[PATCH 30/33] fbcon: Call con2fb_map functions directly

Daniel Vetter
2019-05-24T08:53:51Z

These are actually fbcon ioctls which just happen to be exposed
through /dev/fb*. They completely ignore which fb_info they're called
on, and I think the userspace tool even hardcodes to /dev/fb0.

Hence just forward the entire thing to fbcon.c wholesale.

Note that this patch drops the fb_lock/unlock on the set side. Since
the ioctl can operate on any fb (as passed in through
con2fb.framebuffer) this is bogus. Also note that fbcon.c in general
never calls fb_lock on anything, so this has been badly broken
already.

With this the last user of the fbcon notifier callback is gone, and we
can garbage collect that too.

v2: add missing uaccess.h include (alpha fails to compile otherwise),
reported by kbuild.

v3: Remember to also drop the #defines (Maarten)

v4: Add the static inline to dummy functions.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Yisheng Xie <ysxie@foxmail.com>
Cc: "Michał Mirosław" <mirq-linux@rere.qmqm.pl>
Cc: Peter Rosin <peda@axentia.se>
Cc: Mikulas Patocka <mpatocka@redhat.com>
---
drivers/video/fbdev/core/fbcon.c | 59 +++++++++++++++++++-------------
drivers/video/fbdev/core/fbmem.c | 34 ++----------------
include/linux/fb.h | 4 ---
include/linux/fbcon.h | 4 +++
4 files changed, 42 insertions(+), 59 deletions(-)

diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index e08e984e2511..6a4bbb8407c0 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -76,6 +76,7 @@
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/crc32.h> /* For counting font checksums */
+#include <linux/uaccess.h>
#include <asm/fb.h>
#include <asm/irq.h>

@@ -3318,29 +3319,47 @@ void fbcon_get_requirement(struct fb_info *info,
}
}

-static int fbcon_event_notify(struct notifier_block *self,
- unsigned long action, void *data)
+int fbcon_set_con2fb_map_ioctl(void __user *argp)
{
- struct fb_event *event = data;
- struct fb_info *info = event->info;
- struct fb_con2fbmap *con2fb;
- int idx, ret = 0;
+ struct fb_con2fbmap con2fb;
+ int ret;

- switch(action) {
- case FB_EVENT_SET_CONSOLE_MAP:
- /* called with console lock held */
- con2fb = event->data;
- ret = set_con2fb_map(con2fb->console - 1,
- con2fb->framebuffer, 1);
- break;
- case FB_EVENT_GET_CONSOLE_MAP:
- con2fb = event->data;
- con2fb->framebuffer = con2fb_map[con2fb->console - 1];
- break;
+ if (copy_from_user(&con2fb, argp, sizeof(con2fb)))
+ return -EFAULT;
+ if (con2fb.console < 1 || con2fb.console > MAX_NR_CONSOLES)
+ return -EINVAL;
+ if (con2fb.framebuffer >= FB_MAX)
+ return -EINVAL;
+ if (!registered_fb[con2fb.framebuffer])
+ request_module("fb%d", con2fb.framebuffer);
+ if (!registered_fb[con2fb.framebuffer]) {
+ return -EINVAL;
}
+
+ console_lock();
+ ret = set_con2fb_map(con2fb.console - 1,
+ con2fb.framebuffer, 1);
+ console_unlock();
+
return ret;
}

+int fbcon_get_con2fb_map_ioctl(void __user *argp)
+{
+ struct fb_con2fbmap con2fb;
+
+ if (copy_from_user(&con2fb, argp, sizeof(con2fb)))
+ return -EFAULT;
+ if (con2fb.console < 1 || con2fb.console > MAX_NR_CONSOLES)
+ return -EINVAL;
+
+ console_lock();
+ con2fb.framebuffer = con2fb_map[con2fb.console - 1];
+ console_unlock();
+
+ return copy_to_user(argp, &con2fb, sizeof(con2fb)) ? -EFAULT : 0;
+}
+
/*
* The console `switch' structure for the frame buffer based console
*/
@@ -3372,10 +3391,6 @@ static const struct consw fb_con = {
.con_debug_leave = fbcon_debug_leave,
};

-static struct notifier_block fbcon_event_notifier = {
- .notifier_call = fbcon_event_notify,
-};
-
static ssize_t store_rotate(struct device *device,
struct device_attribute *attr, const char *buf,
size_t count)
@@ -3648,7 +3663,6 @@ void __init fb_console_init(void)
int i;

console_lock();
- fb_register_client(&fbcon_event_notifier);
fbcon_device = device_create(fb_class, NULL, MKDEV(0, 0), NULL,
"fbcon");

@@ -3684,7 +3698,6 @@ static void __exit fbcon_deinit_device(void)
void __exit fb_console_exit(void)
{
console_lock();
- fb_unregister_client(&fbcon_event_notifier);
fbcon_deinit_device();
device_destroy(fb_class, MKDEV(0, 0));
fbcon_exit();
diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index dd1a708df1a7..64dd732021d8 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1092,10 +1092,8 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
struct fb_ops *fb;
struct fb_var_screeninfo var;
struct fb_fix_screeninfo fix;
- struct fb_con2fbmap con2fb;
struct fb_cmap cmap_from;
struct fb_cmap_user cmap;
- struct fb_event event;
void __user *argp = (void __user *)arg;
long ret = 0;

@@ -1157,38 +1155,10 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
ret = -EINVAL;
break;
case FBIOGET_CON2FBMAP:
- if (copy_from_user(&con2fb, argp, sizeof(con2fb)))
- return -EFAULT;
- if (con2fb.console < 1 || con2fb.console > MAX_NR_CONSOLES)
- return -EINVAL;
- con2fb.framebuffer = -1;
- event.data = &con2fb;
- lock_fb_info(info);
- event.info = info;
- fb_notifier_call_chain(FB_EVENT_GET_CONSOLE_MAP, &event);
- unlock_fb_info(info);
- ret = copy_to_user(argp, &con2fb, sizeof(con2fb)) ? -EFAULT : 0;
+ ret = fbcon_get_con2fb_map_ioctl(argp);
break;
case FBIOPUT_CON2FBMAP:
- if (copy_from_user(&con2fb, argp, sizeof(con2fb)))
- return -EFAULT;
- if (con2fb.console < 1 || con2fb.console > MAX_NR_CONSOLES)
- return -EINVAL;
- if (con2fb.framebuffer >= FB_MAX)
- return -EINVAL;
- if (!registered_fb[con2fb.framebuffer])
- request_module("fb%d", con2fb.framebuffer);
- if (!registered_fb[con2fb.framebuffer]) {
- ret = -EINVAL;
- break;
- }
- event.data = &con2fb;
- console_lock();
- lock_fb_info(info);
- event.info = info;
- ret = fb_notifier_call_chain(FB_EVENT_SET_CONSOLE_MAP, &event);
- unlock_fb_info(info);
- console_unlock();
+ ret = fbcon_set_con2fb_map_ioctl(argp);
break;
case FBIOBLANK:
console_lock();
diff --git a/include/linux/fb.h b/include/linux/fb.h
index 25e4b885f5b3..303771264644 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -133,10 +133,6 @@ struct fb_cursor_user {
#define FB_EVENT_FB_UNREGISTERED 0x06
#endif

-/* CONSOLE-SPECIFIC: get console to framebuffer mapping */
-#define FB_EVENT_GET_CONSOLE_MAP 0x07
-/* CONSOLE-SPECIFIC: set console to framebuffer mapping */
-#define FB_EVENT_SET_CONSOLE_MAP 0x08
/* A display blank is requested */
#define FB_EVENT_BLANK 0x09
/* A hardware display blank early change occurred */
diff --git a/include/linux/fbcon.h b/include/linux/fbcon.h
index 69f900d289b2..ff5596dd30f8 100644
--- a/include/linux/fbcon.h
+++ b/include/linux/fbcon.h
@@ -17,6 +17,8 @@ void fbcon_get_requirement(struct fb_info *info,
void fbcon_fb_blanked(struct fb_info *info, int blank);
void fbcon_update_vcs(struct fb_info *info, bool all);
void fbcon_remap_all(struct fb_info *info);
+int fbcon_set_con2fb_map_ioctl(void __user *argp);
+int fbcon_get_con2fb_map_ioctl(void __user *argp);
#else
static inline void fb_console_init(void) {}
static inline void fb_console_exit(void) {}
@@ -33,6 +35,8 @@ static inline void fbcon_get_requirement(struct fb_info *info,
static inline void fbcon_fb_blanked(struct fb_info *info, int blank) {}
static inline void fbcon_update_vcs(struct fb_info *info, bool all) {}
static inline void fbcon_remap_all(struct fb_info *info) {}
+static inline int fbcon_set_con2fb_map_ioctl(void __user *argp) { return 0; }
+static inline int fbcon_get_con2fb_map_ioctl(void __user *argp) { return 0; }
#endif

#endif /* _LINUX_FBCON_H */
--
2.20.1