kernel/tools/testing/selftests/x86/amx.c, branch linux-rolling-stable

selftests/x86/xstate: Consolidate test invocations into a single entry

2025-02-26T12:05:29Z

Currently, each of the three xstate tests runs as a separate invocation, requiring the xstate number to be passed and state information to be reconstructed repeatedly. This approach arose from their individual and isolated development, but now it makes sense to unify them. Introduce a wrapper function that first verifies feature availability from the kernel and constructs the necessary state information once. The wrapper then sequentially invokes all tests to ensure consistent execution. Update the AMX test to use this unified invocation. Signed-off-by: Chang S. Bae Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20250226010731.2456-8-chang.seok.bae@intel.com

selftests/x86/xstate: Introduce signal ABI test

2025-02-26T12:05:29Z

With the refactored test cases, another xstate exposure to userspace is through signal delivery. While amx.c includes signal-related scenarios, its primary focus is on xstate permission management, which is largely specific to dynamic states. The remaining gap is testing xstate preservation and restoration across signal delivery. The kernel defines an ABI for presenting xstate in the signal frame, closely resembling the hardware XSAVE format, where xstate modification is also possible. Introduce a new test case to verify xstate preservation across signal delivery and return, that is ensuring ABI compatibility by: - Loading xstate before raising a signal. - Verifying correct exposure in the signal frame - Modifying xstate in the signal frame before returning. - Checking the state restoration upon signal return. Integrate this test into the AMX test suite as an initial usage site. Expected output: $ amx_64 ... [RUN] AMX Tile data: load xstate and raise SIGUSR1 [OK] 'magic1' is valid [OK] 'xfeatures' in SW reserved area is valid [OK] 'xfeatures' in XSAVE header is valid [OK] xstate delivery was successful [OK] 'magic2' is valid [RUN] AMX Tile data: load new xstate from sighandler and check it after sigreturn [OK] xstate was restored correctly Signed-off-by: Chang S. Bae Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20250226010731.2456-7-chang.seok.bae@intel.com

selftests/x86/xstate: Refactor ptrace ABI test

2025-02-26T12:05:29Z

Following the refactoring of the context switching test, the ptrace test is another component reusable for other xstate features. As part of this restructuring, add a missing check to validate the user_xstateregs->xstate_fx_sw field in the ABI. Also, replace err() and fatal_error() with ksft_exit_fail_msg() for consistency in error handling. Expected output: $ amx_64 ... [RUN] AMX Tile data: inject xstate via ptrace(). [OK] 'xfeatures' in SW reserved area was correctly written [OK] xstate was correctly updated. Signed-off-by: Chang S. Bae Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20250226010731.2456-6-chang.seok.bae@intel.com

selftests/x86/xstate: Refactor context switching test

2025-02-26T12:05:29Z

The existing context switching and ptrace tests in amx.c are not specific to dynamic states, making them reusable for general xstate testing. As a first step, move the context switching test to xstate.c. Refactor the test code to allow specifying which xstate component being tested. To decouple the test from dynamic states, remove the permission request code. In fact, The permission request inside the test wrapper was redundant. Additionally, replace fatal_error() with ksft_exit_fail_msg() for consistency in error handling. Expected output: $ amx_64 ... [RUN] AMX Tile data: check context switches, 10 iterations, 5 threads. [OK] No incorrect case was found. Signed-off-by: Chang S. Bae Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20250226010731.2456-5-chang.seok.bae@intel.com

selftests/x86/xstate: Enumerate and name xstate components

2025-02-26T12:05:28Z

After moving essential helpers from amx.c, the code remains neutral regarding which xstate components it handles. However, explicitly listing known components helps users identify which features are ready for testing. Enumerate xstate components to facilitate identification. Extend struct xstate_info to include a name field, providing a human-readable identifier. Signed-off-by: Chang S. Bae Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20250226010731.2456-4-chang.seok.bae@intel.com

selftests/x86/xstate: Refactor XSAVE helpers for general use

2025-02-26T12:05:28Z

The AMX test introduced several XSAVE-related helper functions, but so far, it has been the only user of them. These helpers can be generalized for broader test of multiple xstate features. Move most XSAVE-related code into xsave.h, making it shareable. The restructuring includes: * Establishing low-level XSAVE helpers for saving and restoring register states, as well as handling XSAVE buffers. * Generalizing state data manipuldations: set_rand_data() * Introducing a generic feature query helper: get_xstate_info() While doing so, remove unused defines in amx.c. Signed-off-by: Chang S. Bae Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20250226010731.2456-3-chang.seok.bae@intel.com

selftests/x86: Consolidate redundant signal helper functions

2025-02-26T12:05:28Z

The x86 selftests frequently register and clean up signal handlers, but the sethandler() and clearhandler() functions have been redundantly copied across multiple .c files. Move these functions to helpers.h to enable reuse across tests, eliminating around 250 lines of duplicate code. Converge the error handling by using ksft_exit_fail_msg(), which is functionally equivalent with err() within the selftest framework. This change is a prerequisite for the upcoming xstate selftest, which requires signal handling for registering and cleaning up handlers. Signed-off-by: Chang S. Bae Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20250226010731.2456-2-chang.seok.bae@intel.com

selftests/x86: remove (or use) unused variables and functions

2024-07-11T17:23:55Z

When building with clang, via: make LLVM=1 -C tools/testing/selftests ...quite a few functions are variables are generating "unused" warnings. Fix the warnings by deleting the unused items. One item, the "nerrs" variable in vsdo_restorer.c's main(), is unused but probably wants to be returned from main(), as a non-zero result. That result is also unused right now, so another option would be to delete it entirely, but this way, main() also gets fixed. It was missing a return value. Acked-by: Muhammad Usama Anjum Signed-off-by: John Hubbard Signed-off-by: Shuah Khan

x86/selftests: Skip the tests if prerequisites aren't fulfilled

2024-03-29T07:33:40Z

Skip instead of failing when prerequisite conditions aren't fulfilled, such as invalid xstate values etc. Make the tests show as 'SKIP' when run: make -C tools/testing/selftests/ TARGETS=x86 run_tests ... # timeout set to 45 # selftests: x86: amx_64 # # xstate cpuid: invalid tile data size/offset: 0/0 ok 42 selftests: x86: amx_64 # SKIP # timeout set to 45 # selftests: x86: lam_64 # # Unsupported LAM feature! ok 43 selftests: x86: lam_64 # SKIP ... In the AMX test, Move away from check_cpuid_xsave() and start using arch_prctl() to find out if AMX support is present or not. In the kernels where AMX isn't present, arch_prctl() returns -EINVAL, hence it is backward compatible. Signed-off-by: Muhammad Usama Anjum Signed-off-by: Ingo Molnar Reviewed-by: Chang S. Bae Reviewed-by: Binbin Wu Acked-by: Kirill A. Shutemov Link: https://lore.kernel.org/r/20240327111720.3509180-1-usama.anjum@collabora.com

selftests/x86/amx: Add a ptrace test

2023-03-22T18:00:49Z

Include a test case to validate the XTILEDATA injection to the target. Also, it ensures the kernel's ability to copy states between different XSAVE formats. Refactor the memcmp() code to be usable for the state validation. Signed-off-by: Chang S. Bae Signed-off-by: Dave Hansen Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/20230227210504.18520-3-chang.seok.bae%40intel.com