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Subject[PATCH] x86: mce: Xeon75xx specific interface to get corrected memory error information
x86: mce: Xeon75xx specific interface to get corrected memory error information

Xeon 75xx doesn't log physical addresses on corrected machine check
events in the standard architectural MSRs. Instead the address has to
be retrieved in a model specific way. This makes it impossible
to do predictive failure analysis.

Implement cpu model specific code to do this in mce-xeon75xx.c using a new hook
that is called from the generic poll code. The code retrieves
the physical address/DIMM of the last corrected error from the platform
and makes the address look like a standard architectural MCA address for
further processing.

In addition the DIMM information is retrieved and put into two new aux0/aux1
fields in struct mce. These fields are specific to a given CPU.
These fields can then be decoded by mcelog into specific DIMM information.
The latest mcelog version has support for this.

Longer term this will be likely in a different output format, but
short term that seemed like the least intrusive solution. Older
mcelog can deal with an extended record.

There's no code to print this information on a panic because this only
works for corrected errors, and corrected errors do not usually result in
panics.

The act of retrieving the DIMM/PA information can take some time, so this
code has a rate limit to avoid taking too much CPU time on a error flood.

The whole thing can be loaded as a module and has suitable
PCI-IDs so that it can be auto-loaded by a distribution.
The code also checks explicitely for the expected CPU model
number to make sure this code doesn't run anywhere else.

Signed-off-by: Andi Kleen <ak@linux.intel.com>

---
arch/x86/Kconfig | 8
arch/x86/include/asm/mce.h | 2
arch/x86/kernel/cpu/mcheck/Makefile | 1
arch/x86/kernel/cpu/mcheck/mce-internal.h | 1
arch/x86/kernel/cpu/mcheck/mce-xeon75xx.c | 427 ++++++++++++++++++++++++++++++
arch/x86/kernel/cpu/mcheck/mce.c | 12
arch/x86/kernel/e820.c | 3
7 files changed, 453 insertions(+), 1 deletion(-)

Index: linux/arch/x86/kernel/cpu/mcheck/mce.c
===================================================================
--- linux.orig/arch/x86/kernel/cpu/mcheck/mce.c
+++ linux/arch/x86/kernel/cpu/mcheck/mce.c
@@ -88,6 +88,9 @@ static DECLARE_WAIT_QUEUE_HEAD(mce_wait)
static DEFINE_PER_CPU(struct mce, mces_seen);
static int cpu_missing;

+void (*cpu_specific_poll)(struct mce *);
+EXPORT_SYMBOL_GPL(cpu_specific_poll);
+
/*
* CPU/chipset specific EDAC code can register a notifier call here to print
* MCE errors in a human-readable form.
@@ -364,6 +367,11 @@ static void mce_wrmsrl(u32 msr, u64 v)
wrmsrl(msr, v);
}

+static int under_injection(void)
+{
+ return __get_cpu_var(injectm).finished;
+}
+
/*
* Simple lockless ring to communicate PFNs from the exception handler with the
* process context work function. This is vastly simplified because there's
@@ -575,6 +583,10 @@ void machine_check_poll(enum mcp_flags f

if (!(flags & MCP_TIMESTAMP))
m.tsc = 0;
+
+ if (cpu_specific_poll && !under_injection() && !mce_dont_log_ce)
+ cpu_specific_poll(&m);
+
/*
* Don't get the IP here because it's unlikely to
* have anything to do with the actual error location.
Index: linux/arch/x86/kernel/cpu/mcheck/mce-internal.h
===================================================================
--- linux.orig/arch/x86/kernel/cpu/mcheck/mce-internal.h
+++ linux/arch/x86/kernel/cpu/mcheck/mce-internal.h
@@ -28,3 +28,4 @@ extern int mce_ser;

extern struct mce_bank *mce_banks;

+extern void (*cpu_specific_poll)(struct mce *);
Index: linux/arch/x86/include/asm/mce.h
===================================================================
--- linux.orig/arch/x86/include/asm/mce.h
+++ linux/arch/x86/include/asm/mce.h
@@ -67,6 +67,8 @@ struct mce {
__u32 socketid; /* CPU socket ID */
__u32 apicid; /* CPU initial apic ID */
__u64 mcgcap; /* MCGCAP MSR: machine check capabilities of CPU */
+ __u64 aux0; /* model specific */
+ __u64 aux1; /* model specific */
};

/*
Index: linux/arch/x86/kernel/cpu/mcheck/Makefile
===================================================================
--- linux.orig/arch/x86/kernel/cpu/mcheck/Makefile
+++ linux/arch/x86/kernel/cpu/mcheck/Makefile
@@ -2,6 +2,7 @@ obj-y = mce.o mce-severity.o

obj-$(CONFIG_X86_ANCIENT_MCE) += winchip.o p5.o
obj-$(CONFIG_X86_MCE_INTEL) += mce_intel.o
+obj-$(CONFIG_X86_MCE_XEON75XX) += mce-xeon75xx.o
obj-$(CONFIG_X86_MCE_AMD) += mce_amd.o
obj-$(CONFIG_X86_MCE_THRESHOLD) += threshold.o
obj-$(CONFIG_X86_MCE_INJECT) += mce-inject.o
Index: linux/arch/x86/kernel/cpu/mcheck/mce-xeon75xx.c
===================================================================
--- /dev/null
+++ linux/arch/x86/kernel/cpu/mcheck/mce-xeon75xx.c
@@ -0,0 +1,427 @@
+/*
+ * Xeon 7500 series specific machine check support code.
+ * Copyright 2009, 2010 Intel Corporation
+ * Author: Andi Kleen
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ *
+ * Implement Xeon 7500 series specific code to retrieve the physical address
+ * and DIMM information for corrected memory errors.
+ *
+ * Interface: mce->aux0/aux1 is mapped to a struct pfa_dimm with pad
+ * redefined to DIMM valid bits. Consumers check CPUID and bank and
+ * then interpret aux0/aux1
+ */
+
+/* #define DEBUG 1 */ /* disable for production */
+#define pr_fmt(x) "MCE: " x
+
+#include <linux/moduleparam.h>
+#include <linux/pci_ids.h>
+#include <linux/hrtimer.h>
+#include <linux/string.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/ktime.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+#include <asm/processor.h>
+#include <asm/e820.h>
+#include <asm/mce.h>
+#include <asm/io.h>
+
+#include "mce-internal.h"
+
+#define PFA_SIG "$PFA"
+#define PFA_SIG_LEN 4
+
+/* DIMM description */
+struct aux_pfa_dimm {
+ u8 fbd_channel_id;
+ u8 ddr_channel_id;
+ u8 ddr_dimm_id;
+ u8 ddr_rank_id;
+ u8 ddr_dimm_bank_id;
+ u8 ddr_dimm_row_id;
+ u8 ddr_dimm_column_id;
+ u8 valid;
+} __attribute__((packed));
+
+struct pfa_dimm {
+ u8 fbd_channel_id;
+ u8 ddr_channel_id;
+ u8 ddr_dimm_id;
+ u8 ddr_rank_id;
+ u8 ddr_dimm_bank_id;
+ u32 ddr_dimm_row_id;
+ u32 ddr_dimm_column_id;
+} __attribute__((packed));
+
+/* Memory translation table in memory. */
+struct pfa_table {
+ u8 sig[PFA_SIG_LEN]; /* Signature: '$PFA' */
+ u16 len; /* total length */
+ u16 revision; /* 0x11 */
+ u8 checksum; /* 8bit sum to zero */
+ u8 db_value; /* mailbox port command value */
+ u8 db_port; /* mailbox port */
+ /* end of header; end of checksum */
+ u8 command; /* input command */
+ u32 valid; /* valid input/output bits */
+ u16 status; /* output status */
+ u8 socket_id; /* input socket id*/
+ u8 bank_id; /* input MCE bank id */
+ u32 pad1;
+ u64 mbox_address;
+ u64 physical_addr; /* physical address */
+ struct pfa_dimm dimm[2];
+ /*
+ * topology information follows: not used for now.
+ */
+} __attribute__((packed));
+
+/* DIMM valid bits in valid: DIMM0: 8..12; DIMM1 16..20 */
+#define DIMM_VALID_BITS(val, num) (((val) >> (4 + (num) * 8)) & DIMM_VALID_ALL)
+#define DIMM_SET_VALID(val, num) ((val) << (4 + (num) * 8))
+
+enum {
+ MCE_BANK_MBOX0 = 8,
+ MCE_BANK_MBOX1 = 9,
+
+ PFA_REVISION = 0x11, /* v1.1 */
+
+ /* Status bits for valid field */
+ PFA_VALID_MA = (1 << 0),
+ PFA_VALID_SOCKETID = (1 << 1),
+ PFA_VALID_BANKID = (1 << 2),
+ PFA_VALID_PA = (1 << 3),
+
+ /* DIMM valid bits in valid */
+ /* use with DIMM_VALID_BITS/DIMM_SET_VALID for pfa->valid */
+ DIMM_VALID_FBD_CHAN = (1 << 0),
+ DIMM_VALID_DDR_CHAN = (1 << 1),
+ DIMM_VALID_DDR_DIMM = (1 << 2),
+ DIMM_VALID_DDR_RANK = (1 << 3),
+ DIMM_VALID_DIMM_BANK = (1 << 4),
+ DIMM_VALID_DIMM_ROW = (1 << 5),
+ DIMM_VALID_DIMM_COLUMN = (1 << 6),
+ DIMM_VALID_ALL = 0x7f,
+
+ PFA_DIMM_VALID_MASK = DIMM_SET_VALID(DIMM_VALID_ALL, 0)
+ | DIMM_SET_VALID(DIMM_VALID_ALL, 1),
+
+ /* Values for status field */
+ PFA_STATUS_SUCCESS = 0,
+ PFA_STATUS_SOCKET_INVALID = (1 << 1),
+ PFA_STATUS_MBOX_INVALID = (1 << 2),
+ PFA_STATUS_MA_INVALID = (1 << 3),
+ PFA_STATUS_PA_INVALID = (1 << 4),
+
+ /* Values for command field */
+ PFA_CMD_GET_MEM_CORR_ERR_PA = 0,
+ PFA_CMD_PA_TO_DIMM_ADDR = 1,
+ PFA_CMD_DIMM_TO_PA = 2,
+ PFA_CMD_GET_TOPOLOGY = 3,
+
+ /* PCI device IDs and the base register */
+ ICH_PFA_CFG = 0x8c, /* SCRATCH4 */
+ PCI_DEVICE_ID_BXB_ICH_LEGACY0 = 0x3422,
+};
+
+static struct pfa_table *pfa_table __read_mostly;
+static int memerr_max_conv_rate __read_mostly = 100;
+static int memerr_min_interval __read_mostly = 500;
+static int pfa_lost; /* for diagnosis */
+
+enum {
+ RATE_LIMIT_PERIOD = USEC_PER_SEC, /* in us; period of rate limit */
+};
+
+module_param(memerr_max_conv_rate, int, 0644);
+MODULE_PARM_DESC(memerr_max_conv_rate,
+ "Maximum number of memory error conversions each second; 0 to disable");
+module_param(memerr_min_interval, int, 0644);
+MODULE_PARM_DESC(memerr_min_interval,
+ "Minimum time delta between two memory conversions; in us; default 500");
+
+static int notest;
+static int nocsum;
+module_param(notest, int, 0);
+module_param(nocsum, int, 0);
+
+static u64 encode_dimm(struct pfa_dimm *d, u8 valid)
+{
+ union {
+ struct aux_pfa_dimm d;
+ u64 v;
+ } p;
+
+ BUILD_BUG_ON(sizeof(struct aux_pfa_dimm) != sizeof(u64));
+ p.d.fbd_channel_id = d->fbd_channel_id;
+ p.d.ddr_channel_id = d->ddr_channel_id;
+ p.d.ddr_dimm_id = d->ddr_dimm_id;
+ p.d.ddr_rank_id = d->ddr_rank_id;
+ p.d.ddr_dimm_bank_id = d->ddr_dimm_bank_id;
+ p.d.ddr_dimm_row_id = d->ddr_dimm_row_id;
+ if (p.d.ddr_dimm_row_id != d->ddr_dimm_row_id) /* truncated? */
+ valid &= ~DIMM_VALID_DIMM_ROW;
+ p.d.ddr_dimm_column_id = d->ddr_dimm_column_id;
+ if (p.d.ddr_dimm_column_id != d->ddr_dimm_column_id)
+ valid &= ~DIMM_VALID_DIMM_COLUMN;
+ p.d.valid = valid;
+ pr_debug("PFA fbd_ch %u ddr_ch %u dimm %u rank %u bank %u valid %x\n",
+ d->fbd_channel_id,
+ d->ddr_channel_id,
+ d->ddr_dimm_id,
+ d->ddr_rank_id,
+ d->ddr_dimm_bank_id,
+ valid);
+ return p.v;
+}
+
+static u8 csum(u8 *table, u16 len)
+{
+ u8 sum = 0;
+ int i;
+ for (i = 0; i < len; i++)
+ sum += *table++;
+ return sum;
+}
+
+/*
+ * Execute a command through the mailbox interface.
+ */
+static int
+pfa_command(unsigned bank, unsigned socketid, unsigned command, unsigned valid)
+{
+ pfa_table->bank_id = bank;
+ pfa_table->socket_id = socketid;
+ pfa_table->valid = valid | PFA_VALID_SOCKETID;
+ pfa_table->command = command;
+
+ outb(pfa_table->db_value, pfa_table->db_port);
+
+ mb(); /* Reread fields after they got changed */
+
+ if (pfa_table->status != PFA_STATUS_SUCCESS) {
+ pr_debug("Memory PFA command %d failed: socket:%d bank:%d status:%x\n",
+ command, socketid, bank, pfa_table->status);
+ return -pfa_table->status;
+ }
+ return 0;
+}
+
+/*
+ * Retrieve physical address and DIMMs.
+ */
+static int translate_memory_error(struct mce *m)
+{
+ struct pfa_table *pfa = pfa_table;
+ u64 status;
+ int ret;
+ u32 valid;
+ int cpu = smp_processor_id();
+
+ /* Make sure our structures match the specification */
+ BUILD_BUG_ON(offsetof(struct pfa_table, physical_addr) != 0x20);
+ BUILD_BUG_ON(offsetof(struct pfa_table, status) != 0x10);
+ BUILD_BUG_ON(offsetof(struct pfa_table, physical_addr) != 0x20);
+ BUILD_BUG_ON(offsetof(struct pfa_table, dimm[1].ddr_dimm_column_id) !=
+ 0x3e);
+
+ /* Ask for PA/DIMMs of last error */
+ if (pfa_command(m->bank, m->socketid,
+ PFA_CMD_GET_MEM_CORR_ERR_PA, PFA_VALID_BANKID) < 0)
+ return -1;
+
+ /*
+ * Recheck machine check bank. If the overflow bit was set
+ * there was a race. Don't use the information in this case.
+ */
+ rdmsrl(MSR_IA32_MCx_STATUS(m->bank), status);
+ if (status & MCI_STATUS_OVER) {
+ pr_debug("%d: overflow race on bank %d\n", cpu, m->bank);
+ return -1;
+ }
+
+ ret = -1;
+ valid = pfa->valid;
+ if (valid & PFA_VALID_PA) {
+ m->status |= MCI_STATUS_ADDRV;
+ m->addr = pfa_table->physical_addr;
+ pr_debug("%d: got physical address %llx valid %x\n",
+ cpu, m->addr, valid);
+ ret = 0;
+ }
+
+ /* When DIMM information was supplied pass it out */
+ if (valid & PFA_DIMM_VALID_MASK) {
+ m->aux0 = encode_dimm(&pfa->dimm[0], DIMM_VALID_BITS(valid, 0));
+ m->aux1 = encode_dimm(&pfa->dimm[1], DIMM_VALID_BITS(valid, 1));
+ ret = 0;
+ }
+
+ return ret;
+}
+
+/*
+ * Xeon 75xx specific mce poll method to retrieve the physical address
+ * and DIMM information.
+ */
+static void xeon75xx_mce_poll(struct mce *m)
+{
+ static DEFINE_SPINLOCK(convert_lock); /* Protect table and static */
+ static unsigned long cperm;
+ static ktime_t last, last_int;
+ unsigned long flags;
+ ktime_t now;
+ s64 delta;
+
+ /* Memory error? */
+ if (m->bank != MCE_BANK_MBOX0 && m->bank != MCE_BANK_MBOX1)
+ return;
+ if (m->status & MCI_STATUS_OVER)
+ return;
+ if (memerr_max_conv_rate == 0)
+ return;
+
+ spin_lock_irqsave(&convert_lock, flags);
+ /*
+ * Rate limit conversions. The conversion takes some time,
+ * but it's not good to use all the CPU time during a error
+ * flood.
+ * Enforce maximum number per second and minimum interval.
+ * The ktime call should use TSC on this machine and be fast.
+ */
+ now = ktime_get();
+ delta = ktime_us_delta(now, last);
+ if (delta >= RATE_LIMIT_PERIOD) {
+ cperm = 0;
+ last = now;
+ }
+ if (ktime_us_delta(now, last_int) >= memerr_min_interval &&
+ ++cperm <= memerr_max_conv_rate) {
+ if (translate_memory_error(m) < 0) {
+ /* On error stop converting for the next second */
+ cperm = memerr_max_conv_rate;
+ pr_debug("PFA translation failed\n");
+ }
+ } else
+ pfa_lost++;
+ last_int = now;
+ spin_unlock_irqrestore(&convert_lock, flags);
+}
+
+static struct pci_device_id bxb_mce_pciids[] = {
+ { PCI_VDEVICE(INTEL, PCI_DEVICE_ID_BXB_ICH_LEGACY0) },
+ {}
+};
+
+static int __init xeon75xx_mce_init(void)
+{
+ u32 addr = 0;
+ struct pci_dev *dev;
+
+ if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL ||
+ boot_cpu_data.x86 != 6 ||
+ boot_cpu_data.x86_model != 0x2e)
+ return -ENODEV;
+
+ /*
+ * Get table address from register in IOH.
+ * This just looks up the device, because we don't want to "own" it.
+ */
+ dev = NULL;
+ while ((dev = pci_get_device(PCI_VENDOR_ID_INTEL, PCI_ANY_ID, dev))
+ != NULL) {
+ if (!pci_match_id(bxb_mce_pciids, dev))
+ continue;
+ pci_read_config_dword(dev, ICH_PFA_CFG, &addr);
+ if (addr)
+ break;
+ }
+ pci_dev_put(dev);
+ if (!addr)
+ return -ENODEV;
+
+ if (!e820_all_mapped(addr, addr + PAGE_SIZE, E820_RESERVED)) {
+ pr_info("PFA table at %x not e820 reserved\n", addr);
+ return -ENODEV;
+ }
+
+ pfa_table = (__force struct pfa_table *)ioremap_cache(addr, PAGE_SIZE);
+ if (!pfa_table) {
+ pr_err("Cannot map PFA table at %x\n", addr);
+ return -EIO;
+ }
+
+ if (memcmp(&pfa_table->sig, PFA_SIG, PFA_SIG_LEN) ||
+ pfa_table->len < sizeof(struct pfa_table) ||
+ /* assume newer versions are compatible */
+ pfa_table->revision < PFA_REVISION) {
+ pr_info("PFA table at %x invalid\n", addr);
+ goto error_unmap;
+ }
+
+ if (!nocsum && csum((u8 *)pfa_table,
+ offsetof(struct pfa_table, command))) {
+ pr_info("PFA table at %x length %u has invalid checksum\n",
+ addr, pfa_table->len);
+ goto error_unmap;
+ }
+
+ /* Not strictly needed today */
+ if (pfa_table->len > PAGE_SIZE) {
+ unsigned len = roundup(pfa_table->len, PAGE_SIZE);
+ iounmap(pfa_table);
+ pfa_table = (__force void *)ioremap_cache(addr, len);
+ if (!pfa_table) {
+ pr_err("Cannot remap %u bytes PFA table at %x\n",
+ len, addr);
+ return -EIO;
+ }
+ }
+
+ if (!notest) {
+ int status = pfa_command(0, 0, PFA_CMD_GET_TOPOLOGY, 0);
+ if (status < 0) {
+ pr_err("Test of PFA table failed: %x\n", -status);
+ goto error_unmap;
+ }
+ }
+
+ pr_info("Found Xeon75xx PFA memory error translation table at %x\n",
+ addr);
+ mb();
+ cpu_specific_poll = xeon75xx_mce_poll;
+ return 0;
+
+error_unmap:
+ iounmap(pfa_table);
+ return -ENODEV;
+}
+
+MODULE_DEVICE_TABLE(pci, bxb_mce_pciids);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Andi Kleen");
+MODULE_DESCRIPTION("Intel Xeon 75xx specific DIMM error reporting");
+
+#ifdef CONFIG_MODULE
+static void __exit xeon75xx_mce_exit(void)
+{
+ cpu_specific_poll = NULL;
+ wmb();
+ /* Wait for all machine checks to finish before really unloading */
+ synchronize_rcu();
+ iounmap(pfa_table);
+}
+
+module_init(xeon75xx_mce_init);
+module_exit(xeon75xx_mce_exit);
+#else
+/* When built-in run as soon as the PCI subsystem is up */
+fs_initcall(xeon75xx_mce_init);
+#endif
Index: linux/arch/x86/kernel/e820.c
===================================================================
--- linux.orig/arch/x86/kernel/e820.c
+++ linux/arch/x86/kernel/e820.c
@@ -79,7 +79,7 @@ EXPORT_SYMBOL_GPL(e820_any_mapped);
* Note: this function only works correct if the e820 table is sorted and
* not-overlapping, which is the case
*/
-int __init e820_all_mapped(u64 start, u64 end, unsigned type)
+int e820_all_mapped(u64 start, u64 end, unsigned type)
{
int i;

@@ -106,6 +106,7 @@ int __init e820_all_mapped(u64 start, u6
}
return 0;
}
+EXPORT_SYMBOL_GPL(e820_all_mapped);

/*
* Add a memory region to the kernel e820 map.
Index: linux/arch/x86/Kconfig
===================================================================
--- linux.orig/arch/x86/Kconfig
+++ linux/arch/x86/Kconfig
@@ -831,6 +831,14 @@ config X86_MCE_INTEL
Additional support for intel specific MCE features such as
the thermal monitor.

+config X86_MCE_XEON75XX
+ tristate "Intel Xeon 7500 series corrected memory error driver"
+ depends on X86_MCE_INTEL
+ ---help---
+ Add support for a Intel Xeon 7500 series specific memory error driver.
+ This allows to report the DIMM and physical address on a corrected
+ memory error machine check event.
+
config X86_MCE_AMD
def_bool y
prompt "AMD MCE features"

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