Apply PCI host-bridge window offsets to screen_info framebuffers. Fixes invalid access to I/O memory.
Resources behind a PCI host bridge can be relocated by a certain offset in the kernel's CPU address range used for I/O. The framebuffer memory range stored in screen_info refers to the CPU addresses as seen during boot (where the offset is 0). During boot up, firmware may assign a different memory offset to the PCI host bridge and thereby relocating the framebuffer address of the PCI graphics device as seen by the kernel. The information in screen_info must be updated as well.
The helper pcibios_bus_to_resource() performs the relocation of the screen_info's framebuffer resource (given in PCI bus addresses). The result matches the I/O-memory resource of the PCI graphics device (given in CPU addresses). As before, we store away the information necessary to later update the information in screen_info itself.
Commit 78aa89d1dfba ("firmware/sysfb: Update screen_info for relocated EFI framebuffers") added the code for updating screen_info. It is based on similar functionality that pre-existed in efifb. Efifb uses a pointer to the PCI resource, while the newer code does a memcpy of the region. Hence efifb sees any updates to the PCI resource and avoids the issue.
v3: - Only use struct pci_bus_region for PCI bus addresses (Bjorn) - Clarify address semantics in commit messages and comments (Bjorn) v2: - Fixed tags (Takashi, Ivan) - Updated information on efifb
Signed-off-by: Thomas Zimmermann tzimmermann@suse.de Reviewed-by: Javier Martinez Canillas javierm@redhat.com Reported-by: "Ivan T. Ivanov" iivanov@suse.de Closes: https://bugzilla.suse.com/show_bug.cgi?id=1240696 Tested-by: "Ivan T. Ivanov" iivanov@suse.de Fixes: 78aa89d1dfba ("firmware/sysfb: Update screen_info for relocated EFI framebuffers") Cc: dri-devel@lists.freedesktop.org Cc: stable@vger.kernel.org # v6.9+ --- drivers/video/screen_info_pci.c | 79 +++++++++++++++++++++------------ 1 file changed, 50 insertions(+), 29 deletions(-)
diff --git a/drivers/video/screen_info_pci.c b/drivers/video/screen_info_pci.c index 6c5833517141..66bfc1d0a6dc 100644 --- a/drivers/video/screen_info_pci.c +++ b/drivers/video/screen_info_pci.c @@ -7,8 +7,8 @@
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 resource_size_t screen_info_lfb_res_start; // original start of resource +static resource_size_t screen_info_lfb_offset; // framebuffer offset within resource
static bool __screen_info_relocation_is_valid(const struct screen_info *si, struct resource *pr) { @@ -31,7 +31,7 @@ void screen_info_apply_fixups(void) 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 (pr->start != screen_info_lfb_res_start) { if (__screen_info_relocation_is_valid(si, pr)) { /* * Only update base if we have an actual @@ -47,46 +47,67 @@ void screen_info_apply_fixups(void) } }
+static int __screen_info_lfb_pci_bus_region(const struct screen_info *si, unsigned int type, + struct pci_bus_region *r) +{ + u64 base, size; + + base = __screen_info_lfb_base(si); + if (!base) + return -EINVAL; + + size = __screen_info_lfb_size(si, type); + if (!size) + return -EINVAL; + + r->start = base; + r->end = base + size - 1; + + return 0; +} + static void screen_info_fixup_lfb(struct pci_dev *pdev) { unsigned int type; - struct resource res[SCREEN_INFO_MAX_RESOURCES]; - size_t i, numres; + struct pci_bus_region bus_region; int ret; + struct resource r = { + .flags = IORESOURCE_MEM, + }; + const struct resource *pr; 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 + if (!__screen_info_has_lfb(type)) + return; // only applies to EFI; maybe VESA
- ret = screen_info_resources(si, res, ARRAY_SIZE(res)); + ret = __screen_info_lfb_pci_bus_region(si, type, &bus_region); 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)); - } + /* + * Translate the PCI bus address to resource. Account + * for an offset if the framebuffer is behind a PCI host + * bridge. + */ + pcibios_bus_to_resource(pdev->bus, &r, &bus_region); + + pr = pci_find_resource(pdev, &r); + if (!pr) + return; + + /* + * 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; + screen_info_lfb_res_start = bus_region.start; } DECLARE_PCI_FIXUP_CLASS_HEADER(PCI_ANY_ID, PCI_ANY_ID, PCI_BASE_CLASS_DISPLAY, 16, screen_info_fixup_lfb);
If there are no further comment, I'll merge this patch via drm-misc-fixes.
Am 28.05.25 um 10:02 schrieb Thomas Zimmermann:
Apply PCI host-bridge window offsets to screen_info framebuffers. Fixes invalid access to I/O memory.
Resources behind a PCI host bridge can be relocated by a certain offset in the kernel's CPU address range used for I/O. The framebuffer memory range stored in screen_info refers to the CPU addresses as seen during boot (where the offset is 0). During boot up, firmware may assign a different memory offset to the PCI host bridge and thereby relocating the framebuffer address of the PCI graphics device as seen by the kernel. The information in screen_info must be updated as well.
The helper pcibios_bus_to_resource() performs the relocation of the screen_info's framebuffer resource (given in PCI bus addresses). The result matches the I/O-memory resource of the PCI graphics device (given in CPU addresses). As before, we store away the information necessary to later update the information in screen_info itself.
Commit 78aa89d1dfba ("firmware/sysfb: Update screen_info for relocated EFI framebuffers") added the code for updating screen_info. It is based on similar functionality that pre-existed in efifb. Efifb uses a pointer to the PCI resource, while the newer code does a memcpy of the region. Hence efifb sees any updates to the PCI resource and avoids the issue.
v3:
- Only use struct pci_bus_region for PCI bus addresses (Bjorn)
- Clarify address semantics in commit messages and comments (Bjorn)
v2:
- Fixed tags (Takashi, Ivan)
- Updated information on efifb
Signed-off-by: Thomas Zimmermann tzimmermann@suse.de Reviewed-by: Javier Martinez Canillas javierm@redhat.com Reported-by: "Ivan T. Ivanov" iivanov@suse.de Closes: https://bugzilla.suse.com/show_bug.cgi?id=1240696 Tested-by: "Ivan T. Ivanov" iivanov@suse.de Fixes: 78aa89d1dfba ("firmware/sysfb: Update screen_info for relocated EFI framebuffers") Cc: dri-devel@lists.freedesktop.org Cc: stable@vger.kernel.org # v6.9+
drivers/video/screen_info_pci.c | 79 +++++++++++++++++++++------------ 1 file changed, 50 insertions(+), 29 deletions(-)
diff --git a/drivers/video/screen_info_pci.c b/drivers/video/screen_info_pci.c index 6c5833517141..66bfc1d0a6dc 100644 --- a/drivers/video/screen_info_pci.c +++ b/drivers/video/screen_info_pci.c @@ -7,8 +7,8 @@ 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 resource_size_t screen_info_lfb_res_start; // original start of resource +static resource_size_t screen_info_lfb_offset; // framebuffer offset within resource static bool __screen_info_relocation_is_valid(const struct screen_info *si, struct resource *pr) { @@ -31,7 +31,7 @@ void screen_info_apply_fixups(void) 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 (pr->start != screen_info_lfb_res_start) { if (__screen_info_relocation_is_valid(si, pr)) { /* * Only update base if we have an actual
@@ -47,46 +47,67 @@ void screen_info_apply_fixups(void) } } +static int __screen_info_lfb_pci_bus_region(const struct screen_info *si, unsigned int type,
struct pci_bus_region *r)
+{
- u64 base, size;
- base = __screen_info_lfb_base(si);
- if (!base)
return -EINVAL;
- size = __screen_info_lfb_size(si, type);
- if (!size)
return -EINVAL;
- r->start = base;
- r->end = base + size - 1;
- return 0;
+}
- static void screen_info_fixup_lfb(struct pci_dev *pdev) { unsigned int type;
- struct resource res[SCREEN_INFO_MAX_RESOURCES];
- size_t i, numres;
- struct pci_bus_region bus_region; int ret;
- struct resource r = {
.flags = IORESOURCE_MEM,
- };
- const struct resource *pr; 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
- if (!__screen_info_has_lfb(type))
return; // only applies to EFI; maybe VESA
- ret = screen_info_resources(si, res, ARRAY_SIZE(res));
- ret = __screen_info_lfb_pci_bus_region(si, type, &bus_region); 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));
- }
- /*
* Translate the PCI bus address to resource. Account
* for an offset if the framebuffer is behind a PCI host
* bridge.
*/
- pcibios_bus_to_resource(pdev->bus, &r, &bus_region);
- pr = pci_find_resource(pdev, &r);
- if (!pr)
return;
- /*
* 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;
- screen_info_lfb_res_start = bus_region.start; } DECLARE_PCI_FIXUP_CLASS_HEADER(PCI_ANY_ID, PCI_ANY_ID, PCI_BASE_CLASS_DISPLAY, 16, screen_info_fixup_lfb);
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