[PATCH v18 15/15] selftests, arm64: add a selftest for passing tagged pointers to kernel
Amit Kachhap
Amit.Kachhap at arm.com
Mon Aug 26 09:09:16 UTC 2019
Hi,
On 8/23/19 11:19 PM, Cristian Marussi wrote:
>
> Hi
>
> On 23/08/2019 18:16, Andrey Konovalov wrote:
>> On Fri, Aug 23, 2019 at 3:56 PM Cristian Marussi
>> <cristian.marussi at arm.com> wrote:
>>>
>>> Hi Andrey
>>>
>>> On 24/06/2019 15:33, Andrey Konovalov wrote:
>>>> This patch is a part of a series that extends kernel ABI to allow to pass
>>>> tagged user pointers (with the top byte set to something else other than
>>>> 0x00) as syscall arguments.
>>>>
>>>> This patch adds a simple test, that calls the uname syscall with a
>>>> tagged user pointer as an argument. Without the kernel accepting tagged
>>>> user pointers the test fails with EFAULT.
>>>>
>>>> Signed-off-by: Andrey Konovalov <andreyknvl at google.com>
>>>> ---
>>>> tools/testing/selftests/arm64/.gitignore | 1 +
>>>> tools/testing/selftests/arm64/Makefile | 11 +++++++
>>>> .../testing/selftests/arm64/run_tags_test.sh | 12 ++++++++
>>>> tools/testing/selftests/arm64/tags_test.c | 29 +++++++++++++++++++
>>>> 4 files changed, 53 insertions(+)
>>>> create mode 100644 tools/testing/selftests/arm64/.gitignore
>>>> create mode 100644 tools/testing/selftests/arm64/Makefile
>>>> create mode 100755 tools/testing/selftests/arm64/run_tags_test.sh
>>>> create mode 100644 tools/testing/selftests/arm64/tags_test.c
>>>
>>> After building a fresh Kernel from arm64/for-next-core from scratch at:
>>>
>>> commit 239ab658bea3b387424501e7c416640d6752dc0c
>>> Merge: 6bfa3134bd3a 42d038c4fb00 1243cb6a676f d55c5f28afaf d06fa5a118f1 34b5560db40d
>>> Author: Will Deacon <will at kernel.org>
>>> Date: Thu Aug 22 18:23:53 2019 +0100
>>>
>>> Merge branches 'for-next/error-injection', 'for-next/tbi', 'for-next/psci-cpuidle', 'for-next/cpu-topology' and 'for-next/52-bit-kva' into for-next/core
>>>
>>>
>>> KSFT arm64 tests build is broken for me, both setting or not KBUILD_OUTPUT=
>>>
>>> 13:30 $ make TARGETS=arm64 kselftest-clean
>>> make[1]: Entering directory '/home/crimar01/ARM/dev/src/pdsw/out_linux'
>>> rm -f -r /home/crimar01/ARM/dev/src/pdsw/out_linux//kselftest/arm64/tags_test
>>> make[1]: Leaving directory '/home/crimar01/ARM/dev/src/pdsw/out_linux'
>>>
>>> ✔ ~/ARM/dev/src/pdsw/linux [arm64_for_next_core|…8⚑ 23]
>>>
>>> 13:30 $ make TARGETS=arm64 kselftest
>>> make[1]: Entering directory '/home/crimar01/ARM/dev/src/pdsw/out_linux'
>>> arch/arm64/Makefile:56: CROSS_COMPILE_COMPAT not defined or empty, the compat vDSO will not be built
>>> make --no-builtin-rules INSTALL_HDR_PATH=$BUILD/usr \
>>> ARCH=arm64 -C ../../.. headers_install
>>> HOSTCC scripts/basic/fixdep
>>> HOSTCC scripts/unifdef
>>> ...
>>> ...
>>> HDRINST usr/include/asm/msgbuf.h
>>> HDRINST usr/include/asm/shmbuf.h
>>> INSTALL /home/crimar01/ARM/dev/src/pdsw/out_linux//kselftest/usr/include
>>> /opt/toolchains/gcc-arm-8.3-2019.03-x86_64-aarch64-linux-gnu/bin/aarch64-linux-gnu-gcc tags_test.c -o /home/crimar01/ARM/dev/src/pdsw/out_linux//kselftest/arm64/tags_test
>>> tags_test.c: In function ‘main’:
>>> tags_test.c:21:12: error: ‘PR_SET_TAGGED_ADDR_CTRL’ undeclared (first use in this function); did you mean ‘PR_GET_TID_ADDRESS’?
>>> if (prctl(PR_SET_TAGGED_ADDR_CTRL, PR_TAGGED_ADDR_ENABLE, 0, 0, 0) == 0)
>>> ^~~~~~~~~~~~~~~~~~~~~~~
>>> PR_GET_TID_ADDRESS
>>> tags_test.c:21:12: note: each undeclared identifier is reported only once for each function it appears in
>>> tags_test.c:21:37: error: ‘PR_TAGGED_ADDR_ENABLE’ undeclared (first use in this function); did you mean ‘PR_GET_DUMPABLE’?
>>> if (prctl(PR_SET_TAGGED_ADDR_CTRL, PR_TAGGED_ADDR_ENABLE, 0, 0, 0) == 0)
>>> ^~~~~~~~~~~~~~~~~~~~~
>>> PR_GET_DUMPABLE
>>> ../lib.mk:138: recipe for target '/home/crimar01/ARM/dev/src/pdsw/out_linux//kselftest/arm64/tags_test' failed
>>> make[3]: *** [/home/crimar01/ARM/dev/src/pdsw/out_linux//kselftest/arm64/tags_test] Error 1
>>> Makefile:136: recipe for target 'all' failed
>>> make[2]: *** [all] Error 2
>>> /home/crimar01/ARM/dev/src/pdsw/linux/Makefile:1237: recipe for target 'kselftest' failed
>>> make[1]: *** [kselftest] Error 2
>>> make[1]: Leaving directory '/home/crimar01/ARM/dev/src/pdsw/out_linux'
>>> Makefile:179: recipe for target 'sub-make' failed
>>> make: *** [sub-make] Error 2
>>>
>>> Despite seeing KSFT installing Kernel Headers, they cannot be found.
>>>
>>> Fixing this patch like this make it work for me:
>>>
>>> diff --git a/tools/testing/selftests/arm64/Makefile b/tools/testing/selftests/arm64/Makefile
>>> index a61b2e743e99..f9f79fb272f0 100644
>>> --- a/tools/testing/selftests/arm64/Makefile
>>> +++ b/tools/testing/selftests/arm64/Makefile
>>> @@ -4,6 +4,7 @@
>>> ARCH ?= $(shell uname -m 2>/dev/null || echo not)
>>>
>>> ifneq (,$(filter $(ARCH),aarch64 arm64))
>>> +CFLAGS += -I../../../../usr/include/
>>> TEST_GEN_PROGS := tags_test
>>> TEST_PROGS := run_tags_test.sh
>>> endif
>>>
>>> but is not really a proper fix since it does NOT account for case in which you have
>>> installed the Kernel Headers in a non standard location like when you use KBUILD_OUTPUT.
>>>
>>> Am I missing something ?
>>
>> Hm, PR_SET_TAGGED_ADDR_CTRL is defined in include/uapi/linux/prctl.h,
>> and the test has #include <sys/prctl.h> so as long as you've updated
>> your kernel headers this should work.
>>
>> (I'm OOO next week, I'll see if I can reproduce this once I'm back).
>
> Ok. Thanks for the reply.
>
> I think I've got it in my local tree having cloned arm64/for-next-core:
>
> 18:32 $ egrep -A 10 PR_SET_TAG ./include/uapi/linux/prctl.h
> #define PR_SET_TAGGED_ADDR_CTRL 55
> #define PR_GET_TAGGED_ADDR_CTRL 56
> # define PR_TAGGED_ADDR_ENABLE (1UL << 0)
>
> #endif /* _LINUX_PRCTL_H */
>
> and Kernel header are locally installed in my kernel src dir (by KSFT indeed)
>
> 18:34 $ egrep -RA 10 PR_SET_TAG usr/include/
> usr/include/linux/prctl.h:#define PR_SET_TAGGED_ADDR_CTRL 55
> usr/include/linux/prctl.h-#define PR_GET_TAGGED_ADDR_CTRL 56
> usr/include/linux/prctl.h-# define PR_TAGGED_ADDR_ENABLE (1UL << 0)
> usr/include/linux/prctl.h-
> usr/include/linux/prctl.h-#endif /* _LINUX_PRCTL_H */
>
> but how are they supposed to be found if nor the test Makefile
> neither the KSFT Makefile who installs them pass any -I options to the
> compiler ?
> I suppose <sys/prctl.h> tries to include arch specific headers from the regular system path,
> but when you are cross-compiling ?
I guess for cross-compiling it picks from cross_compiler path include
headers path without explicitly displaying it in compilation logs.
>
> 18:34 $ make TARGETS=arm64 kselftest
> make[1]: Entering directory '/home/crimar01/ARM/dev/src/pdsw/out_linux'
> arch/arm64/Makefile:56: CROSS_COMPILE_COMPAT not defined or empty, the compat vDSO will not be built
> make --no-builtin-rules INSTALL_HDR_PATH=$BUILD/usr \
> ARCH=arm64 -C ../../.. headers_install
> INSTALL /home/crimar01/ARM/dev/src/pdsw/out_linux/kselftest/usr/include
> /opt/toolchains/gcc-arm-8.3-2019.03-x86_64-aarch64-linux-gnu/bin/aarch64-linux-gnu-gcc -Wall -O2 -g tags_test.c -o /home/crimar01/ARM/dev/src/pdsw/out_linux/kselftest/arm64/tags/tags_test
> tags_test.c: In function ‘main’:
> tags_test.c:20:12: error: ‘PR_SET_TAGGED_ADDR_CTRL’ undeclared (first use in this function); did you mean ‘PR_GET_TID_ADDRESS’?
> if (prctl(PR_SET_TAGGED_ADDR_CTRL, PR_TAGGED_ADDR_ENABLE, 0, 0, 0) == 0)
> ^~~~~~~~~~~~~~~~~~~~~~~
> PR_GET_TID_ADDRESS
> tags_test.c:20:12: note: each undeclared identifier is reported only once for each function it appears in
> tags_test.c:20:37: error: ‘PR_TAGGED_ADDR_ENABLE’ undeclared (first use in this function); did you mean ‘PR_GET_DUMPABLE’?
> if (prctl(PR_SET_TAGGED_ADDR_CTRL, PR_TAGGED_ADDR_ENABLE, 0, 0, 0) == 0)
> ^~~~~~~~~~~~~~~~~~~~~
> PR_GET_DUMPABLE
> ../../lib.mk:138: recipe for target '/home/crimar01/ARM/dev/src/pdsw/out_linux/kselftest/arm64/tags/tags_test' failed
> make[4]: *** [/home/crimar01/ARM/dev/src/pdsw/out_linux/kselftest/arm64/tags/tags_test] Error 1
> Makefile:19: recipe for target 'all' failed
> make[3]: *** [all] Error 2
> Makefile:137: recipe for target 'all' failed
> make[2]: *** [all] Error 2
> /home/crimar01/ARM/dev/src/pdsw/linux/Makefile:1236: recipe for target 'kselftest' failed
> make[1]: *** [kselftest] Error 2
> make[1]: Leaving directory '/home/crimar01/ARM/dev/src/pdsw/out_linux'
> Makefile:179: recipe for target 'sub-make' failed
> make: *** [sub-make] Error 2
>
>
> In fact many KSFT testcases seems to brutally add default headers path:
>
> tools/testing/selftests/memfd/Makefile:CFLAGS += -I../../../../include/uapi/
> tools/testing/selftests/memfd/Makefile:CFLAGS += -I../../../../include/
> tools/testing/selftests/memfd/Makefile:CFLAGS += -I../../../../usr/include/
> tools/testing/selftests/net/Makefile:CFLAGS += -I../../../../usr/include/
> tools/testing/selftests/membarrier/Makefile:CFLAGS += -g -I../../../../usr/include/
Agree with Cristian that including like this is better as it allows
freedom from toolchain with latest kernel headers. Anyway there are many
places where "/sys/prctl.h" is used.
//Amit
> ...
>
> Cheers
>
> Cristian
>>
>>
>>
>>>
>>> Thanks
>>>
>>> Cristian
>>>
>>>>
>>>> diff --git a/tools/testing/selftests/arm64/.gitignore b/tools/testing/selftests/arm64/.gitignore
>>>> new file mode 100644
>>>> index 000000000000..e8fae8d61ed6
>>>> --- /dev/null
>>>> +++ b/tools/testing/selftests/arm64/.gitignore
>>>> @@ -0,0 +1 @@
>>>> +tags_test
>>>> diff --git a/tools/testing/selftests/arm64/Makefile b/tools/testing/selftests/arm64/Makefile
>>>> new file mode 100644
>>>> index 000000000000..a61b2e743e99
>>>> --- /dev/null
>>>> +++ b/tools/testing/selftests/arm64/Makefile
>>>> @@ -0,0 +1,11 @@
>>>> +# SPDX-License-Identifier: GPL-2.0
>>>> +
>>>> +# ARCH can be overridden by the user for cross compiling
>>>> +ARCH ?= $(shell uname -m 2>/dev/null || echo not)
>>>> +
>>>> +ifneq (,$(filter $(ARCH),aarch64 arm64))
>>>> +TEST_GEN_PROGS := tags_test
>>>> +TEST_PROGS := run_tags_test.sh
>>>> +endif
>>>> +
>>>> +include ../lib.mk
>>>> diff --git a/tools/testing/selftests/arm64/run_tags_test.sh b/tools/testing/selftests/arm64/run_tags_test.sh
>>>> new file mode 100755
>>>> index 000000000000..745f11379930
>>>> --- /dev/null
>>>> +++ b/tools/testing/selftests/arm64/run_tags_test.sh
>>>> @@ -0,0 +1,12 @@
>>>> +#!/bin/sh
>>>> +# SPDX-License-Identifier: GPL-2.0
>>>> +
>>>> +echo "--------------------"
>>>> +echo "running tags test"
>>>> +echo "--------------------"
>>>> +./tags_test
>>>> +if [ $? -ne 0 ]; then
>>>> + echo "[FAIL]"
>>>> +else
>>>> + echo "[PASS]"
>>>> +fi
>>>> diff --git a/tools/testing/selftests/arm64/tags_test.c b/tools/testing/selftests/arm64/tags_test.c
>>>> new file mode 100644
>>>> index 000000000000..22a1b266e373
>>>> --- /dev/null
>>>> +++ b/tools/testing/selftests/arm64/tags_test.c
>>>> @@ -0,0 +1,29 @@
>>>> +// SPDX-License-Identifier: GPL-2.0
>>>> +
>>>> +#include <stdio.h>
>>>> +#include <stdlib.h>
>>>> +#include <unistd.h>
>>>> +#include <stdint.h>
>>>> +#include <sys/prctl.h>
>>>> +#include <sys/utsname.h>
>>>> +
>>>> +#define SHIFT_TAG(tag) ((uint64_t)(tag) << 56)
>>>> +#define SET_TAG(ptr, tag) (((uint64_t)(ptr) & ~SHIFT_TAG(0xff)) | \
>>>> + SHIFT_TAG(tag))
>>>> +
>>>> +int main(void)
>>>> +{
>>>> + static int tbi_enabled = 0;
>>>> + struct utsname *ptr, *tagged_ptr;
>>>> + int err;
>>>> +
>>>> + if (prctl(PR_SET_TAGGED_ADDR_CTRL, PR_TAGGED_ADDR_ENABLE, 0, 0, 0) == 0)
>>>> + tbi_enabled = 1;
>>>> + ptr = (struct utsname *)malloc(sizeof(*ptr));
>>>> + if (tbi_enabled)
>>>> + tagged_ptr = (struct utsname *)SET_TAG(ptr, 0x42);
>>>> + err = uname(tagged_ptr);
>>>> + free(ptr);
>>>> +
>>>> + return err;
>>>> +}
>>>>
>>>
>
>
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