From ae749c7ab475de2c9c427058db19921c91846e89 Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Wed, 12 Apr 2017 13:25:54 +0100 Subject: 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 Signed-off-by: Bjorn Helgaas --- include/linux/pci.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux/pci.h') 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 +#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 -- cgit v1.2.3