kernel/tools/testing/selftests/x86/single_step_syscall.c, branch linux-4.16.y

selftests/x86: Do not rely on "int $0x80" in single_step_syscall.c

2018-02-15T00:15:48Z

On 64-bit builds, we should not rely on "int $0x80" working (it only does if CONFIG_IA32_EMULATION=y is enabled). To keep the "Set TF and check int80" test running on 64-bit installs with CONFIG_IA32_EMULATION=y enabled, build this test only if we can also build 32-bit binaries (which should be a good approximation for that). Signed-off-by: Dominik Brodowski Cc: Andy Lutomirski Cc: Dmitry Safonov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kselftest@vger.kernel.org Cc: shuah@kernel.org Link: http://lkml.kernel.org/r/20180211111013.16888-5-linux@dominikbrodowski.net Signed-off-by: Ingo Molnar

x86/selftests: Add clobbers for int80 on x86_64

2017-03-01T09:24:56Z

Kernel erases R8..R11 registers prior returning to userspace from int80: https://lkml.org/lkml/2009/10/1/164 GCC can reuse these registers and doesn't expect them to change during syscall invocation. I met this kind of bug in CRIU once GCC 6.1 and CLANG stored local variables in those registers and the kernel zerofied them during syscall: https://github.com/xemul/criu/commit/990d33f1a1cdd17bca6c2eb059ab3be2564f7fa2 By that reason I suggest to add those registers to clobbers in selftests. Also, as noted by Andy - removed unneeded clobber for flags in INT $0x80 inline asm. Signed-off-by: Dmitry Safonov Acked-by: Andy Lutomirski Cc: 0x7f454c46@gmail.com Cc: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Shuah Khan Cc: Thomas Gleixner Cc: linux-kselftest@vger.kernel.org Link: http://lkml.kernel.org/r/20170213101336.20486-1-dsafonov@virtuozzo.com Signed-off-by: Ingo Molnar

x86, selftests: Add single_step_syscall test

2015-04-16T10:41:49Z

This is a very simple test that makes system calls with TF set. This test currently fails when running the 32-bit build on a 64-bit kernel on an Intel CPU. This bug will be fixed by the next commit. Signed-off-by: Andy Lutomirski Cc: Borislav Petkov Cc: Denys Vlasenko Cc: Oleg Nesterov Cc: Shuah Khan Link: http://lkml.kernel.org/r/20e68021155f6ab5c60590dcad81d37c68ea2c4f.1429139075.git.luto@kernel.org Signed-off-by: Ingo Molnar