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Subject[tip: x86/entry] x86/entry, cpumask: Provide non-instrumented variant of cpu_is_offline()
The following commit has been merged into the x86/entry branch of tip:

Commit-ID: 02da62886d81c6683fbd6a09aec02b2c050d5827
Gitweb: https://git.kernel.org/tip/02da62886d81c6683fbd6a09aec02b2c050d5827
Author: Peter Zijlstra <peterz@infradead.org>
AuthorDate: Wed, 03 Jun 2020 13:40:23 +02:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Wed, 03 Jun 2020 16:35:39 +02:00

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: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200603114052.300804240@infradead.org

---
arch/x86/kernel/cpu/mce/core.c | 2 +-
arch/x86/kernel/nmi.c | 2 +-
include/linux/cpumask.h | 15 ++++++++++++++-
3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index b9cb381..310c2b3 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -1104,7 +1104,7 @@ 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;

diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index 4a43934..8bd5dfd 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -482,7 +482,7 @@ static DEFINE_PER_CPU(unsigned long, nmi_dr7);

DEFINE_IDTENTRY_NMI(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) {
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index f0d895d..d0f0e34 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -888,7 +888,20 @@ static inline const struct cpumask *get_cpu_mask(unsigned int cpu)
return to_cpumask(p);
}

-#define cpu_is_offline(cpu) unlikely(!cpu_online(cpu))
+#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))
+#define cpu_is_offline(cpu) unlikely(!cpu_online(cpu))

#if NR_CPUS <= BITS_PER_LONG
#define CPU_BITS_ALL \
\
 
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