• Arjan van de Ven's avatar
    resource: allow MMIO exclusivity for device drivers · e8de1481
    Arjan van de Ven authored
    Device drivers that use pci_request_regions() (and similar APIs) have a
    reasonable expectation that they are the only ones accessing their device.
    As part of the e1000e hunt, we were afraid that some userland (X or some
    bootsplash stuff) was mapping the MMIO region that the driver thought it
    had exclusively via /dev/mem or via various sysfs resource mappings.
    
    This patch adds the option for device drivers to cause their reserved
    regions to the "banned from /dev/mem use" list, so now both kernel memory
    and device-exclusive MMIO regions are banned.
    NOTE: This is only active when CONFIG_STRICT_DEVMEM is set.
    
    In addition to the config option, a kernel parameter iomem=relaxed is
    provided for the cases where developers want to diagnose, in the field,
    drivers issues from userspace.
    Reviewed-by: default avatarMatthew Wilcox <willy@linux.intel.com>
    Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
    Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
    e8de1481
kernel-parameters.txt 77.5 KB