MIPS: ftrace: Add support for syscall tracepoints.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/include/asm/syscall.h b/arch/mips/include/asm/syscall.h
index 087df5f..81c8913 100644
--- a/arch/mips/include/asm/syscall.h
+++ b/arch/mips/include/asm/syscall.h
@@ -59,6 +59,25 @@
 	}
 }
 
+static inline long syscall_get_return_value(struct task_struct *task,
+					    struct pt_regs *regs)
+{
+	return regs->regs[2];
+}
+
+static inline void syscall_set_return_value(struct task_struct *task,
+					    struct pt_regs *regs,
+					    int error, long val)
+{
+	if (error) {
+		regs->regs[2] = -error;
+		regs->regs[7] = -1;
+	} else {
+		regs->regs[2] = val;
+		regs->regs[7] = 0;
+	}
+}
+
 static inline void syscall_get_arguments(struct task_struct *task,
 					 struct pt_regs *regs,
 					 unsigned int i, unsigned int n,
diff --git a/arch/mips/include/asm/thread_info.h b/arch/mips/include/asm/thread_info.h
index e0c8cf3..f9b24bf 100644
--- a/arch/mips/include/asm/thread_info.h
+++ b/arch/mips/include/asm/thread_info.h
@@ -116,6 +116,7 @@
 #define TIF_32BIT_ADDR		23	/* 32-bit address space (o32/n32) */
 #define TIF_FPUBOUND		24	/* thread bound to FPU-full CPU set */
 #define TIF_LOAD_WATCH		25	/* If set, load watch registers */
+#define TIF_SYSCALL_TRACEPOINT	26	/* syscall tracepoint instrumentation */
 #define TIF_SYSCALL_TRACE	31	/* syscall trace active */
 
 #define _TIF_SYSCALL_TRACE	(1<<TIF_SYSCALL_TRACE)
@@ -132,20 +133,22 @@
 #define _TIF_32BIT_ADDR		(1<<TIF_32BIT_ADDR)
 #define _TIF_FPUBOUND		(1<<TIF_FPUBOUND)
 #define _TIF_LOAD_WATCH		(1<<TIF_LOAD_WATCH)
+#define _TIF_SYSCALL_TRACEPOINT	(1<<TIF_SYSCALL_TRACEPOINT)
 
 #define _TIF_WORK_SYSCALL_ENTRY	(_TIF_NOHZ | _TIF_SYSCALL_TRACE |	\
-				 _TIF_SYSCALL_AUDIT)
+				 _TIF_SYSCALL_AUDIT | _TIF_SYSCALL_TRACEPOINT)
 
 /* work to do in syscall_trace_leave() */
 #define _TIF_WORK_SYSCALL_EXIT	(_TIF_NOHZ | _TIF_SYSCALL_TRACE |	\
-				 _TIF_SYSCALL_AUDIT)
+				 _TIF_SYSCALL_AUDIT | _TIF_SYSCALL_TRACEPOINT)
 
 /* work to do on interrupt/exception return */
 #define _TIF_WORK_MASK		\
 	(_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_NOTIFY_RESUME)
 /* work to do on any return to u-space */
 #define _TIF_ALLWORK_MASK	(_TIF_NOHZ | _TIF_WORK_MASK |		\
-				 _TIF_WORK_SYSCALL_EXIT)
+				 _TIF_WORK_SYSCALL_EXIT |		\
+				 _TIF_SYSCALL_TRACEPOINT)
 
 /*
  * We stash processor id into a COP0 register to retrieve it fast
diff --git a/arch/mips/include/asm/unistd.h b/arch/mips/include/asm/unistd.h
index 63c9c88..4d3b928 100644
--- a/arch/mips/include/asm/unistd.h
+++ b/arch/mips/include/asm/unistd.h
@@ -14,6 +14,13 @@
 
 #include <uapi/asm/unistd.h>
 
+#ifdef CONFIG_MIPS32_N32
+#define NR_syscalls  (__NR_N32_Linux + __NR_N32_Linux_syscalls)
+#elif defined(CONFIG_64BIT)
+#define NR_syscalls  (__NR_64_Linux + __NR_64_Linux_syscalls)
+#else
+#define NR_syscalls  (__NR_O32_Linux + __NR_O32_Linux_syscalls)
+#endif
 
 #ifndef __ASSEMBLY__