| Message ID | 153365142349.14256.9954484737438718329.stgit@jupiter.in.ibm.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | powerpc/pseries: Machine check handler improvements. | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | warning | next/apply_patch Patch failed to apply |
| snowpatch_ozlabs/apply_patch | fail | Failed to apply to any branch |
Hello, On Tue, 07 Aug 2018 19:47:14 +0530 "Mahesh J Salgaonkar" <mahesh@linux.vnet.ibm.com> wrote: > From: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> > > On pseries, as of today system crashes if we get a machine check > exceptions due to SLB errors. These are soft errors and can be fixed > by flushing the SLBs so the kernel can continue to function instead of > system crash. We do this in real mode before turning on MMU. Otherwise > we would run into nested machine checks. This patch now fetches the > rtas error log in real mode and flushes the SLBs on SLB errors. > > Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> > Signed-off-by: Michal Suchanek <msuchanek@suse.com> > --- > > Changes in V7: > - Fold Michal's patch into this patch. > - Handle MSR_RI=0 and evil context case in MC handler. > --- > arch/powerpc/include/asm/book3s/64/mmu-hash.h | 1 > arch/powerpc/include/asm/machdep.h | 1 > arch/powerpc/kernel/exceptions-64s.S | 112 > +++++++++++++++++++++++++ > arch/powerpc/kernel/mce.c | 15 +++ > arch/powerpc/mm/slb.c | 6 + > arch/powerpc/platforms/powernv/setup.c | 11 ++ > arch/powerpc/platforms/pseries/pseries.h | 1 > arch/powerpc/platforms/pseries/ras.c | 51 +++++++++++ > arch/powerpc/platforms/pseries/setup.c | 1 9 files changed, > 195 insertions(+), 4 deletions(-) > > diff --git a/arch/powerpc/include/asm/book3s/64/mmu-hash.h > b/arch/powerpc/include/asm/book3s/64/mmu-hash.h index > 50ed64fba4ae..cc00a7088cf3 100644 --- > a/arch/powerpc/include/asm/book3s/64/mmu-hash.h +++ > b/arch/powerpc/include/asm/book3s/64/mmu-hash.h @@ -487,6 +487,7 @@ > extern void hpte_init_native(void); > extern void slb_initialize(void); > extern void slb_flush_and_rebolt(void); > +extern void slb_flush_and_rebolt_realmode(void); > > extern void slb_vmalloc_update(void); > extern void slb_set_size(u16 size); > diff --git a/arch/powerpc/include/asm/machdep.h > b/arch/powerpc/include/asm/machdep.h index a47de82fb8e2..b4831f1338db > 100644 --- a/arch/powerpc/include/asm/machdep.h > +++ b/arch/powerpc/include/asm/machdep.h > @@ -108,6 +108,7 @@ struct machdep_calls { > > /* Early exception handlers called in realmode */ > int (*hmi_exception_early)(struct pt_regs > *regs); > + long (*machine_check_early)(struct pt_regs > *regs); > /* Called during machine check exception to retrive fixup > address. */ bool (*mce_check_early_recovery)(struct > pt_regs *regs); diff --git a/arch/powerpc/kernel/exceptions-64s.S > b/arch/powerpc/kernel/exceptions-64s.S index > 285c6465324a..cb06f219570a 100644 --- > a/arch/powerpc/kernel/exceptions-64s.S +++ > b/arch/powerpc/kernel/exceptions-64s.S @@ -332,6 +332,9 @@ > TRAMP_REAL_BEGIN(machine_check_pSeries) machine_check_fwnmi: > SET_SCRATCH0(r13) /* save r13 */ > EXCEPTION_PROLOG_0(PACA_EXMC) > +BEGIN_FTR_SECTION > + b machine_check_pSeries_early > +END_FTR_SECTION_IFCLR(CPU_FTR_HVMODE) > machine_check_pSeries_0: > EXCEPTION_PROLOG_1(PACA_EXMC, KVMTEST_PR, 0x200) > /* > @@ -343,6 +346,90 @@ machine_check_pSeries_0: > > TRAMP_KVM_SKIP(PACA_EXMC, 0x200) > > +TRAMP_REAL_BEGIN(machine_check_pSeries_early) > +BEGIN_FTR_SECTION > + EXCEPTION_PROLOG_1(PACA_EXMC, NOTEST, 0x200) > + mr r10,r1 /* Save r1 */ > + ld r1,PACAMCEMERGSP(r13) /* Use MC emergency > stack */ > + subi r1,r1,INT_FRAME_SIZE /* alloc stack > frame */ > + mfspr r11,SPRN_SRR0 /* Save SRR0 */ > + mfspr r12,SPRN_SRR1 /* Save SRR1 */ > + EXCEPTION_PROLOG_COMMON_1() > + EXCEPTION_PROLOG_COMMON_2(PACA_EXMC) > + EXCEPTION_PROLOG_COMMON_3(0x200) > + addi r3,r1,STACK_FRAME_OVERHEAD > + BRANCH_LINK_TO_FAR(machine_check_early) /* Function call ABI > */ > + ld r12,_MSR(r1) > + andi. r11,r12,MSR_PR /* See if coming > from user. */ > + bne 2f /* continue in V mode > if we are. */ + > + /* > + * At this point we are not sure about what context we come > from. > + * We may be in the middle of swithing stack. r1 may not be > valid. > + * Hence stay on emergency stack, call > machine_check_exception and > + * return from the interrupt. > + * But before that, check if this is an un-recoverable > exception. > + * If yes, then stay on emergency stack and panic. > + */ > + andi. r11,r12,MSR_RI > + bne 1f > + > + /* > + * Check if we have successfully handled/recovered from > error, if not > + * then stay on emergency stack and panic. > + */ > + cmpdi r3,0 /* see if we handled MCE > successfully */ > + bne 1f /* if handled then return from > interrupt */ + > + LOAD_HANDLER(r10,unrecover_mce) > + mtspr SPRN_SRR0,r10 > + ld r10,PACAKMSR(r13) > + /* > + * We are going down. But there are chances that we might > get hit by > + * another MCE during panic path and we may run into > unstable state > + * with no way out. Hence, turn ME bit off while going down, > so that > + * when another MCE is hit during panic path, hypervisor will > + * power cycle the lpar, instead of getting into MCE loop. > + */ > + li r3,MSR_ME > + andc r10,r10,r3 /* Turn off MSR_ME */ > + mtspr SPRN_SRR1,r10 > + RFI_TO_KERNEL > + b . > + > + /* Stay on emergency stack and return from interrupt. */ > +1: LOAD_HANDLER(r10,mce_return) > + mtspr SPRN_SRR0,r10 > + ld r10,PACAKMSR(r13) > + mtspr SPRN_SRR1,r10 > + RFI_TO_KERNEL > + b . I think that the logic should be inverted here. That is we should check for unrecoverable and unhandled exceptions and jump to unrecov_mce if found, fallthrough to mce_return otherwise. Thanks Michal > + > + /* Move original SRR0 and SRR1 into the respective regs */ > +2: ld r9,_MSR(r1) > + mtspr SPRN_SRR1,r9 > + ld r3,_NIP(r1) > + mtspr SPRN_SRR0,r3 > + ld r9,_CTR(r1) > + mtctr r9 > + ld r9,_XER(r1) > + mtxer r9 > + ld r9,_LINK(r1) > + mtlr r9 > + REST_GPR(0, r1) > + REST_8GPRS(2, r1) > + REST_GPR(10, r1) > + ld r11,_CCR(r1) > + mtcr r11 > + REST_GPR(11, r1) > + REST_2GPRS(12, r1) > + /* restore original r1. */ > + ld r1,GPR1(r1) > + SET_SCRATCH0(r13) /* save r13 */ > + EXCEPTION_PROLOG_0(PACA_EXMC) > + b machine_check_pSeries_0 > +END_FTR_SECTION_IFCLR(CPU_FTR_HVMODE) > + > EXC_COMMON_BEGIN(machine_check_common) > /* > * Machine check is different because we use a different > @@ -536,6 +623,31 @@ EXC_COMMON_BEGIN(unrecover_mce) > bl unrecoverable_exception > b 1b > > +EXC_COMMON_BEGIN(mce_return) > + /* Invoke machine_check_exception to print MCE event and > return. */ > + addi r3,r1,STACK_FRAME_OVERHEAD > + bl machine_check_exception > + ld r9,_MSR(r1) > + mtspr SPRN_SRR1,r9 > + ld r3,_NIP(r1) > + mtspr SPRN_SRR0,r3 > + ld r9,_CTR(r1) > + mtctr r9 > + ld r9,_XER(r1) > + mtxer r9 > + ld r9,_LINK(r1) > + mtlr r9 > + REST_GPR(0, r1) > + REST_8GPRS(2, r1) > + REST_GPR(10, r1) > + ld r11,_CCR(r1) > + mtcr r11 > + REST_GPR(11, r1) > + REST_2GPRS(12, r1) > + /* restore original r1. */ > + ld r1,GPR1(r1) > + RFI_TO_KERNEL > + b . > > EXC_REAL(data_access, 0x300, 0x80) > EXC_VIRT(data_access, 0x4300, 0x80, 0x300) > diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c > index efdd16a79075..ae17d8aa60c4 100644 > --- a/arch/powerpc/kernel/mce.c > +++ b/arch/powerpc/kernel/mce.c > @@ -488,10 +488,19 @@ long machine_check_early(struct pt_regs *regs) > { > long handled = 0; > > - __this_cpu_inc(irq_stat.mce_exceptions); > + /* > + * For pSeries we count mce when we go into virtual mode > machine > + * check handler. Hence skip it. Also, We can't access per > cpu > + * variables in real mode for LPAR. > + */ > + if (early_cpu_has_feature(CPU_FTR_HVMODE)) > + __this_cpu_inc(irq_stat.mce_exceptions); > > - if (cur_cpu_spec && cur_cpu_spec->machine_check_early) > - handled = cur_cpu_spec->machine_check_early(regs); > + /* > + * See if platform is capable of handling machine check. > + */ > + if (ppc_md.machine_check_early) > + handled = ppc_md.machine_check_early(regs); > return handled; > } > > diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c > index cb796724a6fc..e89f675f1b5e 100644 > --- a/arch/powerpc/mm/slb.c > +++ b/arch/powerpc/mm/slb.c > @@ -145,6 +145,12 @@ void slb_flush_and_rebolt(void) > get_paca()->slb_cache_ptr = 0; > } > > +void slb_flush_and_rebolt_realmode(void) > +{ > + __slb_flush_and_rebolt(); > + get_paca()->slb_cache_ptr = 0; > +} > + > void slb_vmalloc_update(void) > { > unsigned long vflags; > diff --git a/arch/powerpc/platforms/powernv/setup.c > b/arch/powerpc/platforms/powernv/setup.c index > f96df0a25d05..b74c93bc2e55 100644 --- > a/arch/powerpc/platforms/powernv/setup.c +++ > b/arch/powerpc/platforms/powernv/setup.c @@ -431,6 +431,16 @@ static > unsigned long pnv_get_proc_freq(unsigned int cpu) return ret_freq; > } > > +static long pnv_machine_check_early(struct pt_regs *regs) > +{ > + long handled = 0; > + > + if (cur_cpu_spec && cur_cpu_spec->machine_check_early) > + handled = cur_cpu_spec->machine_check_early(regs); > + > + return handled; > +} > + > define_machine(powernv) { > .name = "PowerNV", > .probe = pnv_probe, > @@ -442,6 +452,7 @@ define_machine(powernv) { > .machine_shutdown = pnv_shutdown, > .power_save = NULL, > .calibrate_decr = generic_calibrate_decr, > + .machine_check_early = pnv_machine_check_early, > #ifdef CONFIG_KEXEC_CORE > .kexec_cpu_down = pnv_kexec_cpu_down, > #endif > diff --git a/arch/powerpc/platforms/pseries/pseries.h > b/arch/powerpc/platforms/pseries/pseries.h index > 60db2ee511fb..ec2a5f61d4a4 100644 --- > a/arch/powerpc/platforms/pseries/pseries.h +++ > b/arch/powerpc/platforms/pseries/pseries.h @@ -24,6 +24,7 @@ struct > pt_regs; > extern int pSeries_system_reset_exception(struct pt_regs *regs); > extern int pSeries_machine_check_exception(struct pt_regs *regs); > +extern long pSeries_machine_check_realmode(struct pt_regs *regs); > > #ifdef CONFIG_SMP > extern void smp_init_pseries(void); > diff --git a/arch/powerpc/platforms/pseries/ras.c > b/arch/powerpc/platforms/pseries/ras.c index > 851ce326874a..e4420f7c8fda 100644 --- > a/arch/powerpc/platforms/pseries/ras.c +++ > b/arch/powerpc/platforms/pseries/ras.c @@ -427,6 +427,35 @@ int > pSeries_system_reset_exception(struct pt_regs *regs) return 0; /* > need to perform reset */ } > > +static int mce_handle_error(struct rtas_error_log *errp) > +{ > + struct pseries_errorlog *pseries_log; > + struct pseries_mc_errorlog *mce_log; > + int disposition = rtas_error_disposition(errp); > + uint8_t error_type; > + > + if (!rtas_error_extended(errp)) > + goto out; > + > + pseries_log = get_pseries_errorlog(errp, > PSERIES_ELOG_SECT_ID_MCE); > + if (pseries_log == NULL) > + goto out; > + > + mce_log = (struct pseries_mc_errorlog *)pseries_log->data; > + error_type = rtas_mc_error_type(mce_log); > + > + if ((disposition == RTAS_DISP_NOT_RECOVERED) && > + (error_type == PSERIES_MC_ERROR_TYPE_SLB)) { > + /* Store the old slb content someplace. */ > + slb_flush_and_rebolt_realmode(); > + disposition = RTAS_DISP_FULLY_RECOVERED; > + rtas_set_disposition_recovered(errp); > + } > + > +out: > + return disposition; > +} > + > /* > * Process MCE rtas errlog event. > */ > @@ -503,11 +532,31 @@ int pSeries_machine_check_exception(struct > pt_regs *regs) struct rtas_error_log *errp; > > if (fwnmi_active) { > - errp = fwnmi_get_errinfo(regs); > fwnmi_release_errinfo(); > + errp = fwnmi_get_errlog(); > if (errp && recover_mce(regs, errp)) > return 1; > } > > return 0; > } > + > +long pSeries_machine_check_realmode(struct pt_regs *regs) > +{ > + struct rtas_error_log *errp; > + int disposition; > + > + if (fwnmi_active) { > + errp = fwnmi_get_errinfo(regs); > + /* > + * Call to fwnmi_release_errinfo() in real mode > causes kernel > + * to panic. Hence we will call it as soon as we go > into > + * virtual mode. > + */ > + disposition = mce_handle_error(errp); > + if (disposition == RTAS_DISP_FULLY_RECOVERED) > + return 1; > + } > + > + return 0; > +} > diff --git a/arch/powerpc/platforms/pseries/setup.c > b/arch/powerpc/platforms/pseries/setup.c index > b42087cd8c6b..7a9421d089d8 100644 --- > a/arch/powerpc/platforms/pseries/setup.c +++ > b/arch/powerpc/platforms/pseries/setup.c @@ -1000,6 +1000,7 @@ > define_machine(pseries) { .calibrate_decr = > generic_calibrate_decr, .progress = rtas_progress, > .system_reset_exception = pSeries_system_reset_exception, > + .machine_check_early = pSeries_machine_check_realmode, > .machine_check_exception = pSeries_machine_check_exception, > #ifdef CONFIG_KEXEC_CORE > .machine_kexec = pSeries_machine_kexec, > >
On Tue, 07 Aug 2018 19:47:14 +0530 Mahesh J Salgaonkar <mahesh@linux.vnet.ibm.com> wrote: > From: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> > > On pseries, as of today system crashes if we get a machine check > exceptions due to SLB errors. These are soft errors and can be fixed by > flushing the SLBs so the kernel can continue to function instead of > system crash. We do this in real mode before turning on MMU. Otherwise > we would run into nested machine checks. This patch now fetches the > rtas error log in real mode and flushes the SLBs on SLB errors. > > Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> > Signed-off-by: Michal Suchanek <msuchanek@suse.com> > --- > > Changes in V7: > - Fold Michal's patch into this patch. > - Handle MSR_RI=0 and evil context case in MC handler. > --- > diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c > index cb796724a6fc..e89f675f1b5e 100644 > --- a/arch/powerpc/mm/slb.c > +++ b/arch/powerpc/mm/slb.c > @@ -145,6 +145,12 @@ void slb_flush_and_rebolt(void) > get_paca()->slb_cache_ptr = 0; > } > > +void slb_flush_and_rebolt_realmode(void) > +{ > + __slb_flush_and_rebolt(); > + get_paca()->slb_cache_ptr = 0; > +} > + > void slb_vmalloc_update(void) > { > unsigned long vflags; Can you use this patch for the SLB flush? https://patchwork.ozlabs.org/patch/953034/ Thanks, Nick
On 08/07/2018 10:24 PM, Michal Suchánek wrote: > Hello, > > > On Tue, 07 Aug 2018 19:47:14 +0530 > "Mahesh J Salgaonkar" <mahesh@linux.vnet.ibm.com> wrote: > >> From: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> >> >> On pseries, as of today system crashes if we get a machine check >> exceptions due to SLB errors. These are soft errors and can be fixed >> by flushing the SLBs so the kernel can continue to function instead of >> system crash. We do this in real mode before turning on MMU. Otherwise >> we would run into nested machine checks. This patch now fetches the >> rtas error log in real mode and flushes the SLBs on SLB errors. >> >> Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> >> Signed-off-by: Michal Suchanek <msuchanek@suse.com> >> --- >> >> Changes in V7: >> - Fold Michal's patch into this patch. >> - Handle MSR_RI=0 and evil context case in MC handler. >> --- >> arch/powerpc/include/asm/book3s/64/mmu-hash.h | 1 >> arch/powerpc/include/asm/machdep.h | 1 >> arch/powerpc/kernel/exceptions-64s.S | 112 >> +++++++++++++++++++++++++ >> arch/powerpc/kernel/mce.c | 15 +++ >> arch/powerpc/mm/slb.c | 6 + >> arch/powerpc/platforms/powernv/setup.c | 11 ++ >> arch/powerpc/platforms/pseries/pseries.h | 1 >> arch/powerpc/platforms/pseries/ras.c | 51 +++++++++++ >> arch/powerpc/platforms/pseries/setup.c | 1 9 files changed, >> 195 insertions(+), 4 deletions(-) >> >> diff --git a/arch/powerpc/include/asm/book3s/64/mmu-hash.h >> b/arch/powerpc/include/asm/book3s/64/mmu-hash.h index >> 50ed64fba4ae..cc00a7088cf3 100644 --- >> a/arch/powerpc/include/asm/book3s/64/mmu-hash.h +++ >> b/arch/powerpc/include/asm/book3s/64/mmu-hash.h @@ -487,6 +487,7 @@ >> extern void hpte_init_native(void); >> extern void slb_initialize(void); >> extern void slb_flush_and_rebolt(void); >> +extern void slb_flush_and_rebolt_realmode(void); >> >> extern void slb_vmalloc_update(void); >> extern void slb_set_size(u16 size); >> diff --git a/arch/powerpc/include/asm/machdep.h >> b/arch/powerpc/include/asm/machdep.h index a47de82fb8e2..b4831f1338db >> 100644 --- a/arch/powerpc/include/asm/machdep.h >> +++ b/arch/powerpc/include/asm/machdep.h >> @@ -108,6 +108,7 @@ struct machdep_calls { >> >> /* Early exception handlers called in realmode */ >> int (*hmi_exception_early)(struct pt_regs >> *regs); >> + long (*machine_check_early)(struct pt_regs >> *regs); >> /* Called during machine check exception to retrive fixup >> address. */ bool (*mce_check_early_recovery)(struct >> pt_regs *regs); diff --git a/arch/powerpc/kernel/exceptions-64s.S >> b/arch/powerpc/kernel/exceptions-64s.S index >> 285c6465324a..cb06f219570a 100644 --- >> a/arch/powerpc/kernel/exceptions-64s.S +++ >> b/arch/powerpc/kernel/exceptions-64s.S @@ -332,6 +332,9 @@ >> TRAMP_REAL_BEGIN(machine_check_pSeries) machine_check_fwnmi: >> SET_SCRATCH0(r13) /* save r13 */ >> EXCEPTION_PROLOG_0(PACA_EXMC) >> +BEGIN_FTR_SECTION >> + b machine_check_pSeries_early >> +END_FTR_SECTION_IFCLR(CPU_FTR_HVMODE) >> machine_check_pSeries_0: >> EXCEPTION_PROLOG_1(PACA_EXMC, KVMTEST_PR, 0x200) >> /* >> @@ -343,6 +346,90 @@ machine_check_pSeries_0: >> >> TRAMP_KVM_SKIP(PACA_EXMC, 0x200) >> >> +TRAMP_REAL_BEGIN(machine_check_pSeries_early) >> +BEGIN_FTR_SECTION >> + EXCEPTION_PROLOG_1(PACA_EXMC, NOTEST, 0x200) >> + mr r10,r1 /* Save r1 */ >> + ld r1,PACAMCEMERGSP(r13) /* Use MC emergency >> stack */ >> + subi r1,r1,INT_FRAME_SIZE /* alloc stack >> frame */ >> + mfspr r11,SPRN_SRR0 /* Save SRR0 */ >> + mfspr r12,SPRN_SRR1 /* Save SRR1 */ >> + EXCEPTION_PROLOG_COMMON_1() >> + EXCEPTION_PROLOG_COMMON_2(PACA_EXMC) >> + EXCEPTION_PROLOG_COMMON_3(0x200) >> + addi r3,r1,STACK_FRAME_OVERHEAD >> + BRANCH_LINK_TO_FAR(machine_check_early) /* Function call ABI >> */ >> + ld r12,_MSR(r1) >> + andi. r11,r12,MSR_PR /* See if coming >> from user. */ >> + bne 2f /* continue in V mode >> if we are. */ + >> + /* >> + * At this point we are not sure about what context we come >> from. >> + * We may be in the middle of swithing stack. r1 may not be >> valid. >> + * Hence stay on emergency stack, call >> machine_check_exception and >> + * return from the interrupt. >> + * But before that, check if this is an un-recoverable >> exception. >> + * If yes, then stay on emergency stack and panic. >> + */ >> + andi. r11,r12,MSR_RI >> + bne 1f >> + >> + /* >> + * Check if we have successfully handled/recovered from >> error, if not >> + * then stay on emergency stack and panic. >> + */ >> + cmpdi r3,0 /* see if we handled MCE >> successfully */ >> + bne 1f /* if handled then return from >> interrupt */ + >> + LOAD_HANDLER(r10,unrecover_mce) >> + mtspr SPRN_SRR0,r10 >> + ld r10,PACAKMSR(r13) >> + /* >> + * We are going down. But there are chances that we might >> get hit by >> + * another MCE during panic path and we may run into >> unstable state >> + * with no way out. Hence, turn ME bit off while going down, >> so that >> + * when another MCE is hit during panic path, hypervisor will >> + * power cycle the lpar, instead of getting into MCE loop. >> + */ >> + li r3,MSR_ME >> + andc r10,r10,r3 /* Turn off MSR_ME */ >> + mtspr SPRN_SRR1,r10 >> + RFI_TO_KERNEL >> + b . >> + >> + /* Stay on emergency stack and return from interrupt. */ >> +1: LOAD_HANDLER(r10,mce_return) >> + mtspr SPRN_SRR0,r10 >> + ld r10,PACAKMSR(r13) >> + mtspr SPRN_SRR1,r10 >> + RFI_TO_KERNEL >> + b . > > I think that the logic should be inverted here. That is we should check > for unrecoverable and unhandled exceptions and jump to unrecov_mce if > found, fallthrough to mce_return otherwise. sure. will make that change in next revision. Thanks, -Mahesh. > > Thanks > > Michal > > >> + >> + /* Move original SRR0 and SRR1 into the respective regs */ >> +2: ld r9,_MSR(r1) >> + mtspr SPRN_SRR1,r9 >> + ld r3,_NIP(r1) >> + mtspr SPRN_SRR0,r3 >> + ld r9,_CTR(r1) >> + mtctr r9 >> + ld r9,_XER(r1) >> + mtxer r9 >> + ld r9,_LINK(r1) >> + mtlr r9 >> + REST_GPR(0, r1) >> + REST_8GPRS(2, r1) >> + REST_GPR(10, r1) >> + ld r11,_CCR(r1) >> + mtcr r11 >> + REST_GPR(11, r1) >> + REST_2GPRS(12, r1) >> + /* restore original r1. */ >> + ld r1,GPR1(r1) >> + SET_SCRATCH0(r13) /* save r13 */ >> + EXCEPTION_PROLOG_0(PACA_EXMC) >> + b machine_check_pSeries_0 >> +END_FTR_SECTION_IFCLR(CPU_FTR_HVMODE) >> + >> EXC_COMMON_BEGIN(machine_check_common) >> /* >> * Machine check is different because we use a different >> @@ -536,6 +623,31 @@ EXC_COMMON_BEGIN(unrecover_mce) >> bl unrecoverable_exception >> b 1b >> >> +EXC_COMMON_BEGIN(mce_return) >> + /* Invoke machine_check_exception to print MCE event and >> return. */ >> + addi r3,r1,STACK_FRAME_OVERHEAD >> + bl machine_check_exception >> + ld r9,_MSR(r1) >> + mtspr SPRN_SRR1,r9 >> + ld r3,_NIP(r1) >> + mtspr SPRN_SRR0,r3 >> + ld r9,_CTR(r1) >> + mtctr r9 >> + ld r9,_XER(r1) >> + mtxer r9 >> + ld r9,_LINK(r1) >> + mtlr r9 >> + REST_GPR(0, r1) >> + REST_8GPRS(2, r1) >> + REST_GPR(10, r1) >> + ld r11,_CCR(r1) >> + mtcr r11 >> + REST_GPR(11, r1) >> + REST_2GPRS(12, r1) >> + /* restore original r1. */ >> + ld r1,GPR1(r1) >> + RFI_TO_KERNEL >> + b . >> >> EXC_REAL(data_access, 0x300, 0x80) >> EXC_VIRT(data_access, 0x4300, 0x80, 0x300) >> diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c >> index efdd16a79075..ae17d8aa60c4 100644 >> --- a/arch/powerpc/kernel/mce.c >> +++ b/arch/powerpc/kernel/mce.c >> @@ -488,10 +488,19 @@ long machine_check_early(struct pt_regs *regs) >> { >> long handled = 0; >> >> - __this_cpu_inc(irq_stat.mce_exceptions); >> + /* >> + * For pSeries we count mce when we go into virtual mode >> machine >> + * check handler. Hence skip it. Also, We can't access per >> cpu >> + * variables in real mode for LPAR. >> + */ >> + if (early_cpu_has_feature(CPU_FTR_HVMODE)) >> + __this_cpu_inc(irq_stat.mce_exceptions); >> >> - if (cur_cpu_spec && cur_cpu_spec->machine_check_early) >> - handled = cur_cpu_spec->machine_check_early(regs); >> + /* >> + * See if platform is capable of handling machine check. >> + */ >> + if (ppc_md.machine_check_early) >> + handled = ppc_md.machine_check_early(regs); >> return handled; >> } >> >> diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c >> index cb796724a6fc..e89f675f1b5e 100644 >> --- a/arch/powerpc/mm/slb.c >> +++ b/arch/powerpc/mm/slb.c >> @@ -145,6 +145,12 @@ void slb_flush_and_rebolt(void) >> get_paca()->slb_cache_ptr = 0; >> } >> >> +void slb_flush_and_rebolt_realmode(void) >> +{ >> + __slb_flush_and_rebolt(); >> + get_paca()->slb_cache_ptr = 0; >> +} >> + >> void slb_vmalloc_update(void) >> { >> unsigned long vflags; >> diff --git a/arch/powerpc/platforms/powernv/setup.c >> b/arch/powerpc/platforms/powernv/setup.c index >> f96df0a25d05..b74c93bc2e55 100644 --- >> a/arch/powerpc/platforms/powernv/setup.c +++ >> b/arch/powerpc/platforms/powernv/setup.c @@ -431,6 +431,16 @@ static >> unsigned long pnv_get_proc_freq(unsigned int cpu) return ret_freq; >> } >> >> +static long pnv_machine_check_early(struct pt_regs *regs) >> +{ >> + long handled = 0; >> + >> + if (cur_cpu_spec && cur_cpu_spec->machine_check_early) >> + handled = cur_cpu_spec->machine_check_early(regs); >> + >> + return handled; >> +} >> + >> define_machine(powernv) { >> .name = "PowerNV", >> .probe = pnv_probe, >> @@ -442,6 +452,7 @@ define_machine(powernv) { >> .machine_shutdown = pnv_shutdown, >> .power_save = NULL, >> .calibrate_decr = generic_calibrate_decr, >> + .machine_check_early = pnv_machine_check_early, >> #ifdef CONFIG_KEXEC_CORE >> .kexec_cpu_down = pnv_kexec_cpu_down, >> #endif >> diff --git a/arch/powerpc/platforms/pseries/pseries.h >> b/arch/powerpc/platforms/pseries/pseries.h index >> 60db2ee511fb..ec2a5f61d4a4 100644 --- >> a/arch/powerpc/platforms/pseries/pseries.h +++ >> b/arch/powerpc/platforms/pseries/pseries.h @@ -24,6 +24,7 @@ struct >> pt_regs; >> extern int pSeries_system_reset_exception(struct pt_regs *regs); >> extern int pSeries_machine_check_exception(struct pt_regs *regs); >> +extern long pSeries_machine_check_realmode(struct pt_regs *regs); >> >> #ifdef CONFIG_SMP >> extern void smp_init_pseries(void); >> diff --git a/arch/powerpc/platforms/pseries/ras.c >> b/arch/powerpc/platforms/pseries/ras.c index >> 851ce326874a..e4420f7c8fda 100644 --- >> a/arch/powerpc/platforms/pseries/ras.c +++ >> b/arch/powerpc/platforms/pseries/ras.c @@ -427,6 +427,35 @@ int >> pSeries_system_reset_exception(struct pt_regs *regs) return 0; /* >> need to perform reset */ } >> >> +static int mce_handle_error(struct rtas_error_log *errp) >> +{ >> + struct pseries_errorlog *pseries_log; >> + struct pseries_mc_errorlog *mce_log; >> + int disposition = rtas_error_disposition(errp); >> + uint8_t error_type; >> + >> + if (!rtas_error_extended(errp)) >> + goto out; >> + >> + pseries_log = get_pseries_errorlog(errp, >> PSERIES_ELOG_SECT_ID_MCE); >> + if (pseries_log == NULL) >> + goto out; >> + >> + mce_log = (struct pseries_mc_errorlog *)pseries_log->data; >> + error_type = rtas_mc_error_type(mce_log); >> + >> + if ((disposition == RTAS_DISP_NOT_RECOVERED) && >> + (error_type == PSERIES_MC_ERROR_TYPE_SLB)) { >> + /* Store the old slb content someplace. */ >> + slb_flush_and_rebolt_realmode(); >> + disposition = RTAS_DISP_FULLY_RECOVERED; >> + rtas_set_disposition_recovered(errp); >> + } >> + >> +out: >> + return disposition; >> +} >> + >> /* >> * Process MCE rtas errlog event. >> */ >> @@ -503,11 +532,31 @@ int pSeries_machine_check_exception(struct >> pt_regs *regs) struct rtas_error_log *errp; >> >> if (fwnmi_active) { >> - errp = fwnmi_get_errinfo(regs); >> fwnmi_release_errinfo(); >> + errp = fwnmi_get_errlog(); >> if (errp && recover_mce(regs, errp)) >> return 1; >> } >> >> return 0; >> } >> + >> +long pSeries_machine_check_realmode(struct pt_regs *regs) >> +{ >> + struct rtas_error_log *errp; >> + int disposition; >> + >> + if (fwnmi_active) { >> + errp = fwnmi_get_errinfo(regs); >> + /* >> + * Call to fwnmi_release_errinfo() in real mode >> causes kernel >> + * to panic. Hence we will call it as soon as we go >> into >> + * virtual mode. >> + */ >> + disposition = mce_handle_error(errp); >> + if (disposition == RTAS_DISP_FULLY_RECOVERED) >> + return 1; >> + } >> + >> + return 0; >> +} >> diff --git a/arch/powerpc/platforms/pseries/setup.c >> b/arch/powerpc/platforms/pseries/setup.c index >> b42087cd8c6b..7a9421d089d8 100644 --- >> a/arch/powerpc/platforms/pseries/setup.c +++ >> b/arch/powerpc/platforms/pseries/setup.c @@ -1000,6 +1000,7 @@ >> define_machine(pseries) { .calibrate_decr = >> generic_calibrate_decr, .progress = rtas_progress, >> .system_reset_exception = pSeries_system_reset_exception, >> + .machine_check_early = pSeries_machine_check_realmode, >> .machine_check_exception = pSeries_machine_check_exception, >> #ifdef CONFIG_KEXEC_CORE >> .machine_kexec = pSeries_machine_kexec, >> >> >
On 08/08/2018 02:34 PM, Nicholas Piggin wrote: > On Tue, 07 Aug 2018 19:47:14 +0530 > Mahesh J Salgaonkar <mahesh@linux.vnet.ibm.com> wrote: > >> From: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> >> >> On pseries, as of today system crashes if we get a machine check >> exceptions due to SLB errors. These are soft errors and can be fixed by >> flushing the SLBs so the kernel can continue to function instead of >> system crash. We do this in real mode before turning on MMU. Otherwise >> we would run into nested machine checks. This patch now fetches the >> rtas error log in real mode and flushes the SLBs on SLB errors. >> >> Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> >> Signed-off-by: Michal Suchanek <msuchanek@suse.com> >> --- >> >> Changes in V7: >> - Fold Michal's patch into this patch. >> - Handle MSR_RI=0 and evil context case in MC handler. >> --- > > >> diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c >> index cb796724a6fc..e89f675f1b5e 100644 >> --- a/arch/powerpc/mm/slb.c >> +++ b/arch/powerpc/mm/slb.c >> @@ -145,6 +145,12 @@ void slb_flush_and_rebolt(void) >> get_paca()->slb_cache_ptr = 0; >> } >> >> +void slb_flush_and_rebolt_realmode(void) >> +{ >> + __slb_flush_and_rebolt(); >> + get_paca()->slb_cache_ptr = 0; >> +} >> + >> void slb_vmalloc_update(void) >> { >> unsigned long vflags; > > Can you use this patch for the SLB flush? > > https://patchwork.ozlabs.org/patch/953034/ Will use your v2. Thanks, -Mahesh. > > Thanks, > Nick >
diff --git a/arch/powerpc/include/asm/book3s/64/mmu-hash.h b/arch/powerpc/include/asm/book3s/64/mmu-hash.h index 50ed64fba4ae..cc00a7088cf3 100644 --- a/arch/powerpc/include/asm/book3s/64/mmu-hash.h +++ b/arch/powerpc/include/asm/book3s/64/mmu-hash.h @@ -487,6 +487,7 @@ extern void hpte_init_native(void); extern void slb_initialize(void); extern void slb_flush_and_rebolt(void); +extern void slb_flush_and_rebolt_realmode(void); extern void slb_vmalloc_update(void); extern void slb_set_size(u16 size); diff --git a/arch/powerpc/include/asm/machdep.h b/arch/powerpc/include/asm/machdep.h index a47de82fb8e2..b4831f1338db 100644 --- a/arch/powerpc/include/asm/machdep.h +++ b/arch/powerpc/include/asm/machdep.h @@ -108,6 +108,7 @@ struct machdep_calls { /* Early exception handlers called in realmode */ int (*hmi_exception_early)(struct pt_regs *regs); + long (*machine_check_early)(struct pt_regs *regs); /* Called during machine check exception to retrive fixup address. */ bool (*mce_check_early_recovery)(struct pt_regs *regs); diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index 285c6465324a..cb06f219570a 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -332,6 +332,9 @@ TRAMP_REAL_BEGIN(machine_check_pSeries) machine_check_fwnmi: SET_SCRATCH0(r13) /* save r13 */ EXCEPTION_PROLOG_0(PACA_EXMC) +BEGIN_FTR_SECTION + b machine_check_pSeries_early +END_FTR_SECTION_IFCLR(CPU_FTR_HVMODE) machine_check_pSeries_0: EXCEPTION_PROLOG_1(PACA_EXMC, KVMTEST_PR, 0x200) /* @@ -343,6 +346,90 @@ machine_check_pSeries_0: TRAMP_KVM_SKIP(PACA_EXMC, 0x200) +TRAMP_REAL_BEGIN(machine_check_pSeries_early) +BEGIN_FTR_SECTION + EXCEPTION_PROLOG_1(PACA_EXMC, NOTEST, 0x200) + mr r10,r1 /* Save r1 */ + ld r1,PACAMCEMERGSP(r13) /* Use MC emergency stack */ + subi r1,r1,INT_FRAME_SIZE /* alloc stack frame */ + mfspr r11,SPRN_SRR0 /* Save SRR0 */ + mfspr r12,SPRN_SRR1 /* Save SRR1 */ + EXCEPTION_PROLOG_COMMON_1() + EXCEPTION_PROLOG_COMMON_2(PACA_EXMC) + EXCEPTION_PROLOG_COMMON_3(0x200) + addi r3,r1,STACK_FRAME_OVERHEAD + BRANCH_LINK_TO_FAR(machine_check_early) /* Function call ABI */ + ld r12,_MSR(r1) + andi. r11,r12,MSR_PR /* See if coming from user. */ + bne 2f /* continue in V mode if we are. */ + + /* + * At this point we are not sure about what context we come from. + * We may be in the middle of swithing stack. r1 may not be valid. + * Hence stay on emergency stack, call machine_check_exception and + * return from the interrupt. + * But before that, check if this is an un-recoverable exception. + * If yes, then stay on emergency stack and panic. + */ + andi. r11,r12,MSR_RI + bne 1f + + /* + * Check if we have successfully handled/recovered from error, if not + * then stay on emergency stack and panic. + */ + cmpdi r3,0 /* see if we handled MCE successfully */ + bne 1f /* if handled then return from interrupt */ + + LOAD_HANDLER(r10,unrecover_mce) + mtspr SPRN_SRR0,r10 + ld r10,PACAKMSR(r13) + /* + * We are going down. But there are chances that we might get hit by + * another MCE during panic path and we may run into unstable state + * with no way out. Hence, turn ME bit off while going down, so that + * when another MCE is hit during panic path, hypervisor will + * power cycle the lpar, instead of getting into MCE loop. + */ + li r3,MSR_ME + andc r10,r10,r3 /* Turn off MSR_ME */ + mtspr SPRN_SRR1,r10 + RFI_TO_KERNEL + b . + + /* Stay on emergency stack and return from interrupt. */ +1: LOAD_HANDLER(r10,mce_return) + mtspr SPRN_SRR0,r10 + ld r10,PACAKMSR(r13) + mtspr SPRN_SRR1,r10 + RFI_TO_KERNEL + b . + + /* Move original SRR0 and SRR1 into the respective regs */ +2: ld r9,_MSR(r1) + mtspr SPRN_SRR1,r9 + ld r3,_NIP(r1) + mtspr SPRN_SRR0,r3 + ld r9,_CTR(r1) + mtctr r9 + ld r9,_XER(r1) + mtxer r9 + ld r9,_LINK(r1) + mtlr r9 + REST_GPR(0, r1) + REST_8GPRS(2, r1) + REST_GPR(10, r1) + ld r11,_CCR(r1) + mtcr r11 + REST_GPR(11, r1) + REST_2GPRS(12, r1) + /* restore original r1. */ + ld r1,GPR1(r1) + SET_SCRATCH0(r13) /* save r13 */ + EXCEPTION_PROLOG_0(PACA_EXMC) + b machine_check_pSeries_0 +END_FTR_SECTION_IFCLR(CPU_FTR_HVMODE) + EXC_COMMON_BEGIN(machine_check_common) /* * Machine check is different because we use a different @@ -536,6 +623,31 @@ EXC_COMMON_BEGIN(unrecover_mce) bl unrecoverable_exception b 1b +EXC_COMMON_BEGIN(mce_return) + /* Invoke machine_check_exception to print MCE event and return. */ + addi r3,r1,STACK_FRAME_OVERHEAD + bl machine_check_exception + ld r9,_MSR(r1) + mtspr SPRN_SRR1,r9 + ld r3,_NIP(r1) + mtspr SPRN_SRR0,r3 + ld r9,_CTR(r1) + mtctr r9 + ld r9,_XER(r1) + mtxer r9 + ld r9,_LINK(r1) + mtlr r9 + REST_GPR(0, r1) + REST_8GPRS(2, r1) + REST_GPR(10, r1) + ld r11,_CCR(r1) + mtcr r11 + REST_GPR(11, r1) + REST_2GPRS(12, r1) + /* restore original r1. */ + ld r1,GPR1(r1) + RFI_TO_KERNEL + b . EXC_REAL(data_access, 0x300, 0x80) EXC_VIRT(data_access, 0x4300, 0x80, 0x300) diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c index efdd16a79075..ae17d8aa60c4 100644 --- a/arch/powerpc/kernel/mce.c +++ b/arch/powerpc/kernel/mce.c @@ -488,10 +488,19 @@ long machine_check_early(struct pt_regs *regs) { long handled = 0; - __this_cpu_inc(irq_stat.mce_exceptions); + /* + * For pSeries we count mce when we go into virtual mode machine + * check handler. Hence skip it. Also, We can't access per cpu + * variables in real mode for LPAR. + */ + if (early_cpu_has_feature(CPU_FTR_HVMODE)) + __this_cpu_inc(irq_stat.mce_exceptions); - if (cur_cpu_spec && cur_cpu_spec->machine_check_early) - handled = cur_cpu_spec->machine_check_early(regs); + /* + * See if platform is capable of handling machine check. + */ + if (ppc_md.machine_check_early) + handled = ppc_md.machine_check_early(regs); return handled; } diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c index cb796724a6fc..e89f675f1b5e 100644 --- a/arch/powerpc/mm/slb.c +++ b/arch/powerpc/mm/slb.c @@ -145,6 +145,12 @@ void slb_flush_and_rebolt(void) get_paca()->slb_cache_ptr = 0; } +void slb_flush_and_rebolt_realmode(void) +{ + __slb_flush_and_rebolt(); + get_paca()->slb_cache_ptr = 0; +} + void slb_vmalloc_update(void) { unsigned long vflags; diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c index f96df0a25d05..b74c93bc2e55 100644 --- a/arch/powerpc/platforms/powernv/setup.c +++ b/arch/powerpc/platforms/powernv/setup.c @@ -431,6 +431,16 @@ static unsigned long pnv_get_proc_freq(unsigned int cpu) return ret_freq; } +static long pnv_machine_check_early(struct pt_regs *regs) +{ + long handled = 0; + + if (cur_cpu_spec && cur_cpu_spec->machine_check_early) + handled = cur_cpu_spec->machine_check_early(regs); + + return handled; +} + define_machine(powernv) { .name = "PowerNV", .probe = pnv_probe, @@ -442,6 +452,7 @@ define_machine(powernv) { .machine_shutdown = pnv_shutdown, .power_save = NULL, .calibrate_decr = generic_calibrate_decr, + .machine_check_early = pnv_machine_check_early, #ifdef CONFIG_KEXEC_CORE .kexec_cpu_down = pnv_kexec_cpu_down, #endif diff --git a/arch/powerpc/platforms/pseries/pseries.h b/arch/powerpc/platforms/pseries/pseries.h index 60db2ee511fb..ec2a5f61d4a4 100644 --- a/arch/powerpc/platforms/pseries/pseries.h +++ b/arch/powerpc/platforms/pseries/pseries.h @@ -24,6 +24,7 @@ struct pt_regs; extern int pSeries_system_reset_exception(struct pt_regs *regs); extern int pSeries_machine_check_exception(struct pt_regs *regs); +extern long pSeries_machine_check_realmode(struct pt_regs *regs); #ifdef CONFIG_SMP extern void smp_init_pseries(void); diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c index 851ce326874a..e4420f7c8fda 100644 --- a/arch/powerpc/platforms/pseries/ras.c +++ b/arch/powerpc/platforms/pseries/ras.c @@ -427,6 +427,35 @@ int pSeries_system_reset_exception(struct pt_regs *regs) return 0; /* need to perform reset */ } +static int mce_handle_error(struct rtas_error_log *errp) +{ + struct pseries_errorlog *pseries_log; + struct pseries_mc_errorlog *mce_log; + int disposition = rtas_error_disposition(errp); + uint8_t error_type; + + if (!rtas_error_extended(errp)) + goto out; + + pseries_log = get_pseries_errorlog(errp, PSERIES_ELOG_SECT_ID_MCE); + if (pseries_log == NULL) + goto out; + + mce_log = (struct pseries_mc_errorlog *)pseries_log->data; + error_type = rtas_mc_error_type(mce_log); + + if ((disposition == RTAS_DISP_NOT_RECOVERED) && + (error_type == PSERIES_MC_ERROR_TYPE_SLB)) { + /* Store the old slb content someplace. */ + slb_flush_and_rebolt_realmode(); + disposition = RTAS_DISP_FULLY_RECOVERED; + rtas_set_disposition_recovered(errp); + } + +out: + return disposition; +} + /* * Process MCE rtas errlog event. */ @@ -503,11 +532,31 @@ int pSeries_machine_check_exception(struct pt_regs *regs) struct rtas_error_log *errp; if (fwnmi_active) { - errp = fwnmi_get_errinfo(regs); fwnmi_release_errinfo(); + errp = fwnmi_get_errlog(); if (errp && recover_mce(regs, errp)) return 1; } return 0; } + +long pSeries_machine_check_realmode(struct pt_regs *regs) +{ + struct rtas_error_log *errp; + int disposition; + + if (fwnmi_active) { + errp = fwnmi_get_errinfo(regs); + /* + * Call to fwnmi_release_errinfo() in real mode causes kernel + * to panic. Hence we will call it as soon as we go into + * virtual mode. + */ + disposition = mce_handle_error(errp); + if (disposition == RTAS_DISP_FULLY_RECOVERED) + return 1; + } + + return 0; +} diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c index b42087cd8c6b..7a9421d089d8 100644 --- a/arch/powerpc/platforms/pseries/setup.c +++ b/arch/powerpc/platforms/pseries/setup.c @@ -1000,6 +1000,7 @@ define_machine(pseries) { .calibrate_decr = generic_calibrate_decr, .progress = rtas_progress, .system_reset_exception = pSeries_system_reset_exception, + .machine_check_early = pSeries_machine_check_realmode, .machine_check_exception = pSeries_machine_check_exception, #ifdef CONFIG_KEXEC_CORE .machine_kexec = pSeries_machine_kexec,