diff options
| author | Peter Zijlstra | 2022-10-27 14:54:41 -0700 |
|---|---|---|
| committer | Dave Hansen | 2022-12-15 10:37:26 -0800 |
| commit | 97e3d26b5e5f371b3ee223d94dd123e6c442ba80 (patch) | |
| tree | 80ee0994078b5307c6edd071d36574313c995243 /Documentation/RCU | |
| parent | 3f148f3318140035e87decc1214795ff0755757b (diff) | |
x86/mm: Randomize per-cpu entry area
Seth found that the CPU-entry-area; the piece of per-cpu data that is
mapped into the userspace page-tables for kPTI is not subject to any
randomization -- irrespective of kASLR settings.
On x86_64 a whole P4D (512 GB) of virtual address space is reserved for
this structure, which is plenty large enough to randomize things a
little.
As such, use a straight forward randomization scheme that avoids
duplicates to spread the existing CPUs over the available space.
[ bp: Fix le build. ]
Reported-by: Seth Jenkins <sethjenkins@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Diffstat (limited to 'Documentation/RCU')
0 files changed, 0 insertions, 0 deletions