sparc: Don't do expensive hypervisor PCR write unless necessary.

[ Upstream commit 314ff52727fe94dfbe07f3a9a489ab3ca8d8df5a ]

The hypervisor call is only necessary if hypervisor events are
being requested.

So if we're not tracking hypervisor events, simply do a direct
register write.

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/arch/sparc/kernel/pcr.c b/arch/sparc/kernel/pcr.c
index 8ac23e6600804a7975ed59e238dfe707087e807c..878c6824c732bde2799bc9bae0e9d8858135a065 100644 (file)
--- a/arch/sparc/kernel/pcr.c
+++ b/arch/sparc/kernel/pcr.c
@@ -80,8 +80,11 @@ static void n2_pcr_write(u64 val)
 {
        unsigned long ret;
 
-       ret = sun4v_niagara2_setperf(HV_N2_PERF_SPARC_CTL, val);
-       if (ret != HV_EOK)
+       if (val & PCR_N2_HTRACE) {
+               ret = sun4v_niagara2_setperf(HV_N2_PERF_SPARC_CTL, val);
+               if (ret != HV_EOK)
+                       write_pcr(val);
+       } else
                write_pcr(val);
 }