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authorPeter Zijlstra <peterz@infradead.org>2020-06-03 13:32:48 +0200
committerPeter Zijlstra <peterz@infradead.org>2020-06-15 14:10:09 +0200
commit14d3b376b6c3f66d62559d457d32edf565472163 (patch)
tree0978931489a631b4fbf43cacad276d66642f113c /arch/x86
parent5144f8a8dfd7b3681f0a2b5bf599a210b2315018 (diff)
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>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/include/asm/cpumask.h18
-rw-r--r--arch/x86/kernel/cpu/mce/core.c2
-rw-r--r--arch/x86/kernel/nmi.c2
3 files changed, 20 insertions, 2 deletions
diff --git a/arch/x86/include/asm/cpumask.h b/arch/x86/include/asm/cpumask.h
index 6722ffcef2e6..3afa990d756b 100644
--- a/arch/x86/include/asm/cpumask.h
+++ b/arch/x86/include/asm/cpumask.h
@@ -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 */
diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index ce9120c4f740..fbe89a92ff36 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -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;
diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index 2de365f15684..d7c5e44b26f7 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -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) {