diff options
| author |   David Woodhouse <dwmw@amazon.co.uk> | 2017-04-12 13:25:54 +0100 |
|---|---|---|
| committer |   Bjorn Helgaas <bhelgaas@google.com> | 2017-04-18 13:01:42 -0500 |
| commit | ae749c7ab475de2c9c427058db19921c91846e89 (patch) | |
| tree | 0fbb5e8de9c0827c196f5296409622beb5e9aec9 /drivers/pci/proc.c | |
| parent | xtensa/PCI: Do not mmap PCI BARs to userspace as write-through (diff) | |
| download | linux-dev-ae749c7ab475de2c9c427058db19921c91846e89.tar.xz linux-dev-ae749c7ab475de2c9c427058db19921c91846e89.zip | |
PCI: Add arch_can_pci_mmap_wc() macro
Most of the almost-identical versions of pci_mmap_page_range() silently
ignore the 'write_combine' argument and give uncached mappings.
Yet we allow the PCIIOC_WRITE_COMBINE ioctl in /proc/bus/pci, expose the
'resourceX_wc' file in sysfs, and allow an attempted mapping to apparently
succeed.
To fix this, introduce a macro arch_can_pci_mmap_wc() which indicates
whether the platform can do a write-combining mapping. On x86 this ends up
being pat_enabled(), while the few other platforms that support it can just
set it to a literal '1'.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'drivers/pci/proc.c')
| -rw-r--r-- | drivers/pci/proc.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c index dc8912e2d4a1..a2aa58a8fb96 100644 --- a/drivers/pci/proc.c +++ b/drivers/pci/proc.c @@ -210,14 +210,15 @@ static long proc_bus_pci_ioctl(struct file *file, unsigned int cmd, break; case PCIIOC_WRITE_COMBINE: - if (arg) - fpriv->write_combine = 1; - else - fpriv->write_combine = 0; - break; - + if (arch_can_pci_mmap_wc()) { + if (arg) + fpriv->write_combine = 1; + else + fpriv->write_combine = 0; + break; + } + /* If arch decided it can't, fall through... */ #endif /* HAVE_PCI_MMAP */ - default: ret = -EINVAL; break; |