kselftest/arm64: Use the tools/include compiler.h rather than our own

The BTI test program started life as standalone programs outside the
kselftest suite so provided it's own compiler.h. Now that we have updated
the tools/include compiler.h to have all the definitions that we are using
and the arm64 selftsets pull in tools/includes let's drop our custom
version.

__unreachable() is named unreachable() there requiring an update in the
code.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230728-arm64-signal-memcpy-fix-v4-6-0c1290db5d46@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

kselftest/arm64: Run BTI selftests on systems without BTI

The BTI selftests are built both with and without BTI support, validating
both the generation of BTI signals as expected for binaries without BTI
support. Both versions of the binary currently skip all their tests when
the system does not support BTI, however this is excessive since we do have
a defined ABI for how the programs should function in this case (especially
for the non-BTI binary). Update the test program to run all the tests
unconditionally, adding a runtime adjustment of the expected results on
systems that don't support BTI where we currently handle the build time
case.

The tests all use HINT space instructions, BTI itself is a HINT as is
are the PAC instructions that function as landing pads, so nothing in the
tests depends on support for BTI in the kernel or hardware.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230110-arm64-bti-selftest-skip-v1-2-143ecdc84567@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

kselftest/arm64: Fix test numbering when skipping tests

Currently when skipping tests in the BTI testsuite we assign the same
number to every test since we forget to increment the current test number
as we skip, causing warnings about not running the expected test count and
potentially otherwise confusing result parsers. Fix this by adding an
appropriate increment.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230110-arm64-bti-selftest-skip-v1-1-143ecdc84567@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

kselftest/arm64: Add missing stddef.h include to BTI tests

Explicitly include stddef.h when building the BTI tests so that we have
a definition of NULL, with at least some toolchains this is not done
implicitly by anything else:

test.c: In function ‘start’:
test.c:214:25: error: ‘NULL’ undeclared (first use in this function)
214 | sigaction(SIGILL, &sa, NULL);
| ^~~~
test.c:20:1: note: ‘NULL’ is defined in header ‘<stddef.h>’; did you forget to ‘#include <stddef.h>’?

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210507162542.23149-1-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

kselftest: arm64: Add BTI tests

Add some tests that verify that BTI functions correctly for static binaries
built with and without BTI support, verifying that SIGILL is generated when
expected and is not generated in other situations.

Since BTI support is still being rolled out in distributions these tests
are built entirely free standing, no libc support is used at all so none
of the standard helper functions for kselftest can be used and we open
code everything. This also means we aren't testing the kernel support for
the dynamic linker, though the test program can be readily adapted for
that once it becomes something that we can reliably build and run.

These tests were originally written by Dave Martin, I've adapted them for
kselftest, mainly around the build system and the output format.

Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: Dave Martin <Dave.Martin@arm.com>
Link: https://lore.kernel.org/r/20210309193731.57247-1-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>