Commit 1a160c2a authored by Kajol Jain's avatar Kajol Jain Committed by Michael Ellerman
Browse files

powerpc/hv_gpci: Add sysfs file inside hv_gpci device to show processor config information 



The hcall H_GET_PERF_COUNTER_INFO with counter request value as
PROCESSOR_CONFIG(0X90), can be used to get the system
processor configuration information. To expose the system
processor config information, patch adds sysfs file called
"processor_config" to the "/sys/devices/hv_gpci/interface/"
of hv_gpci pmu driver.

Add enum and sysinfo_counter_request array to get required
counter request value in hv-gpci.c file.
Also add a new function called "sysinfo_device_attr_create",
which will create and return required device attribute to the
add_sysinfo_interface_files function.

The processor_config sysfs file is only available for power10
and above platforms. Add a new macro called
INTERFACE_PROCESSOR_CONFIG_ATTR, which points to the index of
NULL placefolder, for processor_config attribute in the interface_attrs
array. Also add macro INTERFACE_NULL_ATTR which points to index of NULL
attribute in interface_attrs array.

Reviewed-by: default avatarAthira Rajeev <atrajeev@linux.vnet.ibm.com>
Signed-off-by: default avatarKajol Jain <kjain@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230729073455.7918-4-kjain@linux.ibm.com
parent 9caf9e2b

arch/powerpc/perf/hv-gpci.c

+152 −14
Original line number Diff line number Diff line
@@ -102,11 +102,21 @@ static ssize_t cpumask_show(struct device *dev, 
	return cpumap_print_to_pagebuf(true, buf, &hv_gpci_cpumask);

}



/* Counter request value to retrieve system information */

#define PROCESSOR_BUS_TOPOLOGY 0XD0



/* Interface attribute array index to store system information */

#define INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR	6

#define INTERFACE_PROCESSOR_CONFIG_ATTR		7

#define INTERFACE_NULL_ATTR			8



/* Counter request value to retrieve system information */

enum {

	PROCESSOR_BUS_TOPOLOGY,

	PROCESSOR_CONFIG

};



static int sysinfo_counter_request[] = {

	[PROCESSOR_BUS_TOPOLOGY] = 0xD0,

	[PROCESSOR_CONFIG] = 0x90,

};



static DEFINE_PER_CPU(char, hv_gpci_reqb[HGPCI_REQ_BUFFER_SIZE]) __aligned(sizeof(uint64_t));
@@ -187,7 +197,8 @@ static ssize_t processor_bus_topology_show(struct device *dev, struct device_att 
	 * starting_index value implies the starting hardware

	 * chip id.

	 */

	ret = systeminfo_gpci_request(PROCESSOR_BUS_TOPOLOGY, 0, 0, buf, &n, arg);

	ret = systeminfo_gpci_request(sysinfo_counter_request[PROCESSOR_BUS_TOPOLOGY],

			0, 0, buf, &n, arg);



	if (!ret)

		return n;
@@ -220,8 +231,76 @@ static ssize_t processor_bus_topology_show(struct device *dev, struct device_att 


		memset(arg, 0, HGPCI_REQ_BUFFER_SIZE);



		ret = systeminfo_gpci_request(PROCESSOR_BUS_TOPOLOGY, starting_index,

				0, buf, &n, arg);

		ret = systeminfo_gpci_request(sysinfo_counter_request[PROCESSOR_BUS_TOPOLOGY],

				starting_index, 0, buf, &n, arg);



		if (!ret)

			return n;



		if (ret != H_PARAMETER)

			goto out;

	}



	return n;



out:

	put_cpu_var(hv_gpci_reqb);

	return ret;

}



static ssize_t processor_config_show(struct device *dev, struct device_attribute *attr,

					char *buf)

{

	struct hv_gpci_request_buffer *arg;

	unsigned long ret;

	size_t n = 0;



	arg = (void *)get_cpu_var(hv_gpci_reqb);

	memset(arg, 0, HGPCI_REQ_BUFFER_SIZE);



	/*

	 * Pass the counter request value 0x90 corresponds to request

	 * type 'Processor_config', to retrieve

	 * the system processor information.

	 * starting_index value implies the starting hardware

	 * processor index.

	 */

	ret = systeminfo_gpci_request(sysinfo_counter_request[PROCESSOR_CONFIG],

			0, 0, buf, &n, arg);



	if (!ret)

		return n;



	if (ret != H_PARAMETER)

		goto out;



	/*

	 * ret value as 'H_PARAMETER' corresponds to 'GEN_BUF_TOO_SMALL', which

	 * implies that buffer can't accommodate all information, and a partial buffer

	 * returned. To handle that, we need to take subsequent requests

	 * with next starting index to retrieve additional (missing) data.

	 * Below loop do subsequent hcalls with next starting index and add it

	 * to buffer util we get all the information.

	 */

	while (ret == H_PARAMETER) {

		int returned_values = be16_to_cpu(arg->params.returned_values);

		int elementsize = be16_to_cpu(arg->params.cv_element_size);

		int last_element = (returned_values - 1) * elementsize;



		/*

		 * Since the starting index is part of counter_value

		 * buffer elements, use the starting index value in the last

		 * element and add 1 to subsequent hcalls.

		 */

		u32 starting_index = arg->bytes[last_element + 3] +

				(arg->bytes[last_element + 2] << 8) +

				(arg->bytes[last_element + 1] << 16) +

				(arg->bytes[last_element] << 24) + 1;



		memset(arg, 0, HGPCI_REQ_BUFFER_SIZE);



		ret = systeminfo_gpci_request(sysinfo_counter_request[PROCESSOR_CONFIG],

				starting_index, 0, buf, &n, arg);



		if (!ret)

			return n;
@@ -258,6 +337,11 @@ static struct attribute *interface_attrs[] = { 
	 * attribute, set in init function if applicable.

	 */

	NULL,

	/*

	 * This NULL is a placeholder for the processor_config

	 * attribute, set in init function if applicable.

	 */

	NULL,

	NULL,

};
@@ -463,17 +547,24 @@ static int hv_gpci_cpu_hotplug_init(void) 
			  ppc_hv_gpci_cpu_offline);

}



static void add_sysinfo_interface_files(void)

static struct device_attribute *sysinfo_device_attr_create(int

		sysinfo_interface_group_index, u32 req)

{

	struct device_attribute *attr = NULL;

	unsigned long ret;

	struct hv_gpci_request_buffer *arg;



	/* Check for counter request type PROCESSOR_BUS_TOPOLOGY support */

	if (sysinfo_interface_group_index < INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR ||

			sysinfo_interface_group_index >= INTERFACE_NULL_ATTR) {

		pr_info("Wrong interface group index for system information\n");

		return NULL;

	}



	/* Check for given counter request value support */

	arg = (void *)get_cpu_var(hv_gpci_reqb);

	memset(arg, 0, HGPCI_REQ_BUFFER_SIZE);



	arg->params.counter_request = cpu_to_be32(PROCESSOR_BUS_TOPOLOGY);

	arg->params.counter_request = cpu_to_be32(req);



	ret = plpar_hcall_norets(H_GET_PERF_COUNTER_INFO,

			virt_to_phys(arg), HGPCI_REQ_BUFFER_SIZE);
@@ -481,21 +572,68 @@ static void add_sysinfo_interface_files(void) 
	put_cpu_var(hv_gpci_reqb);



	/*

	 * Add processor_bus_topology attribute in the interface_attrs

	 * Add given counter request value attribute in the interface_attrs

	 * attribute array, only for valid return types.

	 */

	if (!ret || ret == H_AUTHORITY || ret == H_PARAMETER) {

		attr = kzalloc(sizeof(*attr), GFP_KERNEL);

		if (!attr)

			return;

			return NULL;



		sysfs_attr_init(&attr->attr);

		attr->attr.name = "processor_bus_topology";

		attr->attr.mode = 0444;



		switch (sysinfo_interface_group_index) {

		case INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR:

			attr->attr.name = "processor_bus_topology";

			attr->show = processor_bus_topology_show;

		interface_attrs[INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR] = &attr->attr;

		break;

		case INTERFACE_PROCESSOR_CONFIG_ATTR:

			attr->attr.name = "processor_config";

			attr->show = processor_config_show;

		break;

		}

	} else

		pr_devel("hcall failed, with error: 0x%lx\n", ret);



	return attr;

}



static void add_sysinfo_interface_files(void)

{

	int sysfs_count;

	struct device_attribute *attr[INTERFACE_NULL_ATTR - INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR];

	int i;



	sysfs_count = INTERFACE_NULL_ATTR - INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR;



	/* Get device attribute for a given counter request value */

	for (i = 0; i < sysfs_count; i++) {

		attr[i] = sysinfo_device_attr_create(i + INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR,

				sysinfo_counter_request[i]);



		if (!attr[i])

			goto out;

	}



	/* Add sysinfo interface attributes in the interface_attrs attribute array */

	for (i = 0; i < sysfs_count; i++)

		interface_attrs[i + INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR] = &attr[i]->attr;



	return;



out:

	/*

	 * The sysinfo interface attributes will be added, only if hcall passed for

	 * all the counter request values. Free the device attribute array incase

	 * of any hcall failure.

	 */

	if (i > 0) {

		while (i >= 0) {

			kfree(attr[i]);

			i--;

		}

	}

}



static int hv_gpci_init(void)