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From: Lucas De Marchi <lucas.demarchi@intel.com>
To: Yury Norov <yury.norov@gmail.com>
Cc: linux-kernel@vger.kernel.org,
	dri-devel@lists.freedesktop.org,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Jani Nikula <jani.nikula@linux.intel.com>,
	intel-xe@lists.freedesktop.org,
	intel-gfx@lists.freedesktop.org,
	Lucas De Marchi <lucas.demarchi@intel.com>
Subject: [PATCH 2/3] bits: Introduce fixed-type BIT
Date: Tue, 23 Jan 2024 21:02:04 -0800
Message-ID: <20240124050205.3646390-3-lucas.demarchi@intel.com>
In-Reply-To: <20240124050205.3646390-1-lucas.demarchi@intel.com>
References: <20240124050205.3646390-1-lucas.demarchi@intel.com>
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Implement fixed-type BIT() to help drivers add stricter checks, like was
done for GENMASK.

Signed-off-by: Lucas De Marchi <lucas.demarchi@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