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video/aperture: optionally match the device in sysfb_disable()

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In aperture_remove_conflicting_pci_devices(), we currently only
call sysfb_disable() on vga class devices.  This leads to the
following problem when the pimary device is not VGA compatible:

1. A PCI device with a non-VGA class is the boot display
2. That device is probed first and it is not a VGA device so
   sysfb_disable() is not called, but the device resources
   are freed by aperture_detach_platform_device()
3. Non-primary GPU has a VGA class and it ends up calling sysfb_disable()
4. NULL pointer dereference via sysfb_disable() since the resources
   have already been freed by aperture_detach_platform_device() when
   it was called by the other device.

Fix this by passing a device pointer to sysfb_disable() and checking
the device to determine if we should execute it or not.

v2: Fix build when CONFIG_SCREEN_INFO is not set
v3: Move device check into the mutex
    Drop primary variable in aperture_remove_conflicting_pci_devices()
    Drop __init on pci sysfb_pci_dev_is_enabled()

Fixes: 5ae3716cfd ("video/aperture: Only remove sysfb on the default vga pci device")
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Helge Deller <deller@gmx.de>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240821191135.829765-1-alexander.deucher@amd.com
This commit is contained in:
Alex Deucher 2024-08-21 15:11:35 -04:00
parent e9fd436bb8
commit b49420d6a1
4 changed files with 19 additions and 17 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

19
drivers/firmware/sysfb.c
View file

@ -39,6 +39,8 @@ static struct platform_device *pd;
static DEFINE_MUTEX(disable_lock);
static bool disabled;
static struct device *sysfb_parent_dev(const struct screen_info *si);
static bool sysfb_unregister(void)
{
if (IS_ERR_OR_NULL(pd))
@ -52,6 +54,7 @@ static bool sysfb_unregister(void)
/**
* sysfb_disable() - disable the Generic System Framebuffers support
* @dev: the device to check if non-NULL
*
* This disables the registration of system framebuffer devices that match the
* generic drivers that make use of the system framebuffer set up by firmware.
@ -61,17 +64,21 @@ static bool sysfb_unregister(void)
* Context: The function can sleep. A @disable_lock mutex is acquired to serialize
* against sysfb_init(), that registers a system framebuffer device.
*/
void sysfb_disable(void)
void sysfb_disable(struct device *dev)
{
struct screen_info *si = &screen_info;
mutex_lock(&disable_lock);
sysfb_unregister();
disabled = true;
if (!dev || dev == sysfb_parent_dev(si)) {
sysfb_unregister();
disabled = true;
}
mutex_unlock(&disable_lock);
}
EXPORT_SYMBOL_GPL(sysfb_disable);
#if defined(CONFIG_PCI)
static __init bool sysfb_pci_dev_is_enabled(struct pci_dev *pdev)
static bool sysfb_pci_dev_is_enabled(struct pci_dev *pdev)
{
/*
* TODO: Try to integrate this code into the PCI subsystem
@ -87,13 +94,13 @@ static __init bool sysfb_pci_dev_is_enabled(struct pci_dev *pdev)
return true;
}
#else
static __init bool sysfb_pci_dev_is_enabled(struct pci_dev *pdev)
static bool sysfb_pci_dev_is_enabled(struct pci_dev *pdev)
{
return false;
}
#endif
static __init struct device *sysfb_parent_dev(const struct screen_info *si)
static struct device *sysfb_parent_dev(const struct screen_info *si)
{
struct pci_dev *pdev;

2
drivers/of/platform.c
View file

@ -592,7 +592,7 @@ static int __init of_platform_default_populate_init(void)
* This can happen for example on DT systems that do EFI
* booting and may provide a GOP handle to the EFI stub.
*/
sysfb_disable();
sysfb_disable(NULL);
of_platform_device_create(node, NULL, NULL);
of_node_put(node);
}

11
drivers/video/aperture.c
View file

@ -293,7 +293,7 @@ int aperture_remove_conflicting_devices(resource_size_t base, resource_size_t si
* ask for this, so let's assume that a real driver for the display
* was already probed and prevent sysfb to register devices later.
*/
sysfb_disable();
sysfb_disable(NULL);
aperture_detach_devices(base, size);
@ -346,15 +346,10 @@ EXPORT_SYMBOL(__aperture_remove_legacy_vga_devices);
*/
int aperture_remove_conflicting_pci_devices(struct pci_dev *pdev, const char *name)
{
bool primary = false;
resource_size_t base, size;
int bar, ret = 0;
if (pdev == vga_default_device())
primary = true;
if (primary)
sysfb_disable();
sysfb_disable(&pdev->dev);
for (bar = 0; bar < PCI_STD_NUM_BARS; ++bar) {
if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM))
@ -370,7 +365,7 @@ int aperture_remove_conflicting_pci_devices(struct pci_dev *pdev, const char *na
* that consumes the VGA framebuffer I/O range. Remove this
* device as well.
*/
if (primary)
if (pdev == vga_default_device())
ret = __aperture_remove_legacy_vga_devices(pdev);
return ret;

4
include/linux/sysfb.h
View file

@ -58,11 +58,11 @@ struct efifb_dmi_info {
#ifdef CONFIG_SYSFB
void sysfb_disable(void);
void sysfb_disable(struct device *dev);
#else /* CONFIG_SYSFB */
static inline void sysfb_disable(void)
static inline void sysfb_disable(struct device *dev)
{
}