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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/include
parent5144f8a8dfd7b3681f0a2b5bf599a210b2315018 (diff)
downloadlinux-14d3b376b6c3f66d62559d457d32edf565472163.tar.gz
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/include')
-rw-r--r--arch/x86/include/asm/cpumask.h18
1 files changed, 18 insertions, 0 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 */