x86/mce: Provide a lockless memory pool to save error records (648ed940) · Commits · 戴 / test

arch/x86/Kconfig

+1 −0

Original line number	Diff line number	Diff line
		@@ -955,6 +955,7 @@ config X86_REROUTE_FOR_BROKEN_BOOT_IRQS

		config X86_MCE
		bool "Machine Check / overheating reporting"
		select GENERIC_ALLOCATOR
		default y
		---help---
		Machine Check support allows the processor to notify the

arch/x86/kernel/cpu/mcheck/Makefile

+1 −1

Original line number	Diff line number	Diff line
		obj-y = mce.o mce-severity.o
		obj-y = mce.o mce-severity.o mce-genpool.o

		obj-$(CONFIG_X86_ANCIENT_MCE) += winchip.o p5.o
		obj-$(CONFIG_X86_MCE_INTEL) += mce_intel.o

arch/x86/kernel/cpu/mcheck/mce-genpool.c

0 → 100644

+99 −0

Original line number	Diff line number	Diff line
		/*
		* 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();
		}

arch/x86/kernel/cpu/mcheck/mce-internal.h

+12 −0

Original line number	Diff line number	Diff line
		@@ -13,6 +13,8 @@ enum severity_level {
		MCE_PANIC_SEVERITY,
		};

		extern struct atomic_notifier_head x86_mce_decoder_chain;

		#define ATTR_LEN 16
		#define INITIAL_CHECK_INTERVAL 5 * 60 /* 5 minutes */

		@@ -24,6 +26,16 @@ struct mce_bank {
		char attrname[ATTR_LEN]; /* attribute name */
		};

		struct mce_evt_llist {
		struct llist_node llnode;
		struct mce mce;
		};

		void mce_gen_pool_process(void);
		bool mce_gen_pool_empty(void);
		int mce_gen_pool_add(struct mce *mce);
		int mce_gen_pool_init(void);

		extern int (mce_severity)(struct mce a, int tolerant, char **msg, bool is_excp);
		struct dentry *mce_get_debugfs_dir(void);

arch/x86/kernel/cpu/mcheck/mce.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -118,7 +118,7 @@ static void (quirk_no_way_out)(int bank, struct mce m, struct pt_regs *regs);
		* CPU/chipset specific EDAC code can register a notifier call here to print
		* MCE errors in a human-readable form.
		*/
		static ATOMIC_NOTIFIER_HEAD(x86_mce_decoder_chain);
		ATOMIC_NOTIFIER_HEAD(x86_mce_decoder_chain);

		/* Do initial initialization of a struct mce */
		void mce_setup(struct mce *m)
		@@ -1731,6 +1731,12 @@ void mcheck_cpu_init(struct cpuinfo_x86 *c)
		return;
		}

		if (mce_gen_pool_init()) {
		mca_cfg.disabled = true;
		pr_emerg("Couldn't allocate MCE records pool!\n");
		return;
		}

		machine_check_vector = do_machine_check;

		__mcheck_cpu_init_generic();

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