fbdev: sbuslib: remove compat_alloc_user_space usage

This is one of the last users of compat_alloc_user_space()
and copy_in_user(). The actual handler is implemented in the
same file and could be shared, but as I couldn't test this
properly I leave the native case alone and just make a straight
copy of it for the compat case, with a minimum set of
modifications.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200918100926.1447563-3-arnd@arndb.de

diff --git a/drivers/video/fbdev/sbuslib.c b/drivers/video/fbdev/sbuslib.c
index f728db9..7f79db8 100644 (file)
--- a/drivers/video/fbdev/sbuslib.c
+++ b/drivers/video/fbdev/sbuslib.c
@@ -192,28 +192,6 @@ int sbusfb_ioctl_helper(unsigned long cmd, unsigned long arg,
 EXPORT_SYMBOL(sbusfb_ioctl_helper);
 
 #ifdef CONFIG_COMPAT
-static int fbiogetputcmap(struct fb_info *info, unsigned int cmd, unsigned long arg)
-{
-       struct fbcmap32 __user *argp = (void __user *)arg;
-       struct fbcmap __user *p = compat_alloc_user_space(sizeof(*p));
-       u32 addr;
-       int ret;
-
-       ret = copy_in_user(p, argp, 2 * sizeof(int));
-       ret |= get_user(addr, &argp->red);
-       ret |= put_user(compat_ptr(addr), &p->red);
-       ret |= get_user(addr, &argp->green);
-       ret |= put_user(compat_ptr(addr), &p->green);
-       ret |= get_user(addr, &argp->blue);
-       ret |= put_user(compat_ptr(addr), &p->blue);
-       if (ret)
-               return -EFAULT;
-       return info->fbops->fb_ioctl(info,
-                       (cmd == FBIOPUTCMAP32) ?
-                       FBIOPUTCMAP_SPARC : FBIOGETCMAP_SPARC,
-                       (unsigned long)p);
-}
-
 int sbusfb_compat_ioctl(struct fb_info *info, unsigned int cmd, unsigned long arg)
 {
        switch (cmd) {
@@ -230,9 +208,76 @@ int sbusfb_compat_ioctl(struct fb_info *info, unsigned int cmd, unsigned long ar
        case FBIOGCURMAX:
                return info->fbops->fb_ioctl(info, cmd, arg);
        case FBIOPUTCMAP32:
-               return fbiogetputcmap(info, cmd, arg);
-       case FBIOGETCMAP32:
-               return fbiogetputcmap(info, cmd, arg);
+       case FBIOPUTCMAP_SPARC: {
+               struct fbcmap32 c;
+               struct fb_cmap cmap;
+               u16 red, green, blue;
+               u8 red8, green8, blue8;
+               unsigned char __user *ured;
+               unsigned char __user *ugreen;
+               unsigned char __user *ublue;
+               unsigned int i;
+
+               if (copy_from_user(&c, compat_ptr(arg), sizeof(c)))
+                       return -EFAULT;
+               ured = compat_ptr(c.red);
+               ugreen = compat_ptr(c.green);
+               ublue = compat_ptr(c.blue);
+
+               cmap.len = 1;
+               cmap.red = &red;
+               cmap.green = &green;
+               cmap.blue = &blue;
+               cmap.transp = NULL;
+               for (i = 0; i < c.count; i++) {
+                       int err;
+
+                       if (get_user(red8, &ured[i]) ||
+                           get_user(green8, &ugreen[i]) ||
+                           get_user(blue8, &ublue[i]))
+                               return -EFAULT;
+
+                       red = red8 << 8;
+                       green = green8 << 8;
+                       blue = blue8 << 8;
+
+                       cmap.start = c.index + i;
+                       err = fb_set_cmap(&cmap, info);
+                       if (err)
+                               return err;
+               }
+               return 0;
+       }
+       case FBIOGETCMAP32: {
+               struct fbcmap32 c;
+               unsigned char __user *ured;
+               unsigned char __user *ugreen;
+               unsigned char __user *ublue;
+               struct fb_cmap *cmap = &info->cmap;
+               unsigned int index, i;
+               u8 red, green, blue;
+
+               if (copy_from_user(&c, compat_ptr(arg), sizeof(c)))
+                       return -EFAULT;
+               index = c.index;
+               ured = compat_ptr(c.red);
+               ugreen = compat_ptr(c.green);
+               ublue = compat_ptr(c.blue);
+
+               if (index > cmap->len || c.count > cmap->len - index)
+                       return -EINVAL;
+
+               for (i = 0; i < c.count; i++) {
+                       red = cmap->red[index + i] >> 8;
+                       green = cmap->green[index + i] >> 8;
+                       blue = cmap->blue[index + i] >> 8;
+                       if (put_user(red, &ured[i]) ||
+                           put_user(green, &ugreen[i]) ||
+                           put_user(blue, &ublue[i]))
+                               return -EFAULT;
+               }
+               return 0;
+       }
        default:
                return -ENOIOCTLCMD;
        }