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In the MTE tests there are several places where we use chains of if
statements to open code what could be written as switch statements, move
over to switch statements to make the idiom clearer.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220510164520.768783-6-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Void pointers may be freely used with other pointer types in C, any casts
between void * and other pointer types serve no purpose other than to
mask potential warnings. Drop such casts from check_tags_inclusion to
help with future review of the code.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220510164520.768783-5-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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The MTE check_tags_inclusion test uses the mte_switch_mode() helper but
ignores the return values it generates meaning we might not be testing
the things we're trying to test, fail the test if it reports an error.
The helper will log any errors it returns.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220510164520.768783-4-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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mte_switch_mode() currently rejects attempts to set a zero tag however
there are tests such as check_tags_inclusion which attempt to cover cases
with zero tags using mte_switch_mode(). Since it is not clear why we are
rejecting zero tags change the test to accept them.
The issue has not previously been as apparent as it should be since the
return value of mte_switch_mode() was not always checked in the callers
and the tests weren't otherwise failing.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220510164520.768783-3-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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When we detect a problem in verify_mte_pointer_validity() while checking
tags we don't log what the problem was which makes debugging harder. Add
some diagnostics.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220510164520.768783-2-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Currently the arm64 kselftests attempt to locate the ABI headers using
custom logic which doesn't work correctly in the case of out of tree builds
if KBUILD_OUTPUT is not specified. Since lib.mk defines KHDR_INCLUDES with
the appropriate flags we can simply remove the custom logic and use that
instead.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220503231655.211346-1-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Currently the arm64 floating point tests don't support out of tree builds
due to two quirks of the kselftest build system. One is that when building
a program from multiple files we shouldn't separately compile the main
program to an object file as that will result in the pattern rule not
matching when adjusted for the output directory. The other is that we also
need to include $(OUTPUT) in the names of the binaries when specifying the
dependencies in order to ensure that they get picked up with O=.
Rewrite the dependencies for the executables to fix these issues. The
kselftest build system will ensure OUTPUT is always defined.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220427181954.357975-5-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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We provide a couple of object files with helpers linked into several of
the test programs, ensure they are cleaned.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220427181954.357975-4-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Some of the rules in lib.mk use a top_srcdir variable to figure out where
the top of the kselftest tree is, provide it.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220427181954.357975-3-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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The kselftest lib.mk provides a default all target which builds additional
programs from TEST_GEN_PROGS_EXTENDED, use that rather than using
TEST_PROGS_EXTENDED which is for programs that don't need to be built like
shell scripts. Leave fpsimd-stress and sve-stress there since they are
scripts.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220427181954.357975-2-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Fix the following coccicheck warnings:
tools/testing/selftests/arm64/mte/check_child_memory.c:110:25-26:
WARNING: Use ARRAY_SIZE
tools/testing/selftests/arm64/mte/check_child_memory.c:88:24-25:
WARNING: Use ARRAY_SIZE
tools/testing/selftests/arm64/mte/check_child_memory.c:90:20-21:
WARNING: Use ARRAY_SIZE
tools/testing/selftests/arm64/mte/check_child_memory.c:147:24-25:
WARNING: Use ARRAY_SIZE
`ARRAY_SIZE` macro is defined in tools/testing/selftests/kselftest.h.
Signed-off-by: Guo Zhengkui <guozhengkui@vivo.com>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220419032501.22790-1-guozhengkui@vivo.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Add a small testcase that attempts to do a clone() with ZA enabled and
verifies that it remains enabled with the same contents. We only check
one word in one horizontal vector of ZA since there's already other tests
that check for data corruption more broadly, we're just looking to make
sure that ZA is still enabled and it looks like the data got copied.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220419112247.711548-40-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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For every possible combination of SVE and SME vector length verify that for
each possible value of SVCR after a syscall we leave streaming mode and ZA
is preserved. We don't need to take account of any streaming/non streaming
SVE vector length changes in the assembler code since the store instructions
will handle the vector length for us. We log if the system supports FA64 and
only try to set FFR in streaming mode if it does.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-39-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Add some basic coverage for the ZA ptrace interface, including walking
through all the vector lengths supported in the system. Unlike SVE
doing syscalls does not discard the ZA state so when we set data in ZA
we run the child process briefly, having it add one to each byte in ZA
in order to validate that both the vector size and data are being read
and written as expected when the process runs.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-38-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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In order to allow ptrace of streaming mode SVE registers we have added a
new regset for streaming mode which in isolation offers the same ABI as
regular SVE with a different vector type. Add this to the array of regsets
we handle, together with additional tests for the interoperation of the
two regsets.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-37-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Add test cases for the SME signal handing ABI patterned off the SVE tests.
Due to the small size of the tests and the differences in ABI (especially
around needing to account for both streaming SVE and ZA) there is some code
duplication here.
We currently cover:
- Reporting of the vector length.
- Lack of support for changing vector length.
- Presence and size of register state for streaming SVE and ZA.
As with the SVE tests we do not yet have any validation of register
contents.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-36-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Add a stress test for context switching of the ZA register state based on
the similar tests Dave Martin wrote for FPSIMD and SVE registers. The test
loops indefinitely writing a data pattern to ZA then reading it back and
verifying that it's what was expected.
Unlike the other tests we manually assemble the SME instructions since at
present no released toolchain has SME support integrated.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-35-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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As part of the generic code for signal handling test cases we parse all
signal frames to make sure they have at least the basic form we expect
and that there are no unexpected frames present in the signal context.
Add coverage of the ZA signal frame to this code.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-34-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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One of the features of SME is the addition of streaming mode, in which we
have access to a set of streaming mode SVE registers at the SME vector
length. Since these are accessed using the SVE instructions let's reuse
the existing SVE stress test for testing with a compile time option for
controlling the few small differences needed:
- Enter streaming mode immediately on starting the program.
- In streaming mode FFR is removed so skip reading and writing FFR.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-33-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Provide RDVL helpers for SME and extend the main vector configuration tests
to cover SME.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-32-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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The Scalable Matrix Extension adds a new system register TPIDR2 intended to
be used by libc for its own thread specific use, add some kselftests which
exercise the ABI for it.
Since this test should with some adjustment work for TPIDR and any other
similar registers added in future add tests for it in a separate
directory rather than placing it with the other floating point tests,
nothing existing looked suitable so I created a new test directory
called "abi".
Since this feature is intended to be used by libc the test is built as
freestanding code using nolibc so we don't end up with the test program
and libc both trying to manage the register simultaneously and
distrupting each other. As a result of being written using nolibc rather
than using hwcaps to identify if SME is available in the system we check
for the default SME vector length configuration in proc, adding hwcap
support to nolibc seems like disproportionate effort and didn't feel
entirely idiomatic for what nolibc is trying to do.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-31-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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The Scalable Matrix Extenions (SME) introduces additional register state
with configurable vector lengths, similar to SVE but configured separately.
Extend vlset to support configuring this state with a --sme or -s command
line option.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-30-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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As for the kernel so that we don't have ambitious toolchain requirements
to build the tests manually encode some of the SVE instructions.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-29-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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The current tests use the prctls for various things but there's no
coverage of the edges of the interface so add some basics. This isn't
hugely useful as it is (it originally had some coverage for the
combinations with asymmetric mode but we removed the prctl() for that)
but it might be a helpful starting point for future work, for example
covering error handling.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220419103243.24774-5-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Currently we just have a big if statement with a non-specific diagnostic
checking both the mode and the tag. Since we'll need to dynamically check
for asymmetric mode support in the system and to improve debugability split
these checks out.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220419103243.24774-4-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Help people figure out problems by printing a diagnostic when we get an
unexpected asynchronous fault.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220419103243.24774-3-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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The MTE selftests have a helper evaluate_test() which translates a return
code into a call to ksft_test_result_*(). Currently this only handles pass
and fail, silently ignoring any other code. Update the helper to support
skipped tests and log any unknown return codes as an error so we get at
least some diagnostic if anything goes wrong.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220419103243.24774-2-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Currently we validate that we can set the floating point state via the SVE
regset and read the data via the FPSIMD regset but we do not valiate that
the opposite case works as expected. Add a test that covers this case,
noting that when reading via SVE regset the kernel has the option of
returning either SVE or FPSIMD data so we need to accept both formats.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220404090613.181272-4-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Currently the sve-ptrace test for setting and reading FPSIMD data assumes
that the child will start off in FPSIMD only mode and that it can use this
to read some FPSIMD mode SVE ptrace data, skipping the test if it can't.
This isn't an assumption guaranteed by the ABI and also limits how we can
use this testcase within the program. Instead skip the initial read and
just generate a FPSIMD format buffer for the write part of the test, making
the coverage more robust in the face of future kernel and test program
changes.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220404090613.181272-3-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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The comment for ptrace_sve_get_fpsimd_data() doesn't describe what the test
does at all, fix that.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220404090613.181272-2-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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As for SVE provide a sysctl which allows the default SME vector length to
be configured.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-11-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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The vector lengths used for SME are controlled through a similar set of
registers to those for SVE and enumerated using a similar algorithm with
some slight differences due to the fact that unlike SVE there are no
restrictions on which combinations of vector lengths can be supported
nor any mandatory vector lengths which must be implemented. Add a new
vector type and implement support for enumerating it.
One slightly awkward feature is that we need to read the current vector
length using a different instruction (or enter streaming mode which
would have the same issue and be higher cost). Rather than add an ops
structure we add special cases directly in the otherwise generic
vec_probe_vqs() function, this is a bit inelegant but it's the only
place where this is an issue.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-10-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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