diff --git a/arch/x86/include/asm/intel_rdt.h b/arch/x86/include/asm/intel_rdt.h index 09d00e6f7ad65122c5a520392ca36471463ed5d7..5b7b3f6f1f96b8e9190d196593f30814affa3032 100644 --- a/arch/x86/include/asm/intel_rdt.h +++ b/arch/x86/include/asm/intel_rdt.h @@ -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 diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c index 106e4ce8f7e04b5f3bc27f127691eb40263ad584..fbb42e79b10a02631322447df303443f2757b138 100644 --- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c +++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c @@ -23,6 +23,8 @@ #include #include #include +#include +#include #include #include @@ -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);