linux/kernel
Josh Poimboeuf 98af845294 cpu/speculation: Add 'mitigations=' cmdline option
Keeping track of the number of mitigations for all the CPU speculation
bugs has become overwhelming for many users.  It's getting more and more
complicated to decide which mitigations are needed for a given
architecture.  Complicating matters is the fact that each arch tends to
have its own custom way to mitigate the same vulnerability.

Most users fall into a few basic categories:

a) they want all mitigations off;

b) they want all reasonable mitigations on, with SMT enabled even if
   it's vulnerable; or

c) they want all reasonable mitigations on, with SMT disabled if
   vulnerable.

Define a set of curated, arch-independent options, each of which is an
aggregation of existing options:

- mitigations=off: Disable all mitigations.

- mitigations=auto: [default] Enable all the default mitigations, but
  leave SMT enabled, even if it's vulnerable.

- mitigations=auto,nosmt: Enable all the default mitigations, disabling
  SMT if needed by a mitigation.

Currently, these options are placeholders which don't actually do
anything.  They will be fleshed out in upcoming patches.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Jiri Kosina <jkosina@suse.cz> (on x86)
Reviewed-by: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Jon Masters <jcm@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-arch@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Tyler Hicks <tyhicks@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Phil Auld <pauld@redhat.com>
Link: https://lkml.kernel.org/r/b07a8ef9b7c5055c3a4637c87d07c296d5016fe0.1555085500.git.jpoimboe@redhat.com
2019-04-17 21:37:28 +02:00
..
bpf bpf: fix sanitation rewrite in case of non-pointers 2019-03-01 21:24:08 -08:00
cgroup Merge branch 'for-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2018-12-29 10:57:20 -08:00
configs
debug kdb: use bool for binary state indicators 2018-12-30 08:31:52 +00:00
dma swiotlb: clear io_tlb_start and io_tlb_end in swiotlb_exit 2019-01-16 09:59:17 -05:00
events perf/core: Fix impossible ring-buffer sizes warning 2019-02-13 08:05:02 +01:00
gcov
irq genirq/irqdesc: Fix double increment in alloc_descs() 2019-01-18 00:43:09 +01:00
livepatch
locking futex: Handle early deadlock return correctly 2019-02-08 13:00:36 +01:00
power
printk Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
rcu
sched psi: avoid divide-by-zero crash inside virtual machines 2019-02-21 09:01:00 -08:00
time posix-cpu-timers: Unbreak timer rearming 2019-01-15 16:34:37 +01:00
trace Two more tracing fixes 2019-02-18 09:40:16 -08:00
.gitignore
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
Makefile kbuild: change filechk to surround the given command with { } 2019-01-06 09:46:51 +09:00
acct.c
async.c
audit.c
audit.h
audit_fsnotify.c
audit_tree.c
audit_watch.c
auditfilter.c
auditsc.c
backtracetest.c
bounds.c
capability.c
compat.c make 'user_access_begin()' do 'access_ok()' 2019-01-04 12:56:09 -08:00
configs.c
context_tracking.c
cpu.c cpu/speculation: Add 'mitigations=' cmdline option 2019-04-17 21:37:28 +02:00
cpu_pm.c
crash_core.c
crash_dump.c
cred.c
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c kernel/exit.c: release ptraced tasks before zap_pid_ns_processes 2019-02-01 15:46:23 -08:00
extable.c
fail_function.c
fork.c Merge branch 'akpm' (patches from Andrew) 2019-01-08 18:58:29 -08:00
freezer.c
futex.c futex: Handle early deadlock return correctly 2019-02-08 13:00:36 +01:00
groups.c
hung_task.c kernel/hung_task.c: break RCU locks based on jiffies 2019-01-04 13:13:45 -08:00
iomem.c
irq_work.c
jump_label.c jump_label: move 'asm goto' support test to Kconfig 2019-01-06 09:46:51 +09:00
kallsyms.c
kcmp.c
kcov.c kernel/kcov.c: mark write_comp_data() as notrace 2019-01-04 13:13:47 -08:00
kexec.c
kexec_core.c
kexec_file.c
kexec_internal.h
kmod.c
kprobes.c
ksysfs.c
kthread.c
latencytop.c
memremap.c
module-internal.h
module.c jump_label: move 'asm goto' support test to Kconfig 2019-01-06 09:46:51 +09:00
module_signing.c
notifier.c
nsproxy.c
padata.c
panic.c kernel/sysctl: add panic_print into sysctl 2019-01-04 13:13:47 -08:00
params.c
pid.c
pid_namespace.c
profile.c
ptrace.c Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
range.c
reboot.c
relay.c relay: check return of create_buf_file() properly 2019-01-31 14:01:48 +01:00
resource.c
rseq.c Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
seccomp.c seccomp: fix UAF in user-trap code 2019-01-15 09:43:12 -08:00
signal.c signal: Restore the stop PTRACE_EVENT_EXIT 2019-02-13 08:31:41 -06:00
smp.c cpu/hotplug: Fix "SMT disabled by BIOS" detection for KVM 2019-01-30 19:27:00 +01:00
smpboot.c
smpboot.h
softirq.c
stackleak.c
stacktrace.c
stop_machine.c
sys.c kernel/sys.c: Clarify that UNAME26 does not generate unique versions anymore 2019-01-14 10:38:03 +12:00
sys_ni.c
sysctl.c kernel/sysctl: add panic_print into sysctl 2019-01-04 13:13:47 -08:00
sysctl_binary.c kernel/sysctl: add panic_print into sysctl 2019-01-04 13:13:47 -08:00
task_work.c
taskstats.c
test_kprobes.c
torture.c
tracepoint.c
tsacct.c
ucount.c
uid16.c
uid16.h
umh.c umh: add exit routine for UMH process 2019-01-11 18:05:40 -08:00
up.c
user-return-notifier.c
user.c
user_namespace.c
utsname.c
utsname_sysctl.c
watchdog.c
watchdog_hld.c
workqueue.c psi: fix aggregation idle shut-off 2019-02-01 15:46:23 -08:00
workqueue_internal.h psi: fix aggregation idle shut-off 2019-02-01 15:46:23 -08:00