[PATCH v2 3/5] entry: add enter_from_user_mode() wrapper

From: Sven Schnelle
Date: Tue Dec 01 2020 - 09:29:01 EST


Can be called from architecture dependent code, and simply
calls __enter_from_user_mode(). This way __enter_from_user_mode
can still be inlined because it is declared static.

Signed-off-by: Sven Schnelle <svens@xxxxxxxxxxxxx>
---
include/linux/entry-common.h | 11 +++++++++++
kernel/entry/common.c | 15 +++++----------
2 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index 474f29638d2c..28a8554fad7d 100644
--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -402,4 +402,15 @@ void irqentry_exit_cond_resched(void);
*/
void noinstr irqentry_exit(struct pt_regs *regs, irqentry_state_t state);

+/**
+ * enter_from_user_mode - Establish state when coming from user mode
+ *
+ * Syscall/interrupt entry disables interrupts, but user mode is traced as
+ * interrupts enabled. Also with NO_HZ_FULL RCU might be idle.
+ *
+ * 1) Tell lockdep that interrupts are disabled
+ * 2) Invoke context tracking if enabled to reactivate RCU
+ * 3) Trace interrupts off state
+ */
+void enter_from_user_mode(struct pt_regs *regs);
#endif
diff --git a/kernel/entry/common.c b/kernel/entry/common.c
index 076ee1cde67f..ee588ee9f122 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -8,16 +8,6 @@
#define CREATE_TRACE_POINTS
#include <trace/events/syscalls.h>

-/**
- * __enter_from_user_mode - Establish state when coming from user mode
- *
- * Syscall/interrupt entry disables interrupts, but user mode is traced as
- * interrupts enabled. Also with NO_HZ_FULL RCU might be idle.
- *
- * 1) Tell lockdep that interrupts are disabled
- * 2) Invoke context tracking if enabled to reactivate RCU
- * 3) Trace interrupts off state
- */
static __always_inline void __enter_from_user_mode(struct pt_regs *regs)
{
arch_check_user_regs(regs);
@@ -31,6 +21,11 @@ static __always_inline void __enter_from_user_mode(struct pt_regs *regs)
instrumentation_end();
}

+void noinstr enter_from_user_mode(struct pt_regs *regs)
+{
+ __enter_from_user_mode(regs);
+}
+
static inline void syscall_enter_audit(struct pt_regs *regs, long syscall)
{
if (unlikely(audit_context())) {
--
2.17.1