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dacc909233
When checking whether the reported lfb_size makes sense, the height * stride result is page-aligned before seeing whether it exceeds the reported size. This doesn't work if height * stride is not an exact number of pages. For example, as reported in the kernel bugzilla below, an 800x600x32 EFI framebuffer gets skipped because of this. Move the PAGE_ALIGN to after the check vs size. Reported-by: Christopher Head <chead@chead.ca> Tested-by: Christopher Head <chead@chead.ca> Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://bugzilla.kernel.org/show_bug.cgi?id=206051 Link: https://lkml.kernel.org/r/20200107230410.2291947-1-nivedita@alum.mit.edu
112 lines
3.2 KiB
C
112 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Generic System Framebuffers on x86
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* Copyright (c) 2012-2013 David Herrmann <dh.herrmann@gmail.com>
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*/
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/*
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* simple-framebuffer probing
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* Try to convert "screen_info" into a "simple-framebuffer" compatible mode.
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* If the mode is incompatible, we return "false" and let the caller create
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* legacy nodes instead.
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*/
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/platform_data/simplefb.h>
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#include <linux/platform_device.h>
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#include <linux/screen_info.h>
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#include <asm/sysfb.h>
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static const char simplefb_resname[] = "BOOTFB";
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static const struct simplefb_format formats[] = SIMPLEFB_FORMATS;
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/* try parsing x86 screen_info into a simple-framebuffer mode struct */
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__init bool parse_mode(const struct screen_info *si,
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struct simplefb_platform_data *mode)
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{
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const struct simplefb_format *f;
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__u8 type;
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unsigned int i;
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type = si->orig_video_isVGA;
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if (type != VIDEO_TYPE_VLFB && type != VIDEO_TYPE_EFI)
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return false;
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for (i = 0; i < ARRAY_SIZE(formats); ++i) {
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f = &formats[i];
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if (si->lfb_depth == f->bits_per_pixel &&
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si->red_size == f->red.length &&
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si->red_pos == f->red.offset &&
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si->green_size == f->green.length &&
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si->green_pos == f->green.offset &&
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si->blue_size == f->blue.length &&
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si->blue_pos == f->blue.offset &&
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si->rsvd_size == f->transp.length &&
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si->rsvd_pos == f->transp.offset) {
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mode->format = f->name;
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mode->width = si->lfb_width;
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mode->height = si->lfb_height;
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mode->stride = si->lfb_linelength;
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return true;
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}
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}
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return false;
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}
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__init int create_simplefb(const struct screen_info *si,
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const struct simplefb_platform_data *mode)
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{
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struct platform_device *pd;
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struct resource res;
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u64 base, size;
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u32 length;
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/*
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* If the 64BIT_BASE capability is set, ext_lfb_base will contain the
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* upper half of the base address. Assemble the address, then make sure
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* it is valid and we can actually access it.
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*/
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base = si->lfb_base;
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if (si->capabilities & VIDEO_CAPABILITY_64BIT_BASE)
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base |= (u64)si->ext_lfb_base << 32;
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if (!base || (u64)(resource_size_t)base != base) {
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printk(KERN_DEBUG "sysfb: inaccessible VRAM base\n");
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return -EINVAL;
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}
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/*
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* Don't use lfb_size as IORESOURCE size, since it may contain the
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* entire VMEM, and thus require huge mappings. Use just the part we
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* need, that is, the part where the framebuffer is located. But verify
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* that it does not exceed the advertised VMEM.
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* Note that in case of VBE, the lfb_size is shifted by 16 bits for
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* historical reasons.
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*/
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size = si->lfb_size;
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if (si->orig_video_isVGA == VIDEO_TYPE_VLFB)
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size <<= 16;
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length = mode->height * mode->stride;
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if (length > size) {
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printk(KERN_WARNING "sysfb: VRAM smaller than advertised\n");
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return -EINVAL;
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}
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length = PAGE_ALIGN(length);
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/* setup IORESOURCE_MEM as framebuffer memory */
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memset(&res, 0, sizeof(res));
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res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
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res.name = simplefb_resname;
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res.start = base;
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res.end = res.start + length - 1;
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if (res.end <= res.start)
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return -EINVAL;
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pd = platform_device_register_resndata(NULL, "simple-framebuffer", 0,
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&res, 1, mode, sizeof(*mode));
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return PTR_ERR_OR_ZERO(pd);
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}
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