diff mbox series

[v2,1/3] entry: move exit to usermode functions to header file

Message ID 20231218074520.1998026-2-svens@linux.ibm.com
State New
Headers
Series entry: inline syscall enter/exit functions |

Commit Message

Sven Schnelle Dec. 18, 2023, 7:45 a.m. UTC 
  To allow inlining, move exit_to_user_mode() to
entry-common.h.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
---
 include/linux/entry-common.h | 52 +++++++++++++++++++++++++++++++++++-
 kernel/entry/common.c        | 50 +++++-----------------------------
 2 files changed, 58 insertions(+), 44 deletions(-)

Comments

kernel test robot Dec. 18, 2023, 6:31 p.m. UTC | #1 
Hi Sven,

kernel test robot noticed the following build warnings:

[auto build test WARNING on tip/core/entry]
[also build test WARNING on linus/master v6.7-rc6 next-20231218]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Sven-Schnelle/entry-move-exit-to-usermode-functions-to-header-file/20231218-154733
base:   tip/core/entry
patch link:    https://lore.kernel.org/r/20231218074520.1998026-2-svens%40linux.ibm.com
patch subject: [PATCH v2 1/3] entry: move exit to usermode functions to header file
config: x86_64-randconfig-161-20231218 (https://download.01.org/0day-ci/archive/20231219/202312190205.LbtmWWZN-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231219/202312190205.LbtmWWZN-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202312190205.LbtmWWZN-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> kernel/entry/common.c:134: warning: Function parameter or member 'regs' not described in 'exit_to_user_mode_loop'
>> kernel/entry/common.c:134: warning: Function parameter or member 'ti_work' not described in 'exit_to_user_mode_loop'


vim +134 kernel/entry/common.c

a9f3a74a29af09 Thomas Gleixner     2020-07-22  128  
af18f155cb4bda Sven Schnelle       2023-12-18  129  /**
af18f155cb4bda Sven Schnelle       2023-12-18  130   * exit_to_user_mode_loop - do any pending work before leaving to user space
af18f155cb4bda Sven Schnelle       2023-12-18  131   */
af18f155cb4bda Sven Schnelle       2023-12-18  132  __always_inline unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
a9f3a74a29af09 Thomas Gleixner     2020-07-22  133  						     unsigned long ti_work)
a9f3a74a29af09 Thomas Gleixner     2020-07-22 @134  {
a9f3a74a29af09 Thomas Gleixner     2020-07-22  135  	/*
a9f3a74a29af09 Thomas Gleixner     2020-07-22  136  	 * Before returning to user space ensure that all pending work
a9f3a74a29af09 Thomas Gleixner     2020-07-22  137  	 * items have been completed.
a9f3a74a29af09 Thomas Gleixner     2020-07-22  138  	 */
a9f3a74a29af09 Thomas Gleixner     2020-07-22  139  	while (ti_work & EXIT_TO_USER_MODE_WORK) {
a9f3a74a29af09 Thomas Gleixner     2020-07-22  140  
a9f3a74a29af09 Thomas Gleixner     2020-07-22  141  		local_irq_enable_exit_to_user(ti_work);
a9f3a74a29af09 Thomas Gleixner     2020-07-22  142  
a9f3a74a29af09 Thomas Gleixner     2020-07-22  143  		if (ti_work & _TIF_NEED_RESCHED)
a9f3a74a29af09 Thomas Gleixner     2020-07-22  144  			schedule();
a9f3a74a29af09 Thomas Gleixner     2020-07-22  145  
a9f3a74a29af09 Thomas Gleixner     2020-07-22  146  		if (ti_work & _TIF_UPROBE)
a9f3a74a29af09 Thomas Gleixner     2020-07-22  147  			uprobe_notify_resume(regs);
a9f3a74a29af09 Thomas Gleixner     2020-07-22  148  
a9f3a74a29af09 Thomas Gleixner     2020-07-22  149  		if (ti_work & _TIF_PATCH_PENDING)
a9f3a74a29af09 Thomas Gleixner     2020-07-22  150  			klp_update_patch_state(current);
a9f3a74a29af09 Thomas Gleixner     2020-07-22  151  
12db8b690010cc Jens Axboe          2020-10-26  152  		if (ti_work & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
8ba62d37949e24 Eric W. Biederman   2022-02-09  153  			arch_do_signal_or_restart(regs);
a9f3a74a29af09 Thomas Gleixner     2020-07-22  154  
a68de80f61f6af Sean Christopherson 2021-09-01  155  		if (ti_work & _TIF_NOTIFY_RESUME)
03248addadf1a5 Eric W. Biederman   2022-02-09  156  			resume_user_mode_work(regs);
a9f3a74a29af09 Thomas Gleixner     2020-07-22  157  
a9f3a74a29af09 Thomas Gleixner     2020-07-22  158  		/* Architecture specific TIF work */
a9f3a74a29af09 Thomas Gleixner     2020-07-22  159  		arch_exit_to_user_mode_work(regs, ti_work);
a9f3a74a29af09 Thomas Gleixner     2020-07-22  160  
a9f3a74a29af09 Thomas Gleixner     2020-07-22  161  		/*
a9f3a74a29af09 Thomas Gleixner     2020-07-22  162  		 * Disable interrupts and reevaluate the work flags as they
a9f3a74a29af09 Thomas Gleixner     2020-07-22  163  		 * might have changed while interrupts and preemption was
a9f3a74a29af09 Thomas Gleixner     2020-07-22  164  		 * enabled above.
a9f3a74a29af09 Thomas Gleixner     2020-07-22  165  		 */
a9f3a74a29af09 Thomas Gleixner     2020-07-22  166  		local_irq_disable_exit_to_user();
47b8ff194c1fd7 Frederic Weisbecker 2021-02-01  167  
47b8ff194c1fd7 Frederic Weisbecker 2021-02-01  168  		/* Check if any of the above work has queued a deferred wakeup */
f268c3737ecaef Frederic Weisbecker 2021-05-27  169  		tick_nohz_user_enter_prepare();
47b8ff194c1fd7 Frederic Weisbecker 2021-02-01  170  
6ce895128b3bff Mark Rutland        2021-11-29  171  		ti_work = read_thread_flags();
a9f3a74a29af09 Thomas Gleixner     2020-07-22  172  	}
a9f3a74a29af09 Thomas Gleixner     2020-07-22  173  
a9f3a74a29af09 Thomas Gleixner     2020-07-22  174  	/* Return the latest work state for arch_exit_to_user_mode() */
a9f3a74a29af09 Thomas Gleixner     2020-07-22  175  	return ti_work;
a9f3a74a29af09 Thomas Gleixner     2020-07-22  176  }
a9f3a74a29af09 Thomas Gleixner     2020-07-22  177
kernel test robot Dec. 20, 2023, 9:35 p.m. UTC | #2 
Hi Sven,

kernel test robot noticed the following build warnings:

[auto build test WARNING on tip/core/entry]
[also build test WARNING on linus/master v6.7-rc6 next-20231220]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Sven-Schnelle/entry-move-exit-to-usermode-functions-to-header-file/20231218-154733
base:   tip/core/entry
patch link:    https://lore.kernel.org/r/20231218074520.1998026-2-svens%40linux.ibm.com
patch subject: [PATCH v2 1/3] entry: move exit to usermode functions to header file
config: x86_64-rhel-8.3-kunit (https://download.01.org/0day-ci/archive/20231221/202312210535.lQDyVDDW-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231221/202312210535.lQDyVDDW-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202312210535.lQDyVDDW-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> kernel/entry/common.c:134: warning: Function parameter or struct member 'regs' not described in 'exit_to_user_mode_loop'
>> kernel/entry/common.c:134: warning: Function parameter or struct member 'ti_work' not described in 'exit_to_user_mode_loop'


vim +134 kernel/entry/common.c

a9f3a74a29af09 Thomas Gleixner     2020-07-22  128  
af18f155cb4bda Sven Schnelle       2023-12-18  129  /**
af18f155cb4bda Sven Schnelle       2023-12-18  130   * exit_to_user_mode_loop - do any pending work before leaving to user space
af18f155cb4bda Sven Schnelle       2023-12-18  131   */
af18f155cb4bda Sven Schnelle       2023-12-18  132  __always_inline unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
a9f3a74a29af09 Thomas Gleixner     2020-07-22  133  						     unsigned long ti_work)
a9f3a74a29af09 Thomas Gleixner     2020-07-22 @134  {
a9f3a74a29af09 Thomas Gleixner     2020-07-22  135  	/*
a9f3a74a29af09 Thomas Gleixner     2020-07-22  136  	 * Before returning to user space ensure that all pending work
a9f3a74a29af09 Thomas Gleixner     2020-07-22  137  	 * items have been completed.
a9f3a74a29af09 Thomas Gleixner     2020-07-22  138  	 */
a9f3a74a29af09 Thomas Gleixner     2020-07-22  139  	while (ti_work & EXIT_TO_USER_MODE_WORK) {
a9f3a74a29af09 Thomas Gleixner     2020-07-22  140  
a9f3a74a29af09 Thomas Gleixner     2020-07-22  141  		local_irq_enable_exit_to_user(ti_work);
a9f3a74a29af09 Thomas Gleixner     2020-07-22  142  
a9f3a74a29af09 Thomas Gleixner     2020-07-22  143  		if (ti_work & _TIF_NEED_RESCHED)
a9f3a74a29af09 Thomas Gleixner     2020-07-22  144  			schedule();
a9f3a74a29af09 Thomas Gleixner     2020-07-22  145  
a9f3a74a29af09 Thomas Gleixner     2020-07-22  146  		if (ti_work & _TIF_UPROBE)
a9f3a74a29af09 Thomas Gleixner     2020-07-22  147  			uprobe_notify_resume(regs);
a9f3a74a29af09 Thomas Gleixner     2020-07-22  148  
a9f3a74a29af09 Thomas Gleixner     2020-07-22  149  		if (ti_work & _TIF_PATCH_PENDING)
a9f3a74a29af09 Thomas Gleixner     2020-07-22  150  			klp_update_patch_state(current);
a9f3a74a29af09 Thomas Gleixner     2020-07-22  151  
12db8b690010cc Jens Axboe          2020-10-26  152  		if (ti_work & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
8ba62d37949e24 Eric W. Biederman   2022-02-09  153  			arch_do_signal_or_restart(regs);
a9f3a74a29af09 Thomas Gleixner     2020-07-22  154  
a68de80f61f6af Sean Christopherson 2021-09-01  155  		if (ti_work & _TIF_NOTIFY_RESUME)
03248addadf1a5 Eric W. Biederman   2022-02-09  156  			resume_user_mode_work(regs);
a9f3a74a29af09 Thomas Gleixner     2020-07-22  157  
a9f3a74a29af09 Thomas Gleixner     2020-07-22  158  		/* Architecture specific TIF work */
a9f3a74a29af09 Thomas Gleixner     2020-07-22  159  		arch_exit_to_user_mode_work(regs, ti_work);
a9f3a74a29af09 Thomas Gleixner     2020-07-22  160  
a9f3a74a29af09 Thomas Gleixner     2020-07-22  161  		/*
a9f3a74a29af09 Thomas Gleixner     2020-07-22  162  		 * Disable interrupts and reevaluate the work flags as they
a9f3a74a29af09 Thomas Gleixner     2020-07-22  163  		 * might have changed while interrupts and preemption was
a9f3a74a29af09 Thomas Gleixner     2020-07-22  164  		 * enabled above.
a9f3a74a29af09 Thomas Gleixner     2020-07-22  165  		 */
a9f3a74a29af09 Thomas Gleixner     2020-07-22  166  		local_irq_disable_exit_to_user();
47b8ff194c1fd7 Frederic Weisbecker 2021-02-01  167  
47b8ff194c1fd7 Frederic Weisbecker 2021-02-01  168  		/* Check if any of the above work has queued a deferred wakeup */
f268c3737ecaef Frederic Weisbecker 2021-05-27  169  		tick_nohz_user_enter_prepare();
47b8ff194c1fd7 Frederic Weisbecker 2021-02-01  170  
6ce895128b3bff Mark Rutland        2021-11-29  171  		ti_work = read_thread_flags();
a9f3a74a29af09 Thomas Gleixner     2020-07-22  172  	}
a9f3a74a29af09 Thomas Gleixner     2020-07-22  173  
a9f3a74a29af09 Thomas Gleixner     2020-07-22  174  	/* Return the latest work state for arch_exit_to_user_mode() */
a9f3a74a29af09 Thomas Gleixner     2020-07-22  175  	return ti_work;
a9f3a74a29af09 Thomas Gleixner     2020-07-22  176  }
a9f3a74a29af09 Thomas Gleixner     2020-07-22  177
diff mbox series

Patch

diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index d95ab85f96ba..b08aceb26e8e 100644
--- 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 +262,42 @@  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
+ *
+ * 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 +316,17 @@  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 d7ee4bc3f2ba..113bd3e8e73e 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -123,29 +123,14 @@  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
+ */
+__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 +175,6 @@  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 +259,7 @@  __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 +272,7 @@  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)