From 3c2e2e6816930e25c755f2e4fc298a0d05d223cf Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 4 Apr 2017 16:54:21 +0100 Subject: [PATCH] Annotate hardware config module parameters in arch/x86/mm/ 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/. [Note: With respect to testmmiotrace, an additional patch will be added separately that makes the module refuse to load if the kernel is locked down.] Suggested-by: Alan Cox Signed-off-by: David Howells Acked-by: Steven Rostedt cc: Ingo Molnar cc: Thomas Gleixner cc: "H. Peter Anvin" cc: x86@kernel.org cc: linux-kernel@vger.kernel.org cc: nouveau@lists.freedesktop.org --- 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 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).");