--- zzzz-none-000/linux-3.10.107/arch/tile/kernel/ptrace.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/arch/tile/kernel/ptrace.c	2021-02-04 17:41:59.000000000 +0000
@@ -22,6 +22,7 @@
 #include <linux/regset.h>
 #include <linux/elf.h>
 #include <linux/tracehook.h>
+#include <linux/context_tracking.h>
 #include <asm/traps.h>
 #include <arch/chip.h>
 
@@ -252,12 +253,24 @@
 
 int do_syscall_trace_enter(struct pt_regs *regs)
 {
-	if (test_thread_flag(TIF_SYSCALL_TRACE)) {
+	u32 work = ACCESS_ONCE(current_thread_info()->flags);
+
+	/*
+	 * If TIF_NOHZ is set, we are required to call user_exit() before
+	 * doing anything that could touch RCU.
+	 */
+	if (work & _TIF_NOHZ)
+		user_exit();
+
+	if (secure_computing() == -1)
+		return -1;
+
+	if (work & _TIF_SYSCALL_TRACE) {
 		if (tracehook_report_syscall_entry(regs))
 			regs->regs[TREG_SYSCALL_NR] = -1;
 	}
 
-	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
+	if (work & _TIF_SYSCALL_TRACEPOINT)
 		trace_sys_enter(regs, regs->regs[TREG_SYSCALL_NR]);
 
 	return regs->regs[TREG_SYSCALL_NR];
@@ -265,6 +278,27 @@
 
 void do_syscall_trace_exit(struct pt_regs *regs)
 {
+	long errno;
+
+	/*
+	 * We may come here right after calling schedule_user()
+	 * in which case we can be in RCU user mode.
+	 */
+	user_exit();
+
+	/*
+	 * The standard tile calling convention returns the value (or negative
+	 * errno) in r0, and zero (or positive errno) in r1.
+	 * It saves a couple of cycles on the hot path to do this work in
+	 * registers only as we return, rather than updating the in-memory
+	 * struct ptregs.
+	 */
+	errno = (long) regs->regs[0];
+	if (errno < 0 && errno > -4096)
+		regs->regs[1] = -errno;
+	else
+		regs->regs[1] = 0;
+
 	if (test_thread_flag(TIF_SYSCALL_TRACE))
 		tracehook_report_syscall_exit(regs, 0);
 
@@ -272,7 +306,7 @@
 		trace_sys_exit(regs, regs->regs[0]);
 }
 
-void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code)
+void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs)
 {
 	struct siginfo info;
 
@@ -288,5 +322,7 @@
 /* Handle synthetic interrupt delivered only by the simulator. */
 void __kprobes do_breakpoint(struct pt_regs* regs, int fault_num)
 {
-	send_sigtrap(current, regs, fault_num);
+	enum ctx_state prev_state = exception_enter();
+	send_sigtrap(current, regs);
+	exception_exit(prev_state);
 }