Re: [PATCH v7] x86: fix kaslr and memmap collision

From: Thomas Gleixner
Date: Wed Jan 25 2017 - 05:48:11 EST

On Wed, 11 Jan 2017, Dave Jiang wrote:

> CONFIG_RANDOMIZE_BASE relocates the kernel to a random base address.
> However it does not take into account the memmap= parameter passed in from
> the kernel cmdline. This results in the kernel sometimes being put in
> the middle of memmap. Teaching kaslr to not insert the kernel in
> memmap defined regions. We will support up to 4 memmap regions. Any
> additional regions will cause kaslr to disable. The mem_avoid set has
> been augmented to add up to 4 unusable regions of memmaps provided by the
> user to exclude those regions from the set of valid address range to insert
> the uncompressed kernel image. The nn@ss ranges will be skipped by the
> mem_avoid set since it indicates memory useable.
> Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
> Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>
> Acked-by: Baoquan He <bhe@xxxxxxxxxx>

Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>