| Message ID | 1415877558-8906-2-git-send-email-lorenzo.pieralisi@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
On Thu, Nov 13, 2014 at 11:19:15AM +0000, Lorenzo Pieralisi wrote: > The introduction of pci_mmap_fits() in commit: > > b5ff7df3df9efab511244d5a299fce706c71af48 > "Check mapped ranges on sysfs resource files" > > allowed to check for valid range mappings of PCI resources to user space > when mapping PCI resources through the sysfs filesystem. > > The mapping of resources through the sysfs expects the offset passed > by the user through the mmap syscall to be 0, and the pgoff is adjusted > by the kernel to memory map the resource to the CPU physical address > corresponding to the PCI resource in question. > > The usage of procfs mapping of PCI resources (/proc/bus/pci files) > is more controversial in that userspace programs mapping PCI resources > are expected to pass in the mmap offset field either a CPU physical address > or a PCI bar value, depending on the architecture. > > By the time pci_mmap_fits() was used to check PCI resource ranges for > procfs PCI resources mapping in commit: > > 9eff02e2042f96fb2aedd02e032eca1c5333d7 > "PCI: check mmap range of /proc/bus/pci files too" > > the procfs interface for mmapping resources to user space broke, since > pci_mmap_fits() expected the offset passed from user space in the mmap > call to be 0, not the CPU physical address or PCI BAR value of the > resource in question. > > Subsequent attempts at fixing the pci_mmap_fits() implementation failed > to fix the issue (or fixed the issue in some architectures but not for > all of them, ARM and SPARC procfs interface PCI resources mapping stayed > broken throughout) in particular commits: > > 8c05cd08a7504b855c265263e84af61aabafa329 > "PCI: fix offset check for sysfs mmapped files" > > and > > 3b519e4ea618b6943a82931630872907f9ac2c2b > "PCI: fix size checks for mmap() on /proc/bus/pci files" > > fixed procfs PCI resources mapping checks in pci_mmap_fits for some > architectures, but not for architectures like SPARC that expects > the offset value passed from user space through the mmap syscall > (when mapping through procfs) to represent the PCI BAR value of the > resource to be mapped. > > The reason behind the breakage is the following. The addresses stored > in PCI device resources for memory spaces correspond to CPU physical > addresses, which do not necessarily map 1:1 to PCI bus addresses as > programmed in PCI devices configuration spaces. > > This implies that the sanity checks carried out in pci_mmap_fits() to > ensure that the user executes an mmap of a "real" pci resource are > erroneous when executed through procfs. Some platforms (ie SPARC) > expect the offset value to be passed in (procfs mapping) to be the > PCI BAR configuration value as read from the PCI device configuration > space, not the fixed-up CPU physical address that is present in PCI > device resources. > > The required pgoff (offset in mmap syscall) value passed from userspace > is supposed to represent the resource value exported through > /proc/bus/pci/devices when the resource is mmapped though procfs (and 0 > when the mapping is carried out through sysfs resource files), which > corresponds to the PCI resource filtered through the pci_resource_to_user() > API. > > This patch converts the PCI resource to the expected "user visible" > value through pci_resource_to_user() before carrying out sanity checks > in pci_mmap_fits() so that the check is carried out on the resource > values as expected from the userspace mmap API. > > Cc: Arnd Bergmann <arnd@arndb.de> > Cc: Jesse Barnes <jbarnes@virtuousgeek.org> > Cc: Bjorn Helgaas <bhelgaas@google.com> > Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> > Cc: Russell King <linux@arm.linux.org.uk> > Cc: David S. Miller <davem@davemloft.net> > Cc: Michal Simek <monstr@monstr.eu> > Cc: Martin Wilck <martin.wilck@ts.fujitsu.com> > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Hi Lorenzo, I think this patch is the right thing to do. I'm going to try to write patches for microblaze, mips, powerpc, and sparc that implement their pci_resource_to_user() in terms of pcibios_resource_to_bus() (the patches are easy; it's the arguments for correctness that take time). Then I'll try to convince myself that those arches are currently broken and will be fixed by your patch below. But I'll be on vacation all next week, so this will take me some time and it may not make the next merge window. Bjorn > --- > drivers/pci/pci-sysfs.c | 13 ++++++++----- > 1 file changed, 8 insertions(+), 5 deletions(-) > > diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c > index 2c6643f..e4634e3 100644 > --- a/drivers/pci/pci-sysfs.c > +++ b/drivers/pci/pci-sysfs.c > @@ -963,17 +963,20 @@ void pci_remove_legacy_files(struct pci_bus *b) > int pci_mmap_fits(struct pci_dev *pdev, int resno, struct vm_area_struct *vma, > enum pci_mmap_api mmap_api) > { > - unsigned long nr, start, size, pci_start; > + unsigned long nr, start, size, pci_offset; > + resource_size_t pci_start, pci_end; > > if (pci_resource_len(pdev, resno) == 0) > return 0; > nr = vma_pages(vma); > start = vma->vm_pgoff; > + pci_resource_to_user(pdev, resno, &pdev->resource[resno], > + &pci_start, &pci_end); > size = ((pci_resource_len(pdev, resno) - 1) >> PAGE_SHIFT) + 1; > - pci_start = (mmap_api == PCI_MMAP_PROCFS) ? > - pci_resource_start(pdev, resno) >> PAGE_SHIFT : 0; > - if (start >= pci_start && start < pci_start + size && > - start + nr <= pci_start + size) > + pci_offset = (mmap_api == PCI_MMAP_PROCFS) ? > + pci_start >> PAGE_SHIFT : 0; > + if (start >= pci_offset && start < pci_offset + size && > + start + nr <= pci_offset + size) > return 1; > return 0; > } > -- > 2.1.2 > -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Nov 21, 2014 at 05:51:14PM +0000, Bjorn Helgaas wrote: > On Thu, Nov 13, 2014 at 11:19:15AM +0000, Lorenzo Pieralisi wrote: > > The introduction of pci_mmap_fits() in commit: > > > > b5ff7df3df9efab511244d5a299fce706c71af48 > > "Check mapped ranges on sysfs resource files" > > > > allowed to check for valid range mappings of PCI resources to user space > > when mapping PCI resources through the sysfs filesystem. > > > > The mapping of resources through the sysfs expects the offset passed > > by the user through the mmap syscall to be 0, and the pgoff is adjusted > > by the kernel to memory map the resource to the CPU physical address > > corresponding to the PCI resource in question. > > > > The usage of procfs mapping of PCI resources (/proc/bus/pci files) > > is more controversial in that userspace programs mapping PCI resources > > are expected to pass in the mmap offset field either a CPU physical address > > or a PCI bar value, depending on the architecture. > > > > By the time pci_mmap_fits() was used to check PCI resource ranges for > > procfs PCI resources mapping in commit: > > > > 9eff02e2042f96fb2aedd02e032eca1c5333d7 > > "PCI: check mmap range of /proc/bus/pci files too" > > > > the procfs interface for mmapping resources to user space broke, since > > pci_mmap_fits() expected the offset passed from user space in the mmap > > call to be 0, not the CPU physical address or PCI BAR value of the > > resource in question. > > > > Subsequent attempts at fixing the pci_mmap_fits() implementation failed > > to fix the issue (or fixed the issue in some architectures but not for > > all of them, ARM and SPARC procfs interface PCI resources mapping stayed > > broken throughout) in particular commits: > > > > 8c05cd08a7504b855c265263e84af61aabafa329 > > "PCI: fix offset check for sysfs mmapped files" > > > > and > > > > 3b519e4ea618b6943a82931630872907f9ac2c2b > > "PCI: fix size checks for mmap() on /proc/bus/pci files" > > > > fixed procfs PCI resources mapping checks in pci_mmap_fits for some > > architectures, but not for architectures like SPARC that expects > > the offset value passed from user space through the mmap syscall > > (when mapping through procfs) to represent the PCI BAR value of the > > resource to be mapped. > > > > The reason behind the breakage is the following. The addresses stored > > in PCI device resources for memory spaces correspond to CPU physical > > addresses, which do not necessarily map 1:1 to PCI bus addresses as > > programmed in PCI devices configuration spaces. > > > > This implies that the sanity checks carried out in pci_mmap_fits() to > > ensure that the user executes an mmap of a "real" pci resource are > > erroneous when executed through procfs. Some platforms (ie SPARC) > > expect the offset value to be passed in (procfs mapping) to be the > > PCI BAR configuration value as read from the PCI device configuration > > space, not the fixed-up CPU physical address that is present in PCI > > device resources. > > > > The required pgoff (offset in mmap syscall) value passed from userspace > > is supposed to represent the resource value exported through > > /proc/bus/pci/devices when the resource is mmapped though procfs (and 0 > > when the mapping is carried out through sysfs resource files), which > > corresponds to the PCI resource filtered through the pci_resource_to_user() > > API. > > > > This patch converts the PCI resource to the expected "user visible" > > value through pci_resource_to_user() before carrying out sanity checks > > in pci_mmap_fits() so that the check is carried out on the resource > > values as expected from the userspace mmap API. > > > > Cc: Arnd Bergmann <arnd@arndb.de> > > Cc: Jesse Barnes <jbarnes@virtuousgeek.org> > > Cc: Bjorn Helgaas <bhelgaas@google.com> > > Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> > > Cc: Russell King <linux@arm.linux.org.uk> > > Cc: David S. Miller <davem@davemloft.net> > > Cc: Michal Simek <monstr@monstr.eu> > > Cc: Martin Wilck <martin.wilck@ts.fujitsu.com> > > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> > > Hi Lorenzo, > > I think this patch is the right thing to do. I'm going to try to write > patches for microblaze, mips, powerpc, and sparc that implement their > pci_resource_to_user() in terms of pcibios_resource_to_bus() (the patches > are easy; it's the arguments for correctness that take time). Then I'll > try to convince myself that those arches are currently broken and will be > fixed by your patch below. I think that in doing that you might end up breaking at least powerpc and microblaze proc and sys interfaces, but I agree with the process. > But I'll be on vacation all next week, so this will take me some time and > it may not make the next merge window. I understand that, it holds back patch 2, but it is fine since it can get in as a fix even if it misses the merge window, as long as you agree with the overall approach. Thank you, Lorenzo -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, 2014-11-21 at 10:51 -0700, Bjorn Helgaas wrote: > I think this patch is the right thing to do. I'm going to try to write > patches for microblaze, mips, powerpc, and sparc that implement their > pci_resource_to_user() in terms of pcibios_resource_to_bus() (the patches > are easy; it's the arguments for correctness that take time). Then I'll > try to convince myself that those arches are currently broken and will be > fixed by your patch below. > > But I'll be on vacation all next week, so this will take me some time and > it may not make the next merge window. I do remember all sort of funky breakage in that area a long time ago but I can't quite remember the details and how I ended up with the current code :-( The one thing to keep in mind is that there was always confusion in the userspace users of the /proc interface as to what offset they had to use... the BAR value or something translated via /proc/.../resources (Normally the latter but a lot of stuff got it wrong ...) Cheers, Ben. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Bjorn, On Fri, Nov 21, 2014 at 05:51:14PM +0000, Bjorn Helgaas wrote: > On Thu, Nov 13, 2014 at 11:19:15AM +0000, Lorenzo Pieralisi wrote: > > The introduction of pci_mmap_fits() in commit: > > > > b5ff7df3df9efab511244d5a299fce706c71af48 > > "Check mapped ranges on sysfs resource files" > > > > allowed to check for valid range mappings of PCI resources to user space > > when mapping PCI resources through the sysfs filesystem. > > > > The mapping of resources through the sysfs expects the offset passed > > by the user through the mmap syscall to be 0, and the pgoff is adjusted > > by the kernel to memory map the resource to the CPU physical address > > corresponding to the PCI resource in question. > > > > The usage of procfs mapping of PCI resources (/proc/bus/pci files) > > is more controversial in that userspace programs mapping PCI resources > > are expected to pass in the mmap offset field either a CPU physical address > > or a PCI bar value, depending on the architecture. > > > > By the time pci_mmap_fits() was used to check PCI resource ranges for > > procfs PCI resources mapping in commit: > > > > 9eff02e2042f96fb2aedd02e032eca1c5333d7 > > "PCI: check mmap range of /proc/bus/pci files too" > > > > the procfs interface for mmapping resources to user space broke, since > > pci_mmap_fits() expected the offset passed from user space in the mmap > > call to be 0, not the CPU physical address or PCI BAR value of the > > resource in question. > > > > Subsequent attempts at fixing the pci_mmap_fits() implementation failed > > to fix the issue (or fixed the issue in some architectures but not for > > all of them, ARM and SPARC procfs interface PCI resources mapping stayed > > broken throughout) in particular commits: > > > > 8c05cd08a7504b855c265263e84af61aabafa329 > > "PCI: fix offset check for sysfs mmapped files" > > > > and > > > > 3b519e4ea618b6943a82931630872907f9ac2c2b > > "PCI: fix size checks for mmap() on /proc/bus/pci files" > > > > fixed procfs PCI resources mapping checks in pci_mmap_fits for some > > architectures, but not for architectures like SPARC that expects > > the offset value passed from user space through the mmap syscall > > (when mapping through procfs) to represent the PCI BAR value of the > > resource to be mapped. > > > > The reason behind the breakage is the following. The addresses stored > > in PCI device resources for memory spaces correspond to CPU physical > > addresses, which do not necessarily map 1:1 to PCI bus addresses as > > programmed in PCI devices configuration spaces. > > > > This implies that the sanity checks carried out in pci_mmap_fits() to > > ensure that the user executes an mmap of a "real" pci resource are > > erroneous when executed through procfs. Some platforms (ie SPARC) > > expect the offset value to be passed in (procfs mapping) to be the > > PCI BAR configuration value as read from the PCI device configuration > > space, not the fixed-up CPU physical address that is present in PCI > > device resources. > > > > The required pgoff (offset in mmap syscall) value passed from userspace > > is supposed to represent the resource value exported through > > /proc/bus/pci/devices when the resource is mmapped though procfs (and 0 > > when the mapping is carried out through sysfs resource files), which > > corresponds to the PCI resource filtered through the pci_resource_to_user() > > API. > > > > This patch converts the PCI resource to the expected "user visible" > > value through pci_resource_to_user() before carrying out sanity checks > > in pci_mmap_fits() so that the check is carried out on the resource > > values as expected from the userspace mmap API. > > > > Cc: Arnd Bergmann <arnd@arndb.de> > > Cc: Jesse Barnes <jbarnes@virtuousgeek.org> > > Cc: Bjorn Helgaas <bhelgaas@google.com> > > Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> > > Cc: Russell King <linux@arm.linux.org.uk> > > Cc: David S. Miller <davem@davemloft.net> > > Cc: Michal Simek <monstr@monstr.eu> > > Cc: Martin Wilck <martin.wilck@ts.fujitsu.com> > > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> > > Hi Lorenzo, > > I think this patch is the right thing to do. I'm going to try to write > patches for microblaze, mips, powerpc, and sparc that implement their > pci_resource_to_user() in terms of pcibios_resource_to_bus() (the patches > are easy; it's the arguments for correctness that take time). Then I'll > try to convince myself that those arches are currently broken and will be > fixed by your patch below. > > But I'll be on vacation all next week, so this will take me some time and > it may not make the next merge window. I do not know if you had time to implement the patches above, I would like to ask Russell to merge patch 2 of this series though, since (1) it is a fix in the first place given the current proc/sys interface, and (2) we need it to remove dependency on pcibios for arm64 drivers; I am just waiting to merge patch 2 upstream since in a way it depends on your decision on what the final proc/sys interface should look like and how we implement it. As things stand, patch 2 can be merged and fixes the current API on ARM. Thanks, Lorenzo > > Bjorn > > > --- > > drivers/pci/pci-sysfs.c | 13 ++++++++----- > > 1 file changed, 8 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c > > index 2c6643f..e4634e3 100644 > > --- a/drivers/pci/pci-sysfs.c > > +++ b/drivers/pci/pci-sysfs.c > > @@ -963,17 +963,20 @@ void pci_remove_legacy_files(struct pci_bus *b) > > int pci_mmap_fits(struct pci_dev *pdev, int resno, struct vm_area_struct *vma, > > enum pci_mmap_api mmap_api) > > { > > - unsigned long nr, start, size, pci_start; > > + unsigned long nr, start, size, pci_offset; > > + resource_size_t pci_start, pci_end; > > > > if (pci_resource_len(pdev, resno) == 0) > > return 0; > > nr = vma_pages(vma); > > start = vma->vm_pgoff; > > + pci_resource_to_user(pdev, resno, &pdev->resource[resno], > > + &pci_start, &pci_end); > > size = ((pci_resource_len(pdev, resno) - 1) >> PAGE_SHIFT) + 1; > > - pci_start = (mmap_api == PCI_MMAP_PROCFS) ? > > - pci_resource_start(pdev, resno) >> PAGE_SHIFT : 0; > > - if (start >= pci_start && start < pci_start + size && > > - start + nr <= pci_start + size) > > + pci_offset = (mmap_api == PCI_MMAP_PROCFS) ? > > + pci_start >> PAGE_SHIFT : 0; > > + if (start >= pci_offset && start < pci_offset + size && > > + start + nr <= pci_offset + size) > > return 1; > > return 0; > > } > > -- > > 2.1.2 > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Jan 21, 2015 at 06:44:56PM +0000, Lorenzo Pieralisi wrote: > Hi Bjorn, > > On Fri, Nov 21, 2014 at 05:51:14PM +0000, Bjorn Helgaas wrote: > > On Thu, Nov 13, 2014 at 11:19:15AM +0000, Lorenzo Pieralisi wrote: > > > The introduction of pci_mmap_fits() in commit: > > > > > > b5ff7df3df9efab511244d5a299fce706c71af48 > > > "Check mapped ranges on sysfs resource files" > > > > > > allowed to check for valid range mappings of PCI resources to user space > > > when mapping PCI resources through the sysfs filesystem. > > > > > > The mapping of resources through the sysfs expects the offset passed > > > by the user through the mmap syscall to be 0, and the pgoff is adjusted > > > by the kernel to memory map the resource to the CPU physical address > > > corresponding to the PCI resource in question. > > > > > > The usage of procfs mapping of PCI resources (/proc/bus/pci files) > > > is more controversial in that userspace programs mapping PCI resources > > > are expected to pass in the mmap offset field either a CPU physical address > > > or a PCI bar value, depending on the architecture. > > > > > > By the time pci_mmap_fits() was used to check PCI resource ranges for > > > procfs PCI resources mapping in commit: > > > > > > 9eff02e2042f96fb2aedd02e032eca1c5333d7 > > > "PCI: check mmap range of /proc/bus/pci files too" > > > > > > the procfs interface for mmapping resources to user space broke, since > > > pci_mmap_fits() expected the offset passed from user space in the mmap > > > call to be 0, not the CPU physical address or PCI BAR value of the > > > resource in question. > > > > > > Subsequent attempts at fixing the pci_mmap_fits() implementation failed > > > to fix the issue (or fixed the issue in some architectures but not for > > > all of them, ARM and SPARC procfs interface PCI resources mapping stayed > > > broken throughout) in particular commits: > > > > > > 8c05cd08a7504b855c265263e84af61aabafa329 > > > "PCI: fix offset check for sysfs mmapped files" > > > > > > and > > > > > > 3b519e4ea618b6943a82931630872907f9ac2c2b > > > "PCI: fix size checks for mmap() on /proc/bus/pci files" > > > > > > fixed procfs PCI resources mapping checks in pci_mmap_fits for some > > > architectures, but not for architectures like SPARC that expects > > > the offset value passed from user space through the mmap syscall > > > (when mapping through procfs) to represent the PCI BAR value of the > > > resource to be mapped. > > > > > > The reason behind the breakage is the following. The addresses stored > > > in PCI device resources for memory spaces correspond to CPU physical > > > addresses, which do not necessarily map 1:1 to PCI bus addresses as > > > programmed in PCI devices configuration spaces. > > > > > > This implies that the sanity checks carried out in pci_mmap_fits() to > > > ensure that the user executes an mmap of a "real" pci resource are > > > erroneous when executed through procfs. Some platforms (ie SPARC) > > > expect the offset value to be passed in (procfs mapping) to be the > > > PCI BAR configuration value as read from the PCI device configuration > > > space, not the fixed-up CPU physical address that is present in PCI > > > device resources. > > > > > > The required pgoff (offset in mmap syscall) value passed from userspace > > > is supposed to represent the resource value exported through > > > /proc/bus/pci/devices when the resource is mmapped though procfs (and 0 > > > when the mapping is carried out through sysfs resource files), which > > > corresponds to the PCI resource filtered through the pci_resource_to_user() > > > API. > > > > > > This patch converts the PCI resource to the expected "user visible" > > > value through pci_resource_to_user() before carrying out sanity checks > > > in pci_mmap_fits() so that the check is carried out on the resource > > > values as expected from the userspace mmap API. > > > > > > Cc: Arnd Bergmann <arnd@arndb.de> > > > Cc: Jesse Barnes <jbarnes@virtuousgeek.org> > > > Cc: Bjorn Helgaas <bhelgaas@google.com> > > > Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> > > > Cc: Russell King <linux@arm.linux.org.uk> > > > Cc: David S. Miller <davem@davemloft.net> > > > Cc: Michal Simek <monstr@monstr.eu> > > > Cc: Martin Wilck <martin.wilck@ts.fujitsu.com> > > > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> > > > > Hi Lorenzo, > > > > I think this patch is the right thing to do. I'm going to try to write > > patches for microblaze, mips, powerpc, and sparc that implement their > > pci_resource_to_user() in terms of pcibios_resource_to_bus() (the patches > > are easy; it's the arguments for correctness that take time). Then I'll > > try to convince myself that those arches are currently broken and will be > > fixed by your patch below. > > > > But I'll be on vacation all next week, so this will take me some time and > > it may not make the next merge window. > > I do not know if you had time to implement the patches above, I would > like to ask Russell to merge patch 2 of this series though, since (1) it > is a fix in the first place given the current proc/sys interface, and > (2) we need it to remove dependency on pcibios for arm64 drivers; I am > just waiting to merge patch 2 upstream since in a way it depends on your > decision on what the final proc/sys interface should look like and how > we implement it. > > As things stand, patch 2 can be merged and fixes the current API on ARM. I haven't had a chance to do anything with these, sorry. The second patch only touches ARM, and I think it's fine to merge that. I'll ack it in case that's useful to you. Bjorn > > > --- > > > drivers/pci/pci-sysfs.c | 13 ++++++++----- > > > 1 file changed, 8 insertions(+), 5 deletions(-) > > > > > > diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c > > > index 2c6643f..e4634e3 100644 > > > --- a/drivers/pci/pci-sysfs.c > > > +++ b/drivers/pci/pci-sysfs.c > > > @@ -963,17 +963,20 @@ void pci_remove_legacy_files(struct pci_bus *b) > > > int pci_mmap_fits(struct pci_dev *pdev, int resno, struct vm_area_struct *vma, > > > enum pci_mmap_api mmap_api) > > > { > > > - unsigned long nr, start, size, pci_start; > > > + unsigned long nr, start, size, pci_offset; > > > + resource_size_t pci_start, pci_end; > > > > > > if (pci_resource_len(pdev, resno) == 0) > > > return 0; > > > nr = vma_pages(vma); > > > start = vma->vm_pgoff; > > > + pci_resource_to_user(pdev, resno, &pdev->resource[resno], > > > + &pci_start, &pci_end); > > > size = ((pci_resource_len(pdev, resno) - 1) >> PAGE_SHIFT) + 1; > > > - pci_start = (mmap_api == PCI_MMAP_PROCFS) ? > > > - pci_resource_start(pdev, resno) >> PAGE_SHIFT : 0; > > > - if (start >= pci_start && start < pci_start + size && > > > - start + nr <= pci_start + size) > > > + pci_offset = (mmap_api == PCI_MMAP_PROCFS) ? > > > + pci_start >> PAGE_SHIFT : 0; > > > + if (start >= pci_offset && start < pci_offset + size && > > > + start + nr <= pci_offset + size) > > > return 1; > > > return 0; > > > } > > > -- > > > 2.1.2 > > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > Please read the FAQ at http://www.tux.org/lkml/ > > -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 2c6643f..e4634e3 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -963,17 +963,20 @@ void pci_remove_legacy_files(struct pci_bus *b) int pci_mmap_fits(struct pci_dev *pdev, int resno, struct vm_area_struct *vma, enum pci_mmap_api mmap_api) { - unsigned long nr, start, size, pci_start; + unsigned long nr, start, size, pci_offset; + resource_size_t pci_start, pci_end; if (pci_resource_len(pdev, resno) == 0) return 0; nr = vma_pages(vma); start = vma->vm_pgoff; + pci_resource_to_user(pdev, resno, &pdev->resource[resno], + &pci_start, &pci_end); size = ((pci_resource_len(pdev, resno) - 1) >> PAGE_SHIFT) + 1; - pci_start = (mmap_api == PCI_MMAP_PROCFS) ? - pci_resource_start(pdev, resno) >> PAGE_SHIFT : 0; - if (start >= pci_start && start < pci_start + size && - start + nr <= pci_start + size) + pci_offset = (mmap_api == PCI_MMAP_PROCFS) ? + pci_start >> PAGE_SHIFT : 0; + if (start >= pci_offset && start < pci_offset + size && + start + nr <= pci_offset + size) return 1; return 0; }
The introduction of pci_mmap_fits() in commit: b5ff7df3df9efab511244d5a299fce706c71af48 "Check mapped ranges on sysfs resource files" allowed to check for valid range mappings of PCI resources to user space when mapping PCI resources through the sysfs filesystem. The mapping of resources through the sysfs expects the offset passed by the user through the mmap syscall to be 0, and the pgoff is adjusted by the kernel to memory map the resource to the CPU physical address corresponding to the PCI resource in question. The usage of procfs mapping of PCI resources (/proc/bus/pci files) is more controversial in that userspace programs mapping PCI resources are expected to pass in the mmap offset field either a CPU physical address or a PCI bar value, depending on the architecture. By the time pci_mmap_fits() was used to check PCI resource ranges for procfs PCI resources mapping in commit: 9eff02e2042f96fb2aedd02e032eca1c5333d7 "PCI: check mmap range of /proc/bus/pci files too" the procfs interface for mmapping resources to user space broke, since pci_mmap_fits() expected the offset passed from user space in the mmap call to be 0, not the CPU physical address or PCI BAR value of the resource in question. Subsequent attempts at fixing the pci_mmap_fits() implementation failed to fix the issue (or fixed the issue in some architectures but not for all of them, ARM and SPARC procfs interface PCI resources mapping stayed broken throughout) in particular commits: 8c05cd08a7504b855c265263e84af61aabafa329 "PCI: fix offset check for sysfs mmapped files" and 3b519e4ea618b6943a82931630872907f9ac2c2b "PCI: fix size checks for mmap() on /proc/bus/pci files" fixed procfs PCI resources mapping checks in pci_mmap_fits for some architectures, but not for architectures like SPARC that expects the offset value passed from user space through the mmap syscall (when mapping through procfs) to represent the PCI BAR value of the resource to be mapped. The reason behind the breakage is the following. The addresses stored in PCI device resources for memory spaces correspond to CPU physical addresses, which do not necessarily map 1:1 to PCI bus addresses as programmed in PCI devices configuration spaces. This implies that the sanity checks carried out in pci_mmap_fits() to ensure that the user executes an mmap of a "real" pci resource are erroneous when executed through procfs. Some platforms (ie SPARC) expect the offset value to be passed in (procfs mapping) to be the PCI BAR configuration value as read from the PCI device configuration space, not the fixed-up CPU physical address that is present in PCI device resources. The required pgoff (offset in mmap syscall) value passed from userspace is supposed to represent the resource value exported through /proc/bus/pci/devices when the resource is mmapped though procfs (and 0 when the mapping is carried out through sysfs resource files), which corresponds to the PCI resource filtered through the pci_resource_to_user() API. This patch converts the PCI resource to the expected "user visible" value through pci_resource_to_user() before carrying out sanity checks in pci_mmap_fits() so that the check is carried out on the resource values as expected from the userspace mmap API. Cc: Arnd Bergmann <arnd@arndb.de> Cc: Jesse Barnes <jbarnes@virtuousgeek.org> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: David S. Miller <davem@davemloft.net> Cc: Michal Simek <monstr@monstr.eu> Cc: Martin Wilck <martin.wilck@ts.fujitsu.com> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> --- drivers/pci/pci-sysfs.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)