[PATCH 5/6] trace: raw_syscalls: Mark compat syscalls in the MSB of the syscall number

[Vaibhav Nagarnaik <vnagarnaik@google.com>]

From: David Sharp <dhsharp@google.com>

The compat syscalls are undifferentiable from standard syscalls, making
correct interpretation of 'id' impossible on systems where compat tasks
are running. Set the MSB of 'id' if the traced syscall is compat, and
output this bit in the print format.

Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com>
---
 include/trace/events/syscalls.h |   23 ++++++++++++++++++-----
 1 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/include/trace/events/syscalls.h b/include/trace/events/syscalls.h
index aeaa536..4f42fdc 100644
--- a/include/trace/events/syscalls.h
+++ b/include/trace/events/syscalls.h
@@ -6,10 +6,13 @@
 #define _TRACE_EVENTS_SYSCALLS_H
 
 #include <linux/tracepoint.h>
+#include <linux/compat.h>
 
 #include <asm/ptrace.h>
 #include <asm/syscall.h>
 
+#define COMPAT_MASK (~0UL>>1)
+#define COMPAT_BIT ~(~0UL>>1)
 
 TRACE_EVENT(sys_enter,
 
@@ -23,14 +26,19 @@ TRACE_EVENT(sys_enter,
 	),
 
 	TP_fast_assign(
+#ifdef CONFIG_COMPAT
+		if (is_compat_task())
+			id |= COMPAT_BIT;
+#endif
 		__entry->id	= id;
 		syscall_get_arguments(current, regs, 0, 6, __entry->args);
 	),
 
-	TP_printk("NR %ld (%lx, %lx, %lx, %lx, %lx, %lx)",
-		  __entry->id,
+	TP_printk("NR %ld (%lx, %lx, %lx, %lx, %lx, %lx) isCompat: %d",
+		  __entry->id & COMPAT_MASK,
 		  __entry->args[0], __entry->args[1], __entry->args[2],
-		  __entry->args[3], __entry->args[4], __entry->args[5])
+		  __entry->args[3], __entry->args[4], __entry->args[5],
+		  !!(__entry->id & COMPAT_BIT))
 );
 
 TRACE_EVENT_FLAGS(sys_enter, TRACE_EVENT_FL_CAP_ANY)
@@ -48,11 +56,16 @@ TRACE_EVENT(sys_exit,
 
 	TP_fast_assign(
 		__entry->id	= syscall_get_nr(current, regs);
+#ifdef CONFIG_COMPAT
+		if (is_compat_task())
+			__entry->id |= COMPAT_BIT;
+#endif
 		__entry->ret	= ret;
 	),
 
-	TP_printk("NR %ld = %ld",
-		  __entry->id, __entry->ret)
+	TP_printk("NR %ld = %ld isCompat: %d",
+		  __entry->id & COMPAT_MASK, __entry->ret,
+		  !!(__entry->id & COMPAT_BIT))
 );
 
 TRACE_EVENT_FLAGS(sys_exit, TRACE_EVENT_FL_CAP_ANY)
-- 
1.7.7.3