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s390/nmi: move storage error checking back to C, enter with DAT on

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Checking for storage errors in machine check entry code was done in order
to handle also storage errors on kernel page tables. However this is
extremely unlikely and some basic assumptions what works on machine check
entry are necessary anyway. In order to simplify machine check handling
delay checking for storage errors to C code.
With this also change the machine check new PSW to have DAT on, which
simplifies the entry code even further.

Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
This commit is contained in:
Heiko Carstens 2022-11-29 17:22:14 +01:00 committed by Alexander Gordeev
parent 506faa5b9b
commit 742aed05af
3 changed files with 21 additions and 32 deletions
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34
arch/s390/kernel/entry.S
View file

@ -122,24 +122,6 @@ _LPP_OFFSET = __LC_LPP
"jnz .+8; .insn rrf,0xb2e80000,0,0,13,0", 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 .Loklabel\@
TSTMSK __LC_MCCK_CODE,MCCK_CODE_STG_FAIL_ADDR
jnz \errlabel
.Loklabel\@:
.endm
#if IS_ENABLED(CONFIG_KVM)
/*
* The OUTSIDE macro jumps to the provided label in case the value
@ -546,26 +528,18 @@ ENTRY(mcck_int_handler)
3: TSTMSK __LC_MCCK_CODE,MCCK_CODE_PSW_MWP_VALID
jno .Lmcck_panic
tmhh %r8,0x0001 # interrupting from user ?
jnz 6f
jnz .Lmcck_user
TSTMSK __LC_MCCK_CODE,MCCK_CODE_PSW_IA_VALID
jno .Lmcck_panic
#if IS_ENABLED(CONFIG_KVM)
OUTSIDE %r9,.Lsie_gmap,.Lsie_done,6f
OUTSIDE %r9,.Lsie_gmap,.Lsie_done,.Lmcck_stack
OUTSIDE %r9,.Lsie_entry,.Lsie_leave,4f
oi __LC_CPU_FLAGS+7, _CIF_MCCK_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)
4: BPENTER __SF_SIE_FLAGS(%r15),(_TIF_ISOLATE_BP|_TIF_ISOLATE_BP_GUEST)
SIEEXIT
j .Lmcck_stack
#endif
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
.Lmcck_user:
BPENTER __TI_flags(%r12),_TIF_ISOLATE_BP
.Lmcck_stack:
lg %r15,__LC_MCCK_STACK

16
arch/s390/kernel/nmi.c
View file

@ -487,7 +487,21 @@ int notrace s390_do_machine_check(struct pt_regs *regs)
mcck->stp_queue |= stp_island_check();
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)) {
/* Storage error uncorrected */
if (mci.se)
s390_handle_damage();
/* Storage key-error uncorrected */
if (mci.ke)
s390_handle_damage();
/* Storage degradation */
if (mci.ds && mci.fa)
s390_handle_damage();
}
if (mci.cp) {
/* Channel report word pending */
mcck->channel_report = 1;

3
arch/s390/kernel/setup.c
View file

@ -437,7 +437,7 @@ static void __init setup_lowcore_dat_off(void)
lc->svc_new_psw.addr = (unsigned long) system_call;
lc->program_new_psw.mask = int_psw_mask | PSW_MASK_MCHECK;
lc->program_new_psw.addr = (unsigned long) pgm_check_handler;
lc->mcck_new_psw.mask = PSW_KERNEL_BITS;
lc->mcck_new_psw.mask = int_psw_mask;
lc->mcck_new_psw.addr = (unsigned long) mcck_int_handler;
lc->io_new_psw.mask = int_psw_mask | PSW_MASK_MCHECK;
lc->io_new_psw.addr = (unsigned long) io_int_handler;
@ -512,6 +512,7 @@ static void __init setup_lowcore_dat_on(void)
S390_lowcore.external_new_psw.mask |= PSW_MASK_DAT;
S390_lowcore.svc_new_psw.mask |= PSW_MASK_DAT;
S390_lowcore.program_new_psw.mask |= PSW_MASK_DAT;
S390_lowcore.mcck_new_psw.mask |= PSW_MASK_DAT;
S390_lowcore.io_new_psw.mask |= PSW_MASK_DAT;
__ctl_set_bit(0, 28);
__ctl_store(S390_lowcore.cregs_save_area, 0, 15);