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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2017-04-04 16:27:44 +0100
committerIngo Molnar <mingo@kernel.org>2017-04-05 12:25:53 +0200
commit55d728a40d368ba80443be85c02e641fc9082a3f (patch)
treeddcd3b0411791c00e1eeb82ef4350eb5323a24e2 /drivers/video
parent540f4c0e894f7e46a66dfa424b16424cbdc12c38 (diff)
efi/fb: Avoid reconfiguration of BAR that covers the framebuffer
On UEFI systems, the PCI subsystem is enumerated by the firmware, and if a graphical framebuffer is exposed via a PCI device, its base address and size are exposed to the OS via the Graphics Output Protocol (GOP). On arm64 PCI systems, the entire PCI hierarchy is reconfigured from scratch at boot. This may result in the GOP framebuffer address to become stale, if the BAR covering the framebuffer is modified. This will cause the framebuffer to become unresponsive, and may in some cases result in unpredictable behavior if the range is reassigned to another device. So add a non-x86 quirk to the EFI fb driver to find the BAR associated with the GOP base address, and claim the BAR resource so that the PCI core will not move it. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: <stable@vger.kernel.org> # v4.7+ Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Peter Jones <pjones@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: leif.lindholm@linaro.org Cc: linux-efi@vger.kernel.org Cc: lorenzo.pieralisi@arm.com Fixes: 9822504c1fa5 ("efifb: Enable the efi-framebuffer platform driver ...") Link: http://lkml.kernel.org/r/20170404152744.26687-3-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/video')
-rw-r--r--drivers/video/fbdev/efifb.c66
1 files changed, 65 insertions, 1 deletions
diff --git a/drivers/video/fbdev/efifb.c b/drivers/video/fbdev/efifb.c
index 8c4dc1e1f94f..b827a8113e26 100644
--- a/drivers/video/fbdev/efifb.c
+++ b/drivers/video/fbdev/efifb.c
@@ -10,6 +10,7 @@
#include <linux/efi.h>
#include <linux/errno.h>
#include <linux/fb.h>
+#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/screen_info.h>
#include <video/vga.h>
@@ -143,6 +144,8 @@ static struct attribute *efifb_attrs[] = {
};
ATTRIBUTE_GROUPS(efifb);
+static bool pci_dev_disabled; /* FB base matches BAR of a disabled device */
+
static int efifb_probe(struct platform_device *dev)
{
struct fb_info *info;
@@ -152,7 +155,7 @@ static int efifb_probe(struct platform_device *dev)
unsigned int size_total;
char *option = NULL;
- if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI)
+ if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI || pci_dev_disabled)
return -ENODEV;
if (fb_get_options("efifb", &option))
@@ -360,3 +363,64 @@ static struct platform_driver efifb_driver = {
};
builtin_platform_driver(efifb_driver);
+
+#if defined(CONFIG_PCI) && !defined(CONFIG_X86)
+
+static bool pci_bar_found; /* did we find a BAR matching the efifb base? */
+
+static void claim_efifb_bar(struct pci_dev *dev, int idx)
+{
+ u16 word;
+
+ pci_bar_found = true;
+
+ pci_read_config_word(dev, PCI_COMMAND, &word);
+ if (!(word & PCI_COMMAND_MEMORY)) {
+ pci_dev_disabled = true;
+ dev_err(&dev->dev,
+ "BAR %d: assigned to efifb but device is disabled!\n",
+ idx);
+ return;
+ }
+
+ if (pci_claim_resource(dev, idx)) {
+ pci_dev_disabled = true;
+ dev_err(&dev->dev,
+ "BAR %d: failed to claim resource for efifb!\n", idx);
+ return;
+ }
+
+ dev_info(&dev->dev, "BAR %d: assigned to efifb\n", idx);
+}
+
+static void efifb_fixup_resources(struct pci_dev *dev)
+{
+ u64 base = screen_info.lfb_base;
+ u64 size = screen_info.lfb_size;
+ int i;
+
+ if (pci_bar_found || screen_info.orig_video_isVGA != VIDEO_TYPE_EFI)
+ return;
+
+ if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE)
+ base |= (u64)screen_info.ext_lfb_base << 32;
+
+ if (!base)
+ return;
+
+ for (i = 0; i < PCI_STD_RESOURCE_END; i++) {
+ struct resource *res = &dev->resource[i];
+
+ if (!(res->flags & IORESOURCE_MEM))
+ continue;
+
+ if (res->start <= base && res->end >= base + size - 1) {
+ claim_efifb_bar(dev, i);
+ break;
+ }
+ }
+}
+DECLARE_PCI_FIXUP_CLASS_HEADER(PCI_ANY_ID, PCI_ANY_ID, PCI_BASE_CLASS_DISPLAY,
+ 16, efifb_fixup_resources);
+
+#endif