Messages in this thread Patch in this message | | | Date | Mon, 05 Jun 2023 19:16:17 -0000 | From | "tip-bot2 for Peter Zijlstra" <> | Subject | [tip: sched/core] math64: Always inline u128 version of mul_u64_u64_shr() |
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The following commit has been merged into the sched/core branch of tip:
Commit-ID: fc4a0db4149afcdae2527f0d8c376accca34adc9 Gitweb: https://git.kernel.org/tip/fc4a0db4149afcdae2527f0d8c376accca34adc9 Author: Peter Zijlstra <peterz@infradead.org> AuthorDate: Fri, 19 May 2023 12:21:05 +02:00 Committer: Peter Zijlstra <peterz@infradead.org> CommitterDate: Mon, 05 Jun 2023 21:11:06 +02:00
math64: Always inline u128 version of mul_u64_u64_shr()
In order to prevent the following complaint from happening, always inline the u128 variant of mul_u64_u64_shr() -- which is what x86_64 will use.
vmlinux.o: warning: objtool: read_hv_sched_clock_tsc+0x5a: call to mul_u64_u64_shr.constprop.0() leaves .noinstr.text section
It should compile into something like:
asm("mul %[mul];" "shrd %rdx, %rax, %cl" : "+&a" (a) : "c" shift, [mul] "r" (mul) : "d");
Which is silly not to inline, but it happens.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Michael Kelley <mikelley@microsoft.com> # Hyper-V Link: https://lore.kernel.org/r/20230519102715.637420396@infradead.org --- include/linux/math64.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/math64.h b/include/linux/math64.h index 8b9191a..bf74478 100644 --- a/include/linux/math64.h +++ b/include/linux/math64.h @@ -168,7 +168,7 @@ static __always_inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift) #endif /* mul_u64_u32_shr */ #ifndef mul_u64_u64_shr -static inline u64 mul_u64_u64_shr(u64 a, u64 mul, unsigned int shift) +static __always_inline u64 mul_u64_u64_shr(u64 a, u64 mul, unsigned int shift) { return (u64)(((unsigned __int128)a * mul) >> shift); }
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