Commit Graph

4 Commits

Author SHA1 Message Date
Mark Brown
9f93c2e0cd kselftest/arm64: Explicitly build no BTI tests with BTI disabled
In case a distribution enables branch protection by default do as we do for
the main kernel and explicitly disable branch protection when building the
test case for having BTI disabled to ensure it doesn't get turned on by the
toolchain defaults.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220516182213.727589-1-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2022-05-16 19:43:40 +01:00
Andre Przywara
d7a49291d7 kselftest/arm64: bti: force static linking
The "bti" selftests are built with -nostdlib, which apparently
automatically creates a statically linked binary, which is what we want
and need for BTI (to avoid interactions with the dynamic linker).

However this is not true when building a PIE binary, which some
toolchains (Ubuntu) configure as the default.
When compiling btitest with such a toolchain, it will create a
dynamically linked binary, which will probably fail some tests, as the
dynamic linker might not support BTI:
===================
TAP version 13
1..18
not ok 1 nohint_func/call_using_br_x0
not ok 2 nohint_func/call_using_br_x16
not ok 3 nohint_func/call_using_blr
....
===================

To make sure we create static binaries, add an explicit -static on the
linker command line. This forces static linking even if the toolchain
defaults to PIE builds, and fixes btitest runs on BTI enabled machines.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Fixes: 314bcbf09f ("kselftest: arm64: Add BTI tests")
Link: https://lore.kernel.org/r/20220511172129.2078337-1-andre.przywara@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2022-05-16 19:03:14 +01:00
Mark Brown
a1bed090fc 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>
2021-05-10 10:19:01 +01:00
Mark Brown
314bcbf09f 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>
2021-03-24 15:43:20 +00:00