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s390/mcck: move storage error checks to assembler

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The current storage errors tackling is wrong - the DAT is
enabled in assembler code before the actual storage checks
in C half are executed. In case the page tables themselves
are damaged such approach is not going to work.

With this update unrecoverable storage errors are not
passed to C code for handling, but rather the machine
is stopped right away. The only exception to this flow
is when a machine check occurred in KVM guest - in this
case the errors are reinjected by the handler.

Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Alexander Gordeev 2021-06-18 08:17:16 +02:00 committed by Vasily Gorbik
parent 7f6dc8d4c8
commit d35925b349
3 changed files with 36 additions and 26 deletions
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4
arch/s390/include/asm/nmi.h
View file

@ -24,8 +24,12 @@
#define MCCK_CODE_EXT_DAMAGE BIT(63 - 5)
#define MCCK_CODE_CP BIT(63 - 9)
#define MCCK_CODE_CPU_TIMER_VALID BIT(63 - 46)
#define MCCK_CODE_STG_ERROR BIT(63 - 16)
#define MCCK_CODE_STG_KEY_ERROR BIT(63 - 18)
#define MCCK_CODE_STG_DEGRAD BIT(63 - 19)
#define MCCK_CODE_PSW_MWP_VALID BIT(63 - 20)
#define MCCK_CODE_PSW_IA_VALID BIT(63 - 23)
#define MCCK_CODE_STG_FAIL_ADDR BIT(63 - 24)
#define MCCK_CODE_CR_VALID BIT(63 - 29)
#define MCCK_CODE_GS_VALID BIT(63 - 36)
#define MCCK_CODE_FC_VALID BIT(63 - 43)

43
arch/s390/kernel/entry.S
View file

@ -129,6 +129,24 @@ _LPP_OFFSET = __LC_LPP
"jnz .+8; .long 0xb2e8d000", 82
.endm
/*
* The CHKSTG macro jumps to the provided label in case the
* machine check interruption code reports one of unrecoverable
* storage errors:
* - Storage error uncorrected
* - Storage key error uncorrected
* - Storage degradation with Failing-storage-address validity
*/
.macro CHKSTG errlabel
TSTMSK __LC_MCCK_CODE,(MCCK_CODE_STG_ERROR|MCCK_CODE_STG_KEY_ERROR)
jnz \errlabel
TSTMSK __LC_MCCK_CODE,MCCK_CODE_STG_DEGRAD
jz oklabel\@
TSTMSK __LC_MCCK_CODE,MCCK_CODE_STG_FAIL_ADDR
jnz \errlabel
oklabel\@:
.endm
#if IS_ENABLED(CONFIG_KVM)
/*
* The OUTSIDE macro jumps to the provided label in case the value
@ -550,23 +568,26 @@ ENTRY(mcck_int_handler)
3: TSTMSK __LC_MCCK_CODE,MCCK_CODE_PSW_MWP_VALID
jno .Lmcck_panic
tmhh %r8,0x0001 # interrupting from user ?
jnz 4f
jnz 6f
TSTMSK __LC_MCCK_CODE,MCCK_CODE_PSW_IA_VALID
jno .Lmcck_panic
4: ssm __LC_PGM_NEW_PSW # turn dat on, keep irqs off
tmhh %r8,0x0001 # interrupting from user ?
#if IS_ENABLED(CONFIG_KVM)
jnz .Lmcck_user
OUTSIDE %r9,.Lsie_gmap,.Lsie_done,.Lmcck_stack
OUTSIDE %r9,.Lsie_entry,.Lsie_skip,5f
OUTSIDE %r9,.Lsie_gmap,.Lsie_done,6f
OUTSIDE %r9,.Lsie_entry,.Lsie_skip,4f
oi __LC_CPU_FLAGS+7, _CIF_MCCK_GUEST
5: BPENTER __SF_SIE_FLAGS(%r15),(_TIF_ISOLATE_BP|_TIF_ISOLATE_BP_GUEST)
j 5f
4: CHKSTG .Lmcck_panic
5: larl %r14,.Lstosm_tmp
stosm 0(%r14),0x04 # turn dat on, keep irqs off
BPENTER __SF_SIE_FLAGS(%r15),(_TIF_ISOLATE_BP|_TIF_ISOLATE_BP_GUEST)
SIEEXIT
j .Lmcck_stack
#else
jz .Lmcck_stack
#endif
.Lmcck_user:
6: CHKSTG .Lmcck_panic
larl %r14,.Lstosm_tmp
stosm 0(%r14),0x04 # turn dat on, keep irqs off
tmhh %r8,0x0001 # interrupting from user ?
jz .Lmcck_stack
BPENTER __TI_flags(%r12),_TIF_ISOLATE_BP
.Lmcck_stack:
lg %r15,__LC_MCCK_STACK
@ -692,7 +713,7 @@ ENDPROC(stack_overflow)
.align 4
.Lstop_lock: .long 0
.Lthis_cpu: .short 0
.Lstosm_tmp: .byte 0
.section .rodata, "a"
#define SYSCALL(esame,emu) .quad __s390x_ ## esame
.globl sys_call_table

15
arch/s390/kernel/nmi.c
View file

@ -399,21 +399,6 @@ int notrace s390_do_machine_check(struct pt_regs *regs)
mcck_pending = 1;
}
/*
* Reinject storage related machine checks into the guest if they
* happen when the guest is running.
*/
if (!test_cpu_flag(CIF_MCCK_GUEST)) {
if (mci.se)
/* Storage error uncorrected */
s390_handle_damage();
if (mci.ke)
/* Storage key-error uncorrected */
s390_handle_damage();
if (mci.ds && mci.fa)
/* Storage degradation */
s390_handle_damage();
}
if (mci.cp) {
/* Channel report word pending */
mcck->channel_report = 1;