kbuild test robot
2 siblings, 0 replies; 4+ messages in thread
From: kbuild test robot @ 2016-11-16 20:12 UTC (permalink / raw)
To: Manuel Schölling
Cc: kbuild-all, plagnioj, tomi.valkeinen, manuel.schoelling, jslaby,
gregkh, linux-fbdev, linux-kernel, andrey_utkin
[-- Attachment #1: Type: text/plain, Size: 4104 bytes --]
Hi Manuel,
[auto build test WARNING on linus/master]
[also build test WARNING on v4.9-rc5 next-20161116]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Manuel-Sch-lling/console-Move-scrollback-data-into-its-own-struct/20161117-024343
config: x86_64-randconfig-ne0-11170334 (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
# save the attached .config to linux build tree
make ARCH=x86_64
All warnings (new ones prefixed by >>):
In file included from include/uapi/linux/stddef.h:1:0,
from include/linux/stddef.h:4,
from include/uapi/linux/posix_types.h:4,
from include/uapi/linux/types.h:13,
from include/linux/types.h:5,
from include/linux/list.h:4,
from include/linux/module.h:9,
from drivers/video/console/vgacon.c:36:
drivers/video/console/vgacon.c: In function 'vgacon_scrolldelta':
drivers/video/console/vgacon.c:279:14: error: 'vgacon_scrollback_cnt' undeclared (first use in this function)
if (start > vgacon_scrollback_cnt)
^
include/linux/compiler.h:149:30: note: in definition of macro '__trace_if'
if (__builtin_constant_p(!!(cond)) ? !!(cond) : \
^~~~
>> drivers/video/console/vgacon.c:279:2: note: in expansion of macro 'if'
if (start > vgacon_scrollback_cnt)
^~
drivers/video/console/vgacon.c:279:14: note: each undeclared identifier is reported only once for each function it appears in
if (start > vgacon_scrollback_cnt)
^
include/linux/compiler.h:149:30: note: in definition of macro '__trace_if'
if (__builtin_constant_p(!!(cond)) ? !!(cond) : \
^~~~
>> drivers/video/console/vgacon.c:279:2: note: in expansion of macro 'if'
if (start > vgacon_scrollback_cnt)
^~
vim +/if +279 drivers/video/console/vgacon.c
adc80b064 Manuel Schölling 2016-11-16 263 if (!vgacon_scrollback.data)
97293de97 Jiri Slaby 2016-06-23 264 return;
15bdab959 Antonino A. Daplas 2006-03-27 265
adc80b064 Manuel Schölling 2016-11-16 266 if (!vgacon_scrollback.save) {
15bdab959 Antonino A. Daplas 2006-03-27 267 vgacon_cursor(c, CM_ERASE);
15bdab959 Antonino A. Daplas 2006-03-27 268 vgacon_save_screen(c);
adc80b064 Manuel Schölling 2016-11-16 269 vgacon_scrollback.save = 1;
15bdab959 Antonino A. Daplas 2006-03-27 270 }
15bdab959 Antonino A. Daplas 2006-03-27 271
adc80b064 Manuel Schölling 2016-11-16 272 vgacon_scrollback.restore = 0;
adc80b064 Manuel Schölling 2016-11-16 273 start = vgacon_scrollback.cur + lines;
15bdab959 Antonino A. Daplas 2006-03-27 274 end = start + abs(lines);
15bdab959 Antonino A. Daplas 2006-03-27 275
15bdab959 Antonino A. Daplas 2006-03-27 276 if (start < 0)
15bdab959 Antonino A. Daplas 2006-03-27 277 start = 0;
15bdab959 Antonino A. Daplas 2006-03-27 278
15bdab959 Antonino A. Daplas 2006-03-27 @279 if (start > vgacon_scrollback_cnt)
15bdab959 Antonino A. Daplas 2006-03-27 280 start = vgacon_scrollback_cnt;
15bdab959 Antonino A. Daplas 2006-03-27 281
15bdab959 Antonino A. Daplas 2006-03-27 282 if (end < 0)
15bdab959 Antonino A. Daplas 2006-03-27 283 end = 0;
15bdab959 Antonino A. Daplas 2006-03-27 284
15bdab959 Antonino A. Daplas 2006-03-27 285 if (end > vgacon_scrollback_cnt)
15bdab959 Antonino A. Daplas 2006-03-27 286 end = vgacon_scrollback_cnt;
15bdab959 Antonino A. Daplas 2006-03-27 287
:::::: The code at line 279 was first introduced by commit
:::::: 15bdab959c9bb909c0317480dd9b35748a8f7887 [PATCH] vgacon: Add support for soft scrollback
:::::: TO: Antonino A. Daplas <adaplas@gmail.com>
:::::: CC: Linus Torvalds <torvalds@g5.osdl.org>
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 29872 bytes --]
^ permalink raw reply [flat|nested] 4+ messages in thread