On Tue, Jul 31, 2018 at 10:19:35AM +0100, James Morse wrote:

Hi Bhupesh,

On 30/07/18 07:24, Bhupesh Sharma wrote:

quoted

Include KASLR offset in arm64 VMCOREINFO ELF notes to assist in
debugging. vmcore parsing in user-space already expects this value in
the notes and we are providing it for portability of those existing
tools with x86.

Ideally we would like core code to do this (so that way this
information won't be missed when an architecture adds KASLR support),
but mips has CONFIG_RANDOMIZE_BASE, and doesn't provide kaslr_offset(),
so I am not sure if this is needed for mips (and other such similar arch
cases in future). So, lets keep this architecture specific for now.

(heh, I assumed you would rewrite my train-of-thought, but I guess this works!)

quoted

As an example of a user-space use-case, consider the
makedumpfile user-space utility which will need fixup to use this
KASLR offset to work with cases where we need to find a way to
translate symbol address from vmlinux to kernel run time address
in case of KASLR boot on arm64.

Acked-by: James Morse <james.morse@arm.com>

If we want to send this to stable, it looks like it should have been part of the
KASLR series, f80fb3a3d5084 ("arm64: add support for kernel ASLR") was merged
for v4.6.
CC: <redacted> # 4.6.x

Hmm, does this warrant a stable backport? This hasn't ever worked, right?

Will