Currently syscall_trace() is called only for ptrace.
With additional TIF_xx flags introduced, it is now called in all the cases
of audit, ftrace and seccomp in addition to ptrace.
Those features will be implemented later, but it's safe to include them
now because they can not be turned on anyway.

Signed-off-by: AKASHI Takahiro <redacted>
---
 arch/arm64/include/asm/thread_info.h |   13 +++++++++++++
 arch/arm64/kernel/entry.S            |    5 +++--
 arch/arm64/kernel/ptrace.c           |   11 +++++------
 3 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index 720e70b..c3df797 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h

 #endif /* __KERNEL__ */
 #endif /* __ASM_THREAD_INFO_H */

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 39ac630..c94b2ab 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S

@@ -631,8 +631,9 @@ el0_svc_naked:					// compat entry point
 	enable_irq
 
 	get_thread_info tsk
-	ldr	x16, [tsk, #TI_FLAGS]		// check for syscall tracing
-	tbnz	x16, #TIF_SYSCALL_TRACE, __sys_trace // are we tracing syscalls?
+	ldr	x16, [tsk, #TI_FLAGS]		// check for syscall hooks
+	tst	x16, #_TIF_WORK_SYSCALL
+	b.ne	__sys_trace
 	adr	lr, ret_fast_syscall		// return address
 	cmp     scno, sc_nr                     // check upper syscall limit
 	b.hs	ni_sys

diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index 6a8928b..64ce39f 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c

@@ -1062,9 +1062,6 @@ asmlinkage int syscall_trace(int dir, struct pt_regs *regs)
 {
 	unsigned long saved_reg;
 
-	if (!test_thread_flag(TIF_SYSCALL_TRACE))
-		return regs->syscallno;

 	if (is_compat_task()) {
 		/* AArch32 uses ip (r12) for scratch */
 		saved_reg = regs->regs[12];

@@ -1078,10 +1075,12 @@ asmlinkage int syscall_trace(int dir, struct pt_regs *regs)
 		regs->regs[7] = dir;
 	}
 
-	if (dir)
+	if (dir) {
 		tracehook_report_syscall_exit(regs, 0);
-	else if (tracehook_report_syscall_entry(regs))
-		regs->syscallno = ~0UL;
+	} else {
+		if (tracehook_report_syscall_entry(regs))
+			regs->syscallno = ~0UL;
+	}