linux-stable.git/tools/testing/selftests/x86, branch linux-4.7.y

selftests/x86/ldt_gdt: Test set_thread_area() deletion of an active segment

2016-04-29T09:56:42+00:00

Now that set_thread_area() is supposed to give deterministic behavior
when it modifies in-use segments, test it.

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: Thomas Gleixner 
Link: http://lkml.kernel.org/r/f2bc11af1ee1a0f815ed910840cbdba06b640a20.1461698311.git.luto@kernel.org
Signed-off-by: Ingo Molnar

selftests/x86: Test the FSBASE/GSBASE API and context switching

2016-04-13T08:20:41+00:00

This catches two distinct bugs in the current code.  I'll fix them.

Signed-off-by: Andy Lutomirski 
Reviewed-by: Borislav Petkov 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Rudolf Marek 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/7e5941148d1e2199f070dadcdf7355959f5f8e85.1460075211.git.luto@kernel.org
Signed-off-by: Ingo Molnar

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