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The 'bd' command will now print an error and not set the breakpoint on
P9.
Signed-off-by: Michael Neuling <[email protected]>
[mpe: Unsplit quoted string]
Signed-off-by: Michael Ellerman <[email protected]>
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This updates the ptrace code to use ppc_breakpoint_available().
We now advertise via PPC_PTRACE_GETHWDBGINFO zero breakpoints when the
DAWR is missing (ie. POWER9). This results in GDB falling back to
software emulation of the breakpoint (which is slow).
For the features advertised by PPC_PTRACE_GETHWDBGINFO, we keep
advertising DAWR as if we don't GDB assumes 1 breakpoint irrespective
of the number of breakpoints advertised. GDB then fails later when
trying to set this one breakpoint.
Signed-off-by: Michael Neuling <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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Add ppc_breakpoint_available() to determine if a breakpoint is
available currently via the DAWR or DABR.
Signed-off-by: Michael Neuling <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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Checking for a "fully active" device state requires testing two flag
bits, which is open coded in several places, so add a function to do
it.
Signed-off-by: Sam Bobroff <[email protected]>
Reviewed-by: Alexey Kardashevskiy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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The caller will always pass NULL for 'rmv_data' when
'eeh_aware_driver' is true, so the first two calls to
eeh_pe_dev_traverse() can be combined without changing behaviour as
can the two arms of the final 'if' block.
This should not change behaviour.
Signed-off-by: Sam Bobroff <[email protected]>
Reviewed-by: Alexey Kardashevskiy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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eeh_reset_device() tests the value of 'bus' more than once but the
only caller, eeh_handle_normal_device() does this test itself and will
never pass NULL.
So, remove the dead tests.
This should not change behaviour.
Signed-off-by: Sam Bobroff <[email protected]>
Reviewed-by: Alexey Kardashevskiy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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It is currently difficult to understand the behaviour of
eeh_reset_device() due to the way it's parameters are used. In
particular, when 'bus' is NULL, it's value is still necessary so the
same value is looked up again locally under a different name
('frozen_bus') but behaviour is changed.
To clarify this, add a new parameter 'driver_eeh_aware', and have the
caller set it when it would have passed NULL for 'bus' and always pass
a value for 'bus'. Then change any test that was on 'bus' to one on
'!driver_eeh_aware' and replace uses of 'frozen_bus' with 'bus'.
Also update the function's comment.
This should not change behaviour.
Signed-off-by: Sam Bobroff <[email protected]>
Reviewed-by: Alexey Kardashevskiy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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The name "frozen_bus" is misleading: it's not necessarily frozen, it's
just the PE's PCI bus.
Signed-off-by: Sam Bobroff <[email protected]>
Reviewed-by: Alexey Kardashevskiy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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Remove a test that checks if "frozen_bus" is NULL, because it cannot
have changed since it was tested at the start of the function and so
must be true here.
Signed-off-by: Sam Bobroff <[email protected]>
Reviewed-by: Alexey Kardashevskiy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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Commit "0ba178888b05 powerpc/eeh: Remove reference to PCI device"
removed a call to pci_dev_get() from __eeh_addr_cache_get_device() but
did not update the comment to match.
Signed-off-by: Sam Bobroff <[email protected]>
Reviewed-by: Alexey Kardashevskiy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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Currently the EEH_PE_RECOVERING flag for a PE is managed by both the
caller and callee of eeh_handle_normal_event() (among other places not
considered here). This is complicated by the fact that the PE may
or may not have been invalidated by the call.
So move the callee's handling into eeh_handle_normal_event(), which
clarifies it and allows the return type to be changed to void (because
it no longer needs to indicate at the PE has been invalidated).
This should not change behaviour except in eeh_event_handler() where
it was previously possible to cause eeh_pe_state_clear() to be called
on an invalid PE, which is now avoided.
Signed-off-by: Sam Bobroff <[email protected]>
Reviewed-by: Alexey Kardashevskiy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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The function eeh_handle_event(pe) does nothing other than switching
between calling eeh_handle_normal_event(pe) and
eeh_handle_special_event(). However it is only called in two places,
one where pe can't be NULL and the other where it must be NULL (see
eeh_event_handler()) so it does nothing but obscure the flow of
control.
So, remove it.
Signed-off-by: Sam Bobroff <[email protected]>
Reviewed-by: Alexey Kardashevskiy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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enabled
GPUs and the corresponding NVLink bridges get different PEs as they
have separate translation validation entries (TVEs). We put these PEs
to the same IOMMU group so they cannot be passed through separately.
So the iommu_table_group_ops::set_window/unset_window for GPUs do set
tables to the NPU PEs as well which means that iommu_table's list of
attached PEs (iommu_table_group_link) has both GPU and NPU PEs linked.
This list is used for TCE cache invalidation.
The problem is that NPU PE has just a single TVE and can be programmed
to point to 32bit or 64bit windows while GPU PE has two (as any other
PCI device). So we end up having an 32bit iommu_table struct linked to
both PEs even though only the 64bit TCE table cache can be invalidated
on NPU. And a relatively recent skiboot detects this and prints
errors.
This changes GPU's iommu_table_group_ops::set_window/unset_window to
make sure that NPU PE is only linked to the table actually used by the
hardware. If there are two tables used by an IOMMU group, the NPU PE
will use the last programmed one which with the current use scenarios
is expected to be a 64bit one.
Signed-off-by: Alexey Kardashevskiy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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Fixes: 912cc87a6 "powerpc/mm/radix: Add LPID based tlb flush helpers"
Signed-off-by: Alexey Kardashevskiy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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With enabled DEBUG, there is a compile error:
"error: ‘flags’ is used uninitialized in this function".
This moves pr_devel() little further where @flags are initialized.
Signed-off-by: Alexey Kardashevskiy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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Currently the pseries kernel advertises radix MMU support even if
the actual support is disabled via the CONFIG_PPC_RADIX_MMU option.
This adds a check for CONFIG_PPC_RADIX_MMU to avoid advertising radix
to the hypervisor.
Suggested-by: Paul Mackerras <[email protected]>
Signed-off-by: Alexey Kardashevskiy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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Fix the warning messages for stop_machine_change_mapping(), and a number
of other affected functions in its call chain.
All modified functions are under CONFIG_MEMORY_HOTPLUG, so __meminit
is okay (keeps them / does not discard them).
Boot-tested on powernv/power9/radix-mmu and pseries/power8/hash-mmu.
$ make -j$(nproc) CONFIG_DEBUG_SECTION_MISMATCH=y vmlinux
...
MODPOST vmlinux.o
WARNING: vmlinux.o(.text+0x6b130): Section mismatch in reference from the function stop_machine_change_mapping() to the function .meminit.text:create_physical_mapping()
The function stop_machine_change_mapping() references
the function __meminit create_physical_mapping().
This is often because stop_machine_change_mapping lacks a __meminit
annotation or the annotation of create_physical_mapping is wrong.
WARNING: vmlinux.o(.text+0x6b13c): Section mismatch in reference from the function stop_machine_change_mapping() to the function .meminit.text:create_physical_mapping()
The function stop_machine_change_mapping() references
the function __meminit create_physical_mapping().
This is often because stop_machine_change_mapping lacks a __meminit
annotation or the annotation of create_physical_mapping is wrong.
...
Signed-off-by: Mauricio Faria de Oliveira <[email protected]>
Acked-by: Balbir Singh <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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Add a definition for cpu_show_spectre_v2() to override the generic
version. This has several permuations, though in practice some may not
occur we cater for any combination.
The most verbose is:
Mitigation: Indirect branch serialisation (kernel only), Indirect
branch cache disabled, ori31 speculation barrier enabled
We don't treat the ori31 speculation barrier as a mitigation on its
own, because it has to be *used* by code in order to be a mitigation
and we don't know if userspace is doing that. So if that's all we see
we say:
Vulnerable, ori31 speculation barrier enabled
Signed-off-by: Michael Ellerman <[email protected]>
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Add a definition for cpu_show_spectre_v1() to override the generic
version. Currently this just prints "Not affected" or "Vulnerable"
based on the firmware flag.
Although the kernel does have array_index_nospec() in a few places, we
haven't yet audited all the powerpc code to see where it's necessary,
so for now we don't list that as a mitigation.
Signed-off-by: Michael Ellerman <[email protected]>
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Now that we have the security flags we can simplify the code in
pseries_setup_rfi_flush() because the security flags have pessimistic
defaults.
Signed-off-by: Michael Ellerman <[email protected]>
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Now that we have the security flags we can significantly simplify the
code in pnv_setup_rfi_flush(), because we can use the flags instead of
checking device tree properties and because the security flags have
pessimistic defaults.
Signed-off-by: Michael Ellerman <[email protected]>
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Now that we have the security feature flags we can make the
information displayed in the "meltdown" file more informative.
Signed-off-by: Michael Ellerman <[email protected]>
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This landed in setup_64.c for no good reason other than we had nowhere
else to put it. Now that we have a security-related file, that is a
better place for it so move it.
Signed-off-by: Michael Ellerman <[email protected]>
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Now that we have feature flags for security related things, set or
clear them based on what we see in the device tree provided by
firmware.
Signed-off-by: Michael Ellerman <[email protected]>
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Now that we have feature flags for security related things, set or
clear them based on what we receive from the hypercall.
Signed-off-by: Michael Ellerman <[email protected]>
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This commit adds security feature flags to reflect the settings we
receive from firmware regarding Spectre/Meltdown mitigations.
The feature names reflect the names we are given by firmware on bare
metal machines. See the hostboot source for details.
Arguably these could be firmware features, but that then requires them
to be read early in boot so they're available prior to asm feature
patching, but we don't actually want to use them for patching. We may
also want to dynamically update them in future, which would be
incompatible with the way firmware features work (at the moment at
least). So for now just make them separate flags.
Signed-off-by: Michael Ellerman <[email protected]>
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Add some additional values which have been defined for the
H_GET_CPU_CHARACTERISTICS hypercall.
Signed-off-by: Michael Ellerman <[email protected]>
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We might have migrated to a machine that uses a different flush type,
or doesn't need flushing at all.
Signed-off-by: Michael Ellerman <[email protected]>
Signed-off-by: Mauricio Faria de Oliveira <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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Currently the rfi-flush messages print 'Using <type> flush' for all
enabled_flush_types, but that is not necessarily true -- as now the
fallback flush is always enabled on pseries, but the fixup function
overwrites its nop/branch slot with other flush types, if available.
So, replace the 'Using <type> flush' messages with '<type> flush is
available'.
Also, print the patched flush types in the fixup function, so users
can know what is (not) being used (e.g., the slower, fallback flush,
or no flush type at all if flush is disabled via the debugfs switch).
Suggested-by: Michael Ellerman <[email protected]>
Signed-off-by: Mauricio Faria de Oliveira <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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This ensures the fallback flush area is always allocated on pseries,
so in case a LPAR is migrated from a patched to an unpatched system,
it is possible to enable the fallback flush in the target system.
Signed-off-by: Michael Ellerman <[email protected]>
Signed-off-by: Mauricio Faria de Oliveira <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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For PowerVM migration we want to be able to call setup_rfi_flush()
again after we've migrated the partition.
To support that we need to check that we're not trying to allocate the
fallback flush area after memblock has gone away (i.e., boot-time only).
Signed-off-by: Michael Ellerman <[email protected]>
Signed-off-by: Mauricio Faria de Oliveira <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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rfi_flush_enable() includes a check to see if we're already
enabled (or disabled), and in that case does nothing.
But that means calling setup_rfi_flush() a 2nd time doesn't actually
work, which is a bit confusing.
Move that check into the debugfs code, where it really belongs.
Signed-off-by: Michael Ellerman <[email protected]>
Signed-off-by: Mauricio Faria de Oliveira <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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These events either do not count, or do not count correctly, so to
prevent user confusion block counting them at all.
Signed-off-by: Madhavan Srinivasan <[email protected]>
[mpe: Change log]
Signed-off-by: Michael Ellerman <[email protected]>
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These events either do not count, or do not count correctly, so to
prevent user confusion block counting them at all.
Signed-off-by: Madhavan Srinivasan <[email protected]>
[mpe: Change log]
Signed-off-by: Michael Ellerman <[email protected]>
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Introduce code to support addition of blacklisted events for a
processor version. Blacklisted events are events that are known to not
count correctly on that CPU revision, and so should be prevented from
being counted so as to avoid user confusion.
A 'pointer' and 'int' variable to hold the number of events are added
to 'struct power_pmu', along with a generic function to loop through
the list to validate the given event. Generic function
'is_event_blacklisted' is called in power_pmu_event_init() to detect
and reject early.
Signed-off-by: Madhavan Srinivasan <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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Sampled Data Address Register (SDAR) is a 64-bit register that
contains the effective address of the storage operand of an
instruction that was being executed, possibly out-of-order, at or
around the time that the Performance Monitor alert occurred.
In certain scenario SDAR happen to contain the kernel address even for
userspace only sampling. Add checks to prevent it.
Signed-off-by: Madhavan Srinivasan <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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The current Branch History Rolling Buffer (BHRB) code does not check
for any privilege levels before updating the data from BHRB. This
could leak kernel addresses to userspace even when profiling only with
userspace privileges. Add proper checks to prevent it.
Acked-by: Balbir Singh <[email protected]>
Signed-off-by: Madhavan Srinivasan <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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Current code in power_pmu_disable() does not clear the sampling
registers like Sampling Instruction Address Register (SIAR) and
Sampling Data Address Register (SDAR) after disabling the PMU. Since
these are userspace readable and could contain kernel addresses, add
code to explicitly clear the content of these registers.
Also add a "context synchronizing instruction" to enforce no further
updates to these registers as suggested by Power ISA v3.0B. From
section 9.4, on page 1108:
"If an mtspr instruction is executed that changes the value of a
Performance Monitor register other than SIAR, SDAR, and SIER, the
change is not guaranteed to have taken effect until after a
subsequent context synchronizing instruction has been executed (see
Chapter 11. "Synchronization Requirements for Context Alterations"
on page 1133)."
Signed-off-by: Madhavan Srinivasan <[email protected]>
[mpe: Massage change log and add ISA reference]
Signed-off-by: Michael Ellerman <[email protected]>
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On POWER9, since commit cc3d2940133d ("powerpc/64: Enable use of radix
MMU under hypervisor on POWER9", 2017-01-30), we set both the radix and
HPT bits in the client-architecture-support (CAS) vector, which tells
the hypervisor that we can do either radix or HPT. According to PAPR,
if we use this combination we are promising to do a H_REGISTER_PROC_TBL
hcall later on to let the hypervisor know whether we are doing radix
or HPT. We currently do this call if we are doing radix but not if
we are doing HPT. If the hypervisor is able to support both radix
and HPT guests, it would be entitled to defer allocation of the HPT
until the H_REGISTER_PROC_TBL call, and to fail any attempts to create
HPTEs until the H_REGISTER_PROC_TBL call. Thus we need to do a
H_REGISTER_PROC_TBL call when we are doing HPT; otherwise we may
crash at boot time.
This adds the code to call H_REGISTER_PROC_TBL in this case, before
we attempt to create any HPT entries using H_ENTER.
Fixes: cc3d2940133d ("powerpc/64: Enable use of radix MMU under hypervisor on POWER9")
Cc: [email protected] # v4.11+
Signed-off-by: Paul Mackerras <[email protected]>
Reviewed-by: Suraj Jitindar Singh <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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The SLB bad address handler's trap number fixup does not preserve the
low bit that indicates nonvolatile GPRs have not been saved. This
leads save_nvgprs to skip saving them, and subsequent functions and
return from interrupt will think they are saved.
This causes kernel branch-to-garbage debugging to not have correct
registers, can also cause userspace to have its registers clobbered
after a segfault.
Fixes: f0f558b131db ("powerpc/mm: Preserve CFAR value on SLB miss caused by access to bogus address")
Cc: [email protected] # v4.9+
Signed-off-by: Nicholas Piggin <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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This brings in two series from Paul, one of which touches KVM code and
may need to be merged into the kvm-ppc tree to resolve conflicts.
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This works around a hardware bug in "Nimbus" POWER9 DD2.2 processors,
where the contents of the TEXASR can get corrupted while a thread is
in fake suspend state. The workaround is for the instruction emulation
code to use the value saved at the most recent guest exit in real
suspend mode. We achieve this by simply not saving the TEXASR into
the vcpu struct on an exit in fake suspend state. We also have to
take care to set the orig_texasr field only on guest exit in real
suspend state.
This also means that on guest entry in fake suspend state, TEXASR
will be restored to the value it had on the last exit in real suspend
state, effectively counteracting any hardware-caused corruption. This
works because TEXASR may not be written in suspend state.
With this, the guest might see the wrong values in TEXASR if it reads
it while in suspend state, but will see the correct value in
non-transactional state (e.g. after a treclaim), and treclaim will
work correctly.
With this workaround, the code will actually run slightly faster, and
will operate correctly on systems without the TEXASR bug (since TEXASR
may not be written in suspend state, and is only changed by failure
recording, which will have already been done before we get into fake
suspend state). Therefore these changes are not made subject to a CPU
feature bit.
Signed-off-by: Paul Mackerras <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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This works around a hardware bug in "Nimbus" POWER9 DD2.2 processors,
where a treclaim performed in fake suspend mode can cause subsequent
reads from the XER register to return inconsistent values for the SO
(summary overflow) bit. The inconsistent SO bit state can potentially
be observed on any thread in the core. We have to do the treclaim
because that is the only way to get the thread out of suspend state
(fake or real) and into non-transactional state.
The workaround for the bug is to force the core into SMT4 mode before
doing the treclaim. This patch adds the code to do that, conditional
on the CPU_FTR_P9_TM_XER_SO_BUG feature bit.
Signed-off-by: Suraj Jitindar Singh <[email protected]>
Signed-off-by: Paul Mackerras <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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POWER9 has hardware bugs relating to transactional memory and thread
reconfiguration (changes to hardware SMT mode). Specifically, the core
does not have enough storage to store a complete checkpoint of all the
architected state for all four threads. The DD2.2 version of POWER9
includes hardware modifications designed to allow hypervisor software
to implement workarounds for these problems. This patch implements
those workarounds in KVM code so that KVM guests see a full, working
transactional memory implementation.
The problems center around the use of TM suspended state, where the
CPU has a checkpointed state but execution is not transactional. The
workaround is to implement a "fake suspend" state, which looks to the
guest like suspended state but the CPU does not store a checkpoint.
In this state, any instruction that would cause a transition to
transactional state (rfid, rfebb, mtmsrd, tresume) or would use the
checkpointed state (treclaim) causes a "soft patch" interrupt (vector
0x1500) to the hypervisor so that it can be emulated. The trechkpt
instruction also causes a soft patch interrupt.
On POWER9 DD2.2, we avoid returning to the guest in any state which
would require a checkpoint to be present. The trechkpt in the guest
entry path which would normally create that checkpoint is replaced by
either a transition to fake suspend state, if the guest is in suspend
state, or a rollback to the pre-transactional state if the guest is in
transactional state. Fake suspend state is indicated by a flag in the
PACA plus a new bit in the PSSCR. The new PSSCR bit is write-only and
reads back as 0.
On exit from the guest, if the guest is in fake suspend state, we still
do the treclaim instruction as we would in real suspend state, in order
to get into non-transactional state, but we do not save the resulting
register state since there was no checkpoint.
Emulation of the instructions that cause a softpatch interrupt is
handled in two paths. If the guest is in real suspend mode, we call
kvmhv_p9_tm_emulation_early() to handle the cases where the guest is
transitioning to transactional state. This is called before we do the
treclaim in the guest exit path; because we haven't done treclaim, we
can get back to the guest with the transaction still active. If the
instruction is a case that kvmhv_p9_tm_emulation_early() doesn't
handle, or if the guest is in fake suspend state, then we proceed to
do the complete guest exit path and subsequently call
kvmhv_p9_tm_emulation() in host context with the MMU on. This handles
all the cases including the cases that generate program interrupts
(illegal instruction or TM Bad Thing) and facility unavailable
interrupts.
The emulation is reasonably straightforward and is mostly concerned
with checking for exception conditions and updating the state of
registers such as MSR and CR0. The treclaim emulation takes care to
ensure that the TEXASR register gets updated as if it were the guest
treclaim instruction that had done failure recording, not the treclaim
done in hypervisor state in the guest exit path.
With this, the KVM_CAP_PPC_HTM capability returns true (1) even if
transactional memory is not available to host userspace.
Signed-off-by: Paul Mackerras <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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POWER9 processors up to and including "Nimbus" v2.2 have hardware
bugs relating to transactional memory and thread reconfiguration.
One of these bugs has a workaround which is to get the core into
SMT4 state temporarily. This workaround is only needed when
running bare-metal.
This patch provides a function which gets the core into SMT4 mode
by preventing threads from going to a stop state, and waking up
those which are already in a stop state. Once at least 3 threads
are not in a stop state, the core will be in SMT4 and we can
continue.
To do this, we add a "dont_stop" flag to the paca to tell the
thread not to go into a stop state. If this flag is set,
power9_idle_stop() just returns immediately with a return value
of 0. The pnv_power9_force_smt4_catch() function does the following:
1. Set the dont_stop flag for each thread in the core, except
ourselves (in fact we use an atomic_inc() in case more than
one thread is calling this function concurrently).
2. See how many threads are awake, indicated by their
requested_psscr field in the paca being 0. If this is at
least 3, skip to step 5.
3. Send a doorbell interrupt to each thread that was seen as
being in a stop state in step 2.
4. Until at least 3 threads are awake, scan the threads to which
we sent a doorbell interrupt and check if they are awake now.
This relies on the following properties:
- Once dont_stop is non-zero, requested_psccr can't go from zero to
non-zero, except transiently (and without the thread doing stop).
- requested_psscr being zero guarantees that the thread isn't in
a state-losing stop state where thread reconfiguration could occur.
- Doing stop with a PSSCR value of 0 won't be a state-losing stop
and thus won't allow thread reconfiguration.
- Once threads_per_core/2 + 1 (i.e. 3) threads are awake, the core
must be in SMT4 mode, since SMT modes are powers of 2.
This does add a sync to power9_idle_stop(), which is necessary to
provide the correct ordering between setting requested_psscr and
checking dont_stop. The overhead of the sync should be unnoticeable
compared to the latency of going into and out of a stop state.
Because some objected to incurring this extra latency on systems where
the XER[SO] bug is not relevant, I have put the test in
power9_idle_stop inside a feature section. This means that
pnv_power9_force_smt4_catch() WILL NOT WORK correctly on systems
without the CPU_FTR_P9_TM_XER_SO_BUG feature bit set, and will
probably hang the system.
In order to cater for uses where the caller has an operation that
has to be done while the core is in SMT4, the core continues to be
kept in SMT4 after pnv_power9_force_smt4_catch() function returns,
until the pnv_power9_force_smt4_release() function is called.
It undoes the effect of step 1 above and allows the other threads
to go into a stop state.
Signed-off-by: Paul Mackerras <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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This adds a CPU feature bit which is set for POWER9 "Nimbus" DD2.2
processors which will be used to enable the hypervisor to assist
hardware with the handling of checkpointed register values while the
CPU is in suspend state, in order to work around hardware bugs. The
hardware assistance for these workarounds introduced a new hardware
bug relating to the XER[SO] bit. We add a separate feature bit for
this bug in case future chips fix it while still requiring the
hypervisor assistance with suspend state.
When the dt_cpu_ftrs subsystem is in use, the software assistance can
be enabled using a "tm-suspend-hypervisor-assist" node in the device
tree, and a "tm-suspend-xer-so-bug" node enables the workarounds for
the XER[SO] bug. In the absence of such nodes, a quirk enables both
for POWER9 "Nimbus" DD2.2 processors.
Signed-off-by: Paul Mackerras <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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This moves all the CPU feature bits that are only used on 32-bit
machines to the top 20 bits of the CPU feature word and arranges
for them to be defined only in 32-bit builds. The features that
are common to 32-bit and 64-bit machines are moved to bits 0-11
of the CPU feature word. This means that for 64-bit platforms,
bits 44-63 can now be used for new features that only exist on
64-bit machines. (These bit numbers are counting from the right,
i.e. the LSB is bit 0.)
Because CPU_FTR_L3_DISABLE_NAP moved from the low 16 bits to the high
16 bits, we have to adjust some assembly code. Also, CPU_FTR_EMB_HV
moved from the high 16 bits to the low 16 bits.
Note that CPU_FTR_REAL_LE only applies to 64-bit chips, because only
64-bit chips (POWER6, 7, 8, 9) have a true little-endian mode that is
a CPU execution mode as opposed to being a page attribute.
With this we now have 20 free CPU feature bits on 64-bit machines.
Signed-off-by: Paul Mackerras <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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The CPU_FTR_L2CSR bit is never tested anywhere, so let's reclaim the
bit.
The last usage was removed in 86d63363defc ("powerpc/e500mc: Remove
dead L2 flushing code in idle_e500.S") (Jun 2015).
Signed-off-by: Paul Mackerras <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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All PowerPC CPUs other than the original PPC601 have a timebase
register rather than the "real-time clock" (RTC) register that the
PPC601 (and the original POWER and POWER2 CPUs) had. Currently
we have a CPU feature bit to indicate the presence of the timebase,
but it makes more sense to use a bit to indicate the unusual
situation rather than the common situation. This therefore defines
a CPU_FTR_USE_RTC bit in place of the CPU_FTR_USE_TB bit, and
arranges for it to be set on PPC601 systems.
Signed-off-by: Paul Mackerras <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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On POWER9, under some circumstances, a broadcast TLB invalidation
might complete before all previous stores have drained, potentially
allowing stale stores from becoming visible after the invalidation.
This works around it by doubling up those TLB invalidations which was
verified by HW to be sufficient to close the risk window.
This will be documented in a yet-to-be-published errata.
Fixes: 1a472c9dba6b ("powerpc/mm/radix: Add tlbflush routines")
Signed-off-by: Aneesh Kumar K.V <[email protected]>
[mpe: Enable the feature in the DT CPU features code for all Power9,
rename the feature to CPU_FTR_P9_TLBIE_BUG per benh.]
Signed-off-by: Michael Ellerman <[email protected]>
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