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authorDavid Howells <dhowells@redhat.com>2017-04-04 18:54:29 +0300
committerDavid Howells <dhowells@redhat.com>2017-04-20 14:02:32 +0300
commit3b60daf86b133f0b15e3eb9b767c6c1752af2bd6 (patch)
treee44fce87a67db71f6d2033b252371eafac168c75 /Documentation/circular-buffers.txt
parentea38fd72fb5f065e3f655d388193db3476820482 (diff)
downloadlinux-3b60daf86b133f0b15e3eb9b767c6c1752af2bd6.tar.xz
Annotate hardware config module parameters in drivers/tty/
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 drivers/tty/. Suggested-by: Alan Cox <gnomes@lxorguk.ukuu.org.uk> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> cc: Jiri Slaby <jslaby@suse.com> cc: linux-serial@vger.kernel.org
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