Re: [PATCH v5 1/7] bits: split the definition of the asm and non-asm GENMASK()

Lucas De Marchi
2025-03-06T14:34:36Z

On Thu, Mar 06, 2025 at 08:29:52PM +0900, Vincent Mailhol via B4 Relay wrote:
>From: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
>
>In an upcoming change, GENMASK() and its friends will indirectly
>depend on sizeof() which is not available in asm.
>
>Instead of adding further complexity to __GENMASK() to make it work
>for both asm and non asm, just split the definition of the two
>variants.
>
>Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
>---
>Changelog:
>
> v4 -> v5:
>
> - Use tab indentations instead of single space to separate the
> macro name from its body.
>
> v3 -> v4:
>
> - New patch in the series
>---
> include/linux/bits.h | 18 +++++++++---------
> 1 file changed, 9 insertions(+), 9 deletions(-)
>
>diff --git a/include/linux/bits.h b/include/linux/bits.h
>index 14fd0ca9a6cd17339dd2f69e449558312a8a001b..4819cbe7bd48fbae796fc6005c9f92b1c93a034c 100644
>--- a/include/linux/bits.h
>+++ b/include/linux/bits.h
>@@ -19,23 +19,17 @@
> * GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
> */
> #if !defined(__ASSEMBLY__)
>+
> #include <linux/build_bug.h>
> #include <linux/compiler.h>
>+
> #define GENMASK_INPUT_CHECK(h, l) BUILD_BUG_ON_ZERO(const_true((l) > (h)))
>-#else
>-/*
>- * BUILD_BUG_ON_ZERO is not available in h files included from asm files,
>- * disable the input check if that is the case.
>- */

it seems we now have 1 inconsistency that we comment why
GENMASK_U128() is not available in asm, but we don't comment why
GENMASK_INPUT_CHECK() is not available there. Maybe move this comment on
top of GENMASK_INPUT_CHECK().

Anyway,

Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>

thanks for picking up this series.

Lucas De Marchi

>-#define GENMASK_INPUT_CHECK(h, l) 0
>-#endif
>
> #define GENMASK(h, l) \
> (GENMASK_INPUT_CHECK(h, l) + __GENMASK(h, l))
> #define GENMASK_ULL(h, l) \
> (GENMASK_INPUT_CHECK(h, l) + __GENMASK_ULL(h, l))
>
>-#if !defined(__ASSEMBLY__)
> /*
> * Missing asm support
> *
>@@ -48,6 +42,12 @@
> */
> #define GENMASK_U128(h, l) \
> (GENMASK_INPUT_CHECK(h, l) + __GENMASK_U128(h, l))
>-#endif
>+
>+#else /* defined(__ASSEMBLY__) */
>+
>+#define GENMASK(h, l) __GENMASK(h, l)
>+#define GENMASK_ULL(h, l) __GENMASK_ULL(h, l)
>+
>+#endif /* !defined(__ASSEMBLY__) */
>
> #endif /* __LINUX_BITS_H */
>
>--
>2.45.3
>
>