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/*
* 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];
void mce_gen_pool_process(void)
{
struct llist_node *head;
struct mce_evt_llist *node;
struct mce *mce;
head = llist_del_all(&mce_event_llist);
if (!head)
return;
head = llist_reverse_order(head);
llist_for_each_entry(node, 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();
}
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