• Russell King's avatar
    ARM: entry: provide uaccess assembly macro hooks · 2190fed6
    Russell King authored
    Provide hooks into the kernel entry and exit paths to permit control
    of userspace visibility to the kernel.  The intended use is:
    - on entry to kernel from user, uaccess_disable will be called to
      disable userspace visibility
    - on exit from kernel to user, uaccess_enable will be called to
      enable userspace visibility
    - on entry from a kernel exception, uaccess_save_and_disable will be
      called to save the current userspace visibility setting, and disable
    - on exit from a kernel exception, uaccess_restore will be called to
      restore the userspace visibility as it was before the exception
    These hooks allows us to keep userspace visibility disabled for the
    vast majority of the kernel, except for localised regions where we
    want to explicitly access userspace.
    Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
entry-common.S 9.08 KB