On 23.08.2024 01:06, Andrew Cooper wrote:
> This will be used to simplify real logic in the following patch. Add compile
> and boot time testing as with other bitops.
>
> Because the expression is so simple, implement it as a function-like macro
> which is generic on the type of it's argument, rather than having multiple
> variants.
>
> Testing function-like macros needs a minor adjustments to the infrastructure
> in xen/self-tests.h to avoid bracketing the fn parameter. The utility of this
> outweighs the associated risks.
We may need to mark these two places as deviated.
> Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
Reviewed-by: Jan Beulich <jbeul...@suse.com>
with one remark/request:
> --- a/xen/common/bitops.c
> +++ b/xen/common/bitops.c
> @@ -84,8 +84,32 @@ static void __init test_fls(void)
> CHECK(fls64, 0x8000000000000001ULL, 64);
> }
>
> +static void __init test_multiple_bits_set(void)
> +{
> + /*
> + * multiple_bits_set() is generic on the type of it's parameter, as the
> + * internal expression is so simple.
> + */
> +
> + CHECK(multiple_bits_set, 0, false);
> + CHECK(multiple_bits_set, 1, false);
> + CHECK(multiple_bits_set, 2, false);
> + CHECK(multiple_bits_set, 3, true);
> +
> + CHECK(multiple_bits_set, 1 | (1UL << (BITS_PER_LONG - 1)), true);
This is really the same as ...
> +#if BITS_PER_LONG > 32
> + CHECK(multiple_bits_set, 1 | (1UL << 32), true);
> + CHECK(multiple_bits_set, 1 | (1UL << 63), true);
... this, at least as long as BITS_PER_LONG > 32 in practice means
BITS_PER_LONG == 64. Perhaps not really worth keeping that line?
Jan
