From a332365630712b42e8edcd63085876da893e2de7 Mon Sep 17 00:00:00 2001
From: Martin Schwidefsky <schwidefsky@de.ibm.com>
Date: Tue, 29 Nov 2016 10:44:22 -0700
Subject: [PATCH] s390/time: STP sync clock correction
BugLink: http://bugs.launchpad.net/bugs/1644505
The sync clock operation of the channel subsystem call for STP delivers
the TOD clock difference as a result. Use this TOD clock difference
instead of the difference between the TOD timestamps before and after
the sync clock operation.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
(cherry picked from commit 2f82f57763d97700788cf228de1cf30ffd4153b4)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
arch/s390/include/asm/cio.h | 2 +-
arch/s390/kernel/time.c | 11 +++++------
drivers/s390/cio/chsc.c | 8 ++++++--
3 files changed, 12 insertions(+), 9 deletions(-)
diff --git a/arch/s390/include/asm/cio.h b/arch/s390/include/asm/cio.h
index d1e7b0a0feeb..f7ed88cc066e 100644
--- a/arch/s390/include/asm/cio.h
+++ b/arch/s390/include/asm/cio.h
@@ -320,7 +320,7 @@ struct cio_iplinfo {
extern int cio_get_iplinfo(struct cio_iplinfo *iplinfo);
/* Function from drivers/s390/cio/chsc.c */
-int chsc_sstpc(void *page, unsigned int op, u16 ctrl);
+int chsc_sstpc(void *page, unsigned int op, u16 ctrl, u64 *clock_delta);
int chsc_sstpi(void *page, void *result, size_t size);
#endif
diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c
index 99f84ac31307..1a94242ef1c3 100644
--- a/arch/s390/kernel/time.c
+++ b/arch/s390/kernel/time.c
@@ -1460,7 +1460,7 @@ static void __init stp_reset(void)
int rc;
stp_page = (void *) get_zeroed_page(GFP_ATOMIC);
- rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000);
+ rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000, NULL);
if (rc == 0)
set_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags);
else if (stp_online) {
@@ -1560,11 +1560,10 @@ static int stp_sync_clock(void *data)
stp_info.todoff[2] || stp_info.todoff[3] ||
stp_info.tmd != 2) {
old_clock = get_tod_clock();
- rc = chsc_sstpc(stp_page, STP_OP_SYNC, 0);
+ rc = chsc_sstpc(stp_page, STP_OP_SYNC, 0, &clock_delta);
if (rc == 0) {
- new_clock = get_tod_clock();
+ new_clock = old_clock + clock_delta;
delta = adjust_time(old_clock, new_clock, 0);
- clock_delta = new_clock - old_clock;
atomic_notifier_call_chain(&s390_epoch_delta_notifier,
0, &clock_delta);
fixup_clock_comparator(delta);
@@ -1596,12 +1595,12 @@ static void stp_work_fn(struct work_struct *work)
mutex_lock(&stp_work_mutex);
if (!stp_online) {
- chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000);
+ chsc_sstpc(stp_page, STP_OP_CTRL, 0x0000, NULL);
del_timer_sync(&stp_timer);
goto out_unlock;
}
- rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0xb0e0);
+ rc = chsc_sstpc(stp_page, STP_OP_CTRL, 0xb0e0, NULL);
if (rc)
goto out_unlock;
diff --git a/drivers/s390/cio/chsc.c b/drivers/s390/cio/chsc.c
index 1e16331891a9..c38259339d01 100644
--- a/drivers/s390/cio/chsc.c
+++ b/drivers/s390/cio/chsc.c
@@ -1180,7 +1180,7 @@ chsc_determine_css_characteristics(void)
EXPORT_SYMBOL_GPL(css_general_characteristics);
EXPORT_SYMBOL_GPL(css_chsc_characteristics);
-int chsc_sstpc(void *page, unsigned int op, u16 ctrl)
+int chsc_sstpc(void *page, unsigned int op, u16 ctrl, u64 *clock_delta)
{
struct {
struct chsc_header request;
@@ -1190,7 +1190,9 @@ int chsc_sstpc(void *page, unsigned int op, u16 ctrl)
unsigned int ctrl : 16;
unsigned int rsvd2[5];
struct chsc_header response;
- unsigned int rsvd3[7];
+ unsigned int rsvd3[3];
+ u64 clock_delta;
+ unsigned int rsvd4[2];
} __attribute__ ((packed)) *rr;
int rc;
@@ -1204,6 +1206,8 @@ int chsc_sstpc(void *page, unsigned int op, u16 ctrl)
if (rc)
return -EIO;
rc = (rr->response.code == 0x0001) ? 0 : -EIO;
+ if (clock_delta)
+ *clock_delta = rr->clock_delta;
return rc;
}
--
2.30.9