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b=hQiy30AsC0rVH+L+AwFPJyBV0uKaC3ziwvcd3OQUrlaDfIEZKbE3hyLtinM0Hf7hi L6TdwkiVFbA7K78sQ4kihcsZk+s2Vs8bXVQ+pX9kYp74atNi9wiQLqgdA+/xcgBhEu HzX2vQzXjOo3S7GR9Ee90wRzcS8zuKezV5NTryoDQGkCyyLf88KSACQLtnrpMBUOiU NQen1FPyaPIC9Lbssw8Y6AXIKPkE1X6kvoGFxAaMHTCWw9NozhmFP+UB4Bf3hU2fZv jKPyEgOKgVxcmfWk1GZxMzVF2Wa7ueLuUVy+IMY8c9zANLc+c59asuw2QugrEM9LQ2 DmBZTOvRmlTxg== From: Sasha Levin To: stable@vger.kernel.org, chenhuacai@kernel.org Cc: Xiaotian Wu , Miao Wang , Xing Li , Hongchen Zhang , Rui Wang , Huacai Chen , linux-mm@kvack.org, loongarch@lists.linux.dev, linux-kernel@vger.kernel.org Subject: FAILED: Patch "LoongArch: Change __my_cpu_offset definition to avoid mis-optimization" failed to apply to 5.15-stable tree Date: Wed, 27 Mar 2024 08:15:16 -0400 Message-ID: <20240327121516.2831778-1-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 MIME-Version: 1.0 X-Patchwork-Hint: ignore X-stable: review Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 30B73180009 X-Rspam-User: X-Rspamd-Server: rspam04 X-Stat-Signature: 88jwwgtk565akro4gwn3tusac4qafntr X-HE-Tag: 1711541719-256510 X-HE-Meta: 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 LOvcoF/N OB4JQPcxKnVC9824LPrPpHOtsAjhYCsChCuHDqm1qHEhPH6TlfUBIForrATjWGXB98IrxoK8KIB7yiI0mJhZtgs1R+UQt+hvWBe7Hs77BY6rdudTfBISHeMwUgTY/VbehknULIc5NDlfthbAFFokLPt5e8xZaIUO2LcpN+fd+EEpXfYmgqrUEG/oOGgFGOi8BwY5Obl1paoBtcaq5EuTfHLIgL164xSIT07dfohu6OTNLNzghsjdF00y2vuBCOK5APKXinlc3S3EbGCe93q+ss9aFEGktPGKq/5TEg2wlXRXkg5dx8098M82e0QL/AXFoBNM5ZQo9Wyv3Gmb1N+DQNxV0yw/5ShStC4egpcrfwr+EyuLV+surkNR0cPJSPfo5il46 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From c87e12e0e8c1241410e758e181ca6bf23efa5b5b Mon Sep 17 00:00:00 2001 From: Huacai Chen Date: Tue, 19 Mar 2024 15:50:34 +0800 Subject: [PATCH] LoongArch: Change __my_cpu_offset definition to avoid mis-optimization >From GCC commit 3f13154553f8546a ("df-scan: remove ad-hoc handling of global regs in asms"), global registers will no longer be forced to add to the def-use chain. Then current_thread_info(), current_stack_pointer and __my_cpu_offset may be lifted out of the loop because they are no longer treated as "volatile variables". This optimization is still correct for the current_thread_info() and current_stack_pointer usages because they are associated to a thread. However it is wrong for __my_cpu_offset because it is associated to a CPU rather than a thread: if the thread migrates to a different CPU in the loop, __my_cpu_offset should be changed. Change __my_cpu_offset definition to treat it as a "volatile variable", in order to avoid such a mis-optimization. Cc: stable@vger.kernel.org Reported-by: Xiaotian Wu Reported-by: Miao Wang Signed-off-by: Xing Li Signed-off-by: Hongchen Zhang Signed-off-by: Rui Wang Signed-off-by: Huacai Chen --- arch/loongarch/include/asm/percpu.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/loongarch/include/asm/percpu.h b/arch/loongarch/include/asm/percpu.h index 9b36ac003f890..8f290e5546cf7 100644 --- a/arch/loongarch/include/asm/percpu.h +++ b/arch/loongarch/include/asm/percpu.h @@ -29,7 +29,12 @@ static inline void set_my_cpu_offset(unsigned long off) __my_cpu_offset = off; csr_write64(off, PERCPU_BASE_KS); } -#define __my_cpu_offset __my_cpu_offset + +#define __my_cpu_offset \ +({ \ + __asm__ __volatile__("":"+r"(__my_cpu_offset)); \ + __my_cpu_offset; \ +}) #define PERCPU_OP(op, asm_op, c_op) \ static __always_inline unsigned long __percpu_##op(void *ptr, \ -- 2.43.0