From: "tip-bot2 for Sven Schnelle" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Sven Schnelle <svens@linux.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: core/entry] entry: Add syscall_exit_to_user_mode_work()
Date: Wed, 02 Dec 2020 09:38:26 -0000 [thread overview]
Message-ID: <160690190640.3364.10751265538936902967.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20201201142755.31931-6-svens@linux.ibm.com>
The following commit has been merged into the core/entry branch of tip:
Commit-ID: 1568b5540b3e6ff3fe43a2cf889cb777cf8149fc
Gitweb: https://git.kernel.org/tip/1568b5540b3e6ff3fe43a2cf889cb777cf8149fc
Author: Sven Schnelle <svens@linux.ibm.com>
AuthorDate: Tue, 01 Dec 2020 15:27:55 +01:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Wed, 02 Dec 2020 10:32:18 +01:00
entry: Add syscall_exit_to_user_mode_work()
This is the same as syscall_exit_to_user_mode() but without calling
exit_to_user_mode(). This can be used if there is an architectural reason
to avoid the combo function, e.g. restarting a syscall without returning to
userspace. Before returning to user space the caller has to invoke
exit_to_user_mode().
[ tglx: Amended comments ]
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201201142755.31931-6-svens@linux.ibm.com
---
include/linux/entry-common.h | 20 ++++++++++++++++++++
kernel/entry/common.c | 14 ++++++++++++--
2 files changed, 32 insertions(+), 2 deletions(-)
diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index e370be8..7c581a4 100644
--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -316,10 +316,26 @@ static inline void arch_syscall_exit_tracehook(struct pt_regs *regs, bool step)
* is not suitable as the last step before returning to userspace. Must be
* invoked with interrupts disabled and the caller must be
* non-instrumentable.
+ * The caller has to invoke syscall_exit_to_user_mode_work() before this.
*/
void exit_to_user_mode(void);
/**
+ * 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().
+ */
+void syscall_exit_to_user_mode_work(struct pt_regs *regs);
+
+/**
* syscall_exit_to_user_mode - Handle work before returning to user mode
* @regs: Pointer to currents pt_regs
*
@@ -343,6 +359,10 @@ void exit_to_user_mode(void);
*
* 3) Final transition (lockdep, tracing, context tracking, RCU), i.e. the
* functionality in exit_to_user_mode().
+ *
+ * This is a combination of syscall_exit_to_user_mode_work() (1,2) and
+ * exit_to_user_mode(). This function is preferred unless there is a
+ * compelling architectural reason to use the seperate functions.
*/
void syscall_exit_to_user_mode(struct pt_regs *regs);
diff --git a/kernel/entry/common.c b/kernel/entry/common.c
index 48d30ce..d6b7393 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -282,12 +282,22 @@ static void syscall_exit_to_user_mode_prepare(struct pt_regs *regs)
syscall_exit_work(regs, work);
}
-__visible noinstr void syscall_exit_to_user_mode(struct pt_regs *regs)
+static __always_inline void __syscall_exit_to_user_mode_work(struct pt_regs *regs)
{
- instrumentation_begin();
syscall_exit_to_user_mode_prepare(regs);
local_irq_disable_exit_to_user();
exit_to_user_mode_prepare(regs);
+}
+
+void syscall_exit_to_user_mode_work(struct pt_regs *regs)
+{
+ __syscall_exit_to_user_mode_work(regs);
+}
+
+__visible noinstr void syscall_exit_to_user_mode(struct pt_regs *regs)
+{
+ instrumentation_begin();
+ __syscall_exit_to_user_mode_work(regs);
instrumentation_end();
__exit_to_user_mode();
}
next prev parent reply other threads:[~2020-12-02 9:39 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-01 14:27 [PATCH v2] split up lockdep and syscall related functionality in generic entry code Sven Schnelle
2020-12-01 14:27 ` [PATCH v2 1/5] entry: rename enter_from_user_mode() Sven Schnelle
2020-12-02 9:38 ` [tip: core/entry] entry: Rename enter_from_user_mode() tip-bot2 for Sven Schnelle
2020-12-02 14:12 ` tip-bot2 for Sven Schnelle
2020-12-01 14:27 ` [PATCH v2 2/5] entry: rename exit_from_user_mode() Sven Schnelle
2020-12-01 14:41 ` Sven Schnelle
2020-12-02 9:38 ` [tip: core/entry] entry: Rename exit_to_user_mode() tip-bot2 for Sven Schnelle
2020-12-02 14:12 ` tip-bot2 for Sven Schnelle
2020-12-01 14:27 ` [PATCH v2 3/5] entry: add enter_from_user_mode() wrapper Sven Schnelle
2020-12-02 9:38 ` [tip: core/entry] entry_Add_enter_from_user_mode_wrapper tip-bot2 for Sven Schnelle
2020-12-02 14:12 ` tip-bot2 for Sven Schnelle
2020-12-01 14:27 ` [PATCH v2 4/5] entry: add exit_to_user_mode() wrapper Sven Schnelle
2020-12-02 9:38 ` [tip: core/entry] entry: Add " tip-bot2 for Sven Schnelle
2020-12-02 14:12 ` tip-bot2 for Sven Schnelle
2020-12-01 14:27 ` [PATCH v2 5/5] entry: add syscall_exit_to_user_mode_work() Sven Schnelle
2020-12-02 9:38 ` tip-bot2 for Sven Schnelle [this message]
2020-12-02 14:12 ` [tip: core/entry] entry: Add syscall_exit_to_user_mode_work() tip-bot2 for Sven Schnelle
2020-12-01 23:17 ` [PATCH v2] split up lockdep and syscall related functionality in generic entry code Thomas Gleixner
2020-12-02 0:33 ` Thomas Gleixner
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