[PATCH 1/1] powerpc/pseries: Interface to represent PAPR firmware attributes
Pratik R. Sampat
psampat at linux.ibm.com
Wed Jun 16 23:42:40 AEST 2021
Adds a generic interface to represent the energy and frequency related
PAPR attributes on the system using the new H_CALL
"H_GET_ENERGY_SCALE_INFO".
H_GET_EM_PARMS H_CALL was previously responsible for exporting this
information in the lparcfg, however the H_GET_EM_PARMS H_CALL
will be deprecated P10 onwards.
The H_GET_ENERGY_SCALE_INFO H_CALL is of the following call format:
hcall(
uint64 H_GET_ENERGY_SCALE_INFO, // Get energy scale info
uint64 flags, // Per the flag request
uint64 firstAttributeId,// The attribute id
uint64 bufferAddress, // Guest physical address of the output buffer
uint64 bufferSize // The size in bytes of the output buffer
);
This H_CALL can query either all the attributes at once with
firstAttributeId = 0, flags = 0 as well as query only one attribute
at a time with firstAttributeId = id
The output buffer consists of the following
1. number of attributes - 8 bytes
2. array offset to the data location - 8 bytes
3. version info - 1 byte
4. A data array of size num attributes, which contains the following:
a. attribute ID - 8 bytes
b. attribute value in number - 8 bytes
c. attribute name in string - 64 bytes
d. attribute value in string - 64 bytes
The new H_CALL exports information in direct string value format, hence
a new interface has been introduced in
/sys/firmware/papr/energy_scale_info to export this information to
userspace in an extensible pass-through format.
The H_CALL returns the name, numeric value and string value (if exists)
The format of exposing the sysfs information is as follows:
/sys/firmware/papr/energy_scale_info/
|-- <id>/
|-- desc
|-- value
|-- value_desc (if exists)
|-- <id>/
|-- desc
|-- value
|-- value_desc (if exists)
...
The energy information that is exported is useful for userspace tools
such as powerpc-utils. Currently these tools infer the
"power_mode_data" value in the lparcfg, which in turn is obtained from
the to be deprecated H_GET_EM_PARMS H_CALL.
On future platforms, such userspace utilities will have to look at the
data returned from the new H_CALL being populated in this new sysfs
interface and report this information directly without the need of
interpretation.
Signed-off-by: Pratik R. Sampat <psampat at linux.ibm.com>
---
.../sysfs-firmware-papr-energy-scale-info | 26 ++
arch/powerpc/include/asm/hvcall.h | 21 +-
arch/powerpc/kvm/trace_hv.h | 1 +
arch/powerpc/platforms/pseries/Makefile | 3 +-
.../pseries/papr_platform_attributes.c | 292 ++++++++++++++++++
5 files changed, 341 insertions(+), 2 deletions(-)
create mode 100644 Documentation/ABI/testing/sysfs-firmware-papr-energy-scale-info
create mode 100644 arch/powerpc/platforms/pseries/papr_platform_attributes.c
diff --git a/Documentation/ABI/testing/sysfs-firmware-papr-energy-scale-info b/Documentation/ABI/testing/sysfs-firmware-papr-energy-scale-info
new file mode 100644
index 000000000000..499bc1ae173a
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-firmware-papr-energy-scale-info
@@ -0,0 +1,26 @@
+What: /sys/firmware/papr/energy_scale_info
+Date: June 2021
+Contact: Linux for PowerPC mailing list <linuxppc-dev at ozlabs.org>
+Description: Director hosting a set of platform attributes on Linux
+ running as a PAPR guest.
+
+ Each file in a directory contains a platform
+ attribute hierarchy pertaining to performance/
+ energy-savings mode and processor frequency.
+
+What: /sys/firmware/papr/energy_scale_info/<id>
+ /sys/firmware/papr/energy_scale_info/<id>/desc
+ /sys/firmware/papr/energy_scale_info/<id>/value
+ /sys/firmware/papr/energy_scale_info/<id>/value_desc
+Date: June 2021
+Contact: Linux for PowerPC mailing list <linuxppc-dev at ozlabs.org>
+Description: PAPR attributes directory for POWERVM servers
+
+ This directory provides PAPR information. It
+ contains below sysfs attributes:
+
+ - desc: File contains the name of attribute <id>
+
+ - value: Numeric value of attribute <id>
+
+ - value_desc: String value of attribute <id>
diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h
index e3b29eda8074..19a2a8c77a49 100644
--- a/arch/powerpc/include/asm/hvcall.h
+++ b/arch/powerpc/include/asm/hvcall.h
@@ -316,7 +316,8 @@
#define H_SCM_PERFORMANCE_STATS 0x418
#define H_RPT_INVALIDATE 0x448
#define H_SCM_FLUSH 0x44C
-#define MAX_HCALL_OPCODE H_SCM_FLUSH
+#define H_GET_ENERGY_SCALE_INFO 0x450
+#define MAX_HCALL_OPCODE H_GET_ENERGY_SCALE_INFO
/* Scope args for H_SCM_UNBIND_ALL */
#define H_UNBIND_SCOPE_ALL (0x1)
@@ -631,6 +632,24 @@ struct hv_gpci_request_buffer {
uint8_t bytes[HGPCI_MAX_DATA_BYTES];
} __packed;
+#define MAX_EM_ATTRS 10
+#define MAX_EM_DATA_BYTES \
+ (sizeof(struct energy_scale_attributes) * MAX_EM_ATTRS)
+struct energy_scale_attributes {
+ __be64 attr_id;
+ __be64 attr_value;
+ unsigned char attr_desc[64];
+ unsigned char attr_value_desc[64];
+} __packed;
+
+struct hv_energy_scale_buffer {
+ __be64 num_attr;
+ __be64 array_offset;
+ __u8 data_header_version;
+ unsigned char data[MAX_EM_DATA_BYTES];
+} __packed;
+
+
#endif /* __ASSEMBLY__ */
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_HVCALL_H */
diff --git a/arch/powerpc/kvm/trace_hv.h b/arch/powerpc/kvm/trace_hv.h
index 830a126e095d..38cd0ed0a617 100644
--- a/arch/powerpc/kvm/trace_hv.h
+++ b/arch/powerpc/kvm/trace_hv.h
@@ -115,6 +115,7 @@
{H_VASI_STATE, "H_VASI_STATE"}, \
{H_ENABLE_CRQ, "H_ENABLE_CRQ"}, \
{H_GET_EM_PARMS, "H_GET_EM_PARMS"}, \
+ {H_GET_ENERGY_SCALE_INFO, "H_GET_ENERGY_SCALE_INFO"}, \
{H_SET_MPP, "H_SET_MPP"}, \
{H_GET_MPP, "H_GET_MPP"}, \
{H_HOME_NODE_ASSOCIATIVITY, "H_HOME_NODE_ASSOCIATIVITY"}, \
diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile
index c8a2b0b05ac0..d14fca89ac25 100644
--- a/arch/powerpc/platforms/pseries/Makefile
+++ b/arch/powerpc/platforms/pseries/Makefile
@@ -6,7 +6,8 @@ obj-y := lpar.o hvCall.o nvram.o reconfig.o \
of_helpers.o \
setup.o iommu.o event_sources.o ras.o \
firmware.o power.o dlpar.o mobility.o rng.o \
- pci.o pci_dlpar.o eeh_pseries.o msi.o
+ pci.o pci_dlpar.o eeh_pseries.o msi.o \
+ papr_platform_attributes.o
obj-$(CONFIG_SMP) += smp.o
obj-$(CONFIG_SCANLOG) += scanlog.o
obj-$(CONFIG_KEXEC_CORE) += kexec.o
diff --git a/arch/powerpc/platforms/pseries/papr_platform_attributes.c b/arch/powerpc/platforms/pseries/papr_platform_attributes.c
new file mode 100644
index 000000000000..498c74a5e9ab
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/papr_platform_attributes.c
@@ -0,0 +1,292 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * PAPR platform energy attributes driver
+ *
+ * This driver creates a sys file at /sys/firmware/papr/ which contains
+ * files keyword - value pairs that specify energy configuration of the system.
+ *
+ * Copyright 2021 IBM Corp.
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/hugetlb.h>
+#include <asm/lppaca.h>
+#include <asm/hvcall.h>
+#include <asm/firmware.h>
+#include <asm/time.h>
+#include <asm/prom.h>
+#include <asm/vdso_datapage.h>
+#include <asm/vio.h>
+#include <asm/mmu.h>
+#include <asm/machdep.h>
+#include <asm/drmem.h>
+
+#include "pseries.h"
+
+#define MAX_ATTRS 3
+#define MAX_NAME_LEN 16
+
+struct papr_attr {
+ u64 id;
+ struct kobj_attribute attr;
+};
+struct papr_group {
+ char name[MAX_NAME_LEN];
+ struct attribute_group pg;
+ struct papr_attr *pgattrs;
+} *pgs;
+
+struct kobject *papr_kobj;
+struct kobject *escale_kobj;
+struct hv_energy_scale_buffer *em_buf;
+struct energy_scale_attributes *ea;
+
+static ssize_t papr_show_desc(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ struct papr_attr *pattr = container_of(attr, struct papr_attr, attr);
+ int idx, ret = 0;
+
+ /*
+ * We do not expect the name to change, hence use the old value
+ * and save a HCALL
+ */
+ for (idx = 0; idx < be64_to_cpu(em_buf->num_attr); idx++) {
+ if (pattr->id == be64_to_cpu(ea[idx].attr_id)) {
+ ret = sprintf(buf, "%s\n", ea[idx].attr_desc);
+ if (ret < 0)
+ ret = -EIO;
+ break;
+ }
+ }
+
+ return ret;
+}
+
+static ssize_t papr_show_value(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ struct papr_attr *pattr = container_of(attr, struct papr_attr, attr);
+ struct hv_energy_scale_buffer *t_buf;
+ struct energy_scale_attributes *t_ea;
+ int data_offset, ret = 0;
+
+ t_buf = kmalloc(sizeof(*t_buf), GFP_KERNEL);
+ if (t_buf == NULL)
+ return -ENOMEM;
+
+ ret = plpar_hcall_norets(H_GET_ENERGY_SCALE_INFO, 0,
+ pattr->id, virt_to_phys(t_buf),
+ sizeof(*t_buf));
+
+ if (ret != H_SUCCESS) {
+ pr_warn("hcall failed: H_GET_ENERGY_SCALE_INFO");
+ goto out;
+ }
+
+ data_offset = be64_to_cpu(t_buf->array_offset) -
+ (sizeof(t_buf->num_attr) +
+ sizeof(t_buf->array_offset) +
+ sizeof(t_buf->data_header_version));
+
+ t_ea = (struct energy_scale_attributes *) &t_buf->data[data_offset];
+
+ ret = sprintf(buf, "%llu\n", be64_to_cpu(t_ea->attr_value));
+ if (ret < 0)
+ ret = -EIO;
+out:
+ kfree(t_buf);
+
+ return ret;
+}
+
+static ssize_t papr_show_value_desc(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ struct papr_attr *pattr = container_of(attr, struct papr_attr, attr);
+ struct hv_energy_scale_buffer *t_buf;
+ struct energy_scale_attributes *t_ea;
+ int data_offset, ret = 0;
+
+ t_buf = kmalloc(sizeof(*t_buf), GFP_KERNEL);
+ if (t_buf == NULL)
+ return -ENOMEM;
+
+ ret = plpar_hcall_norets(H_GET_ENERGY_SCALE_INFO, 0,
+ pattr->id, virt_to_phys(t_buf),
+ sizeof(*t_buf));
+
+ if (ret != H_SUCCESS) {
+ pr_warn("hcall failed: H_GET_ENERGY_SCALE_INFO");
+ goto out;
+ }
+
+ data_offset = be64_to_cpu(t_buf->array_offset) -
+ (sizeof(t_buf->num_attr) +
+ sizeof(t_buf->array_offset) +
+ sizeof(t_buf->data_header_version));
+
+ t_ea = (struct energy_scale_attributes *) &t_buf->data[data_offset];
+
+ ret = sprintf(buf, "%s\n", t_ea->attr_value_desc);
+ if (ret < 0)
+ ret = -EIO;
+out:
+ kfree(t_buf);
+
+ return ret;
+}
+
+static struct papr_ops_info {
+ const char *attr_name;
+ ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,
+ char *buf);
+} ops_info[] = {
+ { "desc", papr_show_desc },
+ { "value", papr_show_value },
+ { "value_desc", papr_show_value_desc },
+};
+
+static void add_attr(u64 id, int index, struct papr_attr *attr)
+{
+ attr->id = id;
+ sysfs_attr_init(&attr->attr.attr);
+ attr->attr.attr.name = ops_info[index].attr_name;
+ attr->attr.attr.mode = 0444;
+ attr->attr.show = ops_info[index].show;
+}
+
+static int add_attr_group(u64 id, int len, struct papr_group *pg,
+ bool show_val_desc)
+{
+ int i;
+
+ for (i = 0; i < len; i++) {
+ if (!strcmp(ops_info[i].attr_name, "value_desc") &&
+ !show_val_desc) {
+ continue;
+ }
+ add_attr(id, i, &pg->pgattrs[i]);
+ pg->pg.attrs[i] = &pg->pgattrs[i].attr.attr;
+ }
+
+ return sysfs_create_group(escale_kobj, &pg->pg);
+}
+
+
+static int __init papr_init(void)
+{
+ uint64_t num_attr;
+ int ret, idx, i, data_offset;
+
+ em_buf = kmalloc(sizeof(*em_buf), GFP_KERNEL);
+ if (em_buf == NULL)
+ return -ENOMEM;
+ /*
+ * hcall(
+ * uint64 H_GET_ENERGY_SCALE_INFO, // Get energy scale info
+ * uint64 flags, // Per the flag request
+ * uint64 firstAttributeId, // The attribute id
+ * uint64 bufferAddress, // Guest physical address of the output buffer
+ * uint64 bufferSize); // The size in bytes of the output buffer
+ */
+ ret = plpar_hcall_norets(H_GET_ENERGY_SCALE_INFO, 0, 0,
+ virt_to_phys(em_buf), sizeof(*em_buf));
+
+ if (!firmware_has_feature(FW_FEATURE_LPAR) || ret != H_SUCCESS ||
+ em_buf->data_header_version != 0x1) {
+ pr_warn("hcall failed: H_GET_ENERGY_SCALE_INFO");
+ goto out;
+ }
+
+ num_attr = be64_to_cpu(em_buf->num_attr);
+
+ /*
+ * Typecast the energy buffer to the attribute structure at the offset
+ * specified in the buffer
+ */
+ data_offset = be64_to_cpu(em_buf->array_offset) -
+ (sizeof(em_buf->num_attr) +
+ sizeof(em_buf->array_offset) +
+ sizeof(em_buf->data_header_version));
+
+ ea = (struct energy_scale_attributes *) &em_buf->data[data_offset];
+
+ pgs = kcalloc(num_attr, sizeof(*pgs), GFP_KERNEL);
+ if (!pgs)
+ goto out_pgs;
+
+ papr_kobj = kobject_create_and_add("papr", firmware_kobj);
+ if (!papr_kobj) {
+ pr_warn("kobject_create_and_add papr failed\n");
+ goto out_kobj;
+ }
+
+ escale_kobj = kobject_create_and_add("energy_scale_info", papr_kobj);
+ if (!escale_kobj) {
+ pr_warn("kobject_create_and_add energy_scale_info failed\n");
+ goto out_ekobj;
+ }
+
+ for (idx = 0; idx < num_attr; idx++) {
+ char buf[4];
+ bool show_val_desc = true;
+
+ pgs[idx].pgattrs = kcalloc(MAX_ATTRS,
+ sizeof(*pgs[idx].pgattrs),
+ GFP_KERNEL);
+ if (!pgs[idx].pgattrs)
+ goto out_kobj;
+
+ pgs[idx].pg.attrs = kcalloc(MAX_ATTRS + 1,
+ sizeof(*pgs[idx].pg.attrs),
+ GFP_KERNEL);
+ if (!pgs[idx].pg.attrs) {
+ kfree(pgs[idx].pgattrs);
+ goto out_kobj;
+ }
+
+ sprintf(buf, "%lld", be64_to_cpu(ea[idx].attr_id));
+ pgs[idx].pg.name = buf;
+
+ /* Do not add the value description if it does not exist */
+ if (strlen(ea[idx].attr_value_desc) == 0)
+ show_val_desc = false;
+
+ if (add_attr_group(be64_to_cpu(ea[idx].attr_id),
+ MAX_ATTRS, &pgs[idx], show_val_desc)) {
+ pr_warn("Failed to create papr attribute group %s\n",
+ pgs[idx].pg.name);
+ goto out_pgattrs;
+ }
+ }
+
+ return 0;
+
+out_pgattrs:
+ for (i = 0; i < MAX_ATTRS; i++) {
+ kfree(pgs[i].pgattrs);
+ kfree(pgs[i].pg.attrs);
+ }
+out_ekobj:
+ kobject_put(escale_kobj);
+out_kobj:
+ kobject_put(papr_kobj);
+out_pgs:
+ kfree(pgs);
+out:
+ kfree(em_buf);
+
+ return -ENOMEM;
+}
+
+machine_device_initcall(pseries, papr_init);
--
2.30.2
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