entry: Move exit to usermode functions to header file

To allow inlining, move exit_to_user_mode() to
entry-common.h.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20231218074520.1998026-2-svens@linux.ibm.com

diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index d95ab85f96ba5a41527722cd9f4a6f6a29554c2e..6a6e98f3805fe29218a7c6979ad150ff9482baf7 100644 (file)
--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -7,6 +7,10 @@
 #include <linux/syscalls.h>
 #include <linux/seccomp.h>
 #include <linux/sched.h>
+#include <linux/context_tracking.h>
+#include <linux/livepatch.h>
+#include <linux/resume_user_mode.h>
+#include <linux/tick.h>
 
 #include <asm/entry-common.h>
 
@@ -258,6 +262,43 @@ static __always_inline void arch_exit_to_user_mode(void) { }
  */
 void arch_do_signal_or_restart(struct pt_regs *regs);
 
+/**
+ * exit_to_user_mode_loop - do any pending work before leaving to user space
+ */
+unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
+                                    unsigned long ti_work);
+
+/**
+ * exit_to_user_mode_prepare - call exit_to_user_mode_loop() if required
+ * @regs:      Pointer to pt_regs on entry stack
+ *
+ * 1) check that interrupts are disabled
+ * 2) call tick_nohz_user_enter_prepare()
+ * 3) call exit_to_user_mode_loop() if any flags from
+ *    EXIT_TO_USER_MODE_WORK are set
+ * 4) check that interrupts are still disabled
+ */
+static __always_inline void exit_to_user_mode_prepare(struct pt_regs *regs)
+{
+       unsigned long ti_work;
+
+       lockdep_assert_irqs_disabled();
+
+       /* Flush pending rcuog wakeup before the last need_resched() check */
+       tick_nohz_user_enter_prepare();
+
+       ti_work = read_thread_flags();
+       if (unlikely(ti_work & EXIT_TO_USER_MODE_WORK))
+               ti_work = exit_to_user_mode_loop(regs, ti_work);
+
+       arch_exit_to_user_mode_prepare(regs, ti_work);
+
+       /* Ensure that kernel state is sane for a return to userspace */
+       kmap_assert_nomap();
+       lockdep_assert_irqs_disabled();
+       lockdep_sys_exit();
+}
+
 /**
  * exit_to_user_mode - Fixup state when exiting to user mode
  *
@@ -276,7 +317,17 @@ void arch_do_signal_or_restart(struct pt_regs *regs);
  * non-instrumentable.
  * The caller has to invoke syscall_exit_to_user_mode_work() before this.
  */
-void exit_to_user_mode(void);
+static __always_inline void exit_to_user_mode(void)
+{
+       instrumentation_begin();
+       trace_hardirqs_on_prepare();
+       lockdep_hardirqs_on_prepare();
+       instrumentation_end();
+
+       user_enter_irqoff();
+       arch_exit_to_user_mode();
+       lockdep_hardirqs_on(CALLER_ADDR0);
+}
 
 /**
  * syscall_exit_to_user_mode_work - Handle work before returning to user mode

diff --git a/kernel/entry/common.c b/kernel/entry/common.c
index d7ee4bc3f2ba3e6d7a8d5976952e646430d46648..7f8f8c16140a7ae4b7b8d4d3efec7b3a15eeeb1d 100644 (file)
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -123,29 +123,16 @@ noinstr void syscall_enter_from_user_mode_prepare(struct pt_regs *regs)
        instrumentation_end();
 }
 
-/* See comment for exit_to_user_mode() in entry-common.h */
-static __always_inline void __exit_to_user_mode(void)
-{
-       instrumentation_begin();
-       trace_hardirqs_on_prepare();
-       lockdep_hardirqs_on_prepare();
-       instrumentation_end();
-
-       user_enter_irqoff();
-       arch_exit_to_user_mode();
-       lockdep_hardirqs_on(CALLER_ADDR0);
-}
-
-void noinstr exit_to_user_mode(void)
-{
-       __exit_to_user_mode();
-}
-
 /* Workaround to allow gradual conversion of architecture code */
 void __weak arch_do_signal_or_restart(struct pt_regs *regs) { }
 
-static unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
-                                           unsigned long ti_work)
+/**
+ * exit_to_user_mode_loop - do any pending work before leaving to user space
+ * @regs:      Pointer to pt_regs on entry stack
+ * @ti_work:   TIF work flags as read by the caller
+ */
+__always_inline unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
+                                                    unsigned long ti_work)
 {
        /*
         * Before returning to user space ensure that all pending work
@@ -190,27 +177,6 @@ static unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
        return ti_work;
 }
 
-static void exit_to_user_mode_prepare(struct pt_regs *regs)
-{
-       unsigned long ti_work;
-
-       lockdep_assert_irqs_disabled();
-
-       /* Flush pending rcuog wakeup before the last need_resched() check */
-       tick_nohz_user_enter_prepare();
-
-       ti_work = read_thread_flags();
-       if (unlikely(ti_work & EXIT_TO_USER_MODE_WORK))
-               ti_work = exit_to_user_mode_loop(regs, ti_work);
-
-       arch_exit_to_user_mode_prepare(regs, ti_work);
-
-       /* Ensure that kernel state is sane for a return to userspace */
-       kmap_assert_nomap();
-       lockdep_assert_irqs_disabled();
-       lockdep_sys_exit();
-}
-
 /*
  * If SYSCALL_EMU is set, then the only reason to report is when
  * SINGLESTEP is set (i.e. PTRACE_SYSEMU_SINGLESTEP).  This syscall
@@ -295,7 +261,7 @@ __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();
+       exit_to_user_mode();
 }
 
 noinstr void irqentry_enter_from_user_mode(struct pt_regs *regs)
@@ -308,7 +274,7 @@ noinstr void irqentry_exit_to_user_mode(struct pt_regs *regs)
        instrumentation_begin();
        exit_to_user_mode_prepare(regs);
        instrumentation_end();
-       __exit_to_user_mode();
+       exit_to_user_mode();
 }
 
 noinstr irqentry_state_t irqentry_enter(struct pt_regs *regs)