As per PAPR we have to look for both EPOW sensor value and event
modifier to identify the type of event and take appropriate action.

In LoPAPR v1.1 section 10.2.2 includes table 136 "EPOW Action Codes":

SYSTEM_SHUTDOWN 3

The system must be shut down. An EPOW-aware OS logs the EPOW error
log information, then schedules the system to be shut down to begin
after an OS defined delay internal (default is 10 minutes.)

Then in section 10.3.2.2.8 there is table 146 "Platform Event Log
Format, Version 6, EPOW Section", which includes the "EPOW Event
Modifier":

For EPOW sensor value = 3
0x01 = Normal system shutdown with no additional delay
0x02 = Loss of utility power, system is running on UPS/Battery
0x03 = Loss of system critical functions, system should be shutdown
0x04 = Ambient temperature too high
All other values = reserved

We have a user space tool (rtas_errd) on LPAR to monitor for
EPOW_SHUTDOWN_ON_UPS. Once it gets an event it initiates shutdown
after predefined time. It also starts monitoring for any new EPOW
events. If it receives "Power restored" event before predefined time
it will cancel the shutdown. Otherwise after predefined time it will
shutdown the system.

Commit 79872e35469b ("powerpc/pseries: All events of
EPOW_SYSTEM_SHUTDOWN must initiate shutdown") changed our handling of
the "on UPS/Battery" case, to immediately shutdown the system. This
breaks existing setups that rely on the userspace tool to delay
shutdown and let the system run on the UPS.

Fixes: 79872e35469b ("powerpc/pseries: All events of EPOW_SYSTEM_SHUTDOWN must initiate shutdown")
Cc: stable@vger.kernel.org # v4.0+
Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
[mpe: Massage change log and add PAPR references]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200820061844.306460-1-hegdevasant@linux.vnet.ibm.com

Performance monitor interrupt handler checks if any counter has
overflown and calls record_and_restart() in core-book3s which invokes
perf_event_overflow() to record the sample information. Apart from
creating sample, perf_event_overflow() also does the interrupt and
period checks via perf_event_account_interrupt().

Currently we record information only if the SIAR (Sampled Instruction
Address Register) valid bit is set (using siar_valid() check) and
hence the interrupt check.

But it is possible that we do sampling for some events that are not
generating valid SIAR, and hence there is no chance to disable the
event if interrupts are more than max_samples_per_tick. This leads to
soft lockup.

Fix this by adding perf_event_account_interrupt() in the invalid SIAR
code path for a sampling event. ie if SIAR is invalid, just do
interrupt check and don't record the sample information.

Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1596717992-7321-1-git-send-email-atrajeev@linux.vnet.ibm.com

Fix a typo introduced during recent code cleanup, which could lead to
silently not freeing resources or an oops message (on PCI hotplug or
CAPI reset).

Only impacts ioda2, the code path for ioda1 is correct.

Fixes: 01e12629af4e ("powerpc/powernv/pci: Add explicit tracking of the DMA setup state")
Signed-off-by: Frederic Barrat <fbarrat@linux.ibm.com>
Reviewed-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200819130741.16769-1-fbarrat@linux.ibm.com

For a power9 KVM guest with XIVE enabled, running a test loop
where we hotplug 384 vcpus and then unplug them, the following traces
can be seen (generally within a few loops) either from the unplugged
vcpu:

cpu 65 (hwid 65) Ready to die...
Querying DEAD? cpu 66 (66) shows 2
list_del corruption. next->prev should be c00a000002470208, but was c00a000002470048
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:56!
Oops: Exception in kernel mode, sig: 5 [#1]
LE SMP NR_CPUS=2048 NUMA pSeries
Modules linked in: fuse nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 ...
CPU: 66 PID: 0 Comm: swapper/66 Kdump: loaded Not tainted 4.18.0-221.el8.ppc64le #1
NIP: c0000000007ab50c LR: c0000000007ab508 CTR: 00000000000003ac
REGS: c0000009e5a17840 TRAP: 0700 Not tainted (4.18.0-221.el8.ppc64le)
MSR: 800000000282b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 28000842 XER: 20040000
...
NIP __list_del_entry_valid+0xac/0x100
LR __list_del_entry_valid+0xa8/0x100
Call Trace:
__list_del_entry_valid+0xa8/0x100 (unreliable)
free_pcppages_bulk+0x1f8/0x940
free_unref_page+0xd0/0x100
xive_spapr_cleanup_queue+0x148/0x1b0
xive_teardown_cpu+0x1bc/0x240
pseries_mach_cpu_die+0x78/0x2f0
cpu_die+0x48/0x70
arch_cpu_idle_dead+0x20/0x40
do_idle+0x2f4/0x4c0
cpu_startup_entry+0x38/0x40
start_secondary+0x7bc/0x8f0
start_secondary_prolog+0x10/0x14

or on the worker thread handling the unplug:

pseries-hotplug-cpu: Attempting to remove CPU <NULL>, drc index: 1000013a
Querying DEAD? cpu 314 (314) shows 2
BUG: Bad page state in process kworker/u768:3 pfn:95de1
cpu 314 (hwid 314) Ready to die...
page:c00a000002577840 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x0
flags: 0x5ffffc00000000()
raw: 005ffffc00000000 5deadbeef0000100 5deadbeef0000200 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffff7f 0000000000000000
page dumped because: nonzero mapcount
Modules linked in: kvm xt_CHECKSUM ipt_MASQUERADE xt_conntrack ...
CPU: 0 PID: 548 Comm: kworker/u768:3 Kdump: loaded Not tainted 4.18.0-224.el8.bz1856588.ppc64le #1
Workqueue: pseries hotplug workque pseries_hp_work_fn
Call Trace:
dump_stack+0xb0/0xf4 (unreliable)
bad_page+0x12c/0x1b0
free_pcppages_bulk+0x5bc/0x940
page_alloc_cpu_dead+0x118/0x120
cpuhp_invoke_callback.constprop.5+0xb8/0x760
_cpu_down+0x188/0x340
cpu_down+0x5c/0xa0
cpu_subsys_offline+0x24/0x40
device_offline+0xf0/0x130
dlpar_offline_cpu+0x1c4/0x2a0
dlpar_cpu_remove+0xb8/0x190
dlpar_cpu_remove_by_index+0x12c/0x150
dlpar_cpu+0x94/0x800
pseries_hp_work_fn+0x128/0x1e0
process_one_work+0x304/0x5d0
worker_thread+0xcc/0x7a0
kthread+0x1ac/0x1c0
ret_from_kernel_thread+0x5c/0x80

The latter trace is due to the following sequence:

page_alloc_cpu_dead
drain_pages
drain_pages_zone
free_pcppages_bulk

where drain_pages() in this case is called under the assumption that
the unplugged cpu is no longer executing. To ensure that is the case,
and early call is made to __cpu_die()->pseries_cpu_die(), which runs a
loop that waits for the cpu to reach a halted state by polling its
status via query-cpu-stopped-state RTAS calls. It only polls for 25
iterations before giving up, however, and in the trace above this
results in the following being printed only .1 seconds after the
hotplug worker thread begins processing the unplug request:

pseries-hotplug-cpu: Attempting to remove CPU <NULL>, drc index: 1000013a
Querying DEAD? cpu 314 (314) shows 2

At that point the worker thread assumes the unplugged CPU is in some
unknown/dead state and procedes with the cleanup, causing the race
with the XIVE cleanup code executed by the unplugged CPU.

Fix this by waiting indefinitely, but also making an effort to avoid
spurious lockup messages by allowing for rescheduling after polling
the CPU status and printing a warning if we wait for longer than 120s.

Fixes: eac1e731b59ee ("powerpc/xive: guest exploitation of the XIVE interrupt controller")
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Tested-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
[mpe: Trim oopses in change log slightly for readability]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200811161544.10513-1-mdroth@linux.vnet.ibm.com

When MODULES_VADDR is defined, is_module_segment() shall check the
address against it instead of checking agains VMALLOC_START.

Fixes: 6ca055322da8 ("powerpc/32s: Use dedicated segment for modules with STRICT_KERNEL_RWX")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/07884ed033c31e074747b7eb8eaa329d15db07ec.1596641219.git.christophe.leroy@csgroup.eu

On BOOK3S_32, when we have modules and strict kernel RWX, modules
are not in vmalloc space but in a dedicated segment that is
below PAGE_OFFSET.

So KASAN_SHADOW_START must take it into account.

MODULES_VADDR can't be used because it is not defined yet
in kasan.h

Fixes: 6ca055322da8 ("powerpc/32s: Use dedicated segment for modules with STRICT_KERNEL_RWX")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/6eddca2d5611fd57312a88eae31278c87a8fc99d.1596641224.git.christophe.leroy@csgroup.eu

Commit ("03fd42d458fb powerpc/fixmap: Fix FIX_EARLY_DEBUG_BASE when
page size is 256k") reworked the setup of the early debug area and
mistakenly replaced 128 * 1024 by SZ_128.

Change to SZ_128K to restore the original 128 kbytes size of the area.

Fixes: 03fd42d458fb ("powerpc/fixmap: Fix FIX_EARLY_DEBUG_BASE when page size is 256k")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/996184974d674ff984643778cf1cdd7fe58cc065.1597644194.git.christophe.leroy@csgroup.eu

IS_ENABLED() instead of #ifdef still requires variable declaration.
In this specific case, default_uamor is declared in asm/pkeys.h which
is only included if PPC_MEM_KEYS is enabled.

arch/powerpc/mm/book3s64/hash_utils.c: In function ‘hash__early_init_mmu_secondary’:
arch/powerpc/mm/book3s64/hash_utils.c:1119:21: error: ‘default_uamor’ undeclared (first use in this function)
1119 | mtspr(SPRN_UAMOR, default_uamor);
| ^~~~~~~~~~~~~

Fixes: 6553fb799f60 ("powerpc/pkeys: Fix boot failures with Nemo board (A-EON AmigaOne X1000)")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200817103301.158836-1-aneesh.kumar@linux.ibm.com

__machine_check_early_realmode_p*() are currently declared as extern
in cputable.c and because of this when compiled with "C=1" (which
enables semantic checker) produces these warnings.

CHECK arch/powerpc/kernel/mce_power.c
arch/powerpc/kernel/mce_power.c:709:6: warning: symbol '__machine_check_early_realmode_p7' was not declared. Should it be static?
arch/powerpc/kernel/mce_power.c:717:6: warning: symbol '__machine_check_early_realmode_p8' was not declared. Should it be static?
arch/powerpc/kernel/mce_power.c:722:6: warning: symbol '__machine_check_early_realmode_p9' was not declared. Should it be static?
arch/powerpc/kernel/mce_power.c:740:6: warning: symbol '__machine_check_early_realmode_p10' was not declared. Should it be static?

Patch here moves the declaration to asm/mce.h and includes the same in
cputable.c

Fixes: ae744f3432d3 ("powerpc/book3s: Flush SLB/TLBs if we get SLB/TLB machine check errors on power8")
Fixes: 7b9f71f974a1 ("powerpc/64s: POWER9 machine check handler")
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200817005618.3305028-1-maddy@linux.ibm.com

Add a raw mode cputable entry for POWER10. Copies most of the fields
from commit a3ea40d5c736 ("powerpc: Add POWER10 architected mode")
except for oprofile_cpu_type, machine_check_early, pvr_mask and
pvr_mask fields. On bare metal systems we use DT CPU features, which
doesn't need a cputable entry. But in VMs we still rely on the raw
cputable entry to set the correct values for the PMU related fields.

Fixes: a3ea40d5c736 ("powerpc: Add POWER10 architected mode")
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
[mpe: Reorder vs cleanup patch and add Fixes tag]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200817005618.3305028-2-maddy@linux.ibm.com

Include capability flag PERF_PMU_CAP_EXTENDED_REGS for power10 and
expose MMCR3, SIER2, SIER3 registers as part of extended regs. Also
introduce PERF_REG_PMU_MASK_31 to define extended mask value at
runtime for power10.

Suggested-by: Ryan Grimm <grimm@linux.ibm.com>
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Tested-by: Nageswara R Sastry <nasastry@in.ibm.com>
Reviewed-by: Kajol Jain <kjain@linux.ibm.com>
Reviewed-and-tested-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1596794701-23530-3-git-send-email-atrajeev@linux.vnet.ibm.com

Add support for perf extended register capability in powerpc. The
capability flag PERF_PMU_CAP_EXTENDED_REGS, is used to indicate the
PMU which support extended registers. The generic code define the mask
of extended registers as 0 for non supported architectures.

Patch adds extended regs support for power9 platform by exposing
MMCR0, MMCR1 and MMCR2 registers.

REG_RESERVED mask needs update to include extended regs.
PERF_REG_EXTENDED_MASK, contains mask value of the supported
registers, is defined at runtime in the kernel based on platform since
the supported registers may differ from one processor version to
another and hence the MASK value.

With the patch:

available registers: r0 r1 r2 r3 r4 r5 r6 r7 r8 r9 r10 r11
r12 r13 r14 r15 r16 r17 r18 r19 r20 r21 r22 r23 r24 r25 r26
r27 r28 r29 r30 r31 nip msr orig_r3 ctr link xer ccr softe
trap dar dsisr sier mmcra mmcr0 mmcr1 mmcr2

PERF_RECORD_SAMPLE(IP, 0x1): 4784/4784: 0 period: 1 addr: 0
... intr regs: mask 0xffffffffffff ABI 64-bit
.... r0 0xc00000000012b77c
.... r1 0xc000003fe5e03930
.... r2 0xc000000001b0e000
.... r3 0xc000003fdcddf800
.... r4 0xc000003fc7880000
.... r5 0x9c422724be
.... r6 0xc000003fe5e03908
.... r7 0xffffff63bddc8706
.... r8 0x9e4
.... r9 0x0
.... r10 0x1
.... r11 0x0
.... r12 0xc0000000001299c0
.... r13 0xc000003ffffc4800
.... r14 0x0
.... r15 0x7fffdd8b8b00
.... r16 0x0
.... r17 0x7fffdd8be6b8
.... r18 0x7e7076607730
.... r19 0x2f
.... r20 0xc00000001fc26c68
.... r21 0xc0002041e4227e00
.... r22 0xc00000002018fb60
.... r23 0x1
.... r24 0xc000003ffec4d900
.... r25 0x80000000
.... r26 0x0
.... r27 0x1
.... r28 0x1
.... r29 0xc000000001be1260
.... r30 0x6008010
.... r31 0xc000003ffebb7218
.... nip 0xc00000000012b910
.... msr 0x9000000000009033
.... orig_r3 0xc00000000012b86c
.... ctr 0xc0000000001299c0
.... link 0xc00000000012b77c
.... xer 0x0
.... ccr 0x28002222
.... softe 0x1
.... trap 0xf00
.... dar 0x0
.... dsisr 0x80000000000
.... sier 0x0
.... mmcra 0x80000000000
.... mmcr0 0x82008090
.... mmcr1 0x1e000000
.... mmcr2 0x0
... thread: perf:4784

Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com>
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Tested-by: Nageswara R Sastry <nasastry@in.ibm.com>
Reviewed-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Reviewed-by: Kajol Jain <kjain@linux.ibm.com>
Reviewed-and-tested-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1596794701-23530-2-git-send-email-atrajeev@linux.vnet.ibm.com

On POWER10 bit 12 in the PVR indicates if the core is SMT4 or SMT8.
Bit 12 is set for SMT4.

Without this patch, /proc/cpuinfo on a SMT4 DD1 POWER10 looks like
this:
cpu : POWER10, altivec supported
revision : 17.0 (pvr 0080 1100)

Fixes: a3ea40d5c736 ("powerpc: Add POWER10 architected mode")
Cc: stable@vger.kernel.org # v5.8
Signed-off-by: Michael Neuling <mikey@neuling.org>
Reviewed-by: Vaidyanathan Srinivasan <svaidy@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200803035600.1820371-1-mikey@neuling.org