[PATCH] printk_time: prepare stub for using other than cpu_clock

Yinghai Lu
2008-08-27T07:40:11Z

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>

---
include/linux/kernel.h | 5 +++++
init/main.c | 1 +
kernel/printk.c | 14 +++++++++++++-
3 files changed, 19 insertions(+), 1 deletion(-)

Index: linux-2.6/include/linux/kernel.h
===================================================================
--- linux-2.6.orig/include/linux/kernel.h
+++ linux-2.6/include/linux/kernel.h
@@ -190,7 +190,10 @@ extern int kernel_text_address(unsigned
struct pid;
extern struct pid *session_of_pgrp(struct pid *pgrp);

+typedef unsigned long long (*printk_time_clock_fn)(int cpu);
#ifdef CONFIG_PRINTK
+extern void set_printk_time_clock(printk_time_clock_fn fn);
+
asmlinkage int vprintk(const char *fmt, va_list args)
__attribute__ ((format (printf, 1, 0)));
asmlinkage int printk(const char * fmt, ...)
@@ -201,6 +204,8 @@ extern int printk_ratelimit(void);
extern bool printk_timed_ratelimit(unsigned long *caller_jiffies,
unsigned int interval_msec);
#else
+static inline void set_printk_time_clock(printk_time_clock_fn fn) { }
+
static inline int vprintk(const char *s, va_list args)
__attribute__ ((format (printf, 1, 0)));
static inline int vprintk(const char *s, va_list args) { return 0; }
Index: linux-2.6/init/main.c
===================================================================
--- linux-2.6.orig/init/main.c
+++ linux-2.6/init/main.c
@@ -671,6 +671,7 @@ asmlinkage void __init start_kernel(void
if (late_time_init)
late_time_init();
calibrate_delay();
+ set_printk_time_clock(cpu_clock);
pidmap_init();
pgtable_cache_init();
prio_tree_init();
Index: linux-2.6/kernel/printk.c
===================================================================
--- linux-2.6.orig/kernel/printk.c
+++ linux-2.6/kernel/printk.c
@@ -659,6 +659,18 @@ static int recursion_bug;
static int new_text_line = 1;
static char printk_buf[1024];

+static unsigned long long default_printk_time_clock(int cpu)
+{
+ return 0;
+}
+
+static printk_time_clock_fn printk_time_clock = default_printk_time_clock;
+
+void set_printk_time_clock(printk_time_clock_fn fn)
+{
+ printk_time_clock = fn;
+}
+
asmlinkage int vprintk(const char *fmt, va_list args)
{
int printed_len = 0;
@@ -734,7 +746,7 @@ asmlinkage int vprintk(const char *fmt,
unsigned long long t;
unsigned long nanosec_rem;

- t = cpu_clock(printk_cpu);
+ t = printk_time_clock(printk_cpu);
nanosec_rem = do_div(t, 1000000000);
tlen = sprintf(tbuf, "[%5lu.%06lu] ",
(unsigned long) t,