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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2016-10-27 13:41:39 +0300
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2017-07-26 09:25:14 +0300
commit6e2ef5e4f6cc57344762932d70d38ba4ec65fa8b (patch)
tree51e148a3b1e6991260af2ac51e6b1a6d5eb0f83a /arch/s390/include/asm/lowcore.h
parent45be0a02f8110a13502fac6167a893c7c0eff432 (diff)
downloadlinux-6e2ef5e4f6cc57344762932d70d38ba4ec65fa8b.tar.xz
s390/time: add support for the TOD clock epoch extension
The TOD epoch extension adds 8 epoch bits to the TOD clock to provide a continuous clock after 2042/09/17. The store-clock-extended (STCKE) instruction will store the epoch index in the first byte of the 16 bytes stored by the instruction. The read_boot_clock64 and the read_presistent_clock64 functions need to take the additional bits into account to give the correct result after 2042/09/17. The clock-comparator register will stay 64 bit wide. The comparison of the clock-comparator with the TOD clock is limited to bytes 1 to 8 of the extended TOD format. To deal with the overflow problem due to an epoch change the clock-comparator sign control in CR0 can be used to switch the comparison of the 64-bit TOD clock with the clock-comparator to a signed comparison. The decision between the signed vs. unsigned clock-comparator comparisons is done at boot time. Only if the TOD clock is in the second half of a 142 year epoch the signed comparison is used. This solves the epoch overflow issue as long as the machine is booted at least once in an epoch. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/include/asm/lowcore.h')
-rw-r--r--arch/s390/include/asm/lowcore.h48
1 files changed, 24 insertions, 24 deletions
diff --git a/arch/s390/include/asm/lowcore.h b/arch/s390/include/asm/lowcore.h
index 8a5b082797f8..a6870ea6ea8b 100644
--- a/arch/s390/include/asm/lowcore.h
+++ b/arch/s390/include/asm/lowcore.h
@@ -95,46 +95,46 @@ struct lowcore {
__u64 int_clock; /* 0x0310 */
__u64 mcck_clock; /* 0x0318 */
__u64 clock_comparator; /* 0x0320 */
+ __u64 boot_clock[2]; /* 0x0328 */
/* Current process. */
- __u64 current_task; /* 0x0328 */
- __u8 pad_0x318[0x320-0x318]; /* 0x0330 */
- __u64 kernel_stack; /* 0x0338 */
+ __u64 current_task; /* 0x0338 */
+ __u64 kernel_stack; /* 0x0340 */
/* Interrupt, panic and restart stack. */
- __u64 async_stack; /* 0x0340 */
- __u64 panic_stack; /* 0x0348 */
- __u64 restart_stack; /* 0x0350 */
+ __u64 async_stack; /* 0x0348 */
+ __u64 panic_stack; /* 0x0350 */
+ __u64 restart_stack; /* 0x0358 */
/* Restart function and parameter. */
- __u64 restart_fn; /* 0x0358 */
- __u64 restart_data; /* 0x0360 */
- __u64 restart_source; /* 0x0368 */
+ __u64 restart_fn; /* 0x0360 */
+ __u64 restart_data; /* 0x0368 */
+ __u64 restart_source; /* 0x0370 */
/* Address space pointer. */
- __u64 kernel_asce; /* 0x0370 */
- __u64 user_asce; /* 0x0378 */
+ __u64 kernel_asce; /* 0x0378 */
+ __u64 user_asce; /* 0x0380 */
/*
* The lpp and current_pid fields form a
* 64-bit value that is set as program
* parameter with the LPP instruction.
*/
- __u32 lpp; /* 0x0380 */
- __u32 current_pid; /* 0x0384 */
+ __u32 lpp; /* 0x0388 */
+ __u32 current_pid; /* 0x038c */
/* SMP info area */
- __u32 cpu_nr; /* 0x0388 */
- __u32 softirq_pending; /* 0x038c */
- __u64 percpu_offset; /* 0x0390 */
- __u64 vdso_per_cpu_data; /* 0x0398 */
- __u64 machine_flags; /* 0x03a0 */
- __u32 preempt_count; /* 0x03a8 */
- __u8 pad_0x03ac[0x03b0-0x03ac]; /* 0x03ac */
- __u64 gmap; /* 0x03b0 */
- __u32 spinlock_lockval; /* 0x03b8 */
- __u32 fpu_flags; /* 0x03bc */
- __u8 pad_0x03c0[0x0400-0x03c0]; /* 0x03c0 */
+ __u32 cpu_nr; /* 0x0390 */
+ __u32 softirq_pending; /* 0x0394 */
+ __u64 percpu_offset; /* 0x0398 */
+ __u64 vdso_per_cpu_data; /* 0x03a0 */
+ __u64 machine_flags; /* 0x03a8 */
+ __u32 preempt_count; /* 0x03b0 */
+ __u8 pad_0x03b4[0x03b8-0x03b4]; /* 0x03b4 */
+ __u64 gmap; /* 0x03b8 */
+ __u32 spinlock_lockval; /* 0x03c0 */
+ __u32 fpu_flags; /* 0x03c4 */
+ __u8 pad_0x03c8[0x0400-0x03c8]; /* 0x03c8 */
/* Per cpu primary space access list */
__u32 paste[16]; /* 0x0400 */