2 * Resource Director Technology(RDT)
3 * - Cache Allocation code.
5 * Copyright (C) 2016 Intel Corporation
8 * Fenghua Yu <fenghua.yu@intel.com>
9 * Tony Luck <tony.luck@intel.com>
11 * This program is free software; you can redistribute it and/or modify it
12 * under the terms and conditions of the GNU General Public License,
13 * version 2, as published by the Free Software Foundation.
15 * This program is distributed in the hope it will be useful, but WITHOUT
16 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
17 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
20 * More information about RDT be found in the Intel (R) x86 Architecture
21 * Software Developer Manual June 2016, volume 3, section 17.17.
24 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
26 #include <linux/kernfs.h>
27 #include <linux/seq_file.h>
28 #include <linux/slab.h>
29 #include <asm/intel_rdt.h>
32 * Check whether a cache bit mask is valid. The SDM says:
33 * Please note that all (and only) contiguous '1' combinations
34 * are allowed (e.g. FFFFH, 0FF0H, 003CH, etc.).
35 * Additionally Haswell requires at least two bits set.
37 static bool cbm_validate(unsigned long var, struct rdt_resource *r)
39 unsigned long first_bit, zero_bit;
40 unsigned int cbm_len = r->cache.cbm_len;
42 if (var == 0 || var > r->default_ctrl)
45 first_bit = find_first_bit(&var, cbm_len);
46 zero_bit = find_next_zero_bit(&var, cbm_len, first_bit);
48 if (find_next_bit(&var, cbm_len, zero_bit) < cbm_len)
51 if ((zero_bit - first_bit) < r->cache.min_cbm_bits)
57 * Read one cache bit mask (hex). Check that it is valid for the current
60 static int parse_cbm(char *buf, struct rdt_resource *r, struct rdt_domain *d)
68 ret = kstrtoul(buf, 16, &data);
71 if (!cbm_validate(data, r))
74 d->have_new_ctrl = true;
80 * For each domain in this resource we expect to find a series of:
82 * separated by ";". The "id" is in decimal, and must match one of
83 * the "id"s for this resource.
85 static int parse_line(char *line, struct rdt_resource *r)
87 char *dom = NULL, *id;
92 if (!line || line[0] == '\0')
94 dom = strsep(&line, ";");
95 id = strsep(&dom, "=");
96 if (!dom || kstrtoul(id, 10, &dom_id))
98 list_for_each_entry(d, &r->domains, list) {
99 if (d->id == dom_id) {
100 if (parse_cbm(dom, r, d))
108 static int update_domains(struct rdt_resource *r, int closid)
110 struct msr_param msr_param;
111 cpumask_var_t cpu_mask;
112 struct rdt_domain *d;
115 if (!zalloc_cpumask_var(&cpu_mask, GFP_KERNEL))
118 msr_param.low = closid;
119 msr_param.high = msr_param.low + 1;
122 list_for_each_entry(d, &r->domains, list) {
123 if (d->have_new_ctrl && d->new_ctrl != d->ctrl_val[closid]) {
124 cpumask_set_cpu(cpumask_any(&d->cpu_mask), cpu_mask);
125 d->ctrl_val[closid] = d->new_ctrl;
128 if (cpumask_empty(cpu_mask))
131 /* Update CBM on this cpu if it's in cpu_mask. */
132 if (cpumask_test_cpu(cpu, cpu_mask))
133 rdt_ctrl_update(&msr_param);
134 /* Update CBM on other cpus. */
135 smp_call_function_many(cpu_mask, rdt_ctrl_update, &msr_param, 1);
139 free_cpumask_var(cpu_mask);
144 ssize_t rdtgroup_schemata_write(struct kernfs_open_file *of,
145 char *buf, size_t nbytes, loff_t off)
147 struct rdtgroup *rdtgrp;
148 struct rdt_domain *dom;
149 struct rdt_resource *r;
153 /* Valid input requires a trailing newline */
154 if (nbytes == 0 || buf[nbytes - 1] != '\n')
156 buf[nbytes - 1] = '\0';
158 rdtgrp = rdtgroup_kn_lock_live(of->kn);
160 rdtgroup_kn_unlock(of->kn);
164 closid = rdtgrp->closid;
166 for_each_enabled_rdt_resource(r)
167 list_for_each_entry(dom, &r->domains, list)
168 dom->have_new_ctrl = false;
170 while ((tok = strsep(&buf, "\n")) != NULL) {
171 resname = strsep(&tok, ":");
176 for_each_enabled_rdt_resource(r) {
177 if (!strcmp(resname, r->name) &&
178 closid < r->num_closid) {
179 ret = parse_line(tok, r);
191 for_each_enabled_rdt_resource(r) {
192 ret = update_domains(r, closid);
198 rdtgroup_kn_unlock(of->kn);
199 return ret ?: nbytes;
202 static void show_doms(struct seq_file *s, struct rdt_resource *r, int closid)
204 struct rdt_domain *dom;
207 seq_printf(s, "%*s:", max_name_width, r->name);
208 list_for_each_entry(dom, &r->domains, list) {
211 seq_printf(s, "%d=%0*x", dom->id, max_data_width,
212 dom->ctrl_val[closid]);
218 int rdtgroup_schemata_show(struct kernfs_open_file *of,
219 struct seq_file *s, void *v)
221 struct rdtgroup *rdtgrp;
222 struct rdt_resource *r;
225 rdtgrp = rdtgroup_kn_lock_live(of->kn);
227 closid = rdtgrp->closid;
228 for_each_enabled_rdt_resource(r) {
229 if (closid < r->num_closid)
230 show_doms(s, r, closid);
235 rdtgroup_kn_unlock(of->kn);