Date:	Mon, 28 Apr 2008 14:24:57 -0500
From:	Russ Anderson <rja@....com>
To:	linux-kernel@...r.kernel.org, linux-ia64@...r.kernel.org
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Tony Luck <tony.luck@...el.com>,
	Christoph Lameter <clameter@....com>,
	Russ Anderson <rja@....com>
Subject: [PATCH 2/2] ia64: Call migration code on correctable errors

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.  

It exports three symbols (migrate_prep, isolate_lru_page, and migrate_pages).

Signed-off-by: Russ Anderson <rja@....com>

---
 arch/ia64/Kconfig              |    3 
 arch/ia64/kernel/Makefile      |    1 
 arch/ia64/kernel/cpe_migrate.c |  275 +++++++++++++++++++++++++++++++++++++++++
 arch/ia64/kernel/mca.c         |   34 ++++-
 include/asm-ia64/mca.h         |    3 
 include/asm-ia64/page.h        |    1 
 mm/migrate.c                   |    3 
 7 files changed, 319 insertions(+), 1 deletion(-)

Index: test/arch/ia64/kernel/Makefile
===================================================================
--- test.orig/arch/ia64/kernel/Makefile	2008-04-28 13:27:48.682600987 -0500
+++ test/arch/ia64/kernel/Makefile	2008-04-28 13:27:56.511575718 -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: test/arch/ia64/kernel/cpe_migrate.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ test/arch/ia64/kernel/cpe_migrate.c	2008-04-28 13:27:56.523577213 -0500
@@ -0,0 +1,275 @@
+/*
+ * 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@....com>
+ */
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/kallsyms.h>
+#include <linux/bootmem.h>
+#include <linux/acpi.h>
+#include <linux/timer.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/delay.h>
+#include <linux/ptrace.h>
+#include <linux/irq.h>
+#include <linux/vmalloc.h>
+#include <linux/migrate.h>
+#include <linux/page-isolation.h>
+#include <linux/rmap.h>
+#include <linux/memcontrol.h>
+
+#include <asm/machvec.h>
+#include <asm/page.h>
+#include <asm/system.h>
+#include <asm/sal.h>
+#include <asm/hw_irq.h>
+#include <asm/sn/sn_cpuid.h>
+#include <asm/mca.h>
+
+#define CE_HISTORY_LENGTH	30
+
+static u64 cpe_paddr[CE_HISTORY_LENGTH];
+static u16 cpe_node[CE_HISTORY_LENGTH];
+static int cpe_polling_enabled = 1;
+static int cpe_head;
+static int cpe_tail;
+
+int work_scheduled;
+spinlock_t cpe_migrate_lock;
+
+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 = (ia64_err_rec_t *)buffer;
+	rh = (sal_log_record_header_t *)&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 = (efi_guid_t)plat_err->mem_dev_err.header.guid;
+	if (efi_guidcmp(guid, SAL_PLAT_MEM_DEV_ERR_SECT_GUID) == 0) {
+		/*
+		 * Memory cpe
+		 */
+		mdei = (sal_log_mem_dev_err_info_t *)&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;
+			}
+			return;
+		}
+	}
+	return;
+}
+
+struct page *
+alloc_migrate_page(struct page *ignored, unsigned long node, int **x)
+{
+
+	return alloc_pages_node(node, GFP_HIGHUSER_MOVABLE, 0);
+}
+
+static int
+ia64_mca_cpe_move_page(u64 paddr, u32 node)
+{
+	LIST_HEAD(pagelist);
+	struct page *page;
+	int ret;
+	unsigned long irq_flags;
+	extern struct list_head badpagelist;
+
+	local_irq_save(irq_flags);
+	/*
+	 * Validate page
+	 */
+	if (!paddr)
+		return -1;
+	if (!ia64_phys_addr_valid(paddr))
+		return -1;
+	if (!pfn_valid(paddr >> PAGE_SHIFT))
+		return -1;
+
+	/*
+	 * convert physical address to page number
+	 */
+	page = phys_to_page(paddr);
+
+	if (!spin_trylock(&cpe_migrate_lock)) {
+		local_irq_restore(irq_flags);
+		return -1;
+	}
+
+	preempt_disable();
+	migrate_prep();
+	ret = isolate_lru_page(page, &pagelist);
+	preempt_enable();
+	if (ret) {
+		spin_unlock_irqrestore(&cpe_migrate_lock, irq_flags);
+		return ret;
+	}
+
+	SetPageMemError(page);		/* Mark the page as bad */
+	ret = migrate_pages(&pagelist, alloc_migrate_page, node);
+	if (ret == 0)
+		list_add_tail(&page->lru, &badpagelist);
+
+	spin_unlock_irqrestore(&cpe_migrate_lock, irq_flags);
+	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.
+ *
+ *  Inputs
+ *	none
+ *  Outputs
+ *	none
+ */
+static void
+ia64_mca_cpe_migrate(struct work_struct *unused)
+{
+	int ret;
+	u64 paddr;
+	u16 node;
+
+	do {
+		if (cpe_paddr[cpe_tail]) {
+			paddr = cpe_paddr[cpe_tail];
+			node = cpe_node[cpe_tail];
+
+			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_paddr[cpe_tail] = 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);
+
+/*
+ * ce_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
+ce_setup_migrate(void *rec)
+{
+	u64 paddr;
+	u16 node;
+	/* int head, tail; */
+	int i;
+
+	if (!rec)
+		return -1;
+
+	get_physical_address(rec, &paddr, &node);
+	if (!paddr)
+		return -1;
+
+	if (!((cpe_head == cpe_tail) && (cpe_paddr[cpe_head] == 0)))
+		/*
+		 * List not empty
+		 */
+		for (i = 0; i < CE_HISTORY_LENGTH; i++)
+			if ((PAGE_ALIGN(cpe_paddr[i])) == PAGE_ALIGN(paddr))
+				return 1;	/* already on the list */
+
+	if (cpe_paddr[cpe_head] == 0) {
+		cpe_paddr[cpe_head] = paddr;
+		cpe_node[cpe_head] = node;
+
+		if (++cpe_head >= CE_HISTORY_LENGTH)
+			cpe_head = 0;
+	}
+
+	if (!work_scheduled) {
+		work_scheduled = 1;
+		schedule_work(&cpe_enable_work);
+	}
+
+	return 1;
+}
+
+/*
+ * =============================================================================
+ */
+
+int __init cpe_migrate_external_handler_init(void)
+{
+	spin_lock_init(&cpe_migrate_lock);
+
+	/* register external ce handler */
+	if (ia64_reg_CE_extension(ce_setup_migrate)) {
+		printk(KERN_ERR "ia64_reg_CE_extension failed.\n");
+		return -EFAULT;
+	}
+	cpe_poll_enabled = cpe_polling_enabled;
+	return 0;
+}
+
+void __exit cpe_migrate_external_handler_exit(void)
+{
+	/* unregister external mca handlers */
+	ia64_unreg_CE_extension();
+}
+
+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_DESCRIPTION("ia64 Corrected Error page migration driver");
+MODULE_LICENSE("GPL");
Index: test/arch/ia64/kernel/mca.c
===================================================================
--- test.orig/arch/ia64/kernel/mca.c	2008-04-28 13:27:48.682600987 -0500
+++ test/arch/ia64/kernel/mca.c	2008-04-28 13:27:56.543579703 -0500
@@ -68,6 +68,9 @@
  *
  * 2007-04-27 Russ Anderson <rja@....com>
  *	      Support multiple cpus going through OS_MCA in the same event.
+ *
+ * 2008-04-22 Russ Anderson <rja@....com>
+ *	      Migrate data off pages with correctable memory errors.
  */
 #include <linux/jiffies.h>
 #include <linux/types.h>
@@ -163,7 +166,11 @@ 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);
+
+LIST_HEAD(badpagelist);
+EXPORT_SYMBOL(badpagelist);
 
 extern void salinfo_log_wakeup(int type, u8 *buffer, u64 size, int irqsafe);
 
@@ -525,6 +532,28 @@ EXPORT_SYMBOL_GPL(mca_recover_range);
 
 #ifdef CONFIG_ACPI
 
+/* Function pointer to Corrected Error memory migration driver */
+int (*ia64_mca_ce_extension)(void *) = NULL;
+
+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);
+
 int cpe_vector = -1;
 int ia64_cpe_irq = -1;
 
@@ -534,6 +563,7 @@ 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 +610,8 @@ 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: test/arch/ia64/Kconfig
===================================================================
--- test.orig/arch/ia64/Kconfig	2008-04-28 13:27:48.682600987 -0500
+++ test/arch/ia64/Kconfig	2008-04-28 13:27:56.575583688 -0500
@@ -451,6 +451,9 @@ 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"
+
 config PERFMON
 	bool "Performance monitor support"
 	help
Index: test/include/asm-ia64/mca.h
===================================================================
--- test.orig/include/asm-ia64/mca.h	2008-04-28 13:27:48.682600987 -0500
+++ test/include/asm-ia64/mca.h	2008-04-28 13:27:56.591585680 -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);
@@ -150,6 +151,8 @@ 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)));
Index: test/mm/migrate.c
===================================================================
--- test.orig/mm/migrate.c	2008-04-28 13:27:48.686601486 -0500
+++ test/mm/migrate.c	2008-04-28 13:27:56.615588668 -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)
 {
@@ -798,6 +800,7 @@ out:
 
 	return nr_failed + retry;
 }
+EXPORT_SYMBOL(migrate_pages);
 
 #ifdef CONFIG_NUMA
 /*
Index: test/include/asm-ia64/page.h
===================================================================
--- test.orig/include/asm-ia64/page.h	2008-04-28 13:27:48.682600987 -0500
+++ test/include/asm-ia64/page.h	2008-04-28 13:27:56.639591657 -0500
@@ -125,6 +125,7 @@ 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)
 
-- 
Russ Anderson, OS RAS/Partitioning Project Lead  
SGI - Silicon Graphics Inc          rja@....com
--
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