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powerpc/hv_gpci: Add sysfs file inside hv_gpci device to show process…
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…or 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: Athira Rajeev <[email protected]>
Signed-off-by: Kajol Jain <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://msgid.link/[email protected]
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@kjain101 @mpe
kjain101 authored and mpe committed Aug 16, 2023
1 parent 9caf9e2 commit 1a160c2
Showing 1 changed file with 152 additions and 14 deletions.
166 changes: 152 additions & 14 deletions arch/powerpc/perf/hv-gpci.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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));

Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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,
};

Expand Down Expand Up @@ -463,39 +547,93 @@ 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);

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;
attr->show = processor_bus_topology_show;
interface_attrs[INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR] = &attr->attr;

switch (sysinfo_interface_group_index) {
case INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR:
attr->attr.name = "processor_bus_topology";
attr->show = processor_bus_topology_show;
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)
Expand Down

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