linux-kernel - [PATCH v9 11/16] entry: Split syscall_exit_to_user_mode

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Message-ID: <20251204082123.2792067-12-ruanjinjie@huawei.com>
Date: Thu, 4 Dec 2025 16:21:18 +0800
From: Jinjie Ruan <ruanjinjie@...wei.com>
To: <catalin.marinas@....com>, <will@...nel.org>, <oleg@...hat.com>,
	<tglx@...utronix.de>, <peterz@...radead.org>, <luto@...nel.org>,
	<shuah@...nel.org>, <kees@...nel.org>, <wad@...omium.org>, <deller@....de>,
	<macro@...am.me.uk>, <charlie@...osinc.com>, <kevin.brodsky@....com>,
	<ldv@...ace.io>, <mark.rutland@....com>, <song@...nel.org>,
	<ryan.roberts@....com>, <ada.coupriediaz@....com>,
	<anshuman.khandual@....com>, <broonie@...nel.org>, <pengcan@...inos.cn>,
	<dvyukov@...gle.com>, <linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>, <linux-kselftest@...r.kernel.org>
CC: <ruanjinjie@...wei.com>
Subject: [PATCH v9 11/16] entry: Split syscall_exit_to_user_mode_work() for arch reuse

In the generic entry code, the beginning of
syscall_exit_to_user_mode_work() can be reused on arm64 so it makes
sense to split it.

In preparation for moving arm64 over to the generic entry
code, split out syscall_exit_to_user_mode_prepare() helper from
syscall_exit_to_user_mode_work().

No functional changes.

Reviewed-by: Kevin Brodsky <kevin.brodsky@....com>
Reviewed-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Jinjie Ruan <ruanjinjie@...wei.com>
---
 include/linux/entry-common.h | 35 ++++++++++++++++++++++-------------
 1 file changed, 22 insertions(+), 13 deletions(-)

diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index 7177436f0f9e..cd6dacb2d8bf 100644
--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -137,20 +137,11 @@ static __always_inline long syscall_enter_from_user_mode(struct pt_regs *regs, l
  */
 void syscall_exit_work(struct pt_regs *regs, unsigned long work);
 
-/**
- * syscall_exit_to_user_mode_work - Handle work before returning to user mode
- * @regs:	Pointer to currents pt_regs
- *
- * Same as step 1 and 2 of syscall_exit_to_user_mode() but without calling
- * exit_to_user_mode() to perform the final transition to user mode.
- *
- * Calling convention is the same as for syscall_exit_to_user_mode() and it
- * returns with all work handled and interrupts disabled. The caller must
- * invoke exit_to_user_mode() before actually switching to user mode to
- * make the final state transitions. Interrupts must stay disabled between
- * return from this function and the invocation of exit_to_user_mode().
+/*
+ * Syscall specific exit to user mode preparation. Runs with interrupts
+ * enabled.
  */
-static __always_inline void syscall_exit_to_user_mode_work(struct pt_regs *regs)
+static __always_inline void syscall_exit_to_user_mode_prepare(struct pt_regs *regs)
 {
 	unsigned long work = READ_ONCE(current_thread_info()->syscall_work);
 	unsigned long nr = syscall_get_nr(current, regs);
@@ -171,6 +162,24 @@ static __always_inline void syscall_exit_to_user_mode_work(struct pt_regs *regs)
 	 */
 	if (unlikely(work & SYSCALL_WORK_EXIT))
 		syscall_exit_work(regs, work);
+}
+
+/**
+ * syscall_exit_to_user_mode_work - Handle work before returning to user mode
+ * @regs:	Pointer to currents pt_regs
+ *
+ * Same as step 1 and 2 of syscall_exit_to_user_mode() but without calling
+ * exit_to_user_mode() to perform the final transition to user mode.
+ *
+ * Calling convention is the same as for syscall_exit_to_user_mode() and it
+ * returns with all work handled and interrupts disabled. The caller must
+ * invoke exit_to_user_mode() before actually switching to user mode to
+ * make the final state transitions. Interrupts must stay disabled between
+ * return from this function and the invocation of exit_to_user_mode().
+ */
+static __always_inline void syscall_exit_to_user_mode_work(struct pt_regs *regs)
+{
+	syscall_exit_to_user_mode_prepare(regs);
 	local_irq_disable_exit_to_user();
 	exit_to_user_mode_prepare(regs);
 }
-- 
2.34.1