perf_counter: powerpc: Change how processor-specific back-ends get selected

At present, the powerpc generic (processor-independent) perf_counter
code has list of processor back-end modules, and at initialization,
it looks at the PVR (processor version register) and has a switch
statement to select a suitable processor-specific back-end.

This is going to become inconvenient as we add more processor-specific
back-ends, so this inverts the order: now each back-end checks whether
it applies to the current processor, and registers itself if so.
Furthermore, instead of looking at the PVR, back-ends now check the
cur_cpu_spec->oprofile_cpu_type string and match on that.

Lastly, each back-end now specifies a name for itself so the core can
print a nice message when a back-end registers itself.

This doesn't provide any support for unregistering back-ends, but that
wouldn't be hard to do and would allow back-ends to be modules.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: linuxppc-dev@ozlabs.org
Cc: benh@kernel.crashing.org
LKML-Reference: <19000.55529.762227.518531@cargo.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 15 insertions, 1 deletions

diff --git a/arch/powerpc/kernel/power5+-pmu.c b/arch/powerpc/kernel/power5+-pmu.c
index aef144d503b0..f4adca8e98a4 100644
--- a/arch/powerpc/kernel/power5+-pmu.c
+++ b/arch/powerpc/kernel/power5+-pmu.c
@@ -10,7 +10,9 @@
  */
 #include <linux/kernel.h>
 #include <linux/perf_counter.h>
+#include <linux/string.h>
 #include <asm/reg.h>
+#include <asm/cputable.h>
 
 /*
  * Bits in event code for POWER5+ (POWER5 GS) and POWER5++ (POWER5 GS DD3)
@@ -657,7 +659,8 @@ static int power5p_cache_events[C(MAX)][C(OP_MAX)][C(RESULT_MAX)] = {
 	},
 };
 
-struct power_pmu power5p_pmu = {
+static struct power_pmu power5p_pmu = {
+	.name			= "POWER5+/++",
 	.n_counter		= 6,
 	.max_alternatives	= MAX_ALT,
 	.add_fields		= 0x7000000000055ul,
@@ -672,3 +675,14 @@ struct power_pmu power5p_pmu = {
 	.generic_events		= power5p_generic_events,
 	.cache_events		= &power5p_cache_events,
 };
+
+static int init_power5p_pmu(void)
+{
+	if (strcmp(cur_cpu_spec->oprofile_cpu_type, "ppc64/power5+")
+	    && strcmp(cur_cpu_spec->oprofile_cpu_type, "ppc64/power5++"))
+		return -ENODEV;
+
+	return register_power_pmu(&power5p_pmu);
+}
+
+arch_initcall(init_power5p_pmu);