Add Kconfig option CONFIG_FB_DEVICE and make the virtual fbdev
device optional. If the new option has not been selected, fbdev
does not create files in devfs, sysfs or procfs.
Most modern Linux systems run a DRM-based graphics stack that uses
the kernel's framebuffer console, but has otherwise deprecated fbdev
support. Yet fbdev userspace interfaces are still present.
The option makes it possible to use the fbdev subsystem as console
implementation without support for userspace. This closes potential
entry points to manipulate kernel or I/O memory via framebuffers. It
also prevents the execution of driver code via ioctl or sysfs, both
of which might allow malicious software to exploit bugs in the fbdev
code.
A small number of fbdev drivers require struct fbinfo.dev to be
initialized, usually for the support of sysfs interface. Make these
drivers depend on FB_DEVICE. They can later be fixed if necessary.
v3:
* effect -> affect in Kconfig help (Daniel)
v2:
* set FB_DEVICE default to y (Geert)
* comment on {get,put}_device() (Sam)
* Kconfig fixes (Sam)
* add TODO item about FB_DEVICE dependencies (Sam)
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230613110953.24176-39-tzimmermann@suse.de
Move fbdev's procfs code into a separate file and contain it in
init and cleanup helpers. For the cleanup, replace remove_proc_entry()
with proc_remove(). It is equivalent in functionality, but looks
more like an inverse of proc_create_seq().
v2:
* document proc_remove() usage (Sam)
* revert unrelated removal of for_each_registered_fb()
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230613110953.24176-36-tzimmermann@suse.de
Move the logic to create and destroy fbdev devices into the new
helpers fb_device_create() and fb_device_destroy().
There was a call to fb_cleanup_device() in do_unregister_framebuffer()
that was too late. The device had already been removed at this point.
Move the call into fb_device_destroy().
Declare the helpers in the new internal header file fb_internal.h, as
they are only used within the fbdev core module.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230613110953.24176-35-tzimmermann@suse.de
Replace the use of the fbdev software device, stored in struct
fb_info.dev, with the hardware device from struct fb_info.device
in load_waveform(). The device is only used for printing errors
with dev_err().
This change aligns load_waveform() with the rest of the driver and
prepares fbdev for making struct fb_info.dev optional.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230613110953.24176-18-tzimmermann@suse.de
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.
Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Helge Deller <deller@gmx.de>
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.
Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Helge Deller <deller@gmx.de>
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.
Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Helge Deller <deller@gmx.de>
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.
Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Helge Deller <deller@gmx.de>
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.
Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Helge Deller <deller@gmx.de>
The driver core never calls a remove callback with the platform_device
pointer being NULL. So the check for this condition can just be dropped.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Helge Deller <deller@gmx.de>
After commit b8a1a4cd5a ("i2c: Provide a temporary .probe_new()
call-back type"), all drivers being converted to .probe_new() and then
03c835f498 ("i2c: Switch .probe() to not take an id parameter")
convert back to (the new) .probe() to be able to eventually drop
.probe_new() from struct i2c_driver.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Helge Deller <deller@gmx.de>
Use the newly introduced usb_control_msg_send() instead of usb_control_msg()
when selecting the channel.
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Helge Deller <deller@gmx.de>
The syzbot fuzzer detected a problem in the udlfb driver, caused by an
endpoint not having the expected type:
usb 1-1: Read EDID byte 0 failed: -71
usb 1-1: Unable to get valid EDID from device/display
------------[ cut here ]------------
usb 1-1: BOGUS urb xfer, pipe 3 != type 1
WARNING: CPU: 0 PID: 9 at drivers/usb/core/urb.c:504 usb_submit_urb+0xed6/0x1880
drivers/usb/core/urb.c:504
Modules linked in:
CPU: 0 PID: 9 Comm: kworker/0:1 Not tainted
6.4.0-rc1-syzkaller-00016-ga4422ff22142 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google
04/28/2023
Workqueue: usb_hub_wq hub_event
RIP: 0010:usb_submit_urb+0xed6/0x1880 drivers/usb/core/urb.c:504
...
Call Trace:
<TASK>
dlfb_submit_urb+0x92/0x180 drivers/video/fbdev/udlfb.c:1980
dlfb_set_video_mode+0x21f0/0x2950 drivers/video/fbdev/udlfb.c:315
dlfb_ops_set_par+0x2a7/0x8d0 drivers/video/fbdev/udlfb.c:1111
dlfb_usb_probe+0x149a/0x2710 drivers/video/fbdev/udlfb.c:1743
The current approach for this issue failed to catch the problem
because it only checks for the existence of a bulk-OUT endpoint; it
doesn't check whether this endpoint is the one that the driver will
actually use.
We can fix the problem by instead checking that the endpoint used by
the driver does exist and is bulk-OUT.
Reported-and-tested-by: syzbot+0e22d63dcebb802b9bc8@syzkaller.appspotmail.com
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Pavel Skripkin <paskripkin@gmail.com>
Fixes: aaf7dbe073 ("video: fbdev: udlfb: properly check endpoint type")
Signed-off-by: Helge Deller <deller@gmx.de>
Building with W=1 shows that a header needs to be included to
make the prototypes visible:
drivers/video/fbdev/i810/i810_dvt.c:194:6: error: no previous prototype for 'round_off_xres' [-Werror=missing-prototypes]
drivers/video/fbdev/i810/i810_dvt.c:233:6: error: no previous prototype for 'i810fb_encode_registers' [-Werror=missing-prototypes]
drivers/video/fbdev/i810/i810_dvt.c:245:6: error: no previous prototype for 'i810fb_fill_var_timings' [-Werror=missing-prototypes]
drivers/video/fbdev/i810/i810_dvt.c:279:5: error: no previous prototype for 'i810_get_watermark' [-Werror=missing-prototypes]
Adding the header leads to another warning from a mismatched
prototype, so fix this as well:
drivers/video/fbdev/i810/i810_dvt.c:280:5: error: conflicting types for 'i810_get_watermark'; have 'u32(struct fb_var_screeninfo *,
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Helge Deller <deller@gmx.de>
