Merge branches 'tracing/ftrace' and 'tracing/syscalls'; commit 'v2.6.29-rc8' into tracing/core

8 files changed, 161 insertions, 3 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index bdcee12c25ab..b0a638b4199a 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -35,6 +35,7 @@ config X86
         select HAVE_FUNCTION_GRAPH_TRACER
         select HAVE_FUNCTION_TRACE_MCOUNT_TEST
         select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
+        select HAVE_FTRACE_SYSCALLS
         select HAVE_KVM
         select HAVE_ARCH_KGDB
         select HAVE_ARCH_TRACEHOOK
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index df9d5f78385e..8820a73ae090 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -94,6 +94,7 @@ struct thread_info {
 #define TIF_FORCED_TF           24      /* true if TF in eflags artificially */
 #define TIF_DEBUGCTLMSR         25      /* uses thread_struct.debugctlmsr */
 #define TIF_DS_AREA_MSR         26      /* uses thread_struct.ds_area_msr */
+#define TIF_SYSCALL_FTRACE      27      /* for ftrace syscall instrumentation */
 
 #define _TIF_SYSCALL_TRACE      (1 << TIF_SYSCALL_TRACE)
 #define _TIF_NOTIFY_RESUME      (1 << TIF_NOTIFY_RESUME)
@@ -115,15 +116,17 @@ struct thread_info {
 #define _TIF_FORCED_TF          (1 << TIF_FORCED_TF)
 #define _TIF_DEBUGCTLMSR        (1 << TIF_DEBUGCTLMSR)
 #define _TIF_DS_AREA_MSR        (1 << TIF_DS_AREA_MSR)
+#define _TIF_SYSCALL_FTRACE     (1 << TIF_SYSCALL_FTRACE)
 
 /* work to do in syscall_trace_enter() */
 #define _TIF_WORK_SYSCALL_ENTRY \
-        (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU | \
+        (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU | _TIF_SYSCALL_FTRACE |  \
          _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | _TIF_SINGLESTEP)
 
 /* work to do in syscall_trace_leave() */
 #define _TIF_WORK_SYSCALL_EXIT  \
-        (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SINGLESTEP)
+        (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SINGLESTEP |    \
+         _TIF_SYSCALL_FTRACE)
 
 /* work to do on interrupt/exception return */
 #define _TIF_WORK_MASK                                                  \
@@ -132,7 +135,7 @@ struct thread_info {
            _TIF_SINGLESTEP|_TIF_SECCOMP|_TIF_SYSCALL_EMU))
 
 /* work to do on any return to user space */
-#define _TIF_ALLWORK_MASK (0x0000FFFF & ~_TIF_SECCOMP)
+#define _TIF_ALLWORK_MASK ((0x0000FFFF & ~_TIF_SECCOMP) | _TIF_SYSCALL_FTRACE)
 
 /* Only used for 64 bit */
 #define _TIF_DO_NOTIFY_MASK                                             \
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 3d9672e59c16..99749d6e87a8 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -21,6 +21,7 @@
 #include <linux/audit.h>
 #include <linux/seccomp.h>
 #include <linux/signal.h>
+#include <linux/ftrace.h>
 
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
@@ -1416,6 +1417,9 @@ asmregparm long syscall_trace_enter(struct pt_regs *regs)
             tracehook_report_syscall_entry(regs))
                 ret = -1L;
 
+        if (unlikely(test_thread_flag(TIF_SYSCALL_FTRACE)))
+                ftrace_syscall_enter(regs);
+
         if (unlikely(current->audit_context)) {
                 if (IS_IA32)
                         audit_syscall_entry(AUDIT_ARCH_I386,
@@ -1439,6 +1443,9 @@ asmregparm void syscall_trace_leave(struct pt_regs *regs)
         if (unlikely(current->audit_context))
                 audit_syscall_exit(AUDITSC_RESULT(regs->ax), regs->ax);
 
+        if (unlikely(test_thread_flag(TIF_SYSCALL_FTRACE)))
+                ftrace_syscall_exit(regs);
+
         if (test_thread_flag(TIF_SYSCALL_TRACE))
                 tracehook_report_syscall_exit(regs, 0);
 
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index e1583f2639b0..c146c1021a29 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -503,4 +503,25 @@ static inline void trace_hw_branch_oops(void) {}
 
 #endif /* CONFIG_HW_BRANCH_TRACER */
 
+/*
+ * A syscall entry in the ftrace syscalls array.
+ *
+ * @syscall_nr: syscall number
+ */
+struct syscall_trace_entry {
+        int             syscall_nr;
+};
+
+#ifdef CONFIG_FTRACE_SYSCALLS
+extern void start_ftrace_syscalls(void);
+extern void stop_ftrace_syscalls(void);
+extern void ftrace_syscall_enter(struct pt_regs *regs);
+extern void ftrace_syscall_exit(struct pt_regs *regs);
+#else
+static inline void start_ftrace_syscalls(void) { }
+static inline void stop_ftrace_syscalls(void) { }
+static inline void ftrace_syscall_enter(struct pt_regs *regs) { }
+static inline void ftrace_syscall_exit(struct pt_regs *regs) { }
+#endif
+
 #endif /* _LINUX_FTRACE_H */
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 8e4a2a61cd75..95a0ad191f19 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -34,6 +34,9 @@ config HAVE_FTRACE_MCOUNT_RECORD
 config HAVE_HW_BRANCH_TRACER
         bool
 
+config HAVE_FTRACE_SYSCALLS
+        bool
+
 config TRACER_MAX_TRACE
         bool
 
@@ -175,6 +178,13 @@ config EVENT_TRACER
           allowing the user to pick and choose which trace point they
           want to trace.
 
+config FTRACE_SYSCALLS
+        bool "Trace syscalls"
+        depends on HAVE_FTRACE_SYSCALLS
+        select TRACING
+        help
+          Basic tracer to catch the syscall entry and exit events.
+
 config BOOT_TRACER
         bool "Trace boot initcalls"
         select TRACING
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index c7a2943796eb..c3feea01c3e0 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -43,5 +43,6 @@ obj-$(CONFIG_BLK_DEV_IO_TRACE)	+= blktrace.o
 obj-$(CONFIG_EVENT_TRACER) += trace_events.o
 obj-$(CONFIG_EVENT_TRACER) += events.o
 obj-$(CONFIG_EVENT_TRACER) += trace_export.o
+obj-$(CONFIG_FTRACE_SYSCALLS) += trace_syscalls.o
 
 libftrace-y := ftrace.o
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 67595b8f0f15..56ce34d90b03 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -31,6 +31,8 @@ enum trace_type {
         TRACE_GRAPH_ENT,
         TRACE_USER_STACK,
         TRACE_HW_BRANCHES,
+        TRACE_SYSCALL_ENTER,
+        TRACE_SYSCALL_EXIT,
         TRACE_KMEM_ALLOC,
         TRACE_KMEM_FREE,
         TRACE_POWER,
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
new file mode 100644
index 000000000000..66cf97449af3
--- /dev/null
+++ b/kernel/trace/trace_syscalls.c
@@ -0,0 +1,113 @@
+#include <linux/ftrace.h>
+#include <linux/kernel.h>
+
+#include <asm/syscall.h>
+
+#include "trace_output.h"
+#include "trace.h"
+
+static atomic_t refcount;
+
+void start_ftrace_syscalls(void)
+{
+        unsigned long flags;
+        struct task_struct *g, *t;
+
+        if (atomic_inc_return(&refcount) != 1)
+                goto out;
+
+        read_lock_irqsave(&tasklist_lock, flags);
+
+        do_each_thread(g, t) {
+                set_tsk_thread_flag(t, TIF_SYSCALL_FTRACE);
+        } while_each_thread(g, t);
+
+        read_unlock_irqrestore(&tasklist_lock, flags);
+out:
+        atomic_dec(&refcount);
+}
+
+void stop_ftrace_syscalls(void)
+{
+        unsigned long flags;
+        struct task_struct *g, *t;
+
+        if (atomic_dec_return(&refcount))
+                goto out;
+
+        read_lock_irqsave(&tasklist_lock, flags);
+
+        do_each_thread(g, t) {
+                clear_tsk_thread_flag(t, TIF_SYSCALL_FTRACE);
+        } while_each_thread(g, t);
+
+        read_unlock_irqrestore(&tasklist_lock, flags);
+out:
+        atomic_inc(&refcount);
+}
+
+void ftrace_syscall_enter(struct pt_regs *regs)
+{
+        int syscall_nr;
+
+        syscall_nr = syscall_get_nr(current, regs);
+
+        trace_printk("syscall %d enter\n", syscall_nr);
+}
+
+void ftrace_syscall_exit(struct pt_regs *regs)
+{
+        int syscall_nr;
+
+        syscall_nr = syscall_get_nr(current, regs);
+
+        trace_printk("syscall %d exit\n", syscall_nr);
+}
+
+static int init_syscall_tracer(struct trace_array *tr)
+{
+        start_ftrace_syscalls();
+
+        return 0;
+}
+
+static void reset_syscall_tracer(struct trace_array *tr)
+{
+        stop_ftrace_syscalls();
+}
+
+static struct trace_event syscall_enter_event = {
+        .type           = TRACE_SYSCALL_ENTER,
+};
+
+static struct trace_event syscall_exit_event = {
+        .type           = TRACE_SYSCALL_EXIT,
+};
+
+static struct tracer syscall_tracer __read_mostly = {
+        .name           = "syscall",
+        .init           = init_syscall_tracer,
+        .reset          = reset_syscall_tracer
+};
+
+__init int register_ftrace_syscalls(void)
+{
+        int ret;
+
+        ret = register_ftrace_event(&syscall_enter_event);
+        if (!ret) {
+                printk(KERN_WARNING "event %d failed to register\n",
+                       syscall_enter_event.type);
+                WARN_ON_ONCE(1);
+        }
+
+        ret = register_ftrace_event(&syscall_exit_event);
+        if (!ret) {
+                printk(KERN_WARNING "event %d failed to register\n",
+                       syscall_exit_event.type);
+                WARN_ON_ONCE(1);
+        }
+
+        return register_tracer(&syscall_tracer);
+}
+device_initcall(register_ftrace_syscalls);