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* [PATCH v2 0/3] entry: inline syscall enter/exit functions
@ 2023-12-18  7:45 Sven Schnelle
  2023-12-18  7:45 ` [PATCH v2 1/3] entry: move exit to usermode functions to header file Sven Schnelle
                   ` (2 more replies)
  0 siblings, 3 replies; 9+ messages in thread
From: Sven Schnelle @ 2023-12-18  7:45 UTC (permalink / raw)
  To: Thomas Gleixner, Peter Zijlstra, Andy Lutomirski
  Cc: linux-kernel, Heiko Carstens

Hi List,

looking into the performance of syscall entry/exit after s390 switched
to generic entry showed that there's quite some overhead calling some
of the entry/exit work functions even when there's nothing to do.
This patchset moves the entry and exit function to entry-common.h, so
non inlined code gets only called when there is some work pending.

I wrote a small program that just issues invalid syscalls in a loop.
On an s390 machine, this results in the following numbers:

without this series:

$ ./syscall 1000000000
runtime: 94.886581s / per-syscall 9.488658e-08s

with this series:

$ ./syscall 1000000000
runtime: 84.732391s / per-syscall 8.473239e-08s

so the time required for one syscall dropped from 94.8ns to
84.7ns, which is a drop of about 11%.

Sven Schnelle (3):
  entry: move exit to usermode functions to header file
  entry: move enter_from_user_mode() to header file
  entry: move syscall_enter_from_user_mode() to header file

 include/linux/entry-common.h |  94 +++++++++++++++++++++++++++++--
 kernel/entry/common.c        | 106 ++++-------------------------------
 2 files changed, 100 insertions(+), 100 deletions(-)

Changes in v2:
- don't move of exit_to_user_mode_loop() to header file
-- 
2.40.1


^ permalink raw reply	[flat|nested] 9+ messages in thread
* [PATCH v2 1/3] entry: move exit to usermode functions to header file
  2023-12-18  7:45 [PATCH v2 0/3] entry: inline syscall enter/exit functions Sven Schnelle
@ 2023-12-18  7:45 ` Sven Schnelle
  2023-12-18 18:31   ` kernel test robot
                     ` (2 more replies)
  2023-12-18  7:45 ` [PATCH v2 2/3] entry: move enter_from_user_mode() " Sven Schnelle
  2023-12-18  7:45 ` [PATCH v2 3/3] entry: move syscall_enter_from_user_mode() " Sven Schnelle
  2 siblings, 3 replies; 9+ messages in thread
From: Sven Schnelle @ 2023-12-18  7:45 UTC (permalink / raw)
  To: Thomas Gleixner, Peter Zijlstra, Andy Lutomirski
  Cc: linux-kernel, Heiko Carstens

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(-)

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)
-- 
2.40.1


^ permalink raw reply	[flat|nested] 9+ messages in thread
* [PATCH v2 2/3] entry: move enter_from_user_mode() to header file
  2023-12-18  7:45 [PATCH v2 0/3] entry: inline syscall enter/exit functions Sven Schnelle
  2023-12-18  7:45 ` [PATCH v2 1/3] entry: move exit to usermode functions to header file Sven Schnelle
@ 2023-12-18  7:45 ` Sven Schnelle
  2023-12-21 22:19   ` [tip: core/entry] entry: Move " tip-bot2 for Sven Schnelle
  2023-12-18  7:45 ` [PATCH v2 3/3] entry: move syscall_enter_from_user_mode() " Sven Schnelle
  2 siblings, 1 reply; 9+ messages in thread
From: Sven Schnelle @ 2023-12-18  7:45 UTC (permalink / raw)
  To: Thomas Gleixner, Peter Zijlstra, Andy Lutomirski
  Cc: linux-kernel, Heiko Carstens

To allow inlining of enter_from_user_mode(), move it to
entry-common.h.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
---
 include/linux/entry-common.h | 15 ++++++++++++++-
 kernel/entry/common.c        | 26 +++-----------------------
 2 files changed, 17 insertions(+), 24 deletions(-)

diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index b08aceb26e8e..e8f1e4bba1c1 100644
--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -11,6 +11,7 @@
 #include <linux/livepatch.h>
 #include <linux/resume_user_mode.h>
 #include <linux/tick.h>
+#include <linux/kmsan.h>
 
 #include <asm/entry-common.h>
 
@@ -102,7 +103,19 @@ static __always_inline void arch_enter_from_user_mode(struct pt_regs *regs) {}
  * done between establishing state and enabling interrupts. The caller must
  * enable interrupts before invoking syscall_enter_from_user_mode_work().
  */
-void enter_from_user_mode(struct pt_regs *regs);
+static __always_inline void enter_from_user_mode(struct pt_regs *regs)
+{
+	arch_enter_from_user_mode(regs);
+	lockdep_hardirqs_off(CALLER_ADDR0);
+
+	CT_WARN_ON(__ct_state() != CONTEXT_USER);
+	user_exit_irqoff();
+
+	instrumentation_begin();
+	kmsan_unpoison_entry_regs(regs);
+	trace_hardirqs_off_finish();
+	instrumentation_end();
+}
 
 /**
  * syscall_enter_from_user_mode_prepare - Establish state and enable interrupts
diff --git a/kernel/entry/common.c b/kernel/entry/common.c
index 113bd3e8e73e..cd40cd1b4616 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -15,26 +15,6 @@
 #define CREATE_TRACE_POINTS
 #include <trace/events/syscalls.h>
 
-/* See comment for enter_from_user_mode() in entry-common.h */
-static __always_inline void __enter_from_user_mode(struct pt_regs *regs)
-{
-	arch_enter_from_user_mode(regs);
-	lockdep_hardirqs_off(CALLER_ADDR0);
-
-	CT_WARN_ON(__ct_state() != CONTEXT_USER);
-	user_exit_irqoff();
-
-	instrumentation_begin();
-	kmsan_unpoison_entry_regs(regs);
-	trace_hardirqs_off_finish();
-	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())) {
@@ -105,7 +85,7 @@ noinstr long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall)
 {
 	long ret;
 
-	__enter_from_user_mode(regs);
+	enter_from_user_mode(regs);
 
 	instrumentation_begin();
 	local_irq_enable();
@@ -117,7 +97,7 @@ noinstr long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall)
 
 noinstr void syscall_enter_from_user_mode_prepare(struct pt_regs *regs)
 {
-	__enter_from_user_mode(regs);
+	enter_from_user_mode(regs);
 	instrumentation_begin();
 	local_irq_enable();
 	instrumentation_end();
@@ -264,7 +244,7 @@ __visible noinstr void syscall_exit_to_user_mode(struct pt_regs *regs)
 
 noinstr void irqentry_enter_from_user_mode(struct pt_regs *regs)
 {
-	__enter_from_user_mode(regs);
+	enter_from_user_mode(regs);
 }
 
 noinstr void irqentry_exit_to_user_mode(struct pt_regs *regs)
-- 
2.40.1


^ permalink raw reply	[flat|nested] 9+ messages in thread
* [PATCH v2 3/3] entry: move syscall_enter_from_user_mode() to header file
  2023-12-18  7:45 [PATCH v2 0/3] entry: inline syscall enter/exit functions Sven Schnelle
  2023-12-18  7:45 ` [PATCH v2 1/3] entry: move exit to usermode functions to header file Sven Schnelle
  2023-12-18  7:45 ` [PATCH v2 2/3] entry: move enter_from_user_mode() " Sven Schnelle
@ 2023-12-18  7:45 ` Sven Schnelle
  2023-12-21 22:19   ` [tip: core/entry] entry: Move " tip-bot2 for Sven Schnelle
  2 siblings, 1 reply; 9+ messages in thread
From: Sven Schnelle @ 2023-12-18  7:45 UTC (permalink / raw)
  To: Thomas Gleixner, Peter Zijlstra, Andy Lutomirski
  Cc: linux-kernel, Heiko Carstens

To allow inlining of syscall_enter_from_user_mode(), move it
to entry-common.h.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
---
 include/linux/entry-common.h | 27 +++++++++++++++++++++++++--
 kernel/entry/common.c        | 32 +-------------------------------
 2 files changed, 26 insertions(+), 33 deletions(-)

diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index e8f1e4bba1c1..4f8e467eaf3c 100644
--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -134,6 +134,9 @@ static __always_inline void enter_from_user_mode(struct pt_regs *regs)
  */
 void syscall_enter_from_user_mode_prepare(struct pt_regs *regs);
 
+long syscall_trace_enter(struct pt_regs *regs, long syscall,
+			 unsigned long work);
+
 /**
  * syscall_enter_from_user_mode_work - Check and handle work before invoking
  *				       a syscall
@@ -157,7 +160,15 @@ void syscall_enter_from_user_mode_prepare(struct pt_regs *regs);
  *     ptrace_report_syscall_entry(), __secure_computing(), trace_sys_enter()
  *  2) Invocation of audit_syscall_entry()
  */
-long syscall_enter_from_user_mode_work(struct pt_regs *regs, long syscall);
+static __always_inline long syscall_enter_from_user_mode_work(struct pt_regs *regs, long syscall)
+{
+	unsigned long work = READ_ONCE(current_thread_info()->syscall_work);
+
+	if (work & SYSCALL_WORK_ENTER)
+		syscall = syscall_trace_enter(regs, syscall, work);
+
+	return syscall;
+}
 
 /**
  * syscall_enter_from_user_mode - Establish state and check and handle work
@@ -176,7 +187,19 @@ long syscall_enter_from_user_mode_work(struct pt_regs *regs, long syscall);
  * Returns: The original or a modified syscall number. See
  * syscall_enter_from_user_mode_work() for further explanation.
  */
-long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall);
+static __always_inline long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall)
+{
+	long ret;
+
+	enter_from_user_mode(regs);
+
+	instrumentation_begin();
+	local_irq_enable();
+	ret = syscall_enter_from_user_mode_work(regs, syscall);
+	instrumentation_end();
+
+	return ret;
+}
 
 /**
  * local_irq_enable_exit_to_user - Exit to user variant of local_irq_enable()
diff --git a/kernel/entry/common.c b/kernel/entry/common.c
index cd40cd1b4616..a35aaaa9f8bc 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -25,7 +25,7 @@ static inline void syscall_enter_audit(struct pt_regs *regs, long syscall)
 	}
 }
 
-static long syscall_trace_enter(struct pt_regs *regs, long syscall,
+long syscall_trace_enter(struct pt_regs *regs, long syscall,
 				unsigned long work)
 {
 	long ret = 0;
@@ -65,36 +65,6 @@ static long syscall_trace_enter(struct pt_regs *regs, long syscall,
 	return ret ? : syscall;
 }
 
-static __always_inline long
-__syscall_enter_from_user_work(struct pt_regs *regs, long syscall)
-{
-	unsigned long work = READ_ONCE(current_thread_info()->syscall_work);
-
-	if (work & SYSCALL_WORK_ENTER)
-		syscall = syscall_trace_enter(regs, syscall, work);
-
-	return syscall;
-}
-
-long syscall_enter_from_user_mode_work(struct pt_regs *regs, long syscall)
-{
-	return __syscall_enter_from_user_work(regs, syscall);
-}
-
-noinstr long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall)
-{
-	long ret;
-
-	enter_from_user_mode(regs);
-
-	instrumentation_begin();
-	local_irq_enable();
-	ret = __syscall_enter_from_user_work(regs, syscall);
-	instrumentation_end();
-
-	return ret;
-}
-
 noinstr void syscall_enter_from_user_mode_prepare(struct pt_regs *regs)
 {
 	enter_from_user_mode(regs);
-- 
2.40.1


^ permalink raw reply	[flat|nested] 9+ messages in thread
* Re: [PATCH v2 1/3] entry: move exit to usermode functions to header file
  2023-12-18  7:45 ` [PATCH v2 1/3] entry: move exit to usermode functions to header file Sven Schnelle
@ 2023-12-18 18:31   ` kernel test robot
  2023-12-20 21:35   ` kernel test robot
  2023-12-21 22:19   ` [tip: core/entry] entry: Move " tip-bot2 for Sven Schnelle
  2 siblings, 0 replies; 9+ messages in thread
From: kernel test robot @ 2023-12-18 18:31 UTC (permalink / raw)
  To: Sven Schnelle, Thomas Gleixner, Peter Zijlstra, Andy Lutomirski
  Cc: oe-kbuild-all, linux-kernel, Heiko Carstens

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  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

^ permalink raw reply	[flat|nested] 9+ messages in thread
* Re: [PATCH v2 1/3] entry: move exit to usermode functions to header file
  2023-12-18  7:45 ` [PATCH v2 1/3] entry: move exit to usermode functions to header file Sven Schnelle
  2023-12-18 18:31   ` kernel test robot
@ 2023-12-20 21:35   ` kernel test robot
  2023-12-21 22:19   ` [tip: core/entry] entry: Move " tip-bot2 for Sven Schnelle
  2 siblings, 0 replies; 9+ messages in thread
From: kernel test robot @ 2023-12-20 21:35 UTC (permalink / raw)
  To: Sven Schnelle, Thomas Gleixner, Peter Zijlstra, Andy Lutomirski
  Cc: oe-kbuild-all, linux-kernel, Heiko Carstens

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  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

^ permalink raw reply	[flat|nested] 9+ messages in thread
* [tip: core/entry] entry: Move syscall_enter_from_user_mode() to header file
  2023-12-18  7:45 ` [PATCH v2 3/3] entry: move syscall_enter_from_user_mode() " Sven Schnelle
@ 2023-12-21 22:19   ` tip-bot2 for Sven Schnelle
  0 siblings, 0 replies; 9+ messages in thread
From: tip-bot2 for Sven Schnelle @ 2023-12-21 22:19 UTC (permalink / raw)
  To: linux-tip-commits; +Cc: Sven Schnelle, Thomas Gleixner, x86, linux-kernel

The following commit has been merged into the core/entry branch of tip:

Commit-ID:     221a164035fd8b554a44bd7c4bf8e7715a497561
Gitweb:        https://git.kernel.org/tip/221a164035fd8b554a44bd7c4bf8e7715a497561
Author:        Sven Schnelle <svens@linux.ibm.com>
AuthorDate:    Mon, 18 Dec 2023 08:45:20 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Thu, 21 Dec 2023 23:12:18 +01:00

entry: Move syscall_enter_from_user_mode() to header file

To allow inlining of syscall_enter_from_user_mode(), move it
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/20231218074520.1998026-4-svens@linux.ibm.com

---
 include/linux/entry-common.h | 27 +++++++++++++++++++++++++--
 kernel/entry/common.c        | 32 +-------------------------------
 2 files changed, 26 insertions(+), 33 deletions(-)

diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index c420539..b0fb775 100644
--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -134,6 +134,9 @@ static __always_inline void enter_from_user_mode(struct pt_regs *regs)
  */
 void syscall_enter_from_user_mode_prepare(struct pt_regs *regs);
 
+long syscall_trace_enter(struct pt_regs *regs, long syscall,
+			 unsigned long work);
+
 /**
  * syscall_enter_from_user_mode_work - Check and handle work before invoking
  *				       a syscall
@@ -157,7 +160,15 @@ void syscall_enter_from_user_mode_prepare(struct pt_regs *regs);
  *     ptrace_report_syscall_entry(), __secure_computing(), trace_sys_enter()
  *  2) Invocation of audit_syscall_entry()
  */
-long syscall_enter_from_user_mode_work(struct pt_regs *regs, long syscall);
+static __always_inline long syscall_enter_from_user_mode_work(struct pt_regs *regs, long syscall)
+{
+	unsigned long work = READ_ONCE(current_thread_info()->syscall_work);
+
+	if (work & SYSCALL_WORK_ENTER)
+		syscall = syscall_trace_enter(regs, syscall, work);
+
+	return syscall;
+}
 
 /**
  * syscall_enter_from_user_mode - Establish state and check and handle work
@@ -176,7 +187,19 @@ long syscall_enter_from_user_mode_work(struct pt_regs *regs, long syscall);
  * Returns: The original or a modified syscall number. See
  * syscall_enter_from_user_mode_work() for further explanation.
  */
-long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall);
+static __always_inline long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall)
+{
+	long ret;
+
+	enter_from_user_mode(regs);
+
+	instrumentation_begin();
+	local_irq_enable();
+	ret = syscall_enter_from_user_mode_work(regs, syscall);
+	instrumentation_end();
+
+	return ret;
+}
 
 /**
  * local_irq_enable_exit_to_user - Exit to user variant of local_irq_enable()
diff --git a/kernel/entry/common.c b/kernel/entry/common.c
index 0616f23..88cb3c8 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -25,7 +25,7 @@ static inline void syscall_enter_audit(struct pt_regs *regs, long syscall)
 	}
 }
 
-static long syscall_trace_enter(struct pt_regs *regs, long syscall,
+long syscall_trace_enter(struct pt_regs *regs, long syscall,
 				unsigned long work)
 {
 	long ret = 0;
@@ -65,36 +65,6 @@ static long syscall_trace_enter(struct pt_regs *regs, long syscall,
 	return ret ? : syscall;
 }
 
-static __always_inline long
-__syscall_enter_from_user_work(struct pt_regs *regs, long syscall)
-{
-	unsigned long work = READ_ONCE(current_thread_info()->syscall_work);
-
-	if (work & SYSCALL_WORK_ENTER)
-		syscall = syscall_trace_enter(regs, syscall, work);
-
-	return syscall;
-}
-
-long syscall_enter_from_user_mode_work(struct pt_regs *regs, long syscall)
-{
-	return __syscall_enter_from_user_work(regs, syscall);
-}
-
-noinstr long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall)
-{
-	long ret;
-
-	enter_from_user_mode(regs);
-
-	instrumentation_begin();
-	local_irq_enable();
-	ret = __syscall_enter_from_user_work(regs, syscall);
-	instrumentation_end();
-
-	return ret;
-}
-
 noinstr void syscall_enter_from_user_mode_prepare(struct pt_regs *regs)
 {
 	enter_from_user_mode(regs);

^ permalink raw reply	[flat|nested] 9+ messages in thread
* [tip: core/entry] entry: Move enter_from_user_mode() to header file
  2023-12-18  7:45 ` [PATCH v2 2/3] entry: move enter_from_user_mode() " Sven Schnelle
@ 2023-12-21 22:19   ` tip-bot2 for Sven Schnelle
  0 siblings, 0 replies; 9+ messages in thread
From: tip-bot2 for Sven Schnelle @ 2023-12-21 22:19 UTC (permalink / raw)
  To: linux-tip-commits; +Cc: Sven Schnelle, Thomas Gleixner, x86, linux-kernel

The following commit has been merged into the core/entry branch of tip:

Commit-ID:     caf4062e35b21cd7d3d35ac2f58f9765d02d32a0
Gitweb:        https://git.kernel.org/tip/caf4062e35b21cd7d3d35ac2f58f9765d02d32a0
Author:        Sven Schnelle <svens@linux.ibm.com>
AuthorDate:    Mon, 18 Dec 2023 08:45:19 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Thu, 21 Dec 2023 23:12:18 +01:00

entry: Move enter_from_user_mode() to header file

To allow inlining of enter_from_user_mode(), move it 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/20231218074520.1998026-3-svens@linux.ibm.com

---
 include/linux/entry-common.h | 15 ++++++++++++++-
 kernel/entry/common.c        | 26 +++-----------------------
 2 files changed, 17 insertions(+), 24 deletions(-)

diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index 6a6e98f..c420539 100644
--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -11,6 +11,7 @@
 #include <linux/livepatch.h>
 #include <linux/resume_user_mode.h>
 #include <linux/tick.h>
+#include <linux/kmsan.h>
 
 #include <asm/entry-common.h>
 
@@ -102,7 +103,19 @@ static __always_inline void arch_enter_from_user_mode(struct pt_regs *regs) {}
  * done between establishing state and enabling interrupts. The caller must
  * enable interrupts before invoking syscall_enter_from_user_mode_work().
  */
-void enter_from_user_mode(struct pt_regs *regs);
+static __always_inline void enter_from_user_mode(struct pt_regs *regs)
+{
+	arch_enter_from_user_mode(regs);
+	lockdep_hardirqs_off(CALLER_ADDR0);
+
+	CT_WARN_ON(__ct_state() != CONTEXT_USER);
+	user_exit_irqoff();
+
+	instrumentation_begin();
+	kmsan_unpoison_entry_regs(regs);
+	trace_hardirqs_off_finish();
+	instrumentation_end();
+}
 
 /**
  * syscall_enter_from_user_mode_prepare - Establish state and enable interrupts
diff --git a/kernel/entry/common.c b/kernel/entry/common.c
index 7f8f8c1..0616f23 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -15,26 +15,6 @@
 #define CREATE_TRACE_POINTS
 #include <trace/events/syscalls.h>
 
-/* See comment for enter_from_user_mode() in entry-common.h */
-static __always_inline void __enter_from_user_mode(struct pt_regs *regs)
-{
-	arch_enter_from_user_mode(regs);
-	lockdep_hardirqs_off(CALLER_ADDR0);
-
-	CT_WARN_ON(__ct_state() != CONTEXT_USER);
-	user_exit_irqoff();
-
-	instrumentation_begin();
-	kmsan_unpoison_entry_regs(regs);
-	trace_hardirqs_off_finish();
-	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())) {
@@ -105,7 +85,7 @@ noinstr long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall)
 {
 	long ret;
 
-	__enter_from_user_mode(regs);
+	enter_from_user_mode(regs);
 
 	instrumentation_begin();
 	local_irq_enable();
@@ -117,7 +97,7 @@ noinstr long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall)
 
 noinstr void syscall_enter_from_user_mode_prepare(struct pt_regs *regs)
 {
-	__enter_from_user_mode(regs);
+	enter_from_user_mode(regs);
 	instrumentation_begin();
 	local_irq_enable();
 	instrumentation_end();
@@ -266,7 +246,7 @@ __visible noinstr void syscall_exit_to_user_mode(struct pt_regs *regs)
 
 noinstr void irqentry_enter_from_user_mode(struct pt_regs *regs)
 {
-	__enter_from_user_mode(regs);
+	enter_from_user_mode(regs);
 }
 
 noinstr void irqentry_exit_to_user_mode(struct pt_regs *regs)

^ permalink raw reply	[flat|nested] 9+ messages in thread
* [tip: core/entry] entry: Move exit to usermode functions to header file
  2023-12-18  7:45 ` [PATCH v2 1/3] entry: move exit to usermode functions to header file Sven Schnelle
  2023-12-18 18:31   ` kernel test robot
  2023-12-20 21:35   ` kernel test robot
@ 2023-12-21 22:19   ` tip-bot2 for Sven Schnelle
  2 siblings, 0 replies; 9+ messages in thread
From: tip-bot2 for Sven Schnelle @ 2023-12-21 22:19 UTC (permalink / raw)
  To: linux-tip-commits; +Cc: Sven Schnelle, Thomas Gleixner, x86, linux-kernel

The following commit has been merged into the core/entry branch of tip:

Commit-ID:     d68019471995ba47e56a9da355df13a1cdb5bf7e
Gitweb:        https://git.kernel.org/tip/d68019471995ba47e56a9da355df13a1cdb5bf7e
Author:        Sven Schnelle <svens@linux.ibm.com>
AuthorDate:    Mon, 18 Dec 2023 08:45:18 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Thu, 21 Dec 2023 23:12:18 +01:00

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

---
 include/linux/entry-common.h | 53 ++++++++++++++++++++++++++++++++++-
 kernel/entry/common.c        | 52 +++++-----------------------------
 2 files changed, 61 insertions(+), 44 deletions(-)

diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index d95ab85..6a6e98f 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>
 
@@ -259,6 +263,43 @@ 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
  *
  * Syscall/interrupt exit enables interrupts, but the kernel state is
@@ -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 d7ee4bc..7f8f8c1 100644
--- 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)

^ permalink raw reply	[flat|nested] 9+ messages in thread
end of thread, other threads:[~2023-12-21 22:19 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-12-18  7:45 [PATCH v2 0/3] entry: inline syscall enter/exit functions Sven Schnelle
2023-12-18  7:45 ` [PATCH v2 1/3] entry: move exit to usermode functions to header file Sven Schnelle
2023-12-18 18:31   ` kernel test robot
2023-12-20 21:35   ` kernel test robot
2023-12-21 22:19   ` [tip: core/entry] entry: Move " tip-bot2 for Sven Schnelle
2023-12-18  7:45 ` [PATCH v2 2/3] entry: move enter_from_user_mode() " Sven Schnelle
2023-12-21 22:19   ` [tip: core/entry] entry: Move " tip-bot2 for Sven Schnelle
2023-12-18  7:45 ` [PATCH v2 3/3] entry: move syscall_enter_from_user_mode() " Sven Schnelle
2023-12-21 22:19   ` [tip: core/entry] entry: Move " tip-bot2 for Sven Schnelle

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