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/*
* Machine check exception handling CPU-side for power7 and power8
*
* 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_power: " fmt
#include <linux/types.h>
#include <linux/ptrace.h>
#include <asm/mmu.h>
#include <asm/mce.h>
/* flush SLBs and reload */
static void flush_and_reload_slb(void)
{
struct slb_shadow *slb;
unsigned long i, n;
/* Invalidate all SLBs */
asm volatile("slbmte %0,%0; slbia" : : "r" (0));
#ifdef CONFIG_KVM_BOOK3S_HANDLER
/*
* If machine check is hit when in guest or in transition, we will
* only flush the SLBs and continue.
*/
if (get_paca()->kvm_hstate.in_guest)
return;
#endif
/* For host kernel, reload the SLBs from shadow SLB buffer. */
slb = get_slb_shadow();
if (!slb)
return;
n = min_t(u32, slb->persistent, SLB_MIN_SIZE);
/* Load up the SLB entries from shadow SLB */
for (i = 0; i < n; i++) {
unsigned long rb = slb->save_area[i].esid;
unsigned long rs = slb->save_area[i].vsid;
rb = (rb & ~0xFFFul) | i;
asm volatile("slbmte %0,%1" : : "r" (rs), "r" (rb));
}
}
static long mce_handle_derror(uint64_t dsisr, uint64_t slb_error_bits)
{
long handled = 1;
/*
* flush and reload SLBs for SLB errors and flush TLBs for TLB errors.
* reset the error bits whenever we handle them so that at the end
* we can check whether we handled all of them or not.
* */
if (dsisr & slb_error_bits) {
flush_and_reload_slb();
/* reset error bits */
dsisr &= ~(slb_error_bits);
}
if (dsisr & P7_DSISR_MC_TLB_MULTIHIT_MFTLB) {
if (cur_cpu_spec && cur_cpu_spec->flush_tlb)
cur_cpu_spec->flush_tlb(TLBIEL_INVAL_PAGE);
/* reset error bits */
dsisr &= ~P7_DSISR_MC_TLB_MULTIHIT_MFTLB;
}
/* Any other errors we don't understand? */
if (dsisr & 0xffffffffUL)
handled = 0;
return handled;
}
static long mce_handle_derror_p7(uint64_t dsisr)
{
return mce_handle_derror(dsisr, P7_DSISR_MC_SLB_ERRORS);
}
static long mce_handle_common_ierror(uint64_t srr1)
{
long handled = 0;
switch (P7_SRR1_MC_IFETCH(srr1)) {
case 0:
break;
case P7_SRR1_MC_IFETCH_SLB_PARITY:
case P7_SRR1_MC_IFETCH_SLB_MULTIHIT:
/* flush and reload SLBs for SLB errors. */
flush_and_reload_slb();
handled = 1;
break;
case P7_SRR1_MC_IFETCH_TLB_MULTIHIT:
if (cur_cpu_spec && cur_cpu_spec->flush_tlb) {
cur_cpu_spec->flush_tlb(TLBIEL_INVAL_PAGE);
handled = 1;
}
break;
default:
break;
}
return handled;
}
static long mce_handle_ierror_p7(uint64_t srr1)
{
long handled = 0;
handled = mce_handle_common_ierror(srr1);
if (P7_SRR1_MC_IFETCH(srr1) == P7_SRR1_MC_IFETCH_SLB_BOTH) {
flush_and_reload_slb();
handled = 1;
}
return handled;
}
long __machine_check_early_realmode_p7(struct pt_regs *regs)
{
uint64_t srr1;
long handled = 1;
srr1 = regs->msr;
if (P7_SRR1_MC_LOADSTORE(srr1))
handled = mce_handle_derror_p7(regs->dsisr);
else
handled = mce_handle_ierror_p7(srr1);
/* TODO: Decode machine check reason. */
return handled;
}
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