From f46ccdb87a2573a23ee2d2c21a6b087af9ae76c0 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Tue, 16 Sep 2025 15:48:03 +0200 Subject: [PATCH] s390/bitops: Cleanup __flogr() The flogr() inline assembly has no side effects and generates the same output if the input does not change. Therefore remove the volatile qualifier to allow the compiler to optimize the inline assembly away, if possible. Also remove the superfluous '\n' which makes the inline assembly appear larger than it is according to compiler heuristics (number of lines). Furthermore change the return type of flogr() to unsigned long and add the const attribute to the function. This reduces the kernel image size by 994 bytes (defconfig, gcc 15.2.0). Suggested-by: Juergen Christ Reviewed-by: Juergen Christ Signed-off-by: Heiko Carstens Signed-off-by: Alexander Gordeev --- arch/s390/include/asm/bitops.h | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/arch/s390/include/asm/bitops.h b/arch/s390/include/asm/bitops.h index ac94672db8170..e643f24ebc05e 100644 --- a/arch/s390/include/asm/bitops.h +++ b/arch/s390/include/asm/bitops.h @@ -130,7 +130,7 @@ static inline bool test_bit_inv(unsigned long nr, * where the most significant bit has bit number 0. * If no bit is set this function returns 64. */ -static __always_inline unsigned char __flogr(unsigned long word) +static __always_inline __attribute_const__ unsigned long __flogr(unsigned long word) { unsigned long bit; @@ -167,9 +167,8 @@ static __always_inline unsigned char __flogr(unsigned long word) union register_pair rp __uninitialized; rp.even = word; - asm volatile( - " flogr %[rp],%[rp]\n" - : [rp] "+d" (rp.pair) : : "cc"); + asm("flogr %[rp],%[rp]" + : [rp] "+d" (rp.pair) : : "cc"); bit = rp.even; /* * The result of the flogr instruction is a value in the range -- 2.47.3