linux/tools/testing/selftests/rseq, branch v5.2

Merge tag 'linux-kselftest-5.2-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

2019-05-17T01:57:58Z

Pull more kselftest updates from Shuah Khan: - kselftest framework bpf build/test workflow regression fix - Fix to kselftest install to use default install path - Fix to kselftest KBUILD_OUTPUT builds to not clutter main KBUILD_OUTPUT directory with selftest objects - .gitignore fixes (Kelsey Skunberg) - rseq selftests updates (Mathieu Desnoyers and Martin Schwidefsky) They change the per-architecture pre-abort signatures to ensure those are valid trap instructions. The way exit points are presented to debuggers is enhanced, ensuring all exit points are present, so debuggers don't have to disassemble rseq critical section to properly skip over them. Discussions with the glibc community is reaching a consensus of exposing a __rseq_handled symbol from glibc to coexist with rseq early adopters. Update the rseq selftest code to expose and use this symbol. Support for compiling asm goto with clang is added with the "-no-integrated-as" compiler switch, similarly to the top level kernel Makefile. - kselftest Makefile test run output refactoring and making test output TAP13 compliant from Kees Cook: This re-factors the selftest Makefiles to extract the test running logic to be reused between "run_tests" and "emit_tests", while also fixing up the test output to be TAP version 13 compliant: - added "plan" line - fixed result line syntax - moved all test output to be "# "-prefixed as TAP "diagnostic" lines The prefixing code includes a fallback mode for limited execution environments. Additionally, the plan lines are fixed for all callers of kselftest.h. * tag 'linux-kselftest-5.2-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (25 commits) selftests: avoid KBUILD_OUTPUT dir cluttering with selftest objects selftests: drivers: Create .gitignore to include /dma-buf/udmabuf selftests: pidfd: Create .gitignore to include pidfd_test selftests: fix bpf build/test workflow regression when KBUILD_OUTPUT is set selftests: fix install target to use default install path rseq/selftests: add -no-integrated-as for clang rseq/selftests: mips: use break instruction for RSEQ_SIG rseq/selftests: powerpc code signature: generate valid instructions rseq/selftests: aarch64 code signature: handle big-endian environment rseq/selftests: arm: use udf instruction for RSEQ_SIG rseq/selftests: s390: use trap4 for RSEQ_SIG rseq/selftests: x86: use ud1 instruction as RSEQ_SIG opcode rseq/selftests: s390: use jg instruction for jumps outside of the asm rseq/selftests: Use __rseq_handled symbol to coexist with glibc rseq/selftests: Introduce __rseq_cs_ptr_array, rename __rseq_table to __rseq_cs rseq/selftests: Add __rseq_exit_point_array section for debuggers rseq/selftests: x86: Work-around bogus gcc-8 optimisation selftests: Add test plan API to kselftest.h and adjust callers selftests: Remove KSFT_TAP_LEVEL selftests: Move test output to diagnostic lines ...

rseq/selftests: add -no-integrated-as for clang

2019-05-07T21:33:17Z

Ongoing work for asm goto support from clang requires the -no-integrated-as compiler flag. This compiler flag is present in the toplevel kernel Makefile, but is not replicated for selftests. Add it specifically for the rseq selftest which requires asm goto. Link: https://reviews.llvm.org/D56571 Signed-off-by: Mathieu Desnoyers CC: Nick Desaulniers CC: Thomas Gleixner CC: Joel Fernandes CC: Peter Zijlstra CC: Catalin Marinas CC: Dave Watson CC: Will Deacon CC: Shuah Khan CC: Andi Kleen CC: linux-kselftest@vger.kernel.org CC: "H . Peter Anvin" CC: Chris Lameter CC: Russell King CC: Michael Kerrisk CC: "Paul E . McKenney" CC: Paul Turner CC: Boqun Feng CC: Josh Triplett CC: Steven Rostedt CC: Ben Maurer CC: linux-api@vger.kernel.org CC: Andy Lutomirski CC: Andrew Morton CC: Linus Torvalds Reviewed-by: Nick Desaulniers Signed-off-by: Shuah Khan

rseq/selftests: mips: use break instruction for RSEQ_SIG

2019-05-07T21:33:09Z

Use break as guard instruction for the restartable sequence abort handler. Previously, the chosen signature was simply data, based on the assumption that it could always sit in a literal pool. However, some compilation environments favor disabling literal pool. Therefore, ensure the signature is a valid uncommon trap instruction. Suggested-by: Paul Burton Signed-off-by: Mathieu Desnoyers CC: Paul Burton CC: James Hogan Cc: Ralf Baechle Cc: Mathieu Desnoyers Cc: Peter Zijlstra Cc: Paul E. McKenney Cc: Boqun Feng Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Shuah Khan

rseq/selftests: powerpc code signature: generate valid instructions

2019-05-07T21:33:00Z

Use "twui" as the guard instruction for the restartable sequence abort handler. Signed-off-by: Mathieu Desnoyers CC: Benjamin Herrenschmidt CC: Paul Mackerras CC: Michael Ellerman CC: Boqun Feng CC: Peter Zijlstra CC: "Paul E. McKenney" CC: Alan Modra CC: linuxppc-dev@lists.ozlabs.org Signed-off-by: Shuah Khan

rseq/selftests: aarch64 code signature: handle big-endian environment

2019-05-07T21:32:51Z

Handle compiling with -mbig-endian on aarch64, which generates binaries with mixed code vs data endianness (little endian code, big endian data). Else mismatch between code endianness for the generated signatures and data endianness for the RSEQ_SIG parameter passed to the rseq registration will trigger application segmentation faults when the kernel try to abort rseq critical sections. Signed-off-by: Mathieu Desnoyers Acked-by: Will Deacon CC: Peter Zijlstra CC: Thomas Gleixner CC: Joel Fernandes CC: Catalin Marinas CC: Dave Watson CC: Will Deacon CC: Shuah Khan CC: Andi Kleen CC: linux-kselftest@vger.kernel.org CC: "H . Peter Anvin" CC: Chris Lameter CC: Russell King CC: Michael Kerrisk CC: "Paul E . McKenney" CC: Paul Turner CC: Boqun Feng CC: Josh Triplett CC: Steven Rostedt CC: Ben Maurer CC: linux-api@vger.kernel.org CC: Andy Lutomirski CC: Andrew Morton CC: Linus Torvalds Signed-off-by: Shuah Khan

rseq/selftests: arm: use udf instruction for RSEQ_SIG

2019-05-07T21:32:36Z

Use udf as the guard instruction for the restartable sequence abort handler. Previously, the chosen signature was not a valid instruction, based on the assumption that it could always sit in a literal pool. However, there are compilation environments in which literal pools are not available, for instance execute-only code. Therefore, we need to choose a signature value that is also a valid instruction. Handle compiling with -mbig-endian on ARMv6+, which generates binaries with mixed code vs data endianness (little endian code, big endian data). Else mismatch between code endianness for the generated signatures and data endianness for the RSEQ_SIG parameter passed to the rseq registration will trigger application segmentation faults when the kernel try to abort rseq critical sections. Prior to ARMv6, -mbig-endian generates big-endian code and data, so endianness should not be reversed in that case. Signed-off-by: Mathieu Desnoyers CC: Peter Zijlstra CC: Thomas Gleixner CC: Joel Fernandes CC: Catalin Marinas CC: Dave Watson CC: Will Deacon CC: Shuah Khan CC: Andi Kleen CC: linux-kselftest@vger.kernel.org CC: "H . Peter Anvin" CC: Chris Lameter CC: Russell King CC: Michael Kerrisk CC: "Paul E . McKenney" CC: Paul Turner CC: Boqun Feng CC: Josh Triplett CC: Steven Rostedt CC: Ben Maurer CC: linux-api@vger.kernel.org CC: Andy Lutomirski CC: Andrew Morton CC: Linus Torvalds Signed-off-by: Shuah Khan

rseq/selftests: s390: use trap4 for RSEQ_SIG

2019-05-07T21:32:14Z

Use trap4 as the guard instruction for the restartable sequence abort handler. Signed-off-by: Martin Schwidefsky Signed-off-by: Mathieu Desnoyers Signed-off-by: Shuah Khan

rseq/selftests: x86: use ud1 instruction as RSEQ_SIG opcode

2019-05-07T21:32:05Z

Use ud1 as the guard instruction for the restartable sequence abort handler. Its benefit compared to nopl is to trap execution if the program ends up trying to execute it by mistake, which makes debugging easier. The 4-byte signature per se is unchanged (it is the instruction operand). Only the opcode is changed from nopl to ud1. Signed-off-by: Mathieu Desnoyers Suggested-by: Peter Zijlstra CC: Peter Zijlstra CC: Thomas Gleixner CC: Joel Fernandes CC: Catalin Marinas CC: Dave Watson CC: Will Deacon CC: Shuah Khan CC: Andi Kleen CC: linux-kselftest@vger.kernel.org CC: "H . Peter Anvin" CC: Chris Lameter CC: Russell King CC: Michael Kerrisk CC: "Paul E . McKenney" CC: Paul Turner CC: Boqun Feng CC: Josh Triplett CC: Steven Rostedt CC: Ben Maurer CC: linux-api@vger.kernel.org CC: Andy Lutomirski CC: Andrew Morton CC: Linus Torvalds Signed-off-by: Shuah Khan

rseq/selftests: s390: use jg instruction for jumps outside of the asm

2019-05-07T21:31:55Z

The branch target range of the "j" instruction is 64K, which is not enough for the general case. Suggested-by: Martin Schwidefsky Signed-off-by: Mathieu Desnoyers CC: Thomas Gleixner CC: Joel Fernandes CC: Peter Zijlstra CC: Catalin Marinas CC: Dave Watson CC: Will Deacon CC: Shuah Khan CC: Andi Kleen CC: linux-kselftest@vger.kernel.org CC: "H . Peter Anvin" CC: Chris Lameter CC: Russell King CC: Michael Kerrisk CC: "Paul E . McKenney" CC: Paul Turner CC: Boqun Feng CC: Josh Triplett CC: Steven Rostedt CC: Ben Maurer CC: linux-api@vger.kernel.org CC: Andy Lutomirski CC: Andrew Morton CC: Linus Torvalds Signed-off-by: Shuah Khan

rseq/selftests: Use __rseq_handled symbol to coexist with glibc

2019-05-07T21:31:46Z

In order to integrate rseq into user-space applications, expose a __rseq_handled symbol so many rseq users can be linked into the same application (e.g. librseq and glibc). The __rseq_refcount TLS variable is static to the librseq library. It ensures that rseq syscall registration/unregistration happens only for the most early/late caller to rseq_{,un}register_current_thread for each thread, thus ensuring that rseq is registered across the lifetime of all rseq users for a given thread. Signed-off-by: Mathieu Desnoyers CC: Shuah Khan CC: Carlos O'Donell CC: Florian Weimer CC: Joseph Myers CC: Szabolcs Nagy CC: Thomas Gleixner CC: Ben Maurer CC: Peter Zijlstra CC: "Paul E. McKenney" CC: Boqun Feng CC: Will Deacon CC: Dave Watson CC: Paul Turner CC: linux-api@vger.kernel.org Signed-off-by: Shuah Khan