kunit: Don't use a managed alloc in is_literal()

There is no need to use a test-managed alloc in is_literal().
The function frees the temporary buffer before returning.

This removes the only use of the test and gfp members of
struct string_stream outside of the string_stream implementation.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: fix bug in KUNIT_EXPECT_MEMEQ

In KUNIT_EXPECT_MEMEQ and KUNIT_EXPECT_MEMNEQ, add check if one of the
inputs is NULL and fail if this is the case.

Currently, the kernel crashes if one of the inputs is NULL. Instead,
fail the test and add an appropriate error message.

Fixes: b8a926bea8b1 ("kunit: Introduce KUNIT_EXPECT_MEMEQ and KUNIT_EXPECT_MEMNEQ macros")

This was found by the kernel test robot:
https://lore.kernel.org/all/202212191448.D6EDPdOh-lkp@intel.com/

Reported-by: kernel test robot <lkp@intel.com>

Signed-off-by: Rae Moar <rmoar@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: Introduce KUNIT_EXPECT_MEMEQ and KUNIT_EXPECT_MEMNEQ macros

Currently, in order to compare memory blocks in KUnit, the KUNIT_EXPECT_EQ
or KUNIT_EXPECT_FALSE macros are used in conjunction with the memcmp
function, such as:
KUNIT_EXPECT_EQ(test, memcmp(foo, bar, size), 0);

Although this usage produces correct results for the test cases, when
the expectation fails, the error message is not very helpful,
indicating only the return of the memcmp function.

Therefore, create a new set of macros KUNIT_EXPECT_MEMEQ and
KUNIT_EXPECT_MEMNEQ that compare memory blocks until a specified size.
In case of expectation failure, those macros print the hex dump of the
memory blocks, making it easier to debug test failures for memory blocks.

That said, the expectation

KUNIT_EXPECT_EQ(test, memcmp(foo, bar, size), 0);

would translate to the expectation

KUNIT_EXPECT_MEMEQ(test, foo, bar, size);

Signed-off-by: Maíra Canal <mairacanal@riseup.net>
Reviewed-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: log numbers in decimal and hex

When KUNIT_EXPECT_EQ() or KUNIT_ASSERT_EQ() log a failure, they log the
two values being compared, with numerical values logged in decimal.

In some cases, decimal output is painful to consume, and hexadecimal
output would be more helpful. For example, this is the case for tests
I'm currently developing for the arm64 insn encoding/decoding code,
where comparing two 32-bit instruction opcodes results in output such
as:

| # test_insn_add_shifted_reg: EXPECTATION FAILED at arch/arm64/lib/test_insn.c:2791
| Expected obj_insn == gen_insn, but
| obj_insn == 2332164128
| gen_insn == 1258422304

To make this easier to consume, this patch logs the values in both
decimal and hexadecimal:

| # test_insn_add_shifted_reg: EXPECTATION FAILED at arch/arm64/lib/test_insn.c:2791
| Expected obj_insn == gen_insn, but
| obj_insn == 2332164128 (0x8b020020)
| gen_insn == 1258422304 (0x4b020020)

As can be seen from the example, having hexadecimal makes it
significantly easier for a human to spot which specific bits are
incorrect.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: linux-kselftest@vger.kernel.org
Cc: kunit-dev@googlegroups.com
Acked-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: factor out str constants from binary assertion structs

If the compiler doesn't optimize them away, each kunit assertion (use of
KUNIT_EXPECT_EQ, etc.) can use 88 bytes of stack space in the worst and
most common case. This has led to compiler warnings and a suggestion
from Linus to move data from the structs into static const's where
possible [1].

This builds upon [2] which did so for the base struct kunit_assert type.
That only reduced sizeof(struct kunit_binary_assert) from 88 to 64.

Given these are by far the most commonly used asserts, this patch
factors out the textual representations of the operands and comparator
into another static const, saving 16 more bytes.

In detail, KUNIT_EXPECT_EQ(test, 2 + 2, 5) yields the following struct
(struct kunit_binary_assert) {
.assert = <struct kunit_assert>,
.operation = "==",
.left_text = "2 + 2",
.left_value = 4,
.right_text = "5",
.right_value = 5,
}
After this change
static const struct kunit_binary_assert_text __text = {
.operation = "==",
.left_text = "2 + 2",
.right_text = "5",
};
(struct kunit_binary_assert) {
.assert = <struct kunit_assert>,
.text = &__text,
.left_value = 4,
.right_value = 5,
}

This also DRYs the code a bit more since these str fields were repeated
for the string and pointer versions of kunit_binary_assert.

Note: we could name the kunit_binary_assert_text fields left/right
instead of left_text/right_text. But that would require changing the
macros a bit since they have args called "left" and "right" which would
be substituted in `.left = #left` as `.2 + 2 = \"2 + 2\"`.

[1] https://groups.google.com/g/kunit-dev/c/i3fZXgvBrfA/m/VULQg1z6BAAJ
[2] https://lore.kernel.org/linux-kselftest/20220113165931.451305-6-dlatypov@google.com/

Signed-off-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: remove va_format from kunit_assert

The concern is that having a lot of redundant fields in kunit_assert can
blow up stack usage if the compiler doesn't optimize them away [1].

The comment on this field implies that it was meant to be initialized
when the expect/assert was declared, but this only happens when we run
kunit_do_failed_assertion().

We don't need to access it outside of that function, so move it out of
the struct and make it a local variable there.

This change also takes the chance to reduce the number of macros by
inlining the now simplified KUNIT_INIT_ASSERT_STRUCT() macro.

[1] https://groups.google.com/g/kunit-dev/c/i3fZXgvBrfA/m/VULQg1z6BAAJ

Signed-off-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: split out part of kunit_assert into a static const

This is per Linus's suggestion in [1].

The issue there is that every KUNIT_EXPECT/KUNIT_ASSERT puts a
kunit_assert object onto the stack. Normally we rely on compilers to
elide this, but when that doesn't work out, this blows up the stack
usage of kunit test functions.

We can move some data off the stack by making it static.
This change introduces a new `struct kunit_loc` to hold the file and
line number and then just passing assert_type (EXPECT or ASSERT) as an
argument.

In [1], it was suggested to also move out the format string as well, but
users could theoretically craft a format string at runtime, so we can't.

This change leaves a copy of `assert_type` in kunit_assert for now
because cleaning up all the macros to not pass it around is a bit more
involved.

Here's an example of the expanded code for KUNIT_FAIL():
if (__builtin_expect(!!(!(false)), 0)) {
static const struct kunit_loc loc = { .file = ... };
struct kunit_fail_assert __assertion = { .assert = { .type ... };
kunit_do_failed_assertion(test, &loc, KUNIT_EXPECTATION, &__assertion.assert, ...);
};

[1] https://groups.google.com/g/kunit-dev/c/i3fZXgvBrfA/m/VULQg1z6BAAJ

Signed-off-by: Daniel Latypov <dlatypov@google.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: factor out kunit_base_assert_format() call into kunit_fail()

We call this function first thing for all the assertion `format()`
functions.
This is the part that prints the file and line number and assertion type
(EXPECTATION, ASSERTION).

Having it as part of the format functions lets us have the flexibility
to not print that information (or print it differently) for new
assertion types, but I think this we don't need that.

And in the future, we'd like to consider factoring that data (file,
line#, type) out of the kunit_assert struct and into a `static`
variable, as Linus suggested [1], so we'd need to extract it anyways.

[1] https://groups.google.com/g/kunit-dev/c/i3fZXgvBrfA/m/VULQg1z6BAAJ

Signed-off-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: make KUNIT_EXPECT_STREQ() quote values, don't print literals

Before:
> Expected str == "world", but
> str == hello
> "world" == world

After:
> Expected str == "world", but
> str == "hello"
<we don't need to tell the user that "world" == "world">

Note: like the literal ellision for integers, this doesn't handle the
case of
KUNIT_EXPECT_STREQ(test, "hello", "world")
since we don't expect it to realistically happen in checked in tests.
(If you really wanted a test to fail, KUNIT_FAIL("msg") exists)

In that case, you'd get:
> Expected "hello" == "world", but
<output for next failure>

Signed-off-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: Match parenthesis alignment to improve code readability

Tidy up code by fixing the following checkpatch warnings:
CHECK: Alignment should match open parenthesis
CHECK: Lines should not end with a '('

Signed-off-by: Lucas Stankus <lucas.p.stankus@gmail.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: don't show `1 == 1` in failed assertion messages

Currently, given something (fairly dystopian) like
> KUNIT_EXPECT_EQ(test, 2 + 2, 5)

KUnit will prints a failure message like this.
> Expected 2 + 2 == 5, but
> 2 + 2 == 4
> 5 == 5

With this patch, the output just becomes
> Expected 2 + 2 == 5, but
> 2 + 2 == 4

This patch is slightly hacky, but it's quite common* to compare an
expression to a literal integer value, so this can make KUnit less
chatty in many cases. (This patch also fixes variants like
KUNIT_EXPECT_GT, LE, et al.).

It also allocates an additional string briefly, but given this only
happens on test failures, it doesn't seem too bad a tradeoff.
Also, in most cases it'll realize the lengths are unequal and bail out
before the allocation.

We could save the result of the formatted string to avoid wasting this
extra work, but it felt cleaner to leave it as-is.

Edge case: for something silly and unrealistic like
> KUNIT_EXPECT_EQ(test, 4, 5);

It'll generate this message with a trailing "but"
> Expected 4 == 5, but
> <next line of normal output>

It didn't feel worth adding a check up-front to see if both sides are
literals to handle this better.

*A quick grep suggests 100+ comparisons to an integer literal as the
right hand side.

Signed-off-by: Daniel Latypov <dlatypov@google.com>
Tested-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: subtests should be indented 4 spaces according to TAP

Introduce KUNIT_SUBTEST_INDENT macro which corresponds to 4-space
indentation and KUNIT_SUBSUBTEST_INDENT macro which corresponds to
8-space indentation in line with TAP spec (e.g. see "Subtests"
section of https://node-tap.org/tap-protocol/).

Use these macros in place of one or two tabs in strings to clarify
why we are indenting.

Suggested-by: Frank Rowand <frowand.list@gmail.com>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Reviewed-by: Frank Rowand <frank.rowand@sony.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: Always print actual pointer values in asserts

KUnit assertions and expectations will print the values being tested. If
these are pointers (e.g., KUNIT_EXPECT_PTR_EQ(test, a, b)), these
pointers are currently printed with the %pK format specifier, which -- to
prevent information leaks which may compromise, e.g., ASLR -- are often
either hashed or replaced with ____ptrval____ or similar, making debugging
tests difficult.

By replacing %pK with %px as Documentation/core-api/printk-formats.rst
suggests, we disable this security feature for KUnit assertions and
expectations, allowing the actual pointer values to be printed. Given
that KUnit is not intended for use in production kernels, and the
pointers are only printed on failing tests, this seems like a worthwhile
tradeoff.

Signed-off-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: allow kunit tests to be loaded as a module

As tests are added to kunit, it will become less feasible to execute
all built tests together. By supporting modular tests we provide
a simple way to do selective execution on a running system; specifying

CONFIG_KUNIT=y
CONFIG_KUNIT_EXAMPLE_TEST=m

...means we can simply "insmod example-test.ko" to run the tests.

To achieve this we need to do the following:

o export the required symbols in kunit
o string-stream tests utilize non-exported symbols so for now we skip
building them when CONFIG_KUNIT_TEST=m.
o drivers/base/power/qos-test.c contains a few unexported interface
references, namely freq_qos_read_value() and freq_constraints_init().
Both of these could be potentially defined as static inline functions
in include/linux/pm_qos.h, but for now we simply avoid supporting
module build for that test suite.
o support a new way of declaring test suites. Because a module cannot
do multiple late_initcall()s, we provide a kunit_test_suites() macro
to declare multiple suites within the same module at once.
o some test module names would have been too general ("test-test"
and "example-test" for kunit tests, "inode-test" for ext4 tests);
rename these as appropriate ("kunit-test", "kunit-example-test"
and "ext4-inode-test" respectively).

Also define kunit_test_suite() via kunit_test_suites()
as callers in other trees may need the old definition.

Co-developed-by: Knut Omang <knut.omang@oracle.com>
Signed-off-by: Knut Omang <knut.omang@oracle.com>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Acked-by: Theodore Ts'o <tytso@mit.edu> # for ext4 bits
Acked-by: David Gow <davidgow@google.com> # For list-test
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: move string-stream.h to lib/kunit

string-stream interfaces are not intended for external use;
move them from include/kunit to lib/kunit accordingly.

Co-developed-by: Knut Omang <knut.omang@oracle.com>
Signed-off-by: Knut Omang <knut.omang@oracle.com>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Tested-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: test: add assertion printing library

Add `struct kunit_assert` and friends which provide a structured way to
capture data from an expectation or an assertion (introduced later in
the series) so that it may be printed out in the event of a failure.

Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>