Commit Graph

11 Commits

Author SHA1 Message Date
Mathieu Desnoyers
a4312e2d81 selftests/rseq: Fix: work-around asm goto compiler bugs
commit b53823fb2ef854222853be164f3b1e815f315144 upstream.

gcc and clang each have their own compiler bugs with respect to asm
goto. Implement a work-around for compiler versions known to have those
bugs.

gcc prior to 4.8.2 miscompiles asm goto.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670

gcc prior to 8.1.0 miscompiles asm goto at O1.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103908

clang prior to version 13.0.1 miscompiles asm goto at O2.
https://github.com/llvm/llvm-project/issues/52735

Work around these issues by adding a volatile inline asm with
memory clobber in the fallthrough after the asm goto and at each
label target.  Emit this for all compilers in case other similar
issues are found in the future.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220124171253.22072-14-mathieu.desnoyers@efficios.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-07-07 17:52:22 +02:00
Mathieu Desnoyers
35c6f5047f selftests/rseq: Fix ppc32 offsets by using long rather than off_t
commit 26dc8a6d8e11552f3b797b5aafe01071ca32d692 upstream.

The semantic of off_t is for file offsets. We mean to use it as an
offset from a pointer. We really expect it to fit in a single register,
and not use a 64-bit type on 32-bit architectures.

Fix runtime issues on ppc32 where the offset is always 0 due to
inconsistency between the argument type (off_t -> 64-bit) and type
expected by the inline assembler (32-bit).

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220124171253.22072-11-mathieu.desnoyers@efficios.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-07-07 17:52:21 +02:00
Mathieu Desnoyers
d4f631ea2d selftests/rseq: Fix ppc32: wrong rseq_cs 32-bit field pointer on big endian
commit 24d1136a29da5953de5c0cbc6c83eb62a1e0bf14 upstream.

ppc32 incorrectly uses padding as rseq_cs pointer field. Fix this by
using the rseq_cs.arch.ptr field.

Use this field across all architectures.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220124171253.22072-9-mathieu.desnoyers@efficios.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-07-07 17:52:21 +02:00
Mathieu Desnoyers
4a78bf83e2 selftests/rseq: Introduce rseq_get_abi() helper
commit e546cd48ccc456074ddb8920732aef4af65d7ca7 upstream.

This is done in preparation for the selftest uplift to become compatible
with glibc-2.35.

glibc-2.35 exposes the rseq per-thread data in the TCB, accessible
at an offset from the thread pointer, rather than through an actual
Thread-Local Storage (TLS) variable, as the kernel selftests initially
expected.

Introduce a rseq_get_abi() helper, initially using the __rseq_abi
TLS variable, in preparation for changing this userspace ABI for one
which is compatible with glibc-2.35.

Note that the __rseq_abi TLS and glibc-2.35's ABI for per-thread data
cannot actively coexist in a process, because the kernel supports only
a single rseq registration per thread.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220124171253.22072-6-mathieu.desnoyers@efficios.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-07-07 17:52:21 +02:00
Linus Torvalds
4c7b63a32d Merge tag 'linux-kselftest-5.2-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest
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
  ...
2019-05-16 18:57:58 -07:00
Martin Schwidefsky
3d4d1f05bc rseq/selftests: s390: use trap4 for RSEQ_SIG
Use trap4 as the guard instruction for the restartable sequence abort
handler.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2019-05-07 15:32:14 -06:00
Mathieu Desnoyers
97b8be8168 rseq/selftests: s390: use jg instruction for jumps outside of the asm
The branch target range of the "j" instruction is 64K, which is not
enough for the general case.

Suggested-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Joel Fernandes <joelaf@google.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Dave Watson <davejwatson@fb.com>
CC: Will Deacon <will.deacon@arm.com>
CC: Shuah Khan <shuah@kernel.org>
CC: Andi Kleen <andi@firstfloor.org>
CC: linux-kselftest@vger.kernel.org
CC: "H . Peter Anvin" <hpa@zytor.com>
CC: Chris Lameter <cl@linux.com>
CC: Russell King <linux@arm.linux.org.uk>
CC: Michael Kerrisk <mtk.manpages@gmail.com>
CC: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>
CC: Paul Turner <pjt@google.com>
CC: Boqun Feng <boqun.feng@gmail.com>
CC: Josh Triplett <josh@joshtriplett.org>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: Ben Maurer <bmaurer@fb.com>
CC: linux-api@vger.kernel.org
CC: Andy Lutomirski <luto@amacapital.net>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2019-05-07 15:31:55 -06:00
Mathieu Desnoyers
a3e3131f94 rseq/selftests: Introduce __rseq_cs_ptr_array, rename __rseq_table to __rseq_cs
The entries within __rseq_table are aligned on 32 bytes due to
linux/rseq.h struct rseq_cs uapi requirements, but the start of the
__rseq_table section is not guaranteed to be 32-byte aligned. It can
cause padding to be added at the start of the section, which makes it
hard to use as an array of items by debuggers.

Considering that __rseq_table does not really consist of a table due to
the presence of padding, rename this section to __rseq_cs.

Create a new __rseq_cs_ptr_array section which contains 64-bit packed
pointers to entries within the __rseq_cs section.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Joel Fernandes <joelaf@google.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Dave Watson <davejwatson@fb.com>
CC: Will Deacon <will.deacon@arm.com>
CC: Shuah Khan <shuah@kernel.org>
CC: Andi Kleen <andi@firstfloor.org>
CC: linux-kselftest@vger.kernel.org
CC: "H . Peter Anvin" <hpa@zytor.com>
CC: Chris Lameter <cl@linux.com>
CC: Russell King <linux@arm.linux.org.uk>
CC: Michael Kerrisk <mtk.manpages@gmail.com>
CC: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>
CC: Paul Turner <pjt@google.com>
CC: Boqun Feng <boqun.feng@gmail.com>
CC: Josh Triplett <josh@joshtriplett.org>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: Ben Maurer <bmaurer@fb.com>
CC: linux-api@vger.kernel.org
CC: Andy Lutomirski <luto@amacapital.net>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2019-05-07 15:31:36 -06:00
Mathieu Desnoyers
4fe2088e16 rseq/selftests: Add __rseq_exit_point_array section for debuggers
Knowing all exit points is useful to assist debuggers stepping over the
rseq critical sections without requiring them to disassemble the content
of the critical section to figure out the exit points.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Joel Fernandes <joelaf@google.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Dave Watson <davejwatson@fb.com>
CC: Will Deacon <will.deacon@arm.com>
CC: Shuah Khan <shuah@kernel.org>
CC: Andi Kleen <andi@firstfloor.org>
CC: linux-kselftest@vger.kernel.org
CC: "H . Peter Anvin" <hpa@zytor.com>
CC: Chris Lameter <cl@linux.com>
CC: Russell King <linux@arm.linux.org.uk>
CC: Michael Kerrisk <mtk.manpages@gmail.com>
CC: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>
CC: Paul Turner <pjt@google.com>
CC: Boqun Feng <boqun.feng@gmail.com>
CC: Josh Triplett <josh@joshtriplett.org>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: Ben Maurer <bmaurer@fb.com>
CC: linux-api@vger.kernel.org
CC: Andy Lutomirski <luto@amacapital.net>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2019-05-07 15:31:13 -06:00
Martin Schwidefsky
e24e4712ef s390/rseq: use trap4 for RSEQ_SIG
Use trap4 as the guard instruction for the restartable sequence abort
handler.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-04-10 17:48:34 +02:00
Vasily Gorbik
4c14d1ce17 rseq/selftests: add s390 support
Implement support for s390 in the rseq selftests, in order to sanity
check the recently enabled rseq syscall. The Implementation covers both
64-bit and 31-bit mode.

Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-08-09 07:59:05 +02:00