On Fri, Sep 2, 2016 at 10:22 AM, David Herrmann <dh.herrmann@xxxxxxxxx> wrote:
> The screen_info.lfb_size field is shifted by 16 bits *only* in case of
> VBE. This has historical reasons since VBE advertised it similarly.
> However, in case of EFI framebuffers, the size is no longer shifted. Fix
> the x86 simple-framebuffer setup code to use the correct size in the
> non-VBE case.
>
> While at it, avoid variable abbreviations and rename 'len' to 'length',
> and use the correct types matching the screen_info definition.
>
> Signed-off-by: David Herrmann <dh.herrmann@xxxxxxxxx>
Reviewed-by: Tom Gundersen <teg@xxxxxxx>
> ---
> arch/x86/kernel/sysfb_simplefb.c | 25 +++++++++++++++++--------
> 1 file changed, 17 insertions(+), 8 deletions(-)
>
> diff --git a/arch/x86/kernel/sysfb_simplefb.c b/arch/x86/kernel/sysfb_simplefb.c
> index 35b8641..85195d4 100644
> --- a/arch/x86/kernel/sysfb_simplefb.c
> +++ b/arch/x86/kernel/sysfb_simplefb.c
> @@ -66,8 +66,8 @@ __init int create_simplefb(const struct screen_info *si,
> {
> struct platform_device *pd;
> struct resource res;
> - unsigned long len;
> - u64 base;
> + u64 base, size;
> + u32 length;
>
> /*
> * If the 64BIT_BASE capability is set, ext_lfb_base will contain the
> @@ -82,11 +82,20 @@ __init int create_simplefb(const struct screen_info *si,
> 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 */
> - len = mode->height * mode->stride;
> - len = PAGE_ALIGN(len);
> - if (len > (u64)si->lfb_size << 16) {
> + /*
> + * Don't use lfb_size as IORESOURCE size, since it may contain the
> + * entire VMEM, and thus require huge mappings. Use just the part we
> + * need, that is, the part where the framebuffer is located. But verify
> + * that it does not exceed the advertised VMEM.
> + * Note that in case of VBE, the lfb_size is shifted by 16 bits for
> + * historical reasons.
> + */
> + size = si->lfb_size;
> + if (si->orig_video_isVGA == VIDEO_TYPE_VLFB)
> + size <<= 16;
> + length = mode->height * mode->stride;
> + length = PAGE_ALIGN(length);
> + if (length > size) {
> printk(KERN_WARNING "sysfb: VRAM smaller than advertised\n");
> return -EINVAL;
> }
> @@ -96,7 +105,7 @@ __init int create_simplefb(const struct screen_info *si,
> res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
> res.name = simplefb_resname;
> res.start = base;
> - res.end = res.start + len - 1;
> + res.end = res.start + length - 1;
> if (res.end <= res.start)
> return -EINVAL;
>
> --
> 2.9.3
>
> _______________________________________________
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> dri-devel@xxxxxxxxxxxxxxxxxxxxx
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
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