linux_dsm_epyc7002/arch/powerpc/kernel/eeh.c
Gavin Shan 66f9af83e5 powerpc/eeh: Disable EEH on reboot
We possiblly detect EEH errors during reboot, particularly in kexec
path, but it's impossible for device drivers and EEH core to handle
or recover them properly.

The patch registers one reboot notifier for EEH and disable EEH
subsystem during reboot. That means the EEH errors is going to be
cleared by hardware reset or second kernel during early stage of
PCI probe.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-02-17 11:19:39 +11:00

1112 lines
31 KiB
C

/*
* Copyright IBM Corporation 2001, 2005, 2006
* Copyright Dave Engebretsen & Todd Inglett 2001
* Copyright Linas Vepstas 2005, 2006
* Copyright 2001-2012 IBM Corporation.
*
* 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; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Please address comments and feedback to Linas Vepstas <linas@austin.ibm.com>
*/
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/pci.h>
#include <linux/proc_fs.h>
#include <linux/rbtree.h>
#include <linux/reboot.h>
#include <linux/seq_file.h>
#include <linux/spinlock.h>
#include <linux/export.h>
#include <linux/of.h>
#include <linux/atomic.h>
#include <asm/eeh.h>
#include <asm/eeh_event.h>
#include <asm/io.h>
#include <asm/machdep.h>
#include <asm/ppc-pci.h>
#include <asm/rtas.h>
/** Overview:
* EEH, or "Extended Error Handling" is a PCI bridge technology for
* dealing with PCI bus errors that can't be dealt with within the
* usual PCI framework, except by check-stopping the CPU. Systems
* that are designed for high-availability/reliability cannot afford
* to crash due to a "mere" PCI error, thus the need for EEH.
* An EEH-capable bridge operates by converting a detected error
* into a "slot freeze", taking the PCI adapter off-line, making
* the slot behave, from the OS'es point of view, as if the slot
* were "empty": all reads return 0xff's and all writes are silently
* ignored. EEH slot isolation events can be triggered by parity
* errors on the address or data busses (e.g. during posted writes),
* which in turn might be caused by low voltage on the bus, dust,
* vibration, humidity, radioactivity or plain-old failed hardware.
*
* Note, however, that one of the leading causes of EEH slot
* freeze events are buggy device drivers, buggy device microcode,
* or buggy device hardware. This is because any attempt by the
* device to bus-master data to a memory address that is not
* assigned to the device will trigger a slot freeze. (The idea
* is to prevent devices-gone-wild from corrupting system memory).
* Buggy hardware/drivers will have a miserable time co-existing
* with EEH.
*
* Ideally, a PCI device driver, when suspecting that an isolation
* event has occurred (e.g. by reading 0xff's), will then ask EEH
* whether this is the case, and then take appropriate steps to
* reset the PCI slot, the PCI device, and then resume operations.
* However, until that day, the checking is done here, with the
* eeh_check_failure() routine embedded in the MMIO macros. If
* the slot is found to be isolated, an "EEH Event" is synthesized
* and sent out for processing.
*/
/* If a device driver keeps reading an MMIO register in an interrupt
* handler after a slot isolation event, it might be broken.
* This sets the threshold for how many read attempts we allow
* before printing an error message.
*/
#define EEH_MAX_FAILS 2100000
/* Time to wait for a PCI slot to report status, in milliseconds */
#define PCI_BUS_RESET_WAIT_MSEC (5*60*1000)
/* Platform dependent EEH operations */
struct eeh_ops *eeh_ops = NULL;
bool eeh_subsystem_enabled = false;
EXPORT_SYMBOL(eeh_subsystem_enabled);
/*
* EEH probe mode support. The intention is to support multiple
* platforms for EEH. Some platforms like pSeries do PCI emunation
* based on device tree. However, other platforms like powernv probe
* PCI devices from hardware. The flag is used to distinguish that.
* In addition, struct eeh_ops::probe would be invoked for particular
* OF node or PCI device so that the corresponding PE would be created
* there.
*/
int eeh_probe_mode;
/* Lock to avoid races due to multiple reports of an error */
DEFINE_RAW_SPINLOCK(confirm_error_lock);
/* Buffer for reporting pci register dumps. Its here in BSS, and
* not dynamically alloced, so that it ends up in RMO where RTAS
* can access it.
*/
#define EEH_PCI_REGS_LOG_LEN 4096
static unsigned char pci_regs_buf[EEH_PCI_REGS_LOG_LEN];
/*
* The struct is used to maintain the EEH global statistic
* information. Besides, the EEH global statistics will be
* exported to user space through procfs
*/
struct eeh_stats {
u64 no_device; /* PCI device not found */
u64 no_dn; /* OF node not found */
u64 no_cfg_addr; /* Config address not found */
u64 ignored_check; /* EEH check skipped */
u64 total_mmio_ffs; /* Total EEH checks */
u64 false_positives; /* Unnecessary EEH checks */
u64 slot_resets; /* PE reset */
};
static struct eeh_stats eeh_stats;
#define IS_BRIDGE(class_code) (((class_code)<<16) == PCI_BASE_CLASS_BRIDGE)
/**
* eeh_gather_pci_data - Copy assorted PCI config space registers to buff
* @edev: device to report data for
* @buf: point to buffer in which to log
* @len: amount of room in buffer
*
* This routine captures assorted PCI configuration space data,
* and puts them into a buffer for RTAS error logging.
*/
static size_t eeh_gather_pci_data(struct eeh_dev *edev, char * buf, size_t len)
{
struct device_node *dn = eeh_dev_to_of_node(edev);
struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
u32 cfg;
int cap, i;
int n = 0;
n += scnprintf(buf+n, len-n, "%s\n", dn->full_name);
printk(KERN_WARNING "EEH: of node=%s\n", dn->full_name);
eeh_ops->read_config(dn, PCI_VENDOR_ID, 4, &cfg);
n += scnprintf(buf+n, len-n, "dev/vend:%08x\n", cfg);
printk(KERN_WARNING "EEH: PCI device/vendor: %08x\n", cfg);
eeh_ops->read_config(dn, PCI_COMMAND, 4, &cfg);
n += scnprintf(buf+n, len-n, "cmd/stat:%x\n", cfg);
printk(KERN_WARNING "EEH: PCI cmd/status register: %08x\n", cfg);
if (!dev) {
printk(KERN_WARNING "EEH: no PCI device for this of node\n");
return n;
}
/* Gather bridge-specific registers */
if (dev->class >> 16 == PCI_BASE_CLASS_BRIDGE) {
eeh_ops->read_config(dn, PCI_SEC_STATUS, 2, &cfg);
n += scnprintf(buf+n, len-n, "sec stat:%x\n", cfg);
printk(KERN_WARNING "EEH: Bridge secondary status: %04x\n", cfg);
eeh_ops->read_config(dn, PCI_BRIDGE_CONTROL, 2, &cfg);
n += scnprintf(buf+n, len-n, "brdg ctl:%x\n", cfg);
printk(KERN_WARNING "EEH: Bridge control: %04x\n", cfg);
}
/* Dump out the PCI-X command and status regs */
cap = pci_find_capability(dev, PCI_CAP_ID_PCIX);
if (cap) {
eeh_ops->read_config(dn, cap, 4, &cfg);
n += scnprintf(buf+n, len-n, "pcix-cmd:%x\n", cfg);
printk(KERN_WARNING "EEH: PCI-X cmd: %08x\n", cfg);
eeh_ops->read_config(dn, cap+4, 4, &cfg);
n += scnprintf(buf+n, len-n, "pcix-stat:%x\n", cfg);
printk(KERN_WARNING "EEH: PCI-X status: %08x\n", cfg);
}
/* If PCI-E capable, dump PCI-E cap 10, and the AER */
if (pci_is_pcie(dev)) {
n += scnprintf(buf+n, len-n, "pci-e cap10:\n");
printk(KERN_WARNING
"EEH: PCI-E capabilities and status follow:\n");
for (i=0; i<=8; i++) {
eeh_ops->read_config(dn, dev->pcie_cap+4*i, 4, &cfg);
n += scnprintf(buf+n, len-n, "%02x:%x\n", 4*i, cfg);
printk(KERN_WARNING "EEH: PCI-E %02x: %08x\n", i, cfg);
}
cap = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
if (cap) {
n += scnprintf(buf+n, len-n, "pci-e AER:\n");
printk(KERN_WARNING
"EEH: PCI-E AER capability register set follows:\n");
for (i=0; i<14; i++) {
eeh_ops->read_config(dn, cap+4*i, 4, &cfg);
n += scnprintf(buf+n, len-n, "%02x:%x\n", 4*i, cfg);
printk(KERN_WARNING "EEH: PCI-E AER %02x: %08x\n", i, cfg);
}
}
}
return n;
}
/**
* eeh_slot_error_detail - Generate combined log including driver log and error log
* @pe: EEH PE
* @severity: temporary or permanent error log
*
* This routine should be called to generate the combined log, which
* is comprised of driver log and error log. The driver log is figured
* out from the config space of the corresponding PCI device, while
* the error log is fetched through platform dependent function call.
*/
void eeh_slot_error_detail(struct eeh_pe *pe, int severity)
{
size_t loglen = 0;
struct eeh_dev *edev, *tmp;
bool valid_cfg_log = true;
/*
* When the PHB is fenced or dead, it's pointless to collect
* the data from PCI config space because it should return
* 0xFF's. For ER, we still retrieve the data from the PCI
* config space.
*/
if (eeh_probe_mode_dev() &&
(pe->type & EEH_PE_PHB) &&
(pe->state & (EEH_PE_ISOLATED | EEH_PE_PHB_DEAD)))
valid_cfg_log = false;
if (valid_cfg_log) {
eeh_pci_enable(pe, EEH_OPT_THAW_MMIO);
eeh_ops->configure_bridge(pe);
eeh_pe_restore_bars(pe);
pci_regs_buf[0] = 0;
eeh_pe_for_each_dev(pe, edev, tmp) {
loglen += eeh_gather_pci_data(edev, pci_regs_buf + loglen,
EEH_PCI_REGS_LOG_LEN - loglen);
}
}
eeh_ops->get_log(pe, severity, pci_regs_buf, loglen);
}
/**
* eeh_token_to_phys - Convert EEH address token to phys address
* @token: I/O token, should be address in the form 0xA....
*
* This routine should be called to convert virtual I/O address
* to physical one.
*/
static inline unsigned long eeh_token_to_phys(unsigned long token)
{
pte_t *ptep;
unsigned long pa;
int hugepage_shift;
/*
* We won't find hugepages here, iomem
*/
ptep = find_linux_pte_or_hugepte(init_mm.pgd, token, &hugepage_shift);
if (!ptep)
return token;
WARN_ON(hugepage_shift);
pa = pte_pfn(*ptep) << PAGE_SHIFT;
return pa | (token & (PAGE_SIZE-1));
}
/*
* On PowerNV platform, we might already have fenced PHB there.
* For that case, it's meaningless to recover frozen PE. Intead,
* We have to handle fenced PHB firstly.
*/
static int eeh_phb_check_failure(struct eeh_pe *pe)
{
struct eeh_pe *phb_pe;
unsigned long flags;
int ret;
if (!eeh_probe_mode_dev())
return -EPERM;
/* Find the PHB PE */
phb_pe = eeh_phb_pe_get(pe->phb);
if (!phb_pe) {
pr_warning("%s Can't find PE for PHB#%d\n",
__func__, pe->phb->global_number);
return -EEXIST;
}
/* If the PHB has been in problematic state */
eeh_serialize_lock(&flags);
if (phb_pe->state & (EEH_PE_ISOLATED | EEH_PE_PHB_DEAD)) {
ret = 0;
goto out;
}
/* Check PHB state */
ret = eeh_ops->get_state(phb_pe, NULL);
if ((ret < 0) ||
(ret == EEH_STATE_NOT_SUPPORT) ||
(ret & (EEH_STATE_MMIO_ACTIVE | EEH_STATE_DMA_ACTIVE)) ==
(EEH_STATE_MMIO_ACTIVE | EEH_STATE_DMA_ACTIVE)) {
ret = 0;
goto out;
}
/* Isolate the PHB and send event */
eeh_pe_state_mark(phb_pe, EEH_PE_ISOLATED);
eeh_serialize_unlock(flags);
pr_err("EEH: PHB#%x failure detected\n",
phb_pe->phb->global_number);
dump_stack();
eeh_send_failure_event(phb_pe);
return 1;
out:
eeh_serialize_unlock(flags);
return ret;
}
/**
* eeh_dev_check_failure - Check if all 1's data is due to EEH slot freeze
* @edev: eeh device
*
* Check for an EEH failure for the given device node. Call this
* routine if the result of a read was all 0xff's and you want to
* find out if this is due to an EEH slot freeze. This routine
* will query firmware for the EEH status.
*
* Returns 0 if there has not been an EEH error; otherwise returns
* a non-zero value and queues up a slot isolation event notification.
*
* It is safe to call this routine in an interrupt context.
*/
int eeh_dev_check_failure(struct eeh_dev *edev)
{
int ret;
unsigned long flags;
struct device_node *dn;
struct pci_dev *dev;
struct eeh_pe *pe;
int rc = 0;
const char *location;
eeh_stats.total_mmio_ffs++;
if (!eeh_enabled())
return 0;
if (!edev) {
eeh_stats.no_dn++;
return 0;
}
dn = eeh_dev_to_of_node(edev);
dev = eeh_dev_to_pci_dev(edev);
pe = edev->pe;
/* Access to IO BARs might get this far and still not want checking. */
if (!pe) {
eeh_stats.ignored_check++;
pr_debug("EEH: Ignored check for %s %s\n",
eeh_pci_name(dev), dn->full_name);
return 0;
}
if (!pe->addr && !pe->config_addr) {
eeh_stats.no_cfg_addr++;
return 0;
}
/*
* On PowerNV platform, we might already have fenced PHB
* there and we need take care of that firstly.
*/
ret = eeh_phb_check_failure(pe);
if (ret > 0)
return ret;
/* If we already have a pending isolation event for this
* slot, we know it's bad already, we don't need to check.
* Do this checking under a lock; as multiple PCI devices
* in one slot might report errors simultaneously, and we
* only want one error recovery routine running.
*/
eeh_serialize_lock(&flags);
rc = 1;
if (pe->state & EEH_PE_ISOLATED) {
pe->check_count++;
if (pe->check_count % EEH_MAX_FAILS == 0) {
location = of_get_property(dn, "ibm,loc-code", NULL);
printk(KERN_ERR "EEH: %d reads ignored for recovering device at "
"location=%s driver=%s pci addr=%s\n",
pe->check_count, location,
eeh_driver_name(dev), eeh_pci_name(dev));
printk(KERN_ERR "EEH: Might be infinite loop in %s driver\n",
eeh_driver_name(dev));
dump_stack();
}
goto dn_unlock;
}
/*
* Now test for an EEH failure. This is VERY expensive.
* Note that the eeh_config_addr may be a parent device
* in the case of a device behind a bridge, or it may be
* function zero of a multi-function device.
* In any case they must share a common PHB.
*/
ret = eeh_ops->get_state(pe, NULL);
/* Note that config-io to empty slots may fail;
* they are empty when they don't have children.
* We will punt with the following conditions: Failure to get
* PE's state, EEH not support and Permanently unavailable
* state, PE is in good state.
*/
if ((ret < 0) ||
(ret == EEH_STATE_NOT_SUPPORT) ||
(ret & (EEH_STATE_MMIO_ACTIVE | EEH_STATE_DMA_ACTIVE)) ==
(EEH_STATE_MMIO_ACTIVE | EEH_STATE_DMA_ACTIVE)) {
eeh_stats.false_positives++;
pe->false_positives++;
rc = 0;
goto dn_unlock;
}
eeh_stats.slot_resets++;
/* Avoid repeated reports of this failure, including problems
* with other functions on this device, and functions under
* bridges.
*/
eeh_pe_state_mark(pe, EEH_PE_ISOLATED);
eeh_serialize_unlock(flags);
/* Most EEH events are due to device driver bugs. Having
* a stack trace will help the device-driver authors figure
* out what happened. So print that out.
*/
pr_err("EEH: Frozen PE#%x detected on PHB#%x\n",
pe->addr, pe->phb->global_number);
dump_stack();
eeh_send_failure_event(pe);
return 1;
dn_unlock:
eeh_serialize_unlock(flags);
return rc;
}
EXPORT_SYMBOL_GPL(eeh_dev_check_failure);
/**
* eeh_check_failure - Check if all 1's data is due to EEH slot freeze
* @token: I/O token, should be address in the form 0xA....
* @val: value, should be all 1's (XXX why do we need this arg??)
*
* Check for an EEH failure at the given token address. Call this
* routine if the result of a read was all 0xff's and you want to
* find out if this is due to an EEH slot freeze event. This routine
* will query firmware for the EEH status.
*
* Note this routine is safe to call in an interrupt context.
*/
unsigned long eeh_check_failure(const volatile void __iomem *token, unsigned long val)
{
unsigned long addr;
struct eeh_dev *edev;
/* Finding the phys addr + pci device; this is pretty quick. */
addr = eeh_token_to_phys((unsigned long __force) token);
edev = eeh_addr_cache_get_dev(addr);
if (!edev) {
eeh_stats.no_device++;
return val;
}
eeh_dev_check_failure(edev);
return val;
}
EXPORT_SYMBOL(eeh_check_failure);
/**
* eeh_pci_enable - Enable MMIO or DMA transfers for this slot
* @pe: EEH PE
*
* This routine should be called to reenable frozen MMIO or DMA
* so that it would work correctly again. It's useful while doing
* recovery or log collection on the indicated device.
*/
int eeh_pci_enable(struct eeh_pe *pe, int function)
{
int rc;
rc = eeh_ops->set_option(pe, function);
if (rc)
pr_warning("%s: Unexpected state change %d on PHB#%d-PE#%x, err=%d\n",
__func__, function, pe->phb->global_number, pe->addr, rc);
rc = eeh_ops->wait_state(pe, PCI_BUS_RESET_WAIT_MSEC);
if (rc > 0 && (rc & EEH_STATE_MMIO_ENABLED) &&
(function == EEH_OPT_THAW_MMIO))
return 0;
return rc;
}
/**
* pcibios_set_pcie_slot_reset - Set PCI-E reset state
* @dev: pci device struct
* @state: reset state to enter
*
* Return value:
* 0 if success
*/
int pcibios_set_pcie_reset_state(struct pci_dev *dev, enum pcie_reset_state state)
{
struct eeh_dev *edev = pci_dev_to_eeh_dev(dev);
struct eeh_pe *pe = edev->pe;
if (!pe) {
pr_err("%s: No PE found on PCI device %s\n",
__func__, pci_name(dev));
return -EINVAL;
}
switch (state) {
case pcie_deassert_reset:
eeh_ops->reset(pe, EEH_RESET_DEACTIVATE);
break;
case pcie_hot_reset:
eeh_ops->reset(pe, EEH_RESET_HOT);
break;
case pcie_warm_reset:
eeh_ops->reset(pe, EEH_RESET_FUNDAMENTAL);
break;
default:
return -EINVAL;
};
return 0;
}
/**
* eeh_set_pe_freset - Check the required reset for the indicated device
* @data: EEH device
* @flag: return value
*
* Each device might have its preferred reset type: fundamental or
* hot reset. The routine is used to collected the information for
* the indicated device and its children so that the bunch of the
* devices could be reset properly.
*/
static void *eeh_set_dev_freset(void *data, void *flag)
{
struct pci_dev *dev;
unsigned int *freset = (unsigned int *)flag;
struct eeh_dev *edev = (struct eeh_dev *)data;
dev = eeh_dev_to_pci_dev(edev);
if (dev)
*freset |= dev->needs_freset;
return NULL;
}
/**
* eeh_reset_pe_once - Assert the pci #RST line for 1/4 second
* @pe: EEH PE
*
* Assert the PCI #RST line for 1/4 second.
*/
static void eeh_reset_pe_once(struct eeh_pe *pe)
{
unsigned int freset = 0;
/* Determine type of EEH reset required for
* Partitionable Endpoint, a hot-reset (1)
* or a fundamental reset (3).
* A fundamental reset required by any device under
* Partitionable Endpoint trumps hot-reset.
*/
eeh_pe_dev_traverse(pe, eeh_set_dev_freset, &freset);
if (freset)
eeh_ops->reset(pe, EEH_RESET_FUNDAMENTAL);
else
eeh_ops->reset(pe, EEH_RESET_HOT);
/* The PCI bus requires that the reset be held high for at least
* a 100 milliseconds. We wait a bit longer 'just in case'.
*/
#define PCI_BUS_RST_HOLD_TIME_MSEC 250
msleep(PCI_BUS_RST_HOLD_TIME_MSEC);
/* We might get hit with another EEH freeze as soon as the
* pci slot reset line is dropped. Make sure we don't miss
* these, and clear the flag now.
*/
eeh_pe_state_clear(pe, EEH_PE_ISOLATED);
eeh_ops->reset(pe, EEH_RESET_DEACTIVATE);
/* After a PCI slot has been reset, the PCI Express spec requires
* a 1.5 second idle time for the bus to stabilize, before starting
* up traffic.
*/
#define PCI_BUS_SETTLE_TIME_MSEC 1800
msleep(PCI_BUS_SETTLE_TIME_MSEC);
}
/**
* eeh_reset_pe - Reset the indicated PE
* @pe: EEH PE
*
* This routine should be called to reset indicated device, including
* PE. A PE might include multiple PCI devices and sometimes PCI bridges
* might be involved as well.
*/
int eeh_reset_pe(struct eeh_pe *pe)
{
int flags = (EEH_STATE_MMIO_ACTIVE | EEH_STATE_DMA_ACTIVE);
int i, rc;
/* Take three shots at resetting the bus */
for (i=0; i<3; i++) {
eeh_reset_pe_once(pe);
rc = eeh_ops->wait_state(pe, PCI_BUS_RESET_WAIT_MSEC);
if ((rc & flags) == flags)
return 0;
if (rc < 0) {
pr_err("%s: Unrecoverable slot failure on PHB#%d-PE#%x",
__func__, pe->phb->global_number, pe->addr);
return -1;
}
pr_err("EEH: bus reset %d failed on PHB#%d-PE#%x, rc=%d\n",
i+1, pe->phb->global_number, pe->addr, rc);
}
return -1;
}
/**
* eeh_save_bars - Save device bars
* @edev: PCI device associated EEH device
*
* Save the values of the device bars. Unlike the restore
* routine, this routine is *not* recursive. This is because
* PCI devices are added individually; but, for the restore,
* an entire slot is reset at a time.
*/
void eeh_save_bars(struct eeh_dev *edev)
{
int i;
struct device_node *dn;
if (!edev)
return;
dn = eeh_dev_to_of_node(edev);
for (i = 0; i < 16; i++)
eeh_ops->read_config(dn, i * 4, 4, &edev->config_space[i]);
/*
* For PCI bridges including root port, we need enable bus
* master explicitly. Otherwise, it can't fetch IODA table
* entries correctly. So we cache the bit in advance so that
* we can restore it after reset, either PHB range or PE range.
*/
if (edev->mode & EEH_DEV_BRIDGE)
edev->config_space[1] |= PCI_COMMAND_MASTER;
}
/**
* eeh_ops_register - Register platform dependent EEH operations
* @ops: platform dependent EEH operations
*
* Register the platform dependent EEH operation callback
* functions. The platform should call this function before
* any other EEH operations.
*/
int __init eeh_ops_register(struct eeh_ops *ops)
{
if (!ops->name) {
pr_warning("%s: Invalid EEH ops name for %p\n",
__func__, ops);
return -EINVAL;
}
if (eeh_ops && eeh_ops != ops) {
pr_warning("%s: EEH ops of platform %s already existing (%s)\n",
__func__, eeh_ops->name, ops->name);
return -EEXIST;
}
eeh_ops = ops;
return 0;
}
/**
* eeh_ops_unregister - Unreigster platform dependent EEH operations
* @name: name of EEH platform operations
*
* Unregister the platform dependent EEH operation callback
* functions.
*/
int __exit eeh_ops_unregister(const char *name)
{
if (!name || !strlen(name)) {
pr_warning("%s: Invalid EEH ops name\n",
__func__);
return -EINVAL;
}
if (eeh_ops && !strcmp(eeh_ops->name, name)) {
eeh_ops = NULL;
return 0;
}
return -EEXIST;
}
static int eeh_reboot_notifier(struct notifier_block *nb,
unsigned long action, void *unused)
{
eeh_set_enable(false);
return NOTIFY_DONE;
}
static struct notifier_block eeh_reboot_nb = {
.notifier_call = eeh_reboot_notifier,
};
/**
* eeh_init - EEH initialization
*
* Initialize EEH by trying to enable it for all of the adapters in the system.
* As a side effect we can determine here if eeh is supported at all.
* Note that we leave EEH on so failed config cycles won't cause a machine
* check. If a user turns off EEH for a particular adapter they are really
* telling Linux to ignore errors. Some hardware (e.g. POWER5) won't
* grant access to a slot if EEH isn't enabled, and so we always enable
* EEH for all slots/all devices.
*
* The eeh-force-off option disables EEH checking globally, for all slots.
* Even if force-off is set, the EEH hardware is still enabled, so that
* newer systems can boot.
*/
int eeh_init(void)
{
struct pci_controller *hose, *tmp;
struct device_node *phb;
static int cnt = 0;
int ret = 0;
/*
* We have to delay the initialization on PowerNV after
* the PCI hierarchy tree has been built because the PEs
* are figured out based on PCI devices instead of device
* tree nodes
*/
if (machine_is(powernv) && cnt++ <= 0)
return ret;
/* Register reboot notifier */
ret = register_reboot_notifier(&eeh_reboot_nb);
if (ret) {
pr_warn("%s: Failed to register notifier (%d)\n",
__func__, ret);
return ret;
}
/* call platform initialization function */
if (!eeh_ops) {
pr_warning("%s: Platform EEH operation not found\n",
__func__);
return -EEXIST;
} else if ((ret = eeh_ops->init())) {
pr_warning("%s: Failed to call platform init function (%d)\n",
__func__, ret);
return ret;
}
/* Initialize EEH event */
ret = eeh_event_init();
if (ret)
return ret;
/* Enable EEH for all adapters */
if (eeh_probe_mode_devtree()) {
list_for_each_entry_safe(hose, tmp,
&hose_list, list_node) {
phb = hose->dn;
traverse_pci_devices(phb, eeh_ops->of_probe, NULL);
}
} else if (eeh_probe_mode_dev()) {
list_for_each_entry_safe(hose, tmp,
&hose_list, list_node)
pci_walk_bus(hose->bus, eeh_ops->dev_probe, NULL);
} else {
pr_warning("%s: Invalid probe mode %d\n",
__func__, eeh_probe_mode);
return -EINVAL;
}
/*
* Call platform post-initialization. Actually, It's good chance
* to inform platform that EEH is ready to supply service if the
* I/O cache stuff has been built up.
*/
if (eeh_ops->post_init) {
ret = eeh_ops->post_init();
if (ret)
return ret;
}
if (eeh_enabled())
pr_info("EEH: PCI Enhanced I/O Error Handling Enabled\n");
else
pr_warning("EEH: No capable adapters found\n");
return ret;
}
core_initcall_sync(eeh_init);
/**
* eeh_add_device_early - Enable EEH for the indicated device_node
* @dn: device node for which to set up EEH
*
* This routine must be used to perform EEH initialization for PCI
* devices that were added after system boot (e.g. hotplug, dlpar).
* This routine must be called before any i/o is performed to the
* adapter (inluding any config-space i/o).
* Whether this actually enables EEH or not for this device depends
* on the CEC architecture, type of the device, on earlier boot
* command-line arguments & etc.
*/
void eeh_add_device_early(struct device_node *dn)
{
struct pci_controller *phb;
/*
* If we're doing EEH probe based on PCI device, we
* would delay the probe until late stage because
* the PCI device isn't available this moment.
*/
if (!eeh_probe_mode_devtree())
return;
if (!of_node_to_eeh_dev(dn))
return;
phb = of_node_to_eeh_dev(dn)->phb;
/* USB Bus children of PCI devices will not have BUID's */
if (NULL == phb || 0 == phb->buid)
return;
eeh_ops->of_probe(dn, NULL);
}
/**
* eeh_add_device_tree_early - Enable EEH for the indicated device
* @dn: device node
*
* This routine must be used to perform EEH initialization for the
* indicated PCI device that was added after system boot (e.g.
* hotplug, dlpar).
*/
void eeh_add_device_tree_early(struct device_node *dn)
{
struct device_node *sib;
for_each_child_of_node(dn, sib)
eeh_add_device_tree_early(sib);
eeh_add_device_early(dn);
}
EXPORT_SYMBOL_GPL(eeh_add_device_tree_early);
/**
* eeh_add_device_late - Perform EEH initialization for the indicated pci device
* @dev: pci device for which to set up EEH
*
* This routine must be used to complete EEH initialization for PCI
* devices that were added after system boot (e.g. hotplug, dlpar).
*/
void eeh_add_device_late(struct pci_dev *dev)
{
struct device_node *dn;
struct eeh_dev *edev;
if (!dev || !eeh_enabled())
return;
pr_debug("EEH: Adding device %s\n", pci_name(dev));
dn = pci_device_to_OF_node(dev);
edev = of_node_to_eeh_dev(dn);
if (edev->pdev == dev) {
pr_debug("EEH: Already referenced !\n");
return;
}
/*
* The EEH cache might not be removed correctly because of
* unbalanced kref to the device during unplug time, which
* relies on pcibios_release_device(). So we have to remove
* that here explicitly.
*/
if (edev->pdev) {
eeh_rmv_from_parent_pe(edev);
eeh_addr_cache_rmv_dev(edev->pdev);
eeh_sysfs_remove_device(edev->pdev);
edev->mode &= ~EEH_DEV_SYSFS;
/*
* We definitely should have the PCI device removed
* though it wasn't correctly. So we needn't call
* into error handler afterwards.
*/
edev->mode |= EEH_DEV_NO_HANDLER;
edev->pdev = NULL;
dev->dev.archdata.edev = NULL;
}
edev->pdev = dev;
dev->dev.archdata.edev = edev;
/*
* We have to do the EEH probe here because the PCI device
* hasn't been created yet in the early stage.
*/
if (eeh_probe_mode_dev())
eeh_ops->dev_probe(dev, NULL);
eeh_addr_cache_insert_dev(dev);
}
/**
* eeh_add_device_tree_late - Perform EEH initialization for the indicated PCI bus
* @bus: PCI bus
*
* This routine must be used to perform EEH initialization for PCI
* devices which are attached to the indicated PCI bus. The PCI bus
* is added after system boot through hotplug or dlpar.
*/
void eeh_add_device_tree_late(struct pci_bus *bus)
{
struct pci_dev *dev;
list_for_each_entry(dev, &bus->devices, bus_list) {
eeh_add_device_late(dev);
if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
struct pci_bus *subbus = dev->subordinate;
if (subbus)
eeh_add_device_tree_late(subbus);
}
}
}
EXPORT_SYMBOL_GPL(eeh_add_device_tree_late);
/**
* eeh_add_sysfs_files - Add EEH sysfs files for the indicated PCI bus
* @bus: PCI bus
*
* This routine must be used to add EEH sysfs files for PCI
* devices which are attached to the indicated PCI bus. The PCI bus
* is added after system boot through hotplug or dlpar.
*/
void eeh_add_sysfs_files(struct pci_bus *bus)
{
struct pci_dev *dev;
list_for_each_entry(dev, &bus->devices, bus_list) {
eeh_sysfs_add_device(dev);
if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
struct pci_bus *subbus = dev->subordinate;
if (subbus)
eeh_add_sysfs_files(subbus);
}
}
}
EXPORT_SYMBOL_GPL(eeh_add_sysfs_files);
/**
* eeh_remove_device - Undo EEH setup for the indicated pci device
* @dev: pci device to be removed
*
* This routine should be called when a device is removed from
* a running system (e.g. by hotplug or dlpar). It unregisters
* the PCI device from the EEH subsystem. I/O errors affecting
* this device will no longer be detected after this call; thus,
* i/o errors affecting this slot may leave this device unusable.
*/
void eeh_remove_device(struct pci_dev *dev)
{
struct eeh_dev *edev;
if (!dev || !eeh_enabled())
return;
edev = pci_dev_to_eeh_dev(dev);
/* Unregister the device with the EEH/PCI address search system */
pr_debug("EEH: Removing device %s\n", pci_name(dev));
if (!edev || !edev->pdev || !edev->pe) {
pr_debug("EEH: Not referenced !\n");
return;
}
/*
* During the hotplug for EEH error recovery, we need the EEH
* device attached to the parent PE in order for BAR restore
* a bit later. So we keep it for BAR restore and remove it
* from the parent PE during the BAR resotre.
*/
edev->pdev = NULL;
dev->dev.archdata.edev = NULL;
if (!(edev->pe->state & EEH_PE_KEEP))
eeh_rmv_from_parent_pe(edev);
else
edev->mode |= EEH_DEV_DISCONNECTED;
/*
* We're removing from the PCI subsystem, that means
* the PCI device driver can't support EEH or not
* well. So we rely on hotplug completely to do recovery
* for the specific PCI device.
*/
edev->mode |= EEH_DEV_NO_HANDLER;
eeh_addr_cache_rmv_dev(dev);
eeh_sysfs_remove_device(dev);
edev->mode &= ~EEH_DEV_SYSFS;
}
static int proc_eeh_show(struct seq_file *m, void *v)
{
if (!eeh_enabled()) {
seq_printf(m, "EEH Subsystem is globally disabled\n");
seq_printf(m, "eeh_total_mmio_ffs=%llu\n", eeh_stats.total_mmio_ffs);
} else {
seq_printf(m, "EEH Subsystem is enabled\n");
seq_printf(m,
"no device=%llu\n"
"no device node=%llu\n"
"no config address=%llu\n"
"check not wanted=%llu\n"
"eeh_total_mmio_ffs=%llu\n"
"eeh_false_positives=%llu\n"
"eeh_slot_resets=%llu\n",
eeh_stats.no_device,
eeh_stats.no_dn,
eeh_stats.no_cfg_addr,
eeh_stats.ignored_check,
eeh_stats.total_mmio_ffs,
eeh_stats.false_positives,
eeh_stats.slot_resets);
}
return 0;
}
static int proc_eeh_open(struct inode *inode, struct file *file)
{
return single_open(file, proc_eeh_show, NULL);
}
static const struct file_operations proc_eeh_operations = {
.open = proc_eeh_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int __init eeh_init_proc(void)
{
if (machine_is(pseries) || machine_is(powernv))
proc_create("powerpc/eeh", 0, NULL, &proc_eeh_operations);
return 0;
}
__initcall(eeh_init_proc);