linux-kernel - [PATCH 02/10] kernel: entry: Expose helpers to migrate TIF to SYSCALL

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Date:   Fri, 13 Nov 2020 22:29:09 -0500
From:   Gabriel Krisman Bertazi <krisman@...labora.com>
To:     tglx@...utronix.de
Cc:     mingo@...hat.com, keescook@...omium.org, arnd@...db.de,
        luto@...capital.net, wad@...omium.org, rostedt@...dmis.org,
        paul@...l-moore.com, eparis@...hat.com, oleg@...hat.com,
        linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org,
        x86@...nel.org, Gabriel Krisman Bertazi <krisman@...labora.com>,
        kernel@...labora.com
Subject: [PATCH 02/10] kernel: entry: Expose helpers to migrate TIF to SYSCALL_WORK flags

With the goal to split the syscall work related flags into a separate field
that is architecture independent, expose transitional helpers that
resolve to either the TIF flags or to the corresponding SYSCALL_WORK
flags.  This will allow architectures to migrate only when they port to
the generic syscall entry code.

Signed-off-by: Gabriel Krisman Bertazi <krisman@...labora.com>
---
 include/linux/thread_info.h | 42 +++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
index e93e249a4e9b..18755373dc4d 100644
--- a/include/linux/thread_info.h
+++ b/include/linux/thread_info.h
@@ -97,6 +97,48 @@ static inline int test_ti_thread_flag(struct thread_info *ti, int flag)
 #define test_thread_flag(flag) \
 	test_ti_thread_flag(current_thread_info(), flag)
 
+#ifdef CONFIG_GENERIC_ENTRY
+static inline void __set_task_syscall_work(struct thread_info *ti, int flag)
+{
+	set_bit(flag, (unsigned long *)&ti->syscall_work);
+}
+static inline int __test_task_syscall_work(struct thread_info *ti, int flag)
+{
+	return test_bit(flag, (unsigned long *)&ti->syscall_work);
+}
+static inline void __clear_task_syscall_work(struct thread_info *ti, int flag)
+{
+	return clear_bit(flag, (unsigned long *)&ti->syscall_work);
+}
+#define set_syscall_work(fl) \
+	__set_task_syscall_work(current_thread_info(), SYSCALL_WORK_##fl)
+#define test_syscall_work(fl) \
+	__test_task_syscall_work(current_thread_info(), SYSCALL_WORK_##fl)
+#define clear_syscall_work(fl) \
+	__clear_task_syscall_work(current_thread_info(), SYSCALL_WORK_##fl)
+
+#define set_task_syscall_work(t, fl) \
+	__set_task_syscall_work(task_thread_info(t), SYSCALL_WORK_##fl)
+#define test_task_syscall_work(t, fl) \
+	__test_task_syscall_work(task_thread_info(t), SYSCALL_WORK_##fl)
+#define clear_task_syscall_work(t, fl) \
+	__clear_task_syscall_work(task_thread_info(t), SYSCALL_WORK_##fl)
+#else
+#define set_syscall_work(fl) \
+	set_ti_thread_flag(current_thread_info(), SYSCALL_WORK_##fl)
+#define test_syscall_work(fl) \
+	test_ti_thread_flag(current_thread_info(), SYSCALL_WORK_##fl)
+#define clear_syscall_work(fl) \
+	clear_ti_thread_flag(current_thread_info(), SYSCALL_WORK_##fl)
+
+#define set_task_syscall_work(t, fl) \
+	set_ti_thread_flag(task_thread_info(t), TIF_##fl)
+#define test_task_syscall_work(t, fl) \
+	test_ti_thread_flag(task_thread_info(t), TIF_##fl)
+#define clear_task_syscall_work(t, fl) \
+	clear_ti_thread_flag(task_thread_info(t), TIF_##fl)
+#endif /* CONFIG_GENERIC_ENTRY */
+
 #define tif_need_resched() test_thread_flag(TIF_NEED_RESCHED)
 
 #ifndef CONFIG_HAVE_ARCH_WITHIN_STACK_FRAMES
-- 
2.29.2