@@ -2,6 +2,8 @@
#ifndef _ASM_GENERIC_IO_INSTRUMENTED_H
#define _ASM_GENERIC_IO_INSTRUMENTED_H
+#include <linux/dynamic_debug.h>
+
#if defined(CONFIG_TRACING_EVENTS_IO)
#include <linux/tracepoint-defs.h>
@@ -19,7 +21,7 @@ static inline void do_trace_io_read(const char *type, void *addr) {}
#define __raw_write(v, a, _l) ({ \
volatile void __iomem *_a = (a); \
if (io_tracepoint_active(__tracepoint_io_write)) \
- do_trace_io_write(__stringify(write##_l), (void __force *)(_a));\
+ dynamic_io_write(__stringify(write##_l), (void __force *)(_a)); \
arch_raw_write##_l((v), _a); \
})
@@ -32,7 +34,7 @@ static inline void do_trace_io_read(const char *type, void *addr) {}
_t __a; \
const volatile void __iomem *_a = (a); \
if (io_tracepoint_active(__tracepoint_io_read)) \
- do_trace_io_read(__stringify(read##_l), (void __force *)(_a)); \
+ dynamic_io_read(__stringify(read##_l), (void __force *)(_a)); \
__a = arch_raw_read##_l(_a); \
__a; \
})
@@ -42,4 +44,26 @@ static inline void do_trace_io_read(const char *type, void *addr) {}
#define __raw_readl(a) __raw_read((a), l, u32)
#define __raw_readq(a) __raw_read((a), q, u64)
+#if defined(CONFIG_DYNAMIC_DEBUG) && defined(CONFIG_TRACING_EVENTS_IO)
+#define dynamic_io_write(type, addr) \
+do { \
+ DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, type); \
+ if (unlikely(descriptor.flags & _DPRINTK_FLAGS_EVENT)) \
+ do_trace_io_write(type, addr); \
+} while (0)
+
+#define dynamic_io_read(type, addr) \
+do { \
+ DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, type); \
+ if (unlikely(descriptor.flags & _DPRINTK_FLAGS_EVENT)) \
+ do_trace_io_read(type, addr); \
+} while (0)
+#elif defined(CONFIG_TRACING_EVENTS_IO)
+#define dynamic_io_write(type, addr) do_trace_io_write(type, addr)
+#define dynamic_io_read(type, addr) do_trace_io_read(type, addr)
+#else
+#define dynamic_io_write(type, addr)
+#define dynamic_io_read(type, addr)
+#endif /* CONFIG_DYNAMIC_DEBUG && CONFIG_TRACING_EVENTS_IO */
+
#endif /* _ASM_GENERIC_IO_INSTRUMENTED_H */
@@ -32,6 +32,7 @@ struct _ddebug {
#define _DPRINTK_FLAGS_INCL_FUNCNAME (1<<2)
#define _DPRINTK_FLAGS_INCL_LINENO (1<<3)
#define _DPRINTK_FLAGS_INCL_TID (1<<4)
+#define _DPRINTK_FLAGS_EVENT (1<<5)
#if defined DEBUG
#define _DPRINTK_FLAGS_DEFAULT _DPRINTK_FLAGS_PRINT
#else
@@ -78,6 +78,7 @@ static inline const char *trim_prefix(const char *path)
static struct { unsigned flag:8; char opt_char; } opt_array[] = {
{ _DPRINTK_FLAGS_PRINT, 'p' },
+ { _DPRINTK_FLAGS_EVENT, 'e' },
{ _DPRINTK_FLAGS_INCL_MODNAME, 'm' },
{ _DPRINTK_FLAGS_INCL_FUNCNAME, 'f' },
{ _DPRINTK_FLAGS_INCL_LINENO, 'l' },
Debugging a specific driver or subsystem can be a lot easier if we can trace events specific to that driver or subsystem. This type of filtering can be achieved using existing dynamic debug library which provides a way to filter based on files, functions and modules. Using this, provide an additional flag 'e' to filter event tracing to specified input. For example, tracing all IO read/write can be overwhelming and of no use when debugging a specific driver or a subsystem. So switch to dynamic event tracing for register accesses. Example for tracing register accesses in drivers/soc/qcom/* and the pstore output is given below: # dyndbg="file drivers/soc/qcom/* +e" trace_event=io tp_pstore # reboot -f # mount -t pstore pstore /sys/fs/pstore # cat /sys/fs/pstore/event-ramoops-0 io_write: type=writel cpu=1 ts:1423596253 data=0xffff00000d2065a4 caller=qcom_smsm_probe+0x524/0x670 io_write: type=writel cpu=1 ts:1423945889 data=0xffff00000d206608 caller=qcom_smsm_probe+0x524/0x670 Note: Tracing is activated only when flag is enabled either through command line or through dynamic debug control file. Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org> --- include/asm-generic/io-instrumented.h | 28 +++++++++++++++++++++++++-- include/linux/dynamic_debug.h | 1 + lib/dynamic_debug.c | 1 + 3 files changed, 28 insertions(+), 2 deletions(-)