From d35925b34996196d22a4357dc5212ab03af75151 Mon Sep 17 00:00:00 2001 From: Alexander Gordeev Date: Fri, 18 Jun 2021 08:17:16 +0200 Subject: [PATCH] s390/mcck: move storage error checks to assembler 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 Reviewed-by: Heiko Carstens Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik --- arch/s390/include/asm/nmi.h | 4 ++++ arch/s390/kernel/entry.S | 43 ++++++++++++++++++++++++++++++++----------- arch/s390/kernel/nmi.c | 15 --------------- 3 files changed, 36 insertions(+), 26 deletions(-) diff --git a/arch/s390/include/asm/nmi.h b/arch/s390/include/asm/nmi.h index 20e51c9ff240..5e1307486984 100644 --- a/arch/s390/include/asm/nmi.h +++ b/arch/s390/include/asm/nmi.h @@ -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) diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index 6bc8ed800458..8f72a8f9bc33 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -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 diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c index a424f6e69b95..fdb5d23ac995 100644 --- a/arch/s390/kernel/nmi.c +++ b/arch/s390/kernel/nmi.c @@ -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; -- 2.11.0