Module: xenomai-jki
Branch: for-forge
Commit: 781dbd912f6adec9719e9ff1d6ef866be29357fb
URL:
http://git.xenomai.org/?p=xenomai-jki.git;a=commit;h=781dbd912f6adec9719e9ff1d6ef866be29357fb
Author: Jan Kiszka <jan.kis...@siemens.com>
Date: Mon Jul 31 15:37:57 2017 +0200
cobalt: Introduce xnftrace_printf
This allows to inject a user-defined string into the system's ftrace
without leaving RT mode (because of using a standard write on
/sys/kernel/debug/tracing/trace_marker).
As the signature of this function is different from the existing trace
syscall, create as dedicated one.
For simplicity reasons, the maximum string length that can be passed
down to the kernel is limited to 255 characters (+1 for termination).
We call directly into the internal __trace_puts to avoid both the
unneeded strlen call of the trace_puts wrapper and the false warning
that kernel code uses trace_printk.
Signed-off-by: Jan Kiszka <jan.kis...@siemens.com>
---
include/cobalt/trace.h | 5 +++++
include/cobalt/uapi/syscall.h | 1 +
kernel/cobalt/posix/syscall.c | 17 +++++++++++++++++
lib/cobalt/trace.c | 29 +++++++++++++++++++++++++++++
4 files changed, 52 insertions(+)
diff --git a/include/cobalt/trace.h b/include/cobalt/trace.h
index 968eafa..172c0dc 100644
--- a/include/cobalt/trace.h
+++ b/include/cobalt/trace.h
@@ -22,6 +22,8 @@
extern "C" {
#endif
+#include <stdarg.h>
+
int xntrace_max_begin(unsigned long v);
int xntrace_max_end(unsigned long v);
@@ -38,6 +40,9 @@ int xntrace_special(unsigned char id, unsigned long v);
int xntrace_special_u64(unsigned char id, unsigned long long v);
+int xnftrace_vprintf(const char *format, va_list args);
+int xnftrace_printf(const char *format, ...);
+
#ifdef __cplusplus
}
#endif
diff --git a/include/cobalt/uapi/syscall.h b/include/cobalt/uapi/syscall.h
index 9c2ead1..cd7e820 100644
--- a/include/cobalt/uapi/syscall.h
+++ b/include/cobalt/uapi/syscall.h
@@ -117,6 +117,7 @@
#define sc_cobalt_backtrace 94
#define sc_cobalt_serialdbg 95
#define sc_cobalt_extend 96
+#define sc_cobalt_ftrace_puts 97
#define __NR_COBALT_SYSCALLS 128 /* Power of 2 */
diff --git a/kernel/cobalt/posix/syscall.c b/kernel/cobalt/posix/syscall.c
index 0f905bf..a70b705 100644
--- a/kernel/cobalt/posix/syscall.c
+++ b/kernel/cobalt/posix/syscall.c
@@ -180,6 +180,23 @@ static COBALT_SYSCALL(trace, current,
return ret;
}
+static COBALT_SYSCALL(ftrace_puts, current,
+ (const char __user *str))
+{
+ char buf[256];
+ unsigned len;
+
+ len = cobalt_strncpy_from_user(buf, str, sizeof(buf));
+ if (len < 0)
+ return -EFAULT;
+
+#ifdef CONFIG_TRACING
+ __trace_puts(_THIS_IP_, buf, len);
+#endif
+
+ return 0;
+}
+
static COBALT_SYSCALL(archcall, current,
(unsigned long a1, unsigned long a2,
unsigned long a3, unsigned long a4,
diff --git a/lib/cobalt/trace.c b/lib/cobalt/trace.c
index 48114aa..42e139f 100644
--- a/lib/cobalt/trace.c
+++ b/lib/cobalt/trace.c
@@ -15,6 +15,9 @@
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*/
+
+#include <errno.h>
+#include <stdio.h>
#include <cobalt/uapi/kernel/trace.h>
#include <cobalt/trace.h>
#include <asm/xenomai/syscall.h>
@@ -61,3 +64,29 @@ int xntrace_special_u64(unsigned char id, unsigned long long
v)
(unsigned long)(v >> 32),
(unsigned long)(v & 0xFFFFFFFF));
}
+
+int xnftrace_vprintf(const char *format, va_list args)
+{
+ char buf[256];
+ int ret;
+
+ ret = vsnprintf(buf, sizeof(buf), format, args);
+ if (ret < 0)
+ return ret;
+ if (ret >= sizeof(buf))
+ return -EOVERFLOW;
+
+ return XENOMAI_SYSCALL1(sc_cobalt_ftrace_puts, buf);
+}
+
+int xnftrace_printf(const char *format, ...)
+{
+ va_list args;
+ int ret;
+
+ va_start(args, format);
+ ret = xnftrace_vprintf(format, args);
+ va_end(args);
+
+ return ret;
+}
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