kernel/linux.git/tools/testing/selftests/x86, branch v4.6.4

selftests/x86: Add an iopl test

2016-03-17T08:49:26+00:00

This exercises two cases that are known to be buggy on Xen PV right now. Signed-off-by: Andy Lutomirski Cc: Andrew Cooper Cc: Andy Lutomirski Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Brian Gerst Cc: David Vrabel Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Jan Beulich Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/61afe904c95c92abb29cd075b51e10e7feb0f774.1458162709.git.luto@kernel.org Signed-off-by: Ingo Molnar

selftests/x86: In syscall_nt, test NT|TF as well

2016-03-10T08:48:12+00:00

Setting TF prevents fastpath returns in most cases, which causes the test to fail on 32-bit kernels because 32-bit kernels do not, in fact, handle NT correctly on SYSENTER entries. The next patch will fix 32-bit kernels. Signed-off-by: Andy Lutomirski Cc: Andrew Cooper Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/bd4bb48af6b10c0dc84aec6dbcf487ed25683495.1457578375.git.luto@kernel.org Signed-off-by: Ingo Molnar

selftests/x86: Add a test for syscall restart under ptrace

2016-02-17T08:51:06+00:00

This catches a regression from the compat syscall rework. The 32-bit variant of this test currently fails. The issue is that, for a 32-bit tracer and a 32-bit tracee, GETREGS+SETREGS with no changes should be a no-op. It currently isn't a no-op if RAX indicates signal restart, because the high bits get cleared and the kernel loses track of the restart state. Reported-by: Robert O'Callahan Signed-off-by: Andy Lutomirski Cc: Al Viro Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Shuah Khan Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/c4040b40b5b4a37ed31375a69b683f753ec6788a.1455142412.git.luto@kernel.org Signed-off-by: Ingo Molnar

selftests/x86: Fix some error messages in ptrace_syscall

2016-02-17T08:51:06+00:00

I had some obvious typos. Signed-off-by: Andy Lutomirski Cc: Al Viro Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Robert O'Callahan Cc: Shuah Khan Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/e5e6772d4802986cf7df702e646fa24ac14f2204.1455142412.git.luto@kernel.org Signed-off-by: Ingo Molnar

selftests/x86: Add tests for UC_SIGCONTEXT_SS and UC_STRICT_RESTORE_SS

2016-02-17T07:32:12+00:00

This tests the two ABI-preserving cases that DOSEMU cares about, and it also explicitly tests the new UC_SIGCONTEXT_SS and UC_STRICT_RESTORE_SS flags. Signed-off-by: Andy Lutomirski Acked-by: Borislav Petkov Cc: Al Viro Cc: Andy Lutomirski Cc: Brian Gerst Cc: Cyrill Gorcunov Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Pavel Emelyanov Cc: Peter Zijlstra Cc: Shuah Khan Cc: Stas Sergeev Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/f3d08f98541d0bd3030ceb35e05e21f59e30232c.1455664054.git.luto@kernel.org Signed-off-by: Ingo Molnar

x86/signal/64: Re-add support for SS in the 64-bit signal context

2016-02-17T07:32:11+00:00

This is a second attempt to make the improvements from c6f2062935c8 ("x86/signal/64: Fix SS handling for signals delivered to 64-bit programs"), which was reverted by 51adbfbba5c6 ("x86/signal/64: Add support for SS in the 64-bit signal context"). This adds two new uc_flags flags. UC_SIGCONTEXT_SS will be set for all 64-bit signals (including x32). It indicates that the saved SS field is valid and that the kernel supports the new behavior. The goal is to fix a problems with signal handling in 64-bit tasks: SS wasn't saved in the 64-bit signal context, making it awkward to determine what SS was at the time of signal delivery and making it impossible to return to a non-flat SS (as calling sigreturn clobbers SS). This also made it extremely difficult for 64-bit tasks to return to fully-defined 16-bit contexts, because only the kernel can easily do espfix64, but sigreturn was unable to set a non-flag SS:ESP. (DOSEMU has a monstrous hack to partially work around this limitation.) If we could go back in time, the correct fix would be to make 64-bit signals work just like 32-bit signals with respect to SS: save it in signal context, reset it when delivering a signal, and restore it in sigreturn. Unfortunately, doing that (as I tried originally) breaks DOSEMU: DOSEMU wouldn't reset the signal context's SS when clearing the LDT and changing the saved CS to 64-bit mode, since it predates the SS context field existing in the first place. This patch is a bit more complicated, and it tries to balance a bunch of goals. It makes most cases of changing ucontext->ss during signal handling work as expected. I do this by special-casing the interesting case. On sigreturn, ucontext->ss will be honored by default, unless the ucontext was created from scratch by an old program and had a 64-bit CS (unfortunately, CRIU can do this) or was the result of changing a 32-bit signal context to 64-bit without resetting SS (as DOSEMU does). For the benefit of new 64-bit software that uses segmentation (new versions of DOSEMU might), the new behavior can be detected with a new ucontext flag UC_SIGCONTEXT_SS. To avoid compilation issues, __pad0 is left as an alias for ss in ucontext. The nitty-gritty details are documented in the header file. This patch also re-enables the sigreturn_64 and ldt_gdt_64 selftests, as the kernel change allows both of them to pass. Tested-by: Stas Sergeev Signed-off-by: Andy Lutomirski Acked-by: Borislav Petkov Cc: Al Viro Cc: Andy Lutomirski Cc: Brian Gerst Cc: Cyrill Gorcunov Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Pavel Emelyanov Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/749149cbfc3e75cd7fcdad69a854b399d792cc6f.1455664054.git.luto@kernel.org [ Small readability edit. ] Signed-off-by: Ingo Molnar

selftests/x86: Add check_initial_reg_state()

2016-01-29T08:46:37+00:00

This checks that ELF binaries are started with an appropriately blank register state. ( There's currently a nasty special case in the entry asm to arrange for this. I'm planning on removing the special case, and this will help make sure I don't break it. ) Signed-off-by: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: Frederic Weisbecker Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/ef54f8d066b30a3eb36bbf26300eebb242185700.1454022279.git.luto@kernel.org Signed-off-by: Ingo Molnar

selftests/x86: Extend Makefile to allow 64-bit-only tests

2016-01-29T08:46:36+00:00

Previously the Makefile supported 32-bit-only tests and tests that were 32-bit and 64-bit. This adds the support for tests that are only built as 64-bit binaries. There aren't any yet, but there might be a few some day. Signed-off-by: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: Frederic Weisbecker Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Shuah Khan Cc: Thomas Gleixner Cc: linux-api@vger.kernel.org Link: http://lkml.kernel.org/r/99789bfe65706e6df32cc7e13f656e8c9fa92031.1454022279.git.luto@kernel.org Signed-off-by: Ingo Molnar

selftests/x86: Test __kernel_sigreturn and __kernel_rt_sigreturn

2016-01-13T09:34:40+00:00

The vdso-based sigreturn mechanism is fragile and isn't used by modern glibc so, if we break it, we'll only notice when someone tests an unusual libc. Add an explicit selftest. [ I wrote this while debugging a Bionic breakage -- my first guess was that I had somehow messed up sigreturn. I've caused problems in that code before, and it's really easy to fail to notice it because there's nothing on a modern distro that needs vdso-based sigreturn. ] Signed-off-by: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Shuah Khan Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/32946d714156879cd8e5d8eab044cd07557ed558.1452628504.git.luto@kernel.org Signed-off-by: Ingo Molnar

selftests/x86: Disable the ldt_gdt_64 test for now

2016-01-12T10:09:26+00:00

ldt_gdt.c relies on cross-cpu invalidation of SS to do one of its tests. On 32-bit builds, this works fine, but on 64-bit builds, it only works if the kernel has proper SS sigcontext handling for 64-bit user programs. Since the SS fixes are currently reverted, restrict the test case to 32 bits for now. In principle, I could change the test to use a different segment register, but it would be messy: CS can't point to the LDT for 64-bit code, and the other registers don't result in immediate faults because they aren't reloaded on kernel -> user transitions. When we fix sigcontext (in 4.6?), we can revert this. Signed-off-by: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Shuah Khan Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/231591d9122d282402d8f53175134f8db5b3bc73.1452561752.git.luto@kernel.org Signed-off-by: Ingo Molnar