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Subject[PATCH] entry: split lockdep and syscall work functions
Date
On s390, we can not call one function which sets lockdep
state and do the syscall work at the same time. There add
make enter_from_user_mode() and exit_to_user_mode() public, and
add syscall_exit_to_user_mode1() which does the same as
syscall_exit_to_user_mode() but skips the final exit_to_user_mode().

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
---
include/linux/entry-common.h | 4 +++-
kernel/entry/common.c | 35 +++++++++++++++++++++++++++--------
2 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index 474f29638d2c..496c9a47eab4 100644
--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -124,7 +124,7 @@ static inline __must_check int arch_syscall_enter_tracehook(struct pt_regs *regs
* to be done between establishing state and handling user mode entry work.
*/
void syscall_enter_from_user_mode_prepare(struct pt_regs *regs);
-
+void enter_from_user_mode(struct pt_regs *regs);
/**
* syscall_enter_from_user_mode_work - Check and handle work before invoking
* a syscall
@@ -311,6 +311,8 @@ static inline void arch_syscall_exit_tracehook(struct pt_regs *regs, bool step)
* arch_exit_to_user_mode() to handle e.g. speculation mitigations
*/
void syscall_exit_to_user_mode(struct pt_regs *regs);
+void syscall_exit_to_user_mode1(struct pt_regs *regs);
+void exit_to_user_mode(void);

/**
* irqentry_enter_from_user_mode - Establish state before invoking the irq handler
diff --git a/kernel/entry/common.c b/kernel/entry/common.c
index e9e2df3f3f9e..3ad462ebfa15 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -18,7 +18,7 @@
* 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)
+static __always_inline void __enter_from_user_mode(struct pt_regs *regs)
{
arch_check_user_regs(regs);
lockdep_hardirqs_off(CALLER_ADDR0);
@@ -31,6 +31,11 @@ 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())) {
@@ -92,7 +97,7 @@ 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();
@@ -104,14 +109,14 @@ 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();
}

/**
- * exit_to_user_mode - Fixup state when exiting to user mode
+ * __exit_to_user_mode - Fixup state when exiting to user mode
*
* Syscall/interupt exit enables interrupts, but the kernel state is
* interrupts disabled when this is invoked. Also tell RCU about it.
@@ -122,7 +127,7 @@ noinstr void syscall_enter_from_user_mode_prepare(struct pt_regs *regs)
* mitigations, etc.
* 4) Tell lockdep that interrupts are enabled
*/
-static __always_inline void exit_to_user_mode(void)
+static __always_inline void __exit_to_user_mode(void)
{
instrumentation_begin();
trace_hardirqs_on_prepare();
@@ -134,6 +139,11 @@ static __always_inline void exit_to_user_mode(void)
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(struct pt_regs *regs) { }

@@ -265,12 +275,21 @@ __visible noinstr void syscall_exit_to_user_mode(struct pt_regs *regs)
local_irq_disable_exit_to_user();
exit_to_user_mode_prepare(regs);
instrumentation_end();
- exit_to_user_mode();
+ __exit_to_user_mode();
+}
+
+__visible noinstr void syscall_exit_to_user_mode1(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);
+ instrumentation_end();
}

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)
@@ -278,7 +297,7 @@ 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)
--
2.17.1
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