Re: [PATCH v3] PCI: Use ioremap(), not phys_to_virt() for platform ROM

[Bjorn Helgaas <helgaas@kernel.org>]

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@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@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
> 
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