linux.git/arch/powerpc/kernel/mce.c, branch v5.12

powerpc: move NMI entry/exit code into wrapper

2021-02-08T13:10:50+00:00

This moves the common NMI entry and exit code into the interrupt handler
wrappers.

This changes the behaviour of soft-NMI (watchdog) and HMI interrupts, and
also MCE interrupts on 64e, by adding missing parts of the NMI entry to
them.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210130130852.2952424-40-npiggin@gmail.com

powerpc: convert interrupt handlers to use wrappers

2021-02-08T13:02:12+00:00

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210130130852.2952424-29-npiggin@gmail.com

powerpc/mce: Remove per cpu variables from MCE handlers

2021-01-31T11:35:49+00:00

Access to per-cpu variables requires translation to be enabled on
pseries machine running in hash mmu mode, Since part of MCE handler
runs in realmode and part of MCE handling code is shared between ppc
architectures pseries and powernv, it becomes difficult to manage
these variables differently on different architectures, So have
these variables in paca instead of having them as per-cpu variables
to avoid complications.

Signed-off-by: Ganesh Goudar 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210128104143.70668-2-ganeshgr@linux.ibm.com

powerpc/mce: Include prototypes

2021-01-30T00:39:29+00:00

It fixes these W=1 compile errors :

../arch/powerpc/kernel/mce.c:591:14: error: no previous prototype for ‘machine_check_early’ [-Werror=missing-prototypes]
  591 | long notrace machine_check_early(struct pt_regs *regs)
      |              ^~~~~~~~~~~~~~~~~~~
../arch/powerpc/kernel/mce.c:725:6: error: no previous prototype for ‘hmi_exception_realmode’ [-Werror=missing-prototypes]
  725 | long hmi_exception_realmode(struct pt_regs *regs)
      |      ^~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Cédric Le Goater 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210104143206.695198-8-clg@kaod.org

powerpc/64s: Remove "Host" from MCE logging

2020-12-03T14:01:23+00:00

"Host" caused machine check is printed when the kernel sees a MCE
hit in this kernel or userspace, and "Guest" if it hit one of its
guests. This is confusing when a guest kernel handles a hypervisor-
delivered MCE, it also prints "Host".

Just remove "Host". "Guest" is adequate to make the distinction.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20201128070728.825934-8-npiggin@gmail.com

powerpc/64s/powernv: Allow KVM to handle guest machine check details

2020-12-03T14:01:22+00:00

KVM has strategies to perform machine check recovery. If a MCE hits
in a guest, have the low level handler just decode and save the MCE
but not try to recover anything, so KVM can deal with it.

The host does not own SLBs and does not need to report the SLB state
in case of a multi-hit for example, or know about the virtual memory
map of the guest.

UE and memory poisoning of guest pages in the host is one thing that
is possibly not completely robust at the moment, but this too needs
to go via KVM (possibly via the guest and back out to host via hcall)
rather than being handled at a low level in the host handler.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20201128070728.825934-3-npiggin@gmail.com

powerpc/mce: Avoid nmi_enter/exit in real mode on pseries hash

2020-10-16T09:13:55+00:00

Use of nmi_enter/exit in real mode handler causes the kernel to panic
and reboot on injecting SLB mutihit on pseries machine running in hash
MMU mode, because these calls try to accesses memory outside RMO
region in real mode handler where translation is disabled.

Add check to not to use these calls on pseries machine running in hash
MMU mode.

Fixes: 116ac378bb3f ("powerpc/64s: machine check interrupt update NMI accounting")
Cc: stable@vger.kernel.org # v5.8+
Signed-off-by: Ganesh Goudar 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20201009064005.19777-2-ganeshgr@linux.ibm.com

powerpc/64s: Move HMI IRQ stat from percpu variable to paca.

2020-07-29T13:47:53+00:00

With the proposed change in percpu bootmem allocator to use page
mapping [1], the percpu first chunk memory area can come from vmalloc
ranges. This makes the HMI (Hypervisor Maintenance Interrupt) handler
crash the kernel whenever percpu variable is accessed in real mode.
This patch fixes this issue by moving the HMI IRQ stat inside paca for
safe access in realmode.

[1] https://lore.kernel.org/linuxppc-dev/20200608070904.387440-1-aneesh.kumar@linux.ibm.com/

Suggested-by: Aneesh Kumar K.V 
Signed-off-by: Mahesh Salgaonkar 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/159290806973.3642154.5244613424529764050.stgit@jupiter

powerpc/powernv: Machine check handler for POWER10

2020-07-23T07:43:30+00:00

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20200702233343.1128026-1-npiggin@gmail.com

powerpc/mce: Add MCE notification chain

2020-07-20T12:57:56+00:00

Introduce notification chain which lets us know about uncorrected memory
errors(UE). This would help prospective users in pmem or nvdimm subsystem
to track bad blocks for better handling of persistent memory allocations.

Signed-off-by: Santosh Sivaraj 
Signed-off-by: Ganesh Goudar 
Reviewed-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20200709135142.721504-1-santosh@fossix.org