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From: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>
To: Yury Khrustalev <yury.khrustalev@arm.com>
Cc: libc-alpha@sourceware.org
Subject: Re: [PATCH 1/4] aarch64: Add tests for Guarded Control Stack
Date: Tue, 28 Jan 2025 08:49:00 -0300	[thread overview]
Message-ID: <d8800bc1-d461-4fae-bc9c-bc546c3d68bf@linaro.org> (raw)
In-Reply-To: <Z5isn1188y2KSTTP@arm.com>



On 28/01/25 07:08, Yury Khrustalev wrote:
> On Mon, Jan 27, 2025 at 05:47:21PM -0300, Adhemerval Zanella Netto wrote:
>>
>> On 23/01/25 11:13, Yury Khrustalev wrote:
>>> These tests validate that GCS tunable works as expected depending
>>> on the GCS markings in the test binaries.
>>>
>>> Tests validate both static and dynamically linked binaries.
>>>
>>> Test will build and run on AArch64 targets only and if GCS is not
>>> enabled on the platform running tests, they will be reported as
>>> UNSUPPORTED.
>>>
>>> When linking tests a new linker command line flag -z gcs=<value>
>>> is used. If the toolchain used to build these tests doesn't support
>>> this flag, there will be a warning that is expected and should be
>>> ignored.
>>
>> I think it would be better to add a configure check for '-z gcs=' support
>> and do not enable them if linker does not support it.
> 
> Such an option would only be needed for tests however it may give an
> impression that it can be used for the library code as well which would
> be incorrect. I'm not sure what is the best approach here but it would
> be good to use some sort of test-only configuration.

But this would be done automatically and only enabled during tests, as we
for various linker options on multiple Makefiles like have-test-stb-gnu-unique,
have-fpie, have-test-cc-trampoline, etc.  

I don't see much value in building a test that user will need to debug further 
to understand what it is failing (for instance on a system with HWCAP_GCS, but
without a toolchain that support -z gcs).

> 
>> Making them UNSUPPORTED might be somewhat misleading without also check the
>> build outout for '-z gcs=always ignored', because on systems with HWCAP_GCS 
>> it will result in some unexpect results for __check_gcs_status.
> 
> This is true, some of the tests will fail on such a system. I'm using assumption
> that the toolchain supports GCS if we intend to run tests on a system that has
> HWCAP_GCS.
> > Please note that there is v2 of this series:
> https://inbox.sourceware.org/libc-alpha/20250124122858.3788655-1-yury.khrustalev@arm.com/

Right, I missed that. I will focus on this version.

>  
>>> ---
>>>  sysdeps/unix/sysv/linux/aarch64/Makefile      | 64 +++++++++++++++++++
>>>  .../unix/sysv/linux/aarch64/tst-gcs-abort.sh  | 40 ++++++++++++
>>>  .../linux/aarch64/tst-gcs-disabled-static.c   |  1 +
>>>  .../sysv/linux/aarch64/tst-gcs-disabled.c     |  2 +
>>>  .../linux/aarch64/tst-gcs-enforced-abort.c    |  2 +
>>>  .../aarch64/tst-gcs-enforced-static-abort.c   |  1 +
>>>  .../linux/aarch64/tst-gcs-enforced-static.c   |  1 +
>>>  .../sysv/linux/aarch64/tst-gcs-enforced.c     |  2 +
>>>  .../sysv/linux/aarch64/tst-gcs-optional-off.c |  2 +
>>>  .../sysv/linux/aarch64/tst-gcs-optional-on.c  |  2 +
>>>  .../aarch64/tst-gcs-optional-static-off.c     |  1 +
>>>  .../aarch64/tst-gcs-optional-static-on.c      |  1 +
>>>  .../linux/aarch64/tst-gcs-override-static.c   |  1 +
>>>  .../sysv/linux/aarch64/tst-gcs-override.c     |  2 +
>>>  .../sysv/linux/aarch64/tst-gcs-skeleton.c     | 58 +++++++++++++++++
>>>  15 files changed, 180 insertions(+)
>>>  create mode 100644 sysdeps/unix/sysv/linux/aarch64/tst-gcs-abort.sh
>>>  create mode 100644 sysdeps/unix/sysv/linux/aarch64/tst-gcs-disabled-static.c
>>>  create mode 100644 sysdeps/unix/sysv/linux/aarch64/tst-gcs-disabled.c
>>>  create mode 100644 sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced-abort.c
>>>  create mode 100644 sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced-static-abort.c
>>>  create mode 100644 sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced-static.c
>>>  create mode 100644 sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced.c
>>>  create mode 100644 sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-off.c
>>>  create mode 100644 sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-on.c
>>>  create mode 100644 sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-static-off.c
>>>  create mode 100644 sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-static-on.c
>>>  create mode 100644 sysdeps/unix/sysv/linux/aarch64/tst-gcs-override-static.c
>>>  create mode 100644 sysdeps/unix/sysv/linux/aarch64/tst-gcs-override.c
>>>  create mode 100644 sysdeps/unix/sysv/linux/aarch64/tst-gcs-skeleton.c
>>>
>>> diff --git a/sysdeps/unix/sysv/linux/aarch64/Makefile b/sysdeps/unix/sysv/linux/aarch64/Makefile
>>> index 1fdad67fae..82a992bc14 100644
>>> --- a/sysdeps/unix/sysv/linux/aarch64/Makefile
>>> +++ b/sysdeps/unix/sysv/linux/aarch64/Makefile
>>> @@ -1,8 +1,72 @@
>>>  ifeq ($(subdir),misc)
>>>  sysdep_headers += sys/elf.h
>>> +
>>> +gcs-tests-dynamic = \
>>> +  tst-gcs-disabled \
>>> +  tst-gcs-enforced \
>>> +  tst-gcs-enforced-abort \
>>> +  tst-gcs-optional-off \
>>> +  tst-gcs-optional-on \
>>> +  tst-gcs-override \
>>> +  # gcs-tests-dynamic
>>> +
>>> +gcs-tests-static = \
>>> +  tst-gcs-disabled-static \
>>> +  tst-gcs-enforced-static \
>>> +  tst-gcs-enforced-static-abort \
>>> +  tst-gcs-optional-static-off \
>>> +  tst-gcs-optional-static-on \
>>> +  tst-gcs-override-static \
>>> +  # gcs-tests-static
>>> +
>>>  tests += \
>>> +  $(gcs-tests-dynamic) \
>>> +  $(gcs-tests-static) \
>>>    tst-aarch64-pkey \
>>>    # tests
>>> +
>>> +tests-static += \
>>> +  $(gcs-tests-static) \
>>> +  # tests-static
>>> +
>>> +define run-gcs-abort-test
>>> +  $(test-wrapper-env) $(run-program-env) \
>>> +  $(tst-gcs-$*-abort-ENV) $(host-test-program-cmd)
>>> +endef
>>> +
>>> +$(objpfx)tst-gcs-%-abort.out: $(..)sysdeps/unix/sysv/linux/aarch64/tst-gcs-abort.sh \
>>> +	$(objpfx)tst-gcs-%-abort
>>> +	$(SHELL) $< $(common-objpfx) $(test-name) '$(run-gcs-abort-test)'; \
>>> +	$(evaluate-test)
>>> +
>>> +LDFLAGS-tst-gcs-disabled += -Wl,-z gcs=always
>>> +LDFLAGS-tst-gcs-enforced += -Wl,-z gcs=always
>>> +LDFLAGS-tst-gcs-enforced-abort += -Wl,-z gcs=never
>>> +LDFLAGS-tst-gcs-optional-on += -Wl,-z gcs=always
>>> +LDFLAGS-tst-gcs-optional-off += -Wl,-z gcs=never
>>> +LDFLAGS-tst-gcs-override += -Wl,-z gcs=never
>>> +
>>> +LDFLAGS-tst-gcs-disabled-static += -Wl,-z gcs=always
>>> +LDFLAGS-tst-gcs-enforced-static += -Wl,-z gcs=always
>>> +LDFLAGS-tst-gcs-enforced-static-abort += -Wl,-z gcs=never
>>> +LDFLAGS-tst-gcs-optional-static-on += -Wl,-z gcs=always
>>> +LDFLAGS-tst-gcs-optional-static-off += -Wl,-z gcs=never
>>> +LDFLAGS-tst-gcs-override-static += -Wl,-z gcs=never
>>> +
>>> +tst-gcs-disabled-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=0
>>> +tst-gcs-enforced-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=1
>>> +tst-gcs-enforced-abort-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=1
>>> +tst-gcs-optional-on-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=2
>>> +tst-gcs-optional-off-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=2
>>> +tst-gcs-override-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=3
>>> +
>>> +tst-gcs-disabled-static-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=0
>>> +tst-gcs-enforced-static-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=1
>>> +tst-gcs-enforced-static-abort-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=1
>>> +tst-gcs-optional-static-on-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=2
>>> +tst-gcs-optional-static-off-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=2
>>> +tst-gcs-override-static-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=3
>>> +
>>>  endif
>>>  
>>>  ifeq ($(subdir),stdlib)
>>> diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-abort.sh b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-abort.sh
>>> new file mode 100644
>>> index 0000000000..5c1889bfcd
>>> --- /dev/null
>>> +++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-abort.sh
>>> @@ -0,0 +1,40 @@
>>> +#!/bin/sh
>>> +# Test wrapper for AArch64 tests for GCS that are expected to abort.
>>> +# Copyright (C) 2001-2025 Free Software Foundation, Inc.
>>> +# This file is part of the GNU C Library.
>>> +
>>> +# The GNU C Library is free software; you can redistribute it and/or
>>> +# modify it under the terms of the GNU Lesser General Public
>>> +# License as published by the Free Software Foundation; either
>>> +# version 2.1 of the License, or (at your option) any later version.
>>> +
>>> +# The GNU C Library is distributed in the hope that it will be useful,
>>> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
>>> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>>> +# Lesser General Public License for more details.
>>> +
>>> +# You should have received a copy of the GNU Lesser General Public
>>> +# License along with the GNU C Library; if not, see
>>> +# <https://www.gnu.org/licenses/>.
>>> +
>>> +objpfx=$1; shift
>>> +tstname=$1; shift
>>> +tstrun=$1; shift
>>> +
>>> +logfile=$objpfx/$tstname.out
>>> +
>>> +rm -vf $logfile
>>> +touch $logfile
>>> +
>>> +${tstrun} 2>> $logfile >> $logfile; status=$?
>>> +
>>> +if test $status -eq 127 \
>>> +  && grep -q -w "not GCS compatible" "$logfile" ; then
>>> +  exit 0
>>> +elif test $status -eq 77; then
>>> +  exit 77
>>> +else
>>> +  echo "unexpected test output or exit status $status"
>>> +  exit 1
>>> +fi
>>> +
>>> diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-disabled-static.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-disabled-static.c
>>> new file mode 100644
>>> index 0000000000..c71d68cb86
>>> --- /dev/null
>>> +++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-disabled-static.c
>>> @@ -0,0 +1 @@
>>> +#include "tst-gcs-disabled.c"
>>> diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-disabled.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-disabled.c
>>> new file mode 100644
>>> index 0000000000..bd688785bb
>>> --- /dev/null
>>> +++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-disabled.c
>>> @@ -0,0 +1,2 @@
>>> +#define TEST_GCS_EXPECT_ENABLED 0
>>> +#include "tst-gcs-skeleton.c"
>>> diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced-abort.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced-abort.c
>>> new file mode 100644
>>> index 0000000000..608318f26d
>>> --- /dev/null
>>> +++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced-abort.c
>>> @@ -0,0 +1,2 @@
>>> +#define TEST_GCS_EXPECT_ENABLED 1
>>> +#include "tst-gcs-skeleton.c"
>>> diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced-static-abort.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced-static-abort.c
>>> new file mode 100644
>>> index 0000000000..c20a999f6b
>>> --- /dev/null
>>> +++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced-static-abort.c
>>> @@ -0,0 +1 @@
>>> +#include "tst-gcs-enforced-abort.c"
>>> diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced-static.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced-static.c
>>> new file mode 100644
>>> index 0000000000..bb39dada55
>>> --- /dev/null
>>> +++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced-static.c
>>> @@ -0,0 +1 @@
>>> +#include "tst-gcs-enforced.c"
>>> diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced.c
>>> new file mode 100644
>>> index 0000000000..608318f26d
>>> --- /dev/null
>>> +++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced.c
>>> @@ -0,0 +1,2 @@
>>> +#define TEST_GCS_EXPECT_ENABLED 1
>>> +#include "tst-gcs-skeleton.c"
>>> diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-off.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-off.c
>>> new file mode 100644
>>> index 0000000000..bd688785bb
>>> --- /dev/null
>>> +++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-off.c
>>> @@ -0,0 +1,2 @@
>>> +#define TEST_GCS_EXPECT_ENABLED 0
>>> +#include "tst-gcs-skeleton.c"
>>> diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-on.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-on.c
>>> new file mode 100644
>>> index 0000000000..608318f26d
>>> --- /dev/null
>>> +++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-on.c
>>> @@ -0,0 +1,2 @@
>>> +#define TEST_GCS_EXPECT_ENABLED 1
>>> +#include "tst-gcs-skeleton.c"
>>> diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-static-off.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-static-off.c
>>> new file mode 100644
>>> index 0000000000..54e3b9a0d5
>>> --- /dev/null
>>> +++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-static-off.c
>>> @@ -0,0 +1 @@
>>> +#include "tst-gcs-optional-off.c"
>>> diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-static-on.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-static-on.c
>>> new file mode 100644
>>> index 0000000000..11b884b429
>>> --- /dev/null
>>> +++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-static-on.c
>>> @@ -0,0 +1 @@
>>> +#include "tst-gcs-optional-on.c"
>>> diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-override-static.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-override-static.c
>>> new file mode 100644
>>> index 0000000000..09055dcdc4
>>> --- /dev/null
>>> +++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-override-static.c
>>> @@ -0,0 +1 @@
>>> +#include "tst-gcs-override.c"
>>> diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-override.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-override.c
>>> new file mode 100644
>>> index 0000000000..608318f26d
>>> --- /dev/null
>>> +++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-override.c
>>> @@ -0,0 +1,2 @@
>>> +#define TEST_GCS_EXPECT_ENABLED 1
>>> +#include "tst-gcs-skeleton.c"
>>> diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-skeleton.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-skeleton.c
>>> new file mode 100644
>>> index 0000000000..37692c96d0
>>> --- /dev/null
>>> +++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-skeleton.c
>>> @@ -0,0 +1,58 @@
>>> +/* AArch64 tests for GCS.
>>> +   Copyright (C) 2025 Free Software Foundation, Inc.
>>> +   This file is part of the GNU C Library.
>>> +
>>> +   The GNU C Library is free software; you can redistribute it and/or
>>> +   modify it under the terms of the GNU Lesser General Public
>>> +   License as published by the Free Software Foundation; either
>>> +   version 2.1 of the License, or (at your option) any later version.
>>> +
>>> +   The GNU C Library is distributed in the hope that it will be useful,
>>> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
>>> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>>> +   Lesser General Public License for more details.
>>> +
>>> +   You should have received a copy of the GNU Lesser General Public
>>> +   License along with the GNU C Library; if not, see
>>> +   <https://www.gnu.org/licenses/>.  */
>>> +
>>> +#include <support/check.h>
>>> +#include <support/support.h>
>>> +#include <support/test-driver.h>
>>> +
>>> +#include <stdio.h>
>>> +#include <sys/auxv.h>
>>> +
>>> +static bool __check_gcs_status (void)
>>> +{
>>> +  register unsigned long x16 asm ("x16");
>>> +  asm volatile (
>>> +    "mov	x16, #1 /* _CHKFEAT_GCS */\n"
>>> +    "hint	40 /* CHKFEAT_X16 */\n"
>>> +    : "=r" (x16));
>>> +  return x16 ^ 1;
>>> +}
>>> +
>>> +static int
>>> +do_test (void)
>>> +{
>>> +  /* Check if GCS could possible by enabled.  */
>>> +  if (!(getauxval (AT_HWCAP) & HWCAP_GCS))
>>> +    {
>>> +      puts ("kernel or CPU does not support GCS");
>>> +      return EXIT_UNSUPPORTED;
>>> +    }
>>> +  bool gcs_enabled = __check_gcs_status ();
>>> +  if (gcs_enabled)
>>> +    puts ("GCS enabled");
>>> +  else
>>> +    puts ("GCS not enabled");
>>> +#if TEST_GCS_EXPECT_ENABLED
>>> +  TEST_VERIFY (gcs_enabled);
>>> +#else
>>> +  TEST_VERIFY (!gcs_enabled);
>>> +#endif
>>> +  return 0;
>>> +}
>>> +
>>> +#include <support/test-driver.c>
>>
>> The rest looks ok.


  reply	other threads:[~2025-01-28 11:49 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-01-23 14:13 [PATCH 0/4] " Yury Khrustalev
2025-01-23 14:13 ` [PATCH 1/4] aarch64: " Yury Khrustalev
2025-01-27 20:47   ` Adhemerval Zanella Netto
2025-01-28 10:08     ` Yury Khrustalev
2025-01-28 11:49       ` Adhemerval Zanella Netto [this message]
2025-01-28 13:23         ` Yury Khrustalev
2025-01-28 14:28           ` Adhemerval Zanella Netto
2025-01-29  9:56             ` Yury Khrustalev
2025-01-23 14:13 ` [PATCH 2/4] aarch64: Add GCS tests for transitive dependencies Yury Khrustalev
2025-01-23 14:14 ` [PATCH 3/4] aarch64: Add GCS tests for dlopen Yury Khrustalev
2025-01-23 14:14 ` [PATCH 4/4] aarch64: Add GCS test with signal handler Yury Khrustalev

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