From: Fenghua Yu <fenghua...@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...@intel.com>
---
arch/x86/include/asm/intel_rdt.h | 24 ++++
arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 185 +++++++++++++++++++++++++++++++
2 files changed, 209 insertions(+)
diff --git a/arch/x86/include/asm/intel_rdt.h b/arch/x86/include/asm/intel_rdt.h
index 8e1d002..39ed561 100644
--- a/arch/x86/include/asm/intel_rdt.h
+++ b/arch/x86/include/asm/intel_rdt.h
@@ -25,6 +25,30 @@ 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
* @capable: Is this feature available on this machine
diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
index 74d7f72f..58aa8f7 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 +36,176 @@ struct kernfs_root *rdt_root;
struct rdtgroup rdtgroup_default;
LIST_HEAD(rdt_all_groups);
+/* Kernel fs node for "info" directory under root */
+static struct kernfs_node *kn_info;
+
+/* 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,
+ int len)
+{
+ struct rftype *rft;
+ int ret;
+
+ lockdep_assert_held(&rdtgroup_mutex);
+
+ for (rft = rfts; rft < rfts + len; rft++) {
+ ret = rdtgroup_add_file(kn, rft);
+ if (ret)
+ goto error;
+ }
+
+ return 0;
+error:
+ pr_warn("Failed to add %s, err=%d\n", 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_closids_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_mask_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_closids",
+ .mode = 0444,
+ .kf_ops = &rdtgroup_kf_single_ops,
+ .seq_show = rdt_num_closids_show,
+ },
+ {
+ .name = "cbm_mask",
+ .mode = 0444,
+ .kf_ops = &rdtgroup_kf_single_ops,
+ .seq_show = rdt_cbm_mask_show,
+ },
+};
+
+static int rdtgroup_create_info_dir(struct kernfs_node *parent_kn)
+{
+ struct kernfs_node *kn_subdir;
+ struct rdt_resource *r;
+ int ret;
+
+ /* create the directory */
+ kn_info = kernfs_create_dir(parent_kn, "info", parent_kn->mode, NULL);
+ if (IS_ERR(kn_info))
+ return PTR_ERR(kn_info);
+ kernfs_get(kn_info);
+
+ for_each_enabled_rdt_resource(r) {
+ kn_subdir = kernfs_create_dir(kn_info, r->name,
+ kn_info->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,
+ ARRAY_SIZE(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_info);
+
+ ret = rdtgroup_kn_set_ugid(kn_info);
+ if (ret)
+ goto out_destroy;
+
+ kernfs_activate(kn_info);
+
+ return 0;
+
+out_destroy:
+ kernfs_remove(kn_info);
+ return ret;
+}
+
static void l3_qos_cfg_update(void *arg)
{
bool *enable = arg;
@@ -130,6 +302,10 @@ static struct dentry *rdt_mount(struct file_system_type
*fs_type,
}
}
+ ret = rdtgroup_create_info_dir(rdtgroup_default.kn);
+ if (ret)
+ goto out;
+
dentry = kernfs_mount(fs_type, flags, rdt_root,
RDTGROUP_SUPER_MAGIC, NULL);
if (IS_ERR(dentry))
@@ -181,6 +357,14 @@ static int reset_all_cbms(struct rdt_resource *r)
return 0;
}
+/*
+ * Forcibly remove all of subdirectories under root.
+ */
+static void rmdir_all_sub(void)
+{
+ kernfs_remove(kn_info);
+}
+
static void rdt_kill_sb(struct super_block *sb)
{
struct rdt_resource *r;
@@ -198,6 +382,7 @@ static void rdt_kill_sb(struct super_block *sb)
set_l3_qos_cfg(r, false);
}
+ rmdir_all_sub();
static_branch_disable(&rdt_enable_key);
kernfs_kill_sb(sb);
mutex_unlock(&rdtgroup_mutex);
--
2.5.0
