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>

2 files changed, 18 insertions, 2 deletions

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;
 }