[linux-2.6-block.git] / arch / x86 / kernel / cpu / mcheck / mce-genpool.c

/*
 * MCE event pool management in MCE context
 *
 * Copyright (C) 2015 Intel Corp.
 * Author: Chen, Gong <gong.chen@linux.intel.com>
 *
 * This file is licensed under GPLv2.
 */
#include <linux/smp.h>
#include <linux/mm.h>
#include <linux/genalloc.h>
#include <linux/llist.h>
#include "mce-internal.h"

/*
 * printk() is not safe in MCE context. This is a lock-less memory allocator
 * used to save error information organized in a lock-less list.
 *
 * This memory pool is only to be used to save MCE records in MCE context.
 * MCE events are rare, so a fixed size memory pool should be enough. Use
 * 2 pages to save MCE events for now (~80 MCE records at most).
 */
#define MCE_POOLSZ	(2 * PAGE_SIZE)

static struct gen_pool *mce_evt_pool;
static LLIST_HEAD(mce_event_llist);
static char gen_pool_buf[MCE_POOLSZ];

/*
 * Compare the record "t" with each of the records on list "l" to see if
 * an equivalent one is present in the list.
 */
static bool is_duplicate_mce_record(struct mce_evt_llist *t, struct mce_evt_llist *l)
{
	struct mce_evt_llist *node;
	struct mce *m1, *m2;

	m1 = &t->mce;

	llist_for_each_entry(node, &l->llnode, llnode) {
		m2 = &node->mce;

		if (!mce_cmp(m1, m2))
			return true;
	}
	return false;
}

/*
 * The system has panicked - we'd like to peruse the list of MCE records
 * that have been queued, but not seen by anyone yet.  The list is in
 * reverse time order, so we need to reverse it. While doing that we can
 * also drop duplicate records (these were logged because some banks are
 * shared between cores or by all threads on a socket).
 */
struct llist_node *mce_gen_pool_prepare_records(void)
{
	struct llist_node *head;
	LLIST_HEAD(new_head);
	struct mce_evt_llist *node, *t;

	head = llist_del_all(&mce_event_llist);
	if (!head)
		return NULL;

	/* squeeze out duplicates while reversing order */
	llist_for_each_entry_safe(node, t, head, llnode) {
		if (!is_duplicate_mce_record(node, t))
			llist_add(&node->llnode, &new_head);
	}

	return new_head.first;
}

void mce_gen_pool_process(void)
{
	struct llist_node *head;
	struct mce_evt_llist *node, *tmp;
	struct mce *mce;

	head = llist_del_all(&mce_event_llist);
	if (!head)
		return;

	head = llist_reverse_order(head);
	llist_for_each_entry_safe(node, tmp, head, llnode) {
		mce = &node->mce;
		atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, mce);
		gen_pool_free(mce_evt_pool, (unsigned long)node, sizeof(*node));
	}
}

bool mce_gen_pool_empty(void)
{
	return llist_empty(&mce_event_llist);
}

int mce_gen_pool_add(struct mce *mce)
{
	struct mce_evt_llist *node;

	if (!mce_evt_pool)
		return -EINVAL;

	node = (void *)gen_pool_alloc(mce_evt_pool, sizeof(*node));
	if (!node) {
		pr_warn_ratelimited("MCE records pool full!\n");
		return -ENOMEM;
	}

	memcpy(&node->mce, mce, sizeof(*mce));
	llist_add(&node->llnode, &mce_event_llist);

	return 0;
}

static int mce_gen_pool_create(void)
{
	struct gen_pool *tmpp;
	int ret = -ENOMEM;

	tmpp = gen_pool_create(ilog2(sizeof(struct mce_evt_llist)), -1);
	if (!tmpp)
		goto out;

	ret = gen_pool_add(tmpp, (unsigned long)gen_pool_buf, MCE_POOLSZ, -1);
	if (ret) {
		gen_pool_destroy(tmpp);
		goto out;
	}

	mce_evt_pool = tmpp;

out:
	return ret;
}

int mce_gen_pool_init(void)
{
	/* Just init mce_gen_pool once. */
	if (mce_evt_pool)
		return 0;

	return mce_gen_pool_create();
}
Commit	Line	Data
648ed940 CG	1	/*
	2	* MCE event pool management in MCE context
	3	*
	4	* Copyright (C) 2015 Intel Corp.
	5	* Author: Chen, Gong <gong.chen@linux.intel.com>
	6	*
	7	* This file is licensed under GPLv2.
	8	*/
	9	#include <linux/smp.h>
	10	#include <linux/mm.h>
	11	#include <linux/genalloc.h>
	12	#include <linux/llist.h>
	13	#include "mce-internal.h"
	14
	15	/*
	16	* printk() is not safe in MCE context. This is a lock-less memory allocator
	17	* used to save error information organized in a lock-less list.
	18	*
	19	* This memory pool is only to be used to save MCE records in MCE context.
	20	* MCE events are rare, so a fixed size memory pool should be enough. Use
	21	* 2 pages to save MCE events for now (~80 MCE records at most).
	22	*/
	23	#define MCE_POOLSZ (2 * PAGE_SIZE)
	24
	25	static struct gen_pool *mce_evt_pool;
	26	static LLIST_HEAD(mce_event_llist);
	27	static char gen_pool_buf[MCE_POOLSZ];
	28
5541c93c TL	29	/*
	30	* Compare the record "t" with each of the records on list "l" to see if
	31	* an equivalent one is present in the list.
	32	*/
	33	static bool is_duplicate_mce_record(struct mce_evt_llist t, struct mce_evt_llist l)
	34	{
	35	struct mce_evt_llist *node;
	36	struct mce m1, m2;
	37
	38	m1 = &t->mce;
	39
	40	llist_for_each_entry(node, &l->llnode, llnode) {
	41	m2 = &node->mce;
	42
	43	if (!mce_cmp(m1, m2))
	44	return true;
	45	}
	46	return false;
	47	}
	48
	49	/*
	50	* The system has panicked - we'd like to peruse the list of MCE records
	51	* that have been queued, but not seen by anyone yet. The list is in
	52	* reverse time order, so we need to reverse it. While doing that we can
	53	* also drop duplicate records (these were logged because some banks are
	54	* shared between cores or by all threads on a socket).
	55	*/
	56	struct llist_node *mce_gen_pool_prepare_records(void)
	57	{
	58	struct llist_node *head;
	59	LLIST_HEAD(new_head);
	60	struct mce_evt_llist node, t;
	61
	62	head = llist_del_all(&mce_event_llist);
	63	if (!head)
	64	return NULL;
	65
	66	/* squeeze out duplicates while reversing order */
	67	llist_for_each_entry_safe(node, t, head, llnode) {
	68	if (!is_duplicate_mce_record(node, t))
	69	llist_add(&node->llnode, &new_head);
	70	}
	71
	72	return new_head.first;
	73	}
	74
648ed940 CG	75	void mce_gen_pool_process(void)
	76	{
	77	struct llist_node *head;
a3125494	78	struct mce_evt_llist node, tmp;
648ed940 CG	79	struct mce *mce;
	80
	81	head = llist_del_all(&mce_event_llist);
	82	if (!head)
	83	return;
	84
	85	head = llist_reverse_order(head);
a3125494	86	llist_for_each_entry_safe(node, tmp, head, llnode) {
648ed940 CG	87	mce = &node->mce;
	88	atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, mce);
	89	gen_pool_free(mce_evt_pool, (unsigned long)node, sizeof(*node));
	90	}
	91	}
	92
	93	bool mce_gen_pool_empty(void)
	94	{
	95	return llist_empty(&mce_event_llist);
	96	}
	97
	98	int mce_gen_pool_add(struct mce *mce)
	99	{
	100	struct mce_evt_llist *node;
	101
	102	if (!mce_evt_pool)
	103	return -EINVAL;
	104
	105	node = (void )gen_pool_alloc(mce_evt_pool, sizeof(node));
	106	if (!node) {
	107	pr_warn_ratelimited("MCE records pool full!\n");
	108	return -ENOMEM;
	109	}
	110
	111	memcpy(&node->mce, mce, sizeof(*mce));
	112	llist_add(&node->llnode, &mce_event_llist);
	113
	114	return 0;
	115	}
	116
	117	static int mce_gen_pool_create(void)
	118	{
	119	struct gen_pool *tmpp;
	120	int ret = -ENOMEM;
	121
	122	tmpp = gen_pool_create(ilog2(sizeof(struct mce_evt_llist)), -1);
	123	if (!tmpp)
	124	goto out;
	125
	126	ret = gen_pool_add(tmpp, (unsigned long)gen_pool_buf, MCE_POOLSZ, -1);
	127	if (ret) {
	128	gen_pool_destroy(tmpp);
	129	goto out;
	130	}
	131
	132	mce_evt_pool = tmpp;
	133
	134	out:
	135	return ret;
	136	}
	137
	138	int mce_gen_pool_init(void)
	139	{
	140	/* Just init mce_gen_pool once. */
	141	if (mce_evt_pool)
	142	return 0;
	143
	144	return mce_gen_pool_create();
	145	}