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Commit f96acec8 authored by David Herrmann's avatar David Herrmann Committed by Ingo Molnar
Browse files

x86/sysfb: Fix lfb_size calculation 



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: default avatarDavid Herrmann <dh.herrmann@gmail.com>
Acked-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tom Gundersen <teg@jklm.no>
Link: http://lkml.kernel.org/r/20161115120158.15388-3-dh.herrmann@gmail.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 9164b4ce

arch/x86/kernel/sysfb_simplefb.c

+17 −8
Original line number Diff line number Diff line
@@ -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;