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powerpc/book3s: Flush SLB/TLBs if we get SLB/TLB machine check errors on power7. 

If we get a machine check exception due to SLB or TLB errors, then flush
SLBs/TLBs and reload SLBs to recover. We do this in real mode before turning
on MMU. Otherwise we would run into nested machine checks.

If we get a machine check when we are in guest, then just flush the
SLBs and continue. This patch handles errors for power7. The next
patch will handle errors for power8

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
hifive-unleashed-5.1
Mahesh Salgaonkar 2013-10-30 20:05:11 +05:30 committed by Benjamin Herrenschmidt
parent 0440705049
commit e22a22740c
5 changed files with 227 additions and 0 deletions
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5
arch/powerpc/include/asm/bitops.h
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@ -46,6 +46,11 @@
#include <asm/asm-compat.h>
#include <asm/synch.h>
/* PPC bit number conversion */
#define PPC_BITLSHIFT(be) (BITS_PER_LONG - 1 - (be))
#define PPC_BIT(bit) (1UL << PPC_BITLSHIFT(bit))
#define PPC_BITMASK(bs, be) ((PPC_BIT(bs) - PPC_BIT(be)) | PPC_BIT(bs))
/*
* clear_bit doesn't imply a memory barrier
*/

67
arch/powerpc/include/asm/mce.h 100644
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@ -0,0 +1,67 @@
/*
* Machine check exception header file.
*
* 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>
*/
#ifndef __ASM_PPC64_MCE_H__
#define __ASM_PPC64_MCE_H__
#include <linux/bitops.h>
/*
* Machine Check bits on power7 and power8
*/
#define P7_SRR1_MC_LOADSTORE(srr1) ((srr1) & PPC_BIT(42)) /* P8 too */
/* SRR1 bits for machine check (On Power7 and Power8) */
#define P7_SRR1_MC_IFETCH(srr1) ((srr1) & PPC_BITMASK(43, 45)) /* P8 too */
#define P7_SRR1_MC_IFETCH_UE (0x1 << PPC_BITLSHIFT(45)) /* P8 too */
#define P7_SRR1_MC_IFETCH_SLB_PARITY (0x2 << PPC_BITLSHIFT(45)) /* P8 too */
#define P7_SRR1_MC_IFETCH_SLB_MULTIHIT (0x3 << PPC_BITLSHIFT(45)) /* P8 too */
#define P7_SRR1_MC_IFETCH_SLB_BOTH (0x4 << PPC_BITLSHIFT(45))
#define P7_SRR1_MC_IFETCH_TLB_MULTIHIT (0x5 << PPC_BITLSHIFT(45)) /* P8 too */
#define P7_SRR1_MC_IFETCH_UE_TLB_RELOAD (0x6 << PPC_BITLSHIFT(45)) /* P8 too */
#define P7_SRR1_MC_IFETCH_UE_IFU_INTERNAL (0x7 << PPC_BITLSHIFT(45))
/* SRR1 bits for machine check (On Power8) */
#define P8_SRR1_MC_IFETCH_ERAT_MULTIHIT (0x4 << PPC_BITLSHIFT(45))
/* DSISR bits for machine check (On Power7 and Power8) */
#define P7_DSISR_MC_UE (PPC_BIT(48)) /* P8 too */
#define P7_DSISR_MC_UE_TABLEWALK (PPC_BIT(49)) /* P8 too */
#define P7_DSISR_MC_ERAT_MULTIHIT (PPC_BIT(52)) /* P8 too */
#define P7_DSISR_MC_TLB_MULTIHIT_MFTLB (PPC_BIT(53)) /* P8 too */
#define P7_DSISR_MC_SLB_PARITY_MFSLB (PPC_BIT(55)) /* P8 too */
#define P7_DSISR_MC_SLB_MULTIHIT (PPC_BIT(56)) /* P8 too */
#define P7_DSISR_MC_SLB_MULTIHIT_PARITY (PPC_BIT(57)) /* P8 too */
/*
* DSISR bits for machine check (Power8) in addition to above.
* Secondary DERAT Multihit
*/
#define P8_DSISR_MC_ERAT_MULTIHIT_SEC (PPC_BIT(54))
/* SLB error bits */
#define P7_DSISR_MC_SLB_ERRORS (P7_DSISR_MC_ERAT_MULTIHIT | \
P7_DSISR_MC_SLB_PARITY_MFSLB | \
P7_DSISR_MC_SLB_MULTIHIT | \
P7_DSISR_MC_SLB_MULTIHIT_PARITY)
#endif /* __ASM_PPC64_MCE_H__ */

1
arch/powerpc/kernel/Makefile
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@ -39,6 +39,7 @@ obj-$(CONFIG_PPC64) += setup_64.o sys_ppc32.o \
obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
obj-$(CONFIG_PPC_BOOK3S_64) += cpu_setup_ppc970.o cpu_setup_pa6t.o
obj-$(CONFIG_PPC_BOOK3S_64) += cpu_setup_power.o
obj-$(CONFIG_PPC_BOOK3S_64) += mce_power.o
obj64-$(CONFIG_RELOCATABLE) += reloc_64.o
obj-$(CONFIG_PPC_BOOK3E_64) += exceptions-64e.o idle_book3e.o
obj-$(CONFIG_PPC_A2) += cpu_setup_a2.o

4
arch/powerpc/kernel/cputable.c
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@ -73,6 +73,7 @@ extern void __restore_cpu_power8(void);
extern void __restore_cpu_a2(void);
extern void __flush_tlb_power7(unsigned long inval_selector);
extern void __flush_tlb_power8(unsigned long inval_selector);
extern long __machine_check_early_realmode_p7(struct pt_regs *regs);
#endif /* CONFIG_PPC64 */
#if defined(CONFIG_E500)
extern void __setup_cpu_e5500(unsigned long offset, struct cpu_spec* spec);
@ -443,6 +444,7 @@ static struct cpu_spec __initdata cpu_specs[] = {
.cpu_setup = __setup_cpu_power7,
.cpu_restore = __restore_cpu_power7,
.flush_tlb = __flush_tlb_power7,
.machine_check_early = __machine_check_early_realmode_p7,
.platform = "power7",
},
{ /* 2.07-compliant processor, i.e. Power8 "architected" mode */
@ -479,6 +481,7 @@ static struct cpu_spec __initdata cpu_specs[] = {
.cpu_setup = __setup_cpu_power7,
.cpu_restore = __restore_cpu_power7,
.flush_tlb = __flush_tlb_power7,
.machine_check_early = __machine_check_early_realmode_p7,
.platform = "power7",
},
{ /* Power7+ */
@ -498,6 +501,7 @@ static struct cpu_spec __initdata cpu_specs[] = {
.cpu_setup = __setup_cpu_power7,
.cpu_restore = __restore_cpu_power7,
.flush_tlb = __flush_tlb_power7,
.machine_check_early = __machine_check_early_realmode_p7,
.platform = "power7+",
},
{ /* Power8E */

150
arch/powerpc/kernel/mce_power.c 100644
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@ -0,0 +1,150 @@
/*
* 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;
}