From: Peter Zijlstra <peterz@infradead.org>
To: tglx@linutronix.de
Cc: x86@kernel.org, elver@google.com, paulmck@kernel.org,
kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org,
peterz@infradead.org, will@kernel.org, dvyukov@google.com,
glider@google.com, andreyknvl@google.com
Subject: [PATCH 6/8] x86/entry, cpumask: Provide non-instrumented variant of cpu_is_offline()
Date: Thu, 04 Jun 2020 12:22:47 +0200 [thread overview]
Message-ID: <20200604102428.250420698@infradead.org> (raw)
In-Reply-To: 20200604102241.466509982@infradead.org
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>
---
arch/x86/include/asm/cpumask.h | 18 ++++++++++++++++++
arch/x86/kernel/cpu/mce/core.c | 2 +-
arch/x86/kernel/nmi.c | 2 +-
3 files changed, 20 insertions(+), 2 deletions(-)
--- 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_m
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 */
--- 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_c
{
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;
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -478,7 +478,7 @@ static DEFINE_PER_CPU(unsigned long, nmi
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) {
next prev parent reply other threads:[~2020-06-04 10:25 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-04 10:22 [PATCH 0/8] x86/entry: KCSAN/KASAN/UBSAN vs noinstr Peter Zijlstra
2020-06-04 10:22 ` [PATCH 1/8] x86, kcsan: Remove __no_kcsan_or_inline usage Peter Zijlstra
2020-06-04 10:22 ` [PATCH 2/8] kcsan: Remove __no_kcsan_or_inline Peter Zijlstra
2020-06-04 10:22 ` [PATCH 3/8] x86, kcsan: Add __no_kcsan to noinstr Peter Zijlstra
2020-06-04 10:22 ` [PATCH 4/8] kasan: Bump required compiler version Peter Zijlstra
2020-06-04 10:22 ` [PATCH 5/8] compiler_types.h: Add __no_sanitize_{address,undefined} to noinstr Peter Zijlstra
2020-06-04 10:22 ` Peter Zijlstra [this message]
2020-06-04 10:22 ` [PATCH 7/8] x86/entry, ubsan, objtool: Whitelist __ubsan_handle_*() Peter Zijlstra
2020-06-04 10:22 ` [PATCH 8/8] x86/entry, bug: Comment the instrumentation_begin() usage for WARN() Peter Zijlstra
2020-06-04 11:01 ` [PATCH 0/8] x86/entry: KCSAN/KASAN/UBSAN vs noinstr Marco Elver
2020-06-15 10:07 ` Marco Elver
2020-06-15 14:57 ` Qian Cai
2020-06-15 15:06 ` Peter Zijlstra
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