fbdev: Replace fb_pgprotect() with pgprot_framebuffer()

Rename the fbdev mmap helper fb_pgprotect() to pgprot_framebuffer().
The helper sets VMA page-access flags for framebuffers in device I/O
memory.

Also clean up the helper's parameters and return value. Instead of
the VMA instance, pass the individial parameters separately: existing
page-access flags, the VMAs start and end addresses and the offset
in the underlying device memory rsp file. Return the new page-access
flags. These changes align pgprot_framebuffer() with other pgprot_()
functions.

v4:
* fix commit message (Christophe)
v3:
* rename fb_pgprotect() to pgprot_framebuffer() (Arnd)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> # m68k
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230922080636.26762-3-tzimmermann@suse.de

x86/fbdev: Include asm/fb.h as needed

fb_is_primary_device() is defined as a global function on x86, unlike
the others that have an inline version. The file that defines is
however needs to include the declaration to avoid a warning:

arch/x86/video/fbdev.c:14:5: error: no previous prototype for 'fb_is_primary_device' [-Werror=missing-prototypes]

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Link: https://lore.kernel.org/all/20230516193549.544673-15-arnd%40kernel.org

fbdev: Include <linux/fb.h> instead of <asm/fb.h>

Replace include statements for <asm/fb.h> with <linux/fb.h>. Fixes
the coding style: if a header is available in asm/ and linux/, it
is preferable to include the header from linux/. This only affects
a few source files, most of which already include <linux/fb.h>.

Suggested-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Sui Jingfeng <suijingfeng@loongson.cn>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230512102444.5438-6-tzimmermann@suse.de

arch/x86: Include <asm/fb.h> in fbdev source file

Move the implementation of fb_pgprotect() to fbdev.c and include
<asm/fb.h>. Fixes the following warning:

../arch/x86/video/fbdev.c:14:5: warning: no previous prototype for 'fb_is_primary_device' [-Wmissing-prototypes]
14 | int fb_is_primary_device(struct fb_info *info)
| ^~~~~~~~~~~~~~~~~~~~

Just including <asm/fb.h> results in a number of built-in errors
about undefined function. Moving fb_pgprotect() to the source file
avoids the required include statements in the header. The function
is only called occasionally from fb_mmap(), [1] so having it as static
inline had no benefit.

While at it, fix the codying style in fbdev.c.

Link: https://elixir.bootlin.com/linux/v6.3-rc7/source/drivers/video/fbdev/core/fbmem.c#L1404 # 1
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230424084751.14641-1-tzimmermann@suse.de

fbdev: Simplify fb_is_primary_device for x86

vga_default_device really is supposed to cover all corners, at least
for x86. Additionally checking for rom shadowing should be redundant,
because the bios/fw only does that for the boot vga device.

If this turns out to be wrong, then most likely that's a special case
which should be added to the vgaarb code, not replicated all over.

Patch motived by changes to the aperture helpers, which also have this
open code in a bunch of places, and which are all removed in a
clean-up series. This function here is just for selecting the default
fbdev device for fbcon, but I figured for consistency it might be good
to throw this patch in on top.

Note that the shadow rom check predates vgaarb, which was only wired
up in commit 88674088d10c ("x86: Use vga_default_device() when
determining whether an fb is primary"). That patch doesn't explain why
we still fall back to the shadow rom check.

v4:
- fix commit message style (i.e., commit 1234 ("..."))
- fix Daniel's S-o-b address

v5:
- add back an S-o-b tag with Daniel's Intel address

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Helge Deller <deller@gmx.de>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230406132109.32050-9-tzimmermann@suse.de

x86/video: Don't assume all FB devices are PCI devices

When booting Hyper-V Generation 2 guests KASAN reports the following
out-of-bounds access:

BUG: KASAN: slab-out-of-bounds in fb_is_primary_device+0x58/0x70 at addr ffff880079cf0eb0
Read of size 8 by task swapper/0/1
...
[<ffffffff81581308>] dump_stack+0x63/0x8b
[<ffffffff812e1f99>] print_trailer+0xf9/0x150
[<ffffffff812e7344>] object_err+0x34/0x40
[<ffffffff812e9630>] kasan_report_error+0x230/0x550
[<ffffffff812e9ee8>] kasan_report+0x58/0x60
[<ffffffff812e4500>] ? ___slab_alloc+0x80/0x490
[<ffffffff81878a28>] ? fb_is_primary_device+0x58/0x70
[<ffffffff812e87cd>] __asan_load8+0x5d/0x70
[<ffffffff81878a28>] fb_is_primary_device+0x58/0x70
[<ffffffff8162357a>] register_framebuffer+0xda/0x5b0
[<ffffffff816234a0>] ? remove_conflicting_framebuffers+0x50/0x50
...

The issue is caused by the to_pci_dev() call with no check that the given
info->device is in fact a PCI device and some FB devices (Hyper-V FB, EFI
FB,...) are not.

While on it, clean up the function.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Bjorn Helgaas <helgaas@kernel.org>
Cc: Cathy Avery <cavery@redhat.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1458030033-10122-1-git-send-email-vkuznets@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86: Use vga_default_device() when determining whether an fb is primary

IORESOURCE_ROM_SHADOW is not necessarily an indication that the hardware
is the primary device. Add support for using the vgaarb functions and
fall back if nothing's set them.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: mingo@redhat.com
Acked-by: hpa@zytor.com
Signed-off-by: Dave Airlie <airlied@redhat.com>

x86: fix up files really needing to include module.h

These files aren't just exporting symbols -- they are also defining
a MODULE_LICENSE etc. so give them the full module.h file.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

x86: video/fbdev.c: add MODULE_LICENSE

Add the missing MODULE_LICENSE("GPL").

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: remove pointless comments

Remove old comments that include the old arch/i386 directory.

Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

i386: move video

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>