cpuidle, intel_idle: Fix CPUIDLE_FLAG_IBRS

objtool to the rescue:

vmlinux.o: warning: objtool: intel_idle_ibrs+0x17: call to spec_ctrl_current() leaves .noinstr.text section
vmlinux.o: warning: objtool: intel_idle_ibrs+0x27: call to wrmsrl.constprop.0() leaves .noinstr.text section

Signed-off-by: Peter Zijlstra (Intel) <[e-mail]>
Signed-off-by: Ingo Molnar <[e-mail]>
Tested-by: Tony Lindgren <[e-mail]>
Tested-by: Ulf Hansson <[e-mail]>
Acked-by: Rafael J. Wysocki <[e-mail]>
Acked-by: Frederic Weisbecker <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

arch/x86/kernel/cpu/bugs.c

···
 		wrmsrl(MSR_IA32_SPEC_CTRL, val);
 }
 
-u64 spec_ctrl_current(void)
+noinstr u64 spec_ctrl_current(void)
 {
 	return this_cpu_read(x86_spec_ctrl_current);
 }

drivers/idle/intel_idle.c

···
 	int ret;
 
 	if (smt_active)
-		wrmsrl(MSR_IA32_SPEC_CTRL, 0);
+		native_wrmsrl(MSR_IA32_SPEC_CTRL, 0);
 
 	ret = __intel_idle(dev, drv, index);
 
 	if (smt_active)
-		wrmsrl(MSR_IA32_SPEC_CTRL, spec_ctrl);
+		native_wrmsrl(MSR_IA32_SPEC_CTRL, spec_ctrl);
 
 	return ret;
 }