| Message ID | cover.1710252966.git.legion@kernel.org |
|---|---|
| Headers | show |
| Series | VT: Add ability to get font requirements | expand |
Hi, On 02. 04. 24, 12:32, Alexey Gladkov wrote: > Each driver has its own restrictions on font size. There is currently no > way to understand what the requirements are. The new ioctl allows > userspace to get the minmum and maximum font size values. minimum > Acked-by: Helge Deller <deller@gmx.de> > Signed-off-by: Alexey Gladkov <legion@kernel.org> > --- > drivers/tty/vt/vt.c | 24 ++++++++++++++++++++++++ > drivers/tty/vt/vt_ioctl.c | 13 +++++++++++++ > include/linux/console.h | 2 ++ > include/linux/vt_kern.h | 1 + > include/uapi/linux/kd.h | 13 ++++++++++++- > 5 files changed, 52 insertions(+), 1 deletion(-) > > diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c > index 156efda7c80d..8c2a3d98b5ec 100644 > --- a/drivers/tty/vt/vt.c > +++ b/drivers/tty/vt/vt.c > @@ -4680,6 +4680,30 @@ int con_font_op(struct vc_data *vc, struct console_font_op *op) > return -ENOSYS; > } > > +int con_font_info(struct vc_data *vc, struct console_font_info *info) > +{ > + int rc = -EINVAL; This initialization appears to be unneeded. > + > + info->min_height = 0; > + info->max_height = max_font_height; > + > + info->min_width = 0; > + info->max_width = max_font_width; > + > + info->flags = KD_FONT_INFO_FLAG_LOW_SIZE | KD_FONT_INFO_FLAG_HIGH_SIZE; > + > + console_lock(); > + if (vc->vc_mode != KD_TEXT) > + rc = -EINVAL; > + else if (vc->vc_sw->con_font_info) > + rc = vc->vc_sw->con_font_info(vc, info); > + else > + rc = -ENOSYS; > + console_unlock(); > + > + return rc; > +} > + > /* > * Interface exported to selection and vcs. > */ > diff --git a/drivers/tty/vt/vt_ioctl.c b/drivers/tty/vt/vt_ioctl.c > index 8c685b501404..b3b4e4b69366 100644 > --- a/drivers/tty/vt/vt_ioctl.c > +++ b/drivers/tty/vt/vt_ioctl.c > @@ -479,6 +479,19 @@ static int vt_k_ioctl(struct tty_struct *tty, unsigned int cmd, > break; > } > > + case KDFONTINFO: { > + struct console_font_info fnt_info; > + > + if (copy_from_user(&fnt_info, up, sizeof(fnt_info))) > + return -EFAULT; Who uses the copied values? > + ret = con_font_info(vc, &fnt_info); > + if (ret) > + return ret; > + if (copy_to_user(up, &fnt_info, sizeof(fnt_info))) We should do the preferred sizeof(*up) here... > + return -EFAULT; > + break; > + } > + > default: > return -ENOIOCTLCMD; > } ... > --- a/include/uapi/linux/kd.h > +++ b/include/uapi/linux/kd.h > @@ -183,8 +183,19 @@ struct console_font { > > #define KD_FONT_FLAG_DONT_RECALC 1 /* Don't recalculate hw charcell size [compat] */ > > +#define KDFONTINFO 0x4B73 /* font information */ Why not properly define the number using IOC() et al.? K (that 0x4b) is even reserved for kd.h. > +#define KD_FONT_INFO_FLAG_LOW_SIZE (1U << 0) /* 256 */ > +#define KD_FONT_INFO_FLAG_HIGH_SIZE (1U << 1) /* 512 */ _BITUL() > +struct console_font_info { > + unsigned int min_width, min_height; /* minimal font size */ > + unsigned int max_width, max_height; /* maximum font size */ > + unsigned int flags; /* KD_FONT_INFO_FLAG_* */ This does not look like a well-defined™ and extendable uapi structure. While it won't change anything here, still use fixed-length __u32. And you should perhaps add some reserved fields. Do not repeat the same mistakes as your predecessors with the current kd uapi. > +}; thanks,
On Tue, Apr 02, 2024 at 01:02:20PM +0200, Jiri Slaby wrote: > Hi, > > On 02. 04. 24, 12:32, Alexey Gladkov wrote: > > Each driver has its own restrictions on font size. There is currently no > > way to understand what the requirements are. The new ioctl allows > > userspace to get the minmum and maximum font size values. > > minimum Typo. Sorry. > > Acked-by: Helge Deller <deller@gmx.de> > > Signed-off-by: Alexey Gladkov <legion@kernel.org> > > --- > > drivers/tty/vt/vt.c | 24 ++++++++++++++++++++++++ > > drivers/tty/vt/vt_ioctl.c | 13 +++++++++++++ > > include/linux/console.h | 2 ++ > > include/linux/vt_kern.h | 1 + > > include/uapi/linux/kd.h | 13 ++++++++++++- > > 5 files changed, 52 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c > > index 156efda7c80d..8c2a3d98b5ec 100644 > > --- a/drivers/tty/vt/vt.c > > +++ b/drivers/tty/vt/vt.c > > @@ -4680,6 +4680,30 @@ int con_font_op(struct vc_data *vc, struct console_font_op *op) > > return -ENOSYS; > > } > > > > +int con_font_info(struct vc_data *vc, struct console_font_info *info) > > +{ > > + int rc = -EINVAL; > > This initialization appears to be unneeded. > > > + > > + info->min_height = 0; > > + info->max_height = max_font_height; > > + > > + info->min_width = 0; > > + info->max_width = max_font_width; > > + > > + info->flags = KD_FONT_INFO_FLAG_LOW_SIZE | KD_FONT_INFO_FLAG_HIGH_SIZE; > > + > > + console_lock(); > > + if (vc->vc_mode != KD_TEXT) > > + rc = -EINVAL; > > + else if (vc->vc_sw->con_font_info) > > + rc = vc->vc_sw->con_font_info(vc, info); > > + else > > + rc = -ENOSYS; > > + console_unlock(); > > + > > + return rc; > > +} > > + > > /* > > * Interface exported to selection and vcs. > > */ > > diff --git a/drivers/tty/vt/vt_ioctl.c b/drivers/tty/vt/vt_ioctl.c > > index 8c685b501404..b3b4e4b69366 100644 > > --- a/drivers/tty/vt/vt_ioctl.c > > +++ b/drivers/tty/vt/vt_ioctl.c > > @@ -479,6 +479,19 @@ static int vt_k_ioctl(struct tty_struct *tty, unsigned int cmd, > > break; > > } > > > > + case KDFONTINFO: { > > + struct console_font_info fnt_info; > > + > > + if (copy_from_user(&fnt_info, up, sizeof(fnt_info))) > > + return -EFAULT; > > Who uses the copied values? No one. I did it by analogy with KDFONTOP. Thanks! > > + ret = con_font_info(vc, &fnt_info); > > + if (ret) > > + return ret; > > + if (copy_to_user(up, &fnt_info, sizeof(fnt_info))) > > We should do the preferred sizeof(*up) here... > > > + return -EFAULT; > > + break; > > + } > > + > > default: > > return -ENOIOCTLCMD; > > } > ... > > --- a/include/uapi/linux/kd.h > > +++ b/include/uapi/linux/kd.h > > @@ -183,8 +183,19 @@ struct console_font { > > > > #define KD_FONT_FLAG_DONT_RECALC 1 /* Don't recalculate hw charcell size [compat] */ > > > > +#define KDFONTINFO 0x4B73 /* font information */ > > Why not properly define the number using IOC() et al.? K (that 0x4b) is > even reserved for kd.h. I just did the same as the numbers above. This entire header does not use IOC(). Should I convert this header as a separate commit? > > +#define KD_FONT_INFO_FLAG_LOW_SIZE (1U << 0) /* 256 */ > > +#define KD_FONT_INFO_FLAG_HIGH_SIZE (1U << 1) /* 512 */ > > _BITUL() Make sense. I will use it. > > +struct console_font_info { > > + unsigned int min_width, min_height; /* minimal font size */ > > + unsigned int max_width, max_height; /* maximum font size */ > > + unsigned int flags; /* KD_FONT_INFO_FLAG_* */ > > This does not look like a well-defined™ and extendable uapi structure. > While it won't change anything here, still use fixed-length __u32. > > And you should perhaps add some reserved fields. Do not repeat the same > mistakes as your predecessors with the current kd uapi. I thought about it, but I thought it would be overengineering. Can you suggest how best to do this?
On 02. 04. 24, 15:19, Alexey Gladkov wrote: >>> --- a/include/uapi/linux/kd.h >>> +++ b/include/uapi/linux/kd.h ... >>> +struct console_font_info { >>> + unsigned int min_width, min_height; /* minimal font size */ >>> + unsigned int max_width, max_height; /* maximum font size */ >>> + unsigned int flags; /* KD_FONT_INFO_FLAG_* */ >> >> This does not look like a well-defined™ and extendable uapi structure. >> While it won't change anything here, still use fixed-length __u32. >> >> And you should perhaps add some reserved fields. Do not repeat the same >> mistakes as your predecessors with the current kd uapi. > > I thought about it, but I thought it would be overengineering. It would not. UAPI structs are set in stone once released. And in this case, it's likely you would want to know more info about fonts in the future. > Can you suggest how best to do this? Given you have flags in there already (to state that the structure contains more), just add an array of u32 reserved[] space. 3 or 5, I would say (to align the struct to 64bit). thanks,
On Wed, Apr 03, 2024 at 07:27:55AM +0200, Jiri Slaby wrote: > On 02. 04. 24, 15:19, Alexey Gladkov wrote: > >>> --- a/include/uapi/linux/kd.h > >>> +++ b/include/uapi/linux/kd.h > ... > >>> +struct console_font_info { > >>> + unsigned int min_width, min_height; /* minimal font size */ > >>> + unsigned int max_width, max_height; /* maximum font size */ > >>> + unsigned int flags; /* KD_FONT_INFO_FLAG_* */ > >> > >> This does not look like a well-defined™ and extendable uapi structure. > >> While it won't change anything here, still use fixed-length __u32. > >> > >> And you should perhaps add some reserved fields. Do not repeat the same > >> mistakes as your predecessors with the current kd uapi. > > > > I thought about it, but I thought it would be overengineering. > > It would not. UAPI structs are set in stone once released. > > And in this case, it's likely you would want to know more info about > fonts in the future. > > > Can you suggest how best to do this? > > Given you have flags in there already (to state that the structure > contains more), just add an array of u32 reserved[] space. 3 or 5, I > would say (to align the struct to 64bit). struct console_font_info { __u32 min_width, min_height; /* minimal font size */ __u32 max_width, max_height; /* maximum font size */ __u32 flags; /* KD_FONT_INFO_FLAG_* */ __u32 reserved[5]; /* This field is reserved forfuture use. Must be 0. */ }; So, struct should be like this ? I wouldn't add the version to the flags. Maybe it would be better to add a separate field with the version?
On Wed, Apr 10, 2024 at 06:29:19PM +0200, Alexey Gladkov wrote: > On Wed, Apr 03, 2024 at 07:27:55AM +0200, Jiri Slaby wrote: > > On 02. 04. 24, 15:19, Alexey Gladkov wrote: > > >>> --- a/include/uapi/linux/kd.h > > >>> +++ b/include/uapi/linux/kd.h > > ... > > >>> +struct console_font_info { > > >>> + unsigned int min_width, min_height; /* minimal font size */ > > >>> + unsigned int max_width, max_height; /* maximum font size */ > > >>> + unsigned int flags; /* KD_FONT_INFO_FLAG_* */ > > >> > > >> This does not look like a well-defined™ and extendable uapi structure. > > >> While it won't change anything here, still use fixed-length __u32. > > >> > > >> And you should perhaps add some reserved fields. Do not repeat the same > > >> mistakes as your predecessors with the current kd uapi. > > > > > > I thought about it, but I thought it would be overengineering. > > > > It would not. UAPI structs are set in stone once released. > > > > And in this case, it's likely you would want to know more info about > > fonts in the future. > > > > > Can you suggest how best to do this? > > > > Given you have flags in there already (to state that the structure > > contains more), just add an array of u32 reserved[] space. 3 or 5, I > > would say (to align the struct to 64bit). > > struct console_font_info { > __u32 min_width, min_height; /* minimal font size */ > __u32 max_width, max_height; /* maximum font size */ > __u32 flags; /* KD_FONT_INFO_FLAG_* */ > __u32 reserved[5]; /* This field is reserved forfuture use. Must be 0. */ > }; > > So, struct should be like this ? > > I wouldn't add the version to the flags. Maybe it would be better to add a > separate field with the version? Versions do not work for ioctls, just use flags for stuff. And you might want to put flags first? thanks, greg k-h
From: Alexey Gladkov <legion@kernel.org> We now have KD_FONT_OP_SET_TALL, but in fact such large fonts cannot be loaded. No console driver supports tall fonts. Unfortunately, userspace cannot distinguish the lack of support in the driver from errors in the font itself. In all cases, EINVAL will be returned. This patchset adds a separate ioctl to obtain the font parameters supported by the console driver. v3: * Added the use of the in_range macro. * Squashed the commits that add ioctl to console divers. v2: * Instead of the KDFONTOP extension, a new ioctl has been added to obtain font information. --- Alexey Gladkov (2): VT: Add KDFONTINFO ioctl VT: Allow to get max font width and height drivers/tty/vt/vt.c | 24 ++++++++++++++++++++++++ drivers/tty/vt/vt_ioctl.c | 13 +++++++++++++ drivers/video/console/newport_con.c | 21 +++++++++++++++++---- drivers/video/console/sticon.c | 25 +++++++++++++++++++++++-- drivers/video/console/vgacon.c | 21 ++++++++++++++++++++- drivers/video/fbdev/core/fbcon.c | 22 +++++++++++++++++++++- include/linux/console.h | 2 ++ include/linux/vt_kern.h | 1 + include/uapi/linux/kd.h | 13 ++++++++++++- 9 files changed, 133 insertions(+), 9 deletions(-)