[PATCH 2/2] entry: move the enter path to header files

Sven Schnelle
2023-05-16T13:40:11Z

In order to allow inlining the generic entry C functions,
move them to include/linux/entry-common.h.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
---
include/linux/entry-common.h | 123 +++++++++++++++++++++++++++++++++--
kernel/entry/common.c | 113 --------------------------------
2 files changed, 118 insertions(+), 118 deletions(-)

diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index b409fbcbd3ac..cada155bf316 100644
--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -15,6 +15,8 @@

#include <trace/events/syscalls.h>

+bool syscall_user_dispatch(struct pt_regs *regs);
+
/*
* Define dummy _TIF work flags if not defined by the architecture or for
* disabled functionality.
@@ -103,7 +105,7 @@ 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 void enter_from_user_mode(struct pt_regs *regs);

/**
* syscall_enter_from_user_mode_prepare - Establish state and enable interrupts
@@ -120,7 +122,7 @@ void enter_from_user_mode(struct pt_regs *regs);
* This is invoked when there is extra architecture specific functionality
* to be done between establishing state and handling user mode entry work.
*/
-void syscall_enter_from_user_mode_prepare(struct pt_regs *regs);
+static void syscall_enter_from_user_mode_prepare(struct pt_regs *regs);

/**
* syscall_enter_from_user_mode_work - Check and handle work before invoking
@@ -145,7 +147,7 @@ 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 long syscall_enter_from_user_mode_work(struct pt_regs *regs, long syscall);

/**
* syscall_enter_from_user_mode - Establish state and check and handle work
@@ -164,7 +166,7 @@ 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 long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall);

/**
* local_irq_enable_exit_to_user - Exit to user variant of local_irq_enable()
@@ -281,7 +283,7 @@ 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 void exit_to_user_mode(void);

/**
* syscall_exit_to_user_mode_work - Handle work before returning to user mode
@@ -640,5 +642,116 @@ static __always_inline void irqentry_exit_to_user_mode(struct pt_regs *regs)
__exit_to_user_mode();
}

+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();
+}
+
+static __always_inline void enter_from_user_mode(struct pt_regs *regs)
+{
+ __enter_from_user_mode(regs);
+}
+
+static __always_inline void exit_to_user_mode(void)
+{
+ __exit_to_user_mode();
+}
+
+static inline __always_inline void syscall_enter_audit(struct pt_regs *regs, long syscall)
+{
+ if (unlikely(audit_context())) {
+ unsigned long args[6];
+
+ syscall_get_arguments(current, regs, args);
+ audit_syscall_entry(syscall, args[0], args[1], args[2], args[3]);
+ }
+}
+
+static __always_inline long syscall_trace_enter(struct pt_regs *regs, long syscall,
+ unsigned long work)
+{
+ long ret = 0;
+
+ /*
+ * Handle Syscall User Dispatch. This must comes first, since
+ * the ABI here can be something that doesn't make sense for
+ * other syscall_work features.
+ */
+ if (work & SYSCALL_WORK_SYSCALL_USER_DISPATCH) {
+ if (syscall_user_dispatch(regs))
+ return -1L;
+ }
+
+ /* Handle ptrace */
+ if (work & (SYSCALL_WORK_SYSCALL_TRACE | SYSCALL_WORK_SYSCALL_EMU)) {
+ ret = ptrace_report_syscall_entry(regs);
+ if (ret || (work & SYSCALL_WORK_SYSCALL_EMU))
+ return -1L;
+ }
+
+ /* Do seccomp after ptrace, to catch any tracer changes. */
+ if (work & SYSCALL_WORK_SECCOMP) {
+ ret = __secure_computing(NULL);
+ if (ret == -1L)
+ return ret;
+ }
+
+ /* Either of the above might have changed the syscall number */
+ syscall = syscall_get_nr(current, regs);
+
+ if (unlikely(work & SYSCALL_WORK_SYSCALL_TRACEPOINT))
+ trace_sys_enter(regs, syscall);
+
+ syscall_enter_audit(regs, 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;
+}
+
+static __always_inline long syscall_enter_from_user_mode_work(struct pt_regs *regs, long syscall)
+{
+ return __syscall_enter_from_user_work(regs, 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_work(regs, syscall);
+ instrumentation_end();
+
+ return ret;
+}
+
+static __always_inline void syscall_enter_from_user_mode_prepare(struct pt_regs *regs)
+{
+ __enter_from_user_mode(regs);
+ instrumentation_begin();
+ local_irq_enable();
+ instrumentation_end();
+}

#endif
diff --git a/kernel/entry/common.c b/kernel/entry/common.c
index 66af971c3fe4..3bd528bb5d47 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -15,119 +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())) {
- unsigned long args[6];
-
- syscall_get_arguments(current, regs, args);
- audit_syscall_entry(syscall, args[0], args[1], args[2], args[3]);
- }
-}
-
-static long syscall_trace_enter(struct pt_regs *regs, long syscall,
- unsigned long work)
-{
- long ret = 0;
-
- /*
- * Handle Syscall User Dispatch. This must comes first, since
- * the ABI here can be something that doesn't make sense for
- * other syscall_work features.
- */
- if (work & SYSCALL_WORK_SYSCALL_USER_DISPATCH) {
- if (syscall_user_dispatch(regs))
- return -1L;
- }
-
- /* Handle ptrace */
- if (work & (SYSCALL_WORK_SYSCALL_TRACE | SYSCALL_WORK_SYSCALL_EMU)) {
- ret = ptrace_report_syscall_entry(regs);
- if (ret || (work & SYSCALL_WORK_SYSCALL_EMU))
- return -1L;
- }
-
- /* Do seccomp after ptrace, to catch any tracer changes. */
- if (work & SYSCALL_WORK_SECCOMP) {
- ret = __secure_computing(NULL);
- if (ret == -1L)
- return ret;
- }
-
- /* Either of the above might have changed the syscall number */
- syscall = syscall_get_nr(current, regs);
-
- if (unlikely(work & SYSCALL_WORK_SYSCALL_TRACEPOINT))
- trace_sys_enter(regs, syscall);
-
- syscall_enter_audit(regs, 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);
- instrumentation_begin();
- local_irq_enable();
- instrumentation_end();
-}
-
-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) { }

--
2.39.2