summaryrefslogtreecommitdiff
path: root/arch
diff options
context:
space:
mode:
authorThomas Gleixner <tglx@linutronix.de>2018-11-25 19:33:39 +0100
committerThomas Gleixner <tglx@linutronix.de>2018-11-28 11:57:07 +0100
commita74cfffb03b73d41e08f84c2e5c87dec0ce3db9f (patch)
tree8cb909ef80da758be3f533dd877cd3585a609941 /arch
parent321a874a7ef85655e93b3206d0f36b4a6097f948 (diff)
x86/speculation: Rework SMT state change
arch_smt_update() is only called when the sysfs SMT control knob is changed. This means that when SMT is enabled in the sysfs control knob the system is considered to have SMT active even if all siblings are offline. To allow finegrained control of the speculation mitigations, the actual SMT state is more interesting than the fact that siblings could be enabled. Rework the code, so arch_smt_update() is invoked from each individual CPU hotplug function, and simplify the update function while at it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Woodhouse <dwmw@amazon.co.uk> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Casey Schaufler <casey.schaufler@intel.com> Cc: Asit Mallick <asit.k.mallick@intel.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Jon Masters <jcm@redhat.com> Cc: Waiman Long <longman9394@gmail.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Dave Stewart <david.c.stewart@intel.com> Cc: Kees Cook <keescook@chromium.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20181125185004.521974984@linutronix.de
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/cpu/bugs.c11
1 files changed, 5 insertions, 6 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index a723af0c4400..5625b323ff32 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -14,6 +14,7 @@
#include <linux/module.h>
#include <linux/nospec.h>
#include <linux/prctl.h>
+#include <linux/sched/smt.h>
#include <asm/spec-ctrl.h>
#include <asm/cmdline.h>
@@ -344,16 +345,14 @@ void arch_smt_update(void)
return;
mutex_lock(&spec_ctrl_mutex);
- mask = x86_spec_ctrl_base;
- if (cpu_smt_control == CPU_SMT_ENABLED)
+
+ mask = x86_spec_ctrl_base & ~SPEC_CTRL_STIBP;
+ if (sched_smt_active())
mask |= SPEC_CTRL_STIBP;
- else
- mask &= ~SPEC_CTRL_STIBP;
if (mask != x86_spec_ctrl_base) {
pr_info("Spectre v2 cross-process SMT mitigation: %s STIBP\n",
- cpu_smt_control == CPU_SMT_ENABLED ?
- "Enabling" : "Disabling");
+ mask & SPEC_CTRL_STIBP ? "Enabling" : "Disabling");
x86_spec_ctrl_base = mask;
on_each_cpu(update_stibp_msr, NULL, 1);
}