[patch 14/18] entry: Make return type of syscall_trace_enter() bool

[Thomas Gleixner]

This prepares for changing the return types of
syscall_enter_from_user_mode[_work]() to bool, which in turn separates the
decision of invoking the syscall from the syscall number, which might have
been changed in the call by ptrace, seccomp, tracing.

Signed-off-by: Thomas Gleixner <tglx at kernel.org>
---
 include/linux/entry-common.h |   28 +++++++++++++++-------------
 1 file changed, 15 insertions(+), 13 deletions(-)

--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -71,8 +71,8 @@ static inline void syscall_enter_audit(s
 	}
 }
 
-static __always_inline long syscall_trace_enter(struct pt_regs *regs, unsigned long work,
-						long syscall)
+static __always_inline bool syscall_trace_enter(struct pt_regs *regs, unsigned long work,
+						long *syscall)
 {
 	/*
 	 * Handle Syscall User Dispatch.  This must comes first, since
@@ -81,7 +81,7 @@ static __always_inline long syscall_trac
 	 */
 	if (work & SYSCALL_WORK_SYSCALL_USER_DISPATCH) {
 		if (syscall_user_dispatch(regs))
-			return -1L;
+			return false;
 	}
 
 	/*
@@ -90,32 +90,32 @@ static __always_inline long syscall_trac
 	 * through hrtimer_interrupt().
 	 */
 	if (work & SYSCALL_WORK_SYSCALL_RSEQ_SLICE)
-		rseq_syscall_enter_work(syscall);
+		rseq_syscall_enter_work(*syscall);
 
 	/* Handle ptrace */
 	if (work & (SYSCALL_WORK_SYSCALL_TRACE | SYSCALL_WORK_SYSCALL_EMU)) {
 		if (!arch_ptrace_report_syscall_permit_entry(regs) ||
 		    (work & SYSCALL_WORK_SYSCALL_EMU))
-			return -1L;
+			return false;
 	}
 
 	/* Do seccomp after ptrace, to catch any tracer changes. */
 	if (work & SYSCALL_WORK_SECCOMP) {
 		if (!__seccomp_permit_syscall())
-			return -1L;
+			return false;
 	}
 
 	/* Either of the above might have changed the syscall number */
-	syscall = syscall_get_nr(current, regs);
+	*syscall = syscall_get_nr(current, regs);
 
 	if (unlikely(work & SYSCALL_WORK_SYSCALL_TRACEPOINT)) {
-		if (!trace_syscall_enter(regs, &syscall))
-			return -1L;
+		if (!trace_syscall_enter(regs, syscall))
+			return false;
 	}
 
-	syscall_enter_audit(regs, syscall);
+	syscall_enter_audit(regs, *syscall);
 
-	return syscall;
+	return true;
 }
 
 /**
@@ -145,8 +145,10 @@ static __always_inline long syscall_ente
 {
 	unsigned long work = READ_ONCE(current_thread_info()->syscall_work);
 
-	if (work & SYSCALL_WORK_ENTER)
-		syscall = syscall_trace_enter(regs, work, syscall);
+	if (work & SYSCALL_WORK_ENTER) {
+		if (!syscall_trace_enter(regs, work, &syscall))
+			return -1L;
+	}
 
 	return syscall;
 }