diff options
| author | Hugh Dickins <hughd@google.com> | 2017-09-13 14:03:10 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-01-05 15:44:23 +0100 |
| commit | d94df20135ccfdfb77b1479c501564e9b4ab5bc9 (patch) | |
| tree | 8d6d20d1e0fd0046a10cafbb41df5f228d2d4916 /security | |
| parent | 9b94cf97f42ca30fe9b5010900fa6e1d6855a9f6 (diff) | |
kaiser: KAISER depends on SMP
It is absurd that KAISER should depend on SMP, but apparently nobody
has tried a UP build before: which breaks on implicit declaration of
function 'per_cpu_offset' in arch/x86/mm/kaiser.c.
Now, you would expect that to be trivially fixed up; but looking at
the System.map when that block is #ifdef'ed out of kaiser_init(),
I see that in a UP build __per_cpu_user_mapped_end is precisely at
__per_cpu_user_mapped_start, and the items carefully gathered into
that section for user-mapping on SMP, dispersed elsewhere on UP.
So, some other kind of section assignment will be needed on UP,
but implementing that is not a priority: just make KAISER depend
on SMP for now.
Also inserted a blank line before the option, tidied up the
brief Kconfig help message, and added an "If unsure, Y".
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'security')
| -rw-r--r-- | security/Kconfig | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/security/Kconfig b/security/Kconfig index 45cdb0098f38..0d54e3cc4586 100644 --- a/security/Kconfig +++ b/security/Kconfig @@ -30,14 +30,16 @@ config SECURITY model will be used. If you are unsure how to answer this question, answer N. + config KAISER bool "Remove the kernel mapping in user mode" default y - depends on X86_64 - depends on !PARAVIRT + depends on X86_64 && SMP && !PARAVIRT help - This enforces a strict kernel and user space isolation in order to close - hardware side channels on kernel address information. + This enforces a strict kernel and user space isolation, in order + to close hardware side channels on kernel address information. + + If you are unsure how to answer this question, answer Y. config KAISER_REAL_SWITCH bool "KAISER: actually switch page tables" |