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linux/linux-5.4.31/arch/powerpc/platforms/pseries/ras.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2001 Dave Engebretsen IBM Corporation
*/
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/of.h>
#include <linux/fs.h>
#include <linux/reboot.h>
#include <linux/irq_work.h>
#include <asm/machdep.h>
#include <asm/rtas.h>
#include <asm/firmware.h>
#include <asm/mce.h>
#include "pseries.h"
static unsigned char ras_log_buf[RTAS_ERROR_LOG_MAX];
static DEFINE_SPINLOCK(ras_log_buf_lock);
static int ras_check_exception_token;
static void mce_process_errlog_event(struct irq_work *work);
static struct irq_work mce_errlog_process_work = {
.func = mce_process_errlog_event,
};
#define EPOW_SENSOR_TOKEN 9
#define EPOW_SENSOR_INDEX 0
/* EPOW events counter variable */
static int num_epow_events;
static irqreturn_t ras_hotplug_interrupt(int irq, void *dev_id);
static irqreturn_t ras_epow_interrupt(int irq, void *dev_id);
static irqreturn_t ras_error_interrupt(int irq, void *dev_id);
/* RTAS pseries MCE errorlog section. */
struct pseries_mc_errorlog {
__be32 fru_id;
__be32 proc_id;
u8 error_type;
/*
* sub_err_type (1 byte). Bit fields depends on error_type
*
* MSB0
* |
* V
* 01234567
* XXXXXXXX
*
* For error_type == MC_ERROR_TYPE_UE
* XXXXXXXX
* X 1: Permanent or Transient UE.
* X 1: Effective address provided.
* X 1: Logical address provided.
* XX 2: Reserved.
* XXX 3: Type of UE error.
*
* For error_type != MC_ERROR_TYPE_UE
* XXXXXXXX
* X 1: Effective address provided.
* XXXXX 5: Reserved.
* XX 2: Type of SLB/ERAT/TLB error.
*/
u8 sub_err_type;
u8 reserved_1[6];
__be64 effective_address;
__be64 logical_address;
} __packed;
/* RTAS pseries MCE error types */
#define MC_ERROR_TYPE_UE 0x00
#define MC_ERROR_TYPE_SLB 0x01
#define MC_ERROR_TYPE_ERAT 0x02
#define MC_ERROR_TYPE_UNKNOWN 0x03
#define MC_ERROR_TYPE_TLB 0x04
#define MC_ERROR_TYPE_D_CACHE 0x05
#define MC_ERROR_TYPE_I_CACHE 0x07
/* RTAS pseries MCE error sub types */
#define MC_ERROR_UE_INDETERMINATE 0
#define MC_ERROR_UE_IFETCH 1
#define MC_ERROR_UE_PAGE_TABLE_WALK_IFETCH 2
#define MC_ERROR_UE_LOAD_STORE 3
#define MC_ERROR_UE_PAGE_TABLE_WALK_LOAD_STORE 4
#define UE_EFFECTIVE_ADDR_PROVIDED 0x40
#define UE_LOGICAL_ADDR_PROVIDED 0x20
#define MC_ERROR_SLB_PARITY 0
#define MC_ERROR_SLB_MULTIHIT 1
#define MC_ERROR_SLB_INDETERMINATE 2
#define MC_ERROR_ERAT_PARITY 1
#define MC_ERROR_ERAT_MULTIHIT 2
#define MC_ERROR_ERAT_INDETERMINATE 3
#define MC_ERROR_TLB_PARITY 1
#define MC_ERROR_TLB_MULTIHIT 2
#define MC_ERROR_TLB_INDETERMINATE 3
static inline u8 rtas_mc_error_sub_type(const struct pseries_mc_errorlog *mlog)
{
switch (mlog->error_type) {
case MC_ERROR_TYPE_UE:
return (mlog->sub_err_type & 0x07);
case MC_ERROR_TYPE_SLB:
case MC_ERROR_TYPE_ERAT:
case MC_ERROR_TYPE_TLB:
return (mlog->sub_err_type & 0x03);
default:
return 0;
}
}
/*
* Enable the hotplug interrupt late because processing them may touch other
* devices or systems (e.g. hugepages) that have not been initialized at the
* subsys stage.
*/
int __init init_ras_hotplug_IRQ(void)
{
struct device_node *np;
/* Hotplug Events */
np = of_find_node_by_path("/event-sources/hot-plug-events");
if (np != NULL) {
if (dlpar_workqueue_init() == 0)
request_event_sources_irqs(np, ras_hotplug_interrupt,
"RAS_HOTPLUG");
of_node_put(np);
}
return 0;
}
machine_late_initcall(pseries, init_ras_hotplug_IRQ);
/*
* Initialize handlers for the set of interrupts caused by hardware errors
* and power system events.
*/
static int __init init_ras_IRQ(void)
{
struct device_node *np;
ras_check_exception_token = rtas_token("check-exception");
/* Internal Errors */
np = of_find_node_by_path("/event-sources/internal-errors");
if (np != NULL) {
request_event_sources_irqs(np, ras_error_interrupt,
"RAS_ERROR");
of_node_put(np);
}
/* EPOW Events */
np = of_find_node_by_path("/event-sources/epow-events");
if (np != NULL) {
request_event_sources_irqs(np, ras_epow_interrupt, "RAS_EPOW");
of_node_put(np);
}
return 0;
}
machine_subsys_initcall(pseries, init_ras_IRQ);
#define EPOW_SHUTDOWN_NORMAL 1
#define EPOW_SHUTDOWN_ON_UPS 2
#define EPOW_SHUTDOWN_LOSS_OF_CRITICAL_FUNCTIONS 3
#define EPOW_SHUTDOWN_AMBIENT_TEMPERATURE_TOO_HIGH 4
static void handle_system_shutdown(char event_modifier)
{
switch (event_modifier) {
case EPOW_SHUTDOWN_NORMAL:
pr_emerg("Power off requested\n");
orderly_poweroff(true);
break;
case EPOW_SHUTDOWN_ON_UPS:
pr_emerg("Loss of system power detected. System is running on"
" UPS/battery. Check RTAS error log for details\n");
orderly_poweroff(true);
break;
case EPOW_SHUTDOWN_LOSS_OF_CRITICAL_FUNCTIONS:
pr_emerg("Loss of system critical functions detected. Check"
" RTAS error log for details\n");
orderly_poweroff(true);
break;
case EPOW_SHUTDOWN_AMBIENT_TEMPERATURE_TOO_HIGH:
pr_emerg("High ambient temperature detected. Check RTAS"
" error log for details\n");
orderly_poweroff(true);
break;
default:
pr_err("Unknown power/cooling shutdown event (modifier = %d)\n",
event_modifier);
}
}
struct epow_errorlog {
unsigned char sensor_value;
unsigned char event_modifier;
unsigned char extended_modifier;
unsigned char reserved;
unsigned char platform_reason;
};
#define EPOW_RESET 0
#define EPOW_WARN_COOLING 1
#define EPOW_WARN_POWER 2
#define EPOW_SYSTEM_SHUTDOWN 3
#define EPOW_SYSTEM_HALT 4
#define EPOW_MAIN_ENCLOSURE 5
#define EPOW_POWER_OFF 7
static void rtas_parse_epow_errlog(struct rtas_error_log *log)
{
struct pseries_errorlog *pseries_log;
struct epow_errorlog *epow_log;
char action_code;
char modifier;
pseries_log = get_pseries_errorlog(log, PSERIES_ELOG_SECT_ID_EPOW);
if (pseries_log == NULL)
return;
epow_log = (struct epow_errorlog *)pseries_log->data;
action_code = epow_log->sensor_value & 0xF; /* bottom 4 bits */
modifier = epow_log->event_modifier & 0xF; /* bottom 4 bits */
switch (action_code) {
case EPOW_RESET:
if (num_epow_events) {
pr_info("Non critical power/cooling issue cleared\n");
num_epow_events--;
}
break;
case EPOW_WARN_COOLING:
pr_info("Non-critical cooling issue detected. Check RTAS error"
" log for details\n");
break;
case EPOW_WARN_POWER:
pr_info("Non-critical power issue detected. Check RTAS error"
" log for details\n");
break;
case EPOW_SYSTEM_SHUTDOWN:
handle_system_shutdown(epow_log->event_modifier);
break;
case EPOW_SYSTEM_HALT:
pr_emerg("Critical power/cooling issue detected. Check RTAS"
" error log for details. Powering off.\n");
orderly_poweroff(true);
break;
case EPOW_MAIN_ENCLOSURE:
case EPOW_POWER_OFF:
pr_emerg("System about to lose power. Check RTAS error log "
" for details. Powering off immediately.\n");
emergency_sync();
kernel_power_off();
break;
default:
pr_err("Unknown power/cooling event (action code = %d)\n",
action_code);
}
/* Increment epow events counter variable */
if (action_code != EPOW_RESET)
num_epow_events++;
}
static irqreturn_t ras_hotplug_interrupt(int irq, void *dev_id)
{
struct pseries_errorlog *pseries_log;
struct pseries_hp_errorlog *hp_elog;
spin_lock(&ras_log_buf_lock);
rtas_call(ras_check_exception_token, 6, 1, NULL,
RTAS_VECTOR_EXTERNAL_INTERRUPT, virq_to_hw(irq),
RTAS_HOTPLUG_EVENTS, 0, __pa(&ras_log_buf),
rtas_get_error_log_max());
pseries_log = get_pseries_errorlog((struct rtas_error_log *)ras_log_buf,
PSERIES_ELOG_SECT_ID_HOTPLUG);
hp_elog = (struct pseries_hp_errorlog *)pseries_log->data;
/*
* Since PCI hotplug is not currently supported on pseries, put PCI
* hotplug events on the ras_log_buf to be handled by rtas_errd.
*/
if (hp_elog->resource == PSERIES_HP_ELOG_RESOURCE_MEM ||
hp_elog->resource == PSERIES_HP_ELOG_RESOURCE_CPU ||
hp_elog->resource == PSERIES_HP_ELOG_RESOURCE_PMEM)
queue_hotplug_event(hp_elog);
else
log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, 0);
spin_unlock(&ras_log_buf_lock);
return IRQ_HANDLED;
}
/* Handle environmental and power warning (EPOW) interrupts. */
static irqreturn_t ras_epow_interrupt(int irq, void *dev_id)
{
int status;
int state;
int critical;
status = rtas_get_sensor_fast(EPOW_SENSOR_TOKEN, EPOW_SENSOR_INDEX,
&state);
if (state > 3)
critical = 1; /* Time Critical */
else
critical = 0;
spin_lock(&ras_log_buf_lock);
status = rtas_call(ras_check_exception_token, 6, 1, NULL,
RTAS_VECTOR_EXTERNAL_INTERRUPT,
virq_to_hw(irq),
RTAS_EPOW_WARNING,
critical, __pa(&ras_log_buf),
rtas_get_error_log_max());
log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, 0);
rtas_parse_epow_errlog((struct rtas_error_log *)ras_log_buf);
spin_unlock(&ras_log_buf_lock);
return IRQ_HANDLED;
}
/*
* Handle hardware error interrupts.
*
* RTAS check-exception is called to collect data on the exception. If
* the error is deemed recoverable, we log a warning and return.
* For nonrecoverable errors, an error is logged and we stop all processing
* as quickly as possible in order to prevent propagation of the failure.
*/
static irqreturn_t ras_error_interrupt(int irq, void *dev_id)
{
struct rtas_error_log *rtas_elog;
int status;
int fatal;
spin_lock(&ras_log_buf_lock);
status = rtas_call(ras_check_exception_token, 6, 1, NULL,
RTAS_VECTOR_EXTERNAL_INTERRUPT,
virq_to_hw(irq),
RTAS_INTERNAL_ERROR, 1 /* Time Critical */,
__pa(&ras_log_buf),
rtas_get_error_log_max());
rtas_elog = (struct rtas_error_log *)ras_log_buf;
if (status == 0 &&
rtas_error_severity(rtas_elog) >= RTAS_SEVERITY_ERROR_SYNC)
fatal = 1;
else
fatal = 0;
/* format and print the extended information */
log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, fatal);
if (fatal) {
pr_emerg("Fatal hardware error detected. Check RTAS error"
" log for details. Powering off immediately\n");
emergency_sync();
kernel_power_off();
} else {
pr_err("Recoverable hardware error detected\n");
}
spin_unlock(&ras_log_buf_lock);
return IRQ_HANDLED;
}
/*
* Some versions of FWNMI place the buffer inside the 4kB page starting at
* 0x7000. Other versions place it inside the rtas buffer. We check both.
*/
#define VALID_FWNMI_BUFFER(A) \
((((A) >= 0x7000) && ((A) < 0x7ff0)) || \
(((A) >= rtas.base) && ((A) < (rtas.base + rtas.size - 16))))
static inline struct rtas_error_log *fwnmi_get_errlog(void)
{
return (struct rtas_error_log *)local_paca->mce_data_buf;
}
/*
* Get the error information for errors coming through the
* FWNMI vectors. The pt_regs' r3 will be updated to reflect
* the actual r3 if possible, and a ptr to the error log entry
* will be returned if found.
*
* Use one buffer mce_data_buf per cpu to store RTAS error.
*
* The mce_data_buf does not have any locks or protection around it,
* if a second machine check comes in, or a system reset is done
* before we have logged the error, then we will get corruption in the
* error log. This is preferable over holding off on calling
* ibm,nmi-interlock which would result in us checkstopping if a
* second machine check did come in.
*/
static struct rtas_error_log *fwnmi_get_errinfo(struct pt_regs *regs)
{
unsigned long *savep;
struct rtas_error_log *h;
/* Mask top two bits */
regs->gpr[3] &= ~(0x3UL << 62);
if (!VALID_FWNMI_BUFFER(regs->gpr[3])) {
printk(KERN_ERR "FWNMI: corrupt r3 0x%016lx\n", regs->gpr[3]);
return NULL;
}
savep = __va(regs->gpr[3]);
regs->gpr[3] = be64_to_cpu(savep[0]); /* restore original r3 */
h = (struct rtas_error_log *)&savep[1];
/* Use the per cpu buffer from paca to store rtas error log */
memset(local_paca->mce_data_buf, 0, RTAS_ERROR_LOG_MAX);
if (!rtas_error_extended(h)) {
memcpy(local_paca->mce_data_buf, h, sizeof(__u64));
} else {
int len, error_log_length;
error_log_length = 8 + rtas_error_extended_log_length(h);
len = min_t(int, error_log_length, RTAS_ERROR_LOG_MAX);
memcpy(local_paca->mce_data_buf, h, len);
}
return (struct rtas_error_log *)local_paca->mce_data_buf;
}
/* Call this when done with the data returned by FWNMI_get_errinfo.
* It will release the saved data area for other CPUs in the
* partition to receive FWNMI errors.
*/
static void fwnmi_release_errinfo(void)
{
int ret = rtas_call(rtas_token("ibm,nmi-interlock"), 0, 1, NULL);
if (ret != 0)
printk(KERN_ERR "FWNMI: nmi-interlock failed: %d\n", ret);
}
int pSeries_system_reset_exception(struct pt_regs *regs)
{
#ifdef __LITTLE_ENDIAN__
/*
* Some firmware byteswaps SRR registers and gives incorrect SRR1. Try
* to detect the bad SRR1 pattern here. Flip the NIP back to correct
* endian for reporting purposes. Unfortunately the MSR can't be fixed,
* so clear it. It will be missing MSR_RI so we won't try to recover.
*/
if ((be64_to_cpu(regs->msr) &
(MSR_LE|MSR_RI|MSR_DR|MSR_IR|MSR_ME|MSR_PR|
MSR_ILE|MSR_HV|MSR_SF)) == (MSR_DR|MSR_SF)) {
regs->nip = be64_to_cpu((__be64)regs->nip);
regs->msr = 0;
}
#endif
if (fwnmi_active) {
struct rtas_error_log *errhdr = fwnmi_get_errinfo(regs);
if (errhdr) {
/* XXX Should look at FWNMI information */
}
fwnmi_release_errinfo();
}
if (smp_handle_nmi_ipi(regs))
return 1;
return 0; /* need to perform reset */
}
static int mce_handle_error(struct pt_regs *regs, struct rtas_error_log *errp)
{
struct mce_error_info mce_err = { 0 };
unsigned long eaddr = 0, paddr = 0;
struct pseries_errorlog *pseries_log;
struct pseries_mc_errorlog *mce_log;
int disposition = rtas_error_disposition(errp);
int initiator = rtas_error_initiator(errp);
int severity = rtas_error_severity(errp);
u8 error_type, err_sub_type;
if (initiator == RTAS_INITIATOR_UNKNOWN)
mce_err.initiator = MCE_INITIATOR_UNKNOWN;
else if (initiator == RTAS_INITIATOR_CPU)
mce_err.initiator = MCE_INITIATOR_CPU;
else if (initiator == RTAS_INITIATOR_PCI)
mce_err.initiator = MCE_INITIATOR_PCI;
else if (initiator == RTAS_INITIATOR_ISA)
mce_err.initiator = MCE_INITIATOR_ISA;
else if (initiator == RTAS_INITIATOR_MEMORY)
mce_err.initiator = MCE_INITIATOR_MEMORY;
else if (initiator == RTAS_INITIATOR_POWERMGM)
mce_err.initiator = MCE_INITIATOR_POWERMGM;
else
mce_err.initiator = MCE_INITIATOR_UNKNOWN;
if (severity == RTAS_SEVERITY_NO_ERROR)
mce_err.severity = MCE_SEV_NO_ERROR;
else if (severity == RTAS_SEVERITY_EVENT)
mce_err.severity = MCE_SEV_WARNING;
else if (severity == RTAS_SEVERITY_WARNING)
mce_err.severity = MCE_SEV_WARNING;
else if (severity == RTAS_SEVERITY_ERROR_SYNC)
mce_err.severity = MCE_SEV_SEVERE;
else if (severity == RTAS_SEVERITY_ERROR)
mce_err.severity = MCE_SEV_SEVERE;
else if (severity == RTAS_SEVERITY_FATAL)
mce_err.severity = MCE_SEV_FATAL;
else
mce_err.severity = MCE_SEV_FATAL;
if (severity <= RTAS_SEVERITY_ERROR_SYNC)
mce_err.sync_error = true;
else
mce_err.sync_error = false;
mce_err.error_type = MCE_ERROR_TYPE_UNKNOWN;
mce_err.error_class = MCE_ECLASS_UNKNOWN;
if (!rtas_error_extended(errp))
goto out;
pseries_log = get_pseries_errorlog(errp, PSERIES_ELOG_SECT_ID_MCE);
if (pseries_log == NULL)
goto out;
mce_log = (struct pseries_mc_errorlog *)pseries_log->data;
error_type = mce_log->error_type;
err_sub_type = rtas_mc_error_sub_type(mce_log);
switch (mce_log->error_type) {
case MC_ERROR_TYPE_UE:
mce_err.error_type = MCE_ERROR_TYPE_UE;
switch (err_sub_type) {
case MC_ERROR_UE_IFETCH:
mce_err.u.ue_error_type = MCE_UE_ERROR_IFETCH;
break;
case MC_ERROR_UE_PAGE_TABLE_WALK_IFETCH:
mce_err.u.ue_error_type = MCE_UE_ERROR_PAGE_TABLE_WALK_IFETCH;
break;
case MC_ERROR_UE_LOAD_STORE:
mce_err.u.ue_error_type = MCE_UE_ERROR_LOAD_STORE;
break;
case MC_ERROR_UE_PAGE_TABLE_WALK_LOAD_STORE:
mce_err.u.ue_error_type = MCE_UE_ERROR_PAGE_TABLE_WALK_LOAD_STORE;
break;
case MC_ERROR_UE_INDETERMINATE:
default:
mce_err.u.ue_error_type = MCE_UE_ERROR_INDETERMINATE;
break;
}
if (mce_log->sub_err_type & UE_EFFECTIVE_ADDR_PROVIDED)
eaddr = be64_to_cpu(mce_log->effective_address);
if (mce_log->sub_err_type & UE_LOGICAL_ADDR_PROVIDED) {
paddr = be64_to_cpu(mce_log->logical_address);
} else if (mce_log->sub_err_type & UE_EFFECTIVE_ADDR_PROVIDED) {
unsigned long pfn;
pfn = addr_to_pfn(regs, eaddr);
if (pfn != ULONG_MAX)
paddr = pfn << PAGE_SHIFT;
}
break;
case MC_ERROR_TYPE_SLB:
mce_err.error_type = MCE_ERROR_TYPE_SLB;
switch (err_sub_type) {
case MC_ERROR_SLB_PARITY:
mce_err.u.slb_error_type = MCE_SLB_ERROR_PARITY;
break;
case MC_ERROR_SLB_MULTIHIT:
mce_err.u.slb_error_type = MCE_SLB_ERROR_MULTIHIT;
break;
case MC_ERROR_SLB_INDETERMINATE:
default:
mce_err.u.slb_error_type = MCE_SLB_ERROR_INDETERMINATE;
break;
}
if (mce_log->sub_err_type & 0x80)
eaddr = be64_to_cpu(mce_log->effective_address);
break;
case MC_ERROR_TYPE_ERAT:
mce_err.error_type = MCE_ERROR_TYPE_ERAT;
switch (err_sub_type) {
case MC_ERROR_ERAT_PARITY:
mce_err.u.erat_error_type = MCE_ERAT_ERROR_PARITY;
break;
case MC_ERROR_ERAT_MULTIHIT:
mce_err.u.erat_error_type = MCE_ERAT_ERROR_MULTIHIT;
break;
case MC_ERROR_ERAT_INDETERMINATE:
default:
mce_err.u.erat_error_type = MCE_ERAT_ERROR_INDETERMINATE;
break;
}
if (mce_log->sub_err_type & 0x80)
eaddr = be64_to_cpu(mce_log->effective_address);
break;
case MC_ERROR_TYPE_TLB:
mce_err.error_type = MCE_ERROR_TYPE_TLB;
switch (err_sub_type) {
case MC_ERROR_TLB_PARITY:
mce_err.u.tlb_error_type = MCE_TLB_ERROR_PARITY;
break;
case MC_ERROR_TLB_MULTIHIT:
mce_err.u.tlb_error_type = MCE_TLB_ERROR_MULTIHIT;
break;
case MC_ERROR_TLB_INDETERMINATE:
default:
mce_err.u.tlb_error_type = MCE_TLB_ERROR_INDETERMINATE;
break;
}
if (mce_log->sub_err_type & 0x80)
eaddr = be64_to_cpu(mce_log->effective_address);
break;
case MC_ERROR_TYPE_D_CACHE:
mce_err.error_type = MCE_ERROR_TYPE_DCACHE;
break;
case MC_ERROR_TYPE_I_CACHE:
mce_err.error_type = MCE_ERROR_TYPE_DCACHE;
break;
case MC_ERROR_TYPE_UNKNOWN:
default:
mce_err.error_type = MCE_ERROR_TYPE_UNKNOWN;
break;
}
#ifdef CONFIG_PPC_BOOK3S_64
if (disposition == RTAS_DISP_NOT_RECOVERED) {
switch (error_type) {
case MC_ERROR_TYPE_SLB:
case MC_ERROR_TYPE_ERAT:
/*
* Store the old slb content in paca before flushing.
* Print this when we go to virtual mode.
* There are chances that we may hit MCE again if there
* is a parity error on the SLB entry we trying to read
* for saving. Hence limit the slb saving to single
* level of recursion.
*/
if (local_paca->in_mce == 1)
slb_save_contents(local_paca->mce_faulty_slbs);
flush_and_reload_slb();
disposition = RTAS_DISP_FULLY_RECOVERED;
break;
default:
break;
}
} else if (disposition == RTAS_DISP_LIMITED_RECOVERY) {
/* Platform corrected itself but could be degraded */
printk(KERN_ERR "MCE: limited recovery, system may "
"be degraded\n");
disposition = RTAS_DISP_FULLY_RECOVERED;
}
#endif
out:
save_mce_event(regs, disposition == RTAS_DISP_FULLY_RECOVERED,
&mce_err, regs->nip, eaddr, paddr);
return disposition;
}
/*
* Process MCE rtas errlog event.
*/
static void mce_process_errlog_event(struct irq_work *work)
{
struct rtas_error_log *err;
err = fwnmi_get_errlog();
log_error((char *)err, ERR_TYPE_RTAS_LOG, 0);
}
/*
* See if we can recover from a machine check exception.
* This is only called on power4 (or above) and only via
* the Firmware Non-Maskable Interrupts (fwnmi) handler
* which provides the error analysis for us.
*
* Return 1 if corrected (or delivered a signal).
* Return 0 if there is nothing we can do.
*/
static int recover_mce(struct pt_regs *regs, struct machine_check_event *evt)
{
int recovered = 0;
if (!(regs->msr & MSR_RI)) {
/* If MSR_RI isn't set, we cannot recover */
pr_err("Machine check interrupt unrecoverable: MSR(RI=0)\n");
recovered = 0;
} else if (evt->disposition == MCE_DISPOSITION_RECOVERED) {
/* Platform corrected itself */
recovered = 1;
} else if (evt->severity == MCE_SEV_FATAL) {
/* Fatal machine check */
pr_err("Machine check interrupt is fatal\n");
recovered = 0;
}
if (!recovered && evt->sync_error) {
/*
* Try to kill processes if we get a synchronous machine check
* (e.g., one caused by execution of this instruction). This
* will devolve into a panic if we try to kill init or are in
* an interrupt etc.
*
* TODO: Queue up this address for hwpoisioning later.
* TODO: This is not quite right for d-side machine
* checks ->nip is not necessarily the important
* address.
*/
if ((user_mode(regs))) {
_exception(SIGBUS, regs, BUS_MCEERR_AR, regs->nip);
recovered = 1;
} else if (die_will_crash()) {
/*
* die() would kill the kernel, so better to go via
* the platform reboot code that will log the
* machine check.
*/
recovered = 0;
} else {
die("Machine check", regs, SIGBUS);
recovered = 1;
}
}
return recovered;
}
/*
* Handle a machine check.
*
* Note that on Power 4 and beyond Firmware Non-Maskable Interrupts (fwnmi)
* should be present. If so the handler which called us tells us if the
* error was recovered (never true if RI=0).
*
* On hardware prior to Power 4 these exceptions were asynchronous which
* means we can't tell exactly where it occurred and so we can't recover.
*/
int pSeries_machine_check_exception(struct pt_regs *regs)
{
struct machine_check_event evt;
if (!get_mce_event(&evt, MCE_EVENT_RELEASE))
return 0;
/* Print things out */
if (evt.version != MCE_V1) {
pr_err("Machine Check Exception, Unknown event version %d !\n",
evt.version);
return 0;
}
machine_check_print_event_info(&evt, user_mode(regs), false);
if (recover_mce(regs, &evt))
return 1;
return 0;
}
long pseries_machine_check_realmode(struct pt_regs *regs)
{
struct rtas_error_log *errp;
int disposition;
if (fwnmi_active) {
errp = fwnmi_get_errinfo(regs);
/*
* Call to fwnmi_release_errinfo() in real mode causes kernel
* to panic. Hence we will call it as soon as we go into
* virtual mode.
*/
disposition = mce_handle_error(regs, errp);
fwnmi_release_errinfo();
/* Queue irq work to log this rtas event later. */
irq_work_queue(&mce_errlog_process_work);
if (disposition == RTAS_DISP_FULLY_RECOVERED)
return 1;
}
return 0;
}
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