ACPI, x86: Extended error log driver for x86 platform

This H/W error log driver (a.k.a eMCA driver) is implemented based on
http://www.intel.com/content/www/us/en/architecture-and-technology/enhanced-mca-logging-xeon-paper.html

After errors are captured, more detailed platform specific information
can be got via this new enhanced H/W error log driver. Most notably we
can track memory errors back to the DIMM slot silk screen label.

Signed-off-by: Chen, Gong <[e-mail]>
Signed-off-by: Tony Luck <[e-mail]>

arch/x86/include/asm/mce.h

···
 #define MCG_EXT_CNT_SHIFT	16
 #define MCG_EXT_CNT(c)		(((c) & MCG_EXT_CNT_MASK) >> MCG_EXT_CNT_SHIFT)
 #define MCG_SER_P		(1ULL<<24)   /* MCA recovery/new status bits */
+#define MCG_ELOG_P		(1ULL<<26)   /* Extended error log supported */
 
 /* MCG_STATUS register defines */
 #define MCG_STATUS_RIPV  (1ULL<<0)   /* restart ip valid */

drivers/acpi/Kconfig

···
 
 source "drivers/acpi/apei/Kconfig"
 
+config ACPI_EXTLOG
+	tristate "Extended Error Log support"
+	depends on X86_MCE && ACPI_APEI
+	default n
+	help
+	  Certain usages such as Predictive Failure Analysis (PFA) require
+	  more information about the error than what can be described in
+	  processor machine check banks. Most server processors log
+	  additional information about the error in processor uncore
+	  registers. Since the addresses and layout of these registers vary
+	  widely from one processor to another, system software cannot
+	  readily make use of them. To complicate matters further, some of
+	  the additional error information cannot be constructed without
+	  detailed knowledge about platform topology.
+
+	  Enhanced MCA Logging allows firmware to provide additional error
+	  information to system software, synchronous with MCE or CMCI. This
+	  driver adds support for that functionality.
+
 endif	# ACPI

drivers/acpi/Makefile

···
 obj-$(CONFIG_ACPI_PROCESSOR_AGGREGATOR) += acpi_pad.o
 
 obj-$(CONFIG_ACPI_APEI)		+= apei/
+
+obj-$(CONFIG_ACPI_EXTLOG)	+= acpi_extlog.o

drivers/acpi/acpi_extlog.c

···
+/*
+ * Extended Error Log driver
+ *
+ * Copyright (C) 2013 Intel Corp.
+ * Author: Chen, Gong <[e-mail]>
+ *
+ * This file is licensed under GPLv2.
+ */
+
+#include <linux/module.h>
+#include <linux/acpi.h>
+#include <acpi/acpi_bus.h>
+#include <linux/cper.h>
+#include <linux/ratelimit.h>
+#include <asm/cpu.h>
+#include <asm/mce.h>
+
+#include "apei/apei-internal.h"
+
+#define EXT_ELOG_ENTRY_MASK	GENMASK_ULL(51, 0) /* elog entry address mask */
+
+#define EXTLOG_DSM_REV		0x0
+#define	EXTLOG_FN_QUERY		0x0
+#define	EXTLOG_FN_ADDR		0x1
+
+#define FLAG_OS_OPTIN		BIT(0)
+#define EXTLOG_QUERY_L1_EXIST	BIT(1)
+#define ELOG_ENTRY_VALID	(1ULL<<63)
+#define ELOG_ENTRY_LEN		0x1000
+
+#define EMCA_BUG \
+	"Can not request iomem region <0x%016llx-0x%016llx> - eMCA disabled\n"
+
+struct extlog_l1_head {
+	u32 ver;	/* Header Version */
+	u32 hdr_len;	/* Header Length */
+	u64 total_len;	/* entire L1 Directory length including this header */
+	u64 elog_base;	/* MCA Error Log Directory base address */
+	u64 elog_len;	/* MCA Error Log Directory length */
+	u32 flags;	/* bit 0 - OS/VMM Opt-in */
+	u8  rev0[12];
+	u32 entries;	/* Valid L1 Directory entries per logical processor */
+	u8  rev1[12];
+};
+
+static u8 extlog_dsm_uuid[] = "663E35AF-CC10-41A4-88EA-5470AF055295";
+
+/* L1 table related physical address */
+static u64 elog_base;
+static size_t elog_size;
+static u64 l1_dirbase;
+static size_t l1_size;
+
+/* L1 table related virtual address */
+static void __iomem *extlog_l1_addr;
+static void __iomem *elog_addr;
+
+static void *elog_buf;
+
+static u64 *l1_entry_base;
+static u32 l1_percpu_entry;
+
+#define ELOG_IDX(cpu, bank) \
+	(cpu_physical_id(cpu) * l1_percpu_entry + (bank))
+
+#define ELOG_ENTRY_DATA(idx) \
+	(*(l1_entry_base + (idx)))
+
+#define ELOG_ENTRY_ADDR(phyaddr) \
+	(phyaddr - elog_base + (u8 *)elog_addr)
+
+static struct acpi_generic_status *extlog_elog_entry_check(int cpu, int bank)
+{
+	int idx;
+	u64 data;
+	struct acpi_generic_status *estatus;
+
+	WARN_ON(cpu < 0);
+	idx = ELOG_IDX(cpu, bank);
+	data = ELOG_ENTRY_DATA(idx);
+	if ((data & ELOG_ENTRY_VALID) == 0)
+		return NULL;
+
+	data &= EXT_ELOG_ENTRY_MASK;
+	estatus = (struct acpi_generic_status *)ELOG_ENTRY_ADDR(data);
+
+	/* if no valid data in elog entry, just return */
+	if (estatus->block_status == 0)
+		return NULL;
+
+	return estatus;
+}
+
+static void __print_extlog_rcd(const char *pfx,
+			       struct acpi_generic_status *estatus, int cpu)
+{
+	static atomic_t seqno;
+	unsigned int curr_seqno;
+	char pfx_seq[64];
+
+	if (!pfx) {
+		if (estatus->error_severity <= CPER_SEV_CORRECTED)
+			pfx = KERN_INFO;
+		else
+			pfx = KERN_ERR;
+	}
+	curr_seqno = atomic_inc_return(&seqno);
+	snprintf(pfx_seq, sizeof(pfx_seq), "%s{%u}", pfx, curr_seqno);
+	printk("%s""Hardware error detected on CPU%d\n", pfx_seq, cpu);
+	cper_estatus_print(pfx_seq, estatus);
+}
+
+static int print_extlog_rcd(const char *pfx,
+			    struct acpi_generic_status *estatus, int cpu)
+{
+	/* Not more than 2 messages every 5 seconds */
+	static DEFINE_RATELIMIT_STATE(ratelimit_corrected, 5*HZ, 2);
+	static DEFINE_RATELIMIT_STATE(ratelimit_uncorrected, 5*HZ, 2);
+	struct ratelimit_state *ratelimit;
+
+	if (estatus->error_severity == CPER_SEV_CORRECTED ||
+	    (estatus->error_severity == CPER_SEV_INFORMATIONAL))
+		ratelimit = &ratelimit_corrected;
+	else
+		ratelimit = &ratelimit_uncorrected;
+	if (__ratelimit(ratelimit)) {
+		__print_extlog_rcd(pfx, estatus, cpu);
+		return 0;
+	}
+
+	return 1;
+}
+
+static int extlog_print(struct notifier_block *nb, unsigned long val,
+			void *data)
+{
+	struct mce *mce = (struct mce *)data;
+	int	bank = mce->bank;
+	int	cpu = mce->extcpu;
+	struct acpi_generic_status *estatus;
+	int rc;
+
+	estatus = extlog_elog_entry_check(cpu, bank);
+	if (estatus == NULL)
+		return NOTIFY_DONE;
+
+	memcpy(elog_buf, (void *)estatus, ELOG_ENTRY_LEN);
+	/* clear record status to enable BIOS to update it again */
+	estatus->block_status = 0;
+
+	rc = print_extlog_rcd(NULL, (struct acpi_generic_status *)elog_buf, cpu);
+
+	return NOTIFY_DONE;
+}
+
+static int extlog_get_dsm(acpi_handle handle, int rev, int func, u64 *ret)
+{
+	struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
+	struct acpi_object_list input;
+	union acpi_object params[4], *obj;
+	u8 uuid[16];
+	int i;
+
+	acpi_str_to_uuid(extlog_dsm_uuid, uuid);
+	input.count = 4;
+	input.pointer = params;
+	params[0].type = ACPI_TYPE_BUFFER;
+	params[0].buffer.length = 16;
+	params[0].buffer.pointer = uuid;
+	params[1].type = ACPI_TYPE_INTEGER;
+	params[1].integer.value = rev;
+	params[2].type = ACPI_TYPE_INTEGER;
+	params[2].integer.value = func;
+	params[3].type = ACPI_TYPE_PACKAGE;
+	params[3].package.count = 0;
+	params[3].package.elements = NULL;
+
+	if (ACPI_FAILURE(acpi_evaluate_object(handle, "_DSM", &input, &buf)))
+		return -1;
+
+	*ret = 0;
+	obj = (union acpi_object *)buf.pointer;
+	if (obj->type == ACPI_TYPE_INTEGER) {
+		*ret = obj->integer.value;
+	} else if (obj->type == ACPI_TYPE_BUFFER) {
+		if (obj->buffer.length <= 8) {
+			for (i = 0; i < obj->buffer.length; i++)
+				*ret |= (obj->buffer.pointer[i] << (i * 8));
+		}
+	}
+	kfree(buf.pointer);
+
+	return 0;
+}
+
+static bool extlog_get_l1addr(void)
+{
+	acpi_handle handle;
+	u64 ret;
+
+	if (ACPI_FAILURE(acpi_get_handle(NULL, "\\_SB", &handle)))
+		return false;
+
+	if (extlog_get_dsm(handle, EXTLOG_DSM_REV, EXTLOG_FN_QUERY, &ret) ||
+	    !(ret & EXTLOG_QUERY_L1_EXIST))
+		return false;
+
+	if (extlog_get_dsm(handle, EXTLOG_DSM_REV, EXTLOG_FN_ADDR, &ret))
+		return false;
+
+	l1_dirbase = ret;
+	/* Spec says L1 directory must be 4K aligned, bail out if it isn't */
+	if (l1_dirbase & ((1 << 12) - 1)) {
+		pr_warn(FW_BUG "L1 Directory is invalid at physical %llx\n",
+			l1_dirbase);
+		return false;
+	}
+
+	return true;
+}
+static struct notifier_block extlog_mce_dec = {
+	.notifier_call	= extlog_print,
+};
+
+static int __init extlog_init(void)
+{
+	struct extlog_l1_head *l1_head;
+	void __iomem *extlog_l1_hdr;
+	size_t l1_hdr_size;
+	struct resource *r;
+	u64 cap;
+	int rc;
+
+	rc = -ENODEV;
+
+	rdmsrl(MSR_IA32_MCG_CAP, cap);
+	if (!(cap & MCG_ELOG_P))
+		return rc;
+
+	if (!extlog_get_l1addr())
+		return rc;
+
+	rc = -EINVAL;
+	/* get L1 header to fetch necessary information */
+	l1_hdr_size = sizeof(struct extlog_l1_head);
+	r = request_mem_region(l1_dirbase, l1_hdr_size, "L1 DIR HDR");
+	if (!r) {
+		pr_warn(FW_BUG EMCA_BUG,
+			(unsigned long long)l1_dirbase,
+			(unsigned long long)l1_dirbase + l1_hdr_size);
+		goto err;
+	}
+
+	extlog_l1_hdr = acpi_os_map_memory(l1_dirbase, l1_hdr_size);
+	l1_head = (struct extlog_l1_head *)extlog_l1_hdr;
+	l1_size = l1_head->total_len;
+	l1_percpu_entry = l1_head->entries;
+	elog_base = l1_head->elog_base;
+	elog_size = l1_head->elog_len;
+	acpi_os_unmap_memory(extlog_l1_hdr, l1_hdr_size);
+	release_mem_region(l1_dirbase, l1_hdr_size);
+
+	/* remap L1 header again based on completed information */
+	r = request_mem_region(l1_dirbase, l1_size, "L1 Table");
+	if (!r) {
+		pr_warn(FW_BUG EMCA_BUG,
+			(unsigned long long)l1_dirbase,
+			(unsigned long long)l1_dirbase + l1_size);
+		goto err;
+	}
+	extlog_l1_addr = acpi_os_map_memory(l1_dirbase, l1_size);
+	l1_entry_base = (u64 *)((u8 *)extlog_l1_addr + l1_hdr_size);
+
+	/* remap elog table */
+	r = request_mem_region(elog_base, elog_size, "Elog Table");
+	if (!r) {
+		pr_warn(FW_BUG EMCA_BUG,
+			(unsigned long long)elog_base,
+			(unsigned long long)elog_base + elog_size);
+		goto err_release_l1_dir;
+	}
+	elog_addr = acpi_os_map_memory(elog_base, elog_size);
+
+	rc = -ENOMEM;
+	/* allocate buffer to save elog record */
+	elog_buf = kmalloc(ELOG_ENTRY_LEN, GFP_KERNEL);
+	if (elog_buf == NULL)
+		goto err_release_elog;
+
+	mce_register_decode_chain(&extlog_mce_dec);
+	/* enable OS to be involved to take over management from BIOS */
+	((struct extlog_l1_head *)extlog_l1_addr)->flags |= FLAG_OS_OPTIN;
+
+	return 0;
+
+err_release_elog:
+	if (elog_addr)
+		acpi_os_unmap_memory(elog_addr, elog_size);
+	release_mem_region(elog_base, elog_size);
+err_release_l1_dir:
+	if (extlog_l1_addr)
+		acpi_os_unmap_memory(extlog_l1_addr, l1_size);
+	release_mem_region(l1_dirbase, l1_size);
+err:
+	pr_warn(FW_BUG "Extended error log disabled because of problems parsing f/w tables\n");
+	return rc;
+}
+
+static void __exit extlog_exit(void)
+{
+	mce_unregister_decode_chain(&extlog_mce_dec);
+	((struct extlog_l1_head *)extlog_l1_addr)->flags &= ~FLAG_OS_OPTIN;
+	if (extlog_l1_addr)
+		acpi_os_unmap_memory(extlog_l1_addr, l1_size);
+	if (elog_addr)
+		acpi_os_unmap_memory(elog_addr, elog_size);
+	release_mem_region(elog_base, elog_size);
+	release_mem_region(l1_dirbase, l1_size);
+	kfree(elog_buf);
+}
+
+module_init(extlog_init);
+module_exit(extlog_exit);
+
+MODULE_AUTHOR("Chen, Gong <[e-mail]>");
+MODULE_DESCRIPTION("Extended MCA Error Log Driver");
+MODULE_LICENSE("GPL");

drivers/acpi/bus.c

···
 	printk("\n");
 }
 
-static acpi_status acpi_str_to_uuid(char *str, u8 *uuid)
+acpi_status acpi_str_to_uuid(char *str, u8 *uuid)
 {
 	int i;
 	static int opc_map_to_uuid[16] = {6, 4, 2, 0, 11, 9, 16, 14, 19, 21,
···
 	}
 	return AE_OK;
 }
+EXPORT_SYMBOL_GPL(acpi_str_to_uuid);
 
 acpi_status acpi_run_osc(acpi_handle handle, struct acpi_osc_context *context)
 {

include/linux/acpi.h

···
 #define OSC_INVALID_REVISION_ERROR	8
 #define OSC_CAPABILITIES_MASK_ERROR	16
 
+acpi_status acpi_str_to_uuid(char *str, u8 *uuid);
 acpi_status acpi_run_osc(acpi_handle handle, struct acpi_osc_context *context);
 
 /* platform-wide _OSC bits */