MIPS: ftrace: Add support for syscall tracepoints.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/Kconfig

@@ -19,6 +19,7 @@ config MIPS
 	select HAVE_KPROBES
 	select HAVE_KRETPROBES
 	select HAVE_DEBUG_KMEMLEAK
+	select HAVE_SYSCALL_TRACEPOINTS
 	select ARCH_BINFMT_ELF_RANDOMIZE_PIE
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE if CPU_SUPPORTS_HUGEPAGES && 64BIT
 	select RTC_LIB if !MACH_LOONGSON

arch/mips/include/asm/syscall.h

@@ -59,6 +59,25 @@ static inline unsigned long mips_get_syscall_arg(unsigned long *arg,
 	}
 }
 
+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,

arch/mips/include/asm/thread_info.h

@@ -116,6 +116,7 @@ static inline struct thread_info *current_thread_info(void)
 #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 @@ static inline struct thread_info *current_thread_info(void)
 #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

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__
 

arch/mips/kernel/ptrace.c

@@ -29,6 +29,7 @@
 #include <linux/tracehook.h>
 #include <linux/audit.h>
 #include <linux/seccomp.h>
+#include <linux/ftrace.h>
 
 #include <asm/byteorder.h>
 #include <asm/cpu.h>
@@ -43,6 +44,9 @@
 #include <asm/bootinfo.h>
 #include <asm/reg.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/syscalls.h>
+
 /*
  * Called by kernel/ptrace.c when detaching..
  *
@@ -664,6 +668,9 @@ asmlinkage void syscall_trace_enter(struct pt_regs *regs)
 	    tracehook_report_syscall_entry(regs))
 		ret = -1;
 
+	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
+		trace_sys_enter(regs, regs->regs[2]);
+
 	audit_syscall_entry(__syscall_get_arch(),
 			    regs->regs[2],
 			    regs->regs[4], regs->regs[5],
@@ -685,6 +692,9 @@ asmlinkage void syscall_trace_leave(struct pt_regs *regs)
 
 	audit_syscall_exit(regs);
 
+	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
+		trace_sys_exit(regs, regs->regs[2]);
+
 	if (test_thread_flag(TIF_SYSCALL_TRACE))
 		tracehook_report_syscall_exit(regs, 0);