ARM: 7524/1: support syscall tracing

As specified by ftrace-design.txt, TIF_SYSCALL_TRACEPOINT was
added, as well as NR_syscalls in asm/unistd.h.  Additionally,
__sys_trace was modified to call trace_sys_enter and
trace_sys_exit when appropriate.

Tests #2 - #4 of "perf test" now complete successfully.

Signed-off-by: Steven Walter <stevenrwalter@gmail.com>
Signed-off-by: Wade Farnsworth <wade_farnsworth@mentor.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

6 files changed, 34 insertions, 3 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 2f88d8d97701..1382ef1142a3 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -16,6 +16,7 @@ config ARM
         select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL
         select HAVE_ARCH_KGDB
         select HAVE_ARCH_TRACEHOOK
+        select HAVE_SYSCALL_TRACEPOINTS
         select HAVE_KPROBES if !XIP_KERNEL
         select HAVE_KRETPROBES if (HAVE_KPROBES)
         select HAVE_FUNCTION_TRACER if (!XIP_KERNEL)
diff --git a/arch/arm/include/asm/syscall.h b/arch/arm/include/asm/syscall.h
index c334a23ddf75..47486a41c56e 100644
--- a/arch/arm/include/asm/syscall.h
+++ b/arch/arm/include/asm/syscall.h
@@ -9,6 +9,10 @@
 
 #include <linux/err.h>
 
+#include <asm/unistd.h>
+
+#define NR_syscalls (__NR_syscalls)
+
 extern const unsigned long sys_call_table[];
 
 static inline int syscall_get_nr(struct task_struct *task,
diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h
index af7b0bda3355..5ded667e330f 100644
--- a/arch/arm/include/asm/thread_info.h
+++ b/arch/arm/include/asm/thread_info.h
@@ -148,6 +148,7 @@ extern int vfp_restore_user_hwstate(struct user_vfp __user *,
 #define TIF_NOTIFY_RESUME       2       /* callback before returning to user */
 #define TIF_SYSCALL_TRACE       8
 #define TIF_SYSCALL_AUDIT       9
+#define TIF_SYSCALL_TRACEPOINT  10
 #define TIF_POLLING_NRFLAG      16
 #define TIF_USING_IWMMXT        17
 #define TIF_MEMDIE              18      /* is terminating due to OOM killer */
@@ -160,12 +161,13 @@ extern int vfp_restore_user_hwstate(struct user_vfp __user *,
 #define _TIF_NOTIFY_RESUME      (1 << TIF_NOTIFY_RESUME)
 #define _TIF_SYSCALL_TRACE      (1 << TIF_SYSCALL_TRACE)
 #define _TIF_SYSCALL_AUDIT      (1 << TIF_SYSCALL_AUDIT)
+#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
 #define _TIF_POLLING_NRFLAG     (1 << TIF_POLLING_NRFLAG)
 #define _TIF_USING_IWMMXT       (1 << TIF_USING_IWMMXT)
 #define _TIF_SECCOMP            (1 << TIF_SECCOMP)
 
 /* Checks for any syscall work in entry-common.S */
-#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT)
+#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SYSCALL_TRACEPOINT)
 
 /*
  * Change these and you break ASM code in entry-common.S
diff --git a/arch/arm/include/asm/unistd.h b/arch/arm/include/asm/unistd.h
index 0cab47d4a83f..a566ec20d486 100644
--- a/arch/arm/include/asm/unistd.h
+++ b/arch/arm/include/asm/unistd.h
@@ -406,6 +406,14 @@
 #define __NR_process_vm_writev          (__NR_SYSCALL_BASE+377)
 
 /*
+ * This may need to be greater than __NR_last_syscall+1 in order to
+ * account for the padding in the syscall table
+ */
+#ifdef __KERNEL__
+#define __NR_syscalls  (380)
+#endif /* __KERNEL__ */
+
+/*
  * The following SWIs are ARM private.
  */
 #define __ARM_NR_BASE                   (__NR_SYSCALL_BASE+0x0f0000)
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 978eac57e04a..f45987037bf1 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -94,6 +94,15 @@ ENDPROC(ret_from_fork)
         .equ NR_syscalls,0
 #define CALL(x) .equ NR_syscalls,NR_syscalls+1
 #include "calls.S"
+
+/*
+ * Ensure that the system call table is equal to __NR_syscalls,
+ * which is the value the rest of the system sees
+ */
+.ifne NR_syscalls - __NR_syscalls
+.error "__NR_syscalls is not equal to the size of the syscall table"
+.endif
+
 #undef CALL
 #define CALL(x) .long x
 
diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c
index 3e0fc5f7ed4b..c382d3c76ac6 100644
--- a/arch/arm/kernel/ptrace.c
+++ b/arch/arm/kernel/ptrace.c
@@ -30,6 +30,9 @@
 #include <asm/pgtable.h>
 #include <asm/traps.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/syscalls.h>
+
 #define REG_PC  15
 #define REG_PSR 16
 /*
@@ -918,11 +921,11 @@ static int ptrace_syscall_trace(struct pt_regs *regs, int scno,
 {
         unsigned long ip;
 
+        current_thread_info()->syscall = scno;
+
         if (!test_thread_flag(TIF_SYSCALL_TRACE))
                 return scno;
 
-        current_thread_info()->syscall = scno;
-
         /*
          * IP is used to denote syscall entry/exit:
          * IP = 0 -> entry, =1 -> exit
@@ -942,6 +945,8 @@ static int ptrace_syscall_trace(struct pt_regs *regs, int scno,
 asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno)
 {
         int ret = ptrace_syscall_trace(regs, scno, PTRACE_SYSCALL_ENTER);
+        if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
+                trace_sys_enter(regs, ret);
         audit_syscall_entry(AUDIT_ARCH_ARM, scno, regs->ARM_r0, regs->ARM_r1,
                             regs->ARM_r2, regs->ARM_r3);
         return ret;
@@ -950,6 +955,8 @@ asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno)
 asmlinkage int syscall_trace_exit(struct pt_regs *regs, int scno)
 {
         int ret = ptrace_syscall_trace(regs, scno, PTRACE_SYSCALL_EXIT);
+        if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
+                trace_sys_exit(regs, ret);
         audit_syscall_exit(regs);
         return ret;
 }