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/*
* Machine check exception handling.
*
* 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.
*
* Copyright 2013 IBM Corporation
* Author: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
*/
#undef DEBUG
#define pr_fmt(fmt) "mce: " fmt
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/percpu.h>
#include <linux/export.h>
#include <linux/irq_work.h>
#include <asm/mce.h>
static DEFINE_PER_CPU(int, mce_nest_count);
static DEFINE_PER_CPU(struct machine_check_event[MAX_MC_EVT], mce_event);
/* Queue for delayed MCE events. */
static DEFINE_PER_CPU(int, mce_queue_count);
static DEFINE_PER_CPU(struct machine_check_event[MAX_MC_EVT], mce_event_queue);
static void machine_check_process_queued_event(struct irq_work *work);
static struct irq_work mce_event_process_work = {
.func = machine_check_process_queued_event,
};
static void mce_set_error_info(struct machine_check_event *mce,
struct mce_error_info *mce_err)
{
mce->error_type = mce_err->error_type;
switch (mce_err->error_type) {
case MCE_ERROR_TYPE_UE:
mce->u.ue_error.ue_error_type = mce_err->u.ue_error_type;
break;
case MCE_ERROR_TYPE_SLB:
mce->u.slb_error.slb_error_type = mce_err->u.slb_error_type;
break;
case MCE_ERROR_TYPE_ERAT:
mce->u.erat_error.erat_error_type = mce_err->u.erat_error_type;
break;
case MCE_ERROR_TYPE_TLB:
mce->u.tlb_error.tlb_error_type = mce_err->u.tlb_error_type;
break;
case MCE_ERROR_TYPE_USER:
mce->u.user_error.user_error_type = mce_err->u.user_error_type;
break;
case MCE_ERROR_TYPE_RA:
mce->u.ra_error.ra_error_type = mce_err->u.ra_error_type;
break;
case MCE_ERROR_TYPE_LINK:
mce->u.link_error.link_error_type = mce_err->u.link_error_type;
break;
case MCE_ERROR_TYPE_UNKNOWN:
default:
break;
}
}
/*
* Decode and save high level MCE information into per cpu buffer which
* is an array of machine_check_event structure.
*/
void save_mce_event(struct pt_regs *regs, long handled,
struct mce_error_info *mce_err,
uint64_t nip, uint64_t addr)
{
int index = __this_cpu_inc_return(mce_nest_count) - 1;
struct machine_check_event *mce = this_cpu_ptr(&mce_event[index]);
/*
* Return if we don't have enough space to log mce event.
* mce_nest_count may go beyond MAX_MC_EVT but that's ok,
* the check below will stop buffer overrun.
*/
if (index >= MAX_MC_EVT)
return;
/* Populate generic machine check info */
mce->version = MCE_V1;
mce->srr0 = nip;
mce->srr1 = regs->msr;
mce->gpr3 = regs->gpr[3];
mce->in_use = 1;
/* Mark it recovered if we have handled it and MSR(RI=1). */
if (handled && (regs->msr & MSR_RI))
mce->disposition = MCE_DISPOSITION_RECOVERED;
else
mce->disposition = MCE_DISPOSITION_NOT_RECOVERED;
mce->initiator = mce_err->initiator;
mce->severity = mce_err->severity;
/*
* Populate the mce error_type and type-specific error_type.
*/
mce_set_error_info(mce, mce_err);
if (!addr)
return;
if (mce->error_type == MCE_ERROR_TYPE_TLB) {
mce->u.tlb_error.effective_address_provided = true;
mce->u.tlb_error.effective_address = addr;
} else if (mce->error_type == MCE_ERROR_TYPE_SLB) {
mce->u.slb_error.effective_address_provided = true;
mce->u.slb_error.effective_address = addr;
} else if (mce->error_type == MCE_ERROR_TYPE_ERAT) {
mce->u.erat_error.effective_address_provided = true;
mce->u.erat_error.effective_address = addr;
} else if (mce->error_type == MCE_ERROR_TYPE_USER) {
mce->u.user_error.effective_address_provided = true;
mce->u.user_error.effective_address = addr;
} else if (mce->error_type == MCE_ERROR_TYPE_RA) {
mce->u.ra_error.effective_address_provided = true;
mce->u.ra_error.effective_address = addr;
} else if (mce->error_type == MCE_ERROR_TYPE_LINK) {
mce->u.link_error.effective_address_provided = true;
mce->u.link_error.effective_address = addr;
} else if (mce->error_type == MCE_ERROR_TYPE_UE) {
mce->u.ue_error.effective_address_provided = true;
mce->u.ue_error.effective_address = addr;
}
return;
}
/*
* get_mce_event:
* mce Pointer to machine_check_event structure to be filled.
* release Flag to indicate whether to free the event slot or not.
* 0 <= do not release the mce event. Caller will invoke
* release_mce_event() once event has been consumed.
* 1 <= release the slot.
*
* return 1 = success
* 0 = failure
*
* get_mce_event() will be called by platform specific machine check
* handle routine and in KVM.
* When we call get_mce_event(), we are still in interrupt context and
* preemption will not be scheduled until ret_from_expect() routine
* is called.
*/
int get_mce_event(struct machine_check_event *mce, bool release)
{
int index = __this_cpu_read(mce_nest_count) - 1;
struct machine_check_event *mc_evt;
int ret = 0;
/* Sanity check */
if (index < 0)
return ret;
/* Check if we have MCE info to process. */
if (index < MAX_MC_EVT) {
mc_evt = this_cpu_ptr(&mce_event[index]);
/* Copy the event structure and release the original */
if (mce)
*mce = *mc_evt;
if (release)
mc_evt->in_use = 0;
ret = 1;
}
/* Decrement the count to free the slot. */
if (release)
__this_cpu_dec(mce_nest_count);
return ret;
}
void release_mce_event(void)
{
get_mce_event(NULL, true);
}
/*
* Queue up the MCE event which then can be handled later.
*/
void machine_check_queue_event(void)
{
int index;
struct machine_check_event evt;
if (!get_mce_event(&evt, MCE_EVENT_RELEASE))
return;
index = __this_cpu_inc_return(mce_queue_count) - 1;
/* If queue is full, just return for now. */
if (index >= MAX_MC_EVT) {
__this_cpu_dec(mce_queue_count);
return;
}
memcpy(this_cpu_ptr(&mce_event_queue[index]), &evt, sizeof(evt));
/* Queue irq work to process this event later. */
irq_work_queue(&mce_event_process_work);
}
/*
* process pending MCE event from the mce event queue. This function will be
* called during syscall exit.
*/
static void machine_check_process_queued_event(struct irq_work *work)
{
int index;
add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
/*
* For now just print it to console.
* TODO: log this error event to FSP or nvram.
*/
while (__this_cpu_read(mce_queue_count) > 0) {
index = __this_cpu_read(mce_queue_count) - 1;
machine_check_print_event_info(
this_cpu_ptr(&mce_event_queue[index]), false);
__this_cpu_dec(mce_queue_count);
}
}
void machine_check_print_event_info(struct machine_check_event *evt,
bool user_mode)
{
const char *level, *sevstr, *subtype;
static const char *mc_ue_types[] = {
"Indeterminate",
"Instruction fetch",
"Page table walk ifetch",
"Load/Store",
"Page table walk Load/Store",
};
static const char *mc_slb_types[] = {
"Indeterminate",
"Parity",
"Multihit",
};
static const char *mc_erat_types[] = {
"Indeterminate",
"Parity",
"Multihit",
};
static const char *mc_tlb_types[] = {
"Indeterminate",
"Parity",
"Multihit",
};
static const char *mc_user_types[] = {
"Indeterminate",
"tlbie(l) invalid",
};
static const char *mc_ra_types[] = {
"Indeterminate",
"Instruction fetch (bad)",
"Page table walk ifetch (bad)",
"Pag
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