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-rw-r--r--include/linux/entry-common.h20
-rw-r--r--kernel/entry/common.c14
2 files changed, 32 insertions, 2 deletions
diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index e370be8121aa..7c581a4c3797 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 48d30ce2e00e..d6b73937dab3 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();
}