Commit 14d3b376 authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

x86/entry, cpumask: Provide non-instrumented variant of cpu_is_offline() 



vmlinux.o: warning: objtool: exc_nmi()+0x12: call to cpumask_test_cpu.constprop.0() leaves .noinstr.text section
vmlinux.o: warning: objtool: mce_check_crashing_cpu()+0x12: call to cpumask_test_cpu.constprop.0()leaves .noinstr.text section

  cpumask_test_cpu()
    test_bit()
      instrument_atomic_read()
      arch_test_bit()

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
parent 5144f8a8

arch/x86/include/asm/cpumask.h

+18 −0
Original line number Diff line number Diff line
@@ -11,5 +11,23 @@ extern cpumask_var_t cpu_sibling_setup_mask; 


extern void setup_cpu_local_masks(void);



/*

 * NMI and MCE exceptions need cpu_is_offline() _really_ early,

 * provide an arch_ special for them to avoid instrumentation.

 */

#if NR_CPUS > 1

static __always_inline bool arch_cpu_online(int cpu)

{

	return arch_test_bit(cpu, cpumask_bits(cpu_online_mask));

}

#else

static __always_inline bool arch_cpu_online(int cpu)

{

	return cpu == 0;

}

#endif



#define arch_cpu_is_offline(cpu)	unlikely(!arch_cpu_online(cpu))



#endif /* __ASSEMBLY__ */

#endif /* _ASM_X86_CPUMASK_H */

arch/x86/kernel/cpu/mce/core.c

+1 −1
Original line number Diff line number Diff line
@@ -1083,7 +1083,7 @@ static noinstr bool mce_check_crashing_cpu(void) 
{

	unsigned int cpu = smp_processor_id();



	if (cpu_is_offline(cpu) ||

	if (arch_cpu_is_offline(cpu) ||

	    (crashing_cpu != -1 && crashing_cpu != cpu)) {

		u64 mcgstatus;

arch/x86/kernel/nmi.c

+1 −1
Original line number Diff line number Diff line
@@ -478,7 +478,7 @@ static DEFINE_PER_CPU(unsigned long, nmi_dr7); 


DEFINE_IDTENTRY_RAW(exc_nmi)

{

	if (IS_ENABLED(CONFIG_SMP) && cpu_is_offline(smp_processor_id()))

	if (IS_ENABLED(CONFIG_SMP) && arch_cpu_is_offline(smp_processor_id()))

		return;



	if (this_cpu_read(nmi_state) != NMI_NOT_RUNNING) {

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