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

[Bjorn Helgaas <helgaas@kernel.org>]

On Mon, Mar 30, 2020 at 01:54:33PM +0000, Deucher, Alexander wrote:
> > -----Original Message-----
> > From: Bjorn Helgaas <helgaas@kernel.org>
> > Sent: Saturday, March 28, 2020 4:19 PM
> > To: Mikel Rychliski <mikel@mikelr.com>
> > Cc: amd-gfx@lists.freedesktop.org; linux-pci@vger.kernel.org;
> > nouveau@lists.freedesktop.org; Deucher, Alexander
> > <Alexander.Deucher@amd.com>; Koenig, Christian
> > <Christian.Koenig@amd.com>; Zhou, David(ChunMing)
> > <David1.Zhou@amd.com>; Matthew Garrett
> > <matthewgarrett@google.com>; Ben Skeggs <bskeggs@redhat.com>;
> > Christoph Hellwig <hch@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@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@amd.com>

Thanks, I added your ack, and this is queued up for v5.7.

> > 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
> > >