From: Bjorn Helgaas <helgaas@kernel.org>
To: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: LKML <linux-kernel@vger.kernel.org>,
"Stephen Rothwell" <sfr@canb.auug.org.au>,
linux-samsung-soc@vger.kernel.org, "Jan Kara" <jack@suse.cz>,
"Kees Cook" <keescook@chromium.org>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
linux-pci@vger.kernel.org,
"DRI Development" <dri-devel@lists.freedesktop.org>,
linux-mm@kvack.org, "Jason Gunthorpe" <jgg@ziepe.ca>,
"Jérôme Glisse" <jglisse@redhat.com>,
"John Hubbard" <jhubbard@nvidia.com>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Daniel Vetter" <daniel.vetter@intel.com>,
"Dan Williams" <dan.j.williams@intel.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
linux-arm-kernel@lists.infradead.org,
linux-media@vger.kernel.org
Subject: Re: [PATCH 2/2] PCI: Revoke mappings like devmem
Date: Wed, 10 Feb 2021 16:20:29 -0600 [thread overview]
Message-ID: <20210210222029.GA612769@bjorn-Precision-5520> (raw)
In-Reply-To: <20210204165831.2703772-3-daniel.vetter@ffwll.ch>
I see I already acked this, but if you haven't merged it yet there are
a few typos in the commit log:
On Thu, Feb 04, 2021 at 05:58:31PM +0100, Daniel Vetter wrote:
> Since 3234ac664a87 ("/dev/mem: Revoke mappings when a driver claims
> the region") /dev/kmem zaps ptes when the kernel requests exclusive
> acccess to an iomem region. And with CONFIG_IO_STRICT_DEVMEM, this is
> the default for all driver uses.
s/ptes/PTEs/
> Except there's two more ways to access PCI BARs: sysfs and proc mmap
> support. Let's plug that hole.
s/there's two/there are two/
> For revoke_devmem() to work we need to link our vma into the same
> address_space, with consistent vma->vm_pgoff. ->pgoff is already
> adjusted, because that's how (io_)remap_pfn_range works, but for the
> mapping we need to adjust vma->vm_file->f_mapping. The cleanest way is
> to adjust this at at ->open time:
>
> - for sysfs this is easy, now that binary attributes support this. We
> just set bin_attr->mapping when mmap is supported
> - for procfs it's a bit more tricky, since procfs pci access has only
> one file per device, and access to a specific resources first needs
> to be set up with some ioctl calls. But mmap is only supported for
> the same resources as sysfs exposes with mmap support, and otherwise
> rejected, so we can set the mapping unconditionally at open time
> without harm.
s/pci access/PCI access/
s/a specific resources/a specific resource/
> A special consideration is for arch_can_pci_mmap_io() - we need to
> make sure that the ->f_mapping doesn't alias between ioport and iomem
> space. There's only 2 ways in-tree to support mmap of ioports: generic
> pci mmap (ARCH_GENERIC_PCI_MMAP_RESOURCE), and sparc as the single
> architecture hand-rolling. Both approach support ioport mmap through a
> special pfn range and not through magic pte attributes. Aliasing is
> therefore not a problem.
s/There's only 2/There are only two/
s/pci mmap/PCI mmap/
s/Both approach/Both approaches/
s/pfn/PFN/
s/pte/PTE/
> The only difference in access checks left is that sysfs PCI mmap does
> not check for CAP_RAWIO. I'm not really sure whether that should be
> added or not.
>
> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
> Reviewed-by: Dan Williams <dan.j.williams@intel.com>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> Cc: Stephen Rothwell <sfr@canb.auug.org.au>
> Cc: Jason Gunthorpe <jgg@ziepe.ca>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: John Hubbard <jhubbard@nvidia.com>
> Cc: Jérôme Glisse <jglisse@redhat.com>
> Cc: Jan Kara <jack@suse.cz>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: linux-mm@kvack.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-samsung-soc@vger.kernel.org
> Cc: linux-media@vger.kernel.org
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: linux-pci@vger.kernel.org
> ---
> drivers/pci/pci-sysfs.c | 4 ++++
> drivers/pci/proc.c | 1 +
> 2 files changed, 5 insertions(+)
>
> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index 0c45b4f7b214..f8afd54ca3e1 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -942,6 +942,7 @@ void pci_create_legacy_files(struct pci_bus *b)
> b->legacy_io->read = pci_read_legacy_io;
> b->legacy_io->write = pci_write_legacy_io;
> b->legacy_io->mmap = pci_mmap_legacy_io;
> + b->legacy_io->mapping = iomem_get_mapping();
> pci_adjust_legacy_attr(b, pci_mmap_io);
> error = device_create_bin_file(&b->dev, b->legacy_io);
> if (error)
> @@ -954,6 +955,7 @@ void pci_create_legacy_files(struct pci_bus *b)
> b->legacy_mem->size = 1024*1024;
> b->legacy_mem->attr.mode = 0600;
> b->legacy_mem->mmap = pci_mmap_legacy_mem;
> + b->legacy_io->mapping = iomem_get_mapping();
> pci_adjust_legacy_attr(b, pci_mmap_mem);
> error = device_create_bin_file(&b->dev, b->legacy_mem);
> if (error)
> @@ -1169,6 +1171,8 @@ static int pci_create_attr(struct pci_dev *pdev, int num, int write_combine)
> res_attr->mmap = pci_mmap_resource_uc;
> }
> }
> + if (res_attr->mmap)
> + res_attr->mapping = iomem_get_mapping();
> res_attr->attr.name = res_attr_name;
> res_attr->attr.mode = 0600;
> res_attr->size = pci_resource_len(pdev, num);
> diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c
> index 3a2f90beb4cb..9bab07302bbf 100644
> --- a/drivers/pci/proc.c
> +++ b/drivers/pci/proc.c
> @@ -298,6 +298,7 @@ static int proc_bus_pci_open(struct inode *inode, struct file *file)
> fpriv->write_combine = 0;
>
> file->private_data = fpriv;
> + file->f_mapping = iomem_get_mapping();
>
> return 0;
> }
> --
> 2.30.0
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-02-10 22:21 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-04 16:58 [PATCH 0/2] pci sysfs file iomem revoke support Daniel Vetter
2021-02-04 16:58 ` [PATCH 1/2] PCI: also set up legacy files only after sysfs init Daniel Vetter
2021-02-04 21:50 ` Bjorn Helgaas
2021-02-04 22:24 ` Pali Rohár
2021-02-05 9:59 ` Daniel Vetter
2021-02-05 10:04 ` Pali Rohár
2021-02-05 10:16 ` Daniel Vetter
2021-02-05 10:21 ` Pali Rohár
2021-02-05 9:23 ` Daniel Vetter
2021-02-04 16:58 ` [PATCH 2/2] PCI: Revoke mappings like devmem Daniel Vetter
2021-02-10 22:20 ` Bjorn Helgaas [this message]
2021-03-13 21:57 ` Bjorn Helgaas
2021-03-13 22:36 ` Daniel Vetter
2021-02-07 19:43 ` [PATCH 0/2] pci sysfs file iomem revoke support Stephen Rothwell
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210210222029.GA612769@bjorn-Precision-5520 \
--to=helgaas@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=bhelgaas@google.com \
--cc=dan.j.williams@intel.com \
--cc=daniel.vetter@ffwll.ch \
--cc=daniel.vetter@intel.com \
--cc=dri-devel@lists.freedesktop.org \
--cc=gregkh@linuxfoundation.org \
--cc=jack@suse.cz \
--cc=jgg@ziepe.ca \
--cc=jglisse@redhat.com \
--cc=jhubbard@nvidia.com \
--cc=keescook@chromium.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-media@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-pci@vger.kernel.org \
--cc=linux-samsung-soc@vger.kernel.org \
--cc=sfr@canb.auug.org.au \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).