kselftest/arm64: Limit the maximum VL we try to set via ptrace

When SVE was initially merged we chose to export the maximum VQ in the ABI
as being 512, rather more than the architecturally supported maximum of 16.
For the ptrace tests this results in us generating a lot of test cases and
hence log output which are redundant since a system couldn't possibly
support them. Instead only check values up to the current architectural
limit, plus one more so that we're covering the constraining of higher
vector lengths.

This makes no practical difference to our test coverage, speeds things up
on slower consoles and makes the output much more managable.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230111-arm64-kselftest-ptrace-max-vl-v1-1-8167f41d1ad8@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

kselftest/arm64: Add streaming SVE to SVE ptrace tests

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>

kselftest/arm64: Validate setting via FPSIMD and read via SVE regsets

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>

kselftest/arm64: Remove assumption that tasks start FPSIMD only

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>

kselftest/arm64: Fix comment for ptrace_sve_get_fpsimd_data()

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>

kselftest/arm64: Log the PIDs of the parent and child in sve-ptrace

If the test triggers a problem it may well result in a log message from
the kernel such as a WARN() or BUG(). If these include a PID it can help
with debugging to know if it was the parent or child process that triggered
the issue, since the test is just creating a new thread the process name
will be the same either way. Print the PIDs of the parent and child on
startup so users have this information to hand should it be needed.

Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220303192817.2732509-1-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

kselftest/arm64: Remove local ARRAY_SIZE() definitions

An ARRAY_SIZE() has been added to kselftest.h so remove the local versions
in some of the arm64 selftests.

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/20220124171748.2195875-1-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

kselftest/arm64: Correct logging of FPSIMD register read via ptrace

There's a cut'n'paste error in the logging for our test for reading register
state back via ptrace, correctly say that we did a read instead of a write.

Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220124175527.3260234-3-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

kselftest/arm64: Skip VL_INHERIT tests for unsupported vector types

Currently we unconditionally test the ability to set the vector length
inheritance flag via ptrace meaning that we generate false failures on
systems that don't support SVE when we attempt to set the vector length
there. Check the hwcap and mark the tests as skipped when it's not present.

Fixes: 0ba1ce1e8605 ("selftests: arm64: Add coverage of ptrace flags for SVE VL inheritance")
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220124175527.3260234-2-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

kselftest/arm64: Parameterise ptrace vector length information

SME introduces a new mode called streaming mode in which the SVE registers
have a different vector length. Since the ptrace interface for this is
based on the existing SVE interface prepare for supporting this by moving
the regset specific configuration into struct and passing that around,
allowing these tests to be reused for streaming mode. As we will also have
to verify the interoperation of the SVE and streaming SVE regsets don't
just iterate over an array.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20211210184133.320748-5-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

selftests: arm64: Add coverage of ptrace flags for SVE VL inheritance

Add a test that covers enabling and disabling of SVE vector length
inheritance via the ptrace interface.

Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20211005123537.976795-1-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

selftests: arm64: Move FPSIMD in SVE ptrace test into a function

Now that all the other tests are in functions rather than inline in the
main parent process function also move the test for accessing the FPSIMD
registers via the SVE regset out into their own function.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210913125505.52619-9-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

selftests: arm64: More comprehensively test the SVE ptrace interface

Currently the selftest for the SVE register set is not quite as thorough
as is desirable - it only validates that the value of a single Z register
is not modified by a partial write to a lower numbered Z register after
having previously been set through the FPSIMD regset.

Make this more thorough:
- Test the ability to set vector lengths and enumerate those supported in
the system.
- Validate data in all Z and P registers, plus FPSR and FPCR.
- Test reads via the FPSIMD regset after set via the SVE regset.

There's still some oversights, the main one being that due to the need to
generate a pattern in FFR and the fact that this rewrite is primarily
motivated by SME's streaming SVE which doesn't have FFR we don't currently
test FFR. Update the TODO to reflect those that occurred to me (and fix an
adjacent typo in there).

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210913125505.52619-8-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

selftests: arm64: Verify interoperation of SVE and FPSIMD register sets

After setting the FPSIMD registers via the SVE register set read them back
via the FPSIMD register set, validating that the two register sets are
interoperating and that the values we thought we set made it into the
child process.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210913125505.52619-7-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

selftests: arm64: Clarify output when verifying SVE register set

When verifying setting a Z register via ptrace we check each byte by hand,
iterating over the buffer using a pointer called p and treating each
register value written as a test. This creates output referring to "p[X]"
which is confusing since SVE also has predicate registers Pn. Tweak the
output to avoid confusion here.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210913125505.52619-6-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

selftests: arm64: Document what the SVE ptrace test is doing

Before we go modifying it further let's add some comments and output
clarifications explaining what this test is actually doing.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210913125505.52619-5-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

selftests: arm64: Remove extraneous register setting code

For some reason the SVE ptrace test code starts off by setting values in
some of the SVE vector registers in the parent process which it then never
interacts with when verifying the ptrace interfaces. This is not especially
relevant to what's being tested and somewhat confusing when reading the
code so let's remove it.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210913125505.52619-4-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

selftests: arm64: Don't log child creation as a test in SVE ptrace test

Currently we log the creation of the child process as a test but it's not
really relevant to what we're trying to test and can make the output a
little confusing so don't do that.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210913125505.52619-3-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

selftests: arm64: Use a define for the number of SVE ptrace tests to be run

Partly in preparation for future refactoring move from hard coding the
number of tests in main() to putting #define at the top of the source
instead.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210913125505.52619-2-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

kselftest: arm64: Fix exit code of sve-ptrace

We track if sve-ptrace encountered a failure in a variable but don't
actually use that value when we exit the program, do so.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210309190304.39169-1-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

selftests: arm64: Add test for the SVE ptrace interface

Add a test case that does some basic verification of the SVE ptrace
interface, forking off a child with known values in the registers and
then using ptrace to inspect and manipulate the SVE registers of the
child, including in FPSIMD mode to account for sharing between the SVE
and FPSIMD registers.

This program was written by Dave Martin and modified for kselftest by
me.

Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Dave Martin <Dave.Martin@arm.com>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20200819114837.51466-3-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>