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Commit e22a2274 authored by Mahesh Salgaonkar's avatar Mahesh Salgaonkar Committed by Benjamin Herrenschmidt
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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: default avatarMahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 04407050

arch/powerpc/include/asm/bitops.h

+5 −0
Original line number Diff line number Diff line
@@ -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

 */

arch/powerpc/include/asm/mce.h

0 → 100644
+67 −0
Original line number Diff line number Diff line 
/*

 * 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__ */

arch/powerpc/kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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

arch/powerpc/kernel/cputable.c

+4 −0
Original line number Diff line number Diff line
@@ -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 */

arch/powerpc/kernel/mce_power.c

0 → 100644
+150 −0
Original line number Diff line number Diff line 
/*

 * 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;

}