146 lines
3.3 KiB
C
146 lines
3.3 KiB
C
/*
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* MCE event pool management in MCE context
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*
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* Copyright (C) 2015 Intel Corp.
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* Author: Chen, Gong <gong.chen@linux.intel.com>
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*
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* This file is licensed under GPLv2.
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*/
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#include <linux/smp.h>
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#include <linux/mm.h>
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#include <linux/genalloc.h>
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#include <linux/llist.h>
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#include "mce-internal.h"
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/*
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* printk() is not safe in MCE context. This is a lock-less memory allocator
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* used to save error information organized in a lock-less list.
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*
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* This memory pool is only to be used to save MCE records in MCE context.
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* MCE events are rare, so a fixed size memory pool should be enough. Use
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* 2 pages to save MCE events for now (~80 MCE records at most).
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*/
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#define MCE_POOLSZ (2 * PAGE_SIZE)
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static struct gen_pool *mce_evt_pool;
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static LLIST_HEAD(mce_event_llist);
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static char gen_pool_buf[MCE_POOLSZ];
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/*
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* Compare the record "t" with each of the records on list "l" to see if
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* an equivalent one is present in the list.
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*/
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static bool is_duplicate_mce_record(struct mce_evt_llist *t, struct mce_evt_llist *l)
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{
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struct mce_evt_llist *node;
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struct mce *m1, *m2;
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m1 = &t->mce;
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llist_for_each_entry(node, &l->llnode, llnode) {
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m2 = &node->mce;
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if (!mce_cmp(m1, m2))
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return true;
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}
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return false;
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}
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/*
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* The system has panicked - we'd like to peruse the list of MCE records
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* that have been queued, but not seen by anyone yet. The list is in
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* reverse time order, so we need to reverse it. While doing that we can
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* also drop duplicate records (these were logged because some banks are
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* shared between cores or by all threads on a socket).
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*/
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struct llist_node *mce_gen_pool_prepare_records(void)
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{
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struct llist_node *head;
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LLIST_HEAD(new_head);
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struct mce_evt_llist *node, *t;
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head = llist_del_all(&mce_event_llist);
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if (!head)
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return NULL;
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/* squeeze out duplicates while reversing order */
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llist_for_each_entry_safe(node, t, head, llnode) {
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if (!is_duplicate_mce_record(node, t))
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llist_add(&node->llnode, &new_head);
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}
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return new_head.first;
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}
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void mce_gen_pool_process(struct work_struct *__unused)
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{
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struct llist_node *head;
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struct mce_evt_llist *node, *tmp;
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struct mce *mce;
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head = llist_del_all(&mce_event_llist);
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if (!head)
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return;
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head = llist_reverse_order(head);
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llist_for_each_entry_safe(node, tmp, head, llnode) {
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mce = &node->mce;
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blocking_notifier_call_chain(&x86_mce_decoder_chain, 0, mce);
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gen_pool_free(mce_evt_pool, (unsigned long)node, sizeof(*node));
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}
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}
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bool mce_gen_pool_empty(void)
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{
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return llist_empty(&mce_event_llist);
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}
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int mce_gen_pool_add(struct mce *mce)
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{
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struct mce_evt_llist *node;
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if (!mce_evt_pool)
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return -EINVAL;
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node = (void *)gen_pool_alloc(mce_evt_pool, sizeof(*node));
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if (!node) {
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pr_warn_ratelimited("MCE records pool full!\n");
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return -ENOMEM;
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}
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memcpy(&node->mce, mce, sizeof(*mce));
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llist_add(&node->llnode, &mce_event_llist);
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return 0;
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}
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static int mce_gen_pool_create(void)
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{
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struct gen_pool *tmpp;
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int ret = -ENOMEM;
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tmpp = gen_pool_create(ilog2(sizeof(struct mce_evt_llist)), -1);
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if (!tmpp)
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goto out;
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ret = gen_pool_add(tmpp, (unsigned long)gen_pool_buf, MCE_POOLSZ, -1);
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if (ret) {
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gen_pool_destroy(tmpp);
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goto out;
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}
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mce_evt_pool = tmpp;
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out:
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return ret;
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}
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int mce_gen_pool_init(void)
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{
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/* Just init mce_gen_pool once. */
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if (mce_evt_pool)
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return 0;
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return mce_gen_pool_create();
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}
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