On Fri, Sep 2, 2016 at 10:22 AM, David Herrmann <dh.herrmann@xxxxxxxxx> wrote:
> The screen_info object was extended to support 64bit lfb_base addresses
> in:
>
> commit ae2ee627dc87a70910de91b791b3cd0e9c6facdd
> Author: Matt Fleming <matt.fleming@xxxxxxxxx>
> Date: Tue Aug 25 16:32:55 2015 +0100
>
> efifb: Add support for 64-bit frame buffer addresses
>
> However, the x86 simple-framebuffer setup code never made use of it. Fix
> it to properly assemble and verify the lfb_base before advertising
> simple-framebuffer devices.
>
> In particular, this means if VIDEO_CAPABILITY_64BIT_BASE is set, the
> screen_info->ext_lfb_base field will contain the upper 32bit of the
> actual lfb_base. Make sure the address is not 0 (i.e., unset), as well as
> does not overflow the physical address type.
>
> Signed-off-by: David Herrmann <dh.herrmann@xxxxxxxxx>
Reviewed-by: Tom Gundersen <teg@xxxxxxx>
> ---
> arch/x86/kernel/sysfb_simplefb.c | 18 ++++++++++++++++--
> 1 file changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kernel/sysfb_simplefb.c b/arch/x86/kernel/sysfb_simplefb.c
> index 764a29f..35b8641 100644
> --- a/arch/x86/kernel/sysfb_simplefb.c
> +++ b/arch/x86/kernel/sysfb_simplefb.c
> @@ -67,6 +67,20 @@ __init int create_simplefb(const struct screen_info *si,
> struct platform_device *pd;
> struct resource res;
> unsigned long len;
> + u64 base;
> +
> + /*
> + * If the 64BIT_BASE capability is set, ext_lfb_base will contain the
> + * upper half of the base address. Assemble the address, then make sure
> + * it is valid and we can actually access it.
> + */
> + base = si->lfb_base;
> + if (si->capabilities & VIDEO_CAPABILITY_64BIT_BASE)
> + base |= (u64)si->ext_lfb_base << 32;
> + if (!base || (u64)(resource_size_t)base != base) {
> + printk(KERN_DEBUG "sysfb: inaccessible VRAM base\n");
> + return -EINVAL;
> + }
>
> /* don't use lfb_size as it may contain the whole VMEM instead of only
> * the part that is occupied by the framebuffer */
> @@ -81,8 +95,8 @@ __init int create_simplefb(const struct screen_info *si,
> memset(&res, 0, sizeof(res));
> res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
> res.name = simplefb_resname;
> - res.start = si->lfb_base;
> - res.end = si->lfb_base + len - 1;
> + res.start = base;
> + res.end = res.start + len - 1;
> if (res.end <= res.start)
> return -EINVAL;
>
> --
> 2.9.3
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@xxxxxxxxxxxxxxxxxxxxx
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
_______________________________________________
dri-devel mailing list
dri-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/dri-devel
