arm64: Optimize ttwu IPI

hulk inclusion
category: feature
bugzilla: 47727
CVE: NA

------------------------------

When it is to wake up a task in a remote cpu shared LLC , we can
simply set need_resched flag, waking up a cpu that is in polling
idle. This wakeup action does not require an IPI.

But the premise is that it need to support _TIF_POLLING_NRFLAG
Signed-off-by: NXiangyou Xie <xiexiangyou@huawei.com>
Signed-off-by: NPeng Liang <liangpeng10@huawei.com>
Reviewed-by: NHanjun Guo <guohanjun@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

arch/arm64/include/asm/thread_info.h

@@ -73,6 +73,7 @@ void arch_release_task_struct(struct task_struct *tsk);
 #define TIF_SYSCALL_TRACEPOINT	10	/* syscall tracepoint for ftrace */
 #define TIF_SECCOMP		11	/* syscall secure computing */
 #define TIF_SYSCALL_EMU		12	/* syscall emulation active */
+#define TIF_POLLING_NRFLAG	16	/* idle is polling for TIF_NEED_RESCHED */
 #define TIF_MEMDIE		18	/* is terminating due to OOM killer */
 #define TIF_FREEZE		19
 #define TIF_RESTORE_SIGMASK	20
@@ -100,6 +101,7 @@ void arch_release_task_struct(struct task_struct *tsk);
 #define _TIF_SVE		(1 << TIF_SVE)
 #define _TIF_MTE_ASYNC_FAULT	(1 << TIF_MTE_ASYNC_FAULT)
 #define _TIF_32BIT_AARCH64	(1 << TIF_32BIT_AARCH64)
+#define _TIF_POLLING_NRFLAG	(1 << TIF_POLLING_NRFLAG)
 
 #define _TIF_WORK_MASK		(_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
 				 _TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE | \