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s390/cpum_cf: introduce kernel_cpumcf_alert() to obtain measurement alerts 

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>
This commit is contained in:
Hendrik Brueckner 2018-08-08 10:30:37 +02:00 committed by Martin Schwidefsky
parent f944bcdf5b
commit 26b8317f51
2 changed files with 20 additions and 0 deletions
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2
arch/s390/include/asm/cpu_mcf.h
View File

@ -52,6 +52,7 @@ static inline void ctr_set_stop(u64 *state, int ctr_set)
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 */

18
arch/s390/kernel/perf_cpum_cf.c
View File

@ -27,6 +27,7 @@ DEFINE_PER_CPU(struct cpu_cf_events, cpu_cf_events) = {
[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,
@ -205,6 +206,9 @@ static void cpumf_measurement_alert(struct ext_code ext_code,
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
@ -255,6 +259,20 @@ 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)
{