/*
 * Resource Director Technology(RDT)
 * - Cache Allocation code.
 *
 * Copyright (C) 2016 Intel Corporation
 *
 * Authors:
 *    Fenghua Yu <fenghua.yu@intel.com>
 *    Tony Luck <tony.luck@intel.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * More information about RDT be found in the Intel (R) x86 Architecture
 * Software Developer Manual June 2016, volume 3, section 17.17.
 */

#define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt

#include <linux/kernfs.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include "intel_rdt.h"

/*
 * Check whether MBA bandwidth percentage value is correct. The value is
 * checked against the minimum and max bandwidth values specified by the
 * hardware. The allocated bandwidth percentage is rounded to the next
 * control step available on the hardware.
 */
static bool bw_validate(char *buf, unsigned long *data, struct rdt_resource *r)
{
        unsigned long bw;
        int ret;

        /*
         * Only linear delay values is supported for current Intel SKUs.
         */
        if (!r->membw.delay_linear) {
                rdt_last_cmd_puts("No support for non-linear MB domains\n");
                return false;
        }

        ret = kstrtoul(buf, 10, &bw);
        if (ret) {
                rdt_last_cmd_printf("Non-decimal digit in MB value %s\n", buf);
                return false;
        }

        if ((bw < r->membw.min_bw || bw > r->default_ctrl) &&
            !is_mba_sc(r)) {
                rdt_last_cmd_printf("MB value %ld out of range [%d,%d]\n", bw,
                                    r->membw.min_bw, r->default_ctrl);
                return false;
        }

        *data = roundup(bw, (unsigned long)r->membw.bw_gran);
        return true;
}

int parse_bw(struct rdt_parse_data *data, struct rdt_resource *r,
             struct rdt_domain *d)
{
        unsigned long bw_val;

        if (d->have_new_ctrl) {
                rdt_last_cmd_printf("duplicate domain %d\n", d->id);
                return -EINVAL;
        }

        if (!bw_validate(data->buf, &bw_val, r))
                return -EINVAL;
        d->new_ctrl = bw_val;
        d->have_new_ctrl = true;

        return 0;
}

/*
 * Check whether a cache bit mask is valid. The SDM says:
 *      Please note that all (and only) contiguous '1' combinations
 *      are allowed (e.g. FFFFH, 0FF0H, 003CH, etc.).
 * Additionally Haswell requires at least two bits set.
 */
static bool cbm_validate(char *buf, u32 *data, struct rdt_resource *r)
{
        unsigned long first_bit, zero_bit, val;
        unsigned int cbm_len = r->cache.cbm_len;
        int ret;

        ret = kstrtoul(buf, 16, &val);
        if (ret) {
                rdt_last_cmd_printf("non-hex character in mask %s\n", buf);
                return false;
        }

        if (val == 0 || val > r->default_ctrl) {
                rdt_last_cmd_puts("mask out of range\n");
                return false;
        }

        first_bit = find_first_bit(&val, cbm_len);
        zero_bit = find_next_zero_bit(&val, cbm_len, first_bit);

        if (find_next_bit(&val, cbm_len, zero_bit) < cbm_len) {
                rdt_last_cmd_printf("mask %lx has non-consecutive 1-bits\n", val);
                return false;
        }

        if ((zero_bit - first_bit) < r->cache.min_cbm_bits) {
                rdt_last_cmd_printf("Need at least %d bits in mask\n",
                                    r->cache.min_cbm_bits);
                return false;
        }

        *data = val;
        return true;
}

/*
 * Read one cache bit mask (hex). Check that it is valid for the current
 * resource type.
 */
int parse_cbm(struct rdt_parse_data *data, struct rdt_resource *r,
              struct rdt_domain *d)
{
        struct rdtgroup *rdtgrp = data->rdtgrp;
        u32 cbm_val;

        if (d->have_new_ctrl) {
                rdt_last_cmd_printf("duplicate domain %d\n", d->id);
                return -EINVAL;
        }

        /*
         * Cannot set up more than one pseudo-locked region in a cache
         * hierarchy.
         */
        if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP &&
            rdtgroup_pseudo_locked_in_hierarchy(d)) {
                rdt_last_cmd_printf("pseudo-locked region in hierarchy\n");
                return -EINVAL;
        }

        if (!cbm_validate(data->buf, &cbm_val, r))
                return -EINVAL;

        if ((rdtgrp->mode == RDT_MODE_EXCLUSIVE ||
             rdtgrp->mode == RDT_MODE_SHAREABLE) &&
            rdtgroup_cbm_overlaps_pseudo_locked(d, cbm_val)) {
                rdt_last_cmd_printf("CBM overlaps with pseudo-locked region\n");
                return -EINVAL;
        }

        /*
         * The CBM may not overlap with the CBM of another closid if
         * either is exclusive.
         */
        if (rdtgroup_cbm_overlaps(r, d, cbm_val, rdtgrp->closid, true)) {
                rdt_last_cmd_printf("overlaps with exclusive group\n");
                return -EINVAL;
        }

        if (rdtgroup_cbm_overlaps(r, d, cbm_val, rdtgrp->closid, false)) {
                if (rdtgrp->mode == RDT_MODE_EXCLUSIVE ||
                    rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
                        rdt_last_cmd_printf("overlaps with other group\n");
                        return -EINVAL;
                }
        }

        d->new_ctrl = cbm_val;
        d->have_new_ctrl = true;

        return 0;
}

/*
 * For each domain in this resource we expect to find a series of:
 *      id=mask
 * separated by ";". The "id" is in decimal, and must match one of
 * the "id"s for this resource.
 */
static int parse_line(char *line, struct rdt_resource *r,
                      struct rdtgroup *rdtgrp)
{
        struct rdt_parse_data data;
        char *dom = NULL, *id;
        struct rdt_domain *d;
        unsigned long dom_id;

        if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP &&
            r->rid == RDT_RESOURCE_MBA) {
                rdt_last_cmd_puts("Cannot pseudo-lock MBA resource\n");
                return -EINVAL;
        }

next:
        if (!line || line[0] == '\0')
                return 0;
        dom = strsep(&line, ";");
        id = strsep(&dom, "=");
        if (!dom || kstrtoul(id, 10, &dom_id)) {
                rdt_last_cmd_puts("Missing '=' or non-numeric domain\n");
                return -EINVAL;
        }
        dom = strim(dom);
        list_for_each_entry(d, &r->domains, list) {
                if (d->id == dom_id) {
                        data.buf = dom;
                        data.rdtgrp = rdtgrp;
                        if (r->parse_ctrlval(&data, r, d))
                                return -EINVAL;
                        if (rdtgrp->mode ==  RDT_MODE_PSEUDO_LOCKSETUP) {
                                /*
                                 * In pseudo-locking setup mode and just
                                 * parsed a valid CBM that should be
                                 * pseudo-locked. Only one locked region per
                                 * resource group and domain so just do
                                 * the required initialization for single
                                 * region and return.
                                 */
                                rdtgrp->plr->r = r;
                                rdtgrp->plr->d = d;
                                rdtgrp->plr->cbm = d->new_ctrl;
                                d->plr = rdtgrp->plr;
                                return 0;
                        }
                        goto next;
                }
        }
        return -EINVAL;
}

int update_domains(struct rdt_resource *r, int closid)
{
        struct msr_param msr_param;
        cpumask_var_t cpu_mask;
        struct rdt_domain *d;
        bool mba_sc;
        u32 *dc;
        int cpu;

        if (!zalloc_cpumask_var(&cpu_mask, GFP_KERNEL))
                return -ENOMEM;

        msr_param.low = closid;
        msr_param.high = msr_param.low + 1;
        msr_param.res = r;

        mba_sc = is_mba_sc(r);
        list_for_each_entry(d, &r->domains, list) {
                dc = !mba_sc ? d->ctrl_val : d->mbps_val;
                if (d->have_new_ctrl && d->new_ctrl != dc[closid]) {
                        cpumask_set_cpu(cpumask_any(&d->cpu_mask), cpu_mask);
                        dc[closid] = d->new_ctrl;
                }
        }

        /*
         * Avoid writing the control msr with control values when
         * MBA software controller is enabled
         */
        if (cpumask_empty(cpu_mask) || mba_sc)
                goto done;
        cpu = get_cpu();
        /* Update CBM on this cpu if it's in cpu_mask. */
        if (cpumask_test_cpu(cpu, cpu_mask))
                rdt_ctrl_update(&msr_param);
        /* Update CBM on other cpus. */
        smp_call_function_many(cpu_mask, rdt_ctrl_update, &msr_param, 1);
        put_cpu();

done:
        free_cpumask_var(cpu_mask);

        return 0;
}

static int rdtgroup_parse_resource(char *resname, char *tok,
                                   struct rdtgroup *rdtgrp)
{
        struct rdt_resource *r;

        for_each_alloc_enabled_rdt_resource(r) {
                if (!strcmp(resname, r->name) && rdtgrp->closid < r->num_closid)
                        return parse_line(tok, r, rdtgrp);
        }
        rdt_last_cmd_printf("unknown/unsupported resource name '%s'\n", resname);
        return -EINVAL;
}

ssize_t rdtgroup_schemata_write(struct kernfs_open_file *of,
                                char *buf, size_t nbytes, loff_t off)
{
        struct rdtgroup *rdtgrp;
        struct rdt_domain *dom;
        struct rdt_resource *r;
        char *tok, *resname;
        int ret = 0;

        /* Valid input requires a trailing newline */
        if (nbytes == 0 || buf[nbytes - 1] != '\n')
                return -EINVAL;
        buf[nbytes - 1] = '\0';

        rdtgrp = rdtgroup_kn_lock_live(of->kn);
        if (!rdtgrp) {
                rdtgroup_kn_unlock(of->kn);
                return -ENOENT;
        }
        rdt_last_cmd_clear();

        /*
         * No changes to pseudo-locked region allowed. It has to be removed
         * and re-created instead.
         */
        if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED) {
                ret = -EINVAL;
                rdt_last_cmd_puts("resource group is pseudo-locked\n");
                goto out;
        }

        for_each_alloc_enabled_rdt_resource(r) {
                list_for_each_entry(dom, &r->domains, list)
                        dom->have_new_ctrl = false;
        }

        while ((tok = strsep(&buf, "\n")) != NULL) {
                resname = strim(strsep(&tok, ":"));
                if (!tok) {
                        rdt_last_cmd_puts("Missing ':'\n");
                        ret = -EINVAL;
                        goto out;
                }
                if (tok[0] == '\0') {
                        rdt_last_cmd_printf("Missing '%s' value\n", resname);
                        ret = -EINVAL;
                        goto out;
                }
                ret = rdtgroup_parse_resource(resname, tok, rdtgrp);
                if (ret)
                        goto out;
        }

        for_each_alloc_enabled_rdt_resource(r) {
                ret = update_domains(r, rdtgrp->closid);
                if (ret)
                        goto out;
        }

        if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
                /*
                 * If pseudo-locking fails we keep the resource group in
                 * mode RDT_MODE_PSEUDO_LOCKSETUP with its class of service
                 * active and updated for just the domain the pseudo-locked
                 * region was requested for.
                 */
                ret = rdtgroup_pseudo_lock_create(rdtgrp);
        }

out:
        rdtgroup_kn_unlock(of->kn);
        return ret ?: nbytes;
}

static void show_doms(struct seq_file *s, struct rdt_resource *r, int closid)
{
        struct rdt_domain *dom;
        bool sep = false;
        u32 ctrl_val;

        seq_printf(s, "%*s:", max_name_width, r->name);
        list_for_each_entry(dom, &r->domains, list) {
                if (sep)
                        seq_puts(s, ";");

                ctrl_val = (!is_mba_sc(r) ? dom->ctrl_val[closid] :
                            dom->mbps_val[closid]);
                seq_printf(s, r->format_str, dom->id, max_data_width,
                           ctrl_val);
                sep = true;
        }
        seq_puts(s, "\n");
}

int rdtgroup_schemata_show(struct kernfs_open_file *of,
                           struct seq_file *s, void *v)
{
        struct rdtgroup *rdtgrp;
        struct rdt_resource *r;
        int ret = 0;
        u32 closid;

        rdtgrp = rdtgroup_kn_lock_live(of->kn);
        if (rdtgrp) {
                if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
                        for_each_alloc_enabled_rdt_resource(r)
                                seq_printf(s, "%s:uninitialized\n", r->name);
                } else if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED) {
                        seq_printf(s, "%s:%d=%x\n", rdtgrp->plr->r->name,
                                   rdtgrp->plr->d->id, rdtgrp->plr->cbm);
                } else {
                        closid = rdtgrp->closid;
                        for_each_alloc_enabled_rdt_resource(r) {
                                if (closid < r->num_closid)
                                        show_doms(s, r, closid);
                        }
                }
        } else {
                ret = -ENOENT;
        }
        rdtgroup_kn_unlock(of->kn);
        return ret;
}

void mon_event_read(struct rmid_read *rr, struct rdt_domain *d,
                    struct rdtgroup *rdtgrp, int evtid, int first)
{
        /*
         * setup the parameters to send to the IPI to read the data.
         */
        rr->rgrp = rdtgrp;
        rr->evtid = evtid;
        rr->d = d;
        rr->val = 0;
        rr->first = first;

        smp_call_function_any(&d->cpu_mask, mon_event_count, rr, 1);
}

int rdtgroup_mondata_show(struct seq_file *m, void *arg)
{
        struct kernfs_open_file *of = m->private;
        u32 resid, evtid, domid;
        struct rdtgroup *rdtgrp;
        struct rdt_resource *r;
        union mon_data_bits md;
        struct rdt_domain *d;
        struct rmid_read rr;
        int ret = 0;

        rdtgrp = rdtgroup_kn_lock_live(of->kn);

        md.priv = of->kn->priv;
        resid = md.u.rid;
        domid = md.u.domid;
        evtid = md.u.evtid;

        r = &rdt_resources_all[resid];
        d = rdt_find_domain(r, domid, NULL);
        if (!d) {
                ret = -ENOENT;
                goto out;
        }

        mon_event_read(&rr, d, rdtgrp, evtid, false);

        if (rr.val & RMID_VAL_ERROR)
                seq_puts(m, "Error\n");
        else if (rr.val & RMID_VAL_UNAVAIL)
                seq_puts(m, "Unavailable\n");
        else
                seq_printf(m, "%llu\n", rr.val * r->mon_scale);

out:
        rdtgroup_kn_unlock(of->kn);
        return ret;
}