From: Hendrik Brueckner <brueckner@linux.ibm.com>
Date: Wed, 8 Aug 2018 10:30:37 +0200
Subject: s390/cpum_cf: introduce kernel_cpumcf_alert() to obtain measurement
alerts
Git-commit: 26b8317f51a20c1e4f61fbd2cc68975faad10b02
Patch-mainline: v5.1-rc1
References: jsc#SLE-6904 FATE#327581
During a __kernel_cpumcf_begin()/end() session, save measurement alerts
for the counter facility in the per-CPU cpu_cf_events variable.
Users can obtain and, optionally, clear the alerts by calling
kernel_cpumcf_alert() to specifically handle alerts.
Signed-off-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
arch/s390/include/asm/cpu_mcf.h | 2 ++
arch/s390/kernel/perf_cpum_cf.c | 18 ++++++++++++++++++
2 files changed, 20 insertions(+)
--- a/arch/s390/include/asm/cpu_mcf.h
+++ b/arch/s390/include/asm/cpu_mcf.h
@@ -52,6 +52,7 @@ static inline void ctr_set_stop(u64 *sta
struct cpu_cf_events {
struct cpumf_ctr_info info;
atomic_t ctr_set[CPUMF_CTR_SET_MAX];
+ atomic64_t alert;
u64 state, tx_state;
unsigned int flags;
unsigned int txn_flags;
@@ -59,6 +60,7 @@ struct cpu_cf_events {
DECLARE_PER_CPU(struct cpu_cf_events, cpu_cf_events);
int __kernel_cpumcf_begin(void);
+unsigned long kernel_cpumcf_alert(int clear);
void __kernel_cpumcf_end(void);
#endif /* _ASM_S390_CPU_MCF_H */
--- a/arch/s390/kernel/perf_cpum_cf.c
+++ b/arch/s390/kernel/perf_cpum_cf.c
@@ -30,6 +30,7 @@ DEFINE_PER_CPU(struct cpu_cf_events, cpu
[CPUMF_CTR_SET_EXT] = ATOMIC_INIT(0),
[CPUMF_CTR_SET_MT_DIAG] = ATOMIC_INIT(0),
},
+ .alert = ATOMIC64_INIT(0),
.state = 0,
.flags = 0,
.txn_flags = 0,
@@ -208,6 +209,9 @@ static void cpumf_measurement_alert(stru
if (alert & CPU_MF_INT_CF_MTDA)
pr_warn("CPU[%i] MT counter data was lost\n",
smp_processor_id());
+
+ /* store alert for special handling by in-kernel users */
+ atomic64_or(alert, &cpuhw->alert);
}
#define PMC_INIT 0
@@ -258,6 +262,20 @@ int __kernel_cpumcf_begin(void)
}
EXPORT_SYMBOL(__kernel_cpumcf_begin);
+/* Obtain the CPU-measurement alerts for the counter facility */
+unsigned long kernel_cpumcf_alert(int clear)
+{
+ struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
+ unsigned long alert;
+
+ alert = atomic64_read(&cpuhw->alert);
+ if (clear)
+ atomic64_set(&cpuhw->alert, 0);
+
+ return alert;
+}
+EXPORT_SYMBOL(kernel_cpumcf_alert);
+
/* Release the CPU-measurement counter facility */
void __kernel_cpumcf_end(void)
{