From 04cfcc7ab358e331b32cabde1e853a125f3f8735 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Wed, 22 Aug 2018 10:54:02 +0200 Subject: fbdev: Drop FBINFO_CAN_FORCE_OUTPUT flag This was only added for the drm's fbdev emulation support, so that it would try harder to show the Oops. Unfortunately this never really worked reliably, and in practice ended up pushing the real Oops off the screen due to plentyfull locking, sleep-while-atomic and other issues. So we removed all that support from the fbdev emulation a while back. Aside: We've also removed the kgdb support, for similar reasons. Since it's such a small patch I figured I don't split this up into the usual 3-phase removal. Acked-by: Bartlomiej Zolnierkiewicz Cc: Ben Skeggs Cc: Bartlomiej Zolnierkiewicz Cc: Greg Kroah-Hartman Cc: Hans de Goede Cc: Daniel Vetter Cc: Alexander Kapshuk Cc: Kees Cook Cc: Thierry Reding Cc: David Lechner Cc: nouveau@lists.freedesktop.org Cc: linux-fbdev@vger.kernel.org Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20180822085405.10787-1-daniel.vetter@ffwll.ch --- include/linux/fb.h | 4 ---- 1 file changed, 4 deletions(-) (limited to 'include/linux') diff --git a/include/linux/fb.h b/include/linux/fb.h index 3cd375dafd0e..b1db5c5eb671 100644 --- a/include/linux/fb.h +++ b/include/linux/fb.h @@ -457,10 +457,6 @@ struct fb_tile_ops { */ #define FBINFO_BE_MATH 0x100000 -/* report to the VT layer that this fb driver can accept forced console - output like oopses */ -#define FBINFO_CAN_FORCE_OUTPUT 0x200000 - struct fb_info { atomic_t count; int node; -- cgit v1.2.3-71-gd317 From 8d7fc2994f4d1f431e280c9e21a139c18dc435ec Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Wed, 22 Aug 2018 10:54:03 +0200 Subject: vt: Remove vc_panic_force_write It was only used by the panic support in fbcon, which is now gone. Remove this now dead code too. Acked-by: Greg Kroah-Hartman Cc: Greg Kroah-Hartman Cc: Kees Cook Cc: Joe Perches Cc: Daniel Vetter Cc: Meng Xu Cc: Nicolas Pitre Cc: Thomas Meyer Cc: Mike Frysinger Cc: Bartlomiej Zolnierkiewicz Cc: Hans de Goede Cc: Thierry Reding Cc: David Lechner Cc: Philippe Ombredanne Cc: Thomas Gleixner Cc: Kate Stewart Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20180822085405.10787-2-daniel.vetter@ffwll.ch --- drivers/tty/vt/vt.c | 12 ++++-------- drivers/video/fbdev/core/fbcon.c | 3 +-- include/linux/console_struct.h | 1 - include/linux/vt_kern.h | 7 ------- 4 files changed, 5 insertions(+), 18 deletions(-) (limited to 'include/linux') diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c index 5f1183b0b89d..55370e651db3 100644 --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -1004,9 +1004,7 @@ void redraw_screen(struct vc_data *vc, int is_switch) clear_buffer_attributes(vc); } - /* Forcibly update if we're panicing */ - if ((update && vc->vc_mode != KD_GRAPHICS) || - vt_force_oops_output(vc)) + if (update && vc->vc_mode != KD_GRAPHICS) do_update_region(vc, vc->vc_origin, vc->vc_screenbuf_size / 2); } set_cursor(vc); @@ -1046,7 +1044,6 @@ static void visual_init(struct vc_data *vc, int num, int init) vc->vc_hi_font_mask = 0; vc->vc_complement_mask = 0; vc->vc_can_do_color = 0; - vc->vc_panic_force_write = false; vc->vc_cur_blink_ms = DEFAULT_CURSOR_BLINK_MS; vc->vc_sw->con_init(vc, init); if (!vc->vc_complement_mask) @@ -2911,7 +2908,7 @@ static void vt_console_print(struct console *co, const char *b, unsigned count) goto quit; } - if (vc->vc_mode != KD_TEXT && !vt_force_oops_output(vc)) + if (vc->vc_mode != KD_TEXT) goto quit; /* undraw cursor first */ @@ -4229,8 +4226,7 @@ void do_unblank_screen(int leaving_gfx) return; } vc = vc_cons[fg_console].d; - /* Try to unblank in oops case too */ - if (vc->vc_mode != KD_TEXT && !vt_force_oops_output(vc)) + if (vc->vc_mode != KD_TEXT) return; /* but leave console_blanked != 0 */ if (blankinterval) { @@ -4239,7 +4235,7 @@ void do_unblank_screen(int leaving_gfx) } console_blanked = 0; - if (vc->vc_sw->con_blank(vc, 0, leaving_gfx) || vt_force_oops_output(vc)) + if (vc->vc_sw->con_blank(vc, 0, leaving_gfx)) /* Low-level driver cannot restore -> do it ourselves */ update_screen(vc); if (console_blank_hook) diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c index 9fd99681a7f2..8958ccc8b1ac 100644 --- a/drivers/video/fbdev/core/fbcon.c +++ b/drivers/video/fbdev/core/fbcon.c @@ -284,8 +284,7 @@ static inline int fbcon_is_inactive(struct vc_data *vc, struct fb_info *info) struct fbcon_ops *ops = info->fbcon_par; return (info->state != FBINFO_STATE_RUNNING || - vc->vc_mode != KD_TEXT || ops->graphics) && - !vt_force_oops_output(vc); + vc->vc_mode != KD_TEXT || ops->graphics); } static int get_color(struct vc_data *vc, struct fb_info *info, diff --git a/include/linux/console_struct.h b/include/linux/console_struct.h index fea64f2692a0..ab137f97ecbd 100644 --- a/include/linux/console_struct.h +++ b/include/linux/console_struct.h @@ -141,7 +141,6 @@ struct vc_data { struct uni_pagedir *vc_uni_pagedir; struct uni_pagedir **vc_uni_pagedir_loc; /* [!] Location of uni_pagedir variable for this console */ struct uni_screen *vc_uni_screen; /* unicode screen content */ - bool vc_panic_force_write; /* when oops/panic this VC can accept forced output/blanking */ /* additional information is in vt_kern.h */ }; diff --git a/include/linux/vt_kern.h b/include/linux/vt_kern.h index 3fd07912909c..8dc77e40bc03 100644 --- a/include/linux/vt_kern.h +++ b/include/linux/vt_kern.h @@ -135,13 +135,6 @@ extern int do_unbind_con_driver(const struct consw *csw, int first, int last, int deflt); int vty_init(const struct file_operations *console_fops); -static inline bool vt_force_oops_output(struct vc_data *vc) -{ - if (oops_in_progress && vc->vc_panic_force_write && panic_timeout >= 0) - return true; - return false; -} - extern char vt_dont_switch; extern int default_utf8; extern int global_cursor_default; -- cgit v1.2.3-71-gd317 From da6c7707caf3736c1cf968606bd97c07e79625d4 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Wed, 22 Aug 2018 10:54:04 +0200 Subject: fbdev: Add FBINFO_HIDE_SMEM_START flag DRM drivers really, really, really don't want random userspace to share buffer behind it's back, bypassing the dma-buf buffer sharing machanism. For that reason we've ruthlessly rejected any IOCTL exposing the physical address of any graphics buffer. Unfortunately fbdev comes with that built-in. We could just set smem_start to 0, but that means we'd have to hand-roll our own fb_mmap implementation. For good reasons many drivers do that, but smem_start/length is still super convenient. Hence instead just stop the leak in the ioctl, to keep fb mmap working as-is. A second patch will set this flag for all drm drivers. Acked-by: Bartlomiej Zolnierkiewicz Cc: Bartlomiej Zolnierkiewicz Cc: Kees Cook Cc: Daniel Vetter Cc: linux-fbdev@vger.kernel.org Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20180822085405.10787-3-daniel.vetter@ffwll.ch --- drivers/video/fbdev/core/fbmem.c | 4 ++++ include/linux/fb.h | 7 +++++++ 2 files changed, 11 insertions(+) (limited to 'include/linux') diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c index 0da75c55660d..861bf8081619 100644 --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -1117,6 +1117,8 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd, if (!lock_fb_info(info)) return -ENODEV; fix = info->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; @@ -1327,6 +1329,8 @@ static int fb_get_fscreeninfo(struct fb_info *info, unsigned int cmd, if (!lock_fb_info(info)) return -ENODEV; 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)); } diff --git a/include/linux/fb.h b/include/linux/fb.h index b1db5c5eb671..a3cab6dc9b44 100644 --- a/include/linux/fb.h +++ b/include/linux/fb.h @@ -456,6 +456,13 @@ struct fb_tile_ops { * and host endianness. Drivers should not use this flag. */ #define FBINFO_BE_MATH 0x100000 +/* + * Hide smem_start in the FBIOGET_FSCREENINFO IOCTL. This is used by modern DRM + * drivers to stop userspace from trying to share buffers behind the kernel's + * back. Instead dma-buf based buffer sharing should be used. + */ +#define FBINFO_HIDE_SMEM_START 0x200000 + struct fb_info { atomic_t count; -- cgit v1.2.3-71-gd317