lkml.org 
[lkml]   [2016]   [Oct]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v4 12/18] x86/intel_rdt: Add "info" files to resctrl file system
Date
From: Fenghua Yu <fenghua.yu@intel.com>

For the convenience of applications we make the decoded values of some
of the CPUID values available in read-only (0444) files.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
---
arch/x86/include/asm/intel_rdt.h | 24 +++++
arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 175 ++++++++++++++++++++++++++++++-
2 files changed, 198 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/intel_rdt.h b/arch/x86/include/asm/intel_rdt.h
index f7acae2..ea8c09b3 100644
--- a/arch/x86/include/asm/intel_rdt.h
+++ b/arch/x86/include/asm/intel_rdt.h
@@ -22,6 +22,30 @@ extern struct list_head rdt_all_groups;
int __init rdtgroup_init(void);

/**
+ * struct rftype - describe each file in the resctrl file system
+ * @name: file name
+ * @mode: access mode
+ * @kf_ops: operations
+ * @seq_show: show content of the file
+ * @write: write to the file
+ */
+struct rftype {
+ char *name;
+ umode_t mode;
+ struct kernfs_ops *kf_ops;
+
+ int (*seq_show)(struct kernfs_open_file *of,
+ struct seq_file *sf, void *v);
+ /*
+ * write() is the generic write callback which maps directly to
+ * kernfs write operation and overrides all other operations.
+ * Maximum write size is determined by ->max_write_len.
+ */
+ ssize_t (*write)(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off);
+};
+
+/**
* struct rdt_resource - attributes of an RDT resource
* @enabled: Is this feature enabled on this machine
* @name: Name to use in "schemata" file
diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
index b2bbd04..316fa0c 100644
--- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
+++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
@@ -23,6 +23,8 @@
#include <linux/fs.h>
#include <linux/sysfs.h>
#include <linux/kernfs.h>
+#include <linux/seq_file.h>
+#include <linux/sched.h>
#include <linux/slab.h>

#include <uapi/linux/magic.h>
@@ -34,6 +36,173 @@ struct kernfs_root *rdt_root;
struct rdtgroup rdtgroup_default;
LIST_HEAD(rdt_all_groups);

+/* set uid and gid of rdtgroup dirs and files to that of the creator */
+static int rdtgroup_kn_set_ugid(struct kernfs_node *kn)
+{
+ struct iattr iattr = { .ia_valid = ATTR_UID | ATTR_GID,
+ .ia_uid = current_fsuid(),
+ .ia_gid = current_fsgid(), };
+
+ if (uid_eq(iattr.ia_uid, GLOBAL_ROOT_UID) &&
+ gid_eq(iattr.ia_gid, GLOBAL_ROOT_GID))
+ return 0;
+
+ return kernfs_setattr(kn, &iattr);
+}
+
+static int rdtgroup_add_file(struct kernfs_node *parent_kn, struct rftype *rft)
+{
+ struct kernfs_node *kn;
+ int ret;
+
+ kn = __kernfs_create_file(parent_kn, rft->name, rft->mode,
+ 0, rft->kf_ops, rft, NULL, NULL);
+ if (IS_ERR(kn))
+ return PTR_ERR(kn);
+
+ ret = rdtgroup_kn_set_ugid(kn);
+ if (ret) {
+ kernfs_remove(kn);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int rdtgroup_add_files(struct kernfs_node *kn, struct rftype *rfts)
+{
+ struct rftype *rft;
+ int ret;
+
+ lockdep_assert_held(&rdtgroup_mutex);
+
+ for (rft = rfts; rft->name; rft++) {
+ ret = rdtgroup_add_file(kn, rft);
+ if (ret)
+ goto error;
+ }
+
+ return 0;
+error:
+ pr_warn("%s: failed to add %s, err=%d\n", __func__, rft->name, ret);
+ while (--rft >= rfts)
+ kernfs_remove_by_name(kn, rft->name);
+ return ret;
+}
+
+static int rdtgroup_seqfile_show(struct seq_file *m, void *arg)
+{
+ struct kernfs_open_file *of = m->private;
+ struct rftype *rft = of->kn->priv;
+
+ if (rft->seq_show)
+ return rft->seq_show(of, m, arg);
+ return 0;
+}
+
+static ssize_t rdtgroup_file_write(struct kernfs_open_file *of, char *buf,
+ size_t nbytes, loff_t off)
+{
+ struct rftype *rft = of->kn->priv;
+
+ if (rft->write)
+ return rft->write(of, buf, nbytes, off);
+
+ return -EINVAL;
+}
+
+static struct kernfs_ops rdtgroup_kf_single_ops = {
+ .atomic_write_len = PAGE_SIZE,
+ .write = rdtgroup_file_write,
+ .seq_show = rdtgroup_seqfile_show,
+};
+
+static int rdt_num_closid_show(struct kernfs_open_file *of,
+ struct seq_file *seq, void *v)
+{
+ struct rdt_resource *r = of->kn->parent->priv;
+
+ seq_printf(seq, "%d\n", r->num_closid);
+
+ return 0;
+}
+
+static int rdt_cbm_val_show(struct kernfs_open_file *of,
+ struct seq_file *seq, void *v)
+{
+ struct rdt_resource *r = of->kn->parent->priv;
+
+ seq_printf(seq, "%x\n", r->max_cbm);
+
+ return 0;
+}
+
+/* rdtgroup information files for one cache resource. */
+static struct rftype res_info_files[] = {
+ {
+ .name = "num_closid",
+ .mode = 0444,
+ .kf_ops = &rdtgroup_kf_single_ops,
+ .seq_show = rdt_num_closid_show,
+ },
+ {
+ .name = "cbm_val",
+ .mode = 0444,
+ .kf_ops = &rdtgroup_kf_single_ops,
+ .seq_show = rdt_cbm_val_show,
+ },
+ {
+ /* NULL terminated */
+ }
+};
+
+static int rdtgroup_create_info_dir(struct kernfs_node *parent_kn)
+{
+ struct kernfs_node *kn, *kn_subdir;
+ struct rdt_resource *r;
+ int ret;
+
+ /* create the directory */
+ kn = kernfs_create_dir(parent_kn, "info", parent_kn->mode, NULL);
+ if (IS_ERR(kn))
+ return PTR_ERR(kn);
+ kernfs_get(kn);
+
+ for_each_rdt_resource(r) {
+ kn_subdir = kernfs_create_dir(kn, r->name, kn->mode, r);
+ if (IS_ERR(kn_subdir)) {
+ ret = PTR_ERR(kn_subdir);
+ goto out_destroy;
+ }
+ kernfs_get(kn_subdir);
+ ret = rdtgroup_kn_set_ugid(kn_subdir);
+ if (ret)
+ goto out_destroy;
+ ret = rdtgroup_add_files(kn_subdir, res_info_files);
+ if (ret)
+ goto out_destroy;
+ kernfs_activate(kn_subdir);
+ }
+
+ /*
+ * This extra ref will be put in kernfs_remove() and guarantees
+ * that @rdtgrp->kn is always accessible.
+ */
+ kernfs_get(kn);
+
+ ret = rdtgroup_kn_set_ugid(kn);
+ if (ret)
+ goto out_destroy;
+
+ kernfs_activate(kn);
+
+ return 0;
+
+out_destroy:
+ kernfs_remove(kn);
+ return ret;
+}
+
static void l3_qos_cfg_update(void *arg)
{
struct rdt_resource *r = arg;
@@ -181,6 +350,8 @@ static struct kernfs_syscall_ops rdtgroup_kf_syscall_ops = {

static int __init rdtgroup_setup_root(void)
{
+ int ret;
+
rdt_root = kernfs_create_root(&rdtgroup_kf_syscall_ops,
KERNFS_ROOT_CREATE_DEACTIVATED,
&rdtgroup_default);
@@ -193,7 +364,9 @@ static int __init rdtgroup_setup_root(void)
list_add(&rdtgroup_default.rdtgroup_list, &rdt_all_groups);

rdtgroup_default.kn = rdt_root->kn;
- kernfs_activate(rdtgroup_default.kn);
+ ret = rdtgroup_create_info_dir(rdtgroup_default.kn);
+ if (!ret)
+ kernfs_activate(rdtgroup_default.kn);

mutex_unlock(&rdtgroup_mutex);

--
2.5.0
\
 
 \ /
  Last update: 2016-10-15 01:15    [W:0.260 / U:5.104 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site