// SPDX-License-Identifier: GPL-2.0
#include <linux/compat.h>
#include <linux/console.h>
#include <linux/fb.h>
#include <linux/fbcon.h>
#include <linux/major.h>
#include "fb_internal.h"
/*
* We hold a reference to the fb_info in file->private_data,
* but if the current registered fb has changed, we don't
* actually want to use it.
*
* So look up the fb_info using the inode minor number,
* and just verify it against the reference we have.
*/
static struct fb_info *file_fb_info(struct file *file)
{
struct inode *inode = file_inode(file);
int fbidx = iminor(inode);
struct fb_info *info = registered_fb[fbidx];
if (info != file->private_data)
info = NULL;
return info;
}
static ssize_t fb_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
struct fb_info *info = file_fb_info(file);
if (!info)
return -ENODEV;
if (fb_WARN_ON_ONCE(info, !info->fbops->fb_read))
return -EINVAL;
if (info->state != FBINFO_STATE_RUNNING)
return -EPERM;
return info->fbops->fb_read(info, buf, count, ppos);
}
static ssize_t fb_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
{
struct fb_info *info = file_fb_info(file);
if (!info)
return -ENODEV;
if (fb_WARN_ON_ONCE(info, !info->fbops->fb_write))
return -EINVAL;
if (info->state != FBINFO_STATE_RUNNING)
return -EPERM;
return info->fbops->fb_write(info, buf, count, ppos);
}
static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
unsigned long arg)
{
const struct fb_ops *fb;
struct fb_var_screeninfo var;
struct fb_fix_screeninfo fix;
struct fb_cmap cmap_from;
struct fb_cmap_user cmap;
void __user *argp = (void __user *)arg;
long ret = 0;
switch (cmd) {
case FBIOGET_VSCREENINFO:
lock_fb_info(info);
var = info->var;
unlock_fb_info(info);
ret = copy_to_user(argp, &var, sizeof(var)) ? -EFAULT : 0;
break;
case FBIOPUT_VSCREENINFO:
if (copy_from_user(&var, argp, sizeof(var)))
return -EFAULT;
/* only for kernel-internal use */
var.activate &= ~FB_ACTIVATE_KD_TEXT;
console_lock();
lock_fb_info(info);
ret = fbcon_modechange_possible(info, &var);
if (!ret)
ret = fb_set_var(info, &var);
if (!ret)
fbcon_update_vcs(info, var.activate & FB_ACTIVATE_ALL);
unlock_fb_info(info);
console_unlock();
if (!ret && copy_to_user(argp, &var, sizeof(var)))
ret = -EFAULT;
break;
case FBIOGET_FSCREENINFO:
lock_fb_info(info);
memcpy(&fix, &info->fix, sizeof(fix));
if (info->flags & FBINFO_HIDE_SMEM_START)
fix.smem_start = 0;
unlock_fb_info(info);
ret = copy_to_user(argp, &fix, sizeof(fix)) ? -EFAULT : 0;
break;
case FBIOPUTCMAP:
if (copy_from_user(&cmap, argp, sizeof(cmap)))
return -EFAULT;
ret = fb_set_user_cmap(&cmap, info);
break;
case FBIOGETCMAP:
if (copy_from_user(&cmap, argp, sizeof(cmap)))
return -EFAULT;
lock_fb_info(info);
cmap_from = info->cmap;
unlock_fb_info(info);
ret = fb_cmap_to_user(&cmap_from, &cmap);
break;
case FBIOPAN_DISPLAY:
if (copy_from_user(&var, argp, sizeof(var)))
return -EFAULT;
console_lock();
lock_fb_info(info);
ret = fb_pan_display(info, &var);
unlock_fb_info(info);
console_unlock();
if (ret == 0 && copy_to_user(argp, &var, sizeof(var)))
return -EFAULT;
break;
case FBIO_CURSOR:
ret = -EINVAL;
break;
case FBIOGET_CON2FBMAP:
ret = fbcon_get_con2fb_map_ioctl(argp);
break;
case FBIOPUT_CON2FBMAP:
ret = fbcon_set_con2fb_map_ioctl(argp);
break;
case FBIOBLANK:
if (arg > FB_BLANK_POWERDOWN)
return -EINVAL;
console_lock();
lock_fb_info(info);
ret = fb_blank(info, arg);
/* might again call into fb_blank */
fbcon_fb_blanked(info, arg);
unlock_fb_info(info);
console_unlock();
break;
default:
lock_fb_info(info);
fb = info->fbops;
if (fb->fb_ioctl)
ret = fb->fb_ioctl(info, cmd, arg);
else
ret = -ENOTTY;
unlock_fb_info(info);
}
return ret;
}
static long fb_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
struct fb_info *info = file_fb_info(file);
if (!info)
return -ENODEV;
return do_fb_ioctl(info, cmd, arg);
}
#ifdef CONFIG_COMPAT
struct fb_fix_screeninfo32 {
char id[16];
compat_caddr_t smem_start;
u32 smem_len;
u32 type;
u32 type_aux;
u32 visual;
u16 xpanstep;
u16 ypanstep;
u16 ywrapstep;
u32 line_length;
compat_caddr_t mmio_start;
u32 mmio_len;
u32 accel;
u16 reserved[3];
};
struct fb_cmap32 {
u32 start;
u32 len;
compat_caddr_t red;
compat_caddr_t green;
compat_caddr_t blue;
compat_caddr_t transp;
};
static int fb_getput_cmap(struct fb_info *info, unsigned int cmd,
unsigned long arg)
{
struct fb_cmap32 cmap32;
struct fb_cmap cmap_from;
struct fb_cmap_user cmap;
if (copy_from_user(&cmap32, compat_ptr(arg), sizeof(cmap32)))
return -EFAULT;
cmap = (struct fb_cmap_user) {
.start = cmap32.start,
.len = cmap32.len,
.red = compat_ptr(cmap32.red),
.green = compat_ptr(cmap32.green),
.blue = compat_ptr(cmap32.blue),
.transp = compat_ptr(cmap32.transp),
};
if (cmd == FBIOPUTCMAP)
return fb_set_user_cmap(&cmap, info);
lock_fb_info(info);
cmap_from = info->cmap;
unlock_fb_info(info);
return fb_cmap_to_user(&cmap_from, &cmap);
}
static int do_fscreeninfo_to_user(struct fb_fix_screeninfo *fix,
struct fb_fix_screeninfo32 __user *fix32)
{
__u32 data;
int err;
err = copy_to_user(&fix32->id, &fix->id, sizeof(fix32->id));
data = (__u32) (unsigned long) fix->smem_start;
err |= put_user(data, &fix32->smem_start);
err |= put_user(fix->smem_len, &fix32->smem_len);
err |= put_user(fix->type, &fix32->type);
err |= put_user(fix->type_aux, &fix32->type_aux);
err |= put_user(fix->visual, &fix32->visual);
err |= put_user(fix->xpanstep, &fix32->xpanstep);
err |= put_user(fix->ypanstep, &fix32->ypanstep);
err |= put_user(fix->ywrapstep, &fix32->ywrapstep);
err |= put_user(fix->line_length, &fix32->line_length);
data = (__u32) (unsigned long) fix->mmio_start;
err |= put_user(data, &fix32->mmio_start);
err |= put_user(fix->mmio_len, &fix32->mmio_len);
err |= put_user(fix->accel, &fix32->accel);
err |= copy_to_user(fix32->reserved, fix->reserved,
sizeof(fix->reserved));
if (err)
return -EFAULT;
return 0;
}
static int fb_get_fscreeninfo(struct fb_info *info, unsigned int cmd,
unsigned long arg)
{
struct fb_fix_screeninfo fix;
lock_fb_info(info);
fix = info->fix;
if (info->flags & FBINFO_HIDE_SMEM_START)
fix.smem_start = 0;
unlock_fb_info(info);
return do_fscreeninfo_to_user(&fix, compat_ptr(arg));
}
static long fb_compat_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
struct fb_info *info = file_fb_info(file);
const struct fb_ops *fb;
long ret = -ENOIOCTLCMD;
if (!info)
return -ENODEV;
fb = info->fbops;
switch (cmd) {
case FBIOGET_VSCREENINFO:
case FBIOPUT_VSCREENINFO:
case FBIOPAN_DISPLAY:
case FBIOGET_CON2FBMAP:
case FBIOPUT_CON2FBMAP:
arg = (unsigned long) compat_ptr(arg);
fallthrough;
case FBIOBLANK:
ret = do_fb_ioctl(info, cmd, arg);
break;
case FBIOGET_FSCREENINFO:
ret = fb_get_fscreeninfo(info, cmd, arg);
break;
case FBIOGETCMAP:
case FBIOPUTCMAP:
ret = fb_getput_cmap(info, cmd, arg);
break;
default:
if (fb->fb_compat_ioctl)
ret = fb->fb_compat_ioctl(info, cmd, arg);
break;
}
return ret;
}
#endif
static int fb_mmap(struct file *file, struct vm_area_struct *vma)
{
struct fb_info *info = file_fb_info(file);
int res;
if (!info)
return -ENODEV;
if (fb_WARN_ON_ONCE(info, !info->fbops->fb_mmap))
return -ENODEV;
mutex_lock(&info->mm_lock);
res = info->fbops->fb_mmap(info, vma);
mutex_unlock(&info->mm_lock);
return res;
}
static int fb_open(struct inode *inode, struct file *file)
__acquires(&info->lock)
__releases(&info->lock)
{
int fbidx = iminor(inode);
struct fb_info *info;
int res = 0;
info = get_fb_info(fbidx);
if (!info) {
request_module("fb%d", fbidx);
info = get_fb_info(fbidx);
if (!info)
return -ENODEV;
}
if (IS_ERR(info))
return PTR_ERR(info);
lock_fb_info(info);
if (!try_module_get(info->fbops->owner)) {
res = -ENODEV;
goto out;
}
file->private_data = info;
if (info->fbops->fb_open) {
res = info->fbops->fb_open(info, 1);
if (res)
module_put(info->fbops->owner);
}
#ifdef CONFIG_FB_DEFERRED_IO
if (info->fbdefio)
fb_deferred_io_open(info, inode, file);
#endif
out:
unlock_fb_info(info);
if (res)
put_fb_info(info);
return res;
}
static int fb_release(struct inode *inode, struct file *file)
__acquires(&info->lock)
__releases(&info->lock)
{
struct fb_info * const info = file->private_data;
lock_fb_info(info);
#if IS_ENABLED(CONFIG_FB_DEFERRED_IO)
if (info->fbdefio)
fb_deferred_io_release(info);
#endif
if (info->fbops->fb_release)
info->fbops->fb_release(info, 1);
module_put(info->fbops->owner);
unlock_fb_info(info);
put_fb_info(info);
return 0;
}
#if defined(CONFIG_FB_PROVIDE_GET_FB_UNMAPPED_AREA) && !defined(CONFIG_MMU)
static unsigned long get_fb_unmapped_area(struct file *filp,
unsigned long addr, unsigned long len,
unsigned long pgoff, unsigned long flags)
{
struct fb_info * const info = filp->private_data;
unsigned long fb_size = PAGE_ALIGN(info->fix.smem_len);
if (pgoff > fb_size || len > fb_size - pgoff)
return -EINVAL;
return (unsigned long)info->screen_base + pgoff;
}
#endif
static const struct file_operations fb_fops = {
.owner = THIS_MODULE,
.read = fb_read,
.write = fb_write,
.unlocked_ioctl = fb_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = fb_compat_ioctl,
#endif
.mmap = fb_mmap,
.open = fb_open,
.release = fb_release,
#if defined(HAVE_ARCH_FB_UNMAPPED_AREA) || \
(defined(CONFIG_FB_PROVIDE_GET_FB_UNMAPPED_AREA) && \
!defined(CONFIG_MMU))
.get_unmapped_area = get_fb_unmapped_area,
#endif
#ifdef CONFIG_FB_DEFERRED_IO
.fsync = fb_deferred_io_fsync,
#endif
.llseek = default_llseek,
};
int fb_register_chrdev(void)
{
int ret;
ret = register_chrdev(FB_MAJOR, "fb", &fb_fops);
if (ret) {
pr_err("Unable to get major %d for fb devs\n", FB_MAJOR);
return ret;
}
return ret;
}
void fb_unregister_chrdev(void)
{
unregister_chrdev(FB_MAJOR, "fb");
}
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