summaryrefslogtreecommitdiff
path: root/kernel
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2015-11-12 14:34:06 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-11-12 14:34:06 -0800
commit3370b69eb0c1f6a05f9051e8fc3e8768461a80f7 (patch)
tree722a75d9d3cc605bfd513752054dea1df806385d /kernel
parentbe23c9d20b341a58ad7107f9e9aa5735cea3da13 (diff)
parent370289756beccdc2a6ef9c7998fe67a7ca68bfc2 (diff)
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull second batch of kvm updates from Paolo Bonzini: "Four changes: - x86: work around two nasty cases where a benign exception occurs while another is being delivered. The endless stream of exceptions causes an infinite loop in the processor, which not even NMIs or SMIs can interrupt; in the virt case, there is no possibility to exit to the host either. - x86: support for Skylake per-guest TSC rate. Long supported by AMD, the patches mostly move things from there to common arch/x86/kvm/ code. - generic: remove local_irq_save/restore from the guest entry and exit paths when context tracking is enabled. The patches are a few months old, but we discussed them again at kernel summit. Andy will pick up from here and, in 4.5, try to remove it from the user entry/exit paths. - PPC: Two bug fixes, see merge commit 370289756becc for details" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (21 commits) KVM: x86: rename update_db_bp_intercept to update_bp_intercept KVM: svm: unconditionally intercept #DB KVM: x86: work around infinite loop in microcode when #AC is delivered context_tracking: avoid irq_save/irq_restore on guest entry and exit context_tracking: remove duplicate enabled check KVM: VMX: Dump TSC multiplier in dump_vmcs() KVM: VMX: Use a scaled host TSC for guest readings of MSR_IA32_TSC KVM: VMX: Setup TSC scaling ratio when a vcpu is loaded KVM: VMX: Enable and initialize VMX TSC scaling KVM: x86: Use the correct vcpu's TSC rate to compute time scale KVM: x86: Move TSC scaling logic out of call-back read_l1_tsc() KVM: x86: Move TSC scaling logic out of call-back adjust_tsc_offset() KVM: x86: Replace call-back compute_tsc_offset() with a common function KVM: x86: Replace call-back set_tsc_khz() with a common function KVM: x86: Add a common TSC scaling function KVM: x86: Add a common TSC scaling ratio field in kvm_vcpu_arch KVM: x86: Collect information for setting TSC scaling ratio KVM: x86: declare a few variables as __read_mostly KVM: x86: merge handle_mmio_page_fault and handle_mmio_page_fault_common KVM: PPC: Book3S HV: Don't dynamically split core when already split ...
Diffstat (limited to 'kernel')
-rw-r--r--kernel/context_tracking.c80
1 files changed, 40 insertions, 40 deletions
diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
index 0a495ab35bc7..d8560ee3bab7 100644
--- a/kernel/context_tracking.c
+++ b/kernel/context_tracking.c
@@ -58,36 +58,13 @@ static void context_tracking_recursion_exit(void)
* instructions to execute won't use any RCU read side critical section
* because this function sets RCU in extended quiescent state.
*/
-void context_tracking_enter(enum ctx_state state)
+void __context_tracking_enter(enum ctx_state state)
{
- unsigned long flags;
-
- /*
- * Repeat the user_enter() check here because some archs may be calling
- * this from asm and if no CPU needs context tracking, they shouldn't
- * go further. Repeat the check here until they support the inline static
- * key check.
- */
- if (!context_tracking_is_enabled())
- return;
-
- /*
- * Some contexts may involve an exception occuring in an irq,
- * leading to that nesting:
- * rcu_irq_enter() rcu_user_exit() rcu_user_exit() rcu_irq_exit()
- * This would mess up the dyntick_nesting count though. And rcu_irq_*()
- * helpers are enough to protect RCU uses inside the exception. So
- * just return immediately if we detect we are in an IRQ.
- */
- if (in_interrupt())
- return;
-
/* Kernel threads aren't supposed to go to userspace */
WARN_ON_ONCE(!current->mm);
- local_irq_save(flags);
if (!context_tracking_recursion_enter())
- goto out_irq_restore;
+ return;
if ( __this_cpu_read(context_tracking.state) != state) {
if (__this_cpu_read(context_tracking.active)) {
@@ -120,7 +97,27 @@ void context_tracking_enter(enum ctx_state state)
__this_cpu_write(context_tracking.state, state);
}
context_tracking_recursion_exit();
-out_irq_restore:
+}
+NOKPROBE_SYMBOL(__context_tracking_enter);
+EXPORT_SYMBOL_GPL(__context_tracking_enter);
+
+void context_tracking_enter(enum ctx_state state)
+{
+ unsigned long flags;
+
+ /*
+ * Some contexts may involve an exception occuring in an irq,
+ * leading to that nesting:
+ * rcu_irq_enter() rcu_user_exit() rcu_user_exit() rcu_irq_exit()
+ * This would mess up the dyntick_nesting count though. And rcu_irq_*()
+ * helpers are enough to protect RCU uses inside the exception. So
+ * just return immediately if we detect we are in an IRQ.
+ */
+ if (in_interrupt())
+ return;
+
+ local_irq_save(flags);
+ __context_tracking_enter(state);
local_irq_restore(flags);
}
NOKPROBE_SYMBOL(context_tracking_enter);
@@ -128,7 +125,7 @@ EXPORT_SYMBOL_GPL(context_tracking_enter);
void context_tracking_user_enter(void)
{
- context_tracking_enter(CONTEXT_USER);
+ user_enter();
}
NOKPROBE_SYMBOL(context_tracking_user_enter);
@@ -144,19 +141,10 @@ NOKPROBE_SYMBOL(context_tracking_user_enter);
* This call supports re-entrancy. This way it can be called from any exception
* handler without needing to know if we came from userspace or not.
*/
-void context_tracking_exit(enum ctx_state state)
+void __context_tracking_exit(enum ctx_state state)
{
- unsigned long flags;
-
- if (!context_tracking_is_enabled())
- return;
-
- if (in_interrupt())
- return;
-
- local_irq_save(flags);
if (!context_tracking_recursion_enter())
- goto out_irq_restore;
+ return;
if (__this_cpu_read(context_tracking.state) == state) {
if (__this_cpu_read(context_tracking.active)) {
@@ -173,7 +161,19 @@ void context_tracking_exit(enum ctx_state state)
__this_cpu_write(context_tracking.state, CONTEXT_KERNEL);
}
context_tracking_recursion_exit();
-out_irq_restore:
+}
+NOKPROBE_SYMBOL(__context_tracking_exit);
+EXPORT_SYMBOL_GPL(__context_tracking_exit);
+
+void context_tracking_exit(enum ctx_state state)
+{
+ unsigned long flags;
+
+ if (in_interrupt())
+ return;
+
+ local_irq_save(flags);
+ __context_tracking_exit(state);
local_irq_restore(flags);
}
NOKPROBE_SYMBOL(context_tracking_exit);
@@ -181,7 +181,7 @@ EXPORT_SYMBOL_GPL(context_tracking_exit);
void context_tracking_user_exit(void)
{
- context_tracking_exit(CONTEXT_USER);
+ user_exit();
}
NOKPROBE_SYMBOL(context_tracking_user_exit);