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| 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 /include/linux/pci.h | |
| parent | 03a064b431eb5cb0a91012699ac1e4d6302b327d (diff) | |
| download | lwn-ae749c7ab475de2c9c427058db19921c91846e89.tar.gz lwn-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 'include/linux/pci.h')
| -rw-r--r-- | include/linux/pci.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/pci.h b/include/linux/pci.h index eb3da1a04e6c..e614fb42d8bb 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1626,6 +1626,10 @@ static inline int pci_get_new_domain_nr(void) { return -ENOSYS; } #include <asm/pci.h> +#ifndef arch_can_pci_mmap_wc +#define arch_can_pci_mmap_wc() 0 +#endif + #ifndef pci_root_bus_fwnode #define pci_root_bus_fwnode(bus) NULL #endif |