Merge in ARM PMU and perf updates for 4.15:

  - Support for the Statistical Profiling Extension
  - Support for Hisilicon's SoC PMU
Signed-off-by: Will Deacon <will.deacon@arm.com>

arm_pmu interrupts are maked as PERCPU even when these are not local
physical interrupts to a single CPU. When using non-local interrupts,
interrupts marked as PERCPU will not get freed not disabled properly
by the PMU driver.

Check if interrupts are local to a single CPU with PERCPU_DEVID since
this is what the PMU driver really needs to know.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

irq_is_percpu indicates whether an irq should only target a single cpu.
PERCPU_DEVID flag indicates that an irq can be configured differently on
each cpu it can target.

Provide a function to check whether an irq is PERCPU_DEVID.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Julien Thierry <julien.thierry@arm.com>

Now that the ARM ARM clearly specifies the rules for inferring
the values of the ID register fields, fix the types of the
feature bits we have in the kernel.

As per ARM ARM DDI0487B.b, section D10.1.4 "Principles of the
ID scheme for fields in ID registers" lists the registers to
which the scheme applies along with the exceptions.

This patch changes the relevant feature bits from FTR_EXACT
to FTR_LOWER_SAFE to select the safer value. This will enable
an older kernel running on a new CPU detect the safer option
rather than completely disabling the feature.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Add support HiSilicon SoC uncore PMU driver.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

This patch adds support for DDRC PMU driver in HiSilicon SoC chip, Each
DDRC has own control, counter and interrupt registers and is an separate
PMU. For each DDRC PMU, it has 8-fixed-purpose counters which have been
mapped to 8-events by hardware, it assumes that counter index is equal
to event code (0 - 7) in DDRC PMU driver. Interrupt is supported to
handle counter (32-bits) overflow.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Signed-off-by: Anurup M <anurup.m@huawei.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

L3 cache coherence is maintained by Hydra Home Agent (HHA) in HiSilicon
SoC. This patch adds support for HHA PMU driver, Each HHA has own
control, counter and interrupt registers and is an separate PMU. For
each HHA PMU, it has 16-programable counters and each counter is
free-running. Interrupt is supported to handle counter (48-bits)
overflow.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Signed-off-by: Anurup M <anurup.m@huawei.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

This patch adds support for L3C PMU driver in HiSilicon SoC chip, Each
L3C has own control, counter and interrupt registers and is an separate
PMU. For each L3C PMU, it has 8-programable counters and each counter
is free-running. Interrupt is supported to handle counter (48-bits)
overflow.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Signed-off-by: Anurup M <anurup.m@huawei.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

This patch adds support HiSilicon SoC uncore PMU driver framework and
interfaces.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Signed-off-by: Anurup M <anurup.m@huawei.com>
[will: Fix leader accounting in uncore group validation]
Signed-off-by: Will Deacon <will.deacon@arm.com>

This patch adds documentation for the uncore PMUs on HiSilicon SoC.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Signed-off-by: Anurup M <anurup.m@huawei.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Based on: ARM Architecture Reference Manual, ARMv8 (DDI 0487B.b).

ARMv8.1 introduces the optional feature ARMv8.1-TTHM which can trigger a
new type of memory abort. This exception is triggered when hardware update
of page table flags is not atomic in regards to other memory accesses.
Replace the corresponding unknown entry with a more accurate one.

Cf: Section D10.2.28 ESR_ELx, Exception Syndrome Register (p D10-2381),
section D4.4.11 Restriction on memory types for hardware updates on page
tables (p D4-2116 - D4-2117).

ARMv8.2 does not add new exception types, however it is worth mentioning
that when obligatory feature RAS (optional for ARMv8.{0,1}) is implemented,
exceptions related to "Synchronous parity or ECC error on memory access,
not on translation table walk" become reserved and should not occur.
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

The ARMv8.2 architecture introduces the optional Statistical Profiling
Extension (SPE).

SPE can be used to profile a population of operations in the CPU pipeline
after instruction decode. These are either architected instructions (i.e.
a dynamic instruction trace) or CPU-specific uops and the choice is fixed
statically in the hardware and advertised to userspace via caps/. Sampling
is controlled using a sampling interval, similar to a regular PMU counter,
but also with an optional random perturbation to avoid falling into patterns
where you continuously profile the same instruction in a hot loop.

After each operation is decoded, the interval counter is decremented. When
it hits zero, an operation is chosen for profiling and tracked within the
pipeline until it retires. Along the way, information such as TLB lookups,
cache misses, time spent to issue etc is captured in the form of a sample.
The sample is then filtered according to certain criteria (e.g. load
latency) that can be specified in the event config (described under
format/) and, if the sample satisfies the filter, it is written out to
memory as a record, otherwise it is discarded. Only one operation can
be sampled at a time.

The in-memory buffer is linear and virtually addressed, raising an
interrupt when it fills up. The PMU driver handles these interrupts to
give the appearance of a ring buffer, as expected by the AUX code.

The in-memory trace-like format is self-describing (though not parseable
in reverse) and written as a series of records, with each record
corresponding to a sample and consisting of a sequence of packets. These
packets are defined by the architecture, although some have CPU-specific
fields for recording information specific to the microarchitecture.

As a simple example, a record generated for a branch instruction may
consist of the following packets:

  0 (Address) : Virtual PC of the branch instruction
  1 (Type)    : Conditional direct branch
  2 (Counter) : Number of cycles taken from Dispatch to Issue
  3 (Address) : Virtual branch target + condition flags
  4 (Counter) : Number of cycles taken from Dispatch to Complete
  5 (Events)  : Mispredicted as not-taken
  6 (END)     : End of record

It is also possible to toggle properties such as timestamp packets in
each record.

This patch adds support for SPE in the form of a new perf driver.

Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

This patch documents the devicetree binding in use for ARM SPE.

Cc: Rob Herring <robh@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

When booting at EL2, ensure that we permit the EL1 host to sample
physical addresses and physical counter values using SPE.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

SPE is part of the v8.2 architecture, so move its system register and
field definitions into sysreg.h and the new PSB barrier into barrier.h

Finally, move KVM over to using the generic definitions so that it
doesn't have to open-code its own versions.
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

The ARM SPE architecture permits an implementation to ignore a sample
if the sample is due to be taken whilst another sample is already being
produced. In this case, it is desirable to report the collision to
userspace, as they may want to lower the sample period.

This patch adds a PERF_AUX_FLAG_COLLISION flag, so that such events can
be relayed to userspace.
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Perf PMU drivers using AUX buffers cannot be built as modules unless
the AUX helpers are exported.

This patch exports perf_aux_output_{begin,end,skip} and perf_get_aux to
modules.

Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Any modular driver using cluster-affine PPIs needs to be able to call
irq_get_percpu_devid_partition so that it can enable the IRQ on the
correct subset of CPUs.

This patch exports the symbol so that it can be called from within a
module.
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Merge tag 'acpi/iort-for-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/lpieralisi/linux into aarch64/for-next/core

Pull arm64 ACPI IORT updates from Lorenzo Pieralisi:

- Code clean-ups (A.Yadav, L.Pieralisi)
- Platform devices inizialization rework in preparation for IORT PMCG
  handling (L.Pieralisi)
- Mapping API rework to enable MSIs for IORT components as defined in
  IORT specification issue C (H.Guo, L.Pieralisi)
Signed-off-by: Will Deacon <will.deacon@arm.com>

ITS specific mappings for SMMUv3/PMCG components can be retrieved
through special index mapping entries introduced in IORT revision C.

Introduce a new API iort_set_device_domain() to set the MSI domain for
SMMUv3/PMCG nodes (extendable to any future IORT node requiring special
index ITS mapping entries) that represent MSI through special index
mappings in order to enable MSI support for the devices their nodes
represent.
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>

IORT revision C introduced a mapping entry binding to describe ITS
device ID mapping for SMMUv3 MSI interrupts.

Enable the single mapping flag (ie that is used by SMMUv3 component for
its special index mappings) for the SMMUv3 node in the IORT mapping API
and add IORT code to handle special index mapping entry for the SMMUv3
IORT nodes to enable their MSI interrupts. In case the ACPICA for
SMMUv3 device ID mapping is not ready, use the ACPICA version as a guard
for function iort_get_id_mapping_index().
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
[lorenzo.pieralisi@arm.com: patch split, typos fixing, rewrote the log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

IORT revision C introduced SMMUv3 and PMCG MSI support by adding
specific mapping entries in the SMMUv3/PMCG subtables to retrieve
the device ID and the ITS group it maps to for a given SMMUv3/PMCG
IORT node.

Introduce a mapping function (ie iort_get_id_mapping_index()), that
for a given IORT node looks up if an ITS specific ID mapping entry
exists and if so retrieve the corresponding mapping index in the IORT
node mapping array.

Since an ITS specific index mapping can be present for an IORT
node that is not a leaf node (eg SMMUv3 - to describe its own
ITS device ID) special handling is required for two steps mapping
cases such as PCI/NamedComponent--->SMMUv3--->ITS because the SMMUv3
ITS specific index mapping entry should be skipped to prevent the
IORT API from considering the mapping entry as a regular mapping one.

If we take the following IORT topology example:

|----------------------|
|  Root Complex Node   |
|----------------------|
|    map entry[x]      |
|----------------------|
|       id value       |
| output_reference     |
|---|------------------|
    |
    |   |----------------------|
    |-->|        SMMUv3        |
        |----------------------|
        |     SMMUv3 dev ID    |
        |     mapping index 0  |
        |----------------------|
        |      map entry[0]    |
        |----------------------|
        |       id value       |
        | output_reference-----------> ITS 1 (SMMU MSI domain)
        |----------------------|
        |      map entry[1]    |
        |----------------------|
        |       id value       |
        | output_reference-----------> ITS 2 (PCI MSI domain)
        |----------------------|

where the SMMUv3 ITS specific mapping entry is index 0 and it
represents the SMMUv3 ITS specific index mapping entry (describing its
own ITS device ID), we need to skip that mapping entry while carrying
out the Root Complex Node regular mappings to prevent erroneous
translations.

Reuse the iort_get_id_mapping_index() function to detect the ITS
specific mapping index for a specific IORT node and skip it in the IORT
mapping API (ie iort_node_map_id()) loop to prevent considering it a
normal PCI/Named Component ID mapping entry.
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
[lorenzo.pieralisi@arm.com: split patch/rewrote commit log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Current IORT code provides a function (ie iort_get_fwnode())
which looks up a struct fwnode_handle pointer through a
struct acpi_iort_node pointer for SMMU components but it
lacks a function that implements the reverse look-up, namely
struct fwnode_handle* -> struct acpi_iort_node*.

Devices that are not IORT named components cannot be retrieved through
their associated IORT named component scan interface because they just
are not represented in the ACPI namespace; the reverse look-up is
therefore required for all platform devices that represent IORT nodes
(eg SMMUs) so that the struct acpi_iort_node* can be retrieved from the
struct device->fwnode pointer.
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
[lorenzo.pieralisi@arm.com: re-indented/rewrote the commit log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

The way current IORT code initializes platform devices for SMMU nodes
is somewhat tied (mostly for naming convention) to the SMMU nodes
themselves but it need not be in that it is completely generic and
can easily be made so by structures renaming and code reshuffling.

Rework IORT platform devices initialization code to make the functions
and data structures SMMU agnostic.

No functional changes intended.
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Sudeep Holla <sudeep.holla@arm.com>

Some functions definition indentations are using a style that is frowned
upon with return value type/storage class specifier in a separate line.

Reindent the function definitions to fix them.
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Sudeep Holla <sudeep.holla@arm.com>

The conditional ACPI_IORT_SMMU_V3_PXM_VALID guard around
arm_smmu_v3_set_proximity() was added to manage a cross tree
ACPICA merge dependency; with ACPICA changes merged in:

commit c9442300 ("ACPICA: iasl: Update to IORT SMMUv3
disassembling")

the guard has become useless. Remove it.
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com>

pr_err() messages should terminated with a new-line to avoid
other messages being concatenated onto the end.
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Hanjun Guo <hanjun.guo@linaro.org>

The current delay implementation uses the yield instruction, which is a
hint that it is beneficial to schedule another thread. As this is a hint,
it may be implemented as a NOP, causing all delays to be busy loops. This
is the case for many existing CPUs.

Taking advantage of the generic timer sending periodic events to all
cores, we can use WFE during delays to reduce power consumption. This is
beneficial only for delays longer than the period of the timer event
stream.

If timer event stream is not enabled, delays will behave as yield/busy
loops.
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

The arch timer configuration for a CPU might get reset after suspending
said CPU.

In order to reliably use the event stream in the kernel (e.g. for delays),
we keep track of the state where we can safely consider the event stream as
properly configured. After writing to cntkctl, we issue an ISB to ensure
that subsequent delay loops can rely on the event stream being enabled.
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

We don't document our ELF hwcaps, leaving developers to interpret them
according to hearsay, guesswork, or (in exceptional cases) inspection of
the current kernel code.

This is less than optimal, and it would be far better if we had some
definitive description of each of the ELF hwcaps that developers could
refer to.

This patch adds a document describing the (native) arm64 ELF hwcaps.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
[ Updated new hwcap entries in the document ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

ARMv8-A adds a few optional features for ARMv8.2 and ARMv8.3.
Expose them to the userspace via HWCAPs and mrs emulation.

SHA2-512  - Instruction support for SHA512 Hash algorithm (e.g SHA512H,
	    SHA512H2, SHA512U0, SHA512SU1)
SHA3 	  - SHA3 crypto instructions (EOR3, RAX1, XAR, BCAX).
SM3	  - Instruction support for Chinese cryptography algorithm SM3
SM4 	  - Instruction support for Chinese cryptography algorithm SM4
DP	  - Dot Product instructions (UDOT, SDOT).

Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Dave Martin <dave.martin@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Process personality always propagates across a fork(), but can change
at an execve().
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Will Deacon <will.deacon@arm.com>

For example on arm64 board, this add info to "user" entries in vmallocinfo

Before :
[...]
0xffffff8008997000 0xffffff80089d8000 266240 user
[...]

Afer :
[...]
0xffffff8008997000 0xffffff80089d8000 266240 atomic_pool_init+0x0/0x1d8 user
[...]

This help to debug mapping issues, and is consistent with others entries
(ioremap, vmalloc, ...) that already provide caller.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Matthieu CASTET <matthieu.castet@parrot.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

From what I can see there isn't anything about ACPI_APEI_SEA that
means the arm64 architecture can or cannot support NMI safe
cmpxchg or NMIs, so the 'if' condition here is not important.
Let's remove it. Doing that allows us to support ftrace
histograms via CONFIG_HIST_TRIGGERS that depends on the arch
having the ARCH_HAVE_NMI_SAFE_CMPXCHG config selected.

Cc: Tyler Baicar <tbaicar@codeaurora.org>
Cc: Jonathan (Zhixiong) Zhang <zjzhang@codeaurora.org>
Cc: Dongjiu Geng <gengdongjiu@huawei.com>
Acked-by: James Morse <james.morse@arm.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

acpi_disabled has been checked in armv8_pmu_driver_init and it shall
be ZERO in arm_pmu_acpi_probe, clean up this unnecessary check.
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Currently we inconsistently log identifying information for the boot CPU
and secondary CPUs. For the boot CPU, we log the MIDR and MPIDR across
separate messages, whereas for the secondary CPUs we only log the MIDR.

In some cases, it would be useful to know the MPIDR of secondary CPUs,
and it would be nice for these messages to be consistent.

This patch ensures that in the primary and secondary boot paths, we log
both the MPIDR and MIDR in a single message, with a consistent format.
the MPIDR is consistently padded to 10 hex characters to cover Aff3 in
bits 39:32, so that IDs can be compared easily.

The newly redundant message in setup_arch() is removed.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Al Stone <ahs3@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
[will: added '0x' prefixes consistently]
Signed-off-by: Will Deacon <will.deacon@arm.com>

Add event names so that common events can be
specified symbolically, for example:

l2cache_0/total-reads/,l2cache_0/cycles/

Event names are displayed in 'perf list'.
Signed-off-by: Neil Leeder <nleeder@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

As discussed at the Linux Security Summit, arm64 prefers to use
REFCOUNT_FULL by default. This enables it for the architecture.

Cc: hw.likun@huawei.com
Cc: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Use vma_pages function on vma object instead of explicit computation.
Found by coccinelle spatch "api/vma_pages.cocci"
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>

As you see in init/version.c, init_uts_ns.name.machine is initially
set to UTS_MACHINE.  There is no point to copy the same string.

I dug the git history to figure out why this line is here.  My best
guess is like this:

 - This line has been around here since the initial support of arm64
   by commit 9703d9d7 ("arm64: Kernel booting and initialisation").
   If ARCH (=arm64) and UTS_MACHINE (=aarch64) do not match,
   arch/$(ARCH)/Makefile is supposed to override UTS_MACHINE, but the
   initial version of arch/arm64/Makefile missed to do that.  Instead,
   the boot code copied "aarch64" to init_utsname()->machine.

 - Commit 94ed1f2c ("arm64: setup: report ELF_PLATFORM as the
   machine for utsname") replaced "aarch64" with ELF_PLATFORM to
   make "uname" to reflect the endianness.

 - ELF_PLATFORM does not help to provide the UTS machine name to rpm
   target, so commit cfa88c79 ("arm64: Set UTS_MACHINE in the
   Makefile") fixed it.  The commit simply replaced ELF_PLATFORM with
   UTS_MACHINE, but missed the fact the string copy itself is no longer
   needed.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>