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m68k: hash: Use lower_16_bits() helper

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When building for m68k with CONFIG_M68000=y and C=1:

    drivers/clk/rockchip/clk-rk3528.c: note: in included file (through include/linux/hash.h, include/linux/slab.h):
    arch/m68k/include/asm/hash.h:57:24: warning: cast truncates bits from constant value (18720 becomes 8720)
    arch/m68k/include/asm/hash.h:57:24: warning: cast truncates bits from constant value (1e8e8 becomes e8e8)

Sparse does not realize the truncation is intentional.
Make this explicit by using the lower_16_bits() helper instead, which
also masks the unwanted bits.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202605191434.PQkj2Rki-lkp@intel.com/
Reported-by: Heiko Stuebner <heiko@sntech.de>
Closes: https://lore.kernel.org/20260603213726.1025094-1-heiko@sntech.de/
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Daniel Palmer <daniel@thingy.jp>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Link: https://patch.msgid.link/b55e9bd0532c0cad519809c86e0a8400060d75a1.1780559561.git.geert@linux-m68k.org
This commit is contained in:
Geert Uytterhoeven 2026-06-04 09:54:23 +02:00
parent 0179337431
commit 7d4ea0365c
1 changed files with 3 additions and 1 deletions
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4
arch/m68k/include/asm/hash.h
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@ -2,6 +2,8 @@
#ifndef _ASM_HASH_H
#define _ASM_HASH_H
#include <linux/wordpart.h>
/*
* If CONFIG_M68000=y (original mc68000/010), this file is #included
* to work around the lack of a MULU.L instruction.
@ -54,7 +56,7 @@ static inline u32 __attribute_const__ __hash_32(u32 x)
: "=&d,d" (a), "=&r,r" (b)
: "r,roi?" (x)); /* a+b = x*0x8647 */
return ((u16)(x*0x61c8) << 16) + a + b;
return (lower_16_bits(x * 0x61c8) << 16) + a + b;
}
#endif /* _ASM_HASH_H */