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From: Yury Norov <ynorov@nvidia.com>
To: Paul Walmsley <pjw@kernel.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Alexandre Ghiti <alex@ghiti.fr>,
	Yury Norov <yury.norov@gmail.com>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Arnd Bergmann <arnd@arndb.de>,
	Andrew Lunn <andrew+netdev@lunn.ch>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Jesper Dangaard Brouer <hawk@kernel.org>,
	John Fastabend <john.fastabend@gmail.com>,
	Stanislav Fomichev <sdf@fomichev.me>,
	Jinjie Ruan <ruanjinjie@huawei.com>,
	linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
	linux-arch@vger.kernel.org, netdev@vger.kernel.org,
	bpf@vger.kernel.org
Cc: Yury Norov <ynorov@nvidia.com>
Subject: [PATCH 3/6] bitops: Define generic __bitrev8/16/32 for reuse
Date: Thu, 30 Apr 2026 17:13:47 -0400	[thread overview]
Message-ID: <20260430211351.658193-4-ynorov@nvidia.com> (raw)
In-Reply-To: <20260430211351.658193-1-ynorov@nvidia.com>

From: Jinjie Ruan <ruanjinjie@huawei.com>

Define generic __bitrev8/16/32 using the implementation
in <linux/bitrev.h>, so they can be reused in <asm/bitrev.h>,
such as RISCV.

Reviewed-by: Yury Norov <ynorov@nvidia.com>
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Signed-off-by: Yury Norov <ynorov@nvidia.com>
---
 include/asm-generic/bitops/__bitrev.h | 25 +++++++++++++++++++++++++
 include/linux/bitrev.h                | 20 ++++----------------
 2 files changed, 29 insertions(+), 16 deletions(-)
 create mode 100644 include/asm-generic/bitops/__bitrev.h

diff --git a/include/asm-generic/bitops/__bitrev.h b/include/asm-generic/bitops/__bitrev.h
new file mode 100644
index 000000000000..f06af929678d
--- /dev/null
+++ b/include/asm-generic/bitops/__bitrev.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_GENERIC_BITOPS___BITREV_H_
+#define _ASM_GENERIC_BITOPS___BITREV_H_
+
+#ifdef CONFIG_GENERIC_BITREVERSE
+#include <asm/types.h>
+
+extern u8 const byte_rev_table[256];
+static __always_inline __attribute_const__ u8 generic___bitrev8(u8 byte)
+{
+	return byte_rev_table[byte];
+}
+
+static __always_inline __attribute_const__ u16 generic___bitrev16(u16 x)
+{
+	return (generic___bitrev8(x & 0xff) << 8) | generic___bitrev8(x >> 8);
+}
+
+static __always_inline __attribute_const__ u32 generic___bitrev32(u32 x)
+{
+	return (generic___bitrev16(x & 0xffff) << 16) | generic___bitrev16(x >> 16);
+}
+#endif /* CONFIG_GENERIC_BITREVERSE */
+
+#endif /* _ASM_GENERIC_BITOPS___BITREV_H_ */
diff --git a/include/linux/bitrev.h b/include/linux/bitrev.h
index d35b8ec1c485..11620a70e776 100644
--- a/include/linux/bitrev.h
+++ b/include/linux/bitrev.h
@@ -12,22 +12,10 @@
 #define __bitrev8 __arch_bitrev8
 
 #else
-extern u8 const byte_rev_table[256];
-static inline u8 __bitrev8(u8 byte)
-{
-	return byte_rev_table[byte];
-}
-
-static inline u16 __bitrev16(u16 x)
-{
-	return (__bitrev8(x & 0xff) << 8) | __bitrev8(x >> 8);
-}
-
-static inline u32 __bitrev32(u32 x)
-{
-	return (__bitrev16(x & 0xffff) << 16) | __bitrev16(x >> 16);
-}
-
+#include <asm-generic/bitops/__bitrev.h>
+#define __bitrev32 generic___bitrev32
+#define __bitrev16 generic___bitrev16
+#define __bitrev8 generic___bitrev8
 #endif /* CONFIG_HAVE_ARCH_BITREVERSE */
 
 #define __bitrev8x4(x)	(__bitrev32(swab32(x)))
-- 
2.51.0


  parent reply	other threads:[~2026-04-30 21:14 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-04-30 21:13 [PATCH 0/6] lib: rework bitreverse Yury Norov
2026-04-30 21:13 ` [PATCH 1/6] lib: include crc32.h conditionally on CONFIG_CRC32 Yury Norov
2026-05-04  8:03   ` Arnd Bergmann
2026-05-04 12:43     ` David Laight
2026-05-04 16:46     ` Yury Norov
2026-05-04 17:18       ` Arnd Bergmann
2026-05-04 18:32         ` Yury Norov
2026-05-04 19:05           ` Arnd Bergmann
2026-04-30 21:13 ` [PATCH 2/6] lib/bitrev: Introduce GENERIC_BITREVERSE and cleanup Kconfig Yury Norov
2026-04-30 21:13 ` Yury Norov [this message]
2026-04-30 21:13 ` [PATCH 4/6] arch/riscv: Add bitrev.h file to support rev8 and brev8 Yury Norov
2026-04-30 21:13 ` [PATCH 5/6] lib: compile generic bitrev.c conditionally on GENERIC_BITREVERSE Yury Norov
2026-04-30 21:13 ` [PATCH 6/6] MAINTAINERS: BITOPS: include bitrev.[ch] Yury Norov
2026-05-02  1:40 ` [PATCH 0/6] lib: rework bitreverse Yury Norov

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