[PATCH 2/3] bits: Introduce fixed-type BIT
Lucas De Marchi
lucas.demarchi at intel.com
Wed Jan 24 05:02:04 UTC 2024
Implement fixed-type BIT() to help drivers add stricter checks, like was
done for GENMASK.
Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>
---
include/linux/bits.h | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/include/linux/bits.h b/include/linux/bits.h
index cb94128171b2..5754a1251078 100644
--- a/include/linux/bits.h
+++ b/include/linux/bits.h
@@ -24,12 +24,16 @@
#define GENMASK_INPUT_CHECK(h, l) \
(BUILD_BUG_ON_ZERO(__builtin_choose_expr( \
__is_constexpr((l) > (h)), (l) > (h), 0)))
+#define BIT_INPUT_CHECK(type, b) \
+ ((BUILD_BUG_ON_ZERO(__builtin_choose_expr( \
+ __is_constexpr(b), (b) >= BITS_PER_TYPE(type), 0))))
#else
/*
* BUILD_BUG_ON_ZERO is not available in h files included from asm files,
* disable the input check if that is the case.
*/
#define GENMASK_INPUT_CHECK(h, l) 0
+#define BIT_INPUT_CHECK(type, b) 0
#endif
#define __GENMASK(t, h, l) \
@@ -44,4 +48,9 @@
#define GENMASK_U32(h, l) __GENMASK(u32, h, l)
#define GENMASK_U64(h, l) __GENMASK(u64, h, l)
+#define BIT_U8(b) ((u8)(BIT_INPUT_CHECK(u8, b) + BIT(b)))
+#define BIT_U16(b) ((u16)(BIT_INPUT_CHECK(u16, b) + BIT(b)))
+#define BIT_U32(b) ((u32)(BIT_INPUT_CHECK(u32, b) + BIT(b)))
+#define BIT_U64(b) ((u64)(BIT_INPUT_CHECK(u64, b) + BIT(b)))
+
#endif /* __LINUX_BITS_H */
--
2.43.0
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