firmware/sysfb: Update screen_info for relocated EFI framebuffers

[ Upstream commit 78aa89d1dfba1e3cf4a2e053afa3b4c4ec622371 ]

On ARM PCI systems, the PCI hierarchy might be reconfigured during
boot and the firmware framebuffer might move as a result of that.
The values in screen_info will then be invalid.

Work around this problem by tracking the framebuffer's initial
location before it get relocated; then fix the screen_info state
between reloaction and creating the firmware framebuffer's device.

This functionality has been lifted from efifb. See the commit message
of commit 55d728a40d ("efi/fb: Avoid reconfiguration of BAR that
covers the framebuffer") for more information.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240212090736.11464-8-tzimmermann@suse.de
Stable-dep-of: c2bc958b2b03 ("fbdev: vesafb: Detect VGA compatibility from screen info's VESA attributes")
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Thomas Zimmermann 2024-02-12 10:06:15 +01:00 committed by Greg Kroah-Hartman
parent f5dce77f3f
commit a168da3182
3 changed files with 106 additions and 0 deletions

View File

@ -77,6 +77,8 @@ static __init int sysfb_init(void)
bool compatible;
int ret = 0;
screen_info_apply_fixups();
mutex_lock(&disable_lock);
if (disabled)
goto unlock_mutex;

View File

@ -1,7 +1,95 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/pci.h>
#include <linux/printk.h>
#include <linux/screen_info.h>
#include <linux/string.h>
static struct pci_dev *screen_info_lfb_pdev;
static size_t screen_info_lfb_bar;
static resource_size_t screen_info_lfb_offset;
static struct resource screen_info_lfb_res = DEFINE_RES_MEM(0, 0);
static bool __screen_info_relocation_is_valid(const struct screen_info *si, struct resource *pr)
{
u64 size = __screen_info_lfb_size(si, screen_info_video_type(si));
if (screen_info_lfb_offset > resource_size(pr))
return false;
if (size > resource_size(pr))
return false;
if (resource_size(pr) - size < screen_info_lfb_offset)
return false;
return true;
}
void screen_info_apply_fixups(void)
{
struct screen_info *si = &screen_info;
if (screen_info_lfb_pdev) {
struct resource *pr = &screen_info_lfb_pdev->resource[screen_info_lfb_bar];
if (pr->start != screen_info_lfb_res.start) {
if (__screen_info_relocation_is_valid(si, pr)) {
/*
* Only update base if we have an actual
* relocation to a valid I/O range.
*/
__screen_info_set_lfb_base(si, pr->start + screen_info_lfb_offset);
pr_info("Relocating firmware framebuffer to offset %pa[d] within %pr\n",
&screen_info_lfb_offset, pr);
} else {
pr_warn("Invalid relocating, disabling firmware framebuffer\n");
}
}
}
}
static void screen_info_fixup_lfb(struct pci_dev *pdev)
{
unsigned int type;
struct resource res[SCREEN_INFO_MAX_RESOURCES];
size_t i, numres;
int ret;
const struct screen_info *si = &screen_info;
if (screen_info_lfb_pdev)
return; // already found
type = screen_info_video_type(si);
if (type != VIDEO_TYPE_EFI)
return; // only applies to EFI
ret = screen_info_resources(si, res, ARRAY_SIZE(res));
if (ret < 0)
return;
numres = ret;
for (i = 0; i < numres; ++i) {
struct resource *r = &res[i];
const struct resource *pr;
if (!(r->flags & IORESOURCE_MEM))
continue;
pr = pci_find_resource(pdev, r);
if (!pr)
continue;
/*
* We've found a PCI device with the framebuffer
* resource. Store away the parameters to track
* relocation of the framebuffer aperture.
*/
screen_info_lfb_pdev = pdev;
screen_info_lfb_bar = pr - pdev->resource;
screen_info_lfb_offset = r->start - pr->start;
memcpy(&screen_info_lfb_res, r, sizeof(screen_info_lfb_res));
}
}
DECLARE_PCI_FIXUP_CLASS_HEADER(PCI_ANY_ID, PCI_ANY_ID, PCI_BASE_CLASS_DISPLAY, 16,
screen_info_fixup_lfb);
static struct pci_dev *__screen_info_pci_dev(struct resource *res)
{

View File

@ -4,6 +4,8 @@
#include <uapi/linux/screen_info.h>
#include <linux/bits.h>
/**
* SCREEN_INFO_MAX_RESOURCES - maximum number of resources per screen_info
*/
@ -27,6 +29,17 @@ static inline u64 __screen_info_lfb_base(const struct screen_info *si)
return lfb_base;
}
static inline void __screen_info_set_lfb_base(struct screen_info *si, u64 lfb_base)
{
si->lfb_base = lfb_base & GENMASK_ULL(31, 0);
si->ext_lfb_base = (lfb_base & GENMASK_ULL(63, 32)) >> 32;
if (si->ext_lfb_base)
si->capabilities |= VIDEO_CAPABILITY_64BIT_BASE;
else
si->capabilities &= ~VIDEO_CAPABILITY_64BIT_BASE;
}
static inline u64 __screen_info_lfb_size(const struct screen_info *si, unsigned int type)
{
u64 lfb_size = si->lfb_size;
@ -106,8 +119,11 @@ static inline unsigned int screen_info_video_type(const struct screen_info *si)
ssize_t screen_info_resources(const struct screen_info *si, struct resource *r, size_t num);
#if defined(CONFIG_PCI)
void screen_info_apply_fixups(void);
struct pci_dev *screen_info_pci_dev(const struct screen_info *si);
#else
static inline void screen_info_apply_fixups(void)
{ }
static inline struct pci_dev *screen_info_pci_dev(const struct screen_info *si)
{
return NULL;