s390/perf,oprofile: Share sampling facility

Introduce reserve/release functions to share the sampling facility
between perf and oprofile.
Also improve error handling for the sampling facility support in perf.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 12 insertions, 5 deletions

diff --git a/arch/s390/kernel/perf_cpum_sf.c b/arch/s390/kernel/perf_cpum_sf.c
index 52bf36ee91aa..ae5e0192160d 100644
--- a/arch/s390/kernel/perf_cpum_sf.c
+++ b/arch/s390/kernel/perf_cpum_sf.c
@@ -260,16 +260,12 @@ static int sf_disable(void)
 
 #define PMC_INIT      0
 #define PMC_RELEASE   1
+#define PMC_FAILURE   2
 static void setup_pmc_cpu(void *flags)
 {
         int err;
         struct cpu_hw_sf *cpusf = &__get_cpu_var(cpu_hw_sf);
 
-        /* XXX Improve error handling and pass a flag in the *flags
-         *     variable to indicate failures.  Alternatively, ignore
-         *     (print) errors here and let the PMU functions fail if
-         *     the per-cpu PMU_F_RESERVED flag is not.
-         */
         err = 0;
         switch (*((int *) flags)) {
         case PMC_INIT:
@@ -299,6 +295,8 @@ static void setup_pmc_cpu(void *flags)
                                     "setup_pmc_cpu: released: cpuhw=%p\n", cpusf);
                 break;
         }
+        if (err)
+                *((int *) flags) |= PMC_FAILURE;
 }
 
 static void release_pmc_hardware(void)
@@ -307,13 +305,22 @@ static void release_pmc_hardware(void)
 
         irq_subclass_unregister(IRQ_SUBCLASS_MEASUREMENT_ALERT);
         on_each_cpu(setup_pmc_cpu, &flags, 1);
+        perf_release_sampling();
 }
 
 static int reserve_pmc_hardware(void)
 {
         int flags = PMC_INIT;
+        int err;
 
+        err = perf_reserve_sampling();
+        if (err)
+                return err;
         on_each_cpu(setup_pmc_cpu, &flags, 1);
+        if (flags & PMC_FAILURE) {
+                release_pmc_hardware();
+                return -ENODEV;
+        }
         irq_subclass_register(IRQ_SUBCLASS_MEASUREMENT_ALERT);
 
         return 0;