[PATCH 3/3] ia64: Call migration code on correctable errors v6

[Russ Anderson]

Migrate data off pages with correctable memory errors.  This patch is the 
ia64 specific piece.  It connects the CPE handler to the page migration
code.  It is implemented as a kernel loadable module, similar to the mca
recovery code (mca_recovery.ko).  This allows the feature to be turned off
by uninstalling the module.  


Signed-off-by: Russ Anderson <rja@xxxxxxx>

---
 arch/ia64/Kconfig              |    9 
 arch/ia64/kernel/Makefile      |    1 
 arch/ia64/kernel/cpe_migrate.c |  419 +++++++++++++++++++++++++++++++++++++++++
 arch/ia64/kernel/mca.c         |   37 +++
 include/asm-ia64/mca.h         |    6 
 include/asm-ia64/page.h        |    1 
 mm/migrate.c                   |    4 
 7 files changed, 476 insertions(+), 1 deletion(-)

Index: linux-next/arch/ia64/kernel/Makefile
===================================================================
--- linux-next.orig/arch/ia64/kernel/Makefile	2008-06-09 09:26:44.750649655 -0500
+++ linux-next/arch/ia64/kernel/Makefile	2008-06-09 09:26:56.964171339 -0500
@@ -27,6 +27,7 @@ obj-$(CONFIG_PERFMON)		+= perfmon_defaul
 obj-$(CONFIG_IA64_CYCLONE)	+= cyclone.o
 obj-$(CONFIG_CPU_FREQ)		+= cpufreq/
 obj-$(CONFIG_IA64_MCA_RECOVERY)	+= mca_recovery.o
+obj-$(CONFIG_IA64_CPE_MIGRATE)	+= cpe_migrate.o
 obj-$(CONFIG_KPROBES)		+= kprobes.o jprobes.o
 obj-$(CONFIG_KEXEC)		+= machine_kexec.o relocate_kernel.o crash.o
 obj-$(CONFIG_CRASH_DUMP)	+= crash_dump.o
Index: linux-next/arch/ia64/kernel/cpe_migrate.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-next/arch/ia64/kernel/cpe_migrate.c	2008-06-09 09:26:56.980173332 -0500
@@ -0,0 +1,419 @@
+/*
+ * File:	cpe_migrate.c
+ * Purpose:	Migrate data from physical pages with excessive correctable
+ *		errors to new physical pages.  Keep the old pages on a discard
+ *		list.
+ *
+ * Copyright (C) 2008 SGI - Silicon Graphics Inc.
+ * Copyright (C) 2008 Russ Anderson <rja@xxxxxxx>
+ */
+
+#include <linux/sysdev.h>
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/smp.h>
+#include <linux/workqueue.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/vmalloc.h>
+#include <linux/migrate.h>
+#include <linux/page-isolation.h>
+#include <linux/memcontrol.h>
+#include <linux/kobject.h>
+
+#include <asm/page.h>
+#include <asm/system.h>
+#include <asm/sn/sn_cpuid.h>
+#include <asm/mca.h>
+
+#define BADRAM_BASENAME		"badram"
+#define CE_HISTORY_LENGTH	30
+
+struct cpe_info {
+	u64 	paddr;
+	u16	node;
+};
+static struct cpe_info cpe[CE_HISTORY_LENGTH];
+
+static int cpe_polling_enabled = 1;
+static int cpe_head;
+static int cpe_tail;
+static int work_scheduled;
+
+DEFINE_SPINLOCK(cpe_migrate_lock);
+
+static void
+get_physical_address(void *buffer, u64 *paddr, u16 *node)
+{
+	sal_log_record_header_t *rh;
+	sal_log_mem_dev_err_info_t *mdei;
+	ia64_err_rec_t *err_rec;
+	sal_log_platform_err_info_t *plat_err;
+	efi_guid_t guid;
+
+	err_rec = buffer;
+	rh = &err_rec->sal_elog_header;
+	*paddr = 0;
+	*node = 0;
+
+	/*
+	 * Make sure it is a corrected error.
+	 */
+	if (rh->severity != sal_log_severity_corrected)
+		return;
+
+	plat_err = (sal_log_platform_err_info_t *)&err_rec->proc_err;
+
+	guid = plat_err->mem_dev_err.header.guid;
+	if (efi_guidcmp(guid, SAL_PLAT_MEM_DEV_ERR_SECT_GUID) == 0) {
+		/*
+		 * Memory cpe
+		 */
+		mdei = &plat_err->mem_dev_err;
+		if (mdei->valid.oem_data) {
+			if (mdei->valid.physical_addr)
+				*paddr = mdei->physical_addr;
+
+			if (mdei->valid.node) {
+				if (ia64_platform_is("sn2"))
+					*node = nasid_to_cnodeid(mdei->node);
+				else
+					*node = mdei->node;
+			}
+		}
+	}
+}
+
+static struct page *
+alloc_migrate_page(struct page *ignored, unsigned long node, int **x)
+{
+
+	return alloc_pages_node(node, GFP_HIGHUSER_MOVABLE, 0);
+}
+
+static int
+validate_paddr_page(u64 paddr)
+{
+	struct page *page;
+
+	if (!paddr)
+		return -EINVAL;
+
+	if (!ia64_phys_addr_valid(paddr))
+		return -EINVAL;
+
+	if (!pfn_valid(paddr >> PAGE_SHIFT))
+		return -EINVAL;
+
+	page = phys_to_page(paddr);
+	if (PageMemError(page))
+		/*
+		 * The page has already been marked bad.
+		 */
+		return -EINVAL;
+	return 0;
+}
+
+static int
+ia64_mca_cpe_move_page(u64 paddr, u32 node)
+{
+	LIST_HEAD(pagelist);
+	struct page *page;
+	int ret;
+
+	ret = validate_paddr_page(paddr);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * convert physical address to page number
+	 */
+	page = phys_to_page(paddr);
+
+	migrate_prep();
+	ret = isolate_lru_page(page, &pagelist);
+	if (ret)
+		return ret;
+
+	SetPageMemError(page);		/* Mark the page as bad */
+	ret = migrate_pages(&pagelist, alloc_migrate_page, node);
+	if (ret == 0) {
+		total_badpages++;
+		list_add_tail(&page->lru, &badpagelist);
+	} else
+		/*
+		 * The page failed to migrate and is not on the bad page list.
+		 * Clearing the error bit will allow another attempt to migrate
+		 * if it gets another correctable error.
+		 */
+		ClearPageMemError(page);
+
+	return 0;
+}
+
+/*
+ * ia64_mca_cpe_migrate
+ *	The worker that does the actual migration.  It pulls a
+ *	physical address off the list and calls the migration code.
+ */
+static void
+ia64_mca_cpe_migrate(struct work_struct *unused)
+{
+	int ret;
+	u64 paddr;
+	u16 node;
+
+	do {
+		paddr = cpe[cpe_tail].paddr;
+		if (paddr) {
+			/*
+			 * There is a valid entry that needs processing.
+			 */
+			node = cpe[cpe_tail].node;
+
+			ret = ia64_mca_cpe_move_page(paddr, node);
+			if (ret <= 0)
+				/*
+				 * Even though the return status is negative,
+				 * clear the entry.  If the same address has
+				 * another CPE it will be re-added to the list.
+				 */
+				cpe[cpe_tail].paddr = 0;
+
+		}
+		if (++cpe_tail >= CE_HISTORY_LENGTH)
+			cpe_tail = 0;
+
+	} while (cpe_tail != cpe_head);
+	work_scheduled = 0;
+}
+
+static DECLARE_WORK(cpe_enable_work, ia64_mca_cpe_migrate);
+DEFINE_SPINLOCK(cpe_list_lock);
+
+/*
+ * cpe_setup_migrate
+ *	Get the physical address out of the CPE record, add it
+ *	to the list of addresses to migrate (if not already on),
+ *	and schedule the back end worker task.  This is called
+ *	in interrupt context so cannot directly call the migration
+ *	code.
+ *
+ *  Inputs
+ *	rec	The CPE record
+ *  Outputs
+ *	1 on Success, -1 on failure
+ */
+static int
+cpe_setup_migrate(void *rec)
+{
+	u64 paddr;
+	u16 node;
+	/* int head, tail; */
+	int i, ret;
+
+	if (!rec)
+		return -EINVAL;
+
+	get_physical_address(rec, &paddr, &node);
+	ret = validate_paddr_page(paddr);
+	if (ret < 0)
+		return -EINVAL;
+
+	if ((cpe_head != cpe_tail) || (cpe[cpe_head].paddr != 0))
+		/*
+		 * List not empty
+		 */
+		for (i = 0; i < CE_HISTORY_LENGTH; i++) {
+			if (PAGE_ALIGN(cpe[i].paddr) == PAGE_ALIGN(paddr))
+				return 1;	/* already on the list */
+		}
+
+	if (!spin_trylock(&cpe_list_lock)) {
+		/*
+		 * Someone else has the lock.  To avoid spinning in interrupt
+		 * handler context, bail.
+		 */
+		return 1;
+	}
+
+	if (cpe[cpe_head].paddr == 0) {
+		cpe[cpe_head].node = node;
+		cpe[cpe_head].paddr = paddr;
+
+		if (++cpe_head >= CE_HISTORY_LENGTH)
+			cpe_head = 0;
+	}
+	spin_unlock(&cpe_list_lock);
+
+	if (!work_scheduled) {
+		work_scheduled = 1;
+		schedule_work(&cpe_enable_work);
+	}
+
+	return 1;
+}
+
+/*
+ * =============================================================================
+ */
+
+/*
+ * free_one_bad_page
+ *	Free one page from the list of bad pages.
+ */
+static int
+free_one_bad_page(unsigned long paddr)
+{
+	LIST_HEAD(pagelist);
+	struct page *page, *page2, *target;
+
+	/*
+	 * Verify page address
+	 */
+	target = phys_to_page(paddr);
+	list_for_each_entry_safe(page, page2, &badpagelist, lru) {
+		if (page != target)
+			continue;
+
+		ClearPageMemError(page);        /* Mark the page as good */
+		total_badpages--;
+		list_move_tail(&page->lru, &pagelist);
+		putback_lru_pages(&pagelist);
+		break;
+	}
+	return 0;
+}
+
+/*
+ * free_all_bad_pages
+ *	Free all of the pages on the bad pages list.
+ */
+static int
+free_all_bad_pages(void)
+{
+	struct page *page, *page2;
+
+	list_for_each_entry_safe(page, page2, &badpagelist, lru) {
+		ClearPageMemError(page);        /* Mark the page as good */
+		total_badpages--;
+	}
+	putback_lru_pages(&badpagelist);
+	return 0;
+}
+
+#define OPT_LEN	16
+
+static ssize_t
+badpage_store(struct kobject *kobj,
+	      struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	char optstr[OPT_LEN];
+	unsigned long opt;
+	int len = OPT_LEN;
+	int err;
+
+	if (count < len)
+		len = count;
+
+	strlcpy(optstr, buf, len);
+
+	err = strict_strtoul(optstr, 16, &opt);
+	if (err)
+		return err;
+
+	if (opt == 0)
+		free_all_bad_pages();
+	else
+		free_one_bad_page(opt);
+
+	return count;
+}
+
+/*
+ * badpage_show
+ *	Display the number, size, and addresses of all the pages on the
+ *	bad page list.
+ *
+ *	Note that sysfs provides buf of PAGE_SIZE length.  bufend tracks
+ *	the remaining space in buf to avoid overflowing.
+ */
+static ssize_t
+badpage_show(struct kobject *kobj,
+	     struct kobj_attribute *attr, char *buf)
+
+{
+	struct page *page, *page2;
+	int i = 0, cnt = 0;
+	char *bufend = buf + PAGE_SIZE;
+
+	cnt = snprintf(buf, bufend - (buf + cnt),
+			"Bad RAM: %d kB, %d pages marked bad\n"
+			"List of bad physical pages\n",
+			total_badpages << (PAGE_SHIFT - 10), total_badpages);
+
+	list_for_each_entry_safe(page, page2, &badpagelist, lru) {
+		if (bufend - (buf + cnt) < 20)
+			break;		/* Avoid overflowing the buffer */
+		cnt += snprintf(buf + cnt, bufend - (buf + cnt),
+				" 0x%011lx", page_to_phys(page));
+		if (!(++i % 5))
+			cnt += snprintf(buf + cnt, bufend - (buf + cnt), "\n");
+	}
+	cnt += snprintf(buf + cnt, bufend - (buf + cnt), "\n");
+
+	return cnt;
+}
+
+static struct kobj_attribute badram_attr = {
+	.attr    = {
+		.name = "badram",
+		.mode = S_IWUSR | S_IRUGO,
+	},
+	.show = badpage_show,
+	.store = badpage_store,
+};
+
+static int __init
+cpe_migrate_external_handler_init(void)
+{
+	int error;
+
+	error = sysfs_create_file(kernel_kobj, &badram_attr.attr);
+	if (error)
+		return -EINVAL;
+
+	/*
+	 * register external ce handler
+	 */
+	if (ia64_reg_CE_extension(cpe_setup_migrate)) {
+		printk(KERN_ERR "ia64_reg_CE_extension failed.\n");
+		return -EFAULT;
+	}
+	cpe_poll_enabled = cpe_polling_enabled;
+
+	printk(KERN_INFO "Registered badram Driver\n");
+	return 0;
+}
+
+static void __exit
+cpe_migrate_external_handler_exit(void)
+{
+	/* unregister external mca handlers */
+	ia64_unreg_CE_extension();
+
+	sysfs_remove_file(kernel_kobj, &badram_attr.attr);
+}
+
+module_init(cpe_migrate_external_handler_init);
+module_exit(cpe_migrate_external_handler_exit);
+
+module_param(cpe_polling_enabled, int, 0644);
+MODULE_PARM_DESC(cpe_polling_enabled,
+		"Enable polling with migration");
+
+MODULE_AUTHOR("Russ Anderson <rja@xxxxxxx>");
+MODULE_DESCRIPTION("ia64 Corrected Error page migration driver");
+MODULE_LICENSE("GPL");
Index: linux-next/arch/ia64/kernel/mca.c
===================================================================
--- linux-next.orig/arch/ia64/kernel/mca.c	2008-06-09 09:26:44.750649655 -0500
+++ linux-next/arch/ia64/kernel/mca.c	2008-06-09 09:26:57.000175824 -0500
@@ -68,6 +68,9 @@
  *
  * 2007-04-27 Russ Anderson <rja@xxxxxxx>
  *	      Support multiple cpus going through OS_MCA in the same event.
+ *
+ * 2008-04-22 Russ Anderson <rja@xxxxxxx>
+ *	      Migrate data off pages with correctable memory errors.
  */
 #include <linux/jiffies.h>
 #include <linux/types.h>
@@ -163,7 +166,14 @@ static int cmc_polling_enabled = 1;
  * but encounters problems retrieving CPE logs.  This should only be
  * necessary for debugging.
  */
-static int cpe_poll_enabled = 1;
+int cpe_poll_enabled = 1;
+EXPORT_SYMBOL(cpe_poll_enabled);
+
+unsigned int total_badpages;
+EXPORT_SYMBOL(total_badpages);
+
+LIST_HEAD(badpagelist);
+EXPORT_SYMBOL(badpagelist);
 
 extern void salinfo_log_wakeup(int type, u8 *buffer, u64 size, int irqsafe);
 
@@ -523,6 +533,28 @@ int mca_recover_range(unsigned long addr
 }
 EXPORT_SYMBOL_GPL(mca_recover_range);
 
+/* Function pointer to Corrected Error memory migration driver */
+int (*ia64_mca_ce_extension)(void *);
+
+int
+ia64_reg_CE_extension(int (*fn)(void *))
+{
+	if (ia64_mca_ce_extension)
+		return 1;
+
+	ia64_mca_ce_extension = fn;
+	return 0;
+}
+EXPORT_SYMBOL(ia64_reg_CE_extension);
+
+void
+ia64_unreg_CE_extension(void)
+{
+	if (ia64_mca_ce_extension)
+		ia64_mca_ce_extension = NULL;
+}
+EXPORT_SYMBOL(ia64_unreg_CE_extension);
+
 #ifdef CONFIG_ACPI
 
 int cpe_vector = -1;
@@ -534,6 +566,7 @@ ia64_mca_cpe_int_handler (int cpe_irq, v
 	static unsigned long	cpe_history[CPE_HISTORY_LENGTH];
 	static int		index;
 	static DEFINE_SPINLOCK(cpe_history_lock);
+	int recover;
 
 	IA64_MCA_DEBUG("%s: received interrupt vector = %#x on CPU %d\n",
 		       __func__, cpe_irq, smp_processor_id());
@@ -580,6 +613,8 @@ ia64_mca_cpe_int_handler (int cpe_irq, v
 out:
 	/* Get the CPE error record and log it */
 	ia64_mca_log_sal_error_record(SAL_INFO_TYPE_CPE);
+	recover = (ia64_mca_ce_extension && ia64_mca_ce_extension(
+				IA64_LOG_CURR_BUFFER(SAL_INFO_TYPE_CPE)));
 
 	return IRQ_HANDLED;
 }
Index: linux-next/arch/ia64/Kconfig
===================================================================
--- linux-next.orig/arch/ia64/Kconfig	2008-06-09 09:26:44.750649655 -0500
+++ linux-next/arch/ia64/Kconfig	2008-06-09 09:26:57.024178815 -0500
@@ -469,6 +469,15 @@ config COMPAT_FOR_U64_ALIGNMENT
 config IA64_MCA_RECOVERY
 	tristate "MCA recovery from errors other than TLB."
 
+config IA64_CPE_MIGRATE
+	tristate "Migrate data off pages with correctable errors"
+	default m
+	help
+	  Migrate data off pages with correctable memory errors.  Selecting
+	  Y will build this functionality into the kernel.  Selecting M will
+	  build this functionality as a kernel loadable module.  Installing
+	  the module will turn on the functionality.
+
 config PERFMON
 	bool "Performance monitor support"
 	help
Index: linux-next/include/asm-ia64/mca.h
===================================================================
--- linux-next.orig/include/asm-ia64/mca.h	2008-06-09 09:26:44.750649655 -0500
+++ linux-next/include/asm-ia64/mca.h	2008-06-09 09:26:57.048181805 -0500
@@ -137,6 +137,7 @@ extern unsigned long __per_cpu_mca[NR_CP
 
 extern int cpe_vector;
 extern int ia64_cpe_irq;
+extern int cpe_poll_enabled;
 extern void ia64_mca_init(void);
 extern void ia64_mca_cpu_init(void *);
 extern void ia64_os_mca_dispatch(void);
@@ -150,9 +151,14 @@ extern void ia64_slave_init_handler(void
 extern void ia64_mca_cmc_vector_setup(void);
 extern int  ia64_reg_MCA_extension(int (*fn)(void *, struct ia64_sal_os_state *));
 extern void ia64_unreg_MCA_extension(void);
+extern int  ia64_reg_CE_extension(int (*fn)(void *));
+extern void ia64_unreg_CE_extension(void);
 extern u64 ia64_get_rnat(u64 *);
 extern void ia64_mca_printk(const char * fmt, ...)
 	 __attribute__ ((format (printf, 1, 2)));
+
+extern struct list_head badpagelist;
+extern unsigned int total_badpages;
 
 struct ia64_mca_notify_die {
 	struct ia64_sal_os_state *sos;
Index: linux-next/include/asm-ia64/page.h
===================================================================
--- linux-next.orig/include/asm-ia64/page.h	2008-06-09 09:26:44.750649655 -0500
+++ linux-next/include/asm-ia64/page.h	2008-06-09 09:26:57.072184796 -0500
@@ -122,6 +122,7 @@ extern unsigned long max_low_pfn;
 #endif
 
 #define page_to_phys(page)	(page_to_pfn(page) << PAGE_SHIFT)
+#define phys_to_page(kaddr)	(pfn_to_page(kaddr >> PAGE_SHIFT))
 #define virt_to_page(kaddr)	pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
 #define pfn_to_kaddr(pfn)	__va((pfn) << PAGE_SHIFT)
 
Index: linux-next/mm/migrate.c
===================================================================
--- linux-next.orig/mm/migrate.c	2008-06-09 09:26:54.739894217 -0500
+++ linux-next/mm/migrate.c	2008-06-09 09:26:57.092187288 -0500
@@ -64,6 +64,7 @@ int isolate_lru_page(struct page *page, 
 	}
 	return ret;
 }
+EXPORT_SYMBOL(isolate_lru_page);
 
 /*
  * migrate_prep() needs to be called before we start compiling a list of pages
@@ -81,6 +82,7 @@ int migrate_prep(void)
 
 	return 0;
 }
+EXPORT_SYMBOL(migrate_prep);
 
 static inline void move_to_lru(struct page *page)
 {
@@ -115,6 +117,7 @@ int putback_lru_pages(struct list_head *
 	}
 	return count;
 }
+EXPORT_SYMBOL(putback_lru_pages);
 
 /*
  * Restore a potential migration pte to a working pte entry
@@ -831,6 +834,7 @@ out:
 
 	return nr_failed + retry;
 }
+EXPORT_SYMBOL(migrate_pages);
 
 #ifdef CONFIG_NUMA
 /*
-- 
Russ Anderson, OS RAS/Partitioning Project Lead  
SGI - Silicon Graphics Inc          rja@xxxxxxx
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