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backport simplefb/fbdev memory regio release improvements

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Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
This commit is contained in:
Thomas Lamprecht 2022-02-08 11:42:02 +01:00
parent 525ea48834
commit 09d62646a4
4 changed files with 358 additions and 0 deletions
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117
patches/kernel/0010-fbdev-Hot-unplug-firmware-fb-devices-on-forced-remov.patch Normal file
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@ -0,0 +1,117 @@
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Thomas Zimmermann <tzimmermann@suse.de>
Date: Tue, 25 Jan 2022 10:12:18 +0100
Subject: [PATCH] fbdev: Hot-unplug firmware fb devices on forced removal
Hot-unplug all firmware-framebuffer devices as part of removing
them via remove_conflicting_framebuffers() et al. Releases all
memory regions to be acquired by native drivers.
Firmware, such as EFI, install a framebuffer while posting the
computer. After removing the firmware-framebuffer device from fbdev,
a native driver takes over the hardware and the firmware framebuffer
becomes invalid.
Firmware-framebuffer drivers, specifically simplefb, don't release
their device from Linux' device hierarchy. It still owns the firmware
framebuffer and blocks the native drivers from loading. This has been
observed in the vmwgfx driver. [1]
Initiating a device removal (i.e., hot unplug) as part of
remove_conflicting_framebuffers() removes the underlying device and
returns the memory range to the system.
[1] https://lore.kernel.org/dri-devel/20220117180359.18114-1-zack@kde.org/
v2:
* rename variable 'dev' to 'device' (Javier)
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reported-by: Zack Rusin <zackr@vmware.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Zack Rusin <zackr@vmware.com>
CC: stable@vger.kernel.org # v5.11+
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---
drivers/video/fbdev/core/fbmem.c | 29 ++++++++++++++++++++++++++---
include/linux/fb.h | 1 +
2 files changed, 27 insertions(+), 3 deletions(-)
diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index 7bd5e2a4a9da..91145d93990a 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -25,6 +25,7 @@
#include <linux/init.h>
#include <linux/linux_logo.h>
#include <linux/proc_fs.h>
+#include <linux/platform_device.h>
#include <linux/seq_file.h>
#include <linux/console.h>
#include <linux/kmod.h>
@@ -1557,18 +1558,36 @@ static void do_remove_conflicting_framebuffers(struct apertures_struct *a,
/* check all firmware fbs and kick off if the base addr overlaps */
for_each_registered_fb(i) {
struct apertures_struct *gen_aper;
+ struct device *device;
if (!(registered_fb[i]->flags & FBINFO_MISC_FIRMWARE))
continue;
gen_aper = registered_fb[i]->apertures;
+ device = registered_fb[i]->device;
if (fb_do_apertures_overlap(gen_aper, a) ||
(primary && gen_aper && gen_aper->count &&
gen_aper->ranges[0].base == VGA_FB_PHYS)) {
printk(KERN_INFO "fb%d: switching to %s from %s\n",
i, name, registered_fb[i]->fix.id);
- do_unregister_framebuffer(registered_fb[i]);
+
+ /*
+ * If we kick-out a firmware driver, we also want to remove
+ * the underlying platform device, such as simple-framebuffer,
+ * VESA, EFI, etc. A native driver will then be able to
+ * allocate the memory range.
+ *
+ * If it's not a platform device, at least print a warning. A
+ * fix would add code to remove the device from the system.
+ */
+ if (dev_is_platform(device)) {
+ registered_fb[i]->forced_out = true;
+ platform_device_unregister(to_platform_device(device));
+ } else {
+ pr_warn("fb%d: cannot remove device\n", i);
+ do_unregister_framebuffer(registered_fb[i]);
+ }
}
}
}
@@ -1895,9 +1914,13 @@ EXPORT_SYMBOL(register_framebuffer);
void
unregister_framebuffer(struct fb_info *fb_info)
{
- mutex_lock(&registration_lock);
+ bool forced_out = fb_info->forced_out;
+
+ if (!forced_out)
+ mutex_lock(&registration_lock);
do_unregister_framebuffer(fb_info);
- mutex_unlock(&registration_lock);
+ if (!forced_out)
+ mutex_unlock(&registration_lock);
}
EXPORT_SYMBOL(unregister_framebuffer);
diff --git a/include/linux/fb.h b/include/linux/fb.h
index 02f362c661c8..3d7306c9a706 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -502,6 +502,7 @@ struct fb_info {
} *apertures;
bool skip_vt_switch; /* no VT switch on suspend/resume required */
+ bool forced_out; /* set when being removed by another driver */
};
static inline struct apertures_struct *alloc_apertures(unsigned int max_num) {

34
patches/kernel/0011-drivers-firmware-Don-t-mark-as-busy-the-simple-frame.patch Normal file
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@ -0,0 +1,34 @@
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Javier Martinez Canillas <javierm@redhat.com>
Date: Tue, 25 Jan 2022 10:12:19 +0100
Subject: [PATCH] drivers/firmware: Don't mark as busy the simple-framebuffer
IO resource
The sysfb_create_simplefb() function requests a IO memory resource for the
simple-framebuffer platform device, but it also marks it as busy which can
lead to drivers requesting the same memory resource to fail.
Let's drop the IORESOURCE_BUSY flag and let drivers to request it as busy
instead.
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Zack Rusin <zackr@vmware.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---
drivers/firmware/sysfb_simplefb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/firmware/sysfb_simplefb.c b/drivers/firmware/sysfb_simplefb.c
index 303a491e520d..76c4abc42a30 100644
--- a/drivers/firmware/sysfb_simplefb.c
+++ b/drivers/firmware/sysfb_simplefb.c
@@ -99,7 +99,7 @@ __init int sysfb_create_simplefb(const struct screen_info *si,
/* setup IORESOURCE_MEM as framebuffer memory */
memset(&res, 0, sizeof(res));
- res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+ res.flags = IORESOURCE_MEM;
res.name = simplefb_resname;
res.start = base;
res.end = res.start + length - 1;

63
patches/kernel/0012-drm-simpledrm-Request-memory-region-in-driver.patch Normal file
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@ -0,0 +1,63 @@
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Thomas Zimmermann <tzimmermann@suse.de>
Date: Tue, 25 Jan 2022 10:12:20 +0100
Subject: [PATCH] drm/simpledrm: Request memory region in driver
Requesting the framebuffer memory in simpledrm marks the memory
range as busy. This used to be done by the firmware sysfb code,
but the driver is the correct place.
v2:
* use I/O memory if request_mem_region() fails (Jocelyn)
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---
drivers/gpu/drm/tiny/simpledrm.c | 22 +++++++++++++++++-----
1 file changed, 17 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/tiny/simpledrm.c b/drivers/gpu/drm/tiny/simpledrm.c
index 5a6e89825bc2..6da507960af6 100644
--- a/drivers/gpu/drm/tiny/simpledrm.c
+++ b/drivers/gpu/drm/tiny/simpledrm.c
@@ -525,21 +525,33 @@ static int simpledrm_device_init_mm(struct simpledrm_device *sdev)
{
struct drm_device *dev = &sdev->dev;
struct platform_device *pdev = sdev->pdev;
- struct resource *mem;
+ struct resource *res, *mem;
void __iomem *screen_base;
int ret;
- mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- if (!mem)
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
return -EINVAL;
- ret = devm_aperture_acquire_from_firmware(dev, mem->start, resource_size(mem));
+ ret = devm_aperture_acquire_from_firmware(dev, res->start, resource_size(res));
if (ret) {
drm_err(dev, "could not acquire memory range %pr: error %d\n",
- mem, ret);
+ res, ret);
return ret;
}
+ mem = devm_request_mem_region(&pdev->dev, res->start, resource_size(res),
+ sdev->dev.driver->name);
+ if (!mem) {
+ /*
+ * We cannot make this fatal. Sometimes this comes from magic
+ * spaces our resource handlers simply don't know about. Use
+ * the I/O-memory resource as-is and try to map that instead.
+ */
+ drm_warn(dev, "could not acquire memory region %pr\n", res);
+ mem = res;
+ }
+
screen_base = devm_ioremap_wc(&pdev->dev, mem->start,
resource_size(mem));
if (!screen_base)

144
patches/kernel/0013-fbdev-simplefb-Request-memory-region-in-driver.patch Normal file
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@ -0,0 +1,144 @@
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Thomas Zimmermann <tzimmermann@suse.de>
Date: Tue, 25 Jan 2022 10:12:21 +0100
Subject: [PATCH] fbdev/simplefb: Request memory region in driver
Requesting the framebuffer memory in simpledrm marks the memory
range as busy. This used to be done by the firmware sysfb code,
but the driver is the correct place.
v2:
* store memory region in struct for later cleanup (Javier)
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---
drivers/video/fbdev/simplefb.c | 65 +++++++++++++++++++++++-----------
1 file changed, 45 insertions(+), 20 deletions(-)
diff --git a/drivers/video/fbdev/simplefb.c b/drivers/video/fbdev/simplefb.c
index b63074fd892e..6885ac0203de 100644
--- a/drivers/video/fbdev/simplefb.c
+++ b/drivers/video/fbdev/simplefb.c
@@ -66,16 +66,36 @@ static int simplefb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
return 0;
}
-struct simplefb_par;
+struct simplefb_par {
+ u32 palette[PSEUDO_PALETTE_SIZE];
+ struct resource *mem;
+#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
+ bool clks_enabled;
+ unsigned int clk_count;
+ struct clk **clks;
+#endif
+#if defined CONFIG_OF && defined CONFIG_REGULATOR
+ bool regulators_enabled;
+ u32 regulator_count;
+ struct regulator **regulators;
+#endif
+};
+
static void simplefb_clocks_destroy(struct simplefb_par *par);
static void simplefb_regulators_destroy(struct simplefb_par *par);
static void simplefb_destroy(struct fb_info *info)
{
+ struct simplefb_par *par = info->par;
+ struct resource *mem = par->mem;
+
simplefb_regulators_destroy(info->par);
simplefb_clocks_destroy(info->par);
if (info->screen_base)
iounmap(info->screen_base);
+
+ if (mem)
+ release_mem_region(mem->start, resource_size(mem));
}
static const struct fb_ops simplefb_ops = {
@@ -169,20 +189,6 @@ static int simplefb_parse_pd(struct platform_device *pdev,
return 0;
}
-struct simplefb_par {
- u32 palette[PSEUDO_PALETTE_SIZE];
-#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
- bool clks_enabled;
- unsigned int clk_count;
- struct clk **clks;
-#endif
-#if defined CONFIG_OF && defined CONFIG_REGULATOR
- bool regulators_enabled;
- u32 regulator_count;
- struct regulator **regulators;
-#endif
-};
-
#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
/*
* Clock handling code.
@@ -405,7 +411,7 @@ static int simplefb_probe(struct platform_device *pdev)
struct simplefb_params params;
struct fb_info *info;
struct simplefb_par *par;
- struct resource *mem;
+ struct resource *res, *mem;
/*
* Generic drivers must not be registered if a framebuffer exists.
@@ -430,15 +436,28 @@ static int simplefb_probe(struct platform_device *pdev)
if (ret)
return ret;
- mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- if (!mem) {
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
dev_err(&pdev->dev, "No memory resource\n");
return -EINVAL;
}
+ mem = request_mem_region(res->start, resource_size(res), "simplefb");
+ if (!mem) {
+ /*
+ * We cannot make this fatal. Sometimes this comes from magic
+ * spaces our resource handlers simply don't know about. Use
+ * the I/O-memory resource as-is and try to map that instead.
+ */
+ dev_warn(&pdev->dev, "simplefb: cannot reserve video memory at %pR\n", res);
+ mem = res;
+ }
+
info = framebuffer_alloc(sizeof(struct simplefb_par), &pdev->dev);
- if (!info)
- return -ENOMEM;
+ if (!info) {
+ ret = -ENOMEM;
+ goto error_release_mem_region;
+ }
platform_set_drvdata(pdev, info);
par = info->par;
@@ -495,6 +514,9 @@ static int simplefb_probe(struct platform_device *pdev)
info->var.xres, info->var.yres,
info->var.bits_per_pixel, info->fix.line_length);
+ if (mem != res)
+ par->mem = mem; /* release in clean-up handler */
+
ret = register_framebuffer(info);
if (ret < 0) {
dev_err(&pdev->dev, "Unable to register simplefb: %d\n", ret);
@@ -513,6 +535,9 @@ static int simplefb_probe(struct platform_device *pdev)
iounmap(info->screen_base);
error_fb_release:
framebuffer_release(info);
+error_release_mem_region:
+ if (mem != res)
+ release_mem_region(mem->start, resource_size(mem));
return ret;
}