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Convert CLIDR_EL1 to be automatically generated with definition as per
DDI0487H.a. No functional change.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220520161639.324236-2-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Convert the various ZCR instances to automatic generation, no functional
changes expected.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220510161208.631259-13-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Convert SVCR to automatic generation, no functional change.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220510161208.631259-12-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Convert SMPRI_EL1 to be generated. No functional change.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220510161208.631259-11-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
No functional change should be seen from converting SMPRIMAP_EL2 to be
generated.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220510161208.631259-10-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Automatically generate the defines for SMIDR_EL1, no functional change.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220510161208.631259-9-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Convert SMCR to use the register definition code, no functional change.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220510161208.631259-8-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Add a statement for RAZ bitfields to the automatic register generation
script. Nothing is emitted to the header for these fields.
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220510161208.631259-7-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The defines for SVCR call it SVCR_EL0 however the architecture calls the
register SVCR with no _EL0 suffix. In preparation for generating the sysreg
definitions rename to match the architecture, no functional change.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220510161208.631259-6-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The bitfield definitions for SVCR have a SYS_ added to the names of the
constant which will be a problem for automatic generation. Remove the
prefixes, no functional change.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220510161208.631259-5-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
We currently have a non-standard SYS_ prefix in the constants generated
for SMIDR_EL1 bitfields. Drop this in preparation for automatic register
definition generation, no functional change.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220510161208.631259-4-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The SVE and SVE length configuration field LEN have constants specifying
their width called _SIZE rather than the more normal _WIDTH, in preparation
for automatic generation rename to _WIDTH. No functional change.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220510161208.631259-3-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Currently (as of DDI0487H.a) the architecture defines the vector length
control field in ZCR and SMCR as being 4 bits wide with an additional 5
bits reserved above it marked as RAZ/WI for future expansion. The kernel
currently attempts to anticipate such expansion by treating these extra
bits as part of the LEN field but this will be inconvenient when we start
generating the defines and would cause problems in the event that the
architecture goes a different direction with these fields. Let's instead
change the defines to reflect the currently defined architecture, we can
update in future as needed.
No change in behaviour should be seen in any system, even emulated systems
using the maximum allowed vector length for the current architecture.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220510161208.631259-2-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* for-next/sme: (29 commits)
: Scalable Matrix Extensions support.
arm64/sve: Make kernel FPU protection RT friendly
arm64/sve: Delay freeing memory in fpsimd_flush_thread()
arm64/sme: More sensibly define the size for the ZA register set
arm64/sme: Fix NULL check after kzalloc
arm64/sme: Add ID_AA64SMFR0_EL1 to __read_sysreg_by_encoding()
arm64/sme: Provide Kconfig for SME
KVM: arm64: Handle SME host state when running guests
KVM: arm64: Trap SME usage in guest
KVM: arm64: Hide SME system registers from guests
arm64/sme: Save and restore streaming mode over EFI runtime calls
arm64/sme: Disable streaming mode and ZA when flushing CPU state
arm64/sme: Add ptrace support for ZA
arm64/sme: Implement ptrace support for streaming mode SVE registers
arm64/sme: Implement ZA signal handling
arm64/sme: Implement streaming SVE signal handling
arm64/sme: Disable ZA and streaming mode when handling signals
arm64/sme: Implement traps and syscall handling for SME
arm64/sme: Implement ZA context switching
arm64/sme: Implement streaming SVE context switching
arm64/sme: Implement SVCR context switching
...
Non RT kernels need to protect FPU against preemption and bottom half
processing. This is achieved by disabling bottom halves via
local_bh_disable() which implictly disables preemption.
On RT kernels this protection mechanism is not sufficient because
local_bh_disable() does not disable preemption. It serializes bottom half
related processing via a CPU local lock.
As bottom halves are running always in thread context on RT kernels
disabling preemption is the proper choice as it implicitly prevents bottom
half processing.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220505163207.85751-3-bigeasy@linutronix.de
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
fpsimd_flush_thread() invokes kfree() via sve_free()+sme_free() within a
preempt disabled section which is not working on -RT.
Delay freeing of memory until preemption is enabled again.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220505163207.85751-2-bigeasy@linutronix.de
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Between the header and the definitions, there's no line gap, and in a
couple of places a double line gap for no semantic reason, which makes
the output look a little odd.
Fix this so blocks are consistently separated with a single line gap:
* Add a newline after the "Generated file" comment line, so this is
clearly split from whatever the first definition in the file is.
* At the start of a SysregFields block there's no need for a newline as
we haven't output any sysreg encoding details prior to this.
* At the end of a Sysreg block there's no need for a newline if we
have no RES0 or RES1 fields, as there will be a line gap after the
previous element (e.g. a Fields line).
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20220513174118.266966-3-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Currently for registers without fields we create a comment pointing at
the common definitions, e.g.
| #define REG_TTBR0_EL1 S3_0_C2_C0_0
| #define SYS_TTBR0_EL1 sys_reg(3, 0, 2, 0, 0)
| #define SYS_TTBR0_EL1_Op0 3
| #define SYS_TTBR0_EL1_Op1 0
| #define SYS_TTBR0_EL1_CRn 2
| #define SYS_TTBR0_EL1_CRm 0
| #define SYS_TTBR0_EL1_Op2 0
|
| /* See TTBRx_EL1 */
It would be slightly nicer if the comment said what we should be looking
for, e.g.
| #define REG_TTBR0_EL1 S3_0_C2_C0_0
| #define SYS_TTBR0_EL1 sys_reg(3, 0, 2, 0, 0)
| #define SYS_TTBR0_EL1_Op0 3
| #define SYS_TTBR0_EL1_Op1 0
| #define SYS_TTBR0_EL1_CRn 2
| #define SYS_TTBR0_EL1_CRm 0
| #define SYS_TTBR0_EL1_Op2 0
|
| /* For TTBR0_EL1 fields see TTBRx_EL1 */
Update the comment generation accordingly.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20220513174118.266966-2-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Since the vector length configuration mechanism is identical between SVE
and SME we share large elements of the code including the definition for
the maximum vector length. Unfortunately when we were defining the ABI
for SVE we included not only the actual maximum vector length of 2048
bits but also the value possible if all the bits reserved in the
architecture for expansion of the LEN field were used, 16384 bits.
This starts creating problems if we try to allocate anything for the ZA
matrix based on the maximum possible vector length, as we do for the
regset used with ptrace during the process of generating a core dump.
While the maximum potential size for ZA with the current architecture is
a reasonably managable 64K with the higher reserved limit ZA would be
64M which leads to entirely reasonable complaints from the memory
management code when we try to allocate a buffer of that size. Avoid
these issues by defining the actual maximum vector length for the
architecture and using it for the SME regsets.
Also use the full ZA_PT_SIZE() with the header rather than just the
actual register payload when specifying the size, fixing support for the
largest vector lengths now that we have this new, lower define. With the
SVE maximum this did not cause problems due to the extra headroom we
had.
While we're at it add a comment clarifying why even though ZA is a
single register we tell the regset code that it is a multi-register
regset.
Reported-by: Qian Cai <quic_qiancai@quicinc.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Link: https://lore.kernel.org/r/20220505221517.1642014-1-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Automatically generate register definitions for SCTLR_EL1. No functional
change.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220503170233.507788-13-broonie@kernel.org
[catalin.marinas@arm.com: fix the SCTLR_EL1 encoding]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Automatically generate definitions for accessing the TTBRn_EL1 registers,
no functional change.
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220503170233.507788-12-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Remove the manual definitions for ID_AA64ISAR0_EL1 in favour of automatic
generation. There should be no functional change. The only notable change
is that 27:24 TME is defined rather than RES0 reflecting DDI0487H.a.
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220503170233.507788-11-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Now that we have a script for generating system registers hook it up to the
build system similarly to cpucaps. Since we don't currently have any actual
register information in the input file this should produce no change in the
built kernel. For ease of review the register information will be converted
in separate patches.
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220503170233.507788-10-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The arm64 kernel requires some metadata for each system register it may
need to access. Currently we have:
* A SYS_<regname> definition which sorresponds to a sys_reg() macro.
This is used both to look up a sysreg by encoding (e.g. in KVM), and
also to generate code to access a sysreg where the assembler is
unaware of the specific sysreg encoding.
Where assemblers support the S3_<op1>_C<crn>_C<crm>_<op2> syntax for
system registers, we could use this rather than manually assembling
the instructions. However, we don't have consistent definitions for
these and we currently still need to handle toolchains that lack this
feature.
* A set of <regname>_<fieldname>_SHIFT and <regname>_<fieldname>_MASK
definitions, which can be used to extract fields from the register, or
to construct a register from a set of fields.
These do not follow the convention used by <linux/bitfield.h>, and the
masks are not shifted into place, preventing their use in FIELD_PREP()
and FIELD_GET(). We require the SHIFT definitions for inline assembly
(and WIDTH definitions would be helpful for UBFX/SBFX), so we cannot
only define a shifted MASK. Defining a SHIFT, WIDTH, shifted MASK and
unshifted MASK is tedious and error-prone and life is much easier when
they can be relied up to exist when writing code.
* A set of <regname>_<fieldname>_<valname> definitions for each
enumerated value a field may hold. These are used when identifying the
presence of features.
Atop of this, other code has to build up metadata at runtime (e.g. the
sets of RES0/RES1 bits in a register).
This patch adds scripting so that we can have an easier-to-manage
canonical representation of this metadata, from which we can generate
all the definitions necessary for various use-cases, e.g.
| #define REG_ID_AA64ISAR0_EL1 S3_0_C0_C6_0
| #define SYS_ID_AA64ISAR0_EL1 sys_reg(3, 0, 0, 6, 0)
| #define SYS_ID_AA64ISAR0_EL1_Op0 3
| #define SYS_ID_AA64ISAR0_EL1_Op1 0
| #define SYS_ID_AA64ISAR0_EL1_CRn 0
| #define SYS_ID_AA64ISAR0_EL1_CRm 6
| #define SYS_ID_AA64ISAR0_EL1_Op2 0
| #define ID_AA64ISAR0_EL1_RNDR GENMASK(63, 60)
| #define ID_AA64ISAR0_EL1_RNDR_MASK GENMASK(63, 60)
| #define ID_AA64ISAR0_EL1_RNDR_SHIFT 60
| #define ID_AA64ISAR0_EL1_RNDR_WIDTH 4
| #define ID_AA64ISAR0_EL1_RNDR_NI UL(0b0000)
| #define ID_AA64ISAR0_EL1_RNDR_IMP UL(0b0001)
The script requires that all bits in the register be specified and that
there be no overlapping fields. This helps the script spot errors in the
input but means that the few registers which change layout at runtime
depending on things like virtualisation settings will need some manual
handling. No actual register conversions are done here but a header for
the register data with some documention of the format is provided.
For cases where multiple registers share a layout (eg, when identical
controls are provided at multiple ELs) the register fields can be
defined once and referenced from the actual registers, currently we do
not generate actual defines for the individual registers.
At the moment this is only intended to express metadata from the
architecture, and does not handle policy imposed by the kernel, such as
values exposed to userspace or VMs. In future this could be extended to
express such information.
This script was mostly written by Mark Rutland but has been extended by
Mark Brown to improve validation of input and better integrate with the
kernel.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Co-Developed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220503170233.507788-9-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The macros for accessing fields in ID_AA64ISAR0_EL1 omit the _EL1 from the
name of the register. In preparation for converting this register to be
automatically generated update the names to include an _EL1, there should
be no functional change.
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220503170233.507788-8-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The architecture reference manual refers to the field in bits 23:20 of
ID_AA64ISAR0_EL1 with the name "atomic" but the kernel defines for this
bitfield use the name "atomics". Bring the two into sync to make it easier
to cross reference with the specification.
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220503170233.507788-7-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
In older revisions of the architecture SCTLR_EL1 contained several RES1
fields but in DDI0487H.a these now all have assigned functions. In
preparation for automatically generating sysreg.h provide explicit
definitions for all these bits and use them in the INIT_SCTLR_EL1_ macros
where _RES1 was previously used.
There should be no functional change.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220503170233.507788-6-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
We already use lower case in some defines in sysreg.h, for consistency with
the architecture definition do so for SCTLR_EL1.nTWE and SCTLR_EL1.nTWI.
No functional change.
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220503170233.507788-5-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
In preparation for automatic generation of the defines for system registers
make the values used for the enumeration in SCTLR_ELx.TCF suitable for use
with the newly defined SYS_FIELD_PREP_ENUM helper, removing the shift from
the define and using the helper to generate it on use instead. Since we
only ever interact with this field in EL1 and in preparation for generation
of the defines also rename from SCTLR_ELx to SCTLR_EL1. SCTLR_EL2 is not
quite the same as SCTLR_EL1 so the conversion does not share the field
definitions.
There should be no functional change from this patch.
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220503170233.507788-4-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
In preparation for automatic generation of SCTLR_EL1 register definitions
make the macros used to define SCTLR_EL1.TCF0 and the enumeration values it
has more standard so they can be used with FIELD_PREP() via the newly
defined SYS_FIELD_PREP_ helpers.
Since the field also exists in SCTLR_EL2 with the same values also rename
the macros to SCTLR_ELx rather than SCTLR_EL1.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com
Link: https://lore.kernel.org/r/20220503170233.507788-3-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The macros we define for the bitfields within sysregs have very regular
names, especially once we switch to automatic generation of those macros.
Take advantage of this to define wrappers around FIELD_PREP() allowing
us to simplify setting values in fields either numerically
SYS_FIELD_PREP(SCTLR_EL1, TCF0, 0x0)
or using the values of enumerations within the fields
SYS_FIELD_PREP_ENUM(SCTLR_EL1, TCF0, ASYMM)
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220503170233.507788-2-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Fix following coccicheck error:
./arch/arm64/kernel/process.c:322:2-23: alloc with no test, possible model on line 326
Here should be dst->thread.sve_state.
Fixes: 8bd7f91c03d8 ("arm64/sme: Implement traps and syscall handling for SME")
Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Reviwed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220426113054.630983-1-wanjiabing@vivo.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
We need to explicitly enumerate all the ID registers which we rely on
for CPU capabilities in __read_sysreg_by_encoding(), ID_AA64SMFR0_EL1 was
missed from this list so we trip a BUG() in paths which rely on that
function such as CPU hotplug. Add the register.
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20220427130828.162615-1-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Now that basline support for the Scalable Matrix Extension (SME) is present
introduce the Kconfig option allowing it to be built. While the feature
registers don't impose a strong requirement for a system with SME to
support SVE at runtime the support for streaming mode SVE is mostly
shared with normal SVE so depend on SVE.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-28-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
While we don't currently support SME in guests we do currently support it
for the host system so we need to take care of SME's impact, including
the floating point register state, when running guests. Simiarly to SVE
we need to manage the traps in CPACR_RL1, what is new is the handling of
streaming mode and ZA.
Normally we defer any handling of the floating point register state until
the guest first uses it however if the system is in streaming mode FPSIMD
and SVE operations may generate SME traps which we would need to distinguish
from actual attempts by the guest to use SME. Rather than do this for the
time being if we are in streaming mode when entering the guest we force
the floating point state to be saved immediately and exit streaming mode,
meaning that the guest won't generate SME traps for supported operations.
We could handle ZA in the access trap similarly to the FPSIMD/SVE state
without the disruption caused by streaming mode but for simplicity
handle it the same way as streaming mode for now.
This will be revisited when we support SME for guests (hopefully before SME
hardware becomes available), for now it will only incur additional cost on
systems with SME and even there only if streaming mode or ZA are enabled.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220419112247.711548-27-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
SME defines two new traps which need to be enabled for guests to ensure
that they can't use SME, one for the main SME operations which mirrors the
traps for SVE and another for access to TPIDR2 in SCTLR_EL2.
For VHE manage SMEN along with ZEN in activate_traps() and the FP state
management callbacks, along with SCTLR_EL2.EnTPIDR2. There is no
existing dynamic management of SCTLR_EL2.
For nVHE manage TSM in activate_traps() along with the fine grained
traps for TPIDR2 and SMPRI. There is no existing dynamic management of
fine grained traps.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220419112247.711548-26-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
For the time being we do not support use of SME by KVM guests, support for
this will be enabled in future. In order to prevent any side effects or
side channels via the new system registers, including the EL0 read/write
register TPIDR2, explicitly undefine all the system registers added by
SME and mask out the SME bitfield in SYS_ID_AA64PFR1.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220419112247.711548-25-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
When saving and restoring the floating point state over an EFI runtime
call ensure that we handle streaming mode, only handling FFR if we are not
in streaming mode and ensuring that we are in normal mode over the call
into runtime services.
We currently assume that ZA will not be modified by runtime services, the
specification is not yet finalised so this may need updating if that
changes.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-24-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Both streaming mode and ZA may increase power consumption when they are
enabled and streaming mode makes many FPSIMD and SVE instructions undefined
which will cause problems for any kernel mode floating point so disable
both when we flush the CPU state. This covers both kernel_neon_begin() and
idle and after flushing the state a reload is always required anyway.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-23-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The ZA array can be read and written with the NT_ARM_ZA. Similarly to
our interface for the SVE vector registers the regset consists of a
header with information on the current vector length followed by an
optional register data payload, represented as for signals as a series
of horizontal vectors from 0 to VL/8 in the endianness independent
format used for vectors.
On get if ZA is enabled then register data will be provided, otherwise
it will be omitted. On set if register data is provided then ZA is
enabled and initialized using the provided data, otherwise it is
disabled.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-22-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The streaming mode SVE registers are represented using the same data
structures as for SVE but since the vector lengths supported and in use
may not be the same as SVE we represent them with a new type NT_ARM_SSVE.
Unfortunately we only have a single 16 bit reserved field available in
the header so there is no space to fit the current and maximum vector
length for both standard and streaming SVE mode without redefining the
structure in a way the creates a complicatd and fragile ABI. Since FFR
is not present in streaming mode it is read and written as zero.
Setting NT_ARM_SSVE registers will put the task into streaming mode,
similarly setting NT_ARM_SVE registers will exit it. Reads that do not
correspond to the current mode of the task will return the header with
no register data. For compatibility reasons on write setting no flag for
the register type will be interpreted as setting SVE registers, though
users can provide no register data as an alternative mechanism for doing
so.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-21-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Implement support for ZA in signal handling in a very similar way to how
we implement support for SVE registers, using a signal context structure
with optional register state after it. Where present this register state
stores the ZA matrix as a series of horizontal vectors numbered from 0 to
VL/8 in the endinanness independent format used for vectors.
As with SVE we do not allow changes in the vector length during signal
return but we do allow ZA to be enabled or disabled.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-20-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
When in streaming mode we have the same set of SVE registers as we do in
regular SVE mode with the exception of FFR and the use of the SME vector
length. Provide signal handling for these registers by taking one of the
reserved words in the SVE signal context as a flags field and defining a
flag which is set for streaming mode. When the flag is set the vector
length is set to the streaming mode vector length and we save and
restore streaming mode data. We support entering or leaving streaming
mode based on the value of the flag but do not support changing the
vector length, this is not currently supported SVE signal handling.
We could instead allocate a separate record in the signal frame for the
streaming mode SVE context but this inflates the size of the maximal signal
frame required and adds complication when validating signal frames from
userspace, especially given the current structure of the code.
Any implementation of support for streaming mode vectors in signals will
have some potential for causing issues for applications that attempt to
handle SVE vectors in signals, use streaming mode but do not understand
streaming mode in their signal handling code, it is hard to identify a
case that is clearly better than any other - they all have cases where
they could cause unexpected register corruption or faults.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-19-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The ABI requires that streaming mode and ZA are disabled when invoking
signal handlers, do this in setup_return() when we prepare the task state
for the signal handler.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-18-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
By default all SME operations in userspace will trap. When this happens
we allocate storage space for the SME register state, set up the SVE
registers and disable traps. We do not need to initialize ZA since the
architecture guarantees that it will be zeroed when enabled and when we
trap ZA is disabled.
On syscall we exit streaming mode if we were previously in it and ensure
that all but the lower 128 bits of the registers are zeroed while
preserving the state of ZA. This follows the aarch64 PCS for SME, ZA
state is preserved over a function call and streaming mode is exited.
Since the traps for SME do not distinguish between streaming mode SVE
and ZA usage if ZA is in use rather than reenabling traps we instead
zero the parts of the SVE registers not shared with FPSIMD and leave SME
enabled, this simplifies handling SME traps. If ZA is not in use then we
reenable SME traps and fall through to normal handling of SVE.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-17-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Allocate space for storing ZA on first access to SME and use that to save
and restore ZA state when context switching. We do this by using the vector
form of the LDR and STR ZA instructions, these do not require streaming
mode and have implementation recommendations that they avoid contention
issues in shared SMCU implementations.
Since ZA is architecturally guaranteed to be zeroed when enabled we do not
need to explicitly zero ZA, either we will be restoring from a saved copy
or trapping on first use of SME so we know that ZA must be disabled.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-16-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
When in streaming mode we need to save and restore the streaming mode
SVE register state rather than the regular SVE register state. This uses
the streaming mode vector length and omits FFR but is otherwise identical,
if TIF_SVE is enabled when we are in streaming mode then streaming mode
takes precedence.
This does not handle use of streaming SVE state with KVM, ptrace or
signals. This will be updated in further patches.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-15-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
In SME the use of both streaming SVE mode and ZA are tracked through
PSTATE.SM and PSTATE.ZA, visible through the system register SVCR. In
order to context switch the floating point state for SME we need to
context switch the contents of this register as part of context
switching the floating point state.
Since changing the vector length exits streaming SVE mode and disables
ZA we also make sure we update SVCR appropriately when setting vector
length, and similarly ensure that new threads have streaming SVE mode
and ZA disabled.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-14-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The Scalable Matrix Extension introduces support for a new thread specific
data register TPIDR2 intended for use by libc. The kernel must save the
value of TPIDR2 on context switch and should ensure that all new threads
start off with a default value of 0. Add a field to the thread_struct to
store TPIDR2 and context switch it with the other thread specific data.
In case there are future extensions which also use TPIDR2 we introduce
system_supports_tpidr2() and use that rather than system_supports_sme()
for TPIDR2 handling.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-13-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
As for SVE provide a prctl() interface which allows processes to
configure their SME vector length.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-12-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
