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>
---
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
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