Release 4.14 arch/powerpc/perf/hv-24x7.c

/*
 * Hypervisor supplied "24x7" performance counter support
 *
 * Author: Cody P Schafer <cody@linux.vnet.ibm.com>
 * Copyright 2014 IBM Corporation.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */


#define pr_fmt(fmt) "hv-24x7: " fmt

#include <linux/perf_event.h>
#include <linux/rbtree.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>

#include <asm/cputhreads.h>
#include <asm/firmware.h>
#include <asm/hvcall.h>
#include <asm/io.h>
#include <linux/byteorder/generic.h>

#include "hv-24x7.h"
#include "hv-24x7-catalog.h"
#include "hv-common.h"

/* Version of the 24x7 hypervisor API that we should use in this machine. */

static int interface_version;

/* Whether we have to aggregate result data for some domains. */

static bool aggregate_result_elements;



static bool domain_is_valid(unsigned domain)
{
	switch (domain) {

#define DOMAIN(n, v, x, c)		\
	case HV_PERF_DOMAIN_##n:	\
		/* fall through */
#include "hv-24x7-domains.h"

#undef DOMAIN
		return true;
	default:
		return false;
	}
}

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static bool is_physical_domain(unsigned domain)
{
	switch (domain) {

#define DOMAIN(n, v, x, c)		\
	case HV_PERF_DOMAIN_##n:        \
                return c;
#include "hv-24x7-domains.h"

#undef DOMAIN
	default:
		return false;
	}
}

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/* Domains for which more than one result element are returned for each event. */


static bool domain_needs_aggregation(unsigned int domain)
{
	return aggregate_result_elements &&
			(domain == HV_PERF_DOMAIN_PHYS_CORE ||
			 (domain >= HV_PERF_DOMAIN_VCPU_HOME_CORE &&
			  domain <= HV_PERF_DOMAIN_VCPU_REMOTE_NODE));
}

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static const char *domain_name(unsigned domain)
{
	if (!domain_is_valid(domain))
		return NULL;

	switch (domain) {
	case HV_PERF_DOMAIN_PHYS_CHIP:		return "Physical Chip";
	case HV_PERF_DOMAIN_PHYS_CORE:		return "Physical Core";
	case HV_PERF_DOMAIN_VCPU_HOME_CORE:	return "VCPU Home Core";
	case HV_PERF_DOMAIN_VCPU_HOME_CHIP:	return "VCPU Home Chip";
	case HV_PERF_DOMAIN_VCPU_HOME_NODE:	return "VCPU Home Node";
	case HV_PERF_DOMAIN_VCPU_REMOTE_NODE:	return "VCPU Remote Node";
	}

	WARN_ON_ONCE(domain);
	return NULL;
}

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static bool catalog_entry_domain_is_valid(unsigned domain)
{
	/* POWER8 doesn't support virtual domains. */
	if (interface_version == 1)
		return is_physical_domain(domain);
	else
		return domain_is_valid(domain);
}

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/*
 * TODO: Merging events:
 * - Think of the hcall as an interface to a 4d array of counters:
 *   - x = domains
 *   - y = indexes in the domain (core, chip, vcpu, node, etc)
 *   - z = offset into the counter space
 *   - w = lpars (guest vms, "logical partitions")
 * - A single request is: x,y,y_last,z,z_last,w,w_last
 *   - this means we can retrieve a rectangle of counters in y,z for a single x.
 *
 * - Things to consider (ignoring w):
 *   - input  cost_per_request = 16
 *   - output cost_per_result(ys,zs)  = 8 + 8 * ys + ys * zs
 *   - limited number of requests per hcall (must fit into 4K bytes)
 *     - 4k = 16 [buffer header] - 16 [request size] * request_count
 *     - 255 requests per hcall
 *   - sometimes it will be more efficient to read extra data and discard
 */

/*
 * Example usage:
 *  perf stat -e 'hv_24x7/domain=2,offset=8,vcpu=0,lpar=0xffffffff/'
 */

/* u3 0-6, one of HV_24X7_PERF_DOMAIN */
EVENT_DEFINE_RANGE_FORMAT(domain, config, 0, 3);
/* u16 */
EVENT_DEFINE_RANGE_FORMAT(core, config, 16, 31);
EVENT_DEFINE_RANGE_FORMAT(chip, config, 16, 31);
EVENT_DEFINE_RANGE_FORMAT(vcpu, config, 16, 31);
/* u32, see "data_offset" */
EVENT_DEFINE_RANGE_FORMAT(offset, config, 32, 63);
/* u16 */
EVENT_DEFINE_RANGE_FORMAT(lpar, config1, 0, 15);

EVENT_DEFINE_RANGE(reserved1, config,   4, 15);
EVENT_DEFINE_RANGE(reserved2, config1, 16, 63);
EVENT_DEFINE_RANGE(reserved3, config2,  0, 63);


static struct attribute *format_attrs[] = {
	&format_attr_domain.attr,
	&format_attr_offset.attr,
	&format_attr_core.attr,
	&format_attr_chip.attr,
	&format_attr_vcpu.attr,
	&format_attr_lpar.attr,
	NULL,
};


static struct attribute_group format_group = {
	.name = "format",
	.attrs = format_attrs,
};


static struct attribute_group event_group = {
	.name = "events",
	/* .attrs is set in init */
};


static struct attribute_group event_desc_group = {
	.name = "event_descs",
	/* .attrs is set in init */
};


static struct attribute_group event_long_desc_group = {
	.name = "event_long_descs",
	/* .attrs is set in init */
};


static struct kmem_cache *hv_page_cache;

DEFINE_PER_CPU(int, hv_24x7_txn_flags);
DEFINE_PER_CPU(int, hv_24x7_txn_err);


struct hv_24x7_hw {
	
struct perf_event *events[255];
};

DEFINE_PER_CPU(struct hv_24x7_hw, hv_24x7_hw);

/*
 * request_buffer and result_buffer are not required to be 4k aligned,
 * but are not allowed to cross any 4k boundary. Aligning them to 4k is
 * the simplest way to ensure that.
 */

#define H24x7_DATA_BUFFER_SIZE	4096
DEFINE_PER_CPU(char, hv_24x7_reqb[H24x7_DATA_BUFFER_SIZE]) __aligned(4096);
DEFINE_PER_CPU(char, hv_24x7_resb[H24x7_DATA_BUFFER_SIZE]) __aligned(4096);



static unsigned int max_num_requests(int interface_version)
{
	return (H24x7_DATA_BUFFER_SIZE - sizeof(struct hv_24x7_request_buffer))
		/ H24x7_REQUEST_SIZE(interface_version);
}

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static char *event_name(struct hv_24x7_event_data *ev, int *len)
{
	*len = be16_to_cpu(ev->event_name_len) - 2;
	return (char *)ev->remainder;
}

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static char *event_desc(struct hv_24x7_event_data *ev, int *len)
{
	unsigned nl = be16_to_cpu(ev->event_name_len);
	__be16 *desc_len = (__be16 *)(ev->remainder + nl - 2);

	*len = be16_to_cpu(*desc_len) - 2;
	return (char *)ev->remainder + nl;
}

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static char *event_long_desc(struct hv_24x7_event_data *ev, int *len)
{
	unsigned nl = be16_to_cpu(ev->event_name_len);
	__be16 *desc_len_ = (__be16 *)(ev->remainder + nl - 2);
	unsigned desc_len = be16_to_cpu(*desc_len_);
	__be16 *long_desc_len = (__be16 *)(ev->remainder + nl + desc_len - 2);

	*len = be16_to_cpu(*long_desc_len) - 2;
	return (char *)ev->remainder + nl + desc_len;
}

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static bool event_fixed_portion_is_within(struct hv_24x7_event_data *ev,
					  void *end)
{
	void *start = ev;

	return (start + offsetof(struct hv_24x7_event_data, remainder)) < end;
}

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/*
 * Things we don't check:
 *  - padding for desc, name, and long/detailed desc is required to be '\0'
 *    bytes.
 *
 *  Return NULL if we pass end,
 *  Otherwise return the address of the byte just following the event.
 */


static void *event_end(struct hv_24x7_event_data *ev, void *end)
{
	void *start = ev;
	__be16 *dl_, *ldl_;
	unsigned dl, ldl;
	unsigned nl = be16_to_cpu(ev->event_name_len);

	if (nl < 2) {
		pr_debug("%s: name length too short: %d", __func__, nl);
		return NULL;
	}

	if (start + nl > end) {
		pr_debug("%s: start=%p + nl=%u > end=%p",
				__func__, start, nl, end);
		return NULL;
	}

	dl_ = (__be16 *)(ev->remainder + nl - 2);
	if (!IS_ALIGNED((uintptr_t)dl_, 2))
		pr_warn("desc len not aligned %p", dl_);
	dl = be16_to_cpu(*dl_);
	if (dl < 2) {
		pr_debug("%s: desc len too short: %d", __func__, dl);
		return NULL;
	}

	if (start + nl + dl > end) {
		pr_debug("%s: (start=%p + nl=%u + dl=%u)=%p > end=%p",
				__func__, start, nl, dl, start + nl + dl, end);
		return NULL;
	}

	ldl_ = (__be16 *)(ev->remainder + nl + dl - 2);
	if (!IS_ALIGNED((uintptr_t)ldl_, 2))
		pr_warn("long desc len not aligned %p", ldl_);
	ldl = be16_to_cpu(*ldl_);
	if (ldl < 2) {
		pr_debug("%s: long desc len too short (ldl=%u)",
				__func__, ldl);
		return NULL;
	}

	if (start + nl + dl + ldl > end) {
		pr_debug("%s: start=%p + nl=%u + dl=%u + ldl=%u > end=%p",
				__func__, start, nl, dl, ldl, end);
		return NULL;
	}

	return start + nl + dl + ldl;
}

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static long h_get_24x7_catalog_page_(unsigned long phys_4096,
				     unsigned long version, unsigned long index)
{
	pr_devel("h_get_24x7_catalog_page(0x%lx, %lu, %lu)",
			phys_4096, version, index);

	WARN_ON(!IS_ALIGNED(phys_4096, 4096));

	return plpar_hcall_norets(H_GET_24X7_CATALOG_PAGE,
			phys_4096, version, index);
}

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static long h_get_24x7_catalog_page(char page[], u64 version, u32 index)
{
	return h_get_24x7_catalog_page_(virt_to_phys(page),
					version, index);
}

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/*
 * Each event we find in the catalog, will have a sysfs entry. Format the
 * data for this sysfs entry based on the event's domain.
 *
 * Events belonging to the Chip domain can only be monitored in that domain.
 * i.e the domain for these events is a fixed/knwon value.
 *
 * Events belonging to the Core domain can be monitored either in the physical
 * core or in one of the virtual CPU domains. So the domain value for these
 * events must be specified by the user (i.e is a required parameter). Format
 * the Core events with 'domain=?' so the perf-tool can error check required
 * parameters.
 *
 * NOTE: For the Core domain events, rather than making domain a required
 *       parameter we could default it to PHYS_CORE and allowe users to
 *       override the domain to one of the VCPU domains.
 *
 *       However, this can make the interface a little inconsistent.
 *
 *       If we set domain=2 (PHYS_CHIP) and allow user to override this field
 *       the user may be tempted to also modify the "offset=x" field in which
 *       can lead to confusing usage. Consider the HPM_PCYC (offset=0x18) and
 *       HPM_INST (offset=0x20) events. With:
 *
 *              perf stat -e hv_24x7/HPM_PCYC,offset=0x20/
 *
 *      we end up monitoring HPM_INST, while the command line has HPM_PCYC.
 *
 *      By not assigning a default value to the domain for the Core events,
 *      we can have simple guidelines:
 *
 *              - Specifying values for parameters with "=?" is required.
 *
 *              - Specifying (i.e overriding) values for other parameters
 *                is undefined.
 */


static char *event_fmt(struct hv_24x7_event_data *event, unsigned domain)
{
	const char *sindex;
	const char *lpar;
	const char *domain_str;
	char buf[8];

	switch (domain) {
	case HV_PERF_DOMAIN_PHYS_CHIP:
		snprintf(buf, sizeof(buf), "%d", domain);
		domain_str = buf;
		lpar = "0x0";
		sindex = "chip";
		break;
	case HV_PERF_DOMAIN_PHYS_CORE:
		domain_str = "?";
		lpar = "0x0";
		sindex = "core";
		break;
	default:
		domain_str = "?";
		lpar = "?";
		sindex = "vcpu";
	}

	return kasprintf(GFP_KERNEL,
			"domain=%s,offset=0x%x,%s=?,lpar=%s",
			domain_str,
			be16_to_cpu(event->event_counter_offs) +
				be16_to_cpu(event->event_group_record_offs),
			sindex,
			lpar);
}

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/* Avoid trusting fw to NUL terminate strings */


static char *memdup_to_str(char *maybe_str, int max_len, gfp_t gfp)
{
	return kasprintf(gfp, "%.*s", max_len, maybe_str);
}

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static ssize_t device_show_string(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct dev_ext_attribute *d;

	d = container_of(attr, struct dev_ext_attribute, attr);

	return sprintf(buf, "%s\n", (char *)d->var);
}

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static struct attribute *device_str_attr_create_(char *name, char *str)
{
	struct dev_ext_attribute *attr = kzalloc(sizeof(*attr), GFP_KERNEL);

	if (!attr)
		return NULL;

	sysfs_attr_init(&attr->attr.attr);

	attr->var = str;
	attr->attr.attr.name = name;
	attr->attr.attr.mode = 0444;
	attr->attr.show = device_show_string;

	return &attr->attr.attr;
}

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/*
 * Allocate and initialize strings representing event attributes.
 *
 * NOTE: The strings allocated here are never destroyed and continue to
 *       exist till shutdown. This is to allow us to create as many events
 *       from the catalog as possible, even if we encounter errors with some.
 *       In case of changes to error paths in future, these may need to be
 *       freed by the caller.
 */


static struct attribute *device_str_attr_create(char *name, int name_max,
						int name_nonce,
						char *str, size_t str_max)
{
	char *n;
	char *s = memdup_to_str(str, str_max, GFP_KERNEL);
	struct attribute *a;

	if (!s)
		return NULL;

	if (!name_nonce)
		n = kasprintf(GFP_KERNEL, "%.*s", name_max, name);
	else
		n = kasprintf(GFP_KERNEL, "%.*s__%d", name_max, name,
					name_nonce);
	if (!n)
		goto out_s;

	a = device_str_attr_create_(n, s);
	if (!a)
		goto out_n;

	return a;
out_n:
	kfree(n);
out_s:
	kfree(s);
	return NULL;
}

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static struct attribute *event_to_attr(unsigned ix,
				       struct hv_24x7_event_data *event,
				       unsigned domain,
				       int nonce)
{
	int event_name_len;
	char *ev_name, *a_ev_name, *val;
	struct attribute *attr;

	if (!domain_is_valid(domain)) {
		pr_warn("catalog event %u has invalid domain %u\n",
				ix, domain);
		return NULL;
	}

	val = event_fmt(event, domain);
	if (!val)
		return NULL;

	ev_name = event_name(event, &event_name_len);
	if (!nonce)
		a_ev_name = kasprintf(GFP_KERNEL, "%.*s",
				(int)event_name_len, ev_name);
	else
		a_ev_name = kasprintf(GFP_KERNEL, "%.*s__%d",
				(int)event_name_len, ev_name, nonce);

	if (!a_ev_name)
		goto out_val;

	attr = device_str_attr_create_(a_ev_name, val);
	if (!attr)
		goto out_name;

	return attr;
out_name:
	kfree(a_ev_name);
out_val:
	kfree(val);
	return NULL;
}

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static struct attribute *event_to_desc_attr(struct hv_24x7_event_data *event,
					    int nonce)
{
	int nl, dl;
	char *name = event_name(event, &nl);
	char *desc = event_desc(event, &dl);

	/* If there isn't a description, don't create the sysfs file */
	if (!dl)
		return NULL;

	return device_str_attr_create(name, nl, nonce, desc, dl);
}

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static struct attribute *

event_to_long_desc_attr(struct hv_24x7_event_data *event, int nonce)
{
	int nl, dl;
	char *name = event_name(event, &nl);
	char *desc = event_long_desc(event, &dl);

	/* If there isn't a description, don't create the sysfs file */
	if (!dl)
		return NULL;

	return device_str_attr_create(name, nl, nonce, desc, dl);
}

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static int event_data_to_attrs(unsigned ix, struct attribute **attrs,
				   struct hv_24x7_event_data *event, int nonce)
{
	*attrs = event_to_attr(ix, event, event->domain, nonce);
	if (!*attrs)
		return -1;

	return 0;
}

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/* */

struct event_uniq {
	
struct rb_node node;
	
const char *name;
	
int nl;
	
unsigned ct;
	
unsigned domain;
};



static int memord(const void *d1, size_t s1, const void *d2, size_t s2)
{
	if (s1 < s2)
		return 1;
	if (s2 > s1)
		return -1;

	return memcmp(d1, d2, s1);
}

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static int ev_uniq_ord(const void *v1, size_t s1, unsigned d1, const void *v2,
		       size_t s2, unsigned d2)
{
	int r = memord(v1, s1, v2, s2);

	if (r)
		return r;
	if (d1 > d2)
		return 1;
	if (d2 > d1)
		return -1;
	return 0;
}

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static int event_uniq_add(struct rb_root *root, const char *name, int nl,
			  unsigned domain)
{
	struct rb_node **new = &(root->rb_node), *parent = NULL;
	struct event_uniq *data;

	/* Figure out where to put new node */
	while (*new) {
		struct event_uniq *it;
		int result;

		it = container_of(*new, struct event_uniq, node);
		result = ev_uniq_ord(name, nl, domain, it->name, it->nl,
					it->domain);

		parent = *new;
		if (result < 0)
			new = &((*new)->rb_left);
		else if (result > 0)
			new = &((*new)->rb_right);
		else {
			it->ct++;
			pr_info("found a duplicate event %.*s, ct=%u\n", nl,
						name, it->ct);
			return it->ct;
		}
	}

	data = kmalloc(sizeof(*data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	*data = (struct event_uniq) {
		.name = name,
		.nl = nl,
		.ct = 0,
		.domain = domain,
        };

	/* Add new node and rebalance tree. */
	rb_link_node(&data->node, parent, new);
	rb_insert_color(&data->node, root);

	/* data->ct */
	return 0;
}

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static void event_uniq_destroy(struct rb_root *root)
{
	/*
         * the strings we point to are in the giant block of memory filled by
         * the catalog, and are freed separately.
         */
	struct event_uniq *pos, *n;

	rbtree_postorder_for_each_entry_safe(pos, n, root, node)
		kfree(pos);
}


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/*
 * ensure the event structure's sizes are self consistent and don't cause us to
 * read outside of the event
 *
 * On success, return the event length in bytes.
 * Otherwise, return -1 (and print as appropriate).
 */


static ssize_t catalog_event_len_validate(struct hv_24x7_event_data *event,
					  size_t event_idx,
					  size_t event_data_bytes,
					  size_t event_entry_count,
					  size_t offset, void *end)
{
	ssize_t ev_len;
	void *ev_end, *calc_ev_end;

	if (offset >= event_data_bytes)
		return -1;

	if (event_idx >= event_entry_count) {
		pr_devel("catalog event data has %zu bytes of padding after last event\n",
				event_data_bytes - offset);
		return -1;
	}

	if (!event_fixed_portion_is_within(event, end)) {
		pr_warn("event %zu fixed portion is not within range\n",
				event_idx);
		return -1;
	}

	ev_len = be16_to_cpu(event->length);

	if (ev_len % 16)
		pr_info("event %zu has length %zu not divisible by 16: event=%pK\n",
				event_idx, ev_len, event);

	ev_end = (__u8 *)event + ev_len;
	if (ev_end > end) {
		pr_warn("event %zu has .length=%zu, ends after buffer end: ev_end=%pK > end=%pK, offset=%zu\n",
				event_idx, ev_len, ev_end, end,
				offset);
		return -1;
	}

	calc_ev_end = event_end(event, end);
	if (!calc_ev_end) {
		pr_warn("event %zu has a calculated length which exceeds buffer length %zu: event=%pK end=%pK, offset=%zu\n",
			event_idx, event_data_bytes, event, end,
			offset);
		return -1;
	}

	if (calc_ev_end > ev_end) {
		pr_warn("event %zu exceeds it's own length: event=%pK, end=%pK, offset=%zu, calc_ev_end=%pK\n",
			event_idx, event, ev_end, offset, calc_ev_end);
		return -1;
	}

	return ev_len;
}

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#define MAX_4K (SIZE_MAX / 4096)



static int create_events_from_catalog(struct attribute ***events_,
				      struct attribute ***event_descs_,
				      struct attribute ***event_long_descs_)
{
	long hret;
	size_t catalog_len, catalog_page_len, event_entry_count,
	       event_data_len, event_data_offs,
	       event_data_bytes, junk_events, event_idx, event_attr_ct, i,
	       attr_max, event_idx_last, desc_ct, long_desc_ct;
	ssize_t ct, ev_len;
	uint64_t catalog_version_num;
	struct attribute **events, **event_descs, **event_long_descs;
	struct hv_24x7_catalog_page_0 *page_0 =
		kmem_cache_alloc(hv_page_cache, GFP_KERNEL);
	void *page = page_0;
	void *event_data, *end;
	struct hv_24x7_event_data *event;
	struct rb_root ev_uniq = RB_ROOT;
	int ret = 0;

	if (!page) {
		ret = -ENOMEM;
		goto e_out;
	}

	hret = h_get_24x7_catalog_page(page, 0, 0);
	if (hret) {
		ret = -EIO;
		goto e_free;
	}

	catalog_version_num = be64_to_cpu(page_0->version);
	catalog_page_len = be32_to_cpu(page_0->length);

	if (MAX_4K < catalog_page_len) {
		pr_err("invalid page count: %zu\n", catalog_page_len);
		ret