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

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The hcall H_GET_PERF_COUNTER_INFO with counter request value as
PROCESSOR_BUS_TOPOLOGY(0XD0), can be used to get the system
topology information. To expose the system topology information,
patch adds sysfs file called "processor_bus_topology" to the
"/sys/devices/hv_gpci/interface/" of hv_gpci pmu driver.

Add macro for PROCESSOR_BUS_TOPOLOGY counter request value
in hv-gpci.c file. Also add a new function called
"systeminfo_gpci_request", to make the H_GET_PERF_COUNTER_INFO hcall
with added macro and populates the output buffer.

The processor_bus_topology sysfs file is only available for power10
and above platforms. Add a new function called
"add_sysinfo_interface_files", which will add processor_bus_topology
attribute in the interface_attrs array, only for power10 and
above platforms.
Also add macro INTERFACE_PROCESSOR_BUS_TOPOLOGY_ATTR in hv-gpci.c
file, which points to the index of NULL placefolder, for
processor_bus_topology attribute.

Reviewed-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230729073455.7918-2-kjain@linux.ibm.com
This commit is contained in:
Kajol Jain 2023-07-29 13:04:46 +05:30 committed by Michael Ellerman
parent 58b6fed89a
commit 71f1c39647
1 changed files with 179 additions and 2 deletions
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181
arch/powerpc/perf/hv-gpci.c
View File

@ -102,6 +102,141 @@ 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
static DEFINE_PER_CPU(char, hv_gpci_reqb[HGPCI_REQ_BUFFER_SIZE]) __aligned(sizeof(uint64_t));
static unsigned long systeminfo_gpci_request(u32 req, u32 starting_index,
u16 secondary_index, char *buf,
size_t *n, struct hv_gpci_request_buffer *arg)
{
unsigned long ret;
size_t i, j;
arg->params.counter_request = cpu_to_be32(req);
arg->params.starting_index = cpu_to_be32(starting_index);
arg->params.secondary_index = cpu_to_be16(secondary_index);
ret = plpar_hcall_norets(H_GET_PERF_COUNTER_INFO,
virt_to_phys(arg), HGPCI_REQ_BUFFER_SIZE);
/*
* ret value as 'H_PARAMETER' corresponds to 'GEN_BUF_TOO_SMALL',
* which means that the current buffer size cannot accommodate
* all the information and a partial buffer returned.
* hcall fails incase of ret value other than H_SUCCESS or H_PARAMETER.
*
* ret value as H_AUTHORITY implies that partition is not permitted to retrieve
* performance information, and required to set
* "Enable Performance Information Collection" option.
*/
if (ret == H_AUTHORITY)
return -EPERM;
/*
* hcall can fail with other possible ret value like H_PRIVILEGE/H_HARDWARE
* because of invalid buffer-length/address or due to some hardware
* error.
*/
if (ret && (ret != H_PARAMETER))
return -EIO;
/*
* hcall H_GET_PERF_COUNTER_INFO populates the 'returned_values'
* to show the total number of counter_value array elements
* returned via hcall.
* hcall also populates 'cv_element_size' corresponds to individual
* counter_value array element size. Below loop go through all
* counter_value array elements as per their size and add it to
* the output buffer.
*/
for (i = 0; i < be16_to_cpu(arg->params.returned_values); i++) {
j = i * be16_to_cpu(arg->params.cv_element_size);
for (; j < (i + 1) * be16_to_cpu(arg->params.cv_element_size); j++)
*n += sprintf(buf + *n, "%02x", (u8)arg->bytes[j]);
*n += sprintf(buf + *n, "\n");
}
if (*n >= PAGE_SIZE) {
pr_info("System information exceeds PAGE_SIZE\n");
return -EFBIG;
}
return ret;
}
static ssize_t processor_bus_topology_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 0xD0 corresponds to request
* type 'Processor_bus_topology', to retrieve
* the system topology information.
* starting_index value implies the starting hardware
* chip id.
*/
ret = systeminfo_gpci_request(PROCESSOR_BUS_TOPOLOGY, 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 make 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 value is part of counter_value
* buffer elements, use the starting index value in the last
* element and add 1 to make 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(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 DEVICE_ATTR_RO(kernel_version);
static DEVICE_ATTR_RO(cpumask);
@ -118,6 +253,11 @@ static struct attribute *interface_attrs[] = {
&hv_caps_attr_expanded.attr,
&hv_caps_attr_lab.attr,
&hv_caps_attr_collect_privileged.attr,
/*
* This NULL is a placeholder for the processor_bus_topology
* attribute, set in init function if applicable.
*/
NULL,
NULL,
};
@ -143,8 +283,6 @@ static const struct attribute_group *attr_groups[] = {
NULL,
};
static DEFINE_PER_CPU(char, hv_gpci_reqb[HGPCI_REQ_BUFFER_SIZE]) __aligned(sizeof(uint64_t));
static unsigned long single_gpci_request(u32 req, u32 starting_index,
u16 secondary_index, u8 version_in, u32 offset, u8 length,
u64 *value)
@ -325,6 +463,41 @@ static int hv_gpci_cpu_hotplug_init(void)
ppc_hv_gpci_cpu_offline);
}
static void add_sysinfo_interface_files(void)
{
struct device_attribute *attr = NULL;
unsigned long ret;
struct hv_gpci_request_buffer *arg;
/* Check for counter request type PROCESSOR_BUS_TOPOLOGY 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);
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
* attribute array, only for valid return types.
*/
if (!ret || ret == H_AUTHORITY || ret == H_PARAMETER) {
attr = kzalloc(sizeof(*attr), GFP_KERNEL);
if (!attr)
return;
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;
} else
pr_devel("hcall failed, with error: 0x%lx\n", ret);
}
static int hv_gpci_init(void)
{
int r;
@ -388,6 +561,10 @@ static int hv_gpci_init(void)
if (r)
return r;
/* sysinfo interface files are only available for power10 and above platforms */
if (PVR_VER(mfspr(SPRN_PVR)) >= PVR_POWER10)
add_sysinfo_interface_files();
return 0;
}