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x86/intel_rdt: Add "info" files to resctrl file system 

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>
Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: "Shaohua Li" <shli@fb.com>
Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com>
Cc: "Peter Zijlstra" <peterz@infradead.org>
Cc: "Stephane Eranian" <eranian@google.com>
Cc: "Dave Hansen" <dave.hansen@intel.com>
Cc: "David Carrillo-Cisneros" <davidcc@google.com>
Cc: "Nilay Vaish" <nilayvaish@gmail.com>
Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com>
Cc: "Ingo Molnar" <mingo@elte.hu>
Cc: "Borislav Petkov" <bp@suse.de>
Cc: "H. Peter Anvin" <h.peter.anvin@intel.com>
Link: http://lkml.kernel.org/r/1477692289-37412-5-git-send-email-fenghua.yu@intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
hifive-unleashed-5.1
Fenghua Yu 2016-10-28 15:04:43 -07:00 committed by Thomas Gleixner
parent 5ff193fbde
commit 4e978d06de
2 changed files with 209 additions and 0 deletions
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24
arch/x86/include/asm/intel_rdt.h
View File

@ -26,6 +26,30 @@ 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

185
arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
View File

@ -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;
@ -137,6 +309,10 @@ static struct dentry *rdt_mount(struct file_system_type *fs_type,
goto out_cdp;
}
ret = rdtgroup_create_info_dir(rdtgroup_default.kn);
if (ret)
goto out_cdp;
dentry = kernfs_mount(fs_type, flags, rdt_root,
RDTGROUP_SUPER_MAGIC, NULL);
if (IS_ERR(dentry))
@ -191,6 +367,14 @@ 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;
@ -201,6 +385,7 @@ static void rdt_kill_sb(struct super_block *sb)
for_each_enabled_rdt_resource(r)
reset_all_cbms(r);
cdp_disable();
rmdir_all_sub();
static_branch_disable(&rdt_enable_key);
kernfs_kill_sb(sb);
mutex_unlock(&rdtgroup_mutex);