Now that we have a new hook ptrace_syscall_enter that can be called from
syscall entry code and it handles PTRACE_SYSEMU in generic code, we
can do some cleanup using the same in syscall_trace_enter.

Further the extra logic to find single stepping PTRACE_SYSEMU_SINGLESTEP
in syscall_slow_exit_work seems unnecessary. Let's remove the same.

Cc: Andy Lutomirski <l...@kernel.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Ingo Molnar <mi...@redhat.com>
Cc: Borislav Petkov <b...@alien8.de>
Signed-off-by: Sudeep Holla <sudeep.ho...@arm.com>
---
 arch/x86/entry/common.c | 22 ++++------------------
 1 file changed, 4 insertions(+), 18 deletions(-)

diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 7bc105f47d21..36457c1f87d2 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -70,22 +70,16 @@ static long syscall_trace_enter(struct pt_regs *regs)
 
        struct thread_info *ti = current_thread_info();
        unsigned long ret = 0;
-       bool emulated = false;
        u32 work;
 
        if (IS_ENABLED(CONFIG_DEBUG_ENTRY))
                BUG_ON(regs != task_pt_regs(current));
 
-       work = READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY;
-
-       if (unlikely(work & _TIF_SYSCALL_EMU))
-               emulated = true;
-
-       if ((emulated || (work & _TIF_SYSCALL_TRACE)) &&
-           tracehook_report_syscall_entry(regs))
+       if (unlikely(ptrace_syscall_enter(regs)))
                return -1L;
 
-       if (emulated)
+       work = READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY;
+       if ((work & _TIF_SYSCALL_TRACE) && tracehook_report_syscall_entry(regs))
                return -1L;
 
 #ifdef CONFIG_SECCOMP
@@ -227,15 +221,7 @@ static void syscall_slow_exit_work(struct pt_regs *regs, 
u32 cached_flags)
        if (cached_flags & _TIF_SYSCALL_TRACEPOINT)
                trace_sys_exit(regs, regs->ax);
 
-       /*
-        * If TIF_SYSCALL_EMU is set, we only get here because of
-        * TIF_SINGLESTEP (i.e. this is PTRACE_SYSEMU_SINGLESTEP).
-        * We already reported this syscall instruction in
-        * syscall_trace_enter().
-        */
-       step = unlikely(
-               (cached_flags & (_TIF_SINGLESTEP | _TIF_SYSCALL_EMU))
-               == _TIF_SINGLESTEP);
+       step = unlikely((cached_flags & _TIF_SINGLESTEP));
        if (step || cached_flags & _TIF_SYSCALL_TRACE)
                tracehook_report_syscall_exit(regs, step);
 }
-- 
2.17.1

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