[PATCH v7 2/5] powerpc/hv-24x7: Add rtas call in hv-24x7 driver to get processor details

Kajol Jain
2020-03-27T06:37:24Z

For hv_24x7 socket/chip level events, specific chip-id to which
the data requested should be added as part of pmu events.
But number of chips/socket in the system details are not exposed.

Patch implements read_sys_info_pseries() to get system
parameter values like number of sockets and chips per socket.
Rtas_call with token "PROCESSOR_MODULE_INFO"
is used to get these values.

Sub-sequent patch exports these values via sysfs.

Patch also make these parameters default to 1.

Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
---
arch/powerpc/perf/hv-24x7.c | 72 ++++++++++++++++++++++++
arch/powerpc/platforms/pseries/pseries.h | 3 +
2 files changed, 75 insertions(+)

diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c
index 48e8f4b17b91..9ae00f29bd21 100644
--- a/arch/powerpc/perf/hv-24x7.c
+++ b/arch/powerpc/perf/hv-24x7.c
@@ -20,6 +20,11 @@
#include <asm/io.h>
#include <linux/byteorder/generic.h>

+#ifdef CONFIG_PPC_RTAS
+#include <asm/rtas.h>
+#include <../../platforms/pseries/pseries.h>
+#endif
+
#include "hv-24x7.h"
#include "hv-24x7-catalog.h"
#include "hv-common.h"
@@ -57,6 +62,69 @@ static bool is_physical_domain(unsigned domain)
}
}

+#ifdef CONFIG_PPC_RTAS
+#define PROCESSOR_MODULE_INFO 43
+#define PROCESSOR_MAX_LENGTH (8 * 1024)
+
+static int strbe16toh(const char *buf, int offset)
+{
+ return (buf[offset] << 8) + buf[offset + 1];
+}
+
+static u32 physsockets; /* Physical sockets */
+static u32 physchips; /* Physical chips */
+
+/*
+ * Function read_sys_info_pseries() make a rtas_call which require
+ * data buffer of size 8K. As standard 'rtas_data_buf' is of size
+ * 4K, we are adding new local buffer 'rtas_local_data_buf'.
+ */
+char rtas_local_data_buf[PROCESSOR_MAX_LENGTH] __cacheline_aligned;
+
+/*
+ * read_sys_info_pseries()
+ * Retrieve the number of sockets and chips per socket details
+ * through the get-system-parameter rtas call.
+ */
+void read_sys_info_pseries(void)
+{
+ int call_status, len, ntypes;
+
+ /*
+ * Making system parameter: chips and sockets default to 1.
+ */
+ physsockets = 1;
+ physchips = 1;
+ memset(rtas_local_data_buf, 0, PROCESSOR_MAX_LENGTH);
+ spin_lock(&rtas_data_buf_lock);
+
+ call_status = rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1,
+ NULL,
+ PROCESSOR_MODULE_INFO,
+ __pa(rtas_local_data_buf),
+ PROCESSOR_MAX_LENGTH);
+
+ spin_unlock(&rtas_data_buf_lock);
+
+ if (call_status != 0) {
+ pr_info("%s %s Error calling get-system-parameter (0x%x)\n",
+ __FILE__, __func__, call_status);
+ } else {
+ rtas_local_data_buf[PROCESSOR_MAX_LENGTH - 1] = '\0';
+ len = strbe16toh(rtas_local_data_buf, 0);
+ if (len < 6)
+ return;
+
+ ntypes = strbe16toh(rtas_local_data_buf, 2);
+
+ if (!ntypes)
+ return;
+ physsockets = strbe16toh(rtas_local_data_buf, 4);
+ physchips = strbe16toh(rtas_local_data_buf, 6);
+ }
+}
+#endif /* CONFIG_PPC_RTAS */
+
/* Domains for which more than one result element are returned for each event. */
static bool domain_needs_aggregation(unsigned int domain)
{
@@ -1605,6 +1673,10 @@ static int hv_24x7_init(void)
if (r)
return r;

+#ifdef CONFIG_PPC_RTAS
+ read_sys_info_pseries();
+#endif
+
return 0;
}

diff --git a/arch/powerpc/platforms/pseries/pseries.h b/arch/powerpc/platforms/pseries/pseries.h
index 13fa370a87e4..1727559ce304 100644
--- a/arch/powerpc/platforms/pseries/pseries.h
+++ b/arch/powerpc/platforms/pseries/pseries.h
@@ -19,6 +19,9 @@ extern void request_event_sources_irqs(struct device_node *np,
struct pt_regs;

extern int pSeries_system_reset_exception(struct pt_regs *regs);
+#ifdef CONFIG_PPC_RTAS
+extern void read_sys_info_pseries(void);
+#endif
extern int pSeries_machine_check_exception(struct pt_regs *regs);
extern long pseries_machine_check_realmode(struct pt_regs *regs);

--
2.18.1