Nouveau - Mar 2020 - [PATCH v3] PCI: Use ioremap(), not phys_to_virt() for platform ROM

On some EFI systems, the video BIOS is provided by the EFI firmware.  The
boot stub code stores the physical address of the ROM image in pdev->rom.
Currently we attempt to access this pointer using phys_to_virt(), which
doesn't work with CONFIG_HIGHMEM.

On these systems, attempting to load the radeon module on a x86_32 kernel
can result in the following:

    BUG: unable to handle page fault for address: 3e8ed03c
    #PF: supervisor read access in kernel mode
    #PF: error_code(0x0000) - not-present page
    *pde = 00000000
    Oops: 0000 [#1] PREEMPT SMP
    CPU: 0 PID: 317 Comm: systemd-udevd Not tainted 5.6.0-rc3-next-20200228 #2
    Hardware name: Apple Computer, Inc. MacPro1,1/Mac-F4208DC8, BIOS    
MP11.88Z.005C.B08.0707021221 07/02/07
    EIP: radeon_get_bios+0x5ed/0xe50 [radeon]
    Code: 00 00 84 c0 0f 85 12 fd ff ff c7 87 64 01 00 00 00 00 00 00 8b 47 08
8b 55 b0 e8 1e 83 e1 d6 85 c0 74 1a 8b 55 c0 85 d2 74 13 <80> 38 55 75 0e
80 78 01 aa 0f 84 a4 03 00 00 8d 74 26 00 68 dc 06
    EAX: 3e8ed03c EBX: 00000000 ECX: 3e8ed03c EDX: 00010000
    ESI: 00040000 EDI: eec04000 EBP: eef3fc60 ESP: eef3fbe0
    DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010206
    CR0: 80050033 CR2: 3e8ed03c CR3: 2ec77000 CR4: 000006d0
    Call Trace:
     ? register_client+0x34/0xe0
     ? register_client+0xab/0xe0
     r520_init+0x26/0x240 [radeon]
     radeon_device_init+0x533/0xa50 [radeon]
     radeon_driver_load_kms+0x80/0x220 [radeon]
     drm_dev_register+0xa7/0x180 [drm]
     radeon_pci_probe+0x10f/0x1a0 [radeon]
     pci_device_probe+0xd4/0x140
     really_probe+0x13d/0x3b0
     driver_probe_device+0x56/0xd0
     device_driver_attach+0x49/0x50
     __driver_attach+0x79/0x130
     ? device_driver_attach+0x50/0x50
     bus_for_each_dev+0x5b/0xa0
     driver_attach+0x19/0x20
     ? device_driver_attach+0x50/0x50
     bus_add_driver+0x117/0x1d0
     ? pci_bus_num_vf+0x20/0x20
     driver_register+0x66/0xb0
     ? 0xf80f4000
     __pci_register_driver+0x3d/0x40
     radeon_init+0x82/0x1000 [radeon]
     do_one_initcall+0x42/0x200
     ? kvfree+0x25/0x30
     ? __vunmap+0x206/0x230
     ? kmem_cache_alloc_trace+0x16f/0x220
     ? do_init_module+0x21/0x220
     do_init_module+0x50/0x220
     load_module+0x1f26/0x2200
     sys_init_module+0x12d/0x160
     do_fast_syscall_32+0x82/0x250
     entry_SYSENTER_32+0xa5/0xf8

Fix the issue by updating all drivers which can access a platform
provided ROM. Instead of calling the helper function pci_platform_rom()
which uses phys_to_virt(), call ioremap() directly on the pdev->rom.

radeon_read_platform_bios() previously directly accessed an __iomem
pointer. Avoid this by calling memcpy_fromio() instead of kmemdup().

pci_platform_rom() now has no remaining callers, so remove it.

Signed-off-by: Mikel Rychliski <mikel at mikelr.com>
---

Tested on a MacPro 1,1 with a Radeon X1900 XT card and 32-bit kernel.

Changes in v3:
 - Inline pci_platform_rom()

Changes in v2:
 - Add iounmap() call in nouveau
 - Update function comment for pci_platform_rom()
 - Minor changes to commit messages

 drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c           | 31 +++++++++++++---------
 .../gpu/drm/nouveau/nvkm/subdev/bios/shadowpci.c   | 17 ++++++++++--
 drivers/gpu/drm/radeon/radeon_bios.c               | 30 +++++++++++++--------
 drivers/pci/rom.c                                  | 17 ------------
 include/linux/pci.h                                |  1 -
 5 files changed, 52 insertions(+), 44 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
index 50dff69a0f6e..b1172d93c99c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
@@ -192,30 +192,35 @@ static bool amdgpu_read_bios_from_rom(struct amdgpu_device
*adev)
 
 static bool amdgpu_read_platform_bios(struct amdgpu_device *adev)
 {
-	uint8_t __iomem *bios;
-	size_t size;
+	phys_addr_t rom = adev->pdev->rom;
+	size_t romlen = adev->pdev->romlen;
+	void __iomem *bios;
 
 	adev->bios = NULL;
 
-	bios = pci_platform_rom(adev->pdev, &size);
-	if (!bios) {
+	if (!rom || romlen == 0)
 		return false;
-	}
 
-	adev->bios = kzalloc(size, GFP_KERNEL);
-	if (adev->bios == NULL)
+	adev->bios = kzalloc(romlen, GFP_KERNEL);
+	if (!adev->bios)
 		return false;
 
-	memcpy_fromio(adev->bios, bios, size);
+	bios = ioremap(rom, romlen);
+	if (!bios)
+		goto free_bios;
 
-	if (!check_atom_bios(adev->bios, size)) {
-		kfree(adev->bios);
-		return false;
-	}
+	memcpy_fromio(adev->bios, bios, romlen);
+	iounmap(bios);
 
-	adev->bios_size = size;
+	if (!check_atom_bios(adev->bios, romlen))
+		goto free_bios;
+
+	adev->bios_size = romlen;
 
 	return true;
+free_bios:
+	kfree(adev->bios);
+	return false;
 }
 
 #ifdef CONFIG_ACPI
diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowpci.c
b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowpci.c
index 9b91da09dc5f..8d9812a51ef6 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowpci.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowpci.c
@@ -101,9 +101,13 @@ platform_init(struct nvkm_bios *bios, const char *name)
 	else
 		return ERR_PTR(-ENODEV);
 
+	if (!pdev->rom || pdev->romlen == 0)
+		return ERR_PTR(-ENODEV);
+
 	if ((priv = kmalloc(sizeof(*priv), GFP_KERNEL))) {
+		priv->size = pdev->romlen;
 		if (ret = -ENODEV,
-		    (priv->rom = pci_platform_rom(pdev, &priv->size)))
+		    (priv->rom = ioremap(pdev->rom, pdev->romlen)))
 			return priv;
 		kfree(priv);
 	}
@@ -111,11 +115,20 @@ platform_init(struct nvkm_bios *bios, const char *name)
 	return ERR_PTR(ret);
 }
 
+static void
+platform_fini(void *data)
+{
+	struct priv *priv = data;
+
+	iounmap(priv->rom);
+	kfree(priv);
+}
+
 const struct nvbios_source
 nvbios_platform = {
 	.name = "PLATFORM",
 	.init = platform_init,
-	.fini = (void(*)(void *))kfree,
+	.fini = platform_fini,
 	.read = pcirom_read,
 	.rw = true,
 };
diff --git a/drivers/gpu/drm/radeon/radeon_bios.c
b/drivers/gpu/drm/radeon/radeon_bios.c
index c42f73fad3e3..bb29cf02974d 100644
--- a/drivers/gpu/drm/radeon/radeon_bios.c
+++ b/drivers/gpu/drm/radeon/radeon_bios.c
@@ -108,25 +108,33 @@ static bool radeon_read_bios(struct radeon_device *rdev)
 
 static bool radeon_read_platform_bios(struct radeon_device *rdev)
 {
-	uint8_t __iomem *bios;
-	size_t size;
+	phys_addr_t rom = rdev->pdev->rom;
+	size_t romlen = rdev->pdev->romlen;
+	void __iomem *bios;
 
 	rdev->bios = NULL;
 
-	bios = pci_platform_rom(rdev->pdev, &size);
-	if (!bios) {
+	if (!rom || romlen == 0)
 		return false;
-	}
 
-	if (size == 0 || bios[0] != 0x55 || bios[1] != 0xaa) {
+	rdev->bios = kzalloc(romlen, GFP_KERNEL);
+	if (!rdev->bios)
 		return false;
-	}
-	rdev->bios = kmemdup(bios, size, GFP_KERNEL);
-	if (rdev->bios == NULL) {
-		return false;
-	}
+
+	bios = ioremap(rom, romlen);
+	if (!bios)
+		goto free_bios;
+
+	memcpy_fromio(rdev->bios, bios, romlen);
+	iounmap(bios);
+
+	if (rdev->bios[0] != 0x55 || rdev->bios[1] != 0xaa)
+		goto free_bios;
 
 	return true;
+free_bios:
+	kfree(rdev->bios);
+	return false;
 }
 
 #ifdef CONFIG_ACPI
diff --git a/drivers/pci/rom.c b/drivers/pci/rom.c
index 137bf0cee897..8fc9a4e911e3 100644
--- a/drivers/pci/rom.c
+++ b/drivers/pci/rom.c
@@ -195,20 +195,3 @@ void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom)
 		pci_disable_rom(pdev);
 }
 EXPORT_SYMBOL(pci_unmap_rom);
-
-/**
- * pci_platform_rom - provides a pointer to any ROM image provided by the
- * platform
- * @pdev: pointer to pci device struct
- * @size: pointer to receive size of pci window over ROM
- */
-void __iomem *pci_platform_rom(struct pci_dev *pdev, size_t *size)
-{
-	if (pdev->rom && pdev->romlen) {
-		*size = pdev->romlen;
-		return phys_to_virt((phys_addr_t)pdev->rom);
-	}
-
-	return NULL;
-}
-EXPORT_SYMBOL(pci_platform_rom);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 3840a541a9de..7268dcf1f23e 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1214,7 +1214,6 @@ int pci_enable_rom(struct pci_dev *pdev);
 void pci_disable_rom(struct pci_dev *pdev);
 void __iomem __must_check *pci_map_rom(struct pci_dev *pdev, size_t *size);
 void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom);
-void __iomem __must_check *pci_platform_rom(struct pci_dev *pdev, size_t
*size);
 
 /* Power management related routines */
 int pci_save_state(struct pci_dev *dev);
-- 
2.13.7

On Wed, Mar 18, 2020 at 10:16:23PM -0400, Mikel Rychliski
wrote:
> On some EFI systems, the video BIOS is provided by the EFI firmware.  The
> boot stub code stores the physical address of the ROM image in
pdev->rom.
> Currently we attempt to access this pointer using phys_to_virt(), which
> doesn't work with CONFIG_HIGHMEM.
> 
> On these systems, attempting to load the radeon module on a x86_32 kernel
> can result in the following:
> 
>     BUG: unable to handle page fault for address: 3e8ed03c
>     #PF: supervisor read access in kernel mode
>     #PF: error_code(0x0000) - not-present page
>     *pde = 00000000
>     Oops: 0000 [#1] PREEMPT SMP
>     CPU: 0 PID: 317 Comm: systemd-udevd Not tainted 5.6.0-rc3-next-20200228
#2
>     Hardware name: Apple Computer, Inc. MacPro1,1/Mac-F4208DC8, BIOS    
MP11.88Z.005C.B08.0707021221 07/02/07
>     EIP: radeon_get_bios+0x5ed/0xe50 [radeon]
>     Code: 00 00 84 c0 0f 85 12 fd ff ff c7 87 64 01 00 00 00 00 00 00 8b 47
08 8b 55 b0 e8 1e 83 e1 d6 85 c0 74 1a 8b 55 c0 85 d2 74 13 <80> 38 55 75
0e 80 78 01 aa 0f 84 a4 03 00 00 8d 74 26 00 68 dc 06
>     EAX: 3e8ed03c EBX: 00000000 ECX: 3e8ed03c EDX: 00010000
>     ESI: 00040000 EDI: eec04000 EBP: eef3fc60 ESP: eef3fbe0
>     DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010206
>     CR0: 80050033 CR2: 3e8ed03c CR3: 2ec77000 CR4: 000006d0
>     Call Trace:
>      ? register_client+0x34/0xe0
>      ? register_client+0xab/0xe0
>      r520_init+0x26/0x240 [radeon]
>      radeon_device_init+0x533/0xa50 [radeon]
>      radeon_driver_load_kms+0x80/0x220 [radeon]
>      drm_dev_register+0xa7/0x180 [drm]
>      radeon_pci_probe+0x10f/0x1a0 [radeon]
>      pci_device_probe+0xd4/0x140
>      really_probe+0x13d/0x3b0
>      driver_probe_device+0x56/0xd0
>      device_driver_attach+0x49/0x50
>      __driver_attach+0x79/0x130
>      ? device_driver_attach+0x50/0x50
>      bus_for_each_dev+0x5b/0xa0
>      driver_attach+0x19/0x20
>      ? device_driver_attach+0x50/0x50
>      bus_add_driver+0x117/0x1d0
>      ? pci_bus_num_vf+0x20/0x20
>      driver_register+0x66/0xb0
>      ? 0xf80f4000
>      __pci_register_driver+0x3d/0x40
>      radeon_init+0x82/0x1000 [radeon]
>      do_one_initcall+0x42/0x200
>      ? kvfree+0x25/0x30
>      ? __vunmap+0x206/0x230
>      ? kmem_cache_alloc_trace+0x16f/0x220
>      ? do_init_module+0x21/0x220
>      do_init_module+0x50/0x220
>      load_module+0x1f26/0x2200
>      sys_init_module+0x12d/0x160
>      do_fast_syscall_32+0x82/0x250
>      entry_SYSENTER_32+0xa5/0xf8
> 
> Fix the issue by updating all drivers which can access a platform
> provided ROM. Instead of calling the helper function pci_platform_rom()
> which uses phys_to_virt(), call ioremap() directly on the pdev->rom.
> 
> radeon_read_platform_bios() previously directly accessed an __iomem
> pointer. Avoid this by calling memcpy_fromio() instead of kmemdup().
> 
> pci_platform_rom() now has no remaining callers, so remove it.
> 
> Signed-off-by: Mikel Rychliski <mikel at mikelr.com>
I applied this to pci/resource for v5.7.  I would feel better if some
of the graphics guys chimed in, or even applied it via the DRM tree
since most of the changes are actually in drivers/gpu.

Feel free to add my

  Acked-by: Bjorn Helgaas <bhelgaas at google.com>

and let me know if you do that.
> ---
> 
> Tested on a MacPro 1,1 with a Radeon X1900 XT card and 32-bit kernel.
> 
> Changes in v3:
>  - Inline pci_platform_rom()
> 
> Changes in v2:
>  - Add iounmap() call in nouveau
>  - Update function comment for pci_platform_rom()
>  - Minor changes to commit messages
> 
>  drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c           | 31
+++++++++++++---------
>  .../gpu/drm/nouveau/nvkm/subdev/bios/shadowpci.c   | 17 ++++++++++--
>  drivers/gpu/drm/radeon/radeon_bios.c               | 30
+++++++++++++--------
>  drivers/pci/rom.c                                  | 17 ------------
>  include/linux/pci.h                                |  1 -
>  5 files changed, 52 insertions(+), 44 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
> index 50dff69a0f6e..b1172d93c99c 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
> @@ -192,30 +192,35 @@ static bool amdgpu_read_bios_from_rom(struct
amdgpu_device *adev)
>  
>  static bool amdgpu_read_platform_bios(struct amdgpu_device *adev)
>  {
> -	uint8_t __iomem *bios;
> -	size_t size;
> +	phys_addr_t rom = adev->pdev->rom;
> +	size_t romlen = adev->pdev->romlen;
> +	void __iomem *bios;
>  
>  	adev->bios = NULL;
>  
> -	bios = pci_platform_rom(adev->pdev, &size);
> -	if (!bios) {
> +	if (!rom || romlen == 0)
>  		return false;
> -	}
>  
> -	adev->bios = kzalloc(size, GFP_KERNEL);
> -	if (adev->bios == NULL)
> +	adev->bios = kzalloc(romlen, GFP_KERNEL);
> +	if (!adev->bios)
>  		return false;
>  
> -	memcpy_fromio(adev->bios, bios, size);
> +	bios = ioremap(rom, romlen);
> +	if (!bios)
> +		goto free_bios;
>  
> -	if (!check_atom_bios(adev->bios, size)) {
> -		kfree(adev->bios);
> -		return false;
> -	}
> +	memcpy_fromio(adev->bios, bios, romlen);
> +	iounmap(bios);
>  
> -	adev->bios_size = size;
> +	if (!check_atom_bios(adev->bios, romlen))
> +		goto free_bios;
> +
> +	adev->bios_size = romlen;
>  
>  	return true;
> +free_bios:
> +	kfree(adev->bios);
> +	return false;
>  }
>  
>  #ifdef CONFIG_ACPI
> diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowpci.c
b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowpci.c
> index 9b91da09dc5f..8d9812a51ef6 100644
> --- a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowpci.c
> +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowpci.c
> @@ -101,9 +101,13 @@ platform_init(struct nvkm_bios *bios, const char
*name)
>  	else
>  		return ERR_PTR(-ENODEV);
>  
> +	if (!pdev->rom || pdev->romlen == 0)
> +		return ERR_PTR(-ENODEV);
> +
>  	if ((priv = kmalloc(sizeof(*priv), GFP_KERNEL))) {
> +		priv->size = pdev->romlen;
>  		if (ret = -ENODEV,
> -		    (priv->rom = pci_platform_rom(pdev, &priv->size)))
> +		    (priv->rom = ioremap(pdev->rom, pdev->romlen)))
>  			return priv;
>  		kfree(priv);
>  	}
> @@ -111,11 +115,20 @@ platform_init(struct nvkm_bios *bios, const char
*name)
>  	return ERR_PTR(ret);
>  }
>  
> +static void
> +platform_fini(void *data)
> +{
> +	struct priv *priv = data;
> +
> +	iounmap(priv->rom);
> +	kfree(priv);
> +}
> +
>  const struct nvbios_source
>  nvbios_platform = {
>  	.name = "PLATFORM",
>  	.init = platform_init,
> -	.fini = (void(*)(void *))kfree,
> +	.fini = platform_fini,
>  	.read = pcirom_read,
>  	.rw = true,
>  };
> diff --git a/drivers/gpu/drm/radeon/radeon_bios.c
b/drivers/gpu/drm/radeon/radeon_bios.c
> index c42f73fad3e3..bb29cf02974d 100644
> --- a/drivers/gpu/drm/radeon/radeon_bios.c
> +++ b/drivers/gpu/drm/radeon/radeon_bios.c
> @@ -108,25 +108,33 @@ static bool radeon_read_bios(struct radeon_device
*rdev)
>  
>  static bool radeon_read_platform_bios(struct radeon_device *rdev)
>  {
> -	uint8_t __iomem *bios;
> -	size_t size;
> +	phys_addr_t rom = rdev->pdev->rom;
> +	size_t romlen = rdev->pdev->romlen;
> +	void __iomem *bios;
>  
>  	rdev->bios = NULL;
>  
> -	bios = pci_platform_rom(rdev->pdev, &size);
> -	if (!bios) {
> +	if (!rom || romlen == 0)
>  		return false;
> -	}
>  
> -	if (size == 0 || bios[0] != 0x55 || bios[1] != 0xaa) {
> +	rdev->bios = kzalloc(romlen, GFP_KERNEL);
> +	if (!rdev->bios)
>  		return false;
> -	}
> -	rdev->bios = kmemdup(bios, size, GFP_KERNEL);
> -	if (rdev->bios == NULL) {
> -		return false;
> -	}
> +
> +	bios = ioremap(rom, romlen);
> +	if (!bios)
> +		goto free_bios;
> +
> +	memcpy_fromio(rdev->bios, bios, romlen);
> +	iounmap(bios);
> +
> +	if (rdev->bios[0] != 0x55 || rdev->bios[1] != 0xaa)
> +		goto free_bios;
>  
>  	return true;
> +free_bios:
> +	kfree(rdev->bios);
> +	return false;
>  }
>  
>  #ifdef CONFIG_ACPI
> diff --git a/drivers/pci/rom.c b/drivers/pci/rom.c
> index 137bf0cee897..8fc9a4e911e3 100644
> --- a/drivers/pci/rom.c
> +++ b/drivers/pci/rom.c
> @@ -195,20 +195,3 @@ void pci_unmap_rom(struct pci_dev *pdev, void __iomem
*rom)
>  		pci_disable_rom(pdev);
>  }
>  EXPORT_SYMBOL(pci_unmap_rom);
> -
> -/**
> - * pci_platform_rom - provides a pointer to any ROM image provided by the
> - * platform
> - * @pdev: pointer to pci device struct
> - * @size: pointer to receive size of pci window over ROM
> - */
> -void __iomem *pci_platform_rom(struct pci_dev *pdev, size_t *size)
> -{
> -	if (pdev->rom && pdev->romlen) {
> -		*size = pdev->romlen;
> -		return phys_to_virt((phys_addr_t)pdev->rom);
> -	}
> -
> -	return NULL;
> -}
> -EXPORT_SYMBOL(pci_platform_rom);
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 3840a541a9de..7268dcf1f23e 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1214,7 +1214,6 @@ int pci_enable_rom(struct pci_dev *pdev);
>  void pci_disable_rom(struct pci_dev *pdev);
>  void __iomem __must_check *pci_map_rom(struct pci_dev *pdev, size_t
*size);
>  void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom);
> -void __iomem __must_check *pci_platform_rom(struct pci_dev *pdev, size_t
*size);
>  
>  /* Power management related routines */
>  int pci_save_state(struct pci_dev *dev);
> -- 
> 2.13.7
>

[AMD Public Use]
> -----Original Message-----
> From: Bjorn Helgaas <helgaas at kernel.org>
> Sent: Saturday, March 28, 2020 4:19 PM
> To: Mikel Rychliski <mikel at mikelr.com>
> Cc: amd-gfx at lists.freedesktop.org; linux-pci at vger.kernel.org;
> nouveau at lists.freedesktop.org; Deucher, Alexander
> <Alexander.Deucher at amd.com>; Koenig, Christian
> <Christian.Koenig at amd.com>; Zhou, David(ChunMing)
> <David1.Zhou at amd.com>; Matthew Garrett
> <matthewgarrett at google.com>; Ben Skeggs <bskeggs at
redhat.com>;
> Christoph Hellwig <hch at lst.de>
> Subject: Re: [PATCH v3] PCI: Use ioremap(), not phys_to_virt() for platform
> ROM
> 
> On Wed, Mar 18, 2020 at 10:16:23PM -0400, Mikel Rychliski wrote:
> > On some EFI systems, the video BIOS is provided by the EFI firmware.
> > The boot stub code stores the physical address of the ROM image in
pdev-
> >rom.
> > Currently we attempt to access this pointer using phys_to_virt(),
> > which doesn't work with CONFIG_HIGHMEM.
> >
> > On these systems, attempting to load the radeon module on a x86_32
> > kernel can result in the following:
> >
> >     BUG: unable to handle page fault for address: 3e8ed03c
> >     #PF: supervisor read access in kernel mode
> >     #PF: error_code(0x0000) - not-present page
> >     *pde = 00000000
> >     Oops: 0000 [#1] PREEMPT SMP
> >     CPU: 0 PID: 317 Comm: systemd-udevd Not tainted 5.6.0-rc3-next-
> 20200228 #2
> >     Hardware name: Apple Computer, Inc. MacPro1,1/Mac-F4208DC8, BIOS
> MP11.88Z.005C.B08.0707021221 07/02/07
> >     EIP: radeon_get_bios+0x5ed/0xe50 [radeon]
> >     Code: 00 00 84 c0 0f 85 12 fd ff ff c7 87 64 01 00 00 00 00 00 00
8b 47 08 8b
> 55 b0 e8 1e 83 e1 d6 85 c0 74 1a 8b 55 c0 85 d2 74 13 <80> 38 55 75
0e 80 78 01
> aa 0f 84 a4 03 00 00 8d 74 26 00 68 dc 06
> >     EAX: 3e8ed03c EBX: 00000000 ECX: 3e8ed03c EDX: 00010000
> >     ESI: 00040000 EDI: eec04000 EBP: eef3fc60 ESP: eef3fbe0
> >     DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010206
> >     CR0: 80050033 CR2: 3e8ed03c CR3: 2ec77000 CR4: 000006d0
> >     Call Trace:
> >      ? register_client+0x34/0xe0
> >      ? register_client+0xab/0xe0
> >      r520_init+0x26/0x240 [radeon]
> >      radeon_device_init+0x533/0xa50 [radeon]
> >      radeon_driver_load_kms+0x80/0x220 [radeon]
> >      drm_dev_register+0xa7/0x180 [drm]
> >      radeon_pci_probe+0x10f/0x1a0 [radeon]
> >      pci_device_probe+0xd4/0x140
> >      really_probe+0x13d/0x3b0
> >      driver_probe_device+0x56/0xd0
> >      device_driver_attach+0x49/0x50
> >      __driver_attach+0x79/0x130
> >      ? device_driver_attach+0x50/0x50
> >      bus_for_each_dev+0x5b/0xa0
> >      driver_attach+0x19/0x20
> >      ? device_driver_attach+0x50/0x50
> >      bus_add_driver+0x117/0x1d0
> >      ? pci_bus_num_vf+0x20/0x20
> >      driver_register+0x66/0xb0
> >      ? 0xf80f4000
> >      __pci_register_driver+0x3d/0x40
> >      radeon_init+0x82/0x1000 [radeon]
> >      do_one_initcall+0x42/0x200
> >      ? kvfree+0x25/0x30
> >      ? __vunmap+0x206/0x230
> >      ? kmem_cache_alloc_trace+0x16f/0x220
> >      ? do_init_module+0x21/0x220
> >      do_init_module+0x50/0x220
> >      load_module+0x1f26/0x2200
> >      sys_init_module+0x12d/0x160
> >      do_fast_syscall_32+0x82/0x250
> >      entry_SYSENTER_32+0xa5/0xf8
> >
> > Fix the issue by updating all drivers which can access a platform
> > provided ROM. Instead of calling the helper function
> > pci_platform_rom() which uses phys_to_virt(), call ioremap() directly
on
> the pdev->rom.
> >
> > radeon_read_platform_bios() previously directly accessed an __iomem
> > pointer. Avoid this by calling memcpy_fromio() instead of kmemdup().
> >
> > pci_platform_rom() now has no remaining callers, so remove it.
> >
> > Signed-off-by: Mikel Rychliski <mikel at mikelr.com>
> 
> I applied this to pci/resource for v5.7.  I would feel better if some of
the
> graphics guys chimed in, or even applied it via the DRM tree since most of
the
> changes are actually in drivers/gpu.
Feel free to take it through the PCI tree.  These areas of radeon and amdgpu
don't really change much at all so, I'm not too concerned about a
conflict.

Acked-by: Alex Deucher <alexander.deucher at amd.com>
> 
> Feel free to add my
> 
>   Acked-by: Bjorn Helgaas <bhelgaas at google.com>
> 
> and let me know if you do that.
> 
> > ---
> >
> > Tested on a MacPro 1,1 with a Radeon X1900 XT card and 32-bit kernel.
> >
> > Changes in v3:
> >  - Inline pci_platform_rom()
> >
> > Changes in v2:
> >  - Add iounmap() call in nouveau
> >  - Update function comment for pci_platform_rom()
> >  - Minor changes to commit messages
> >
> >  drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c           | 31
> +++++++++++++---------
> >  .../gpu/drm/nouveau/nvkm/subdev/bios/shadowpci.c   | 17 ++++++++++-
> -
> >  drivers/gpu/drm/radeon/radeon_bios.c               | 30
+++++++++++++-------
> -
> >  drivers/pci/rom.c                                  | 17 ------------
> >  include/linux/pci.h                                |  1 -
> >  5 files changed, 52 insertions(+), 44 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
> > b/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
> > index 50dff69a0f6e..b1172d93c99c 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
> > @@ -192,30 +192,35 @@ static bool amdgpu_read_bios_from_rom(struct
> > amdgpu_device *adev)
> >
> >  static bool amdgpu_read_platform_bios(struct amdgpu_device *adev)  {
> > -	uint8_t __iomem *bios;
> > -	size_t size;
> > +	phys_addr_t rom = adev->pdev->rom;
> > +	size_t romlen = adev->pdev->romlen;
> > +	void __iomem *bios;
> >
> >  	adev->bios = NULL;
> >
> > -	bios = pci_platform_rom(adev->pdev, &size);
> > -	if (!bios) {
> > +	if (!rom || romlen == 0)
> >  		return false;
> > -	}
> >
> > -	adev->bios = kzalloc(size, GFP_KERNEL);
> > -	if (adev->bios == NULL)
> > +	adev->bios = kzalloc(romlen, GFP_KERNEL);
> > +	if (!adev->bios)
> >  		return false;
> >
> > -	memcpy_fromio(adev->bios, bios, size);
> > +	bios = ioremap(rom, romlen);
> > +	if (!bios)
> > +		goto free_bios;
> >
> > -	if (!check_atom_bios(adev->bios, size)) {
> > -		kfree(adev->bios);
> > -		return false;
> > -	}
> > +	memcpy_fromio(adev->bios, bios, romlen);
> > +	iounmap(bios);
> >
> > -	adev->bios_size = size;
> > +	if (!check_atom_bios(adev->bios, romlen))
> > +		goto free_bios;
> > +
> > +	adev->bios_size = romlen;
> >
> >  	return true;
> > +free_bios:
> > +	kfree(adev->bios);
> > +	return false;
> >  }
> >
> >  #ifdef CONFIG_ACPI
> > diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowpci.c
> > b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowpci.c
> > index 9b91da09dc5f..8d9812a51ef6 100644
> > --- a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowpci.c
> > +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowpci.c
> > @@ -101,9 +101,13 @@ platform_init(struct nvkm_bios *bios, const char
> *name)
> >  	else
> >  		return ERR_PTR(-ENODEV);
> >
> > +	if (!pdev->rom || pdev->romlen == 0)
> > +		return ERR_PTR(-ENODEV);
> > +
> >  	if ((priv = kmalloc(sizeof(*priv), GFP_KERNEL))) {
> > +		priv->size = pdev->romlen;
> >  		if (ret = -ENODEV,
> > -		    (priv->rom = pci_platform_rom(pdev, &priv->size)))
> > +		    (priv->rom = ioremap(pdev->rom, pdev->romlen)))
> >  			return priv;
> >  		kfree(priv);
> >  	}
> > @@ -111,11 +115,20 @@ platform_init(struct nvkm_bios *bios, const char
> *name)
> >  	return ERR_PTR(ret);
> >  }
> >
> > +static void
> > +platform_fini(void *data)
> > +{
> > +	struct priv *priv = data;
> > +
> > +	iounmap(priv->rom);
> > +	kfree(priv);
> > +}
> > +
> >  const struct nvbios_source
> >  nvbios_platform = {
> >  	.name = "PLATFORM",
> >  	.init = platform_init,
> > -	.fini = (void(*)(void *))kfree,
> > +	.fini = platform_fini,
> >  	.read = pcirom_read,
> >  	.rw = true,
> >  };
> > diff --git a/drivers/gpu/drm/radeon/radeon_bios.c
> > b/drivers/gpu/drm/radeon/radeon_bios.c
> > index c42f73fad3e3..bb29cf02974d 100644
> > --- a/drivers/gpu/drm/radeon/radeon_bios.c
> > +++ b/drivers/gpu/drm/radeon/radeon_bios.c
> > @@ -108,25 +108,33 @@ static bool radeon_read_bios(struct
> > radeon_device *rdev)
> >
> >  static bool radeon_read_platform_bios(struct radeon_device *rdev)  {
> > -	uint8_t __iomem *bios;
> > -	size_t size;
> > +	phys_addr_t rom = rdev->pdev->rom;
> > +	size_t romlen = rdev->pdev->romlen;
> > +	void __iomem *bios;
> >
> >  	rdev->bios = NULL;
> >
> > -	bios = pci_platform_rom(rdev->pdev, &size);
> > -	if (!bios) {
> > +	if (!rom || romlen == 0)
> >  		return false;
> > -	}
> >
> > -	if (size == 0 || bios[0] != 0x55 || bios[1] != 0xaa) {
> > +	rdev->bios = kzalloc(romlen, GFP_KERNEL);
> > +	if (!rdev->bios)
> >  		return false;
> > -	}
> > -	rdev->bios = kmemdup(bios, size, GFP_KERNEL);
> > -	if (rdev->bios == NULL) {
> > -		return false;
> > -	}
> > +
> > +	bios = ioremap(rom, romlen);
> > +	if (!bios)
> > +		goto free_bios;
> > +
> > +	memcpy_fromio(rdev->bios, bios, romlen);
> > +	iounmap(bios);
> > +
> > +	if (rdev->bios[0] != 0x55 || rdev->bios[1] != 0xaa)
> > +		goto free_bios;
> >
> >  	return true;
> > +free_bios:
> > +	kfree(rdev->bios);
> > +	return false;
> >  }
> >
> >  #ifdef CONFIG_ACPI
> > diff --git a/drivers/pci/rom.c b/drivers/pci/rom.c index
> > 137bf0cee897..8fc9a4e911e3 100644
> > --- a/drivers/pci/rom.c
> > +++ b/drivers/pci/rom.c
> > @@ -195,20 +195,3 @@ void pci_unmap_rom(struct pci_dev *pdev, void
> __iomem *rom)
> >  		pci_disable_rom(pdev);
> >  }
> >  EXPORT_SYMBOL(pci_unmap_rom);
> > -
> > -/**
> > - * pci_platform_rom - provides a pointer to any ROM image provided by
> > the
> > - * platform
> > - * @pdev: pointer to pci device struct
> > - * @size: pointer to receive size of pci window over ROM
> > - */
> > -void __iomem *pci_platform_rom(struct pci_dev *pdev, size_t *size) -{
> > -	if (pdev->rom && pdev->romlen) {
> > -		*size = pdev->romlen;
> > -		return phys_to_virt((phys_addr_t)pdev->rom);
> > -	}
> > -
> > -	return NULL;
> > -}
> > -EXPORT_SYMBOL(pci_platform_rom);
> > diff --git a/include/linux/pci.h b/include/linux/pci.h index
> > 3840a541a9de..7268dcf1f23e 100644
> > --- a/include/linux/pci.h
> > +++ b/include/linux/pci.h
> > @@ -1214,7 +1214,6 @@ int pci_enable_rom(struct pci_dev *pdev);  void
> > pci_disable_rom(struct pci_dev *pdev);  void __iomem __must_check
> > *pci_map_rom(struct pci_dev *pdev, size_t *size);  void
> > pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom); -void
> __iomem
> > __must_check *pci_platform_rom(struct pci_dev *pdev, size_t *size);
> >
> >  /* Power management related routines */  int pci_save_state(struct
> > pci_dev *dev);
> > --
> > 2.13.7
> >