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[S390] add read_persistent_clock

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Add a read_persistent_clock function that does not just return 0.
Since timekeeping_init calls the function before time_init has been
called move reset_tod_clock to early.c to make sure that the TOD
clock is running when read_persistent_clock is invoked.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky 2009-04-14 15:36:28 +02:00
parent 5b409ed17b
commit b6112ccbff
4 changed files with 35 additions and 21 deletions
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5
arch/s390/include/asm/timex.h
View File

@ -11,6 +11,9 @@
#ifndef _ASM_S390_TIMEX_H
#define _ASM_S390_TIMEX_H
/* The value of the TOD clock for 1.1.1970. */
#define TOD_UNIX_EPOCH 0x7d91048bca000000ULL
/* Inline functions for clock register access. */
static inline int set_clock(__u64 time)
{
@ -85,4 +88,6 @@ int get_sync_clock(unsigned long long *clock);
void init_cpu_timer(void);
unsigned long long monotonic_clock(void);
extern u64 sched_clock_base_cc;
#endif

16
arch/s390/kernel/early.c
View File

@ -38,6 +38,21 @@ static unsigned long machine_flags;
static void __init setup_boot_command_line(void);
/*
* Get the TOD clock running.
*/
static void __init reset_tod_clock(void)
{
u64 time;
if (store_clock(&time) == 0)
return;
/* TOD clock not running. Set the clock to Unix Epoch. */
if (set_clock(TOD_UNIX_EPOCH) != 0 || store_clock(&time) != 0)
disabled_wait(0);
sched_clock_base_cc = TOD_UNIX_EPOCH;
}
#ifdef CONFIG_SHARED_KERNEL
int __init savesys_ipl_nss(char *cmd, const int cmdlen);
@ -372,6 +387,7 @@ static void __init setup_boot_command_line(void)
*/
void __init startup_init(void)
{
reset_tod_clock();
ipl_save_parameters();
rescue_initrd();
clear_bss_section();

7
arch/s390/kernel/head.S
View File

@ -471,6 +471,8 @@ startup:basr %r13,0 # get base
.LPG0:
xc 0x200(256),0x200 # partially clear lowcore
xc 0x300(256),0x300
l %r1,5f-.LPG0(%r13)
stck 0(%r1)
#ifndef CONFIG_MARCH_G5
# check processor version against MARCH_{G5,Z900,Z990,Z9_109,Z10}
@ -496,9 +498,10 @@ startup:basr %r13,0 # get base
brct %r0,0b
#endif
l %r13,0f-.LPG0(%r13)
l %r13,4f-.LPG0(%r13)
b 0(%r13)
0: .long startup_continue
4: .long startup_continue
5: .long sched_clock_base_cc
#
# params at 10400 (setup.h)

28
arch/s390/kernel/time.c
View File

@ -52,9 +52,6 @@
#define USECS_PER_JIFFY ((unsigned long) 1000000/HZ)
#define CLK_TICKS_PER_JIFFY ((unsigned long) USECS_PER_JIFFY << 12)
/* The value of the TOD clock for 1.1.1970. */
#define TOD_UNIX_EPOCH 0x7d91048bca000000ULL
/*
* Create a small time difference between the timer interrupts
* on the different cpus to avoid lock contention.
@ -63,9 +60,10 @@
#define TICK_SIZE tick
u64 sched_clock_base_cc = -1; /* Force to data section. */
static ext_int_info_t ext_int_info_cc;
static ext_int_info_t ext_int_etr_cc;
static u64 sched_clock_base_cc;
static DEFINE_PER_CPU(struct clock_event_device, comparators);
@ -195,22 +193,12 @@ static void timing_alert_interrupt(__u16 code)
static void etr_reset(void);
static void stp_reset(void);
/*
* Get the TOD clock running.
*/
static u64 __init reset_tod_clock(void)
unsigned long read_persistent_clock(void)
{
u64 time;
struct timespec ts;
etr_reset();
stp_reset();
if (store_clock(&time) == 0)
return time;
/* TOD clock not running. Set the clock to Unix Epoch. */
if (set_clock(TOD_UNIX_EPOCH) != 0 || store_clock(&time) != 0)
panic("TOD clock not operational.");
return TOD_UNIX_EPOCH;
tod_to_timeval(get_clock() - TOD_UNIX_EPOCH, &ts);
return ts.tv_sec;
}
static cycle_t read_tod_clock(void)
@ -265,7 +253,9 @@ void update_vsyscall_tz(void)
*/
void __init time_init(void)
{
sched_clock_base_cc = reset_tod_clock();
/* Reset time synchronization interfaces. */
etr_reset();
stp_reset();
/* set xtime */
tod_to_timeval(sched_clock_base_cc - TOD_UNIX_EPOCH, &xtime);