kselftest/arm64: Enable build of PAC tests with LLVM=1

Currently we don't build the PAC selftests when building with LLVM=1 since
we attempt to test for PAC support in the toolchain before we've set

kselftest/arm64: Enable build of PAC tests with LLVM=1

Currently we don't build the PAC selftests when building with LLVM=1 since
we attempt to test for PAC support in the toolchain before we've set up the
build system to point at LLVM in lib.mk, which has to be one of the last
things in the Makefile.

Since all versions of LLVM supported for use with the kernel have PAC
support we can just sidestep the issue by just assuming PAC is there when
doing a LLVM=1 build.

Signed-off-by: Mark Brown <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Catalin Marinas <[email protected]>

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kselftests/arm64: add PAuth test for whether exec() changes keys

Kernel documentation states that it will change PAuth keys on exec() calls.

Verify that all keys are correctly switched to new ones.

kselftests/arm64: add PAuth test for whether exec() changes keys

Kernel documentation states that it will change PAuth keys on exec() calls.

Verify that all keys are correctly switched to new ones.

Signed-off-by: Boyan Karatotev <[email protected]>
Reviewed-by: Vincenzo Frascino <[email protected]>
Reviewed-by: Amit Daniel Kachhap <[email protected]>
Acked-by: Shuah Khan <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Will Deacon <[email protected]>

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kselftests/arm64: add nop checks for PAuth tests

PAuth adds sign/verify controls to enable and disable groups of
instructions in hardware for compatibility with libraries that do not
implement PAuth

kselftests/arm64: add nop checks for PAuth tests

PAuth adds sign/verify controls to enable and disable groups of
instructions in hardware for compatibility with libraries that do not
implement PAuth. The kernel always enables them if it detects PAuth.

Add a test that checks that each group of instructions is enabled, if the
kernel reports PAuth as detected.

Note: For groups, for the purpose of this patch, we intend instructions
that use a certain key.

Signed-off-by: Boyan Karatotev <[email protected]>
Reviewed-by: Vincenzo Frascino <[email protected]>
Reviewed-by: Amit Daniel Kachhap <[email protected]>
Acked-by: Shuah Khan <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Will Deacon <[email protected]>

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kselftests/arm64: add a basic Pointer Authentication test

PAuth signs and verifies return addresses on the stack. It does so by
inserting a Pointer Authentication code (PAC) into some of the unused

kselftests/arm64: add a basic Pointer Authentication test

PAuth signs and verifies return addresses on the stack. It does so by
inserting a Pointer Authentication code (PAC) into some of the unused top
bits of an address. This is achieved by adding paciasp/autiasp instructions
at the beginning and end of a function.

This feature is partially backwards compatible with earlier versions of the
ARM architecture. To coerce the compiler into emitting fully backwards
compatible code the main file is compiled to target an earlier ARM version.
This allows the tests to check for the feature and print meaningful error
messages instead of crashing.

Add a test to verify that corrupting the return address results in a
SIGSEGV on return.

Signed-off-by: Boyan Karatotev <[email protected]>
Reviewed-by: Vincenzo Frascino <[email protected]>
Reviewed-by: Amit Daniel Kachhap <[email protected]>
Acked-by: Shuah Khan <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Will Deacon <[email protected]>

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