powerpc/hv-24x7: Add rtas call in hv-24x7 driver to get processor details

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_24x7_sys_info() to get system parameter values
like number of sockets, cores per chip and chips per socket. Rtas_call
with token "PROCESSOR_MODULE_INFO" is used to get these values.

Subsequent patch exports these values via sysfs.

Patch also make these parameters default to 1.
Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200525104308.9814-3-kjain@linux.ibm.com

arch/powerpc/include/asm/rtas.h

@@ -483,5 +483,11 @@ static inline void rtas_initialize(void) { };
 
 extern int call_rtas(const char *, int, int, unsigned long *, ...);
 
+#ifdef CONFIG_HV_PERF_CTRS
+void read_24x7_sys_info(void);
+#else
+static inline void read_24x7_sys_info(void) { }
+#endif
+
 #endif /* __KERNEL__ */
 #endif /* _POWERPC_RTAS_H */

arch/powerpc/perf/hv-24x7.c

@@ -20,6 +20,7 @@
 #include <asm/io.h>
 #include <linux/byteorder/generic.h>
 
+#include <asm/rtas.h>
 #include "hv-24x7.h"
 #include "hv-24x7-catalog.h"
 #include "hv-common.h"
@@ -57,6 +58,65 @@ static bool is_physical_domain(unsigned domain)
 	}
 }
 
+/*
+ * The Processor Module Information system parameter allows transferring
+ * of certain processor module information from the platform to the OS.
+ * Refer PAPR+ document to get parameter token value as '43'.
+ */
+
+#define PROCESSOR_MODULE_INFO   43
+
+static u32 phys_sockets;	/* Physical sockets */
+static u32 phys_chipspersocket;	/* Physical chips per socket*/
+static u32 phys_coresperchip; /* Physical cores per chip */
+
+/*
+ * read_24x7_sys_info()
+ * Retrieve the number of sockets and chips per socket and cores per
+ * chip details through the get-system-parameter rtas call.
+ */
+void read_24x7_sys_info(void)
+{
+	int call_status, len, ntypes;
+
+	spin_lock(&rtas_data_buf_lock);
+
+	/*
+	 * Making system parameter: chips and sockets and cores per chip
+	 * default to 1.
+	 */
+	phys_sockets = 1;
+	phys_chipspersocket = 1;
+	phys_coresperchip = 1;
+
+	call_status = rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1,
+				NULL,
+				PROCESSOR_MODULE_INFO,
+				__pa(rtas_data_buf),
+				RTAS_DATA_BUF_SIZE);
+
+	if (call_status != 0) {
+		pr_err("Error calling get-system-parameter %d\n",
+		       call_status);
+	} else {
+		len = be16_to_cpup((__be16 *)&rtas_data_buf[0]);
+		if (len < 8)
+			goto out;
+
+		ntypes = be16_to_cpup((__be16 *)&rtas_data_buf[2]);
+
+		if (!ntypes)
+			goto out;
+
+		phys_sockets = be16_to_cpup((__be16 *)&rtas_data_buf[4]);
+		phys_chipspersocket = be16_to_cpup((__be16 *)&rtas_data_buf[6]);
+		phys_coresperchip = be16_to_cpup((__be16 *)&rtas_data_buf[8]);
+	}
+
+out:
+	spin_unlock(&rtas_data_buf_lock);
+}
+
 /* Domains for which more than one result element are returned for each event. */
 static bool domain_needs_aggregation(unsigned int domain)
 {
@@ -1605,6 +1665,8 @@ static int hv_24x7_init(void)
 	if (r)
 		return r;
 
+	read_24x7_sys_info();
+
 	return 0;
 }