From: Sudeep Holla <sudeep.holla@arm.com>
Date: Tue, 11 Jun 2019 14:56:27 +0000 (+0100)
Subject: x86/entry: Simplify _TIF_SYSCALL_EMU handling
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=b07d7d5c7b421462dc91f0b775e31aae49804050;p=openwrt%2Fstaging%2Fblogic.git

x86/entry: Simplify _TIF_SYSCALL_EMU handling

The usage of emulated and _TIF_SYSCALL_EMU flags in syscall_trace_enter
is more complicated than required.

Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---

diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index a986b3c8294c..0a61705d62ec 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -72,23 +72,18 @@ 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;
+	work = READ_ONCE(ti->flags);
 
-	if (unlikely(work & _TIF_SYSCALL_EMU))
-		emulated = true;
-
-	if ((emulated || (work & _TIF_SYSCALL_TRACE)) &&
-	    tracehook_report_syscall_entry(regs))
-		return -1L;
-
-	if (emulated)
-		return -1L;
+	if (work & (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU)) {
+		ret = tracehook_report_syscall_entry(regs);
+		if (ret || (work & _TIF_SYSCALL_EMU))
+			return -1L;
+	}
 
 #ifdef CONFIG_SECCOMP
 	/*