linux-toradex.git/include/linux/arm-smccc.h, branch v6.6-rc5 Linux kernel for Apalis and Colibri modules KVM: arm64: nvhe: Ignore SVE hint in SMCCC function ID 2023-09-12T12:07:37+00:00 Jean-Philippe Brucker jean-philippe@linaro.org 2023-09-11T14:52:57+00:00 373beef00f7d781a000b12c31fb17a5a9c25969c When SVE is enabled, the host may set bit 16 in SMCCC function IDs, a hint that indicates an unused SVE state. At the moment NVHE doesn't account for this bit when inspecting the function ID, and rejects most calls. Clear the hint bit before comparing function IDs. About version compatibility: the host's PSCI driver initially probes the firmware for a SMCCC version number. If the firmware implements a protocol recent enough (1.3), subsequent SMCCC calls have the hint bit set. Since the hint bit was reserved in earlier versions of the protocol, clearing it is fine regardless of the version in use. When a new hint is added to the protocol in the future, it will be added to ARM_SMCCC_CALL_HINTS and NVHE will handle it straight away. This patch only clears known hints and leaves reserved bits as is, because future SMCCC versions could use reserved bits as modifiers for the function ID, rather than hints. Fixes: cfa7ff959a78 ("arm64: smccc: Support SMCCC v1.3 SVE register saving hint") Reported-by: Ben Horgan <ben.horgan@arm.com> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20230911145254.934414-4-jean-philippe@linaro.org 
When SVE is enabled, the host may set bit 16 in SMCCC function IDs, a
hint that indicates an unused SVE state. At the moment NVHE doesn't
account for this bit when inspecting the function ID, and rejects most
calls. Clear the hint bit before comparing function IDs.

About version compatibility: the host's PSCI driver initially probes the
firmware for a SMCCC version number. If the firmware implements a
protocol recent enough (1.3), subsequent SMCCC calls have the hint bit
set. Since the hint bit was reserved in earlier versions of the
protocol, clearing it is fine regardless of the version in use.

When a new hint is added to the protocol in the future, it will be added
to ARM_SMCCC_CALL_HINTS and NVHE will handle it straight away. This
patch only clears known hints and leaves reserved bits as is, because
future SMCCC versions could use reserved bits as modifiers for the
function ID, rather than hints.

Fixes: cfa7ff959a78 ("arm64: smccc: Support SMCCC v1.3 SVE register saving hint")
Reported-by: Ben Horgan <ben.horgan@arm.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230911145254.934414-4-jean-philippe@linaro.org
arm64: smccc: replace custom COUNT_ARGS() & CONCATENATE() implementations 2023-08-18T17:18:56+00:00 Andy Shevchenko andriy.shevchenko@linux.intel.com 2023-07-18T21:11:46+00:00 90e3e18548e6a8e9e66fe2b4f4ad62bd9e8f0cda Replace custom implementation of the macros from args.h. Link: https://lkml.kernel.org/r/20230718211147.18647-4-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Petkov (AMD) <bp@alien8.de> Cc: Brendan Higgins <brendan.higgins@linux.dev> Cc: Daniel Latypov <dlatypov@google.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Gow <davidgow@google.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lorenzo Pieralisi <lpieralisi@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Steven Rostedt (Google) <rostedt@goodmis.org> Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> 
Replace custom implementation of the macros from args.h.

Link: https://lkml.kernel.org/r/20230718211147.18647-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: Daniel Latypov <dlatypov@google.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Gow <davidgow@google.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lorenzo Pieralisi <lpieralisi@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
irqchip/gicv3: Workaround for NVIDIA erratum T241-FABRIC-4 2023-04-08T09:51:23+00:00 Shanker Donthineni sdonthineni@nvidia.com 2023-03-19T02:43:14+00:00 35727af2b15d98a2dd2811d631d3a3886111312e The T241 platform suffers from the T241-FABRIC-4 erratum which causes unexpected behavior in the GIC when multiple transactions are received simultaneously from different sources. This hardware issue impacts NVIDIA server platforms that use more than two T241 chips interconnected. Each chip has support for 320 {E}SPIs. This issue occurs when multiple packets from different GICs are incorrectly interleaved at the target chip. The erratum text below specifies exactly what can cause multiple transfer packets susceptible to interleaving and GIC state corruption. GIC state corruption can lead to a range of problems, including kernel panics, and unexpected behavior. >From the erratum text: "In some cases, inter-socket AXI4 Stream packets with multiple transfers, may be interleaved by the fabric when presented to ARM Generic Interrupt Controller. GIC expects all transfers of a packet to be delivered without any interleaving. The following GICv3 commands may result in multiple transfer packets over inter-socket AXI4 Stream interface: - Register reads from GICD_I* and GICD_N* - Register writes to 64-bit GICD registers other than GICD_IROUTERn* - ITS command MOVALL Multiple commands in GICv4+ utilize multiple transfer packets, including VMOVP, VMOVI, VMAPP, and 64-bit register accesses." This issue impacts system configurations with more than 2 sockets, that require multi-transfer packets to be sent over inter-socket AXI4 Stream interface between GIC instances on different sockets. GICv4 cannot be supported. GICv3 SW model can only be supported with the workaround. Single and Dual socket configurations are not impacted by this issue and support GICv3 and GICv4." Link: https://developer.nvidia.com/docs/t241-fabric-4/nvidia-t241-fabric-4-errata.pdf Writing to the chip alias region of the GICD_In{E} registers except GICD_ICENABLERn has an equivalent effect as writing to the global distributor. The SPI interrupt deactivate path is not impacted by the erratum. To fix this problem, implement a workaround that ensures read accesses to the GICD_In{E} registers are directed to the chip that owns the SPI, and disable GICv4.x features. To simplify code changes, the gic_configure_irq() function uses the same alias region for both read and write operations to GICD_ICFGR. Co-developed-by: Vikram Sethi <vsethi@nvidia.com> Signed-off-by: Vikram Sethi <vsethi@nvidia.com> Signed-off-by: Shanker Donthineni <sdonthineni@nvidia.com> Acked-by: Sudeep Holla <sudeep.holla@arm.com> (for SMCCC/SOC ID bits) Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20230319024314.3540573-2-sdonthineni@nvidia.com 
The T241 platform suffers from the T241-FABRIC-4 erratum which causes
unexpected behavior in the GIC when multiple transactions are received
simultaneously from different sources. This hardware issue impacts
NVIDIA server platforms that use more than two T241 chips
interconnected. Each chip has support for 320 {E}SPIs.

This issue occurs when multiple packets from different GICs are
incorrectly interleaved at the target chip. The erratum text below
specifies exactly what can cause multiple transfer packets susceptible
to interleaving and GIC state corruption. GIC state corruption can
lead to a range of problems, including kernel panics, and unexpected
behavior.

>From the erratum text:
  "In some cases, inter-socket AXI4 Stream packets with multiple
  transfers, may be interleaved by the fabric when presented to ARM
  Generic Interrupt Controller. GIC expects all transfers of a packet
  to be delivered without any interleaving.

  The following GICv3 commands may result in multiple transfer packets
  over inter-socket AXI4 Stream interface:
   - Register reads from GICD_I* and GICD_N*
   - Register writes to 64-bit GICD registers other than GICD_IROUTERn*
   - ITS command MOVALL

  Multiple commands in GICv4+ utilize multiple transfer packets,
  including VMOVP, VMOVI, VMAPP, and 64-bit register accesses."

  This issue impacts system configurations with more than 2 sockets,
  that require multi-transfer packets to be sent over inter-socket
  AXI4 Stream interface between GIC instances on different sockets.
  GICv4 cannot be supported. GICv3 SW model can only be supported
  with the workaround. Single and Dual socket configurations are not
  impacted by this issue and support GICv3 and GICv4."

Link: https://developer.nvidia.com/docs/t241-fabric-4/nvidia-t241-fabric-4-errata.pdf

Writing to the chip alias region of the GICD_In{E} registers except
GICD_ICENABLERn has an equivalent effect as writing to the global
distributor. The SPI interrupt deactivate path is not impacted by
the erratum.

To fix this problem, implement a workaround that ensures read accesses
to the GICD_In{E} registers are directed to the chip that owns the
SPI, and disable GICv4.x features. To simplify code changes, the
gic_configure_irq() function uses the same alias region for both read
and write operations to GICD_ICFGR.

Co-developed-by: Vikram Sethi <vsethi@nvidia.com>
Signed-off-by: Vikram Sethi <vsethi@nvidia.com>
Signed-off-by: Shanker Donthineni <sdonthineni@nvidia.com>
Acked-by: Sudeep Holla <sudeep.holla@arm.com> (for SMCCC/SOC ID bits)
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230319024314.3540573-2-sdonthineni@nvidia.com
arm64: entry: Add vectors that have the bhb mitigation sequences 2022-02-16T13:16:08+00:00 James Morse james.morse@arm.com 2021-11-18T13:59:46+00:00 ba2689234be92024e5635d30fe744f4853ad97db Some CPUs affected by Spectre-BHB need a sequence of branches, or a firmware call to be run before any indirect branch. This needs to go in the vectors. No CPU needs both. While this can be patched in, it would run on all CPUs as there is a single set of vectors. If only one part of a big/little combination is affected, the unaffected CPUs have to run the mitigation too. Create extra vectors that include the sequence. Subsequent patches will allow affected CPUs to select this set of vectors. Later patches will modify the loop count to match what the CPU requires. Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: James Morse <james.morse@arm.com> 
Some CPUs affected by Spectre-BHB need a sequence of branches, or a
firmware call to be run before any indirect branch. This needs to go
in the vectors. No CPU needs both.

While this can be patched in, it would run on all CPUs as there is a
single set of vectors. If only one part of a big/little combination is
affected, the unaffected CPUs have to run the mitigation too.

Create extra vectors that include the sequence. Subsequent patches will
allow affected CPUs to select this set of vectors. Later patches will
modify the loop count to match what the CPU requires.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
qcom_scm: hide Kconfig symbol 2021-10-07T14:51:57+00:00 Arnd Bergmann arnd@arndb.de 2021-09-28T07:50:27+00:00 424953cf3c6657f1e67e1a2c5d6e3bb518ea4e9a Now that SCM can be a loadable module, we have to add another dependency to avoid link failures when ipa or adreno-gpu are built-in: aarch64-linux-ld: drivers/net/ipa/ipa_main.o: in function `ipa_probe': ipa_main.c:(.text+0xfc4): undefined reference to `qcom_scm_is_available' ld.lld: error: undefined symbol: qcom_scm_is_available >>> referenced by adreno_gpu.c >>> gpu/drm/msm/adreno/adreno_gpu.o:(adreno_zap_shader_load) in archive drivers/built-in.a This can happen when CONFIG_ARCH_QCOM is disabled and we don't select QCOM_MDT_LOADER, but some other module selects QCOM_SCM. Ideally we'd use a similar dependency here to what we have for QCOM_RPROC_COMMON, but that causes dependency loops from other things selecting QCOM_SCM. This appears to be an endless problem, so try something different this time: - CONFIG_QCOM_SCM becomes a hidden symbol that nothing 'depends on' but that is simply selected by all of its users - All the stubs in include/linux/qcom_scm.h can go away - arm-smccc.h needs to provide a stub for __arm_smccc_smc() to allow compile-testing QCOM_SCM on all architectures. - To avoid a circular dependency chain involving RESET_CONTROLLER and PINCTRL_SUNXI, drop the 'select RESET_CONTROLLER' statement. According to my testing this still builds fine, and the QCOM platform selects this symbol already. Acked-by: Kalle Valo <kvalo@codeaurora.org> Acked-by: Alex Elder <elder@linaro.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de> 
Now that SCM can be a loadable module, we have to add another
dependency to avoid link failures when ipa or adreno-gpu are
built-in:

aarch64-linux-ld: drivers/net/ipa/ipa_main.o: in function `ipa_probe':
ipa_main.c:(.text+0xfc4): undefined reference to `qcom_scm_is_available'

ld.lld: error: undefined symbol: qcom_scm_is_available
>>> referenced by adreno_gpu.c
>>>               gpu/drm/msm/adreno/adreno_gpu.o:(adreno_zap_shader_load) in archive drivers/built-in.a

This can happen when CONFIG_ARCH_QCOM is disabled and we don't select
QCOM_MDT_LOADER, but some other module selects QCOM_SCM. Ideally we'd
use a similar dependency here to what we have for QCOM_RPROC_COMMON,
but that causes dependency loops from other things selecting QCOM_SCM.

This appears to be an endless problem, so try something different this
time:

 - CONFIG_QCOM_SCM becomes a hidden symbol that nothing 'depends on'
   but that is simply selected by all of its users

 - All the stubs in include/linux/qcom_scm.h can go away

 - arm-smccc.h needs to provide a stub for __arm_smccc_smc() to
   allow compile-testing QCOM_SCM on all architectures.

 - To avoid a circular dependency chain involving RESET_CONTROLLER
   and PINCTRL_SUNXI, drop the 'select RESET_CONTROLLER' statement.
   According to my testing this still builds fine, and the QCOM
   platform selects this symbol already.

Acked-by: Kalle Valo <kvalo@codeaurora.org>
Acked-by: Alex Elder <elder@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
arm64: smccc: Support SMCCC v1.3 SVE register saving hint 2021-06-08T13:00:12+00:00 Mark Brown broonie@kernel.org 2021-06-03T18:41:18+00:00 cfa7ff959a789a953eac40c8ac793e2cfc2db931 SMCCC v1.2 requires that all SVE state be preserved over SMC calls which introduces substantial overhead in the common case where there is no SVE state in the registers. To avoid this SMCCC v1.3 introduces a flag which allows the caller to say that there is no state that needs to be preserved in the registers. Make use of this flag, setting it if the SMCCC version indicates support for it and the TIF_ flags indicate that there is no live SVE state in the registers, this avoids placing any constraints on when SMCCC calls can be done or triggering extra saving and reloading of SVE register state in the kernel. This would be straightforward enough except for the rather entertaining inline assembly we use to do SMCCC v1.1 calls to allow us to take advantage of the limited number of registers it clobbers. Deal with this by having a function which we call immediately before issuing the SMCCC call to make our checks and set the flag. Using alternatives the overhead if SVE is supported but not detected at runtime can be reduced to a single NOP. Signed-off-by: Mark Brown <broonie@kernel.org> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210603184118.15090-1-broonie@kernel.org Signed-off-by: Will Deacon <will@kernel.org> 
SMCCC v1.2 requires that all SVE state be preserved over SMC calls which
introduces substantial overhead in the common case where there is no SVE
state in the registers. To avoid this SMCCC v1.3 introduces a flag which
allows the caller to say that there is no state that needs to be preserved
in the registers. Make use of this flag, setting it if the SMCCC version
indicates support for it and the TIF_ flags indicate that there is no live
SVE state in the registers, this avoids placing any constraints on when
SMCCC calls can be done or triggering extra saving and reloading of SVE
register state in the kernel.

This would be straightforward enough except for the rather entertaining
inline assembly we use to do SMCCC v1.1 calls to allow us to take advantage
of the limited number of registers it clobbers. Deal with this by having a
function which we call immediately before issuing the SMCCC call to make
our checks and set the flag. Using alternatives the overhead if SVE is
supported but not detected at runtime can be reduced to a single NOP.

Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210603184118.15090-1-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
arm64: smccc: Add support for SMCCCv1.2 extended input/output registers 2021-05-26T16:14:09+00:00 Sudeep Holla sudeep.holla@arm.com 2021-05-18T16:36:18+00:00 3fdc0cb59d97f87e2cc708d424f1538e31744286 SMCCC v1.2 allows x8-x17 to be used as parameter registers and x4—x17 to be used as result registers in SMC64/HVC64. Arm Firmware Framework for Armv8-A specification makes use of x0-x7 as parameter and result registers. There are other users like Hyper-V who intend to use beyond x0-x7 as well. Current SMCCC interface in the kernel just use x0-x7 as parameter and x0-x3 as result registers as required by SMCCCv1.0. Let us add new interface to support this extended set of input/output registers namely x0-x17 as both parameter and result registers. Acked-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Michael Kelley <mikelley@microsoft.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Cc: Will Deacon <will@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Reviewed-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20210518163618.43950-1-sudeep.holla@arm.com Signed-off-by: Will Deacon <will@kernel.org> 
SMCCC v1.2 allows x8-x17 to be used as parameter registers and x4—x17
to be used as result registers in SMC64/HVC64. Arm Firmware Framework
for Armv8-A specification makes use of x0-x7 as parameter and result
registers. There are other users like Hyper-V who intend to use beyond
x0-x7 as well.

Current SMCCC interface in the kernel just use x0-x7 as parameter and
x0-x3 as result registers as required by SMCCCv1.0. Let us add new
interface to support this extended set of input/output registers namely
x0-x17 as both parameter and result registers.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210518163618.43950-1-sudeep.holla@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
KVM: arm64: Add support for the KVM PTP service 2021-04-07T15:33:20+00:00 Jianyong Wu jianyong.wu@arm.com 2020-12-09T06:09:29+00:00 3bf725699bf62494b3e179f1795f08c7d749f061 Implement the hypervisor side of the KVM PTP interface. The service offers wall time and cycle count from host to guest. The caller must specify whether they want the host's view of either the virtual or physical counter. Signed-off-by: Jianyong Wu <jianyong.wu@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20201209060932.212364-7-jianyong.wu@arm.com 
Implement the hypervisor side of the KVM PTP interface.

The service offers wall time and cycle count from host to guest.
The caller must specify whether they want the host's view of
either the virtual or physical counter.

Signed-off-by: Jianyong Wu <jianyong.wu@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201209060932.212364-7-jianyong.wu@arm.com
arm/arm64: Probe for the presence of KVM hypervisor 2021-03-31T08:16:55+00:00 Will Deacon will@kernel.org 2020-12-09T06:09:24+00:00 6e085e0ac9cf16298b5fefe0b1893f98ef765812 Although the SMCCC specification provides some limited functionality for describing the presence of hypervisor and firmware services, this is generally applicable only to functions designated as "Arm Architecture Service Functions" and no portable discovery mechanism is provided for standard hypervisor services, despite having a designated range of function identifiers reserved by the specification. In an attempt to avoid the need for additional firmware changes every time a new function is added, introduce a UID to identify the service provider as being compatible with KVM. Once this has been established, additional services can be discovered via a feature bitmap. Reviewed-by: Steven Price <steven.price@arm.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Jianyong Wu <jianyong.wu@arm.com> [maz: move code to its own file, plug it into PSCI] Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20201209060932.212364-2-jianyong.wu@arm.com 
Although the SMCCC specification provides some limited functionality for
describing the presence of hypervisor and firmware services, this is
generally applicable only to functions designated as "Arm Architecture
Service Functions" and no portable discovery mechanism is provided for
standard hypervisor services, despite having a designated range of
function identifiers reserved by the specification.

In an attempt to avoid the need for additional firmware changes every
time a new function is added, introduce a UID to identify the service
provider as being compatible with KVM. Once this has been established,
additional services can be discovered via a feature bitmap.

Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Jianyong Wu <jianyong.wu@arm.com>
[maz: move code to its own file, plug it into PSCI]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201209060932.212364-2-jianyong.wu@arm.com
firmware: smccc: Add SMCCC TRNG function call IDs 2021-01-20T12:31:43+00:00 Ard Biesheuvel ardb@kernel.org 2021-01-06T10:34:49+00:00 67c6bb56b649590a3f59c2a92331aa4e83d4534c The ARM architected TRNG firmware interface, described in ARM spec DEN0098, define an ARM SMCCC based interface to a true random number generator, provided by firmware. Add the definitions of the SMCCC functions as defined by the spec. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Andre Przywara <andre.przywara@arm.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com> Link: https://lore.kernel.org/r/20210106103453.152275-2-andre.przywara@arm.com Signed-off-by: Will Deacon <will@kernel.org> 
The ARM architected TRNG firmware interface, described in ARM spec
DEN0098, define an ARM SMCCC based interface to a true random number
generator, provided by firmware.

Add the definitions of the SMCCC functions as defined by the spec.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Link: https://lore.kernel.org/r/20210106103453.152275-2-andre.przywara@arm.com
Signed-off-by: Will Deacon <will@kernel.org>