LinuxLists.cc - [PATCH v9 0/2] Interface to represent PAPR firmware attributes

2022-02-17 13:22:33

Subject: [PATCH v9 0/2] Interface to represent PAPR firmware attributes

RFC: https://lkml.org/lkml/2021/6/4/791
PATCH v1: https://lkml.org/lkml/2021/6/16/805
PATCH v2: https://lkml.org/lkml/2021/7/6/138
PATCH v3: https://lkml.org/lkml/2021/7/12/2799
PATCH v4: https://lkml.org/lkml/2021/7/16/532
PATCH v5: https://lkml.org/lkml/2021/7/19/247
PATCH v6: https://lkml.org/lkml/2021/7/20/36
PATCH v7: https://lkml.org/lkml/2021/7/23/26
PATCH v8: https://lkml.org/lkml/2021/9/28/554

Changelog v8-->v9
1. Edited interface documentation to be in line with the current
formatting
2. Created a parent abstraction for cleaning up the functions exporting
energy scale information. Also commented the need to make a new hcall
each time instead of caching objects as energy modes may change
dynamically
3. Added a dynamically reallocating buffer for the hcall return
attributes in the case of H_PARTIAL and H_P4
4. Added support to discover H_GET_ENERGY_SCALE_INFO feature via the
ibm,hypertas-function device tree property
5. Removed versioning check for hcall as the PAPR documents backward
compatibility support for this hcall
6. Decoupled allocation and registering for sysfs interfaces for
handling faliures gracefully
7. Cleaned up functions, return codes, variable and label naming as per
comments

Additional comment:
Currently the interface is modeled to calling it as
papr_platform_attributes.c as to keep it open to adding more attributes
in the future. However, if believed that its not necessary then I
could rename it to energy_scale_info.c instead and remove the "papr"
parent directory from the interface as well.

Pratik R. Sampat (2):
powerpc/pseries: Interface to represent PAPR firmware attributes
selftest/powerpc: Add PAPR sysfs attributes sniff test

.../sysfs-firmware-papr-energy-scale-info | 29 ++
arch/powerpc/include/asm/firmware.h | 4 +-
arch/powerpc/include/asm/hvcall.h | 3 +-
arch/powerpc/kvm/trace_hv.h | 1 +
arch/powerpc/platforms/pseries/Makefile | 3 +-
arch/powerpc/platforms/pseries/firmware.c | 1 +
.../pseries/papr_platform_attributes.c | 361 ++++++++++++++++++
tools/testing/selftests/powerpc/Makefile | 1 +
.../powerpc/papr_attributes/.gitignore | 2 +
.../powerpc/papr_attributes/Makefile | 7 +
.../powerpc/papr_attributes/attr_test.c | 107 ++++++
11 files changed, 516 insertions(+), 3 deletions(-)
create mode 100644 Documentation/ABI/testing/sysfs-firmware-papr-energy-scale-info
create mode 100644 arch/powerpc/platforms/pseries/papr_platform_attributes.c
create mode 100644 tools/testing/selftests/powerpc/papr_attributes/.gitignore
create mode 100644 tools/testing/selftests/powerpc/papr_attributes/Makefile
create mode 100644 tools/testing/selftests/powerpc/papr_attributes/attr_test.c

--
2.34.1

2022-02-17 16:28:51

by Pratik R. Sampat

[permalink] [raw]

Subject: [PATCH v9 2/2] selftest/powerpc: Add PAPR sysfs attributes sniff test

Include a testcase to check if the sysfs files for energy and frequency
related have its related attribute files exist and populated

Signed-off-by: Pratik R. Sampat <[email protected]>
---
tools/testing/selftests/powerpc/Makefile | 1 +
.../powerpc/papr_attributes/.gitignore | 2 +
.../powerpc/papr_attributes/Makefile | 7 ++
.../powerpc/papr_attributes/attr_test.c | 107 ++++++++++++++++++
4 files changed, 117 insertions(+)
create mode 100644 tools/testing/selftests/powerpc/papr_attributes/.gitignore
create mode 100644 tools/testing/selftests/powerpc/papr_attributes/Makefile
create mode 100644 tools/testing/selftests/powerpc/papr_attributes/attr_test.c

diff --git a/tools/testing/selftests/powerpc/Makefile b/tools/testing/selftests/powerpc/Makefile
index 0830e63818c1..c68c872efb23 100644
--- a/tools/testing/selftests/powerpc/Makefile
+++ b/tools/testing/selftests/powerpc/Makefile
@@ -30,6 +30,7 @@ SUB_DIRS = alignment \
eeh \
vphn \
math \
+ papr_attributes \
ptrace \
security

diff --git a/tools/testing/selftests/powerpc/papr_attributes/.gitignore b/tools/testing/selftests/powerpc/papr_attributes/.gitignore
new file mode 100644
index 000000000000..d5f42b6d9e99
--- /dev/null
+++ b/tools/testing/selftests/powerpc/papr_attributes/.gitignore
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+attr_test
diff --git a/tools/testing/selftests/powerpc/papr_attributes/Makefile b/tools/testing/selftests/powerpc/papr_attributes/Makefile
new file mode 100644
index 000000000000..e899712d49db
--- /dev/null
+++ b/tools/testing/selftests/powerpc/papr_attributes/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0
+TEST_GEN_PROGS := attr_test
+
+top_srcdir = ../../../../..
+include ../../lib.mk
+
+$(TEST_GEN_PROGS): ../harness.c ../utils.c
\ No newline at end of file
diff --git a/tools/testing/selftests/powerpc/papr_attributes/attr_test.c b/tools/testing/selftests/powerpc/papr_attributes/attr_test.c
new file mode 100644
index 000000000000..bab0dc06e90b
--- /dev/null
+++ b/tools/testing/selftests/powerpc/papr_attributes/attr_test.c
@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * PAPR Energy attributes sniff test
+ * This checks if the papr folders and contents are populated relating to
+ * the energy and frequency attributes
+ *
+ * Copyright 2022, Pratik Rajesh Sampat, IBM Corp.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <dirent.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#include "utils.h"
+
+enum energy_freq_attrs {
+ POWER_PERFORMANCE_MODE = 1,
+ IDLE_POWER_SAVER_STATUS = 2,
+ MIN_FREQ = 3,
+ STAT_FREQ = 4,
+ MAX_FREQ = 6,
+ PROC_FOLDING_STATUS = 8
+};
+
+enum type {
+ INVALID,
+ STR_VAL,
+ NUM_VAL
+};
+
+int value_type(int id)
+{
+ int val_type;
+
+ switch (id) {
+ case POWER_PERFORMANCE_MODE:
+ case IDLE_POWER_SAVER_STATUS:
+ val_type = STR_VAL;
+ break;
+ case MIN_FREQ:
+ case STAT_FREQ:
+ case MAX_FREQ:
+ case PROC_FOLDING_STATUS:
+ val_type = NUM_VAL;
+ break;
+ default:
+ val_type = INVALID;
+ }
+
+ return val_type;
+}
+
+int verify_energy_info(void)
+{
+ const char *path = "/sys/firmware/papr/energy_scale_info";
+ struct dirent *entry;
+ struct stat s;
+ DIR *dirp;
+
+ if (stat(path, &s) || !S_ISDIR(s.st_mode))
+ return -1;
+ dirp = opendir(path);
+
+ while ((entry = readdir(dirp)) != NULL) {
+ char file_name[64];
+ int id, attr_type;
+ FILE *f;
+
+ if (strcmp(entry->d_name, ".") == 0 ||
+ strcmp(entry->d_name, "..") == 0)
+ continue;
+
+ id = atoi(entry->d_name);
+ attr_type = value_type(id);
+ if (attr_type == INVALID)
+ return -1;
+
+ /* Check if the files exist and have data in them */
+ sprintf(file_name, "%s/%d/desc", path, id);
+ f = fopen(file_name, "r");
+ if (!f || fgetc(f) == EOF)
+ return -1;
+
+ sprintf(file_name, "%s/%d/value", path, id);
+ f = fopen(file_name, "r");
+ if (!f || fgetc(f) == EOF)
+ return -1;
+
+ if (attr_type == STR_VAL) {
+ sprintf(file_name, "%s/%d/value_desc", path, id);
+ f = fopen(file_name, "r");
+ if (!f || fgetc(f) == EOF)
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+int main(void)
+{
+ return test_harness(verify_energy_info, "papr_attributes");
+}
--
2.34.1

2022-02-18 00:15:25

by Pratik R. Sampat

[permalink] [raw]

Subject: [PATCH v9 1/2] powerpc/pseries: Interface to represent PAPR firmware attributes

Adds a syscall 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
);
As specified in PAPR+ v2.11, section 14.14.3.

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, flags = 1.

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 so that the firmware can add new values without the need for
the kernel to be changed.

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 <[email protected]>
---
.../sysfs-firmware-papr-energy-scale-info | 29 ++
arch/powerpc/include/asm/firmware.h | 4 +-
arch/powerpc/include/asm/hvcall.h | 3 +-
arch/powerpc/kvm/trace_hv.h | 1 +
arch/powerpc/platforms/pseries/Makefile | 3 +-
arch/powerpc/platforms/pseries/firmware.c | 1 +
.../pseries/papr_platform_attributes.c | 361 ++++++++++++++++++
7 files changed, 399 insertions(+), 3 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..141a6b371469
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-firmware-papr-energy-scale-info
@@ -0,0 +1,29 @@
+What: /sys/firmware/papr/energy_scale_info
+Date: February 2022
+Contact: Linux for PowerPC mailing list <[email protected]>
+Description: Directory hosting a set of platform attributes like
+ energy/frequency 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>
+Date: February 2022
+Contact: Linux for PowerPC mailing list <[email protected]>
+Description: Energy, frequency attributes directory for POWERVM servers
+
+What: /sys/firmware/papr/energy_scale_info/<id>/desc
+Date: February 2022
+Contact: Linux for PowerPC mailing list <[email protected]>
+Description: String description of the energy attribute of <id>
+
+What: /sys/firmware/papr/energy_scale_info/<id>/value
+Date: February 2022
+Contact: Linux for PowerPC mailing list <[email protected]>
+Description: Numeric value of the energy attribute of <id>
+
+What: /sys/firmware/papr/energy_scale_info/<id>/value_desc
+Date: February 2022
+Contact: Linux for PowerPC mailing list <[email protected]>
+Description: String value of the energy attribute of <id>
diff --git a/arch/powerpc/include/asm/firmware.h b/arch/powerpc/include/asm/firmware.h
index 9b702d2b80fb..8dddd34b8ecf 100644
--- a/arch/powerpc/include/asm/firmware.h
+++ b/arch/powerpc/include/asm/firmware.h
@@ -54,6 +54,7 @@
#define FW_FEATURE_STUFF_TCE ASM_CONST(0x0000008000000000)
#define FW_FEATURE_RPT_INVALIDATE ASM_CONST(0x0000010000000000)
#define FW_FEATURE_FORM2_AFFINITY ASM_CONST(0x0000020000000000)
+#define FW_FEATURE_ENERGY_SCALE_INFO ASM_CONST(0x0000040000000000)

#ifndef __ASSEMBLY__

@@ -74,7 +75,8 @@ enum {
FW_FEATURE_HPT_RESIZE | FW_FEATURE_DRMEM_V2 |
FW_FEATURE_DRC_INFO | FW_FEATURE_BLOCK_REMOVE |
FW_FEATURE_PAPR_SCM | FW_FEATURE_ULTRAVISOR |
- FW_FEATURE_RPT_INVALIDATE | FW_FEATURE_FORM2_AFFINITY,
+ FW_FEATURE_RPT_INVALIDATE | FW_FEATURE_FORM2_AFFINITY |
+ FW_FEATURE_ENERGY_SCALE_INFO,
FW_FEATURE_PSERIES_ALWAYS = 0,
FW_FEATURE_POWERNV_POSSIBLE = FW_FEATURE_OPAL | FW_FEATURE_ULTRAVISOR,
FW_FEATURE_POWERNV_ALWAYS = 0,
diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h
index 9bcf345cb208..48f510ba9f4a 100644
--- a/arch/powerpc/include/asm/hvcall.h
+++ b/arch/powerpc/include/asm/hvcall.h
@@ -323,7 +323,8 @@
#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)
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 ee60b59024b4..0489f84a609a 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_KEXEC_CORE) += kexec.o
obj-$(CONFIG_PSERIES_ENERGY) += pseries_energy.o
diff --git a/arch/powerpc/platforms/pseries/firmware.c b/arch/powerpc/platforms/pseries/firmware.c
index f162156b7b68..09c119b2f623 100644
--- a/arch/powerpc/platforms/pseries/firmware.c
+++ b/arch/powerpc/platforms/pseries/firmware.c
@@ -66,6 +66,7 @@ hypertas_fw_features_table[] = {
{FW_FEATURE_BLOCK_REMOVE, "hcall-block-remove"},
{FW_FEATURE_PAPR_SCM, "hcall-scm"},
{FW_FEATURE_RPT_INVALIDATE, "hcall-rpt-invalidate"},
+ {FW_FEATURE_ENERGY_SCALE_INFO, "hcall-energy-scale-info"},
};

/* Build up the firmware features bitmask using the contents of
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..515150417bb3
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/papr_platform_attributes.c
@@ -0,0 +1,361 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Platform energy and frequency attributes driver
+ *
+ * This driver creates a sys file at /sys/firmware/papr/ which encapsulates a
+ * directory structure containing files in keyword - value pairs that specify
+ * energy and frequency configuration of the system.
+ *
+ * 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)
+ *
+ * Copyright 2022 IBM Corp.
+ */
+
+#include <asm/hvcall.h>
+#include <asm/machdep.h>
+
+#include "pseries.h"
+
+/*
+ * Flag attributes to fetch either all or one attribute from the HCALL
+ * flag = BE(0) => fetch all attributes with firstAttributeId = 0
+ * flag = BE(1) => fetch a single attribute with firstAttributeId = id
+ */
+#define ESI_FLAGS_ALL 0
+#define ESI_FLAGS_SINGLE (1ull << 63)
+
+#define KOBJ_MAX_ATTRS 3
+
+#define ESI_HDR_SIZE sizeof(struct h_energy_scale_info_hdr)
+#define ESI_ATTR_SIZE sizeof(struct energy_scale_attribute)
+#define CURR_MAX_ESI_ATTRS 8
+
+struct energy_scale_attribute {
+ __be64 id;
+ __be64 val;
+ u8 desc[64];
+ u8 value_desc[64];
+} __packed;
+
+struct h_energy_scale_info_hdr {
+ __be64 num_attrs;
+ __be64 array_offset;
+ u8 data_header_version;
+} __packed;
+
+struct papr_attr {
+ u64 id;
+ struct kobj_attribute kobj_attr;
+};
+
+struct papr_group {
+ struct attribute_group pg;
+ struct papr_attr pgattrs[KOBJ_MAX_ATTRS];
+};
+
+static struct papr_group *papr_groups;
+/* /sys/firmware/papr */
+static struct kobject *papr_kobj;
+/* /sys/firmware/papr/energy_scale_info */
+static struct kobject *esi_kobj;
+
+/*
+ * Energy modes can change dynamically hence making a new hcall each time the
+ * information needs to be retrieved
+ */
+static int papr_get_attr(u64 id, struct energy_scale_attribute *esi)
+{
+ int esi_buf_size = ESI_HDR_SIZE + (CURR_MAX_ESI_ATTRS * ESI_ATTR_SIZE);
+ int ret, max_esi_attrs = CURR_MAX_ESI_ATTRS;
+ struct energy_scale_attribute *curr_esi;
+ struct h_energy_scale_info_hdr *hdr;
+ char *buf;
+
+ buf = kmalloc(esi_buf_size, GFP_KERNEL);
+ if (buf == NULL)
+ return -ENOMEM;
+
+retry:
+ ret = plpar_hcall_norets(H_GET_ENERGY_SCALE_INFO, ESI_FLAGS_SINGLE,
+ id, virt_to_phys(buf),
+ esi_buf_size);
+
+ /*
+ * If the hcall fails with not enough memory for either the
+ * header or data, attempt to allocate more
+ */
+ if (ret == H_PARTIAL || ret == H_P4) {
+ char *temp_buf;
+
+ max_esi_attrs += 4;
+ esi_buf_size = ESI_HDR_SIZE + (CURR_MAX_ESI_ATTRS * max_esi_attrs);
+
+ temp_buf = krealloc(buf, esi_buf_size, GFP_KERNEL);
+ if (temp_buf)
+ buf = temp_buf;
+ else
+ return -ENOMEM;
+
+ goto retry;
+ }
+
+ if (ret != H_SUCCESS) {
+ pr_warn("hcall failed: H_GET_ENERGY_SCALE_INFO");
+ ret = -EIO;
+ goto out_buf;
+ }
+
+ hdr = (struct h_energy_scale_info_hdr *) buf;
+ curr_esi = (struct energy_scale_attribute *)
+ (buf + be64_to_cpu(hdr->array_offset));
+
+ if (esi_buf_size <
+ be64_to_cpu(hdr->array_offset) + (be64_to_cpu(hdr->num_attrs)
+ * sizeof(struct energy_scale_attribute))) {
+ ret = -EIO;
+ goto out_buf;
+ }
+
+ *esi = *curr_esi;
+
+out_buf:
+ kfree(buf);
+
+ return ret;
+}
+
+/*
+ * Extract and export the description of the energy scale attributes
+ */
+static ssize_t desc_show(struct kobject *kobj,
+ struct kobj_attribute *kobj_attr,
+ char *buf)
+{
+ struct papr_attr *pattr = container_of(kobj_attr, struct papr_attr,
+ kobj_attr);
+ struct energy_scale_attribute esi;
+ int ret;
+
+ ret = papr_get_attr(pattr->id, &esi);
+ if (ret)
+ return ret;
+
+ return sysfs_emit(buf, "%s\n", esi.desc);
+}
+
+/*
+ * Extract and export the numeric value of the energy scale attributes
+ */
+static ssize_t val_show(struct kobject *kobj,
+ struct kobj_attribute *kobj_attr,
+ char *buf)
+{
+ struct papr_attr *pattr = container_of(kobj_attr, struct papr_attr,
+ kobj_attr);
+ struct energy_scale_attribute esi;
+ int ret;
+
+ ret = papr_get_attr(pattr->id, &esi);
+ if (ret)
+ return ret;
+
+ return sysfs_emit(buf, "%llu\n", be64_to_cpu(esi.val));
+}
+
+/*
+ * Extract and export the value description in string format of the energy
+ * scale attributes
+ */
+static ssize_t val_desc_show(struct kobject *kobj,
+ struct kobj_attribute *kobj_attr,
+ char *buf)
+{
+ struct papr_attr *pattr = container_of(kobj_attr, struct papr_attr,
+ kobj_attr);
+ struct energy_scale_attribute esi;
+ int ret;
+
+ ret = papr_get_attr(pattr->id, &esi);
+ if (ret)
+ return ret;
+
+ return sysfs_emit(buf, "%s\n", esi.value_desc);
+}
+
+static struct papr_ops_info {
+ const char *attr_name;
+ ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *kobj_attr,
+ char *buf);
+} ops_info[KOBJ_MAX_ATTRS] = {
+ { "desc", desc_show },
+ { "value", val_show },
+ { "value_desc", val_desc_show },
+};
+
+static void add_attr(u64 id, int index, struct papr_attr *attr)
+{
+ attr->id = id;
+ sysfs_attr_init(&attr->kobj_attr.attr);
+ attr->kobj_attr.attr.name = ops_info[index].attr_name;
+ attr->kobj_attr.attr.mode = 0444;
+ attr->kobj_attr.show = ops_info[index].show;
+}
+
+static int add_attr_group(u64 id, struct papr_group *pg, bool show_val_desc)
+{
+ int i;
+
+ for (i = 0; i < KOBJ_MAX_ATTRS; 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].kobj_attr.attr;
+ }
+
+ return sysfs_create_group(esi_kobj, &pg->pg);
+}
+
+
+static int __init papr_init(void)
+{
+ int esi_buf_size = ESI_HDR_SIZE + (CURR_MAX_ESI_ATTRS * ESI_ATTR_SIZE);
+ int ret, idx, i, max_esi_attrs = CURR_MAX_ESI_ATTRS;
+ struct h_energy_scale_info_hdr *esi_hdr;
+ struct energy_scale_attribute *esi_attrs;
+ uint64_t num_attrs;
+ char *esi_buf;
+
+ if (!firmware_has_feature(FW_FEATURE_LPAR) ||
+ !firmware_has_feature(FW_FEATURE_ENERGY_SCALE_INFO)) {
+ return -ENXIO;
+ }
+
+ esi_buf = kmalloc(esi_buf_size, GFP_KERNEL);
+ if (esi_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
+ */
+retry:
+
+ ret = plpar_hcall_norets(H_GET_ENERGY_SCALE_INFO, ESI_FLAGS_ALL, 0,
+ virt_to_phys(esi_buf), esi_buf_size);
+
+ /*
+ * If the hcall fails with not enough memory for either the
+ * header or data, attempt to allocate more
+ */
+ if (ret == H_PARTIAL || ret == H_P4) {
+ char *temp_esi_buf;
+
+ max_esi_attrs += 4;
+ esi_buf_size = ESI_HDR_SIZE + (CURR_MAX_ESI_ATTRS * max_esi_attrs);
+
+ temp_esi_buf = krealloc(esi_buf, esi_buf_size, GFP_KERNEL);
+ if (temp_esi_buf)
+ esi_buf = temp_esi_buf;
+ else
+ return -ENOMEM;
+
+ goto retry;
+ }
+
+ if (ret != H_SUCCESS) {
+ pr_warn("hcall failed: H_GET_ENERGY_SCALE_INFO, ret: %d\n", ret);
+ goto out_free_esi_buf;
+ }
+
+ esi_hdr = (struct h_energy_scale_info_hdr *) esi_buf;
+ num_attrs = be64_to_cpu(esi_hdr->num_attrs);
+ esi_attrs = (struct energy_scale_attribute *)
+ (esi_buf + be64_to_cpu(esi_hdr->array_offset));
+
+ if (esi_buf_size <
+ be64_to_cpu(esi_hdr->array_offset) +
+ (num_attrs * sizeof(struct energy_scale_attribute))) {
+ goto out_free_esi_buf;
+ }
+
+ papr_groups = kcalloc(num_attrs, sizeof(*papr_groups), GFP_KERNEL);
+ if (!papr_groups)
+ goto out_free_esi_buf;
+
+ papr_kobj = kobject_create_and_add("papr", firmware_kobj);
+ if (!papr_kobj) {
+ pr_warn("kobject_create_and_add papr failed\n");
+ goto out_papr_groups;
+ }
+
+ esi_kobj = kobject_create_and_add("energy_scale_info", papr_kobj);
+ if (!esi_kobj) {
+ pr_warn("kobject_create_and_add energy_scale_info failed\n");
+ goto out_kobj;
+ }
+
+ /* Allocate the groups before registering */
+ for (idx = 0; idx < num_attrs; idx++) {
+ papr_groups[idx].pg.attrs = kcalloc(KOBJ_MAX_ATTRS + 1,
+ sizeof(*papr_groups[idx].pg.attrs),
+ GFP_KERNEL);
+ if (!papr_groups[idx].pg.attrs)
+ goto out_pgattrs;
+
+ papr_groups[idx].pg.name = kasprintf(GFP_KERNEL, "%lld",
+ be64_to_cpu(esi_attrs[idx].id));
+ if (papr_groups[idx].pg.name == NULL)
+ goto out_pgattrs;
+ }
+
+ for (idx = 0; idx < num_attrs; idx++) {
+ bool show_val_desc = true;
+
+ /* Do not add the value desc attr if it does not exist */
+ if (strnlen(esi_attrs[idx].value_desc,
+ sizeof(esi_attrs[idx].value_desc)) == 0)
+ show_val_desc = false;
+
+ if (add_attr_group(be64_to_cpu(esi_attrs[idx].id),
+ &papr_groups[idx],
+ show_val_desc)) {
+ pr_warn("Failed to create papr attribute group %s\n",
+ papr_groups[idx].pg.name);
+ idx = num_attrs;
+ goto out_pgattrs;
+ }
+ }
+
+ kfree(esi_buf);
+ return 0;
+out_pgattrs:
+ for (i = 0; i < idx ; i++) {
+ kfree(papr_groups[i].pg.attrs);
+ kfree(papr_groups[i].pg.name);
+ }
+ kobject_put(esi_kobj);
+out_kobj:
+ kobject_put(papr_kobj);
+out_papr_groups:
+ kfree(papr_groups);
+out_free_esi_buf:
+ kfree(esi_buf);
+
+ return -ENOMEM;
+}
+
+machine_device_initcall(pseries, papr_init);
--
2.34.1

2022-03-08 13:18:08

by Michael Ellerman

[permalink] [raw]

Subject: Re: [PATCH v9 0/2] Interface to represent PAPR firmware attributes