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2019-05-01powerpc/powernv/mce: Print additional information about MCE error.Mahesh Salgaonkar
Print more information about MCE error whether it is an hardware or software error. Some of the MCE errors can be easily categorized as hardware or software errors e.g. UEs are due to hardware error, where as error triggered due to invalid usage of tlbie is a pure software bug. But not all the MCE errors can be easily categorize into either software or hardware. There are errors like multihit errors which are usually result of a software bug, but in some rare cases a hardware failure can cause a multihit error. In past, we have seen case where after replacing faulty chip, multihit errors stopped occurring. Same with parity errors, which are usually due to faulty hardware but there are chances where multihit can also cause an parity error. Such errors are difficult to determine what really caused it. Hence this patch classifies MCE errors into following four categorize: 1. Hardware error: UE and Link timeout failure errors. 2. Probable hardware error (some chance of software cause) SLB/ERAT/TLB Parity errors. 3. Software error Invalid tlbie form. 4. Probable software error (some chance of hardware cause) SLB/ERAT/TLB Multihit errors. Sample output: MCE: CPU80: machine check (Warning) Guest SLB Multihit DAR: 000001001b6e0320 [Recovered] MCE: CPU80: PID: 24765 Comm: qemu-system-ppc Guest NIP: [00007fffa309dc60] MCE: CPU80: Probable Software error (some chance of hardware cause) Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-05-01powerpc/powernv/mce: Print correct severity for MCE error.Mahesh Salgaonkar
Currently all machine check errors are printed as severe errors which isn't correct. Print soft errors as warning instead of severe errors. Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-04-20powerpc/pseries: hwpoison the pages upon hitting UEGanesh Goudar
Add support to hwpoison the pages upon hitting machine check exception. This patch queues the address where UE is hit to percpu array and schedules work to plumb it into memory poison infrastructure. Reviewed-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com> [mpe: Combine #ifdefs, drop PPC_BIT8(), and empty inline stub] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-10-04powerpc/64s/hash: Do not use PPC_INVALIDATE_ERAT on CPUs before POWER9Nicholas Piggin
PPC_INVALIDATE_ERAT is slbia IH=7 which is a new variant introduced with POWER9, and the result is undefined on earlier CPUs. Commits 7b9f71f974 ("powerpc/64s: POWER9 machine check handler") and d4748276ae ("powerpc/64s: Improve local TLB flush for boot and MCE on POWER9") caused POWER7/8 code to use this instruction. Remove it. An ERAT flush can be made by invalidatig the SLB, but before POWER9 that requires a flush and rebolt. Fixes: 7b9f71f974 ("powerpc/64s: POWER9 machine check handler") Fixes: d4748276ae ("powerpc/64s: Improve local TLB flush for boot and MCE on POWER9") Cc: stable@vger.kernel.org # v4.11+ Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-09-19powerpc/pseries: Flush SLB contents on SLB MCE errors.Mahesh Salgaonkar
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/ERAT errors. Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Michal Suchanek <msuchanek@suse.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-08-10powerpc/64s: move machine check SLB flushing to mm/slb.cNicholas Piggin
The machine check code that flushes and restores bolted segments in real mode belongs in mm/slb.c. This will also be used by pseries machine check and idle code in future changes. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-07-12powerpc/64s: Report SLB multi-hit rather than parity errorMichael Ellerman
When we take an SLB multi-hit on bare metal, we see both the multi-hit and parity error bits set in DSISR. The user manuals indicates this is expected to always happen on Power8, whereas on Power9 it says a multi-hit will "usually" also cause a parity error. We decide what to do based on the various error tables in mce_power.c, and because we process them in order and only report the first, we currently always report a parity error but not the multi-hit, eg: Severe Machine check interrupt [Recovered] Initiator: CPU Error type: SLB [Parity] Effective address: c000000ffffd4300 Although this is correct, it leaves the user wondering why they got a parity error. It would be clearer instead if we reported the multi-hit because that is more likely to be simply a software bug, whereas a true parity error is possibly an indication of a bad core. We can do that simply by reordering the error tables so that multi-hit appears before parity. That doesn't affect the error recovery at all, because we flush the SLB either way. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-04-24powerpc/mce: Fix a bug where mce loops on memory UE.Mahesh Salgaonkar
The current code extracts the physical address for UE errors and then hooks it up into memory failure infrastructure. On successful extraction of physical address it wrongly sets "handled = 1" which means this UE error has been recovered. Since MCE handler gets return value as handled = 1, it assumes that error has been recovered and goes back to same NIP. This causes MCE interrupt again and again in a loop leading to hard lockup. Also, initialize phys_addr to ULONG_MAX so that we don't end up queuing undesired page to hwpoison. Without this patch we see: Severe Machine check interrupt [Recovered] NIP: [000000001002588c] PID: 7109 Comm: find Initiator: CPU Error type: UE [Load/Store] Effective address: 00007fffd2755940 Physical address: 000020181a080000 ... Severe Machine check interrupt [Recovered] NIP: [000000001002588c] PID: 7109 Comm: find Initiator: CPU Error type: UE [Load/Store] Effective address: 00007fffd2755940 Physical address: 000020181a080000 Severe Machine check interrupt [Recovered] NIP: [000000001002588c] PID: 7109 Comm: find Initiator: CPU Error type: UE [Load/Store] Effective address: 00007fffd2755940 Physical address: 000020181a080000 Memory failure: 0x20181a08: recovery action for dirty LRU page: Recovered Memory failure: 0x20181a08: already hardware poisoned Memory failure: 0x20181a08: already hardware poisoned Memory failure: 0x20181a08: already hardware poisoned Memory failure: 0x20181a08: already hardware poisoned Memory failure: 0x20181a08: already hardware poisoned Memory failure: 0x20181a08: already hardware poisoned ... Watchdog CPU:38 Hard LOCKUP After this patch we see: Severe Machine check interrupt [Not recovered] NIP: [00007fffaae585f4] PID: 7168 Comm: find Initiator: CPU Error type: UE [Load/Store] Effective address: 00007fffaafe28ac Physical address: 00002017c0bd0000 find[7168]: unhandled signal 7 at 00007fffaae585f4 nip 00007fffaae585f4 lr 00007fffaae585e0 code 4 Memory failure: 0x2017c0bd: recovery action for dirty LRU page: Recovered Fixes: 01eaac2b0591 ("powerpc/mce: Hookup ierror (instruction) UE errors") Fixes: ba41e1e1ccb9 ("powerpc/mce: Hookup derror (load/store) UE errors") Cc: stable@vger.kernel.org # v4.15+ Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Balbir Singh <bsingharora@gmail.com> Reviewed-by: Balbir Singh <bsingharora@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-01-18powerpc/64s: Improve local TLB flush for boot and MCE on POWER9Nicholas Piggin
There are several cases outside the normal address space management where a CPU's entire local TLB is to be flushed: 1. Booting the kernel, in case something has left stale entries in the TLB (e.g., kexec). 2. Machine check, to clean corrupted TLB entries. One other place where the TLB is flushed, is waking from deep idle states. The flush is a side-effect of calling ->cpu_restore with the intention of re-setting various SPRs. The flush itself is unnecessary because in the first case, the TLB should not acquire new corrupted TLB entries as part of sleep/wake (though they may be lost). This type of TLB flush is coded inflexibly, several times for each CPU type, and they have a number of problems with ISA v3.0B: - The current radix mode of the MMU is not taken into account, it is always done as a hash flushn For IS=2 (LPID-matching flush from host) and IS=3 with HV=0 (guest kernel flush), tlbie(l) is undefined if the R field does not match the current radix mode. - ISA v3.0B hash must flush the partition and process table caches as well. - ISA v3.0B radix must flush partition and process scoped translations, partition and process table caches, and also the page walk cache. So consolidate the flushing code and implement it in C and inline asm under the mm/ directory with the rest of the flush code. Add ISA v3.0B cases for radix and hash, and use the radix flush in radix environment. Provide a way for IS=2 (LPID flush) to specify the radix mode of the partition. Have KVM pass in the radix mode of the guest. Take out the flushes from early cputable/dt_cpu_ftrs detection hooks, and move it later in the boot process after, the MMU registers are set up and before relocation is first turned on. The TLB flush is no longer called when restoring from deep idle states. This was not be done as a separate step because booting secondaries uses the same cpu_restore as idle restore, which needs the TLB flush. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-11-10Merge branch 'fixes' into nextMichael Ellerman
We have some dependencies & conflicts between patches in fixes and things to go in next, both in the radix TLB flush code and the IMC PMU driver. So merge fixes into next.
2017-11-06powerpc/64s: Replace CONFIG_PPC_STD_MMU_64 with CONFIG_PPC_BOOK3S_64Michael Ellerman
CONFIG_PPC_STD_MMU_64 indicates support for the "standard" powerpc MMU on 64-bit CPUs. The "standard" MMU refers to the hash page table MMU found in "server" processors, from IBM mainly. Currently CONFIG_PPC_STD_MMU_64 is == CONFIG_PPC_BOOK3S_64. While it's annoying to have two symbols that always have the same value, it's not quite annoying enough to bother removing one. However with the arrival of Power9, we now have the situation where CONFIG_PPC_STD_MMU_64 is enabled, but the kernel is running using the Radix MMU - *not* the "standard" MMU. So it is now actively confusing to use it, because it implies that code is disabled or inactive when the Radix MMU is in use, however that is not necessarily true. So s/CONFIG_PPC_STD_MMU_64/CONFIG_PPC_BOOK3S_64/, and do some minor formatting updates of some of the affected lines. This will be a pain for backports, but c'est la vie. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-10-16powerpc/mce: Hookup ierror (instruction) UE errorsBalbir Singh
Hookup instruction errors (UE) for memory offling via memory_failure() in a manner similar to load/store errors (derror). Since we have access to the NIP, the conversion is a one step process in this case. Signed-off-by: Balbir Singh <bsingharora@gmail.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-10-16powerpc/mce: Hookup derror (load/store) UE errorsBalbir Singh
Extract physical_address for UE errors by walking the page tables for the mm and address at the NIP, to extract the instruction. Then use the instruction to find the effective address via analyse_instr(). We might have page table walking races, but we expect them to be rare, the physical address extraction is best effort. The idea is to then hook up this infrastructure to memory failure eventually. Signed-off-by: Balbir Singh <bsingharora@gmail.com> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-10-04powerpc/powernv: Use early_radix_enabled in POWER9 tlb flushNicholas Piggin
This code is used at boot and machine checks, so it should be using early_radix_enabled() (which is usable any time). Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-29powerpc: Fix workaround for spurious MCE on POWER9Michael Neuling
In the recent commit d8bd9f3f0925 ("powerpc: Handle MCE on POWER9 with only DSISR bit 30 set") I screwed up the bit number. It should be bit 25 (IBM bit 38). Fixes: d8bd9f3f0925 ("powerpc: Handle MCE on POWER9 with only DSISR bit 30 set") Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-09-26powerpc: Handle MCE on POWER9 with only DSISR bit 30 setMichael Neuling
On POWER9 DD2.1 and below, it's possible for a paste instruction to cause a Machine Check Exception (MCE) where only DSISR bit 30 (IBM 33) is set. This will result in the MCE handler seeing an unknown event, which triggers linux to crash. We change this by detecting unknown events caused by load/stores in the MCE handler and marking them as handled so that we no longer crash. An MCE that occurs like this is spurious, so we don't need to do anything in terms of servicing it. If there is something that needs to be serviced, the CPU will raise the MCE again with the correct DSISR so that it can be serviced properly. Signed-off-by: Michael Neuling <mikey@neuling.org> Reviewed-by: Nicholas Piggin <npiggin@gmail.com Acked-by: Balbir Singh <bsingharora@gmail.com> [mpe: Expand comment with details from change log, use normal bit #s] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-11powerpc/powernv: Fix local TLB flush for boot and MCE on POWER9Nicholas Piggin
There are two cases outside the normal address space management where a CPU's local TLB is to be flushed: 1. Host boot; in case something has left stale entries in the TLB (e.g., kexec). 2. Machine check; to clean corrupted TLB entries. CPU state restore from deep idle states also flushes the TLB. However this seems to be a side effect of reusing the boot code to set CPU state, rather than a requirement itself. The current flushing has a number of problems with ISA v3.0B: - The current radix mode of the MMU is not taken into account. tlbiel is undefined if the R field does not match the current radix mode. - ISA v3.0B hash must flush the partition and process table caches. - ISA v3.0B radix must flush partition and process scoped translations, partition and process table caches, and also the page walk cache. Add POWER9 cases to handle these, with radix vs hash determined by the host MMU mode. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-06-06powerpc/64s: Machine check handle ifetch from foreign real address for POWER9Nicholas Piggin
The i-side 0111b machine check, which is "Instruction Fetch to foreign address space", was missed by 7b9f71f974 ("powerpc/64s: POWER9 machine check handler"). The POWER9 processor core considers host real addresses with a nonzero value in RA(8:12) as foreign address space, accessible only by the copy and paste instructions. The copy and paste instruction pair can be used to invoke the Nest accelerators via the Virtual Accelerator Switchboard (VAS). It is an error for any regular load/store or ifetch to go to a foreign addresses. When relocation is on, this causes an MMU exception. When relocation is off, a machine check exception. It is possible to trigger this machine check by branching to a foreign address with MSR[IR]=0. Fixes: 7b9f71f974a1 ("powerpc/64s: POWER9 machine check handler") Reported-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-04-19powerpc/64s: Minor fix for MCE TLB flush for radixNicholas Piggin
The TLB flush for radix first flushes TLB for radix configuration, then flushes for hash configuration. The second flush is unnecessary but does not affect correctness. Fixes: 1a472c9dba6b9 ("powerpc/mm/radix: Add tlbflush routines") Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-03-21powerpc/64s: POWER8 add missing machine check definitionsNicholas Piggin
POWER8 uses bit 36 in SRR1 like POWER9 for i-side machine checks, and contains several conditions for link timeouts that are not currently handled. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-03-21powerpc/64s: Data driven machine check handlingNicholas Piggin
Move the handling (corrective action) of machine checks to the table based evaluation. This changes P7 and P8 ERAT flushing from using SLB flush to using ERAT flush. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-03-21powerpc/64s: Data driven machine check evaluationNicholas Piggin
Have machine types define i-side and d-side tables to describe their machine check encodings, and match entries to evaluate (for reporting) machine checks. Functionality is mostly unchanged (tested with a userspace harness), but it does make a change in that it no longer records DAR as the effective address for those errors where it is specified to be invalid (which is a reporting change only). Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-03-21powerpc/64s: Move POWER machine check defines into mce_power.cNicholas Piggin
Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-03-21powerpc/64s: Clean up machine check recovery flushingNicholas Piggin
Use the flush function introduced with the POWER9 machine check handler for POWER7 and 8, rather than open coding it multiple times in callers. There is a specific ERAT flush type introduced for POWER9, but the POWER7-8 ERAT errors continue to do SLB flushing (which also flushes ERAT), so as not to introduce functional changes with this cleanup patch. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-03-10powerpc/64s: POWER9 machine check handlerNicholas Piggin
Add POWER9 machine check handler. There are several new types of errors added, so logging messages for those are also added. This doesn't attempt to reuse any of the P7/8 defines or functions, because that becomes too complex. The better option in future is to use a table driven approach. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-03-10powerpc/64s: allow machine check handler to set severity and initiatorNicholas Piggin
Currently severity and initiator are always set to MCE_SEV_ERROR_SYNC and MCE_INITIATOR_CPU in the core mce code. Allow them to be set by the machine specific mce handlers. No functional change for existing handlers. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-05-11powerpc/mm/radix: Fix CONFIG_PPC_MMU_STD_64 typoValentin Rothberg
It's CONFIG_PPC_STD_MMU_64 not ... CONFIG_PPC_MMU_STD_64. Fixes: 11ffc1cfa4c2 ("powerpc/mm/radix: Use STD_MMU_64 to properly isolate hash related code") Signed-off-by: Valentin Rothberg <valentinrothberg@gmail.com> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-05-11powerpc/mm/radix: Use STD_MMU_64 to properly isolate hash related codeAneesh Kumar K.V
We also use MMU_FTR_RADIX to branch out from code path specific to hash. No functionality change. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-05-01powerpc/mm/radix: Add tlbflush routinesAneesh Kumar K.V
Core kernel doesn't track the page size of the VA range that we are invalidating. Hence we end up flushing TLB for the entire mm here. Later patches will improve this. We also don't flush page walk cache separetly instead use RIC=2 when flushing TLB, because we do a MMU gather flush after freeing page table. MMU_NO_CONTEXT is updated for hash. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-02-22powerpc: Add POWER9 cputable entryMichael Neuling
Add a cputable entry for POWER9. More code is required to actually boot and run on a POWER9 but this gets the base piece in which we can start building on. Copies over from POWER8 except for: - Adds a new CPU_FTR_ARCH_300 bit to start hanging new architecture features from (in subsequent patches). - Advertises new user features bits PPC_FEATURE2_ARCH_3_00 & HAS_IEEE128 when on POWER9. - Drops CPU_FTR_SUBCORE. - Drops PMU code and machine check. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-03-17powerpc/book3s: Fix flush_tlb cpu_spec hook to take a generic argument.Mahesh Salgaonkar
The flush_tlb hook in cpu_spec was introduced as a generic function hook to invalidate TLBs. But the current implementation of flush_tlb hook takes IS (invalidation selector) as an argument which is architecture dependent. Hence, It is not right to have a generic routine where caller has to pass non-generic argument. This patch fixes this and makes flush_tlb hook as high level API. Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-12-05powerpc/book3s: Fix partial invalidation of TLBs in MCE code.Mahesh Salgaonkar
The existing MCE code calls flush_tlb hook with IS=0 (single page) resulting in partial invalidation of TLBs which is not right. This patch fixes that by passing IS=0xc00 to invalidate whole TLB for successful recovery from TLB and ERAT errors. Cc: stable@vger.kernel.org Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-03-07powerpc/book3s: Recover from MC in sapphire on SCOM read via MMIO.Mahesh Salgaonkar
Detect and recover from machine check when inside opal on a special scom load instructions. On specific SCOM read via MMIO we may get a machine check exception with SRR0 pointing inside opal. To recover from MC in this scenario, get a recovery instruction address and return to it from MC. OPAL will export the machine check recoverable ranges through device tree node mcheck-recoverable-ranges under ibm,opal: # hexdump /proc/device-tree/ibm,opal/mcheck-recoverable-ranges 0000000 0000 0000 3000 2804 0000 000c 0000 0000 0000010 3000 2814 0000 0000 3000 27f0 0000 000c 0000020 0000 0000 3000 2814 xxxx xxxx xxxx xxxx 0000030 llll llll yyyy yyyy yyyy yyyy ... ... # where: xxxx xxxx xxxx xxxx = Starting instruction address llll llll = Length of the address range. yyyy yyyy yyyy yyyy = recovery address Each recoverable address range entry is (start address, len, recovery address), 2 cells each for start and recovery address, 1 cell for len, totalling 5 cells per entry. During kernel boot time, build up the recovery table with the list of recovery ranges from device-tree node which will be used during machine check exception to recover from MMIO SCOM UE. Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-12-30powerpc: Fix endian issues in power7/8 machine check handlerAnton Blanchard
The SLB save area is shared with the hypervisor and is defined as big endian, so we need to byte swap on little endian builds. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-12-05powerpc/book3s: Decode and save machine check event.Mahesh Salgaonkar
Now that we handle machine check in linux, the MCE decoding should also take place in linux host. This info is crucial to log before we go down in case we can not handle the machine check errors. This patch decodes and populates a machine check event which contain high level meaning full MCE information. We do this in real mode C code with ME bit on. The MCE information is still available on emergency stack (in pt_regs structure format). Even if we take another exception at this point the MCE early handler will allocate a new stack frame on top of current one. So when we return back here we still have our MCE information safe on current stack. We use per cpu buffer to save high level MCE information. Each per cpu buffer is an array of machine check event structure indexed by per cpu counter mce_nest_count. The mce_nest_count is incremented every time we enter machine check early handler in real mode to get the current free slot (index = mce_nest_count - 1). The mce_nest_count is decremented once the MCE info is consumed by virtual mode machine exception handler. This patch provides save_mce_event(), get_mce_event() and release_mce_event() generic routines that can be used by machine check handlers to populate and retrieve the event. The routine release_mce_event() will free the event slot so that it can be reused. Caller can invoke get_mce_event() with a release flag either to release the event slot immediately OR keep it so that it can be fetched again. The event slot can be also released anytime by invoking release_mce_event(). This patch also updates kvm code to invoke get_mce_event to retrieve generic mce event rather than paca->opal_mce_evt. The KVM code always calls get_mce_event() with release flags set to false so that event is available for linus host machine If machine check occurs while we are in guest, KVM tries to handle the error. If KVM is able to handle MC error successfully, it enters the guest and delivers the machine check to guest. If KVM is not able to handle MC error, it exists the guest and passes the control to linux host machine check handler which then logs MC event and decides how to handle it in linux host. In failure case, KVM needs to make sure that the MC event is available for linux host to consume. Hence KVM always calls get_mce_event() with release flags set to false and later it invokes release_mce_event() only if it succeeds to handle error. Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-12-05powerpc/book3s: Flush SLB/TLBs if we get SLB/TLB machine check errors on power8.Mahesh Salgaonkar
This patch handles the memory errors on power8. If we get a machine check exception due to SLB or TLB errors, then flush SLBs/TLBs and reload SLBs to recover. Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Acked-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-12-05powerpc/book3s: Flush SLB/TLBs if we get SLB/TLB machine check errors on power7.Mahesh Salgaonkar
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: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>