On Wed, 05 Apr 2017 17:57:08 +0100 David Howells <[email protected]> wrote:
> When the kernel is running in secure boot mode, we lock down the kernel to > prevent userspace from modifying the running kernel image. Whilst this > includes prohibiting access to things like /dev/mem, it must also prevent > access by means of configuring driver modules in such a way as to cause a > device to access or modify the kernel image. > > To this end, annotate module_param* statements that refer to hardware > configuration and indicate for future reference what type of parameter they > specify. The parameter parser in the core sees this information and can > skip such parameters with an error message if the kernel is locked down. > The module initialisation then runs as normal, but just sees whatever the > default values for those parameters is. > > Note that we do still need to do the module initialisation because some > drivers have viable defaults set in case parameters aren't specified and > some drivers support automatic configuration (e.g. PNP or PCI) in addition > to manually coded parameters. > > This patch annotates drivers in arch/x86/mm/. > > Suggested-by: Alan Cox <[email protected]> > Signed-off-by: David Howells <[email protected]> Acked-by: Steven Rostedt (VMware) <[email protected]> -- Steve > cc: Ingo Molnar <[email protected]> > cc: Thomas Gleixner <[email protected]> > cc: "H. Peter Anvin" <[email protected]> > cc: [email protected] > cc: [email protected] > cc: [email protected] > --- > > arch/x86/mm/testmmiotrace.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/mm/testmmiotrace.c b/arch/x86/mm/testmmiotrace.c > index 38868adf07ea..f6ae6830b341 100644 > --- a/arch/x86/mm/testmmiotrace.c > +++ b/arch/x86/mm/testmmiotrace.c > @@ -9,7 +9,7 @@ > #include <linux/mmiotrace.h> > > static unsigned long mmio_address; > -module_param(mmio_address, ulong, 0); > +module_param_hw(mmio_address, ulong, iomem, 0); > MODULE_PARM_DESC(mmio_address, " Start address of the mapping of 16 kB " > "(or 8 MB if read_far is non-zero)."); >
