Re: Patch "selftests: vDSO: skip getrandom test if architecture is unsupported" has been added to the 6.11-stable tree

Re: Patch "selftests: vDSO: skip getrandom test if architecture is unsupported" has been added to the 6.11-stable tree

[Jason A. Donenfeld]

This is not stable material and I didn't mark it as such. Do not backport.

Re: Patch "selftests: vDSO: skip getrandom test if architecture is unsupported" has been added to the 6.11-stable tree

[Shuah Khan]

On 9/30/24 21:56, Jason A. Donenfeld wrote:
> This is not stable material and I didn't mark it as such. Do not backport.

The way selftest work is they just skip if a feature isn't supported.
As such this test should run gracefully on stable releases.

I would say backport unless and skip if the feature isn't supported.

Does this build on stables?

thanks,
-- Shuah

Re: Patch "selftests: vDSO: skip getrandom test if architecture is unsupported" has been added to the 6.11-stable tree

[Jason A. Donenfeld]

On Tue, Oct 01, 2024 at 08:43:05AM -0600, Shuah Khan wrote:
> On 9/30/24 21:56, Jason A. Donenfeld wrote:
> > This is not stable material and I didn't mark it as such. Do not backport.
> 
> The way selftest work is they just skip if a feature isn't supported.
> As such this test should run gracefully on stable releases.
> 
> I would say backport unless and skip if the feature isn't supported.

Nonsense. 6.11 never returns ENOSYS from vDSO. This doesn't make sense.

Re: Patch "selftests: vDSO: skip getrandom test if architecture is unsupported" has been added to the 6.11-stable tree

[Shuah Khan]

On 10/1/24 08:45, Jason A. Donenfeld wrote:
> On Tue, Oct 01, 2024 at 08:43:05AM -0600, Shuah Khan wrote:
>> On 9/30/24 21:56, Jason A. Donenfeld wrote:
>>> This is not stable material and I didn't mark it as such. Do not backport.
>>
>> The way selftest work is they just skip if a feature isn't supported.
>> As such this test should run gracefully on stable releases.
>>
>> I would say backport unless and skip if the feature isn't supported.
> 
> Nonsense. 6.11 never returns ENOSYS from vDSO. This doesn't make sense.

Not sure what you mean by Nonsense. ENOSYS can be used to skip??

thanks,
-- Shuah

Re: Patch "selftests: vDSO: skip getrandom test if architecture is unsupported" has been added to the 6.11-stable tree

[Jason A. Donenfeld]

On Tue, Oct 01, 2024 at 08:56:43AM -0600, Shuah Khan wrote:
> On 10/1/24 08:45, Jason A. Donenfeld wrote:
> > On Tue, Oct 01, 2024 at 08:43:05AM -0600, Shuah Khan wrote:
> >> On 9/30/24 21:56, Jason A. Donenfeld wrote:
> >>> This is not stable material and I didn't mark it as such. Do not backport.
> >>
> >> The way selftest work is they just skip if a feature isn't supported.
> >> As such this test should run gracefully on stable releases.
> >>
> >> I would say backport unless and skip if the feature isn't supported.
> > 
> > Nonsense. 6.11 never returns ENOSYS from vDSO. This doesn't make sense.
> 
> Not sure what you mean by Nonsense. ENOSYS can be used to skip??

The branch that this patch adds will never be reached in 6.11 because
the kernel does not have the corresponding code.

Re: Patch "selftests: vDSO: skip getrandom test if architecture is unsupported" has been added to the 6.11-stable tree

[Shuah Khan]

On 10/1/24 09:03, Jason A. Donenfeld wrote:
> On Tue, Oct 01, 2024 at 08:56:43AM -0600, Shuah Khan wrote:
>> On 10/1/24 08:45, Jason A. Donenfeld wrote:
>>> On Tue, Oct 01, 2024 at 08:43:05AM -0600, Shuah Khan wrote:
>>>> On 9/30/24 21:56, Jason A. Donenfeld wrote:
>>>>> This is not stable material and I didn't mark it as such. Do not backport.
>>>>
>>>> The way selftest work is they just skip if a feature isn't supported.
>>>> As such this test should run gracefully on stable releases.
>>>>
>>>> I would say backport unless and skip if the feature isn't supported.
>>>
>>> Nonsense. 6.11 never returns ENOSYS from vDSO. This doesn't make sense.
>>
>> Not sure what you mean by Nonsense. ENOSYS can be used to skip??
> 
> The branch that this patch adds will never be reached in 6.11 because
> the kernel does not have the corresponding code.

What should/would happen if this test is run on a kernel that doesn't
support the feature?

thanks,
-- Shuah

Re: Patch "selftests: vDSO: skip getrandom test if architecture is unsupported" has been added to the 6.11-stable tree

[Jason A. Donenfeld]

On Tue, Oct 01, 2024 at 09:29:45AM -0600, Shuah Khan wrote:
> On 10/1/24 09:03, Jason A. Donenfeld wrote:
> > On Tue, Oct 01, 2024 at 08:56:43AM -0600, Shuah Khan wrote:
> >> On 10/1/24 08:45, Jason A. Donenfeld wrote:
> >>> On Tue, Oct 01, 2024 at 08:43:05AM -0600, Shuah Khan wrote:
> >>>> On 9/30/24 21:56, Jason A. Donenfeld wrote:
> >>>>> This is not stable material and I didn't mark it as such. Do not backport.
> >>>>
> >>>> The way selftest work is they just skip if a feature isn't supported.
> >>>> As such this test should run gracefully on stable releases.
> >>>>
> >>>> I would say backport unless and skip if the feature isn't supported.
> >>>
> >>> Nonsense. 6.11 never returns ENOSYS from vDSO. This doesn't make sense.
> >>
> >> Not sure what you mean by Nonsense. ENOSYS can be used to skip??
> > 
> > The branch that this patch adds will never be reached in 6.11 because
> > the kernel does not have the corresponding code.
> 
> What should/would happen if this test is run on a kernel that doesn't
> support the feature?

The build system doesn't compile it for kernels without the feature.

Re: Patch "selftests: vDSO: skip getrandom test if architecture is unsupported" has been added to the 6.11-stable tree

[Greg KH]

On Wed, Oct 02, 2024 at 06:13:45AM +0200, Jason A. Donenfeld wrote:
> On Tue, Oct 01, 2024 at 09:29:45AM -0600, Shuah Khan wrote:
> > On 10/1/24 09:03, Jason A. Donenfeld wrote:
> > > On Tue, Oct 01, 2024 at 08:56:43AM -0600, Shuah Khan wrote:
> > >> On 10/1/24 08:45, Jason A. Donenfeld wrote:
> > >>> On Tue, Oct 01, 2024 at 08:43:05AM -0600, Shuah Khan wrote:
> > >>>> On 9/30/24 21:56, Jason A. Donenfeld wrote:
> > >>>>> This is not stable material and I didn't mark it as such. Do not backport.
> > >>>>
> > >>>> The way selftest work is they just skip if a feature isn't supported.
> > >>>> As such this test should run gracefully on stable releases.
> > >>>>
> > >>>> I would say backport unless and skip if the feature isn't supported.
> > >>>
> > >>> Nonsense. 6.11 never returns ENOSYS from vDSO. This doesn't make sense.
> > >>
> > >> Not sure what you mean by Nonsense. ENOSYS can be used to skip??
> > > 
> > > The branch that this patch adds will never be reached in 6.11 because
> > > the kernel does not have the corresponding code.
> > 
> > What should/would happen if this test is run on a kernel that doesn't
> > support the feature?
> 
> The build system doesn't compile it for kernels without the feature.
> 

That's not how the kselftests should be working.  They can run on any
kernel image (build is separate from running on many test systems), and
so they should just fail with whatever the "feature not present" error
is if the feature isn't present in the system-that-is-being-tested.

thanks,

greg k-h

Re: Patch "selftests: vDSO: skip getrandom test if architecture is unsupported" has been added to the 6.11-stable tree

[Jason A. Donenfeld]

On Wed, Oct 02, 2024 at 08:21:36AM +0200, Greg KH wrote:
> On Wed, Oct 02, 2024 at 06:13:45AM +0200, Jason A. Donenfeld wrote:
> > On Tue, Oct 01, 2024 at 09:29:45AM -0600, Shuah Khan wrote:
> > > On 10/1/24 09:03, Jason A. Donenfeld wrote:
> > > > On Tue, Oct 01, 2024 at 08:56:43AM -0600, Shuah Khan wrote:
> > > >> On 10/1/24 08:45, Jason A. Donenfeld wrote:
> > > >>> On Tue, Oct 01, 2024 at 08:43:05AM -0600, Shuah Khan wrote:
> > > >>>> On 9/30/24 21:56, Jason A. Donenfeld wrote:
> > > >>>>> This is not stable material and I didn't mark it as such. Do not backport.
> > > >>>>
> > > >>>> The way selftest work is they just skip if a feature isn't supported.
> > > >>>> As such this test should run gracefully on stable releases.
> > > >>>>
> > > >>>> I would say backport unless and skip if the feature isn't supported.
> > > >>>
> > > >>> Nonsense. 6.11 never returns ENOSYS from vDSO. This doesn't make sense.
> > > >>
> > > >> Not sure what you mean by Nonsense. ENOSYS can be used to skip??
> > > > 
> > > > The branch that this patch adds will never be reached in 6.11 because
> > > > the kernel does not have the corresponding code.
> > > 
> > > What should/would happen if this test is run on a kernel that doesn't
> > > support the feature?
> > 
> > The build system doesn't compile it for kernels without the feature.
> > 
> 
> That's not how the kselftests should be working.

If you'd like to get involved in the development of these, by all means
send patches. As you can see, for 6.12, these were intensely improved in
all manner of ways:

   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/tools/testing/selftests/vDSO

Just look at that flurry of activity. Things are getting better! And
things were in pretty bad shape before. If you think there's an
interesting subset of that for backporting, by all means go for it, but
do it thoughtfully and don't pick patches willy-nilly.

> They can run on any
> kernel image (build is separate from running on many test systems), and
> so they should just fail with whatever the "feature not present" error
> is if the feature isn't present in the system-that-is-being-tested.

So, it's actually not that clear what the best thing is. Firstly, for
vdso_test_chacha.c, it can't even compile without the symlink and a
resolving tools/arch/$(SRCARCH)/vdso/vgetrandom-chacha.S symlink, which
is on a per-arch basis. You might say that in this case, it's best to
condition the Makefile on `ifneq ($(wildcard tools/arch/$(SRCARCH)/vdso/
vgetrandom-chacha.S),)` instead of on $(ARCH), but there's this ugly
wrinkle where some of the code that's being compiled is 64-bit only, and
x86_64 and x86 share a $(SRCARCH) path. (That Makefile makes use of
$(CONFIG_X86_32), which is pretty gross and might not work; I'm not yet
sure how to fix that.) Christophe experimented with having the compiler
decide, and then there being a runtime result, but it added a lot of
complexity that didn't seem necessary. There's more experimentation to
be done here.

Meanwhile, part of vdso_test_getrandom.c's purpose is to test whether
__kernel_getrandom() or __vdso_getrandom() is actually being properly
exported from the vDSO. This is also interesting on powerpc, where it's
implemented on both 32-bit and 64-bit, so there's the compat case to
worry about. That in turn means that this test has in it:

	vgrnd.fn = (__typeof__(vgrnd.fn))vdso_sym(version, name);
	if (!vgrnd.fn) {
		printf("%s is missing!\n", name);
		exit(KSFT_FAIL);
	}

And not exit(KSFT_SKIP), since that would hide the failure to export the
symbol. Now, you could say that since development on the fundamental
part is mostly concluded, we could move to a KSFT_SKIP, in order to
simplify the build choice and such. I'm not sure where I stand on that.
At the very least, there's still RISC-V coming down the pipeline for
this feature, so it probably would change after that comes out.

Anyway, that is all to say that this stuff has been thoroughly
considered, not haphazardly glued together or something. Maybe that
consideration has reached wrong conclusions -- that's an entirely
possible of an outcome -- but it wouldn't be for lack of caring. If
you'd like to contribute to it, I'd certainly welcome a hand. But please
don't do the arm-chair coding thing.

Meanwhile, this ENOSYS thing has nothing to do with what either of you
assumed it does. This is to handle obscure/exotic arm64 hardware, which
might not exist in the Linux world, that doesn't have NEON support. But
since arm64 support for this function didn't even come to Linux 6.11,
there's no point in discussing it as a backport.

Jason

Re: Patch "selftests: vDSO: skip getrandom test if architecture is unsupported" has been added to the 6.11-stable tree

[Shuah Khan]

On 10/2/24 11:00, Jason A. Donenfeld wrote:
> On Wed, Oct 02, 2024 at 08:21:36AM +0200, Greg KH wrote:
>> On Wed, Oct 02, 2024 at 06:13:45AM +0200, Jason A. Donenfeld wrote:
>>> On Tue, Oct 01, 2024 at 09:29:45AM -0600, Shuah Khan wrote:
>>>> On 10/1/24 09:03, Jason A. Donenfeld wrote:
>>>>> On Tue, Oct 01, 2024 at 08:56:43AM -0600, Shuah Khan wrote:
>>>>>> On 10/1/24 08:45, Jason A. Donenfeld wrote:
>>>>>>> On Tue, Oct 01, 2024 at 08:43:05AM -0600, Shuah Khan wrote:
>>>>>>>> On 9/30/24 21:56, Jason A. Donenfeld wrote:
>>>>>>>>> This is not stable material and I didn't mark it as such. Do not backport.
>>>>>>>>
>>>>>>>> The way selftest work is they just skip if a feature isn't supported.
>>>>>>>> As such this test should run gracefully on stable releases.
>>>>>>>>
>>>>>>>> I would say backport unless and skip if the feature isn't supported.
>>>>>>>
>>>>>>> Nonsense. 6.11 never returns ENOSYS from vDSO. This doesn't make sense.
>>>>>>
>>>>>> Not sure what you mean by Nonsense. ENOSYS can be used to skip??
>>>>>
>>>>> The branch that this patch adds will never be reached in 6.11 because
>>>>> the kernel does not have the corresponding code.
>>>>
>>>> What should/would happen if this test is run on a kernel that doesn't
>>>> support the feature?
>>>
>>> The build system doesn't compile it for kernels without the feature.
>>>
>>
>> That's not how the kselftests should be working.
> 
> If you'd like to get involved in the development of these, by all means
> send patches. As you can see, for 6.12, these were intensely improved in
> all manner of ways:
> 
>     https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/tools/testing/selftests/vDSO
> 
> Just look at that flurry of activity. Things are getting better! And
> things were in pretty bad shape before. If you think there's an
> interesting subset of that for backporting, by all means go for it, but
> do it thoughtfully and don't pick patches willy-nilly.
> 

This is not different from other kernel APIs and enhancements and
correspo0nding updates to the existing selftests.

The
vdso_test_getrandom test a user-space program exists in 6.11.

Use should be able to run vdso_test_getrandom compiled on 6.12
repo on a 6.11 kernel.

>> They can run on any
>> kernel image (build is separate from running on many test systems), and
>> so they should just fail with whatever the "feature not present" error
>> is if the feature isn't present in the system-that-is-being-tested.
> 

vdso_test_getrandom test a user-space program exists in 6.11.
Users should be able to run vdso_test_getrandom compiled on 6.12
repo on a 6.11 kernel. This is what several CIs do.

> So, it's actually not that clear what the best thing is. Firstly, for
> vdso_test_chacha.c, it can't even compile without the symlink and a
> resolving tools/arch/$(SRCARCH)/vdso/vgetrandom-chacha.S symlink, which
> is on a per-arch basis. You might say that in this case, it's best to
> condition the Makefile on `ifneq ($(wildcard tools/arch/$(SRCARCH)/vdso/
> vgetrandom-chacha.S),)` instead of on $(ARCH), but there's this ugly
> wrinkle where some of the code that's being compiled is 64-bit only, and
> x86_64 and x86 share a $(SRCARCH) path. (That Makefile makes use of
> $(CONFIG_X86_32), which is pretty gross and might not work; I'm not yet
> sure how to fix that.) Christophe experimented with having the compiler
> decide, and then there being a runtime result, but it added a lot of
> complexity that didn't seem necessary. There's more experimentation to
> be done here.
> 
> Meanwhile, part of vdso_test_getrandom.c's purpose is to test whether
> __kernel_getrandom() or __vdso_getrandom() is actually being properly
> exported from the vDSO. This is also interesting on powerpc, where it's
> implemented on both 32-bit and 64-bit, so there's the compat case to
> worry about. That in turn means that this test has in it:
> 
> 	vgrnd.fn = (__typeof__(vgrnd.fn))vdso_sym(version, name);
> 	if (!vgrnd.fn) {
> 		printf("%s is missing!\n", name);
> 		exit(KSFT_FAIL);
> 	}
> 

x86 selftest handles 32 vs 64-bit related scenarios now. You can take
a look at the Makefile. You can also split the test specific to 32 vs
64 and compile it for native and cross-compile cases.

> And not exit(KSFT_SKIP), since that would hide the failure to export the
> symbol. Now, you could say that since development on the fundamental
> part is mostly concluded, we could move to a KSFT_SKIP, in order to
> simplify the build choice and such. I'm not sure where I stand on that.

If I am understanding this correctly, KSFT_FAIL is used during development
and as of today, KSFT_SKIP is the correct exit code??

> At the very least, there's still RISC-V coming down the pipeline for
> this feature, so it probably would change after that comes out.
> 

This can be handled as part RISC-V.

> Anyway, that is all to say that this stuff has been thoroughly
> considered, not haphazardly glued together or something. Maybe that
> consideration has reached wrong conclusions -- that's an entirely
> possible of an outcome -- but it wouldn't be for lack of caring. If
> you'd like to contribute to it, I'd certainly welcome a hand. But please
> don't do the arm-chair coding thing.
> 

Probably. We don't know what we don't know. selftest use-cases are the
ones we are discussing here.

You can check the kselftest use-cases and contribution guidelines
in kselftest.rst

> Meanwhile, this ENOSYS thing has nothing to do with what either of you
> assumed it does. This is to handle obscure/exotic arm64 hardware, which
> might not exist in the Linux world, that doesn't have NEON support. But
> since arm64 support for this function didn't even come to Linux 6.11,
> there's no point in discussing it as a backport.

#define ENOSYS          78      /* Function not implemented */

user-space understands ENOSYS as feature/function not implemented.

If ENOSYS is the right choice for this obscure/exotic arm64 hardware?

The user-space vdso_test_getrandom test has to run on all architectures
if can be compiled (unless Makefile restricts the compile) and older
releases and handle not finding the feature and fail gracefully.

thanks,
-- Shuah

Re: Patch "selftests: vDSO: skip getrandom test if architecture is unsupported" has been added to the 6.11-stable tree

[Jason A. Donenfeld]

On Wed, Oct 02, 2024 at 01:45:57PM -0600, Shuah Khan wrote:
> This is not different from other kernel APIs and enhancements and
> correspo0nding updates to the existing selftests.
> 
> The
> vdso_test_getrandom test a user-space program exists in 6.11.
> 
> Use should be able to run vdso_test_getrandom compiled on 6.12
> repo on a 6.11 kernel.
> vdso_test_getrandom test a user-space program exists in 6.11.
> Users should be able to run vdso_test_getrandom compiled on 6.12
> repo on a 6.11 kernel. This is what several CIs do.

The x86 test from 6.12 works just fine on 6.11.

I really don't follow you at all or what you're getting at. I think if
you actually look at the code, you'll be mostly okay with it. And if
there's something that looks awry to you, send a patch or describe to me
clearly what looks wrong and I'll send a patch.

[PATCH kselftest 0/3] getrandom & chacha cleanups

[Jason A. Donenfeld]

Hi Shuah,

I've now read your email several times trying to figure out what you
meant and what your objections are. This series is my best attempt at
trying to satisfy that. But my understanding still has a lot of question
marks, so I may have missed your point here. Nonetheless, maybe this
moves things forward a bit.

Jason

Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Greg KH <greg@kroah.com>

Jason A. Donenfeld (3):
  selftests: vDSO: condition chacha build on chacha implementation
  selftests: vDSO: unconditionally build getrandom test
  selftests: vDSO: improve getrandom and chacha error messages

 tools/testing/selftests/vDSO/Makefile         |  4 +-
 .../testing/selftests/vDSO/vdso_test_chacha.c | 27 ++++---
 .../selftests/vDSO/vdso_test_getrandom.c      | 75 ++++++++-----------
 3 files changed, 52 insertions(+), 54 deletions(-)

-- 
2.46.0

[PATCH kselftest 1/3] selftests: vDSO: condition chacha build on chacha implementation

[Jason A. Donenfeld]

The chacha test can build anywhere that the vgetrandom-chacha.S file is
available, so condition it on the existence of that file, rather than a
specific arch.

There is one wrinkle, which is that x86 and x86_64 are the same ARCH,
but the code is only functional for x86_64. So filter out the test for
CONFIG_X86_32 in the same block that the other 32-bit special case
lives.

We have to define top_srcdir ourselves, because even though lib.mk
defines it later, that has to be included after TEST_GEN_PROGS is
populated. Fortunately the definition is fairly trivial.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 tools/testing/selftests/vDSO/Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tools/testing/selftests/vDSO/Makefile b/tools/testing/selftests/vDSO/Makefile
index af9cedbf5357..2c38c9c6d056 100644
--- a/tools/testing/selftests/vDSO/Makefile
+++ b/tools/testing/selftests/vDSO/Makefile
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 include ../../../scripts/Makefile.arch
+top_srcdir = $(realpath ../../../..)
 
 TEST_GEN_PROGS := vdso_test_gettimeofday
 TEST_GEN_PROGS += vdso_test_getcpu
@@ -11,6 +12,8 @@ endif
 TEST_GEN_PROGS += vdso_test_correctness
 ifeq ($(ARCH)$(CONFIG_X86_32),$(filter $(ARCH)$(CONFIG_X86_32),x86 x86_64 loongarch arm64 powerpc s390))
 TEST_GEN_PROGS += vdso_test_getrandom
+endif
+ifneq ($(wildcard $(top_srcdir)/tools/arch/$(SRCARCH)/vdso/vgetrandom-chacha.S),)
 TEST_GEN_PROGS += vdso_test_chacha
 endif
 
@@ -18,6 +21,7 @@ CFLAGS := -std=gnu99 -O2
 
 ifeq ($(CONFIG_X86_32),y)
 LDLIBS += -lgcc_s
+TEST_GEN_PROGS := $(filter-out vdso_test_chacha,$(TEST_GEN_PROGS))
 endif
 
 include ../lib.mk
-- 
2.46.0

[PATCH kselftest 2/3] selftests: vDSO: unconditionally build getrandom test

[Jason A. Donenfeld]

Rather than building on supported archs, build on all archs, and then
use the presence of the symbol in the vDSO to either skip the test or
move forward with it.

Note that this means that this test no longer checks whether the symbol
was correctly added to the kernel. But hopefully this will be clear
enough to developers and we'll cross our fingers that symbols aren't
removed by accident and not caught after this change.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 tools/testing/selftests/vDSO/Makefile              | 2 --
 tools/testing/selftests/vDSO/vdso_test_getrandom.c | 2 +-
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/tools/testing/selftests/vDSO/Makefile b/tools/testing/selftests/vDSO/Makefile
index 2c38c9c6d056..96b4f2a766e2 100644
--- a/tools/testing/selftests/vDSO/Makefile
+++ b/tools/testing/selftests/vDSO/Makefile
@@ -10,9 +10,7 @@ ifeq ($(ARCH),$(filter $(ARCH),x86 x86_64))
 TEST_GEN_PROGS += vdso_standalone_test_x86
 endif
 TEST_GEN_PROGS += vdso_test_correctness
-ifeq ($(ARCH)$(CONFIG_X86_32),$(filter $(ARCH)$(CONFIG_X86_32),x86 x86_64 loongarch arm64 powerpc s390))
 TEST_GEN_PROGS += vdso_test_getrandom
-endif
 ifneq ($(wildcard $(top_srcdir)/tools/arch/$(SRCARCH)/vdso/vgetrandom-chacha.S),)
 TEST_GEN_PROGS += vdso_test_chacha
 endif
diff --git a/tools/testing/selftests/vDSO/vdso_test_getrandom.c b/tools/testing/selftests/vDSO/vdso_test_getrandom.c
index 72a1d9b43a84..5489a2f07434 100644
--- a/tools/testing/selftests/vDSO/vdso_test_getrandom.c
+++ b/tools/testing/selftests/vDSO/vdso_test_getrandom.c
@@ -119,7 +119,7 @@ static void vgetrandom_init(void)
 	vgrnd.fn = (__typeof__(vgrnd.fn))vdso_sym(version, name);
 	if (!vgrnd.fn) {
 		printf("%s is missing!\n", name);
-		exit(KSFT_FAIL);
+		exit(KSFT_SKIP);
 	}
 	ret = VDSO_CALL(vgrnd.fn, 5, NULL, 0, 0, &vgrnd.params, ~0UL);
 	if (ret == -ENOSYS) {
-- 
2.46.0

[PATCH kselftest 3/3] selftests: vDSO: improve getrandom and chacha error messages

[Jason A. Donenfeld]

Improve the error and skip condition messages to let the developer know
precisely where a test has failed. Also make better use of the ksft api
for this.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 .../testing/selftests/vDSO/vdso_test_chacha.c | 27 ++++---
 .../selftests/vDSO/vdso_test_getrandom.c      | 75 ++++++++-----------
 2 files changed, 49 insertions(+), 53 deletions(-)

diff --git a/tools/testing/selftests/vDSO/vdso_test_chacha.c b/tools/testing/selftests/vDSO/vdso_test_chacha.c
index b1ea532c5996..60c5ea5cb925 100644
--- a/tools/testing/selftests/vDSO/vdso_test_chacha.c
+++ b/tools/testing/selftests/vDSO/vdso_test_chacha.c
@@ -90,10 +90,8 @@ int main(int argc, char *argv[])
 	ksft_set_plan(1);
 
 	for (unsigned int trial = 0; trial < TRIALS; ++trial) {
-		if (getrandom(key, sizeof(key), 0) != sizeof(key)) {
-			printf("getrandom() failed!\n");
-			return KSFT_SKIP;
-		}
+		if (getrandom(key, sizeof(key), 0) != sizeof(key))
+			ksft_exit_skip("getrandom() failed unexpectedly\n");
 		memset(counter1, 0, sizeof(counter1));
 		reference_chacha20_blocks(output1, key, counter1, BLOCKS);
 		for (unsigned int split = 0; split < BLOCKS; ++split) {
@@ -102,8 +100,10 @@ int main(int argc, char *argv[])
 			if (split)
 				__arch_chacha20_blocks_nostack(output2, key, counter2, split);
 			__arch_chacha20_blocks_nostack(output2 + split * BLOCK_SIZE, key, counter2, BLOCKS - split);
-			if (memcmp(output1, output2, sizeof(output1)) || memcmp(counter1, counter2, sizeof(counter1)))
-				return KSFT_FAIL;
+			if (memcmp(output1, output2, sizeof(output1)))
+				ksft_exit_fail_msg("Main loop outputs do not match on trial %u, split %u\n", trial, split);
+			if (memcmp(counter1, counter2, sizeof(counter1)))
+				ksft_exit_fail_msg("Main loop counters do not match on trial %u, split %u\n", trial, split);
 		}
 	}
 	memset(counter1, 0, sizeof(counter1));
@@ -113,14 +113,19 @@ int main(int argc, char *argv[])
 
 	reference_chacha20_blocks(output1, key, counter1, BLOCKS);
 	__arch_chacha20_blocks_nostack(output2, key, counter2, BLOCKS);
-	if (memcmp(output1, output2, sizeof(output1)) || memcmp(counter1, counter2, sizeof(counter1)))
-		return KSFT_FAIL;
+	if (memcmp(output1, output2, sizeof(output1)))
+		ksft_exit_fail_msg("Block limit outputs do not match after first round\n");
+	if (memcmp(counter1, counter2, sizeof(counter1)))
+		ksft_exit_fail_msg("Block limit counters do not match after first round\n");
 
 	reference_chacha20_blocks(output1, key, counter1, BLOCKS);
 	__arch_chacha20_blocks_nostack(output2, key, counter2, BLOCKS);
-	if (memcmp(output1, output2, sizeof(output1)) || memcmp(counter1, counter2, sizeof(counter1)))
-		return KSFT_FAIL;
+	if (memcmp(output1, output2, sizeof(output1)))
+		ksft_exit_fail_msg("Block limit outputs do not match after second round\n");
+	if (memcmp(counter1, counter2, sizeof(counter1)))
+		ksft_exit_fail_msg("Block limit counters do not match after second round\n");
 
 	ksft_test_result_pass("chacha: PASS\n");
-	return KSFT_PASS;
+	ksft_exit_pass();
+	return 0;
 }
diff --git a/tools/testing/selftests/vDSO/vdso_test_getrandom.c b/tools/testing/selftests/vDSO/vdso_test_getrandom.c
index 5489a2f07434..f6f7054900ab 100644
--- a/tools/testing/selftests/vDSO/vdso_test_getrandom.c
+++ b/tools/testing/selftests/vDSO/vdso_test_getrandom.c
@@ -40,6 +40,9 @@
 	} while (0)
 #endif
 
+#define ksft_assert(condition) \
+	if (!(condition)) ksft_exit_fail_msg("Assertion failed: %s\n", #condition)
+
 static struct {
 	pthread_mutex_t lock;
 	void **states;
@@ -109,26 +112,19 @@ static void vgetrandom_init(void)
 	const char *version = versions[VDSO_VERSION];
 	const char *name = names[VDSO_NAMES][6];
 	unsigned long sysinfo_ehdr = getauxval(AT_SYSINFO_EHDR);
-	size_t ret;
+	ssize_t ret;
 
-	if (!sysinfo_ehdr) {
-		printf("AT_SYSINFO_EHDR is not present!\n");
-		exit(KSFT_SKIP);
-	}
+	if (!sysinfo_ehdr)
+		ksft_exit_skip("AT_SYSINFO_EHDR is not present\n");
 	vdso_init_from_sysinfo_ehdr(sysinfo_ehdr);
 	vgrnd.fn = (__typeof__(vgrnd.fn))vdso_sym(version, name);
-	if (!vgrnd.fn) {
-		printf("%s is missing!\n", name);
-		exit(KSFT_SKIP);
-	}
+	if (!vgrnd.fn)
+		ksft_exit_skip("%s@%s symbol is missing from vDSO\n", name, version);
 	ret = VDSO_CALL(vgrnd.fn, 5, NULL, 0, 0, &vgrnd.params, ~0UL);
-	if (ret == -ENOSYS) {
-		printf("unsupported architecture\n");
-		exit(KSFT_SKIP);
-	} else if (ret) {
-		printf("failed to fetch vgetrandom params!\n");
-		exit(KSFT_FAIL);
-	}
+	if (ret == -ENOSYS)
+		ksft_exit_skip("CPU does not have runtime support\n");
+	else if (ret)
+		ksft_exit_fail_msg("Failed to fetch vgetrandom params: %zd\n", ret);
 }
 
 static ssize_t vgetrandom(void *buf, size_t len, unsigned long flags)
@@ -137,10 +133,7 @@ static ssize_t vgetrandom(void *buf, size_t len, unsigned long flags)
 
 	if (!state) {
 		state = vgetrandom_get_state();
-		if (!state) {
-			printf("vgetrandom_get_state failed!\n");
-			exit(KSFT_FAIL);
-		}
+		ksft_assert(state);
 	}
 	return VDSO_CALL(vgrnd.fn, 5, buf, len, flags, state, vgrnd.params.size_of_opaque_state);
 }
@@ -152,7 +145,7 @@ static void *test_vdso_getrandom(void *ctx)
 	for (size_t i = 0; i < TRIALS; ++i) {
 		unsigned int val;
 		ssize_t ret = vgetrandom(&val, sizeof(val), 0);
-		assert(ret == sizeof(val));
+		ksft_assert(ret == sizeof(val));
 	}
 	return NULL;
 }
@@ -162,7 +155,7 @@ static void *test_libc_getrandom(void *ctx)
 	for (size_t i = 0; i < TRIALS; ++i) {
 		unsigned int val;
 		ssize_t ret = getrandom(&val, sizeof(val), 0);
-		assert(ret == sizeof(val));
+		ksft_assert(ret == sizeof(val));
 	}
 	return NULL;
 }
@@ -172,7 +165,7 @@ static void *test_syscall_getrandom(void *ctx)
 	for (size_t i = 0; i < TRIALS; ++i) {
 		unsigned int val;
 		ssize_t ret = syscall(__NR_getrandom, &val, sizeof(val), 0);
-		assert(ret == sizeof(val));
+		ksft_assert(ret == sizeof(val));
 	}
 	return NULL;
 }
@@ -207,7 +200,7 @@ static void bench_multi(void)
 
 	clock_gettime(CLOCK_MONOTONIC, &start);
 	for (size_t i = 0; i < THREADS; ++i)
-		assert(pthread_create(&threads[i], NULL, test_vdso_getrandom, NULL) == 0);
+		ksft_assert(pthread_create(&threads[i], NULL, test_vdso_getrandom, NULL) == 0);
 	for (size_t i = 0; i < THREADS; ++i)
 		pthread_join(threads[i], NULL);
 	clock_gettime(CLOCK_MONOTONIC, &end);
@@ -216,7 +209,7 @@ static void bench_multi(void)
 
 	clock_gettime(CLOCK_MONOTONIC, &start);
 	for (size_t i = 0; i < THREADS; ++i)
-		assert(pthread_create(&threads[i], NULL, test_libc_getrandom, NULL) == 0);
+		ksft_assert(pthread_create(&threads[i], NULL, test_libc_getrandom, NULL) == 0);
 	for (size_t i = 0; i < THREADS; ++i)
 		pthread_join(threads[i], NULL);
 	clock_gettime(CLOCK_MONOTONIC, &end);
@@ -225,7 +218,7 @@ static void bench_multi(void)
 
 	clock_gettime(CLOCK_MONOTONIC, &start);
 	for (size_t i = 0; i < THREADS; ++i)
-		assert(pthread_create(&threads[i], NULL, test_syscall_getrandom, NULL) == 0);
+		ksft_assert(pthread_create(&threads[i], NULL, test_syscall_getrandom, NULL) == 0);
 	for (size_t i = 0; i < THREADS; ++i)
 		pthread_join(threads[i], NULL);
 	clock_gettime(CLOCK_MONOTONIC, &end);
@@ -250,48 +243,46 @@ static void kselftest(void)
 
 	for (size_t i = 0; i < 1000; ++i) {
 		ssize_t ret = vgetrandom(weird_size, sizeof(weird_size), 0);
-		if (ret != sizeof(weird_size))
-			exit(KSFT_FAIL);
+		ksft_assert(ret == sizeof(weird_size));
 	}
 
 	ksft_test_result_pass("getrandom: PASS\n");
 
 	unshare(CLONE_NEWUSER);
-	assert(unshare(CLONE_NEWTIME) == 0);
+	ksft_assert(unshare(CLONE_NEWTIME) == 0);
 	child = fork();
-	assert(child >= 0);
+	ksft_assert(child >= 0);
 	if (!child) {
 		vgetrandom_init();
 		child = getpid();
-		assert(ptrace(PTRACE_TRACEME, 0, NULL, NULL) == 0);
-		assert(kill(child, SIGSTOP) == 0);
-		assert(vgetrandom(weird_size, sizeof(weird_size), 0) == sizeof(weird_size));
+		ksft_assert(ptrace(PTRACE_TRACEME, 0, NULL, NULL) == 0);
+		ksft_assert(kill(child, SIGSTOP) == 0);
+		ksft_assert(vgetrandom(weird_size, sizeof(weird_size), 0) == sizeof(weird_size));
 		_exit(0);
 	}
 	for (;;) {
 		struct ptrace_syscall_info info = { 0 };
 		int status, ret;
-		assert(waitpid(child, &status, 0) >= 0);
+		ksft_assert(waitpid(child, &status, 0) >= 0);
 		if (WIFEXITED(status)) {
-			if (WEXITSTATUS(status) != 0)
-				exit(KSFT_FAIL);
+			ksft_assert(WEXITSTATUS(status) == 0);
 			break;
 		}
-		assert(WIFSTOPPED(status));
+		ksft_assert(WIFSTOPPED(status));
 		if (WSTOPSIG(status) == SIGSTOP)
-			assert(ptrace(PTRACE_SETOPTIONS, child, 0, PTRACE_O_TRACESYSGOOD) == 0);
+			ksft_assert(ptrace(PTRACE_SETOPTIONS, child, 0, PTRACE_O_TRACESYSGOOD) == 0);
 		else if (WSTOPSIG(status) == (SIGTRAP | 0x80)) {
-			assert(ptrace(PTRACE_GET_SYSCALL_INFO, child, sizeof(info), &info) > 0);
+			ksft_assert(ptrace(PTRACE_GET_SYSCALL_INFO, child, sizeof(info), &info) > 0);
 			if (info.op == PTRACE_SYSCALL_INFO_ENTRY && info.entry.nr == __NR_getrandom &&
 			    info.entry.args[0] == (uintptr_t)weird_size && info.entry.args[1] == sizeof(weird_size))
-				exit(KSFT_FAIL);
+				ksft_exit_fail_msg("vgetrandom passed buffer to syscall getrandom unexpectedly\n");
 		}
-		assert(ptrace(PTRACE_SYSCALL, child, 0, 0) == 0);
+		ksft_assert(ptrace(PTRACE_SYSCALL, child, 0, 0) == 0);
 	}
 
 	ksft_test_result_pass("getrandom timens: PASS\n");
 
-	exit(KSFT_PASS);
+	ksft_exit_pass();
 }
 
 static void usage(const char *argv0)
-- 
2.46.0

Re: [PATCH kselftest 3/3] selftests: vDSO: improve getrandom and chacha error messages

[kernel test robot]

Hi Jason,

kernel test robot noticed the following build warnings:

[auto build test WARNING on shuah-kselftest/next]
[also build test WARNING on shuah-kselftest/fixes linus/master v6.12-rc1 next-20241004]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Jason-A-Donenfeld/selftests-vDSO-condition-chacha-build-on-chacha-implementation/20241003-111508
base:   https://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest.git next
patch link:    https://lore.kernel.org/r/20241003031307.2236454-4-Jason%40zx2c4.com
patch subject: [PATCH kselftest 3/3] selftests: vDSO: improve getrandom and chacha error messages
:::::: branch date: 2 days ago
:::::: commit date: 2 days ago
compiler: clang version 18.1.8 (https://github.com/llvm/llvm-project 3b5b5c1ec4a3095ab096dd780e84d7ab81f3d7ff)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241005/202410051432.uAzAV7yV-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/r/202410051432.uAzAV7yV-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> vdso_test_getrandom.c:274:3: warning: add explicit braces to avoid dangling else [-Wdangling-else]
     274 |                 else if (WSTOPSIG(status) == (SIGTRAP | 0x80)) {
         |                 ^
   1 warning generated.

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH kselftest 3/3] selftests: vDSO: improve getrandom and chacha error messages

[Jason A. Donenfeld]

I'll send a v2.

[PATCH kselftest v2 1/4] selftests: vDSO: condition chacha build on chacha implementation

[Jason A. Donenfeld]

The chacha test can build anywhere that the vgetrandom-chacha.S file is
available, so condition it on the existence of that file, rather than a
specific arch.

There is one wrinkle, which is that x86 and x86_64 are the same ARCH,
but the code is only functional for x86_64. So filter out the test for
CONFIG_X86_32 in the same block that the other 32-bit special case
lives.

We have to define top_srcdir ourselves, because even though lib.mk
defines it later, that has to be included after TEST_GEN_PROGS is
populated. Fortunately the definition is fairly trivial.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 tools/testing/selftests/vDSO/Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tools/testing/selftests/vDSO/Makefile b/tools/testing/selftests/vDSO/Makefile
index af9cedbf5357..2c38c9c6d056 100644
--- a/tools/testing/selftests/vDSO/Makefile
+++ b/tools/testing/selftests/vDSO/Makefile
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 include ../../../scripts/Makefile.arch
+top_srcdir = $(realpath ../../../..)
 
 TEST_GEN_PROGS := vdso_test_gettimeofday
 TEST_GEN_PROGS += vdso_test_getcpu
@@ -11,6 +12,8 @@ endif
 TEST_GEN_PROGS += vdso_test_correctness
 ifeq ($(ARCH)$(CONFIG_X86_32),$(filter $(ARCH)$(CONFIG_X86_32),x86 x86_64 loongarch arm64 powerpc s390))
 TEST_GEN_PROGS += vdso_test_getrandom
+endif
+ifneq ($(wildcard $(top_srcdir)/tools/arch/$(SRCARCH)/vdso/vgetrandom-chacha.S),)
 TEST_GEN_PROGS += vdso_test_chacha
 endif
 
@@ -18,6 +21,7 @@ CFLAGS := -std=gnu99 -O2
 
 ifeq ($(CONFIG_X86_32),y)
 LDLIBS += -lgcc_s
+TEST_GEN_PROGS := $(filter-out vdso_test_chacha,$(TEST_GEN_PROGS))
 endif
 
 include ../lib.mk
-- 
2.46.0

[PATCH kselftest v2 2/4] selftests: vDSO: unconditionally build getrandom test

[Jason A. Donenfeld]

Rather than building on supported archs, build on all archs, and then
use the presence of the symbol in the vDSO to either skip the test or
move forward with it.

Note that this means that this test no longer checks whether the symbol
was correctly added to the kernel. But hopefully this will be clear
enough to developers and we'll cross our fingers that symbols aren't
removed by accident and not caught after this change.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 tools/testing/selftests/vDSO/Makefile              | 2 --
 tools/testing/selftests/vDSO/vdso_test_getrandom.c | 2 +-
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/tools/testing/selftests/vDSO/Makefile b/tools/testing/selftests/vDSO/Makefile
index 2c38c9c6d056..96b4f2a766e2 100644
--- a/tools/testing/selftests/vDSO/Makefile
+++ b/tools/testing/selftests/vDSO/Makefile
@@ -10,9 +10,7 @@ ifeq ($(ARCH),$(filter $(ARCH),x86 x86_64))
 TEST_GEN_PROGS += vdso_standalone_test_x86
 endif
 TEST_GEN_PROGS += vdso_test_correctness
-ifeq ($(ARCH)$(CONFIG_X86_32),$(filter $(ARCH)$(CONFIG_X86_32),x86 x86_64 loongarch arm64 powerpc s390))
 TEST_GEN_PROGS += vdso_test_getrandom
-endif
 ifneq ($(wildcard $(top_srcdir)/tools/arch/$(SRCARCH)/vdso/vgetrandom-chacha.S),)
 TEST_GEN_PROGS += vdso_test_chacha
 endif
diff --git a/tools/testing/selftests/vDSO/vdso_test_getrandom.c b/tools/testing/selftests/vDSO/vdso_test_getrandom.c
index 72a1d9b43a84..5489a2f07434 100644
--- a/tools/testing/selftests/vDSO/vdso_test_getrandom.c
+++ b/tools/testing/selftests/vDSO/vdso_test_getrandom.c
@@ -119,7 +119,7 @@ static void vgetrandom_init(void)
 	vgrnd.fn = (__typeof__(vgrnd.fn))vdso_sym(version, name);
 	if (!vgrnd.fn) {
 		printf("%s is missing!\n", name);
-		exit(KSFT_FAIL);
+		exit(KSFT_SKIP);
 	}
 	ret = VDSO_CALL(vgrnd.fn, 5, NULL, 0, 0, &vgrnd.params, ~0UL);
 	if (ret == -ENOSYS) {
-- 
2.46.0

[PATCH kselftest v2 3/4] selftests: vDSO: improve getrandom and chacha error messages

[Jason A. Donenfeld]

Improve the error and skip condition messages to let the developer know
precisely where a test has failed. Also make better use of the ksft api
for this.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 .../testing/selftests/vDSO/vdso_test_chacha.c | 27 ++++---
 .../selftests/vDSO/vdso_test_getrandom.c      | 75 ++++++++-----------
 2 files changed, 49 insertions(+), 53 deletions(-)

diff --git a/tools/testing/selftests/vDSO/vdso_test_chacha.c b/tools/testing/selftests/vDSO/vdso_test_chacha.c
index b1ea532c5996..60c5ea5cb925 100644
--- a/tools/testing/selftests/vDSO/vdso_test_chacha.c
+++ b/tools/testing/selftests/vDSO/vdso_test_chacha.c
@@ -90,10 +90,8 @@ int main(int argc, char *argv[])
 	ksft_set_plan(1);
 
 	for (unsigned int trial = 0; trial < TRIALS; ++trial) {
-		if (getrandom(key, sizeof(key), 0) != sizeof(key)) {
-			printf("getrandom() failed!\n");
-			return KSFT_SKIP;
-		}
+		if (getrandom(key, sizeof(key), 0) != sizeof(key))
+			ksft_exit_skip("getrandom() failed unexpectedly\n");
 		memset(counter1, 0, sizeof(counter1));
 		reference_chacha20_blocks(output1, key, counter1, BLOCKS);
 		for (unsigned int split = 0; split < BLOCKS; ++split) {
@@ -102,8 +100,10 @@ int main(int argc, char *argv[])
 			if (split)
 				__arch_chacha20_blocks_nostack(output2, key, counter2, split);
 			__arch_chacha20_blocks_nostack(output2 + split * BLOCK_SIZE, key, counter2, BLOCKS - split);
-			if (memcmp(output1, output2, sizeof(output1)) || memcmp(counter1, counter2, sizeof(counter1)))
-				return KSFT_FAIL;
+			if (memcmp(output1, output2, sizeof(output1)))
+				ksft_exit_fail_msg("Main loop outputs do not match on trial %u, split %u\n", trial, split);
+			if (memcmp(counter1, counter2, sizeof(counter1)))
+				ksft_exit_fail_msg("Main loop counters do not match on trial %u, split %u\n", trial, split);
 		}
 	}
 	memset(counter1, 0, sizeof(counter1));
@@ -113,14 +113,19 @@ int main(int argc, char *argv[])
 
 	reference_chacha20_blocks(output1, key, counter1, BLOCKS);
 	__arch_chacha20_blocks_nostack(output2, key, counter2, BLOCKS);
-	if (memcmp(output1, output2, sizeof(output1)) || memcmp(counter1, counter2, sizeof(counter1)))
-		return KSFT_FAIL;
+	if (memcmp(output1, output2, sizeof(output1)))
+		ksft_exit_fail_msg("Block limit outputs do not match after first round\n");
+	if (memcmp(counter1, counter2, sizeof(counter1)))
+		ksft_exit_fail_msg("Block limit counters do not match after first round\n");
 
 	reference_chacha20_blocks(output1, key, counter1, BLOCKS);
 	__arch_chacha20_blocks_nostack(output2, key, counter2, BLOCKS);
-	if (memcmp(output1, output2, sizeof(output1)) || memcmp(counter1, counter2, sizeof(counter1)))
-		return KSFT_FAIL;
+	if (memcmp(output1, output2, sizeof(output1)))
+		ksft_exit_fail_msg("Block limit outputs do not match after second round\n");
+	if (memcmp(counter1, counter2, sizeof(counter1)))
+		ksft_exit_fail_msg("Block limit counters do not match after second round\n");
 
 	ksft_test_result_pass("chacha: PASS\n");
-	return KSFT_PASS;
+	ksft_exit_pass();
+	return 0;
 }
diff --git a/tools/testing/selftests/vDSO/vdso_test_getrandom.c b/tools/testing/selftests/vDSO/vdso_test_getrandom.c
index 5489a2f07434..50ec9ad4c7ec 100644
--- a/tools/testing/selftests/vDSO/vdso_test_getrandom.c
+++ b/tools/testing/selftests/vDSO/vdso_test_getrandom.c
@@ -40,6 +40,9 @@
 	} while (0)
 #endif
 
+#define ksft_assert(condition) \
+	do { if (!(condition)) ksft_exit_fail_msg("Assertion failed: %s\n", #condition); } while (0)
+
 static struct {
 	pthread_mutex_t lock;
 	void **states;
@@ -109,26 +112,19 @@ static void vgetrandom_init(void)
 	const char *version = versions[VDSO_VERSION];
 	const char *name = names[VDSO_NAMES][6];
 	unsigned long sysinfo_ehdr = getauxval(AT_SYSINFO_EHDR);
-	size_t ret;
+	ssize_t ret;
 
-	if (!sysinfo_ehdr) {
-		printf("AT_SYSINFO_EHDR is not present!\n");
-		exit(KSFT_SKIP);
-	}
+	if (!sysinfo_ehdr)
+		ksft_exit_skip("AT_SYSINFO_EHDR is not present\n");
 	vdso_init_from_sysinfo_ehdr(sysinfo_ehdr);
 	vgrnd.fn = (__typeof__(vgrnd.fn))vdso_sym(version, name);
-	if (!vgrnd.fn) {
-		printf("%s is missing!\n", name);
-		exit(KSFT_SKIP);
-	}
+	if (!vgrnd.fn)
+		ksft_exit_skip("%s@%s symbol is missing from vDSO\n", name, version);
 	ret = VDSO_CALL(vgrnd.fn, 5, NULL, 0, 0, &vgrnd.params, ~0UL);
-	if (ret == -ENOSYS) {
-		printf("unsupported architecture\n");
-		exit(KSFT_SKIP);
-	} else if (ret) {
-		printf("failed to fetch vgetrandom params!\n");
-		exit(KSFT_FAIL);
-	}
+	if (ret == -ENOSYS)
+		ksft_exit_skip("CPU does not have runtime support\n");
+	else if (ret)
+		ksft_exit_fail_msg("Failed to fetch vgetrandom params: %zd\n", ret);
 }
 
 static ssize_t vgetrandom(void *buf, size_t len, unsigned long flags)
@@ -137,10 +133,7 @@ static ssize_t vgetrandom(void *buf, size_t len, unsigned long flags)
 
 	if (!state) {
 		state = vgetrandom_get_state();
-		if (!state) {
-			printf("vgetrandom_get_state failed!\n");
-			exit(KSFT_FAIL);
-		}
+		ksft_assert(state);
 	}
 	return VDSO_CALL(vgrnd.fn, 5, buf, len, flags, state, vgrnd.params.size_of_opaque_state);
 }
@@ -152,7 +145,7 @@ static void *test_vdso_getrandom(void *ctx)
 	for (size_t i = 0; i < TRIALS; ++i) {
 		unsigned int val;
 		ssize_t ret = vgetrandom(&val, sizeof(val), 0);
-		assert(ret == sizeof(val));
+		ksft_assert(ret == sizeof(val));
 	}
 	return NULL;
 }
@@ -162,7 +155,7 @@ static void *test_libc_getrandom(void *ctx)
 	for (size_t i = 0; i < TRIALS; ++i) {
 		unsigned int val;
 		ssize_t ret = getrandom(&val, sizeof(val), 0);
-		assert(ret == sizeof(val));
+		ksft_assert(ret == sizeof(val));
 	}
 	return NULL;
 }
@@ -172,7 +165,7 @@ static void *test_syscall_getrandom(void *ctx)
 	for (size_t i = 0; i < TRIALS; ++i) {
 		unsigned int val;
 		ssize_t ret = syscall(__NR_getrandom, &val, sizeof(val), 0);
-		assert(ret == sizeof(val));
+		ksft_assert(ret == sizeof(val));
 	}
 	return NULL;
 }
@@ -207,7 +200,7 @@ static void bench_multi(void)
 
 	clock_gettime(CLOCK_MONOTONIC, &start);
 	for (size_t i = 0; i < THREADS; ++i)
-		assert(pthread_create(&threads[i], NULL, test_vdso_getrandom, NULL) == 0);
+		ksft_assert(pthread_create(&threads[i], NULL, test_vdso_getrandom, NULL) == 0);
 	for (size_t i = 0; i < THREADS; ++i)
 		pthread_join(threads[i], NULL);
 	clock_gettime(CLOCK_MONOTONIC, &end);
@@ -216,7 +209,7 @@ static void bench_multi(void)
 
 	clock_gettime(CLOCK_MONOTONIC, &start);
 	for (size_t i = 0; i < THREADS; ++i)
-		assert(pthread_create(&threads[i], NULL, test_libc_getrandom, NULL) == 0);
+		ksft_assert(pthread_create(&threads[i], NULL, test_libc_getrandom, NULL) == 0);
 	for (size_t i = 0; i < THREADS; ++i)
 		pthread_join(threads[i], NULL);
 	clock_gettime(CLOCK_MONOTONIC, &end);
@@ -225,7 +218,7 @@ static void bench_multi(void)
 
 	clock_gettime(CLOCK_MONOTONIC, &start);
 	for (size_t i = 0; i < THREADS; ++i)
-		assert(pthread_create(&threads[i], NULL, test_syscall_getrandom, NULL) == 0);
+		ksft_assert(pthread_create(&threads[i], NULL, test_syscall_getrandom, NULL) == 0);
 	for (size_t i = 0; i < THREADS; ++i)
 		pthread_join(threads[i], NULL);
 	clock_gettime(CLOCK_MONOTONIC, &end);
@@ -250,48 +243,46 @@ static void kselftest(void)
 
 	for (size_t i = 0; i < 1000; ++i) {
 		ssize_t ret = vgetrandom(weird_size, sizeof(weird_size), 0);
-		if (ret != sizeof(weird_size))
-			exit(KSFT_FAIL);
+		ksft_assert(ret == sizeof(weird_size));
 	}
 
 	ksft_test_result_pass("getrandom: PASS\n");
 
 	unshare(CLONE_NEWUSER);
-	assert(unshare(CLONE_NEWTIME) == 0);
+	ksft_assert(unshare(CLONE_NEWTIME) == 0);
 	child = fork();
-	assert(child >= 0);
+	ksft_assert(child >= 0);
 	if (!child) {
 		vgetrandom_init();
 		child = getpid();
-		assert(ptrace(PTRACE_TRACEME, 0, NULL, NULL) == 0);
-		assert(kill(child, SIGSTOP) == 0);
-		assert(vgetrandom(weird_size, sizeof(weird_size), 0) == sizeof(weird_size));
+		ksft_assert(ptrace(PTRACE_TRACEME, 0, NULL, NULL) == 0);
+		ksft_assert(kill(child, SIGSTOP) == 0);
+		ksft_assert(vgetrandom(weird_size, sizeof(weird_size), 0) == sizeof(weird_size));
 		_exit(0);
 	}
 	for (;;) {
 		struct ptrace_syscall_info info = { 0 };
 		int status, ret;
-		assert(waitpid(child, &status, 0) >= 0);
+		ksft_assert(waitpid(child, &status, 0) >= 0);
 		if (WIFEXITED(status)) {
-			if (WEXITSTATUS(status) != 0)
-				exit(KSFT_FAIL);
+			ksft_assert(WEXITSTATUS(status) == 0);
 			break;
 		}
-		assert(WIFSTOPPED(status));
+		ksft_assert(WIFSTOPPED(status));
 		if (WSTOPSIG(status) == SIGSTOP)
-			assert(ptrace(PTRACE_SETOPTIONS, child, 0, PTRACE_O_TRACESYSGOOD) == 0);
+			ksft_assert(ptrace(PTRACE_SETOPTIONS, child, 0, PTRACE_O_TRACESYSGOOD) == 0);
 		else if (WSTOPSIG(status) == (SIGTRAP | 0x80)) {
-			assert(ptrace(PTRACE_GET_SYSCALL_INFO, child, sizeof(info), &info) > 0);
+			ksft_assert(ptrace(PTRACE_GET_SYSCALL_INFO, child, sizeof(info), &info) > 0);
 			if (info.op == PTRACE_SYSCALL_INFO_ENTRY && info.entry.nr == __NR_getrandom &&
 			    info.entry.args[0] == (uintptr_t)weird_size && info.entry.args[1] == sizeof(weird_size))
-				exit(KSFT_FAIL);
+				ksft_exit_fail_msg("vgetrandom passed buffer to syscall getrandom unexpectedly\n");
 		}
-		assert(ptrace(PTRACE_SYSCALL, child, 0, 0) == 0);
+		ksft_assert(ptrace(PTRACE_SYSCALL, child, 0, 0) == 0);
 	}
 
 	ksft_test_result_pass("getrandom timens: PASS\n");
 
-	exit(KSFT_PASS);
+	ksft_exit_pass();
 }
 
 static void usage(const char *argv0)
-- 
2.46.0

[PATCH kselftest v2 4/4] selftests: vDSO: unconditionally build chacha test

[Jason A. Donenfeld]

Rather than using symlinks to find the vgetrandom-chacha.S file for each
arch, store this in a file that uses the compiler to determine
architecture, and then make use of weak symbols to skip the test on
architectures that don't provide the code.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 tools/arch/arm64/vdso                            |  1 -
 tools/arch/loongarch/vdso                        |  1 -
 tools/arch/powerpc/vdso                          |  1 -
 tools/arch/s390/vdso                             |  1 -
 tools/arch/x86/vdso                              |  1 -
 tools/testing/selftests/vDSO/Makefile            |  6 +-----
 tools/testing/selftests/vDSO/vdso_test_chacha.c  |  6 ++++++
 .../selftests/vDSO/vgetrandom-chacha-finder.S    | 16 ++++++++++++++++
 8 files changed, 23 insertions(+), 10 deletions(-)
 delete mode 120000 tools/arch/arm64/vdso
 delete mode 120000 tools/arch/loongarch/vdso
 delete mode 120000 tools/arch/powerpc/vdso
 delete mode 120000 tools/arch/s390/vdso
 delete mode 120000 tools/arch/x86/vdso
 create mode 100644 tools/testing/selftests/vDSO/vgetrandom-chacha-finder.S

diff --git a/tools/arch/arm64/vdso b/tools/arch/arm64/vdso
deleted file mode 120000
index 233c7a26f6e5..000000000000
--- a/tools/arch/arm64/vdso
+++ /dev/null
@@ -1 +0,0 @@
-../../../arch/arm64/kernel/vdso
\ No newline at end of file
diff --git a/tools/arch/loongarch/vdso b/tools/arch/loongarch/vdso
deleted file mode 120000
index ebda43a82db7..000000000000
--- a/tools/arch/loongarch/vdso
+++ /dev/null
@@ -1 +0,0 @@
-../../../arch/loongarch/vdso
\ No newline at end of file
diff --git a/tools/arch/powerpc/vdso b/tools/arch/powerpc/vdso
deleted file mode 120000
index 4e676d1d1cb4..000000000000
--- a/tools/arch/powerpc/vdso
+++ /dev/null
@@ -1 +0,0 @@
-../../../arch/powerpc/kernel/vdso
\ No newline at end of file
diff --git a/tools/arch/s390/vdso b/tools/arch/s390/vdso
deleted file mode 120000
index 6cf4c1cebdcd..000000000000
--- a/tools/arch/s390/vdso
+++ /dev/null
@@ -1 +0,0 @@
-../../../arch/s390/kernel/vdso64
\ No newline at end of file
diff --git a/tools/arch/x86/vdso b/tools/arch/x86/vdso
deleted file mode 120000
index 7eb962fd3454..000000000000
--- a/tools/arch/x86/vdso
+++ /dev/null
@@ -1 +0,0 @@
-../../../arch/x86/entry/vdso/
\ No newline at end of file
diff --git a/tools/testing/selftests/vDSO/Makefile b/tools/testing/selftests/vDSO/Makefile
index 96b4f2a766e2..e453c178d97f 100644
--- a/tools/testing/selftests/vDSO/Makefile
+++ b/tools/testing/selftests/vDSO/Makefile
@@ -1,6 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
 include ../../../scripts/Makefile.arch
-top_srcdir = $(realpath ../../../..)
 
 TEST_GEN_PROGS := vdso_test_gettimeofday
 TEST_GEN_PROGS += vdso_test_getcpu
@@ -11,15 +10,12 @@ TEST_GEN_PROGS += vdso_standalone_test_x86
 endif
 TEST_GEN_PROGS += vdso_test_correctness
 TEST_GEN_PROGS += vdso_test_getrandom
-ifneq ($(wildcard $(top_srcdir)/tools/arch/$(SRCARCH)/vdso/vgetrandom-chacha.S),)
 TEST_GEN_PROGS += vdso_test_chacha
-endif
 
 CFLAGS := -std=gnu99 -O2
 
 ifeq ($(CONFIG_X86_32),y)
 LDLIBS += -lgcc_s
-TEST_GEN_PROGS := $(filter-out vdso_test_chacha,$(TEST_GEN_PROGS))
 endif
 
 include ../lib.mk
@@ -39,7 +35,7 @@ $(OUTPUT)/vdso_test_getrandom: CFLAGS += -isystem $(top_srcdir)/tools/include \
                                          $(KHDR_INCLUDES) \
                                          -isystem $(top_srcdir)/include/uapi
 
-$(OUTPUT)/vdso_test_chacha: $(top_srcdir)/tools/arch/$(SRCARCH)/vdso/vgetrandom-chacha.S
+$(OUTPUT)/vdso_test_chacha: vgetrandom-chacha-finder.S
 $(OUTPUT)/vdso_test_chacha: CFLAGS += -idirafter $(top_srcdir)/tools/include \
                                       -idirafter $(top_srcdir)/tools/include/generated \
                                       -idirafter $(top_srcdir)/arch/$(SRCARCH)/include \
diff --git a/tools/testing/selftests/vDSO/vdso_test_chacha.c b/tools/testing/selftests/vDSO/vdso_test_chacha.c
index 60c5ea5cb925..e68f1cd4ebcf 100644
--- a/tools/testing/selftests/vDSO/vdso_test_chacha.c
+++ b/tools/testing/selftests/vDSO/vdso_test_chacha.c
@@ -78,6 +78,12 @@ typedef uint32_t u32;
 typedef uint64_t u64;
 #include <vdso/getrandom.h>
 
+__attribute__((weak))
+void __arch_chacha20_blocks_nostack(u8 *dst_bytes, const u32 *key, u32 *counter, size_t nblocks)
+{
+	ksft_exit_skip("Not implemented on architecture\n");
+}
+
 int main(int argc, char *argv[])
 {
 	enum { TRIALS = 1000, BLOCKS = 128, BLOCK_SIZE = 64 };
diff --git a/tools/testing/selftests/vDSO/vgetrandom-chacha-finder.S b/tools/testing/selftests/vDSO/vgetrandom-chacha-finder.S
new file mode 100644
index 000000000000..1ca240ddaab7
--- /dev/null
+++ b/tools/testing/selftests/vDSO/vgetrandom-chacha-finder.S
@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+
+#if defined(__aarch64__)
+#include "../../../../arch/arm64/kernel/vdso/vgetrandom-chacha.S"
+#elif defined(__loongarch__)
+#include "../../../../arch/loongarch/vdso/vgetrandom-chacha.S"
+#elif defined(__powerpc__) || defined(__powerpc64__)
+#include "../../../../arch/powerpc/kernel/vdso/vgetrandom-chacha.S"
+#elif defined(__s390x__)
+#include "../../../../arch/s390/kernel/vdso64/vgetrandom-chacha.S"
+#elif defined(__x86_64__)
+#include "../../../../arch/x86/entry/vdso/vgetrandom-chacha.S"
+#endif
-- 
2.46.0

Re: [PATCH kselftest v2 4/4] selftests: vDSO: unconditionally build chacha test

[Shuah Khan]

On 10/5/24 22:40, Jason A. Donenfeld wrote:
> Rather than using symlinks to find the vgetrandom-chacha.S file for each
> arch, store this in a file that uses the compiler to determine
> architecture, and then make use of weak symbols to skip the test on
> architectures that don't provide the code.
> 
> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
> ---
>   tools/arch/arm64/vdso                            |  1 -
>   tools/arch/loongarch/vdso                        |  1 -
>   tools/arch/powerpc/vdso                          |  1 -
>   tools/arch/s390/vdso                             |  1 -
>   tools/arch/x86/vdso                              |  1 -
>   tools/testing/selftests/vDSO/Makefile            |  6 +-----
>   tools/testing/selftests/vDSO/vdso_test_chacha.c  |  6 ++++++
>   .../selftests/vDSO/vgetrandom-chacha-finder.S    | 16 ++++++++++++++++
>   8 files changed, 23 insertions(+), 10 deletions(-)
>   delete mode 120000 tools/arch/arm64/vdso
>   delete mode 120000 tools/arch/loongarch/vdso
>   delete mode 120000 tools/arch/powerpc/vdso
>   delete mode 120000 tools/arch/s390/vdso
>   delete mode 120000 tools/arch/x86/vdso
>   create mode 100644 tools/testing/selftests/vDSO/vgetrandom-chacha-finder.S

Jason,

I am seeing a few checkpatch warnings on this patch. They are
worth looking at.

WARNING: Prefer __weak over __attribute__((weak))
#176: FILE: tools/testing/selftests/vDSO/vdso_test_chacha.c:81:
+__attribute__((weak))

WARNING: Improper SPDX comment style for 'tools/testing/selftests/vDSO/vgetrandom-chacha-finder.S', please use '/*' instead
#191: FILE: tools/testing/selftests/vDSO/vgetrandom-chacha-finder.S:1:
+// SPDX-License-Identifier: GPL-2.0

WARNING: Missing or malformed SPDX-License-Identifier tag in line 1
#191: FILE: tools/testing/selftests/vDSO/vgetrandom-chacha-finder.S:1:
+// SPDX-License-Identifier: GPL-2.0


thanks,
-- Shuah

[PATCH kselftest v3 1/3] selftests: vDSO: unconditionally build chacha test

[Jason A. Donenfeld]

Rather than using symlinks to find the vgetrandom-chacha.S file for each
arch, store this in a file that uses the compiler to determine
architecture, and then make use of weak symbols to skip the test on
architectures that don't provide the code.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 tools/arch/arm64/vdso                          |  1 -
 tools/arch/loongarch/vdso                      |  1 -
 tools/arch/powerpc/vdso                        |  1 -
 tools/arch/s390/vdso                           |  1 -
 tools/arch/x86/vdso                            |  1 -
 tools/testing/selftests/vDSO/Makefile          |  6 +++---
 .../testing/selftests/vDSO/vdso_test_chacha.c  |  9 +++++----
 .../testing/selftests/vDSO/vgetrandom-chacha.S | 18 ++++++++++++++++++
 8 files changed, 26 insertions(+), 12 deletions(-)
 delete mode 120000 tools/arch/arm64/vdso
 delete mode 120000 tools/arch/loongarch/vdso
 delete mode 120000 tools/arch/powerpc/vdso
 delete mode 120000 tools/arch/s390/vdso
 delete mode 120000 tools/arch/x86/vdso
 create mode 100644 tools/testing/selftests/vDSO/vgetrandom-chacha.S

diff --git a/tools/arch/arm64/vdso b/tools/arch/arm64/vdso
deleted file mode 120000
index 233c7a26f6e5..000000000000
--- a/tools/arch/arm64/vdso
+++ /dev/null
@@ -1 +0,0 @@
-../../../arch/arm64/kernel/vdso
\ No newline at end of file
diff --git a/tools/arch/loongarch/vdso b/tools/arch/loongarch/vdso
deleted file mode 120000
index ebda43a82db7..000000000000
--- a/tools/arch/loongarch/vdso
+++ /dev/null
@@ -1 +0,0 @@
-../../../arch/loongarch/vdso
\ No newline at end of file
diff --git a/tools/arch/powerpc/vdso b/tools/arch/powerpc/vdso
deleted file mode 120000
index 4e676d1d1cb4..000000000000
--- a/tools/arch/powerpc/vdso
+++ /dev/null
@@ -1 +0,0 @@
-../../../arch/powerpc/kernel/vdso
\ No newline at end of file
diff --git a/tools/arch/s390/vdso b/tools/arch/s390/vdso
deleted file mode 120000
index 6cf4c1cebdcd..000000000000
--- a/tools/arch/s390/vdso
+++ /dev/null
@@ -1 +0,0 @@
-../../../arch/s390/kernel/vdso64
\ No newline at end of file
diff --git a/tools/arch/x86/vdso b/tools/arch/x86/vdso
deleted file mode 120000
index 7eb962fd3454..000000000000
--- a/tools/arch/x86/vdso
+++ /dev/null
@@ -1 +0,0 @@
-../../../arch/x86/entry/vdso/
\ No newline at end of file
diff --git a/tools/testing/selftests/vDSO/Makefile b/tools/testing/selftests/vDSO/Makefile
index af9cedbf5357..45641386c662 100644
--- a/tools/testing/selftests/vDSO/Makefile
+++ b/tools/testing/selftests/vDSO/Makefile
@@ -11,8 +11,8 @@ endif
 TEST_GEN_PROGS += vdso_test_correctness
 ifeq ($(ARCH)$(CONFIG_X86_32),$(filter $(ARCH)$(CONFIG_X86_32),x86 x86_64 loongarch arm64 powerpc s390))
 TEST_GEN_PROGS += vdso_test_getrandom
-TEST_GEN_PROGS += vdso_test_chacha
 endif
+TEST_GEN_PROGS += vdso_test_chacha
 
 CFLAGS := -std=gnu99 -O2
 
@@ -37,9 +37,9 @@ $(OUTPUT)/vdso_test_getrandom: CFLAGS += -isystem $(top_srcdir)/tools/include \
                                          $(KHDR_INCLUDES) \
                                          -isystem $(top_srcdir)/include/uapi
 
-$(OUTPUT)/vdso_test_chacha: $(top_srcdir)/tools/arch/$(SRCARCH)/vdso/vgetrandom-chacha.S
+$(OUTPUT)/vdso_test_chacha: vgetrandom-chacha.S
 $(OUTPUT)/vdso_test_chacha: CFLAGS += -idirafter $(top_srcdir)/tools/include \
                                       -idirafter $(top_srcdir)/tools/include/generated \
                                       -idirafter $(top_srcdir)/arch/$(SRCARCH)/include \
                                       -idirafter $(top_srcdir)/include \
-                                      -D__ASSEMBLY__ -Wa,--noexecstack
+                                      -Wa,--noexecstack
diff --git a/tools/testing/selftests/vDSO/vdso_test_chacha.c b/tools/testing/selftests/vDSO/vdso_test_chacha.c
index b1ea532c5996..c66eb9df89bd 100644
--- a/tools/testing/selftests/vDSO/vdso_test_chacha.c
+++ b/tools/testing/selftests/vDSO/vdso_test_chacha.c
@@ -3,6 +3,7 @@
  * Copyright (C) 2022-2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
  */
 
+#include <linux/compiler.h>
 #include <tools/le_byteshift.h>
 #include <sys/random.h>
 #include <sys/auxv.h>
@@ -73,10 +74,10 @@ static void reference_chacha20_blocks(uint8_t *dst_bytes, const uint32_t *key, u
 	counter[1] = s[13];
 }
 
-typedef uint8_t u8;
-typedef uint32_t u32;
-typedef uint64_t u64;
-#include <vdso/getrandom.h>
+void __weak __arch_chacha20_blocks_nostack(uint8_t *dst_bytes, const uint32_t *key, uint32_t *counter, size_t nblocks)
+{
+	ksft_exit_skip("Not implemented on architecture\n");
+}
 
 int main(int argc, char *argv[])
 {
diff --git a/tools/testing/selftests/vDSO/vgetrandom-chacha.S b/tools/testing/selftests/vDSO/vgetrandom-chacha.S
new file mode 100644
index 000000000000..d6e09af7c0a9
--- /dev/null
+++ b/tools/testing/selftests/vDSO/vgetrandom-chacha.S
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+
+#define __ASSEMBLY__
+
+#if defined(__aarch64__)
+#include "../../../../arch/arm64/kernel/vdso/vgetrandom-chacha.S"
+#elif defined(__loongarch__)
+#include "../../../../arch/loongarch/vdso/vgetrandom-chacha.S"
+#elif defined(__powerpc__) || defined(__powerpc64__)
+#include "../../../../arch/powerpc/kernel/vdso/vgetrandom-chacha.S"
+#elif defined(__s390x__)
+#include "../../../../arch/s390/kernel/vdso64/vgetrandom-chacha.S"
+#elif defined(__x86_64__)
+#include "../../../../arch/x86/entry/vdso/vgetrandom-chacha.S"
+#endif
-- 
2.46.0

[PATCH kselftest v3 2/3] selftests: vDSO: unconditionally build getrandom test

[Jason A. Donenfeld]

Rather than building on supported archs, build on all archs, and then
use the presence of the symbol in the vDSO to either skip the test or
move forward with it.

Note that this means that this test no longer checks whether the symbol
was correctly added to the kernel. But hopefully this will be clear
enough to developers and we'll cross our fingers that symbols aren't
removed by accident and not caught after this change.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 tools/testing/selftests/vDSO/Makefile              | 2 --
 tools/testing/selftests/vDSO/vdso_test_getrandom.c | 2 +-
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/tools/testing/selftests/vDSO/Makefile b/tools/testing/selftests/vDSO/Makefile
index 45641386c662..1cf14a8da438 100644
--- a/tools/testing/selftests/vDSO/Makefile
+++ b/tools/testing/selftests/vDSO/Makefile
@@ -9,9 +9,7 @@ ifeq ($(ARCH),$(filter $(ARCH),x86 x86_64))
 TEST_GEN_PROGS += vdso_standalone_test_x86
 endif
 TEST_GEN_PROGS += vdso_test_correctness
-ifeq ($(ARCH)$(CONFIG_X86_32),$(filter $(ARCH)$(CONFIG_X86_32),x86 x86_64 loongarch arm64 powerpc s390))
 TEST_GEN_PROGS += vdso_test_getrandom
-endif
 TEST_GEN_PROGS += vdso_test_chacha
 
 CFLAGS := -std=gnu99 -O2
diff --git a/tools/testing/selftests/vDSO/vdso_test_getrandom.c b/tools/testing/selftests/vDSO/vdso_test_getrandom.c
index 72a1d9b43a84..5489a2f07434 100644
--- a/tools/testing/selftests/vDSO/vdso_test_getrandom.c
+++ b/tools/testing/selftests/vDSO/vdso_test_getrandom.c
@@ -119,7 +119,7 @@ static void vgetrandom_init(void)
 	vgrnd.fn = (__typeof__(vgrnd.fn))vdso_sym(version, name);
 	if (!vgrnd.fn) {
 		printf("%s is missing!\n", name);
-		exit(KSFT_FAIL);
+		exit(KSFT_SKIP);
 	}
 	ret = VDSO_CALL(vgrnd.fn, 5, NULL, 0, 0, &vgrnd.params, ~0UL);
 	if (ret == -ENOSYS) {
-- 
2.46.0

[PATCH kselftest v3 3/3] selftests: vDSO: improve getrandom and chacha error messages

[Jason A. Donenfeld]

Improve the error and skip condition messages to let the developer know
precisely where a test has failed. Also make better use of the ksft api
for this.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 .../testing/selftests/vDSO/vdso_test_chacha.c | 27 ++++---
 .../selftests/vDSO/vdso_test_getrandom.c      | 75 ++++++++-----------
 2 files changed, 49 insertions(+), 53 deletions(-)

diff --git a/tools/testing/selftests/vDSO/vdso_test_chacha.c b/tools/testing/selftests/vDSO/vdso_test_chacha.c
index c66eb9df89bd..8757f738b0b1 100644
--- a/tools/testing/selftests/vDSO/vdso_test_chacha.c
+++ b/tools/testing/selftests/vDSO/vdso_test_chacha.c
@@ -91,10 +91,8 @@ int main(int argc, char *argv[])
 	ksft_set_plan(1);
 
 	for (unsigned int trial = 0; trial < TRIALS; ++trial) {
-		if (getrandom(key, sizeof(key), 0) != sizeof(key)) {
-			printf("getrandom() failed!\n");
-			return KSFT_SKIP;
-		}
+		if (getrandom(key, sizeof(key), 0) != sizeof(key))
+			ksft_exit_skip("getrandom() failed unexpectedly\n");
 		memset(counter1, 0, sizeof(counter1));
 		reference_chacha20_blocks(output1, key, counter1, BLOCKS);
 		for (unsigned int split = 0; split < BLOCKS; ++split) {
@@ -103,8 +101,10 @@ int main(int argc, char *argv[])
 			if (split)
 				__arch_chacha20_blocks_nostack(output2, key, counter2, split);
 			__arch_chacha20_blocks_nostack(output2 + split * BLOCK_SIZE, key, counter2, BLOCKS - split);
-			if (memcmp(output1, output2, sizeof(output1)) || memcmp(counter1, counter2, sizeof(counter1)))
-				return KSFT_FAIL;
+			if (memcmp(output1, output2, sizeof(output1)))
+				ksft_exit_fail_msg("Main loop outputs do not match on trial %u, split %u\n", trial, split);
+			if (memcmp(counter1, counter2, sizeof(counter1)))
+				ksft_exit_fail_msg("Main loop counters do not match on trial %u, split %u\n", trial, split);
 		}
 	}
 	memset(counter1, 0, sizeof(counter1));
@@ -114,14 +114,19 @@ int main(int argc, char *argv[])
 
 	reference_chacha20_blocks(output1, key, counter1, BLOCKS);
 	__arch_chacha20_blocks_nostack(output2, key, counter2, BLOCKS);
-	if (memcmp(output1, output2, sizeof(output1)) || memcmp(counter1, counter2, sizeof(counter1)))
-		return KSFT_FAIL;
+	if (memcmp(output1, output2, sizeof(output1)))
+		ksft_exit_fail_msg("Block limit outputs do not match after first round\n");
+	if (memcmp(counter1, counter2, sizeof(counter1)))
+		ksft_exit_fail_msg("Block limit counters do not match after first round\n");
 
 	reference_chacha20_blocks(output1, key, counter1, BLOCKS);
 	__arch_chacha20_blocks_nostack(output2, key, counter2, BLOCKS);
-	if (memcmp(output1, output2, sizeof(output1)) || memcmp(counter1, counter2, sizeof(counter1)))
-		return KSFT_FAIL;
+	if (memcmp(output1, output2, sizeof(output1)))
+		ksft_exit_fail_msg("Block limit outputs do not match after second round\n");
+	if (memcmp(counter1, counter2, sizeof(counter1)))
+		ksft_exit_fail_msg("Block limit counters do not match after second round\n");
 
 	ksft_test_result_pass("chacha: PASS\n");
-	return KSFT_PASS;
+	ksft_exit_pass();
+	return 0;
 }
diff --git a/tools/testing/selftests/vDSO/vdso_test_getrandom.c b/tools/testing/selftests/vDSO/vdso_test_getrandom.c
index 5489a2f07434..50ec9ad4c7ec 100644
--- a/tools/testing/selftests/vDSO/vdso_test_getrandom.c
+++ b/tools/testing/selftests/vDSO/vdso_test_getrandom.c
@@ -40,6 +40,9 @@
 	} while (0)
 #endif
 
+#define ksft_assert(condition) \
+	do { if (!(condition)) ksft_exit_fail_msg("Assertion failed: %s\n", #condition); } while (0)
+
 static struct {
 	pthread_mutex_t lock;
 	void **states;
@@ -109,26 +112,19 @@ static void vgetrandom_init(void)
 	const char *version = versions[VDSO_VERSION];
 	const char *name = names[VDSO_NAMES][6];
 	unsigned long sysinfo_ehdr = getauxval(AT_SYSINFO_EHDR);
-	size_t ret;
+	ssize_t ret;
 
-	if (!sysinfo_ehdr) {
-		printf("AT_SYSINFO_EHDR is not present!\n");
-		exit(KSFT_SKIP);
-	}
+	if (!sysinfo_ehdr)
+		ksft_exit_skip("AT_SYSINFO_EHDR is not present\n");
 	vdso_init_from_sysinfo_ehdr(sysinfo_ehdr);
 	vgrnd.fn = (__typeof__(vgrnd.fn))vdso_sym(version, name);
-	if (!vgrnd.fn) {
-		printf("%s is missing!\n", name);
-		exit(KSFT_SKIP);
-	}
+	if (!vgrnd.fn)
+		ksft_exit_skip("%s@%s symbol is missing from vDSO\n", name, version);
 	ret = VDSO_CALL(vgrnd.fn, 5, NULL, 0, 0, &vgrnd.params, ~0UL);
-	if (ret == -ENOSYS) {
-		printf("unsupported architecture\n");
-		exit(KSFT_SKIP);
-	} else if (ret) {
-		printf("failed to fetch vgetrandom params!\n");
-		exit(KSFT_FAIL);
-	}
+	if (ret == -ENOSYS)
+		ksft_exit_skip("CPU does not have runtime support\n");
+	else if (ret)
+		ksft_exit_fail_msg("Failed to fetch vgetrandom params: %zd\n", ret);
 }
 
 static ssize_t vgetrandom(void *buf, size_t len, unsigned long flags)
@@ -137,10 +133,7 @@ static ssize_t vgetrandom(void *buf, size_t len, unsigned long flags)
 
 	if (!state) {
 		state = vgetrandom_get_state();
-		if (!state) {
-			printf("vgetrandom_get_state failed!\n");
-			exit(KSFT_FAIL);
-		}
+		ksft_assert(state);
 	}
 	return VDSO_CALL(vgrnd.fn, 5, buf, len, flags, state, vgrnd.params.size_of_opaque_state);
 }
@@ -152,7 +145,7 @@ static void *test_vdso_getrandom(void *ctx)
 	for (size_t i = 0; i < TRIALS; ++i) {
 		unsigned int val;
 		ssize_t ret = vgetrandom(&val, sizeof(val), 0);
-		assert(ret == sizeof(val));
+		ksft_assert(ret == sizeof(val));
 	}
 	return NULL;
 }
@@ -162,7 +155,7 @@ static void *test_libc_getrandom(void *ctx)
 	for (size_t i = 0; i < TRIALS; ++i) {
 		unsigned int val;
 		ssize_t ret = getrandom(&val, sizeof(val), 0);
-		assert(ret == sizeof(val));
+		ksft_assert(ret == sizeof(val));
 	}
 	return NULL;
 }
@@ -172,7 +165,7 @@ static void *test_syscall_getrandom(void *ctx)
 	for (size_t i = 0; i < TRIALS; ++i) {
 		unsigned int val;
 		ssize_t ret = syscall(__NR_getrandom, &val, sizeof(val), 0);
-		assert(ret == sizeof(val));
+		ksft_assert(ret == sizeof(val));
 	}
 	return NULL;
 }
@@ -207,7 +200,7 @@ static void bench_multi(void)
 
 	clock_gettime(CLOCK_MONOTONIC, &start);
 	for (size_t i = 0; i < THREADS; ++i)
-		assert(pthread_create(&threads[i], NULL, test_vdso_getrandom, NULL) == 0);
+		ksft_assert(pthread_create(&threads[i], NULL, test_vdso_getrandom, NULL) == 0);
 	for (size_t i = 0; i < THREADS; ++i)
 		pthread_join(threads[i], NULL);
 	clock_gettime(CLOCK_MONOTONIC, &end);
@@ -216,7 +209,7 @@ static void bench_multi(void)
 
 	clock_gettime(CLOCK_MONOTONIC, &start);
 	for (size_t i = 0; i < THREADS; ++i)
-		assert(pthread_create(&threads[i], NULL, test_libc_getrandom, NULL) == 0);
+		ksft_assert(pthread_create(&threads[i], NULL, test_libc_getrandom, NULL) == 0);
 	for (size_t i = 0; i < THREADS; ++i)
 		pthread_join(threads[i], NULL);
 	clock_gettime(CLOCK_MONOTONIC, &end);
@@ -225,7 +218,7 @@ static void bench_multi(void)
 
 	clock_gettime(CLOCK_MONOTONIC, &start);
 	for (size_t i = 0; i < THREADS; ++i)
-		assert(pthread_create(&threads[i], NULL, test_syscall_getrandom, NULL) == 0);
+		ksft_assert(pthread_create(&threads[i], NULL, test_syscall_getrandom, NULL) == 0);
 	for (size_t i = 0; i < THREADS; ++i)
 		pthread_join(threads[i], NULL);
 	clock_gettime(CLOCK_MONOTONIC, &end);
@@ -250,48 +243,46 @@ static void kselftest(void)
 
 	for (size_t i = 0; i < 1000; ++i) {
 		ssize_t ret = vgetrandom(weird_size, sizeof(weird_size), 0);
-		if (ret != sizeof(weird_size))
-			exit(KSFT_FAIL);
+		ksft_assert(ret == sizeof(weird_size));
 	}
 
 	ksft_test_result_pass("getrandom: PASS\n");
 
 	unshare(CLONE_NEWUSER);
-	assert(unshare(CLONE_NEWTIME) == 0);
+	ksft_assert(unshare(CLONE_NEWTIME) == 0);
 	child = fork();
-	assert(child >= 0);
+	ksft_assert(child >= 0);
 	if (!child) {
 		vgetrandom_init();
 		child = getpid();
-		assert(ptrace(PTRACE_TRACEME, 0, NULL, NULL) == 0);
-		assert(kill(child, SIGSTOP) == 0);
-		assert(vgetrandom(weird_size, sizeof(weird_size), 0) == sizeof(weird_size));
+		ksft_assert(ptrace(PTRACE_TRACEME, 0, NULL, NULL) == 0);
+		ksft_assert(kill(child, SIGSTOP) == 0);
+		ksft_assert(vgetrandom(weird_size, sizeof(weird_size), 0) == sizeof(weird_size));
 		_exit(0);
 	}
 	for (;;) {
 		struct ptrace_syscall_info info = { 0 };
 		int status, ret;
-		assert(waitpid(child, &status, 0) >= 0);
+		ksft_assert(waitpid(child, &status, 0) >= 0);
 		if (WIFEXITED(status)) {
-			if (WEXITSTATUS(status) != 0)
-				exit(KSFT_FAIL);
+			ksft_assert(WEXITSTATUS(status) == 0);
 			break;
 		}
-		assert(WIFSTOPPED(status));
+		ksft_assert(WIFSTOPPED(status));
 		if (WSTOPSIG(status) == SIGSTOP)
-			assert(ptrace(PTRACE_SETOPTIONS, child, 0, PTRACE_O_TRACESYSGOOD) == 0);
+			ksft_assert(ptrace(PTRACE_SETOPTIONS, child, 0, PTRACE_O_TRACESYSGOOD) == 0);
 		else if (WSTOPSIG(status) == (SIGTRAP | 0x80)) {
-			assert(ptrace(PTRACE_GET_SYSCALL_INFO, child, sizeof(info), &info) > 0);
+			ksft_assert(ptrace(PTRACE_GET_SYSCALL_INFO, child, sizeof(info), &info) > 0);
 			if (info.op == PTRACE_SYSCALL_INFO_ENTRY && info.entry.nr == __NR_getrandom &&
 			    info.entry.args[0] == (uintptr_t)weird_size && info.entry.args[1] == sizeof(weird_size))
-				exit(KSFT_FAIL);
+				ksft_exit_fail_msg("vgetrandom passed buffer to syscall getrandom unexpectedly\n");
 		}
-		assert(ptrace(PTRACE_SYSCALL, child, 0, 0) == 0);
+		ksft_assert(ptrace(PTRACE_SYSCALL, child, 0, 0) == 0);
 	}
 
 	ksft_test_result_pass("getrandom timens: PASS\n");
 
-	exit(KSFT_PASS);
+	ksft_exit_pass();
 }
 
 static void usage(const char *argv0)
-- 
2.46.0

Re: [PATCH kselftest v3 1/3] selftests: vDSO: unconditionally build chacha test

[Shuah Khan]

On 10/7/24 15:45, Jason A. Donenfeld wrote:
> Rather than using symlinks to find the vgetrandom-chacha.S file for each
> arch, store this in a file that uses the compiler to determine
> architecture, and then make use of weak symbols to skip the test on
> architectures that don't provide the code.
> 
> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
> ---

Thank you.

Applied all three patches to linux-kselftest fixes and will
include them in my next pull request for rc3.

thanks,
-- Shuah

[PATCH kselftest 4/3] selftests: vDSO: unconditionally build chacha test

[Jason A. Donenfeld]

Rather than using symlinks to find the vgetrandom-chacha.S file for each
arch, store this in a file that uses the compiler to determine
architecture, and then make use of weak symbols to skip the test on
architectures that don't provide the code.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 tools/arch/arm64/vdso                            |  1 -
 tools/arch/loongarch/vdso                        |  1 -
 tools/arch/powerpc/vdso                          |  1 -
 tools/arch/s390/vdso                             |  1 -
 tools/arch/x86/vdso                              |  1 -
 tools/testing/selftests/vDSO/Makefile            |  6 +-----
 tools/testing/selftests/vDSO/vdso_test_chacha.c  |  6 ++++++
 .../selftests/vDSO/vgetrandom-chacha-finder.S    | 16 ++++++++++++++++
 8 files changed, 23 insertions(+), 10 deletions(-)
 delete mode 120000 tools/arch/arm64/vdso
 delete mode 120000 tools/arch/loongarch/vdso
 delete mode 120000 tools/arch/powerpc/vdso
 delete mode 120000 tools/arch/s390/vdso
 delete mode 120000 tools/arch/x86/vdso
 create mode 100644 tools/testing/selftests/vDSO/vgetrandom-chacha-finder.S

diff --git a/tools/arch/arm64/vdso b/tools/arch/arm64/vdso
deleted file mode 120000
index 233c7a26f6e5..000000000000
--- a/tools/arch/arm64/vdso
+++ /dev/null
@@ -1 +0,0 @@
-../../../arch/arm64/kernel/vdso
\ No newline at end of file
diff --git a/tools/arch/loongarch/vdso b/tools/arch/loongarch/vdso
deleted file mode 120000
index ebda43a82db7..000000000000
--- a/tools/arch/loongarch/vdso
+++ /dev/null
@@ -1 +0,0 @@
-../../../arch/loongarch/vdso
\ No newline at end of file
diff --git a/tools/arch/powerpc/vdso b/tools/arch/powerpc/vdso
deleted file mode 120000
index 4e676d1d1cb4..000000000000
--- a/tools/arch/powerpc/vdso
+++ /dev/null
@@ -1 +0,0 @@
-../../../arch/powerpc/kernel/vdso
\ No newline at end of file
diff --git a/tools/arch/s390/vdso b/tools/arch/s390/vdso
deleted file mode 120000
index 6cf4c1cebdcd..000000000000
--- a/tools/arch/s390/vdso
+++ /dev/null
@@ -1 +0,0 @@
-../../../arch/s390/kernel/vdso64
\ No newline at end of file
diff --git a/tools/arch/x86/vdso b/tools/arch/x86/vdso
deleted file mode 120000
index 7eb962fd3454..000000000000
--- a/tools/arch/x86/vdso
+++ /dev/null
@@ -1 +0,0 @@
-../../../arch/x86/entry/vdso/
\ No newline at end of file
diff --git a/tools/testing/selftests/vDSO/Makefile b/tools/testing/selftests/vDSO/Makefile
index 96b4f2a766e2..e453c178d97f 100644
--- a/tools/testing/selftests/vDSO/Makefile
+++ b/tools/testing/selftests/vDSO/Makefile
@@ -1,6 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
 include ../../../scripts/Makefile.arch
-top_srcdir = $(realpath ../../../..)
 
 TEST_GEN_PROGS := vdso_test_gettimeofday
 TEST_GEN_PROGS += vdso_test_getcpu
@@ -11,15 +10,12 @@ TEST_GEN_PROGS += vdso_standalone_test_x86
 endif
 TEST_GEN_PROGS += vdso_test_correctness
 TEST_GEN_PROGS += vdso_test_getrandom
-ifneq ($(wildcard $(top_srcdir)/tools/arch/$(SRCARCH)/vdso/vgetrandom-chacha.S),)
 TEST_GEN_PROGS += vdso_test_chacha
-endif
 
 CFLAGS := -std=gnu99 -O2
 
 ifeq ($(CONFIG_X86_32),y)
 LDLIBS += -lgcc_s
-TEST_GEN_PROGS := $(filter-out vdso_test_chacha,$(TEST_GEN_PROGS))
 endif
 
 include ../lib.mk
@@ -39,7 +35,7 @@ $(OUTPUT)/vdso_test_getrandom: CFLAGS += -isystem $(top_srcdir)/tools/include \
                                          $(KHDR_INCLUDES) \
                                          -isystem $(top_srcdir)/include/uapi
 
-$(OUTPUT)/vdso_test_chacha: $(top_srcdir)/tools/arch/$(SRCARCH)/vdso/vgetrandom-chacha.S
+$(OUTPUT)/vdso_test_chacha: vgetrandom-chacha-finder.S
 $(OUTPUT)/vdso_test_chacha: CFLAGS += -idirafter $(top_srcdir)/tools/include \
                                       -idirafter $(top_srcdir)/tools/include/generated \
                                       -idirafter $(top_srcdir)/arch/$(SRCARCH)/include \
diff --git a/tools/testing/selftests/vDSO/vdso_test_chacha.c b/tools/testing/selftests/vDSO/vdso_test_chacha.c
index 60c5ea5cb925..e68f1cd4ebcf 100644
--- a/tools/testing/selftests/vDSO/vdso_test_chacha.c
+++ b/tools/testing/selftests/vDSO/vdso_test_chacha.c
@@ -78,6 +78,12 @@ typedef uint32_t u32;
 typedef uint64_t u64;
 #include <vdso/getrandom.h>
 
+__attribute__((weak))
+void __arch_chacha20_blocks_nostack(u8 *dst_bytes, const u32 *key, u32 *counter, size_t nblocks)
+{
+	ksft_exit_skip("Not implemented on architecture\n");
+}
+
 int main(int argc, char *argv[])
 {
 	enum { TRIALS = 1000, BLOCKS = 128, BLOCK_SIZE = 64 };
diff --git a/tools/testing/selftests/vDSO/vgetrandom-chacha-finder.S b/tools/testing/selftests/vDSO/vgetrandom-chacha-finder.S
new file mode 100644
index 000000000000..1ca240ddaab7
--- /dev/null
+++ b/tools/testing/selftests/vDSO/vgetrandom-chacha-finder.S
@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+
+#if defined(__aarch64__)
+#include "../../../../arch/arm64/kernel/vdso/vgetrandom-chacha.S"
+#elif defined(__loongarch__)
+#include "../../../../arch/loongarch/vdso/vgetrandom-chacha.S"
+#elif defined(__powerpc__) || defined(__powerpc64__)
+#include "../../../../arch/powerpc/kernel/vdso/vgetrandom-chacha.S"
+#elif defined(__s390x__)
+#include "../../../../arch/s390/kernel/vdso64/vgetrandom-chacha.S"
+#elif defined(__x86_64__)
+#include "../../../../arch/x86/entry/vdso/vgetrandom-chacha.S"
+#endif
-- 
2.46.0

Re: [PATCH kselftest 0/3] getrandom & chacha cleanups

[Shuah Khan]

On 10/2/24 21:13, Jason A. Donenfeld wrote:
> Hi Shuah,
> 
> I've now read your email several times trying to figure out what you
> meant and what your objections are. This series is my best attempt at
> trying to satisfy that. But my understanding still has a lot of question
> marks, so I may have missed your point here. Nonetheless, maybe this
> moves things forward a bit.
> 
> Jason
> 
> Cc: Shuah Khan <skhan@linuxfoundation.org>
> Cc: Greg KH <greg@kroah.com>
> 
> Jason A. Donenfeld (3):
>    selftests: vDSO: condition chacha build on chacha implementation
>    selftests: vDSO: unconditionally build getrandom test
>    selftests: vDSO: improve getrandom and chacha error messages
> 
>   tools/testing/selftests/vDSO/Makefile         |  4 +-
>   .../testing/selftests/vDSO/vdso_test_chacha.c | 27 ++++---
>   .../selftests/vDSO/vdso_test_getrandom.c      | 75 ++++++++-----------
>   3 files changed, 52 insertions(+), 54 deletions(-)
> 

Thank you Jason for fixing the problem. The patches look good
to me. I will run some tests and apply all 4 patches for next rc.

I did review the 4th patch as well.
https://patchwork.kernel.org/project/linux-kselftest/patch/20241003171852.2386463-1-Jason@zx2c4.com/

than

Re: Patch "selftests: vDSO: skip getrandom test if architecture is unsupported" has been added to the 6.11-stable tree

[Shuah Khan]

On 10/2/24 15:01, Jason A. Donenfeld wrote:
> On Wed, Oct 02, 2024 at 01:45:57PM -0600, Shuah Khan wrote:
>> This is not different from other kernel APIs and enhancements and
>> correspo0nding updates to the existing selftests.
>>
>> The
>> vdso_test_getrandom test a user-space program exists in 6.11.
>>
>> Use should be able to run vdso_test_getrandom compiled on 6.12
>> repo on a 6.11 kernel.
>> vdso_test_getrandom test a user-space program exists in 6.11.
>> Users should be able to run vdso_test_getrandom compiled on 6.12
>> repo on a 6.11 kernel. This is what several CIs do.
> 
> The x86 test from 6.12 works just fine on 6.11.

Yes x86 test is a good example to look at that handles 32-bit
and 640-bit issues you brought up in your email.

That is reason why I asked you to refer to x86 Makefile to
solve the architecture differences related to this test you
mentioned in your email.

> 
> I really don't follow you at all or what you're getting at. I think if
> you actually look at the code, you'll be mostly okay with it. And if
> there's something that looks awry to you, send a patch or describe to me
> clearly what looks wrong and I'll send a patch.
To be very clear about the selftest guidelines (covered in
kselftest.rst document)

1. Ideally selftests should compile on all architectures.
    Exception to this are few architecture specific
    features which can be selectively compiled either
    with ifdef statements in the code or Makefile arch
    checks.
    
    The goal is to keep these to a minimum so we can a wide
    range of tests in CIs and other test systems.

2. Selftest from mainline should run on stable releases
    handling missing features and missing config options
    with skip so we don't have to deal false failures.

    The goal is to minimize false negatives and false positives.

3. Reported results are clear to the users and testers.

Thank you for the patches. I will review your patches and give you
feedback.

thanks,
-- Shuah

Re: Patch "selftests: vDSO: skip getrandom test if architecture is unsupported" has been added to the 6.11-stable tree

[Jason A. Donenfeld]

On Thu, Oct 3, 2024 at 6:53 PM Shuah Khan <skhan@linuxfoundation.org> wrote:
> > The x86 test from 6.12 works just fine on 6.11.
>
> Yes x86 test is a good example to look at that handles 32-bit
> and 640-bit issues you brought up in your email.

The x86 test is only for 64-bit. It doesn't get compiled on 32-bit.
That changes in the series I attached.

> 1. Ideally selftests should compile on all architectures.
>     Exception to this are few architecture specific
>     features which can be selectively compiled either
>     with ifdef statements in the code or Makefile arch
>     checks.

The thing is, this *is* a test with an architecture-specific feature:
it's not available on all archs, especially not 32-bit ones. There's
the workaround (in the attached series) that I think might help
things. But for the chacha one, it just won't compile on systems that
lack the implementation.

> 2. Selftest from mainline should run on stable releases
>     handling missing features and missing config options
>     with skip so we don't have to deal false failures.

Noted. I would like to point out, though, that this is the "opposite"
stability guarantee that Linux usually offers of old binaries working
on new systems. You want new binaries working on old systems.

> 3. Reported results are clear to the users and testers.

Patch 3/3 fixes this up.

> Thank you for the patches. I will review your patches and give you
> feedback.

Great, okay. I think the series matches your expectations.

I have additional ideas too for the chacha test, if you think it's
necessary to go further, but maybe things are good enough now.

Jason

Re: Patch "selftests: vDSO: skip getrandom test if architecture is unsupported" has been added to the 6.11-stable tree

[Jason A. Donenfeld]

On Thu, Oct 03, 2024 at 06:58:26PM +0200, Jason A. Donenfeld wrote:
> Great, okay. I think the series matches your expectations.
> 
> I have additional ideas too for the chacha test, if you think it's
> necessary to go further, but maybe things are good enough now.

Posted patch 4/3 for this purpose:
    https://lore.kernel.org/all/20241003171852.2386463-1-Jason@zx2c4.com/