linux-kernel - Re: [PATCH v3] lib/test_string.c: Add strncmp() tests

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Message-ID: <CAHp75Vej41uWK9hUOuU=p2D3BwgznhjBzSLbFgRcdY8_X=brpQ@mail.gmail.com>
Date:   Thu, 2 Mar 2023 12:26:21 +0200
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Björn Töpel <bjorn@...nel.org>
Cc:     Palmer Dabbelt <palmer@...belt.com>,
        Andy Shevchenko <andy@...nel.org>,
        linux-kernel@...r.kernel.org, Palmer Dabbelt <palmer@...osinc.com>,
        Heiko Stuebner <heiko@...ech.de>,
        linux-riscv@...ts.infradead.org,
        Björn Töpel <bjorn@...osinc.com>
Subject: Re: [PATCH v3] lib/test_string.c: Add strncmp() tests

On Thu, Mar 2, 2023 at 9:19 AM Björn Töpel <bjorn@...nel.org> wrote:
>
> From: Palmer Dabbelt <palmer@...osinc.com>
>
> The RISC-V strncmp() fails on some inputs, see the linked thread for
> more details. It turns out there were no strncmp() calls in the self
> tests, this adds one.

Thank you, it's good enough.

Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>

> Reported-by: Heiko Stübner <heiko@...ech.de>
> Link: https://lore.kernel.org/all/2801162.88bMQJbFj6@diego/
> Signed-off-by: Palmer Dabbelt <palmer@...osinc.com>
> Signed-off-by: Björn Töpel <bjorn@...osinc.com>
> ---
> Change back to it's original form. Checkpatch still complains about
> __initconst, but there's a patch addressing that [1].
>
> [1] https://lore.kernel.org/all/20230301094320.15954-1-bjorn@kernel.org/
>
> v2->v3: Removed the "checkpatch fix" patch
>         Added one more test
>
> v1->v2: Added two more tests (pos/neg). (Andy)
>         Minor code style issues. (Andy)
>         Fixed checkpatch errors.
> ---
> lib/test_string.c | 42 ++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 42 insertions(+)
>
> diff --git a/lib/test_string.c b/lib/test_string.c
> index c5cb92fb710e..f18a34578f1f 100644
> --- a/lib/test_string.c
> +++ b/lib/test_string.c
> @@ -207,6 +207,43 @@ static __init int strspn_selftest(void)
>         return 0;
>  }
>
> +static __init int strncmp_selftest(void)
> +{
> +       size_t i;
> +       static const struct strncmp_test {
> +               const char *str_a;
> +               const char *str_b;
> +               unsigned long count;
> +               unsigned long max_off;
> +               int retval;
> +       } tests[] __initconst = {
> +               { "/dev/vda", "/dev/", 5, 4, 0 },
> +               { "/dev/vda", "/dev/vdb", 5, 4, 0 },
> +               { "00000000---11111", "00000000---11112", 12, 4, 0 },
> +               { "/dev/vda", "/dev/vd\0", 8, 0, 97 },
> +               { "ABC", "AB", 3, 0, 67 },
> +               { "ABA", "ABZ", 3, 0, -25 },
> +               { "ABC", "ABC", 3, 0, 0 },
> +       };
> +
> +       for (i = 0; i < ARRAY_SIZE(tests); ++i) {
> +               const struct strncmp_test *s = tests + i;
> +               size_t off;
> +
> +               for (off = 0; off <= s->max_off; off++) {
> +                       int res = strncmp(s->str_a + off, s->str_b + off, s->count - off);
> +
> +                       if (res == 0 && s->retval != 0)
> +                               return 0x1000 + 0x100*off + 0x10*i + 0x0;
> +                       if (res > 0 && s->retval <= 0)
> +                               return 0x1000 + 0x100*off + 0x10*i + 0x1;
> +                       if (res < 0 && s->retval >= 0)
> +                               return 0x1000 + 0x100*off + 0x10*i + 0x2;
> +               }
> +       }
> +       return 0;
> +}
> +
>  static __exit void string_selftest_remove(void)
>  {
>  }
> @@ -245,6 +282,11 @@ static __init int string_selftest_init(void)
>         if (subtest)
>                 goto fail;
>
> +       test = 7;
> +       subtest = strncmp_selftest();
> +       if (subtest)
> +               goto fail;
> +
>         pr_info("String selftests succeeded\n");
>         return 0;
>  fail:
>
> base-commit: c0927a7a5391f7d8e593e5e50ead7505a23cadf9
> --
> 2.37.2
>


-- 
With Best Regards,
Andy Shevchenko